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Drinking Water Research Articles Archive

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2007

Air-Water Exchange of Polychlorinated Biphenyls in the Delaware River
Authors: Amy A. Rowe, Lisa A. Totten,* Minge Xie, Thomas J. Fikslin, and Stephen J. Eisenreich
Affiliations: Department of Environmental Sciences, Rutgers University, 14 College Farm, Road, New Brunswick, New Jersey 08901, USA, Department of Statistics, Rutgers University, 110 Frelinghuysen Road, Piscataway, New Jersey 08854 USA, Delaware River Basin Commission, 25 State Police Drive, West Trenton, New Jersey 08628, USA, and Toxicology and Chemical Substances Unit, European Commission, Joint Research Centre, TP 582, I-21020 Ispra (VA), Italy
Source: Environmental Science Technology, January 17, 2007, 41(4); 1152 -1158

Abstract: The air-water exchange of polychlorinated biphenyls (PCBs) often results in net volatilization, which is thought to be the most important loss process for PCBs in many systems. Previous investigations of the air-water exchange of PCBs have been hampered by difficulties in treatment of the uncertainty in the calculation of air/water fugacity ratios. This work presents a new framework for the treatment of uncertainty, where uncertainty in physical constants is handled differently from random measurement uncertainty associated with random samples, and it further investigates the sorption of PCBs to colloids (dissolved organic carbon). Simultaneous measurements of PCBs in the air and water of five water quality management zones of the Delaware River were taken in 2002 in support of the total maximum daily load (TMDL) process. Gas-phase concentrations of PCBs ranged from 110 to 1350 pg m-3, while dissolved water concentrations were between 420 and 1650 pg L-1. Shallow slopes of log KOC vs log KOW plots indicated a colloidal contribution to the apparent dissolved-phase concentrations, such that a three-phase partitioning model was applied. Fugacity ratios for individual congeners were calculated under the most conservative assumptions, and their values (log-transformed) were examined via a single-sample T-test to determine whether they were significantly less than 1 at the 95% confidence level. This method demonstrated that air-water exchange resulted in net volatilization in all zones over all cruises for all but seven high molecular weight congeners. Calculated net fluxes ranged from +360 to +3000 ng m-2 d-1 for PCBs. The colloidal correction decreased the volatilization flux of PCBs by ~30%. The decachlorinated congener (PCB 209), exhibited unusually high concentrations in the suspended solids, especially in the southern portions of the river, indicating that there is a distinct Source: of PCB 209 in the Delaware River.

Analysis of Lagoon Samples from Different Concentrated Animal Feeding Operations for Estrogens and Estrogen Conjugates
Authors: Stephen R. Hutchins, Mark V. White, Felisa M. Hudson and Dennis D. Fine
Affiliations: Ground Water and Ecosystems Restoration Division, National Risk Management Research Laboratory, U.S. Environmental Protection Agency, P.O. Box 1198, Ada, Oklahoma 74821-1198, and Shaw Environmental and Infrastructure, P.O. Box 1198, Ada, Oklahoma 74821-1198
Source: Environmental Science Technology, January 4, 2007, 41(3): 738 -744

Abstract: Although Concentrated Animal Feeding Operations (CAFOs) have been identified as potentially important Source:s for the release of estrogens into the environment, information is lacking on the concentrations of estrogens in whole lagoon effluents (including suspended solids) which are used for land application. Lagoons associated with swine, poultry, and cattle operations were sampled at three locations each for direct analysis for estrogens by GC/MS/MS and estrogen conjugates by LC/MS/MS. Estrogen conjugates were also analyzed indirectly by first subjecting the same samples to enzyme hydrolysis. Solids from centrifuged samples were extracted for free estrogens to estimate total estrogen load. Total free estrogen levels (estrone, 17 -estradiol, 17 -estradiol, estriol) were generally higher in swine primary (1000-21000 ng/L), followed by poultry primary (1800-4000 ng/L), dairy secondary (370-550 ng/L), and beef secondary (22-24 ng/L) whole lagoon samples. Swine and poultry lagoons contained levels of 17 -estradiol comparable to those of 17 -estradiol. Confirmed estrogen conjugates included estrone-3-sulfate (2-91 ng/L), 17 -estradiol-3-sulfate (8-44 ng/L), 17 -estradiol-3-sulfate (141-182 ng/L), and 17 -estradiol-17-sulfate (72-84 ng/L) in some lagoons. Enzymatic hydrolysis indicated the presence of additional unidentified estrogen conjugates not detected by the LC/MS/MS method. In most cases estrogen conjugates accounted for at least a third of the total estrogen equivalents. Collectively, these methods can be used to better determine estrogen loads from CAFO operations, and this research shows that estrogen conjugates contribute significantly to the overall estrogen load, even in different types of CAFO lagoons.

Anticipating Effects of Water Quality Changes on Iron Corrosion and Red Water
Authors: Yan Zhang and Marc Edwards
Source: Journal of Water Supply: Research and Technology-AQUA, 2007, 56(1): 55-68

Abstract: This study investigated the effect of disinfectant, sulfate/chloride ratios, nitrate concentration, magnesium hardness and zinc on iron corrosion. For the waters tested, free chlorine better controlled red water and microbial activity in the bulk solution. Consistent with predictions based on Larson's ratio, sulfate/chloride ratio changes did not have an effect on overall iron corrosion rates, although higher chloride was associated with increased localization of corrosion and pitting. High levels of nitrate increased the rate of chlorine decay and caused release of more iron, but had no effect on chloramine decay rates. The concentration of nitrate in the water might therefore be an important factor in considering the relative merits of chloramine versus chlorine as secondary disinfectants in real distribution systems. Increased magnesium and zinc can decrease mobilization of iron (e.g. red water) caused by silicate.

Aquatic Ecosystem Protection and Drinking Water Utilities
Author: Postel, Sandra L.
Source: Journal AWWA, February 2007, 99(2):52-63

Abstract: Aquatic ecosystems provide irreplaceable benefits, including water supplies, food for people and wildlife, water purification and filtration of pollutants, flood and drought mitigation, even recreational opportunities. As the economic and ecologic services provided by aquatic ecosystems gain more recognition and the deleterious effects of mismanaging water resources become more apparent, the global water community is taking steps toward ecologically sustainable water management. Because their operations have significant and far-reaching consequences for aquatic ecosystems, drinking water providers can play a major role in safeguarding the health of these systems. Strategies to protect aquatic ecosystems include reducing water demand through conservation, managing water within the bounds of an ecological flow prescription, planning for ecosystem allocation during drought, and protecting source watersheds. With urban populations growing and water demands on the rise, utilities must act now to ensure that the benefits provided by healthy aquatic ecosystems are available to future generations.

Are Nitrate Levels in Groundwater Stable Over Time?
Authors: Perri Zeitz Ruckart, Alden K Henderson, Michele Lynberg Black and W Dana Flanders
Affilations: Agency for Toxic Substances and Disease Registry, Atlanta, Georgia, USA, Centers for Disease Control and Prevention, National Center for Injury Prevention and Control, Atlanta, Georgia, USA, Centers for Disease Control and Prevention, National Center for Environmental Health, Atlanta, Georgia, USA
Source: Journal of Exposure Science and Environmental Epidemiology, April 11, 2007

Abstract: Epidemiologists often use a retrospective study design to examine for associations between an exposure and the occurrence of adverse health effects. Several of these studies used this approach to examine for an association between elevated levels of nitrate in drinking water and related health effects such as methemoglobinemia, cancer, neural tube effects, or spontaneous abortions. Often, data on exposures that occurred before these health outcomes were not available. Consequently, researchers use measurements of exposures at the time of the study to represent exposures that occurred before people developed these conditions. An opportunity to examine the stability of nitrate in water occurred during a survey of private water wells in nine Midwestern states. In this survey, water samples from 853 homes with drilled wells were collected in May 1994 and in September 1995 and nitrate-nitrogen (nitrate-N) was measured by the colorimetric cadmium reduction method. Nitrate-N levels from the same well over time were assessed by a mixed-effects analysis of variance. Analysis showed no significant difference in between the initial level and those measured 16 months later. Furthermore, analysis showed that most of the variance in the nitrate concentrations in well water was due to well-to-well variation (89%) rather than to residual error (12%). This observation showed that a single measurement of nitrate in water from drilled wells could represent longer periods of exposure.

Biological Nutrient Removal: Where We Have Been, Where We Are Going?
Author: James l. Barnard
Affiliation: Black & Veatch, Kansas City MO
Source: WEFTEC®.06

Abstract: The paper covers the early research that led to the development of the biological nutrient removal (BNR) technology that is widely practiced today then looks at the present and future of BNR. Presently only suspended and attached growth biological processes or a combination of the two are used to reduce nitrogen concentration to around 3 mg/L. New technologies such as the SHARON® and ANAMMOX® processes are being developed to utilize autotrophic denitrification when treating high strength ammonia streams, reducing or eliminating the need for carbon addition. The concentration of recalcitrant dissolved organic nitrogen (rDON) which cannot be removed by biological processes will determine the limits to which nitrogen can be reduced. Phosphorus can be removed effectively to very low levels by using chemicals; however, biological treatment can remove phosphorus to between 0.1 and 0.15 mg/L, reducing the amount of chemical required for removal to very low levels.

Introduction: Removal of phosphorus from the effluent of municipal facilities discharging to the Great Lakes was implemented by the Great Lakes Water Quality Agreement of 1972 between the US and Canadian governments. Most utilities added chemicals to the activated sludge process to precipitate the phosphorus to less than 1 mg/L in the effluent. At this point, biological phosphorus removal was observed but not yet understood. The protection of San Francisco Bay required the removal of nitrogen. The EPA Manual on nitrogen removal (Parker, 1975) showed that 79% of the nitrogen derived from point sources and 11% from dairies and feedlots. Nitrogen was also the limiting nutrient in bays and estuaries on the East Coast and in Florida. In South Africa, the high concentration of population in the relatively dry interior resulted in indirect recycling of wastewater, and even though there had been an ammonia standard in place since 1954, discharges of nitrates and phosphorus had not been reduced. By late 1960s dense growths of blue-green algae resulted in poisoning of animals and taste and odor problems for downstream water users. Windhoek, the capital city of Namibia was running out of reliable water resources. In the late 1960s the National Institute for Water Research in South Africa launched intensive research concentrating especially on reclamation of wastewater for potable re-use. Great strides have been made over the last 30 to 35 years to improve processes for the removal of nitrogen and phosphorus. For standard domestic wastewater effluent phosphorus of less than 0.1 mg/L and nitrogen of less than 3 mg/L can easily be achieved with present technologies. The new challenge to push the limits of treatment to achieve even lower TN and TP has gained momentum and is the focus of many WERF Research projects. Plant owners now realize that a more sophisticated training program for plant operators and managers are essential and that high level instrumentation for monitoring and control would become a high priority as a result of the necessary decrease in safety factors in plant design. Judicious use of chemicals can help greatly in ensuring reliability. Institutions like WEFTEC and IWA are ready for the challenge to educate and inform and WERF is gearing towards making more funds available for cutting edge research to push the limits of technology. The private sector is developing new processes to meet the challenge. There are many tools at our disposal and full use should be made of these. From the regulators side there should be a re-evaluation of methods regulating certain substances, especially recalcitrant compounds that are costly to remove. Overall, there should be a holistic approach and methods of limiting non-point sources should be further researched and evaluated. At some point the cost of taking out finite concentrations of nitrogen and phosphorus must exceed the cost of at least some measures to limit or even treat non-point sources.

Biologically Mediated Transport of Contaminants to Aquatic Systems
Authors: Jules M. Blais, Robie W. Macdonald, Donald Mackay, Eva Webster, Colin Harvey, and John P. Smol
Affiliations: Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada, Department of Fisheries and Oceans, Institute of Ocean Sciences, Sidney, British Columbia, Canada, Canadian Environmental Modelling Centre (CEMC), Trent University, Peterborough, Ontario, Canada, and Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario, Canada
Source: Environmental Science Technology, January 6, 2007, 41(4): 1075 -1084

Abstract: The prevailing view is that long-range transport of semivolatile contaminants is primarily conducted by the physical system (e.g., winds, currents), and biological transport is typically ignored. Although this view may be correct in terms of bulk budgets and fluxes, it neglects the potential of animals to focus contaminants into foodwebs due to their behaviors and lifecycles. In particular, gregarious animals that biomagnify and bioaccumulate certain contaminants and then migrate and congregate can become the predominant pathway for contaminants in many circumstances. Fish and birds provide prominent examples for such behavior. This review examines the potential for biovector transport to expose populations to contaminants. In addition, we apply a modeling approach to compare the potential of biovector transport to other physical transport pathways for a hypothetical lake receiving large numbers of fish. We conclude that biovector transport should not be neglected when considering environmental risks of biomagnifying contaminants.

Calculation Methods to Perform Mass Balances of Micropollutants in Sewage Treatment Plants. Application to Pharmaceutical and Personal Care Products (PPCPs)
Authors: Marta Carballa, Francisco Omil, and Juan M. Lema
Affiliations: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain
Source: Environmental Science Technology, January 3, 2007, 41(3): 884 -890

Abstract: Two different methods are proposed to perform the mass balance calculations of micropollutants in sewage treatment plants (STPs). The first method uses the measured data in both liquid and sludge phase and the second one uses the solid-water distribution coefficient (Kd) to calculate the concentrations in the sludge from those measured in the liquid phase. The proposed methodologies facilitate the identification of the main mechanisms involved in the elimination of micropollutants. Both methods are applied for determining mass balances of selected pharmaceutical and personal care products (PPCPs) and their results are discussed. In that way, the fate of 2 musks (galaxolide and tonalide), 3 pharmaceuticals (ibuprofen, naproxen, and sulfamethoxazole), and 2 natural estrogens (estrone and 17 -estradiol) has been investigated along the different water and sludge treatment units of a STP. Ibuprofen, naproxen, and sulfamethoxazole are biologically degraded in the aeration tank (50-70%), while musks are equally sorbed to the sludge and degraded. In contrast, estrogens are not removed in the STP studied. About 40% of the initial load of pharmaceuticals passes through the plant unaltered, with the fraction associated to sludge lower than 0.5%. In contrast, between 20 and 40% of the initial load of musks leaves the plant associated to solids, with less than 10% present in the final effluent. The results obtained show that the conclusions concerning the efficiency of micropollutants removal in a particular STP may be seriously affected by the calculation method used.

Catchment Microbial Dynamics: The Emergence of a Research Agenda
Authors: D. Kay, A. C. Edwards, R. C. Ferrier, C. Francis, C. Kay, L. Rushby, J. Watkins, M. Wyer, J. Crowther, J. Wilkinson, A. T. McDonald
Affiliations: Hydrology and River Basin Dynamics Research Group, IGES, University of Wales, Aberystwyth SY23 3DB, UK, Earth and Biosphere Institute, University of Leeds, Leeds LS2 9JT, UK, Hydrology and River Basin Dynamics Research Group, IGES, University of Wales, Aberystwyth SY23 3DB, UK
Sources: Progress in Physical Geography, 2007, 31(1): 59-76

Abstract: Parallel policy developments driven in the USA by the Clean Water Act and in Europe by the Water Framework Directive have focused attention on the need for quantitative information on the fluxes of faecal indicator bacteria in catchment systems. Data are required on point and diffuse source loadings, fate and transport of these non-conservative parameters, on the land surface, within soil systems, in groundwater, streams, impoundments and nearshore waters. This new information is needed by regulators to inform Total Maximum Daily Load estimates in the USA and Programmes of Measures in Europe both designed to prevent impairment of water quality at locations where compliance is assessed against health-based standards for drinking, bathing or shellfish harvesting. In the UK, the majority of catchment-scale activity in this field has been undertaken by physical geographers although microbial flux analysis and modelling has received much less attention from the research and policy communities than, for example, the nutrient parameters. This paper charts the policy drivers now operative and assesses the evidence base to support current policy questions. Finally, gaps and priority research questions are identified.

Chemical and Bacterial Quality of Aeration-Type Waste Water Treatment System Discharge
Authors: Panno, Samuel V; Kelly; Hackley; Weibel
Source: Ground Water Monitoring & Remediation, Spring 2007, 27(2): 71-76(6)

Abstract: On-site waste water treatment systems are a potential source of chemical and bacterial contamination to ground water in areas with highly susceptible aquifers such as the sinkhole plain of southwestern Illinois. Ground water from wells, cave streams, and water that discharges from the numerous springs in this area is typically contaminated with nitrate and enteric bacteria and thus may pose a health hazard to those who come into contact with it. In order to determine if the most popular type of on-site waste water treatment systems in the study area was a potential source, samples of effluents discharged at the land surface from 23 domestic aeration-type on-site waste water treatment systems were collected to characterize their water quality and bacterial contents. Most of the effluents contained relatively large concentrations of sodium (Na+), chloride (Cl–), nutrients (nitrogen [N], phosphate [PO43–], and potassium [K+]), and enteric bacteria. Ion concentration ranges (in mg/L) were Na+ (46 to 416), Cl– (21 to 618), N (4.7 to 67), PO4-P (1.4 to 48), and K+ (6.0 to 257). The sources of elevated Na+ and Cl– were human waste and NaCl used in the water softening systems of the houses. Ammonium was usually the dominant inorganic N species, indicating incomplete oxidation of the waste water. Discharge of Na+, Cl–, and nutrients could also have negative impacts on ground water and surface water quality, subsurface and surface aquatic ecosystems, and vegetation. Our characterization of effluent from these waste water treatment systems revealed their generally poor quality and the likelihood that they can contaminate ground water in areas with highly vulnerable aquifers.

Chemolithotrophic Denitrification with Elemental Sulfur for Groundwater Treatment
Authors: Reyes Sierra-Alvarez, Ricardo Beristain-Cardoso, Margarita Salazar, Jorge Gómez, Elias Razo-Flores and Jim A. Field
Affiliations: Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721-0011, USA, Department of Biotechnology, Universidad Autónoma Metropolitana-Iztapalapa, México D.F., México, USA, Division of Environmental Sciences, Institute for Scientific and Technological Research of San Luís Potosí, C.P. 78216, San Luís Potosí, México, USA
Source: Water Research, February 10, 2007, 41(6): 1253-1262

Abstract: Denitrification for the treatment of nitrates in wastewater typically relies on organic electron donating substrates. However, for groundwater treatment, inorganic compounds such as elemental sulfur (S0) are being considered as alternative electron donars in order to overcome concerns that residual organics can cause biofouling. In this study, a packed-bed bioreactor supplied with S0:limestone granules (1:1, v/v) was started up utilizing a chemolithotrophic denitrifying enrichment culture in the form of biofilm granules that was pre-cultivated on thiosulfate. The granular enrichment culture enabled a rapid start-up of the bioreactor. A nearly complete removal of nitrate (7.3 mM) was attained by the bioreactor at nitrate loading rates of up to 21.6 mmol/(Lreactor d). With lower influent concentrations (1.3 mM nitrate) comparable to those found in contaminated groundwater, high nitrate loads of 18.1 mmol/(Lreactor d) were achieved with an average nitrate removal efficiency of 95.9%. The recovery of nitrogen as benign N2 gas was nearly stoichiometric. The concentration of undesirable products from S0-based denitrification such as nitrite and sulfide were low. Comparison of bioreactor results with batch kinetic studies revealed that denitrification rates were dependent on the surface area of the added S0. The surface area normalized denitrification rate was determined to be 26.4 mmol /(m2 S0 d).

Chlorinated Solvents in Groundwater of the United States
Authors: Michael J. Moran,* John S. Zogorski, and Paul J. Squillace
Affiliations: U.S. Geological Survey, 1608 Mountain View Road, Rapid City, South Dakota 57702
Source: Environmental Science and Technology, December 1, 2006, 41 (1): 74 -81, 2007

Abstract: Four chlorinated solvents-methylene chloride, perchloroethene (PCE), 1,1,1-trichloroethane, and trichloroethene (TCE)-were analyzed in samples of groundwater taken throughout the conterminous United States by the U.S. Geological Survey. The samples were collected between 1985 and 2002 from more than 5,000 wells. Of 55 volatile organic compounds (VOCs) analyzed in groundwater samples, solvents were among the most frequently detected. Mixtures of solvents in groundwater were common and may be the result of common usage of solvents or degradation of one solvent to another. Relative to other VOCs with Maximum Contaminant Levels (MCLs), PCE and TCE ranked high in terms of the frequencies of concentrations greater than or near MCLs. The probability of occurrence of solvents in groundwater was associated with dissolved oxygen content of groundwater, sources such as urban land use and population density, and hydraulic properties of the aquifer. The results reinforce the importance of understanding the redox conditions of aquifers and the hydraulic properties of the saturated and vadose zones in determining the intrinsic susceptibility of groundwater to contamination by solvents. The results also reinforce the importance of controlling sources of solvents to groundwater.

Classical Indicators in the 21st Century–Far and Beyond the Coliform
Author: Yates, Marylynn V.
Source: Water Environment Research, March 2007, 79(3): 279-268(8)

Abstract: Indicators have been used for many years to designate the microbiological quality of water. In 1914, the U.S. Public Health Service set a standard that required that drinking water show no evidence of coliform organisms ( U.S. Treasury Department, 1914). Today, almost 100 years later, drinking waters in the United States must meet the standards established in the Total Coliform Rule, which requires that drinking water show no evidence of the presence of total coliform bacteria in 100 mL of water ( U.S. EPA, 1989). However, as limitations with the use of coliforms have become apparent and the applications for indicator microorganisms have expanded, new indicators have been proposed and, in some cases, adopted, for specific purposes, as discussed in detail in a number of recent reports (i.e., National Research Council, 2004; World Health Organization, 2003).

Development of an Integrated Model for Assessing the Impact of Diffuse and Point Source Pollution on Coastal Waters
Authors: D. Yuan, B. Lin R. A., Falconer J. Tao
Affiliations: Department of Mechanics, Tianjin University, Tianjin 300072, China, Cardiff School of Engineering, Cardiff University, The Parade, Cardiff, Wales CF24 3AA, UK, Department of Mechanics, Tianjin University, Tianjin 300072, China
Source: Environmental Modeling & Software, June 2007, 22(6): 871-879

Abstract: Pollution loads from land sources and their impact on the receiving waters can be predicted by using land-use and surface water quality models, respectively. In this paper details are given of the development of an integrated modelling system for managing water quality in coastal basins. The system includes a model linking the pollution input loads to land-use and a model for simulating surface flow and chemical and biological processes. The land-use model consists of two main components: a database and a model base. It uses a GIS system, namely ArcGIS, as the model platform. The database, built in the Geo-database format, includes six data sets containing information on social, economical, bathymetrical and hydrological aspects of a study area. The model base includes a series of transfer functions that link the pollution loads to key sources, including those from: industrial, domestic and agricultural inputs, and fish and animal farming. The water quality model is a numerical model which solves the governing equations representing the physical, chemical and biological processes in coastal waters. The modelling system was set up for Bohai Bay in China, with the land-use model being used to provide nutrient loadings from individual inputs and the water quality model used to predict the impact of these inputs on the receiving waters. Model simulations were also undertaken to predict the water quality conditions for various development and management scenarios.

Discharge of Escherichia Coli from Agricultural Surface and Subsurface Drainage Water: Tillage Effects
Authors: A. Thiagarajan¹, R. Gordon¹, A. Madani¹ and G. W. Stratton²
Affiliations: Department of Engineering, Nova Scotia Agricultural College, Truro, Nova Scotia, Canada, B2N 5E3, Deparment of Environmental Sciences, Nova Scotia Agricultural College, Truro, Nova Scotia, Canada, B2N 5E3
Source: Water, Air & Soil Pollution, June 2007, 182(1-4):3-12

Abstract: Drainage water from agricultural fields with applied manure can degrade the bacterial quality of surface and groundwater. The impact of conventional tillage (CT) and zero tillage (ZT) practices on Escherichia coli (E.coli) discharge through artificially drained soils is not well understood. Consequently, two field trials were conducted during 2002–2004. The first trial involved fall applications of beef manure while the second involved spring applications of dairy manure. Both surface and subsurface drainage water were monitored in the first trial while only subsurface drainage water was monitored in the second. Under fall applied beef manure (trial 1), no differences (p›0.05) were observed in E.coli concentrations (cfu/100 ml) in combined drainage water under both tillage systems. However, during 2003–2004, subsurface drainage water under ZT had higher E.coli concentrations and loads than drainage water under CT. When the combined (surface + subsurface) annual E.coli loads were considered, CT loads were greater than ZT during 2002–2003 with an opposite situation during 2003–2004. Overall, annual E.coli loads were similar under ZT (4.7×1010 cfu/ha) and CT (4.8×1010 cfu/ha). Spring dairy manure application (trial 2) produced significant (p›0.03) tillage effect on E.coli loads in subsurface drainage water only during the second year. During the study period, ZT plots (1.55×1010 cfu/ha) discharged 5× more E.coli than CT (0.23×1010 cfu/ha). A longer duration of ZT practices resulted in higher subsurface flow volumes and subsequently greater loads of E.coli discharge in both trials.

An Eco-Balance Approach to the Evaluation of Historical Changes in Nitrogen Loads at a Regional Scale
Authors: Sonoko D. Kimura^a, and Ryusuke Hatano^b
Affiliations: aGraduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 183-8588, Japan, bGraduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
Source: Agricultural Systems, May 2007, 94(2):165-176

Abstract: Historical changes in nitrogen flows of a municipality from 1912 to 2002 were analyzed to evaluate the relation between production and environmental pollution. The system comprised human, livestock and farmland subsystems. The indicators used in this study were production, surplus nitrogen (N) on farmland and total systems, and flow indices. Flow indices consist of cycling index (CI), export index (EI), and loss index (LI). CI was defined as the proportion of nitrogen cycled in the system to the total system throughflow, EI as nitrogen exported from the system, and LI as nitrogen lost from the system (sum of field surplus nitrogen, nitrogen in non-utilized excreta, and N2O and NH3 emissions).

Complex changes in N flow of human, livestock, and farmland subsystems were analyzed by comparing production to the surplus N on farmland and total systems and flow indices. The relations between production and other indicators were defined as eco-balance. A negative correlation is desirable between the indicators and production in the case of an indicator for environmental damage such as surplus N and LI, whereas a positive correlation is preferred in the case of benefits such as CI and EI.

Flow indices simplified the complex changes inside the system. According to the analysis of eco-balance, the investigated period from 1912 to 2002 could be divided into three periods: manure-based period (MBP) from 1912 to 1957, transition period from manure-based to chemical-fertilizer-based period (TP) from 1958 to 1977, and chemical-fertilizer-based period (CBP) from 1978 to 2002. Driving forces of each period were extracted based on the eco-balance.

Effect of Ammonia Nitrogen and Dissolved Organic Matter Fractions on the Genotoxicity of Wastewater Effluent during Chlorine Disinfection
Authors: Li-Sha Wang, Hong-Ying Hu, and Chao Wang
Affiliations: Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, PR China
Source: Environmental Science and Technology, November 18, 2006, 41 (1): 160 -165, 2007

Abstract: Chlorine is a widely used disinfectant which prevents the spread of harmful pathogens when reusing wastewater, but harmful byproducts might be formed and cause adverse ecological and health effects. In this study, the potential effects of chlorination on the genotoxicity of different biologically treated wastewater samples were investigated using the umu test. For the first time, ammonia nitrogen (NH3-N) was found to significantly influence genotoxicity during wastewater chlorination. After chlorination, the genotoxicity decreased in wastewater with a low NH3-N concentration (‹10~20 mg/L), but it increased notably in wastewater with a high NH3-N concentration (›10~20 mg/L). By fractionating the DOM (dissolved organic matter) in wastewater into different fractions, it was found that the hydrophilic substances (HIS) fraction of DOM was the key fraction involved in decreasing genotoxicity during the chlorination of wastewater with a low NH3-N concentration, while the hydrophobic acids (HOA) fraction of DOM was the key fraction involved in increasing genotoxicity during chlorination of wastewater with a high NH3-N concentration. Furthermore, fluorescence spectroscopy analysis on different fractions indicated that some free or combined aromatic amino acids might produce highly genotoxic byproducts during the chlorination of wastewater with a high NH3-N content, and this was then demonstrated through experiments on the chlorination of free aromatic amino acids.

Efficacy of Bacteroides Measurements for Reducing the Statistical Uncertainty Associated with Hydrologic Flow and Fecal Loads in a Mixed Use Watershed
Authors: Randall W. Gentry^a,d,*, Alice C. Layton^d, Larry D. McKay^c, John F. McCarthy^c,d, Dan E. Williams^d, Shesh R. Koirala^b and Gary S. Sayler^d
Affiliations: a Inst. for a Secure and Sustainable Environment, The Univ. of Tennessee, 311 Conference Center Building, Knoxville, TN 37996-4134, b Civil & Environmental Engineering, The Univ. of Tennessee, 62 Perkins Hall, Knoxville, TN 37996-2010, c Dep. of Earth and Planetary Sciences, The Univ. of Tennessee, Knoxville, TN 37996, d Center for Environmental Biotechnology, The Univ. of Tennessee, Knoxville, TN 37996
Source: Journal of Environmental Quality, 17 July 2007, 36:1324-1330

Abstract: This paper presents an analysis of the occurrence and uncertainty of source-specific Bacteroides and Escherichia coli in a stream in a mixed land-use watershed with human, cattle, and wildlife fecal inputs located in a karstic geologic region during baseflow conditions. The objectives of the study were to evaluate the occurrence, hydrologic significance, and source of fecal mass in the stream using assays for total Bacteroides (AllBac) and bovine-specific Bacteroides (BoBac), and then to compare these measurements with E. coli densities and loads. Samples were collected during baseflow conditions over several months at seven different main channel sites in the Stock Creek watershed, a 49.3 km2 basin located in Knoxville, TN (USA). We determined instantaneous loads for total fecal loads, bovine fecal loads, and E. coli from measured flow rates and the representative Bacteroides fecal masses and/or E. coli densities. The study indicated a strong correlation between total fecal load (kg d–1), bovine fecal load (kg d–1), E. coli load rate (CFU d–1), 7-d antecedent precipitation, and turbidity. The various datasets were used to establish parameter correlations and spatial dependencies throughout the watershed. The data analysis demonstrated two prevalent patterns throughout the watershed: (i) a runoff-dominated transport and occurrence; and (ii) potential groundwater-dominated transport and occurrence.

Escherichia coli has Multiple Enzymes that Attack TNT and Release Nitrogen for Growth
Authors: González-Pérez, M. Mar; van Dillewijn, Pieter; Wittich, Rolf-M.; Ramos, Juan L.
Source: Environmental Microbiology, June 2007, 9(6): 1535-1540(6)

Abstract: There has been a growing interest in the degradation of 2,4,6-trinitrotoluene (TNT) over the last decade, ever since its removal from polluted sites was declared an international environmental priority. Certain aerobic and anaerobic microorganisms are capable of using TNT as an N source, although very few studies have proven the mineralization of this compound. An unexpected observation in our laboratory led us to discover that certain Escherichia coli bench laboratory strains have multiple enzymes that attack TNT. One of the NemA products is responsible for the release of nitrite from the nitroaromatic ring: among the metabolites observed in vitro include Meisenheimer dihydride complexes of TNT from which 2-hydroxylamino-6-nitrotoluene is slowly formed during their rearomatization under concomitant release of nitrite. Furthermore, NemA, together with NfsA and NfsB reduce the nitro groups on the aromatic ring to the corresponding hydroxylamino derivatives, which probably results in the release of ammonium ions which can, in turn be used as a nitrogen source by E.coli for growth.

Evaluation of Enrichment-Free PCR-Based Detection on the Rfbe Gene of Escherichia Coli O157–Application to Municipal Wastewater
Authors: Romain Bertrand and Benoit Roig
Affiliations: Biodiagnostic Department, Ecole des Mines d’Alés, Centre LGEI, 6 Avenue de Clavières, 30319 Ales, France, JE2479, Centre Universitaire de Nîmes, rue du Dr G. Salan, 30021 Nîmes Cedex 1, France
Source: Water Research, January 12, 2007, 41(6): 1280-1286

Abstract: Escherichia coli O157 strains have emerged as important human enteric pathogens. Strains that express the O-antigen 157 are commonly associated with severe clinical manifestations, including bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. E. coli O157 strains may be transmitted in a variety of ways, including food, water and person-to-person or animal-to-person contact. Fecal contamination is one source of environmental contamination and is responsible for the presence of these pathogens in the environment. We used a specific and sensitive PCR assay based on the rfbE gene to detect low levels of these pathogens in wastewater. The set of primers used was designed to amplify an intragenic segment of the rfbE gene. The amplification assay detected 200 CFU of E. coli O157 in pure water. The prevalence of E. coli O157 in the effluents of 44 wastewater treatment plants was determined (7%).

Evaluation of Landscape and Instream Modeling To Predict Watershed Nutrient Yields Environmental Modeling & Software
Authors: K. W. Migliaccio, I. Chaubey, B. E. Haggard
Affiliations: University of Florida Tropical Research and Education Center, Agricultural and Biological Engineering Department, 18905 SW 280 Street, Homestead, FL 33031, United States, University of Arkansas, 203 Engineering Hall, Fayetteville, AR 72701, United States
Source: Elsevier Science Publishers B. V., July 2007, 22(7): 987-999

Abstract: The project goal was to loosely couple the SWAT model and the QUAL2E model and compare their combined ability to predict total phosphorus (TP) and NO”3-N plus NO”2-N yields to the ability of the SWAT model with its completely coupled water quality components to predict TP and NO”3-N plus NO”2-N yields from War Eagle Creek watershed in Northwest Arkansas. Model predictions were compared using a statistical approach to identify significant differences between the two modeling methods. Results from two variations of the Pearson product-moment correlation (p‹0.05) indicated that correlation coefficients and regression slopes for the two data sets were not significantly different. This implies that neither modeling method was significantly better in predicting monthly TP and NO”3-N plus NO”2-N yields from the watershed. Additionally, no significant differences were present between predicted outputs of the SWAT model with instream components active compared with when instream components were inactive, indicating a need for further testing and refinement of the SWAT algorithms simulating instream processes. We can further infer that the instream processes available in SWAT may not be enhancing its predictive abilities as far as simulating instream components.

Exploring the Ecological Status of Human Altered Streams through Generative Topographic Mapping
Authors: A. Vellido, E. Martí, J. Comas, I. Rodríguez-Roda, F. Sabater
Affiliations: Department of Computing Languages and Systems (LSI), Polytechnic University of Catalonia (UPC ), C. Jordi Girona, 1-3, 08034 Barcelona, Spain, Centre d'Estudis Avançats de Blanes-CSIC, Accés a la Cala de St. Francesc, 14, 17300 Blanes, Girona, Spain, Chemical and Environmental Engineering Laboratory (LEQUIA), University of Girona, Campus Montilivi s/n, 17071 Girona, Spain , Department of Ecology, University of Barcelona (UB), C. Diagonal, 645, 08028 Barcelona, Spain
Source: Environmental Modelling & Software, July 2007, 22(7): 1053-1065

Abstract: The STREAMES (STream REAch Management, an Expert System) European project is an international enterprise for the development of a knowledge-based environmental decision support system to assist water managers with their decision making tasks. It involves the evaluation of the effect of substantial nutrient loads on the overall water quality and ecological status of stream ecosystems. Empirical data for the knowledge base come from several streams located throughout Europe and Israel, with emphasis on streams from the Mediterranean region. These data comprise several types of variables, including physical, chemical and biological parameters. The complexity of the data limits the amount and completeness of the available information. This study explores how similar the selected streams are on the basis of the ecological descriptors measured. The analysis of these similarities helps us to ascertain whether the same model of ecological status might hold over the variety of streams under consideration. The available data are explored and analysed through reconstruction, visualization and clustering using the Generative Topographic Mapping (GTM), a neural network-based model. Amongst the many advantages of the probabilistic setting of GTM, one is especially relevant to the problem at hand: its ability to handle and reconstruct missing data in a principled way.

Ground Cover Impacts On Nitrogen Export From Manured Riparian Buffers
Authors: Butler, D.M., Ranells, N, Franklin, Dorcas - dory, Poore, M, Green, JR., J
Affiliations: University Of Georgia, NC State University
Source: Journal of Environmental Quality, January 10, 2007, 36:155-162

Abstract: Maintaining ground cover of forages may reduce the export of nitrogen (N) from pastures. The objective of this work was to determine the effect of ground cover on N export from pastured riparian areas that received simulated rainfall. Plots were established on two adjacent sites in the North Carolina Piedmont: one of 10% slope with Appling sandy loam soils and a second of 20% slope with Wedowee sandy loam soils. Both sites had existing mixed tall fescue (Festuca arundinacea Schreb.) and dallisgrass (Paspalum dilatatum Poir.) vegetation. Existing forage stands were modified to represent a range of cover levels by establishing 4 cover treatments: a) 100% bare soil area (bare ground), b) 55% bare soil area with 45% ground cover (low cover), c) 30% bare soil area with 70% ground cover (medium cover), and d) not altering full vegetative cover plots (high cover). For all rain events combined, mean nitrate-N export was greatest from bare ground and was reduced by 34% at low cover, which did not differ from high cover. Mean ammonium-N export was slightly elevated (~1.37 kg N ha-1) in months when manures were applied and negligible (‹ 0.02 kg N ha-1) in all other months. For all rain events combined, mean export of total N was greatest from bare ground and was reduced by at least 85% at all other cover levels. Results indicated that cover and time of rainfall following grazing are important determinants of the overall impact of riparian grazing.

Hydrologic Flow Controls on Biologic Iron(III) Reduction in Natural Sediments
Authors: Morgan L. Minyard and William D. Burgos
Affiliations: Department of Civil and Environmental Engineering, The Pennsylvania State University, 212 Sackett Building, University Park, Pennsylvania 16802-1408
Source: Environmental Science Technology, January 4, 2007, 41(4); 1218 -1224

Abstract: Bacterial reduction of a hematite-rich natural coastal sand was studied in flow-through column reactors at flow rates which varied from 0.62 to 11 pore volumes d-1. Sand columns were wet-packed with the dissimilatory metal-reducing bacterium (DMRB) Shewanella putrefaciens CN32, and a PIPES-buffered, lactate-containing growth medium was pumped through the columns for over 20 days. Soluble Fe(II), acetate and lactate concentrations measured in the column effluents showed that steady-state conditions were established after a few days with every flow rate. The steady-state effluent Fe(II) concentration was directly controlled by the flow rate where [Fe(II)]ss decreased as the flow rate increased. Increased flow rate increased biologic activity based on the steady-state flux of soluble Fe(II) and total Fe(II) production (included Fe(II) extracted from sand at the conclusion of the experiment), decreased the fraction of lactate oxidized for energy that likely increased cell synthesis, and decreased the concentration of sorbed Fe(II) that, in turn, decreased the relative percentage of Fe(II) retained by the column materials. Increased biologic activity was likely promoted by greater reactant delivery (i.e., lactate, N, P) and greater advective removal of Fe(II). These results demonstrate that biologic Fe(III) reduction, cell growth, and abiotic Fe(II) sorption are all coupled to the hydrologic flow rate.

Hydrology and Nutrient Biogeochemistry in a Created River Diversion Oxbow Wetland
Authors: Daniel F. Fink^a, and William J. Mitsch^a
Affiliaitons: ^aWilma H. Schiermeier Olentangy River Wetland Research Park, Environmental Science Graduate Program and School of Environment and Natural Resources, 352 W. Dodridge Street, The Ohio State University, Columbus, OH 43202, USA
Source: Ecological Engineering, 1 June 2007, 30(2):93-102

Abstract: A better understanding of the function of riparian wetlands is needed. In this study, hydrological, successional, and water-quality dynamics are documented for a whole-ecosystem study involving a 3-ha created riparian wetland at the Schiermeier Olentangy River Wetland Research Park at The Ohio State University in Columbus, Ohio, USA, during 2003 and 2004. This wetland typically receives seven or eight natural weeklong flood pulses each year from the Olentangy River. Of 21 species planted in 1997, only Scirpus americanus and Juncus effusus remained as important macrophyte species during the study 6–7 years after planting. Typha spp., a naturally colonizing species, was the dominant macrophyte in most of the wetland. Mean retention rates per flood pulse for nitrate-nitrite, total Kjeldahl nitrogen (TKN), soluble reactive phosphorus (SRP), and total phosphorus (TP) were 0.71 g-N m–2, 0.92 g-N m–2, 0.016 g-P m–2, and 0.08 g-P m–2, respectively. The annual reductions of N-NO3–, TN, P-SRP, and TP were 74%, 41%, 46%, and 31% by mass. A greater attenuation of NO3– and TP occurred in the emergent marsh section of the wetland than the open water section. Conversely TKN increased through the emergent marsh and decreased through the open water section. Overall, the oxbow design is successful in ecological terms and we recommend that similar diversion wetlands be created in other locations to examine their function under different climatic and hydrological conditions.

Identifying Fecal Sources in a Selected Catchment Reach Using Multiple Source-Tracking Tools
Authors: Jason R. Vogel, Donald M. Stoeckel, Regina Lamendella, Ronald B. Zelt, Jorge W. Santo Domingo, Steven R. Walker and Daniel B. Oerther
Affiliations: USGS, 5231 S. 19th St., Lincoln, NE 68512, USGS, 6480 Doubletree Ave., Columbus, OH 43229, Dep. of Environmental Engineering, Univ. of Cincinnati, Cincinnati, OH 45220, USEPA Office of Research and Development, National Risk Management Research Lab., 26 Martin Luther King Dr., MS-387, Cincinnati, OH 45268, Nebraska Dep. of Environmental Quality, 1200 “N” St., Suite 400, P.O. Box 98922, Lincoln, NE 68509
Source: Journal of Environmental Quality, April 5, 2007, 36:718-729

Abstract: Given known limitations of current microbial source-tracking (MST) tools, emphasis on small, simple study areas may enhance interpretations of fecal contamination sources in streams. In this study, three MST tools–Escherichia coli repetitive element polymerase chain reaction (rep-PCR), coliphage typing, and Bacteroidales 16S rDNA host-associated markers–were evaluated in a selected reach of Plum Creek in south-central Nebraska. Water-quality samples were collected from six sites. One reach was selected for MST evaluation based on observed patterns of E. coli contamination. Despite high E. coli concentrations, coliphages were detected only once among water samples, precluding their use as a MST tool in this setting. Rep-PCR classification of E. coli isolates from both water and sediment samples supported the hypothesis that cattle and wildlife were dominant sources of fecal contamination, with minor contributions by horses and humans. Conversely, neither ruminant nor human sources were detected by Bacteroidales markers in most water samples. In bed sediment, ruminant- and human-associated Bacteroidales markers were detected throughout the interval from 0 to 0.3 m, with detections independent of E. coli concentrations in the sediment. Although results by E. coli-based and Bacteroidales-based MST methods led to similar interpretations, detection of Bacteroidales markers in sediment more commonly than in water indicates that different tools to track fecal contamination (in this case, tools based on Bacteroidales DNA and E. coli isolates) may have varying relevance to the more specific goal of tracking the sources of E. coli in watersheds. This is the first report of simultaneous, toolbox approach application of a library-based and marker-based MST analyses to flowing surface water.

Identifying Fecal Sources in a Selected Catchment Reach Using Multiple Source-Tracking Tools
Authors: Susan Searles Nielsen, Beth A Mueller and Carrie M Kuehn
Affiliations: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA, Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Seattle, WA, USA, Amgen Inc., Global Epidemiology, Thousand Oaks, CA, USA
Source: Journal of Exposure Science and Environmental Epidemiology, April 4, 2007

Abstract: Consumption of nitrate and nitrite is associated with a variety of health outcomes. Commercially available test strips that allow semi-quantitative estimation of these contaminants in drinking water are inexpensive relative to laboratory testing, and are simple to use. To examine the accuracy of a nitrate/nitrite test strip, we recruited Washington State residents to estimate levels of these contaminants in their tap water using these strips, and simultaneously provide a tap water sample for laboratory analysis. Paired results were available from 102 homes. On the basis of laboratory assay, nitrate levels as nitrogen ranged from no nitrate (27%) to 40.5 mg/l (median 0.4 mg/l). Spearman's correlation coefficient between test strip- and laboratory-measured nitrate indicated moderate precision overall (r=0.72). Correlation was similar for homes inside and outside city/town limits, but differed by primary source of water for the purveyor indicated by residents (r=0.72 for groundwater and r=0.34 for surface water). Seven (7%) participants reported difficulty in distinguishing colors (contaminant levels) when using the test strip; and among the samples with nitrate, the laboratory assay indicated higher nitrate levels than the test strip for 81%. Nitrite was not detected by laboratory assay; in comparison, five (5%) subjects reported any nitrite according to the test strip. Nitrate/nitrite test strips may be useful in some epidemiologic studies, but should be used with caution, preferably as a screening tool or when laboratory assays are not feasible.

The Impact of Nutrient Loading From Canada Geese (Branta Canadensis) on Water Quality, a Mesocosm Approach
Authors: Robert L. Unckless^{1, 2} and Joseph C. Makarewicz¹
Affiliations: Department of Environmental Science and Biology, State University of New York College, Brockport, NY 14420, USA
Source: Hydrobiologia, 27 April 2007, 586 (1):1573-5117

Abstract: A mesocosm experiment determined the impact of Canada Goose (Branta canadensis) feces on water chemistry. After 30 days of fecal additions (treatments of 1.209, 2.419 g, and 12.090 g every 3 d to 0.811 m3 size mescosms), no significant changes in water column total phosphorus, nitrate, N:P ratios, total Kjeldahl nitrogen, chlorophyll-a, or phycocyanin were observed among treatment groups. Soluble reactive phosphorus showed a marginally significant increase in the high treatment group. A settling experiment suggested that goose feces and associated nutrients settled quickly to the sediment. Since fecal material settles quickly to the sediment, the impact of additional fecal material would not become evident in a lake until a wind event mixes the sediment into the water column or through alteration of the productivity or community structure of the benthos.

Impact of a Trout Farm on the Water Quality of an Apennine Creek from Daily Budgets of Nutrients
Authors: Marco Bartoli ^a; Daniele Nizzoli ^a; Daniele Longhi ^a; Alex Laini ^a; Pierluigi Viaroli ^a
Affiliations: ^a Dipartimento di Scienze Ambientali, Università degli Studi di Parma. Parma. Italy
Source: Chemistry and Ecology, February 2007, 23(1): 1 - 11

Abstract: A detailed 24-h investigation in August 2005 evaluated net dissolved and particulate nutrient budgets in a small trout farm located in the Parma Apennines. During the monitoring period, due to water shortage, the Cedra Creek was almost entirely diverted into the farm; the water flow was 190 l s-1, and the fish standing stock about 20 t. Inflow and outflow waters were characterized for dissolved gases (O2 and CO2) and dissolved and particulate inorganic nutrients ( , , , , PN, and PP). Solute concentrations in outflowing waters were found to fluctuate considerably during the day, due to fish metabolic activity and farm-management practices. Despite the small amount of feed supplied to the fish (75 kg d-1) due to high water temperatures ( 20 °C) and the high feed conversion factor ( 1.2), the farm released net amounts of 2.20 and 0.76 kg d-1 of nitrogen and phosphorus, respectively, to the Cedra Creek. Of the nutrients produced, 68% of the nitrogen was as , while 67% of the phosphorus was particulate. Significantly different , , and PP concentrations were measured 500 m downstream of the fish farm compared with inflowing water. This study supports the hypothesis that the ecological quality of creeks or streams receiving fish farm effluents can be seriously affected due to fine particle sedimentation, interstice clogging, simplification of benthic macrofauna communities, and stimulation of microfitobenthos growth.

Influencing Factors and a Proposed Evaluation Methodology for Predicting Groundwater Contamination Potential from Stormwater Infiltration Activities
Authors: Clark, Shirley E; Pitt, Robert
Source: Water Environment Research, January 2007, 79(1): 229-36(8)

Abstract: To offset the detrimental effects of urbanization on groundwater recharge, stormwater managers are focusing on infiltrating much of the runoff from a site that was generated because of development. For this to be effective, tools are required to predict the potential for contamination resulting from this infiltration for many site conditions, because infiltration should be stressed in areas where the least potential for causing groundwater contamination exists. Factors that influence contamination potential include the pollutant concentration in the runoff directed to the infiltration device and the ability of the underlying soil to remove the pollutant. The groundwater contamination potential of some pollutants, even those with high concentrations and moderate-to-high mobilities, can be reduced with proper pretreatment before infiltration. This paper presents a methodology that can be used to evaluate infiltration as an management option and introduces two different levels of models that could be used to evaluate contamination potential.

Integrated Approach for Microbiological Impact Assessment of Public Wastewater Treatment Plants
Authors: Marco Ostoich, Emilia Aimo, Rita Frate, Marina Vazzoler, Silvia Stradella, Paolo Osti
Affiliations: Inland Waters Observatory, Provincial Department of Padua, ARPAV (Veneto Regional Prevention and Protection Agency). Padua, (PD). Italy, Venice Provincial Department, ARPAV. Mestre, (VE). Italy, Northern Adriatic Sea Observatory, ARPAV. Padua, (PD). Italy, Environmental Policies Dep., Province of Venice. Mestre, (VE). Italy
Source: Chemistry and Ecology, February 2007, 23(1): 43-62

Abstract: Wastewaters are a source of pathogenic micro-organisms in the environment. The microbial load and residues found in the final effluents of wastewater-treatment plants (WWTPs) depend on the WWTPs' abatement capacity and the final disinfection treatment systems applied to wastewaters before discharge into water. A historical database with data on surface and marine-coastal water quality and on the characterization of WWTP effluents was made using data from 1997 to 2004 to assess the microbiologic impact along the coast of the Venice province (Italy, northern Adriatic sea). The monitoring of river and sea discharges along the coast is integrated with the application of the Synthetic Pluriennal Faecalization Index (ISPF). The experimental study was conducted in the period from November 2002 to April 2004 by the Veneto Regional Environmental Prevention and Protection Agency. The results of this investigation on faecal contamination together with previous data are presented with a preliminary performance characterization of the WWTPs' disinfection technologies (sodium hypochlorite, peracetic acid, UV rays, and ozone).

Intra-individual Variability in Toenail Arsenic Concentrations in a Michigan Population, USA
Authors: Melissa J Slotnick, Jaymie R Meliker and Jerome O Nriagu
Affiliations: Department of Environmental Health Sciences, School of Public Health, The University of Michigan, 109 Observatory St., Ann Arbor, Michigan 48109, USA, Department of Environmental Health Sciences, School of Public Health, The University of Michigan, Ann Arbor, Michigan, USA, BioMedware Inc., Ann Arbor, Michigan, USA
Source: Journal of Environmental Quality, April 11, 2007, 36: 464-468

Abstract: Arsenic concentration in toenail clippings is used as a biomarker of exposure in epidemiological studies, often under the assumption that a single measurement represents long-term exposure. For this assumption to hold, the measured arsenic concentrations must be stable over time, yet temporal variability has not been adequately assessed. This study aims to evaluate temporal variability in multiple toenail samples collected from a population exposed to drinking water arsenic levels ‹100 g/l. Our objectives are to investigate factors responsible for biomarker variability and to assess the suitability of single versus multiple measurements for determining exposure in epidemiological studies. Multiple toenail and drinking water samples were collected from 254 participants enrolled in a case–control study of arsenic exposure and bladder cancer in Michigan, USA; participants also answered questions on water consumption. Toenail samples collected an average of 14 months apart were positively correlated, although a substantial amount of variability was detected (r=0.43, P‹0.0001, n=236). Arsenic concentration in drinking water was stable and small changes in drinking water arsenic concentration did not explain variability in toenail arsenic concentration. Change in drinking water consumption, however, was significant in predicting differences in toenail arsenic concentration. Stronger correlations between drinking water arsenic concentration and intake and toenail arsenic concentration were observed when two toenail samples were averaged, suggesting that multiple measurements may more accurately reflect exposure. When exposure was categorized into tertiles and other pre-determined categories, 25–40% of exposures were differentially classified. Only a small percentage (‹4%), however, were classified as having low exposure using a single measurement and high exposure when an average of two measurements was used. These results suggest that the use of multiple measurements is unlikely to affect exposure classification of individuals into high- or low-exposure groups; however, collection of multiple samples may be advantageous for more refined exposure classification.

Linking Ecological Theory with Stream Restoration
Authors: Lake, P. S.; Bond, N.; Reich, P.
Source: Freshwater Biology, April 2007, 52(4): 597-615(19)

Abstract:
1. Faced with widespread degradation of riverine ecosystems, stream restoration has greatly increased. Such restoration is rarely planned and executed with inputs from ecological theory. In this paper, we seek to identify principles from ecological theory that have been, or could be, used to guide stream restoration.
2. In attempts to re-establish populations, knowledge of the species' life history, habitat template and spatio-temporal scope is critical. In many cases dispersal will be a critical process in maintaining viable populations at the landscape scale, and special attention should be given to the unique geometry of stream systems
3. One way by which organisms survive natural disturbances is by the use of refugia, many forms of which may have been lost with degradation. Restoring refugia may therefore be critical to survival of target populations, particularly in facilitating resilience to ongoing anthropogenic disturbance regimes.
4. Restoring connectivity, especially longitudinal connectivity, has been a major restoration goal. In restoring lateral connectivity there has been an increasing awareness of the riparian zone as a critical transition zone between streams and their catchments.
5. Increased knowledge of food web structure - bottom-up versus top-down control, trophic cascades and subsidies - are yet to be applied to stream restoration efforts.
6. In restoration, species are drawn from the regional species pool. Having overcome dispersal and environmental constraints (filters), species persistence may be governed by local internal dynamics, which are referred to as assembly rules.
7. While restoration projects often define goals and endpoints, the succession pathways and mechanisms (e.g. facilitation) by which these may be achieved are rarely considered. This occurs in spite of a large of body of general theory on which to draw.
8. Stream restoration has neglected ecosystem processes. The concept that increasing biodiversity increases ecosystem functioning is very relevant to stream restoration. Whether biodiversity affects ecosystem processes, such as decomposition, in streams is equivocal.
9. Considering the spatial scale of restoration projects is critical to success. Success is more likely with large-scale projects, but they will often be infeasible in terms of the available resources and conflicts of interest. Small-scale restoration may remedy specific problems. In general, restoration should occur at the appropriate spatial scale such that restoration is not reversed by the prevailing disturbance regime.
10. The effectiveness and predictability of stream ecosystem restoration will improve with an increased understanding of the processes by which ecosystems develop and are maintained. Ideas from general ecological theory can clearly be better incorporated into stream restoration projects. This will provide a twofold benefit in providing an opportunity both to improve restoration outcomes and to test ecological theory.

Long-Term Phosphorus Immobilization by a Drinking Water Treatment Residual
Authors: Sampson Agyin-Birikorang, George A. O'Connor, Lee W. Jacobs, Konstantinos C. Makris and Scott R. Brinton
Affiliations: Soil and Water Sci. Dep., Univ. Florida, Gainesville, FL 32611-0510 Dep. Crop and Soil Sci., Mich. State Univ., East Lansing, MI 48824 Earth and Environmental Sci. Dep., Univ. Texas, San Antonio, 6900 N. Loop, San Antonio, TX 78249-0663
Source: Journal of Environmental Quality, January 9, 2007, 36: 316-323

Abstract: Received for publication April 24, 2006. Excessive soluble P in runoff is a common cause of eutrophication in fresh waters. Evidence indicates that drinking water treatment residuals (WTRs) can reduce soluble P concentrations in P-impacted soils in the short term (days to weeks). The long-term (years) stability of WTR-immobilized P has been inferred, but validating field data are scarce. This research was undertaken at two Michigan field sites with a history of heavy manure applications to study the longevity of alum-based WTR (Al-WTR) effects on P solubility over time (7.5 yr). At both sites, amendment with Al-WTR reduced water-soluble P (WSP) concentration by 60% as compared to the control plots, and the Al-WTR-immobilized P (WTR-P) remained stable 7.5 yr after Al-WTR application. Rainfall simulation techniques were utilized to investigate P losses in runoff and leachate from surface soils of the field sites at 7.5 yr after Al-WTR application. At both sites, amendment with Al-WTR reduced dissolved P and bioavailable P (BAP) by ›50% as compared to the control plots, showing that WTR-immobilized P remained nonlabile even 7.5 yr after Al-WTR amendment. Thus, WTR-immobilized P would not be expected to dissolve into runoff and leachate to contaminate surface waters or groundwater. Even if WTR-P is lost via erosion to surface waters, the bioavailability of the immobilized P should be minimal and should have negligible effects on water quality. However, if the WTR particles are destroyed by extreme conditions, P loss to water could pose a eutrophication risk.

Luminex Detection of Fecal Indicators in River Samples, Marine Recreational Water, and Beach Sand
Authors: Baums IB, Goodwin KD, Kiesling T, Wanless D, Diaz MR, Fell JW
Affiliations: Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA.
Source: Marine Pollution Bulletin, May 2007, 54(5): 521-536

Abstract: Research to understand and remediate coastal pollution is moving toward a multitiered approach in which traditional enumeration of fecal indicators is accompanied by molecular analysis of a variety of targets. Technology that rapidly detects multiple microbial contaminants would benefit from such an approach. The Luminex((R)) 100trade mark system is a suspension array that assays multiple analytes rapidly in a single well of a microtiter plate. The ability of the system to simultaneously detect multiple fecal indicating bacteria in environmental samples was tested. Primer/probe sets were designed to simultaneously detect the following fecal indicators: the Bacteroides fragilis group, Enterococcus spp., Escherichia coli and Shigella spp., Bacteroides distasonis, and Ent. faecalis. Specificity and sensitivity of the Luminex probes was tested against laboratory cultures. In addition, sequencing, culture plate testing, and specificity testing with environmental isolates were steps taken to validate the function of the assay with environmental samples. Luminex response to cultures and to environmental samples was consistent with sequencing results, suggesting that the technology has the potential to simultaneously detect multiple targets for coastal water quality applications, particularly as progress is made to efficiently extract DNA from water.

Massive Microbiological Groundwater Contamination Associated with a Waterborne Outbreak in Lake Erie, South Bass Island, Ohio
Author(s): Theng-Theng Fong, Linda S. Mansfield, David L. Wilson, David J. Schwab, Stephanie L. Molloy and Joan B. Rose
Source: Environmental Health Perspectives, Vol. 115, No. 6 (Jun., 2007), pp. 856-864
Publisher: The National Institute of Environmental Health Sciences (NIEHS)
Stable URL: http://www.jstor.org/stable/4139303

ABSTRACT: Background: A groundwater-associated outbreak affected approximately 1,450 residents and visitors of South Bass Island, Ohio, between July and September 2004. Objectives: To examine the microbiological quality of groundwater wells located on South Bass Island, we sampled 16 wells that provide potable water to public water systems 15-21 September 2004. Methods: We tested groundwater wells for fecal indicators, enteric viruses and bacteria, and protozoa (Cryptosporidium and Giardia). The hydrodynamics of Lake Erie were examined to explore the possible surface water-groundwater interactions. Results: All wells were positive for both total coliform and Escherichia coli. Seven wells tested positive for enterococci and Arcobacter (an emerging bacterial pathogen), and F-specific coliphage was present in four wells. Three wells were positive for all three bacterial indicators, coliphages, and Arcobacter, adenovirus DNA was recovered from two of these wells. We found a cluster of the most contaminated wells at the southeast side of the island. Conclusions: Massive groundwater contamination on the island was likely caused by transport of microbiological contaminants from wastewater treatment facilities and septic tanks to the lake and the subsurface, after extreme precipitation events in May-July 2004. This likely raised the water table, saturated the subsurface, and along with very strong Lake Erie currents on 24 July, forced a surge in water levels and rapid surface water-groundwater interchange throughout the island. Landsat images showed massive influx of organic material and turbidity surrounding the island before the peak of the outbreak. These combinations of factors and information can be used t o examine vulnerabilities in other coastal systems. Both wastewater and drinking water issues are now being addressed by the Ohio Environmental Protection Agency and the Ohio Department of Health.

A Model Examining Hierarchical Wetland Networks for Watershed Stormwater Management
Authors: Matthew J. Cohen and Mark T. Brown
Affiliations: Center for Environmental Policy, Department of Environmental Engineering Sciences, PO Box 116350, Gainesville, FL 32611-6350, United States
Source: Ecological Modelling, February 24, 2007, 201(2): 179-193

Abstract: There is increasing awareness that solutions to degraded quality and excessive quantity of stormwater and resulting impacts on downstream water bodies may require a watershed approach to management rather that the incremental approach that is now common. Examination of low-relief watersheds characteristic of the southeastern coastal plain reveals common hierarchical patterns of surface water convergence that may be emulated in developed watersheds to enhance the efficacy of peak-flow attenuation and pollutant removal. A dynamic systems model was developed to compare stormwater management using a hierarchical network of treatment wetlands with the standard incremental approach wherein treatment systems are designed considering only site-level effluent criteria. The model simulates watershed hydrology, suspended sediment transport and phosphorus removal and transformation. Results indicate that watershed planning of stormwater collection and treatment systems using hierarchical networks can greatly enhance overall effectiveness (annual retention improvements of 31% for flow, 36% for sediment and 27% for phosphorus) with respect to an equal area of uniformly sized wetlands. Further, network proportions can be adjusted to specific runoff characteristics. Distinct roles were observed for each wetland size class: small headwater wetlands effectively removed sediment, medium-sized mid-reach wetlands retained phosphorus, while large wetlands primarily stored and attenuated long-period hydrologic flows.

Monitoring Subsurface Contamination Using Tree Branches
Authors: Gopalakrishnan, Gayathri; Negri, M. Cristina; Minsker, Barbara S.; Werth, Charles J.
Source: Ground Water Monitoring & Remediation, Winter 2007, 27(1): 65-74(10)

Abstract: This paper proposes a method of assessing the distribution of chlorinated solvents in soil and ground water using tree branches. Sampling branches is a potentially more cost-effective and easier method than sampling tree cores, with less risk of damage to the tree. This approach was tested at Argonne National Laboratory, where phytoremediation is being used to remove tetrachloroethene (PCE), trichloroethene (TCE), and carbon tetrachloride (CCl4) from soil and ground water. The phytoremediation system consists of shallow-rooted willows planted in an area with contaminated soil and deep-rooted poplars planted in an area with clean soil and contaminated ground water. Branch samples were collected from 126 willows and 120 poplars. Contaminant concentrations from 31 soil borings and six monitoring wells were compared to those from branches of adjacent trees. Regression equations with correlation coefficients of at least 0.89 were obtained, which were found to be chemical specific. Kriged profiles of TCE concentration based on soil and willow branch data were developed and showed good agreement. Profiles based on ground water data could not be developed due to lack of sufficient monitoring wells for a meaningful statistical analysis. An analytical model was used to simulate TCE concentrations in tree branches from soil concentrations; the diffusion coefficient for TCE in the tree was used as the fitting parameter and the best-fit value was two orders of magnitude greater than literature values. This work indicates that tree branch sampling is a useful approach to assess contaminant distribution and potentially to determine where to locate monitoring wells or perform detailed soil analysis. Further research is necessary prior to using this method as a quantitative monitoring tool for soil and ground water.

Multivariate Logistic Regression for Predicting Total Culturable Virus Presence at the Intake of a Potable-Water Treatment Plant: Novel Application of the Atypical Coliform/Total Coliform Ratio
Authors: L. E. Black¹, G. M. Brion^1,2* and S. J. Freitas²
Affiliations: Civil Engineering, College of Engineering, University of Kentucky, Lexington, Kentucky,¹ College of Public Health, University of Kentucky, Lexington, Kentucky²
Source: Applied and Environmental Microbiology, June 2007, 73(12):3965-3974

Abstract: Predicting the presence of enteric viruses in surface waters is a complex modeling problem. Multiple water quality parameters that indicate the presence of human fecal material, the load of fecal material, and the amount of time fecal material has been in the environment are needed. This paper presents the results of a multiyear study of raw-water quality at the inlet of a potable-water plant that related 17 physical, chemical, and biological indices to the presence of enteric viruses as indicated by cytopathic changes in cell cultures. It was found that several simple, multivariate logistic regression models that could reliably identify observations of the presence or absence of total culturable virus could be fitted. The best models developed combined a fecal age indicator (the atypical coliform [AC]/total coliform [TC] ratio), the detectable presence of a human-associated sterol (epicoprostanol) to indicate the fecal source, and one of several fecal load indicators (the levels of Giardia species cysts, coliform bacteria, and coprostanol). The best fit to the data was found when the AC/TC ratio, the presence of epicoprostanol, and the density of fecal coliform bacteria were input into a simple, multivariate logistic regression equation, resulting in 84.5% and 78.6% accuracies for the identification of the presence and absence of total culturable virus, respectively. The AC/TC ratio was the most influential input variable in all of the models generated, but producing the best prediction required additional input related to the fecal source and the fecal load. The potential for replacing microbial indicators of fecal load with levels of coprostanol was proposed and evaluated by multivariate logistic regression modeling for the presence and absence of virus.

Nanofiltration and Reverse Osmosis Biostability Relative to Alternative Methods of Water Treatment
Authors: Suibing Liu, Michael LePuil, J. S. Taylor and A. A. Randall
Affiliations: CDM Inc., 2301 Maitland Center Pkwy, STE 300Maitland, FL 32751, USA Center for Biomarker Analysis, Biological Imaging Unit, University of Tennessee, 10515 Research Drive, Suite 300,Knoxville, TN 37932, USA Department of Civil and Environmental Engineering, University of Central Florida, PO Box 162450Orlando, FL 32816-2450, USA Tel.:+1 (407) 823 2785Fax: +1 (407) 823 3315 taylor@mail.ucf.edu
Source: Journal of Water Supply: Research and Technology, 2007, 56(1): 25-40

Abstract: Biostability of finished waters was assessed statistically using assimilable organic carbon, biodegradable dissolved organic carbon and heterotrophic plate counts. Biofilm growth on unlined cast iron, galvanized steel, lined cast iron and polyvinylchloride pipe material was assessed visually and statistically using potential exoproteolytic activity, which is a measure of biofilm cell density. Seven different treatment processes were used to simulate full scale treatment and distribution of ground, surface and saline Source:s to pilot distribution systems made from unlined cast iron, galvanized, lined cast iron and polyvinylchloride pipes taken from actual distribution systems. Bulk water biostability parameters as measured by assimilable organic carbon, biodegradable dissolved organic carbon and heterotrophic plate counts were lower in reverse osmosis finished water and higher in conventionally treated groundwater. Average finished water assimilable organic carbon indicated reverse osmosis and nanofiltration membrane processes reduced assimilable organic carbon relative to finished groundwater produced by conventional treatment or softening, and finished surface water produced by enhanced coagulation. This relationship was not observed clearly for biodegradable dissolved organic carbon or heterotrophic plate counts. Biofilm growth on coupons cut from the pipes used to build the pilot distribution systems typically decreased as the level of treatment increased with the exception of reverse osmosis finished water, which produced very high biofilm growth. However, the assessment of biostability indicated biostability generally increased as the level of treatment increased, and the general order of biostability of process finished waters was: membrane › precipitative › conventional; and the order of biofilm growth with respect to pipe material was unlined cast iron › galvanized › lined cast iron › polyvinylchloride. Hence, improved distribution system biological water quality, as measured by lower assimilable organic carbon, biodegradable dissolved organic carbon, heterotrophic plate counts and biofilm growth, was directly dependent on nonpurgeable organic carbon and improved as finished water nonpurgeable organic carbon decreased.

New Ecotoxicological Model To Simulate Survival of Aquatic Invertebrates after Exposure to Fluctuating and Sequential Pulses of Pesticides
Authors: Roman Ashauer, Alistair B. A. Boxall, and Colin D. Brown
Affiliations: Environment Department, University of York, Heslington, York YO10 5DD, United Kingdom, and Central Science Laboratory, Sand Hutton, York YO41 1LZ, United Kingdom
Source: Environmental Science Technology, January 11, 2007, 41(4): 1480 -1486

Abstract: Aquatic nontarget organisms are exposed to fluctuating concentrations or sequential pulses of contaminants, so we need to predict effects resulting from such patterns of exposure. We present a process-based model, the Threshold Damage Model (TDM), that links exposure with effects and demonstrate how to simulate the survival of the aquatic invertebrate Gammarus pulex. Based on survival experiments of up to 28 days duration with three patterns of repeated exposure pulses and fluctuating concentrations of two pesticides with contrasting modes of action (pentachlorophenol and chlorpyrifos) we evaluate the new model and compare it to two approaches based on time-weighted averages. Two models, the Threshold Damage Model and the time-weighted averages fitted to pulses, are able to simulate the observed survival (mean errors 15% or less, r2 between 0.77 and 0.96). The models are discussed with respect to their theoretical base, data needs, and potential for extrapolation to different scenarios. The Threshold Damage Model is particularly useful because its parameters can be used to calculate recovery times, toxicokinetics are separated from toxicodynamics, and parameter values reflect the mode of action.

New Methods in Modeling Sources Specific Bacteria at Watershed Scale Using SWAT
Authors: Prem B Parajuli, Kyle R Mankin, Philip L Barnes
Citation: Watershed ManWatershed Management to Meet Water Quality Standards and TMDLS (Total Maximum Daily Load) Proceedings of the 10-14 March 2007, San Antonio, Texas 701P0207.
Source: American Society of Agricultural and Biological Engineers

Abstract: Fecal coliform bacteria contamination is one of the causes of water-quality impairments in surface waters which often result from the non-point source pollution, including grazing operations, failing septic system and wildlife. The Soil and Water Assessment Tool (SWAT) microbial sub-model 2005, was used to simulate the daily flows, total suspended solids, and fecal coliform bacteria concentrations in three grazed sub-watersheds (Auburn, Deer Creek, Rock Creek) of the Upper Wakarusa watershed in the northeast Kansas. The watershed characteristics for bacterial source, such as livestock, human, and wildlife, were modeled with four separate combinations to evaluate the source specific bacteria concentration at the outlet of the each watershed using modified deterministic probability of bacteria source tracking data.

Nitrate Retention in Riparian Ground Water at Natural and Elevated Nitrate Levels in North Central Minnesota
Authors: John H. Duff, Alan P. Jackman, Frank J. Triska, Richard W. Sheibley and Ronald J. Avanzino
Affiliations: U.S. Geological Survey, Water Resources Division, 345 Middlefield Road, MS 439, Menlo Park, CA 94025, Dep. of Chemical Engineering and Materials Science, Univ. of California, Davis, CA 95616
Source: Journal of Environmental Quality, January 25, 2007, 36: 343-353

Abstract The relationship between local ground water flows and NO3– transport to the channel was examined in three well transects from a natural, wooded riparian zone adjacent to the Shingobee River, MN. The hillslope ground water originated as recharge from intermittently grazed pasture up slope of the site. In the hillslope transect perpendicular to the stream, ground water NO3– concentrations decreased from 3 mg N L–1 beneath the ridge (80 m from the channel) to 0.01 to 1.0 mg N L–1 at wells 1 to 3 m from the channel. The Cl– concentrations and NO3/Cl ratios decreased toward the channel indicating NO3– dilution and biotic retention. In the bankside well transect parallel to the stream, two distinct ground water environments were observed: an alluvial environment upstream of a relict beaver dam influenced by stream water and a hillslope environment downstream of the relict beaver dam. Nitrate was elevated to levels representative of agricultural runoff in a third well transect located 5 m from the stream to assess the effectiveness of the riparian zone as a NO3– sink. Subsurface NO3– injections revealed transport of up to 15 mg N L–1 was nearly conservative in the alluvial riparian environment. Addition of glucose stimulated dissolved oxygen uptake and promoted NO3– retention under both background and elevated NO3– levels in summer and winter. Disappearance of added NO3– was followed by transient NO2– formation and, in the presence of C2H2, by N2O formation, demonstrating potential denitrification. Under current land use, most NO3– associated with local ground water is biotically retained or diluted before reaching the channel. However, elevating NO3– levels through agricultural cultivation would likely result in increased NO3– transport to the channel.

Numerical Modeling of Water Quality and Sediment Related Processes
Authors: Xiaobo Chao^a, , Yafei Jia^a, F. Douglas Shields, Jr.^b, Sam S.Y. Wang^a and Charles M. Cooper^b
Affiliaitons: ^aNational Center for Computational Hydroscience and Engineering, University of Mississippi, Carrier Hall 102, University, MS 38677, United States, ^bNational Sedimentation Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Oxford, MS 38655, United States
Source: Ecological Modeling, 10 March 2007, 201(3-4):385-397

Abstract: A three-dimensional water quality model (CCHE3D_WQ) was developed for simulating temporal and spatial variations of water quality with respect to phytoplankton, nutrients, and dissolved oxygen. Four major interacting systems were simulated, including phytoplankton dynamics, nitrogen cycle, phosphorus cycle, and dissolved oxygen balance. The effects of suspended and bed sediment on the water quality processes were also considered. The model was verified using analytical solutions for the transport of non-conservative substances in open channel flow, and then calibrated and validated by applying it to the study of the water quality of a natural shallow oxbow lake. The simulated time serial concentration of phytoplankton (as chlorophyll) and nutrients were generally in good agreement with field observations. Sensitivity studies were then conducted to demonstrate the impacts on water quality due to varying nutrients and suspended sediment

Nutrient Load Generated by Storm Event Runoff from a Golf Course Watershed
Authors: K. W. King^a,*, J. C. Balogh^b, K. L. Hughes^c and R. D. Harmel^d
Affiliations: a USDA-ARS, 590 Woody Hayes Drive, Columbus, OH 43210, b Spectrum Research Inc., 4915 E. Superior St., Suite 100, Duluth, MN 55804, c The Ohio State Univ., 590 Woody Hayes Dr., Columbus, OH 43210, d USDA-ARS, 808 E. Blackland Rd., Temple, TX 76502
Source: Journal Environmental Quality, 25 May 2007 36:1021-1030

Abstract: Turf, including home lawns, roadsides, golf courses, parks, etc., is often the most intensively managed land use in the urban landscape. Substantial inputs of fertilizers and water to maintain turf systems have led to a perception that turf systems are a major contributor to nonpoint source water pollution. The primary objective of this study was to quantify nutrient (NO3–N, NH4–N, and PO4–P) transport in storm-generated surface runoff from a golf course. Storm event samples were collected for 5 yr (1 Apr. 1998–31 Mar. 2003) from the Morris Williams Municipal Golf Course in Austin, TX. Inflow and outflow samples were collected from a stream that transected the golf course. One hundred fifteen runoff-producing precipitation events were measured. Median NO3–N and PO4–P concentrations at the outflow location were significantly (p ‹ 0.05) greater than like concentrations measured at the inflow location; however, median outflow NH4–N concentration was significantly less than the median inflow concentration. Storm water runoff transported 1.2 kg NO3–N ha–1 yr–1, 0.23 kg NH4–N ha–1 yr–1, and 0.51 kg PO4–P ha–1 yr–1 from the course. These amounts represent approximately 3.3% of applied N and 6.2% of applied P over the contributing area for the same period. NO3–N transport in storm water runoff from this course does not pose a substantial environmental risk; however, the median PO4–P concentration exiting the course exceeded the USEPA recommendation of 0.1 mg L–1 for streams not discharging into lakes. The PO4–P load measured in this study was comparable to soluble P rates measured from agricultural lands. The findings of this study emphasize the need to balance golf course fertility management with environmental risks, especially with respect to phosphorus.

Occurrence of Virulence and Antimicrobial Resistance Genes in Escherichia coli Isolates from Different Aquatic Ecosystems within the St. Clair River and Detroit River Areas
Authors: Katia Hamelin, Guillaume Bruant, Abdel El-Shaarawi, Stephen Hill, Thomas A. Edge, John Fairbrother, Josée Harel, Christine Maynard, Luke Masson, and Roland Brousseau
Affilliations Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Ave., Montreal, Quebec, Canada H4P 2R2,1 Department of Microbiology and Immunology, Université de Montréal, 2900 boul. Edouard Montpetit, Montreal, Quebec, Canada H3T 1J4,2 Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 rue Sicotte, Saint-Hyacinthe, Quebec, Canada J2S 7C6,3 National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, Canada L7R 4A64
Source: Applied and Environmental Microbiology, January 2007, 73(2): 477-484

Abstract: Although the number of Escherichia coli bacteria in surface waters can differ greatly between locations, relatively little is known about the distribution of E. coli pathotypes in surface waters used as Source:s for drinking or recreation. DNA microarray technology is a suitable tool for this type of study due to its ability to detect high numbers of virulence and antimicrobial resistance genes simultaneously. Pathotype, phylogenetic group, and antimicrobial resistance gene profiles were determined for 308 E. coli isolates from surface water samples collected from diverse aquatic ecosystems at six different sites in the St. Clair River and Detroit River areas. A higher frequency (48%) of E. coli isolates possessing virulence and antimicrobial resistance genes was observed in an urban site located downstream of wastewater effluent outfalls than in the other examined sites (average of 24%). Most E. coli pathotypes were extraintestinal pathogenic E. coli (ExPEC) pathotypes and belonged to phylogenetic groups B2 and D. The ExPEC pathotypes were found to occur across all aquatic ecosystems investigated, including riverine, estuarine, and offshore lake locations. The results of this environmental study using DNA microarrays highlight the widespread distribution of E. coli pathotypes in aquatic ecosystems and the potential public health threat of E. coli pathotypes originating from municipal wastewater Source:s.

Origin of a Mixed Brominated Ethene Groundwater Plume: Contaminant Degradation Pathways and Reactions
Authors: Bradley M. Patterson, Elizabeth Cohen, Henning Prommer, David G Thomas, Stuart Rhodes, and Allan J. McKinley
Affiliations: CSIRO Land and Water, Private Bag No. 5, Wembley, WA 6913, Faculty of Life and Physical Sciences, University of Western Australia, Crawley, WA 6907, Golder Associates, P.O. Box 1914, West Perth, WA 6872, and Rio Tinto Technical Services, Ground Floor, 120 Christie Street, St. Leonards, NSW 2065, Australia
Source: Environmental Science Technology, January 12, 2007, 41(4): 1352 -1358

Abstract: On the basis of a combination of laboratory microcosm experiments, column sorption experiments, and the current spatial distribution of groundwater concentrations, the origin of a mixed brominated ethene groundwater plume and its degradation pathway were hypothesized. The contaminant groundwater plume was detected downgradient of a former mineral processing facility, and consisted of tribromoethene (TriBE), cis-1,2-dibromoethene (c-DBE), trans-1,2-dibromoethene (t-DBE), and vinyl bromide (VB). The combined laboratory and field data provided strong evidence that the origin of the mixed brominated ethene plume was a result of dissolution of the dense non-aqueous-phase liquid 1,1,2,2-tetrabromoethane (TBA) at the presumed Source: zone, which degraded rapidly (half-life of 0.2 days) to form TriBE in near stoichiometric amounts. TriBE then degraded (half-life of 96 days) to form c-DBE, t-DBE, and VB via a reductive debromination degradation pathway. Slow degradation of c-DBE (half-life ›220 days), t-DBE (half-life 220 days), and VB (half-life ›220 days) coupled with their low retardation coefficients (1.2, 1.2, and 1.0 respectively) resulted in the formation of an extensive mixed brominated ethene contaminant plume. Without this clearer understanding of the mechanism for TBA degradation, the origin of the mixed brominated ethene groundwater contamination could have been misinterpreted, and inappropriate and ineffective Source: zone and groundwater remediation techniques could be applied.

Passive Flux Meter Measurement of Water and Nutrient Flux in Saturated Porous Media: Bench-Scale Laboratory Tests
Authors: Jaehyun Cho^a, Michael D. Annablea,*, James W. Jawitz^b and Kirk Hatfield^c
Affiliations: a Dep. of Environmental Engineering Sciences, Univ. of Florida, Gainesville, FL 32611, b Soil and Water Science Dep., Univ. of Florida, Gainesville, FL 32611, c Dep. of Civil and Coastal Engineering, Univ. of Florida, Gainesville, FL 32611
Source: Journal Environmental Quality, 17 July 2007, 36:1266-1272

Abstract: The passive nutrient flux meter (PNFM) is introduced for simultaneous measurement of both water and nutrient flux through saturated porous media. The PNFM comprises a porous sorbent pre-equilibrated with a suite of alcohol tracers, which have different partitioning coefficients. Water flux was estimated based on the loss of loaded resident tracers during deployment, while nutrient flux was quantified based on the nutrient solute mass captured on the sorbent. An anionic resin, Lewatit 6328 A, was used as a permeable sorbent and phosphate (PO43–) was the nutrient studied. The phosphate sorption capacity of the resin was measured in batch equilibration tests as 56 mg PO43– g–1, which was determined to be adequate capacity to retain PO43– loads intercepted over typical PNFM deployment periods in most natural systems. The PNFM design was validated with bench-scale laboratory tests for a range of 9.8 to 28.3 cm d–1 Darcy velocities and 6 to 43 h deployment durations. Nutrient and water fluxes measured by the PNFM averaged within 6 and 12% of the applied values, respectively, indicating that the PNFM shows promise as a tool for simultaneous measurement of water and nutrient fluxes.

Pathways Of River Nutrients Towards The Euphotic Zone In A Deep-Reservoir Of Small Size: Uncertainty Analysis
Authors: Francisco J. Rueda^a,, William E. Fleenor^b and Inmaculada de Vicente^c
Affiliations: ^aDepartamento de Ingeniería Civil & Instituto del Agua, Universidad de Granada, C/Ramón y Cajal, 4, 18071 Granada, Spain, ^bDepartment of Civil & Environmental Engineering, University of California, Davis, United States, ^cInstituto del Agua, Universidad de Granada & Institute of Biology, University of Southern Denmark, Odense, Denmark
Source: Ecological Modeling, 10 April 2007, 202(3-4):345-361

Abstract: The ecological consequences of river inflows, usually carrying large amounts of nutrients, will be different depending on whether it penetrates to the hypolimnion, inserts in the metalimnion or remains on the surface. For plunging rivers, the intrusion depth is controlled by the river-reservoir density difference prior to the plunge point together with mixing processes between ambient and inflowing water, which occur both in the region of the plunge and after the flow has assumed the form of a density current. In contrast with the processes of entrainment into density currents, which have been extensively studied, entrainment and mixing within the plunge zone has received less attention in the physical limnology literature. The existing literature fails to identify adequate parameterizations of this phenomenon, while exhibiting a large variability in the initial mixing rate, measured both in the laboratory and in the field. This work examines the consequences (in terms of uncertainty) that our lack of knowledge of parameters describing river-reservoir mixing in 1-D transport models has on the estimates of river nutrient loads into the euphotic zone of a reservoir, where nutrients are readily available for phytoplankton growth.

Phosphorus Dynamics At Multiple Time Scales In The Pelagic Zone Of A Large Shallow Lake In Florida, USA
Authors: Karl E. Havens, Kang-Ren Jin, Nenad Iricanin and R. Thomas James
Affiliations: Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL 33458, USA, South Florida Water Management District, West Palm Beach, FL 33406, USA
Source: Hydrobiologia, March 16, 2007, 581(1): 25-42

Abstract: Phosphorus (P) dynamics in large shallow lakes are greatly influenced by physical processes such as wind-driven sediment resuspension, at times scales from hours to years. Results from long-term (30 year) research on Lake Okeechobee, Florida (area 1,730 km2, mean depth 2.7 m) illustrate key features of these P dynamics. Variations in wind velocity result in changes in water column transparency, suspended solids, and total P (TP). In summer there are diurnal changes in TP associated with afternoon winds, and in winter, when strong winds occur for multiple days, monthly average TP remains high compared to summer. The magnitude of daily and seasonal TP changes can exceed 100 µg l–1. Hurricanes and tropical storms also cause extreme changes in TP that are superimposed on seasonal dynamics. When a hurricane passed 80 km south of the lake in October 1999, mean pelagic TP increased from 88 to 222 µg l–1. During large resuspension events, light attenuation is substantially increased, and this influences the biomass and spatial extent of submerged plants, as well as water column TP. In Lake Okeechobee, TP concentrations typically are 20 µg l–1 when submerged plants are dense, and soluble reactive P concentrations are reduced below detection, perhaps by the periphyton and plant uptake and by precipitation with calcium at high pH. In contrast, TP exceeds 50 µg l–1 when submerged plants and periphyton are absent due to prolonged deep water, and phytoplankton biomass and algal bloom frequency both are increased. In Lake Okeechobee and other large shallow lakes, complex models that explicitly consider wind-wave energy, hydrodynamics, and sediment resuspension, transport, and key biological processes are needed to accurately predict how lake water TP will respond to different management options.

Phosphorus Transport Pathways to Streams in Tile-Drained Agricultural Watersheds
Authors: L. E. Gentry, M. B. David, T. V. Royer, C. A. Mitchell and K. M. Starks
Affiliations: Dep. of Natural ReSource:s and Environmental Sciences, Univ. of Illinois at Urbana-Champaign, 1102 S. Goodwin Ave., Urbana, IL 61801b School of Public and Environmental Affairs, Indiana Univ., 1315 E. Tenth St., Bloomington, IL 47405 current address, Dep. of Crop and Soil Sciences, Michigan State Univ., 572 Plant and Soil Sciences Bldg., East Lansing, MI 48825
Source: Journal of Environmental Quality, January 25, 2007, 36: 408-415

Abstract: Received for publication March 9, 2006. Agriculture is a major nonpoint Source: of phosphorus (P) in the Midwest, but how surface runoff and tile drainage interact to affect temporal concentrations and fluxes of both dissolved and particulate P remains unclear. Our objective was to determine the dominant form of P in streams (dissolved or particulate) and identify the mode of transport of this P from fields to streams in tile-drained agricultural watersheds. We measured dissolved reactive P (DRP) and total P (TP) concentrations and loads in stream and tile water in the upper reaches of three watersheds in east-central Illinois (Embarras River, Lake Fork of the Kaskaskia River, and Big Ditch of the Sangamon River). For all 16 water year by watershed combinations examined, annual flow-weighted mean TP concentrations were ›0.1 mg L–1, and seven water year by watershed combinations exceeded 0.2 mg L–1. Concentrations of DRP and particulate P (PP) increased with stream discharge; however, particulate P was the dominant form during overland runoff events, which greatly affected annual TP loads. Concentrations of DRP and PP in tiles increased with discharge, indicating tiles were a Source: of P to streams. Across watersheds, the greatest DRP concentrations (as high as 1.25 mg L–1) were associated with a precipitation event that followed widespread application of P fertilizer on frozen soils. Although eliminating this practice would reduce the potential for overland runoff of P, soil erosion and tile drainage would continue to be important transport pathways of P to streams in east-central Illinois.

Polychlorinated Biphenyl Release from Resuspended Hudson River Sediment
Authors: Abby R. Schneider, Elka T. Porter, and Joel E. Baker
Affiliations: Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, 1 Williams Street, Solomons, Maryland 20688
Source: Environmental Science Technology, January 17, 2007, 41(4): 1097 -1103

Abstract: Three shear turbulence resuspension mesocosms (STORM tanks) were used to examine the release of polychlorinated biphenyls (PCBs) from resuspended Hudson River sediment. Twenty-two percent of the resuspended PCBs desorbed after 2 h, and 35% ± 8% of PCBs were in the dissolved phase after apparent steady state was reached in 2 days. After the first resuspension event, the solids were allowed to settle and the quiescent time was varied to determine whether the labile pool of PCBs is recharged during sediment consolidation. The steady-state log Koc values for the third subsequent resuspension were higher than for the first event due to lower dissolved PCB concentrations; the particulate PCB concentrations were constant between events. With 1 day of consolidation between resuspension events, the dissolved concentration of all congeners decreased an average of 8% ± 5% between subsequent resuspension events. With 4 days between events, only the dissolved pentachlorinated PCBs decreased significantly (p = 0.002), suggesting that the easily desorbable PCBs recharge when there is sufficient time between resuspension events.

Predicting Runoff of Suspended Solids and Particulate Phosphorus for Selected Louisiana Soils Using Simple Soil Tests
Authors: Theophilus K. Udeigwe^a, Jim J. Wanga,* and Hailin Zhang^b
Affiliations: a School of Plant, Environmental, and Soil Sciences, Sturgis Hall, Louisiana State Univ. Agricultural Center, Baton Rouge, LA 70803,m b Dep. of Plant and Soil Sciences, Oklahoma State Univ., Stillwater, OK 74078. Contribution of Louisiana Agric. Exp. Stn. Journal No. 06-14-0300 and is published with the approval of the Director
Source: Journal of Environmental Quality, 17 July 2007, 36:1310-1317

Abstract: This study was conducted to evaluate the relationships among total suspended solids (TSS) and particulate phosphorus (PP) in runoff and selected soil properties. Nine Louisiana soils were subjected to simulated rainfall events, and runoff collected and analyzed for various parameters. A highly significant relationship existed between runoff TSS and runoff turbidity. Both runoff TSS and turbidity were also significantly related to runoff PP, which on average accounted for more than 98% of total P (TP) in the runoff. Runoff TSS was closely and positively related to soil clay content in an exponential fashion (y = 0.10e0.01x, R2 = 0.91, P ‹ 0.001) while it was inversely related to soil electrical conductivity (EC) (y = 0.02 x–3.95, R2 = 0.70, P ‹ 0.01). A newly-devised laboratory test, termed “soil suspension turbidity” (SST) which measures turbidity in a 1:200 soil/water suspension, exhibited highly significant linear relationships with runoff TSS (y = 0.06x – 4.38, R2 = 0.82, P ‹ 0.001) and PP (y = 0.04x + 2.68, R2 = 0.85, P ‹ 0.001). In addition, SST alone yielded similar R2 value to that of combining soil clay content and EC in a multiple regression, suggesting that SST was able to account for the integrated effect of clay content and electrolytic background on runoff TSS. The SST test could be used for assessment and management of sediment and particulate nutrient losses in surface runoff.

Predictors of Use and Consumption 0f Public Drinking Water Among Pregnant Women
Authors: Ulla M Forssén, Amy H Herring, David A Savitz, Mark J Nieuwenhuijsen, Patricia A Murphy, Philip C Singer and J Michael Wright
Affiliations: Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, North Carolina, USA, Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, Department of Biostatistics, School of Public Health, University of North Carolina, Chapel Hill, North Carolina, USA, Department of Community and Preventive Medicine, Mount Sinai School of Medicine, New York, New York, USA, Department of Epidemiology and Public Health, Imperial College, London, UK, US EPA, National Center for Environmental Assessment, Cincinnati, Ohio, USA, Department of Environmental Science and Engineering, School of Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
Source: Journal of Exposure Science and Environmental Epidemiology, April 11, 2007

Abstract: Disinfection by-products (DBPs) in drinking water may be associated with adverse pregnancy outcomes. However, the results from previous epidemiological studies are not consistent, perhaps in part due to individual variation in water use and consumption. This study was performed to evaluate and describe demographic and behavioral characteristics as predictors of ingested water, showering, bathing, and swimming among pregnant women. Water use and consumption data were collected through telephone interviews with 2297 pregnant women from three geographical sites in the southern United States. The data were analyzed according to demographic, health, and behavioral variables expected to be predictors of water use and thus potential confounding factors relating water use to pregnancy outcome. The candidate predictors were evaluated using backward elimination in regression models. Demographic variables tended to be more strongly predictive of the use and consumption of water than health and behavior-related factors. Non-Hispanic white women drank 0.4 (95% confidence interval (CI) 0.2; 0.7) liters more cold tap water per day than Hispanic women and 0.3 (95% CI 0.1; 0.4) liters more than non-Hispanic black women. Non-Hispanic white women also reported drinking a higher proportion of filtered tap water, whereas Hispanic women replaced more of their tap water with bottled water. Lower socioeconomic groups reported spending a longer time showering and bathing, but were less likely to use swimming pools. The results of this study should help researchers to anticipate and better control for confounding and misclassification in studies of exposure to DBPs and pregnancy outcomes.

Prevalence of Bacterial Pathogens in Biofilms of Drinking Water Distribution Systems
Authors: S. M. September, F. A. Els, S. N. Venter and V. S. Brózel
Affiliations: Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria, 0002, South Africa NPB 252B, Department of Biology and Microbiology, Box 2140DSouth Dakota State University, Brookings, SD 57007, USA
Source: Journal of Water and Health, 2007, 5(2): 219-227

Abstract: Water for human consumption is required to be free from any bacteria that might pose a health risk. The presence of biofilms in the drinking water distribution system may play a role in the presence of potential pathogens in the drinking water supply. Ninety-five biofilm samples from various parts of South Africa were tested for the presence of Escherichia coli, Aeromonas, Pseudomonas, Salmonella, Shigella and Vibrio spp. Members of these genera were quantified by the three-tube most probable number (MPN) approach using enrichment broths and plating on selective agars. The heterotrophic culturable counts were determined for both the planktonic and biofilm phases of the samples. Biofilm density varied between 10 and 1.9 × 109 colony forming units cm-2. The 16S rRNA identity of the putative pathogenic isolates revealed that high numbers of Aeromonas, Pseudomonas, Klebsiella and Enterobacter were present, but no putative Salmonella and Shigella could be confirmed. None of the Pseudomonas isolates belonged to the pathogenic Pseudomonas aeruginosa or Pseudomonas mendocina while the Aeromonas isolates showed relatedness to known pathogenic members of this group.

Relating Planktonic Microbial Food Web Structure In Lentic Freshwater Ecosystems To Water Quality And Land Use
Authors: Carolyn W. Burns and Lisa M. Galbraith
Affiliation: Department of Zoology, University of Otago, Box 56, Dunedin, New Zealand
Source: Journal of Plankton Research January 15, 2007 29(2): 127-139

Abstract: Relationships among picoplankton, protozoa, phytoplankton, plant nutrients, lake type, drainage basin morphology and land cover were studied in 45 water bodies in South Island, New Zealand that ranged from large, deep, ultra-oligotrophic lakes to shallow, macrophyte-dominated ponds and swamps. The biomasses of most heterotrophic components of the pelagic microbial food webs were positively related to phytoplankton and features of the drainage basin that enhanced nutrient input, and imply strong resource-driven structuring of pelagic microbial food webs. Prokaryotic picophytoplankton biomass was negatively related to indices of eutrophication, and the picoautotroph contribution to total microbial food web biomass declined with increasing total phosphorus concentration from 16.5% in deep lakes to ‹0.02% in swamps and ponds. Biomass ratios of (picoplankton plus protozoa):phytoplankton ranged from 40:60 in swamps and ponds to ›70:30 in deep lakes, and indicate the potential importance of microbial food webs in carbon transfer to higher trophic levels in deep, less productive lakes. Strong relationships exist between land use in the catchment and pelagic microbial food web structure and biomass across a wide range in size and trophic state of water bodies in heterogeneous landscapes.

Relationships between Soil and Runoff Phosphorus in Small Alberta Watersheds
Author: Joanne L. Littlea,*, Sheilah C. Nolana, Janna P. Cassonb and Barry M. Olsonb
Affiliations: a Alberta Agriculture and Food, Conservation and Development Branch, 206, 7000, 113 St. Edmonton, AB, T6H 5T6, b Alberta Agriculture and Food, Irrigation Branch, 100, 5401, 1st Ave S., Lethbridge, AB T1J 4V6
Source: Journal of Environmental Quality, 17 July 2007, 36:1289-1300

Abstract: Field-scale relationships between soil test phosphorus (STP) and flow-weighted mean concentrations (FWMCs) of dissolved reactive phosphorus (DRP) and total phosphorus (TP) in runoff are essential for modeling phosphorus losses, but are lacking. The objectives of this study were (i) to determine the relationships between soil phosphorus (STP and degree of phosphorus saturation (DPS)) and runoff phosphorus (TP and DRP) from field-sized catchments under spring snowmelt and summer rainfall conditions, and (ii) to determine whether a variety of depths and spatial representations of STP improved the prediction of phosphorus losses. Runoff was monitored from eight field-scale microwatersheds (2 to 248 ha) for 3 yr. Soil test phosphorus was determined for three layers (0 to 2.5 cm, 0 to 5 cm, and 0 to 15 cm) in spring and fall and the DPS was determined for the surface layer. Average STP (0 to 15 cm) ranged from 3 to 512 mg kg–1, and DPS (0 to 2.5 cm) ranged from 5 to 91%. Seasonal FWMCs ranged from 0.01 to 7.4 mg L–1 DRP and from 0.1 to 8.0 mg L–1 TP. Strong linear relationships (r2 = 0.87 to 0.89) were found between the site mean STP and the FWMCs of DRP and TP. The relationships had similar extraction coefficients, intercepts, and predictive power among all three soil layers. Extraction coefficients (0.013 to 0.014) were similar to those reported for other Alberta studies, but were greater than those reported for rainfall simulation studies. The curvilinear DPS relationship showed similar predictive ability to STP. The field-scale STP relationships derived from natural conditions in this study should provide the basis for modeling phosphorus in Alberta.

Removal of Cadmium from Wastewaters by Aragonite Shells and the Influence of Other Divalent Cations
Authors: Stephan Jürgen Köhler, Pablo Cubillas, Juan Diego Rodríguez-Blanco, Christoph Bauer, and Manuel Prieto
Affiliations: Institute for Applied Geosciences, Rechbauerstrasse 12, A-8010 Graz, Austria, Departamento de Geología, Universidad de Oviedo, Jesús Arias de Velasco s/n 33005, Oviedo, Asturias, Spain, and Institute of Earth Sciences, Karl-Franzens Universität, Universitätsplatz 2, A-8010 Graz, Austria
Source: Environmental Science and Technology, November 21, 2006, 41 (1): 112-118, 2007

Abstract: The effect of dissolved Zn, Co, Pb, Mg, and Ca on the uptake of cadmium by biogenic aragonite was investigated. Experiments were performed in batch-reactors using metal-cadmium-bearing solutions and shell fragments with diameters in different ranges, the solid/liquid ratio being 10 grams per liter. Different initial concentrations of cadmium and metals (1.0-0.005 mM) were used. Uptake takes place via heterogeneous nucleation of metal-bearing crystallites onto the shell surfaces. Cadmium removal occurs by surface precipitation of otavite. Under the conditions used here, Co and Ca as well as Pb 0.3 mM and Zn 0.3 mM do not have a significant effect on the removal of cadmium. At higher concentrations, Pb and Zn outcompete Cd for the dissolving carbonate ions and thus decrease significantly the Cd removal rates. In contrast, Mg has a slight enhancing effect. Pb and Zn are removed faster than Cd, precipitating as PbCO3, Pb3(CO3)2(OH)2, and Zn5(CO3)2(OH)6. Within 24-72 h, the concentrations of lead, cadmium, and zinc decrease until ~0.5 M, and the presence of aragonite buffers the solution to a pH above 8 avoiding redissolution. The study demonstrates the high effectiveness of biogenic aragonite in removing Cd and other metals from polluted waters.

Removal of Native Coliphages and Coliform Bacteria from Municipal Wastewater by Various Wastewater Treatment Processes: Implications to Water Reuse
Authors: K. Zhang and K. Farahbakhsh
Affiliation School of Engineering, University of Guelph, Guelph, Ont., Canada N1G 2W1
Source: Water ReSource:, June 2007, 41(12): 2816-24

Abstract: The efficacy of a conventional activated sludge wastewater treatment process and the membrane bioreactor technology in removing microbial pathogens was investigated. Total and fecal coliforms and somatic and F-specific coliphages were used as indicators of pathogenic bacteria and viruses. Up to 5.7 logs removal of coliforms and 5.5 logs of coliphages were observed in the conventional treatment process with advanced tertiary treatment. Addition of chemical coagulants seemed to improve the efficacy of primary and secondary treatment for microorganism removal. Complete removal of fecal coliforms and up to 5.8 logs removal of coliphages was observed in the MBR system. It was shown that the MBR system was capable of high removal of coliphages despite the variation in feed coliphage concentrations. The results of this study indicated that the MBR system can achieve better microbial removal in far fewer steps than the conventional activated sludge process with advanced tertiary treatment. The final effluent from either treatment processes can be potentially reused.

Restoring Streams in an Urbanizing World
Authors: Bernhardt, Emily S., Palmer, Margaret A.
Source: Freshwater Biology, April 2007, 52(4): 738-751(14)

Abstract:
1. The world's population is increasingly urban, and streams and rivers, as the low lying points of the landscape, are especially sensitive to and profoundly impacted by the changes associated with urbanization and suburbanization of catchments.
2. River restoration is an increasingly popular management strategy for improving the physical and ecological conditions of degraded urban streams. In urban catchments, management activities as diverse as stormwater management, bank stabilisation, channel reconfiguration and riparian replanting may be described as river restoration projects.
3. Restoration in urban streams is both more expensive and more difficult than restoration in less densely populated catchments. High property values and finely subdivided land and dense human infrastructure (e.g. roads, sewer lines) limit the spatial extent of urban river restoration options, while stormwaters and the associated sediment and pollutant loads may limit the potential for restoration projects to reverse degradation.
4. To be effective, urban stream restoration efforts must be integrated within broader catchment management strategies. A key scientific and management challenge is to establish criteria for determining when the design options for urban river restoration are so constrained that a return towards reference or pre-urbanization conditions is not realistic or feasible and when river restoration presents a viable and effective strategy for improving the ecological condition of these degraded ecosystems.

A River is Reborn–Use Attainability Analysis for the Lower Des Plaines River, Illinois
Authors: Novotny, Vladimir; O'Reilly, Neal; Ehlinger, Timothy; Frevert, Toby; Twait, Scott
Source: Water Environment Research, January 2007, 79 (1): 68-80(13)

Abstract: The goal of the Use Attainability Analysis (UAA) of the Lower Des Plaines River was to upgrade the designated “Secondary Contact Recreation and Indigenous Aquatic Life Use” to a higher use that would be commensurate with the goals of the Clean Water Act (CWA). In Illinois, the water body use in compliance with the goals of the CWA is named “General Use”. The river has been extensively modified and receives most point-source and urban runoff discharges from the Chicago metropolitan area (9.5 million inhabitants). The study included an extensive assessment of the physical, chemical, biological, and bacteriological integrity status of the water body and sediments. The UAA found that the water quality situation of the river has improved significantly since the 1970s, when the Illinois Pollution Control Board defined and assigned the Secondary Contact Recreation and Indigenous Aquatic Life Use designation to the Lower Des Plaines River. The study defined and suggested a “Modified Impounded Use” for one highly modified reach, with adjusted standards for dissolved oxygen and recreation. The study also recommended adoption of the General Use standards, some of them in a modified form, for other water quality parameters. Standards for limited recreation were also developed. The UAA also outlines a suggested action plan that will bring UAA segments of the Lower Des Plaines River in compliance with UAA goals.

The Role of Headwater Streams in Downstream Water Quality
Authors: Richard B. Alexander, Elizabeth W. Boyer, Richard A. Smith, Gregory E. Schwarz, and Richard B. Moore2
Source: Journal of the American Water Resources Association, February 2007, 43(1)

Abstract: Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act ( CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to investigate headwater influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters to landscape processes and downstream waters through their influence on the supply, transport, and fate of water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass-balance watershed model SPARROW to consider transport and transformations of water and nutrients throughout stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a water-quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen transport from headwaters to downstream navigable waters, where headwaters are defined within the model as first-order, perennial streams that include flow and nitrogen contributions from smaller, intermittent and ephemeral streams. We find that first-order headwaters contribute approximately 70% of the mean-annual water volume and 65% of the nitrogen flux in second-order streams. Their contributions to mean water volume and nitrogen flux decline only marginally to about 55% and 40% in fourth- and higher-order rivers that include navigable waters and their tributaries. These results underscore the profound influence that headwater areas have on shaping downstream water quantity and water quality. The results have relevance to water-resource management and regulatory decisions and potentially broaden understanding of the spatial extent of Federal CWA jurisdiction in U.S. waters.

The Role of Plants in the Removal of Nutrients at a Constructed Wetland Treating Agricultural (Dairy) Wastewater, Ontario, Canada
Authors: N. Gottschall^a,, C. Boutin^b,, A. Crolla^c,, C. Kinsley^c, and P. Champagne^d
Affiliations: aBiology Department, Carleton University, 1125 Colonel By Drive, Ottawa, Ont. K1S 5B6, Canada, bEnvironment Canada, National Wildlife Research Centre, Carleton University, 1125 Colonel By Drive, Ottawa, Ont. K1A 0H3, Canada, cCollège d’Alfred, University of Guelph, 31 rue St. Paul, Alfred, Ont. K0B 1A0, Canada, dCivil Engineering, Queen's University, 58 University Avenue, Kingston, Ont. K7L 3N6, Canada
Source: Ecological Engineering 1 February 2007, 29(2):154-163

Abstract: The South Nation River Watershed, in eastern Ontario, Canada, is an agricultural watershed impacted by excess nutrient loading primarily from agricultural activities. A constructed wetland for the treatment of agricultural wastewater from a 150-cow dairy operation in this watershed was monitored in its eighth operating season to evaluate the proportion of total nitrogen (TN) (approximated by total Kjeldahl nitrogen (TKN) due to low NO3–) and total phosphorus (TP) removal that could be attributed to storage in Typha latifolia L. and Typha angustifolia L., which dominate this system. Nutrient loading rates were high, with 16.2 kg ha–1 d–1 N and 3.4 kg ha–1 d–1 P entering the wetland and loading the first wetland cell. Plant uptake accounted for 0.7% of TKN removal when the vegetated free water surface cells were considered together. However, separately, in the second wetland cell with lower N and P loading rates, plants accounted for 9% of TKN, 21% of NH4+ and 5% of TP removal. Plant uptake was significant to overall removal given wetland age and nutrient loading. Nutrient storage during the growing season at this constructed wetland helped reduce the nutrient load entering the watershed, already stressed by intensive local agriculture.

The Role of Wastewater Treatment in Protecting Water Supplies Against Emerging Pathogens
Author: Crockett, Christopher S
Source: Water Environment Research, March 2007, 79(3): 221-232(12)

Abstract: Traditionally, regulators, dischargers, and even water suppliers believed that wastewater discharge meeting the levels of 200 cfu/100 mL of fecal coliforms in wastewater effluent was sufficient to protect against downstream microbial effects. However, these beliefs are now being challenged by emerging pathogens that are resistant to standard water and wastewater treatment processes, exhibit extended survival periods in the environment, can adversely affect sensitive subpopulations, and require extremely low doses for human infection. Based on this new information, it is estimated that discharges of emerging pathogens from conventional wastewater treatment plants as far as 160 km upstream and cumulative amounts of wastewater discharge ranging from 2 to 20 ML/d have the potential to reach a water supply intake in a viable state at significant concentrations that could exceed regulatory limits for drinking water supplies, increase endemic risk from drinking water, and/or require additional drinking water treatment. Wastewater dischargers may be able mitigate this potential effect and achieve upwards of 6 log combined removal and inactivation of emerging pathogens to mitigate drinking water effects by using alternative treatment processes, such as filtration or UV light disinfection, or optimizing these processes based on site-specific conditions.

Saturated Zone Denitrification: Potential for Natural Attenuation of Nitrate Contamination in Shallow Groundwater Under Dairy Operations
Authors: M. J. Singleton, B. K. Esser, J. E. Moran, G. B. Hudson, W. W. McNab, and T. Harter
Affiliations: Chemical Sciences Division, Lawrence Livermore National Laboratory, Environmental Restoration Division, Lawrence Livermore National Laboratory, and Department of Land, Air, and Water Resources, University of California at Davis
Source: Environmental Science Technology, January 3, 2007, 41(3): 759 -765

Abstract: We present results from field studies at two central California dairies that demonstrate the prevalence of saturated-zone denitrification in shallow groundwater with 3H/3He apparent ages of ‹35 years. Concentrated animal feeding operations are suspected to be major contributors of nitrate to groundwater, but saturated zone denitrification could mitigate their impact to groundwater quality. Denitrification is identified and quantified using N and O stable isotope compositions of nitrate coupled with measurements of excess N2 and residual NO3- concentrations. Nitrate in dairy groundwater from this study has 15N values (4.3-61”), and 18O values (-4.5-24.5”) that plot with 18O/ 15N slopes of 0.47-0.66, consistent with denitrification. Noble gas mass spectrometry is used to quantify recharge temperature and excess air content. Dissolved N2 is found at concentrations well above those expected for equilibrium with air or incorporation of excess air, consistent with reduction of nitrate to N2. Fractionation factors for nitrogen and oxygen isotopes in nitrate appear to be highly variable at a dairy site where denitrification is found in a laterally extensive anoxic zone 5 m below the water table, and at a second dairy site where denitrification occurs near the water table and is strongly influenced by localized lagoon seepage.

Selection of a Water-Extractable Phosphorus Test for Manures and Biosolids as an Indicator of Runoff Loss Potential
Authors: Peter Kleinmana,*, Dan Sullivanb, Ann Wolfc, Robin Brandtd, Zhengxia Doue, Herschel Elliottd, John Kovarf, April Leytemg, Rory Maguireh, Philip Moorei, Lou Saporitoa, Andrew Sharpleyj, Amy Shoberk, Tom Simsl, John Tothe, Gurpal Toorm, Hailin Zhangn and Tiequan Zhango
Affiliations: a USDA-ARS, Pasture Systems and Watershed Management Research Unit, University Park, PA 16802, b Dep. Crop and Soil Sciences, Oregon State Univ., Corvallis, OR 97331, c Agricultural Analytical Services Lab., Pennsylvania State Univ., University Park, PA 16802, d Agricultural and Biological Engineering, Pennsylvania State Univ., University Park, PA 16802, e School of Veterinary Medicine, Univ. of Pennsylvania, Kennett Square, PA 19348, f USDA-ARS, National Soil Tilth Lab., Ames, IA 50011, g USDA-ARS, Northwest Irrigation and Soils Research Lab., Kimberly, ID 83341, h Dep. of Crop and Soil Environmental Sciences, Virginia Polytechnic Univ., Blacksburg, VA 24061, i USDA-ARS, Poultry Production and Product Safety Research Unit, Fayetteville, AR 72701, j Dep. Crop, Soil and Environmental Sciences, Univ. of Arkansas, Fayetteville, AR 72701, k Dep. Soil and Water Science, Univ. of Florida, Gulf Coast Research and Education Center, Wimauma, FL 33598, l Dep. Plant and Soil Sciences, Univ. of Delaware, Newark, DE 19716, m Dep. Biological and Agricultural Engineering, Univ. of Arkansas, Fayetteville, AR 72701, n Dep. Plant and Soil Sciences, Oklahoma State Univ., Stillwater, OK 74078, o Environmental Health, Greenhouse and Processing Crops Research Center, Agriculture and Agri-Food Canada, Harrow, ON, Canada N0R 1G0. Mention of trade names does not imply recommendation or endorsement by USDA-ARS
Source: Journal of Environmental Quality, 17 July 2007, 36:1357-1367

Abstract: The correlation of runoff phosphorus (P) with water-extractable phosphorus (WEP) in land-applied manures and biosolids has spurred wide use of WEP as a water quality indicator. Land managers, planners, and researchers need a common WEP protocol to consistently use WEP in nutrient management. Our objectives were to (i) identify a common WEP protocol with sufficient accuracy and precision to be adopted by commercial testing laboratories and (ii) confirm that the common protocol is a reliable index of runoff P. Ten laboratories across North America evaluated alternative protocols with an array of manure and biosolids samples. A single laboratory analyzed all samples and conducted a separate runoff study with the manures and biosolids. Extraction ratio (solution:solids) was the most important factor affecting WEP, with WEP increasing from 10:1 to 100:1 and increasing from 100:1 to 200:1. When WEP was measured by a single laboratory, correlations with runoff P from packed soil boxes amended with manure and biosolids ranged from 0.79 to 0.92 across all protocol combinations (extraction ratio, filtration method, and P determination method). Correlations with P in runoff were slightly lower but significant when WEP was measured by the 10 labs (r = 0.56–0.86). Based on laboratory repeatability and water quality evaluation criteria, we recommend the following common protocol: 100:1 extraction ratio; 1-h shaking and centrifuge 10 min at 1500 x g (filter with Whatman #1 paper if necessary); and determining P by inductively coupled plasma–atomic emission spectrometry or colorimetric methods.

Sensitivity Analysis of Factors Influencing the Fate and Transport of Fecal Indicator Bacteria in Southern Lake Michigan
Authors: Schwab, D J, Thupaki, P, Phanikumar, M S Whitman, R L Nevers, M B Shively, D A
Affiliations: NOAA Great Lakes Environmental Research Laboratory (GLERL), 4840 S. State Rd., Ann Arbor, MI 48105, United States, Michigan State University, Department of Civil & Environmental Engineering , East Lansing, MI 48864, United States, USGS Great Lakes Science Center, Lake Michigan Ecological Research Station, Porter, IN 46304, United States
Source: Advances in Water ReSource:s (AGU), 2007

Abstract: To understand the factors that influence the fate and transport of fecal indicator bacteria (FIB) in the nearshore waters of the Great Lakes, we examined two southern Lake Michigan beaches (as well as the tributaries discharging into the lake in the vicinity of the beaches). A three-dimensional, ó-coordinate Princeton Ocean Model (POM) with a nested-grid was used to describe wind-driven circulation in Lake Michigan. A biological model coupled to the hydrodynamic and temperature fields in the lake was used to describe the observed FIB levels near the beaches. We report simulation results for the summers of 2004 and 2006. Inactivation of pathogens in the nearshore region is influenced by a complex set of factors including solar insolation, water temperature, settling of particulate matter, resuspension, turbulent diffusion, loading from tributaries etc. Efforts to systematically quantify the relative contributions of these complex and often inter-related processes are somewhat limited, especially for freshwater environments. Here we describe sensitivity analyses based on our numerical simulations with the objective of ranking the various processes involved in terms of their relative importance. We also examine the performance of different mathematical formulations of inactivation in order to identify their relative merits.

Sources of Phosphorus Lost from a Grazed Pasture Receiving Simulated Rainfall
Authors: R. W. McDowella,*, D. M. Nashb and F. Robertsonc
Affilliations: a AgResearch Limited, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand, b Victorian Dep. of Primary Industries–Ellinbank, RMB 2460 Hazeldean Road, Ellinbank, Victoria 3821, Australia and e-Water CRC, Univ. of Canberra, ACT 2601, Australia, c Victorian Dep. of Primary Industries–Hamilton, Mount Napier Road, Hamilton, Victoria 3300, Australia
Source: Jounral of Environmental Quality, 17 July 2007, 36:1281-1288

Abstract: Nutrients exported from grazing systems contribute to eutrophication of surface waters. In this study the contributions of soil, pasture-plants, and dung to P exports in overland flow were compared using simulated rainfall. The treatments were (i) grazed pasture-plants (isolated from soil by application of petrolatum to the soil surface), (ii) grazed pasture-plants and supporting soil, (iii) grazed pasture-plants and soil and treading, and (iv) grazed pasture-plants and soil and treading and dung. In general, dissolved reactive P (DRP) accounted for the majority of the P exported and P losses decreased in the order: treading and dung treatment › treading › pasture-plants and soil › pasture-plants. Very little dissolved organic P was lost in overland flow and the effects of treading diminished with time. Over a normal grazing cycle (30 d), the portion of P lost from pasture-plants was approximately half that lost from pasture-plants and soil, one-third that lost from treaded pasture-plants and soil, and one-quarter that lost from treaded pasture-plants, soil, and dung. The DRP in the pasture-plants treatment was approximately half that in the pasture-plants and soil treatment and suggests that a significant portion of the P exported from these systems is derived directly from pasture-plants. Due to higher proportions of particulate P (PP) in the treaded and dung treatments, DRP accounted for less of total P than in the pasture-plants and pasture-plants and soil treatments. Lower infiltration capacities probably caused by mechanical disaggregation at the soil surface are consistent with the higher proportions of PP in the treading treatments. These results were used to estimate P exports from a field trial site in Southland, New Zealand. The results suggested that P export attributable to fertilizer, dung, pasture-plants, and soil components were approximately 10, 30, 20, and 40%, respectively. These results suggest that since 90% of the P exports are derived from the soil–plant system and dung returns, managements to lessen P exports should continue to focus on maintaining soil P within the optimal range for pasture-plant production and maintaining soil surface properties that maximize infiltration and minimize overland flow.

Summer Cover Crops Reduce Atrazine Leaching to Shallow Groundwater in Southern Florida
Authors: Thomas L. Pottera,*, David D. Bosch^a, Hyun Joo^b, Bruce Schaffer ^c and Rafael Muñoz-Carpena^d
Affiliations: a USDA-ARS, Southeast Watershed Research Lab., P.O. Box 748, Tifton, GA 31793, b Dep. of Environmental and Molecular Toxicology, North Carolina State Univ., Raleigh, NC, c Tropical Research and Education Center, Univ. of Florida, Homestead, FL 33031, d Dep. of Agricultural and Biological Engineering, Univ. of Florida, Gainesville, FL. Mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture
Source: Journal of Environmental Quality, 17 July 2007, 36:1301-1309

Abstract: At Florida's southeastern tip, sweet corn (Zea Mays) is grown commercially during winter months. Most fields are treated with atrazine (6-chloro-N-ethyl-N'-[1-methylethyl]-1, 3,5-triazine-2,4-diamine). Hydrogeologic conditions indicate a potential for shallow groundwater contamination. This was investigated by measuring the parent compound and three degradates–DEA (6-chloro-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine), DIA (6-chloro-N-ethyl)-1, 3,5-triazine-2,4-diamine, and HA (6-hydroxy-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine)–in water samples collected beneath sweet corn plots treated annually with the herbicide. During the study, a potential mitigation measure (i.e., the use of a cover crop, Sunn Hemp [Crotalaria juncea L.], during summer fallow periods followed by chopping and turning the crop into soil before planting the next crop) was evaluated. Over 3.5 yr and production of four corn crops, groundwater monitoring indicated leaching of atrazine, DIA, and DEA, with DEA accounting for more than half of all residues in most samples. Predominance of DEA, which increased after the second atrazine application, was interpreted as an indication of rapid and extensive atrazine degradation in soil and indicated that an adapted community of atrazine degrading organisms had developed. A companion laboratory study found a sixfold increase in atrazine degradation rate in soil after three applications. Groundwater data also revealed that atrazine and degradates concentrations were significantly lower in samples collected beneath cover crop plots when compared with concentrations below fallow plots. Together, these findings demonstrated a relatively small although potentially significant risk for leaching of atrazine and its dealkylated degradates to groundwater and that the use of a cover crop like Sunn Hemp during summer months may be an effective mitigation measure.

Survival And Persistence of Bacteroidales Human And Ruminant Specific Fecal Markers and Occurrence with Fecal Pathogens
Author: Walters, Sarah P.
Source: Electronic Theses and Dissertations, January 18, 2007

Abstract: Aquatic fecal contamination from non-point sources impairs environmental health and serves as a vehicle for transmission of waterborne disease, resulting in economic losses worldwide. Accurate methods of diagnosing fecal pollution and its source are needed to prevent human exposure, remediate pollution, and reduce economic impacts. In order to obtain this goal, fecal indicator organisms should demonstrate persistence and survival profiles similar to fecal pathogens and be detected when pathogens are present. Molecular markers designed from Bacteroidales anaerobic fecal bacteria make good alternative indicator candidates because they identify fecal pollution sources and are not expected to grow in oxygenated environments. To further investigate the utility of these markers as indicators of fecal contamination and predictors of pathogen exposure, we evaluated co-occurrence of pathogenic E. coli O157:H7, Salmonella spp., and Campylobacter spp. with general, human, ruminant, and porcine-specific Bacteroidales molecular markers. We detected host-specific markers in samples where pathogens were present and found a significant correlation between presence of the ruminant markers and E. coli O157:H7, and the human markers and pathogenic Campylobacter spp. We examined growth and persistence of Bacteroidales organisms in aerobically incubated sewage influent using bromodeoxyuridine (BrdU) labeling and immunocapture. We identified growing Bacteroidales bacteria in BrdU-labeled DNA fractions after immunocapture with fluorescent fragment detection following a low, quantitative number of PCR cycles. We consistently detected growth of Bacteroidales organisms but were unable to detect growth of the human-specific Bacteroidales organisms using this method. We constructed microcosms to investigate how ambient light exposure affects survival and persistence of ruminant and human-specific Bacteroidales markers, relative to standard indicators. The ruminant-specific Bacteroidales markers displayed differential persistence and survival profiles in both light and dark incubations; this was not observed among the human-specific markers. In each microcosm, the standard indicators persisted and survived longer than any of the Bacteroidales host-specific markers. Host-specific Bacteroidales genetic markers show promise as an accurate, rapid, and reliable tool in health risk based analyses of fecal pollution. The molecular markers are detected when pathogens are present, persist less than 14 days in natural river water at 13°C, and the marker organisms do not proliferate in the environment.

Temporal and Spatial Trends in the Occurrence of Human and Veterinary Antibiotics in Aqueous and River Sediment Matrices
Authors: Sung-Chul Kim and Kenneth Carlson
Affiliations: Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, Colorado 80523-1372
Source: Environmental Science and Technology, December 5, 2006, 41 (1): 50 -57, 2007

Abstract: The occurrence of 15 antibiotics belonging to three different groups, tetracyclines (TCs), sulfonamides (SAs), and macrolides (MLs), mainly used to prevent or treat illness for humans and also to control disease or to promote the growth for animals was studied in aqueous and sediment matrices. The result of spatial and temporal statistical analysis revealed that measured concentrations of individual antibiotics were significantly different depending on sampling location and time periods for aqueous and sediment samples. High concentrations of human-used antibiotics were detected downstream of a wastewater treatment plant, and animal-used antibiotics were mainly found in a region with significant agricultural activity. Generally, the highest concentrations of antibiotics for both water and sediment samples were measured in winter indicating that low flow conditions and cold-water temperatures might enhance the persistence of these compounds. Furthermore, a pseudo-partitioning coefficient (P-PC) was introduced to provide a better understanding of the partitioning of antibiotics into the sediment. Different P-PC values were found depending on the sorption characteristics of the individual antibiotics. Sediment samples showed a greater detection frequency and a much higher concentration compared to aqueous samples taken at the same site. Since microorganism antibiotic resistance can develop in sediments, the importance of analyzing this matrix is underscored.

Tile Water Quality Following Liquid Swine Manure Application into Standing Corn
Authors: B. R. Ball Coelho, R. C. Roy (deceased), E. Topp and D. R. Lapen
Affiliations: Agriculture & Agri-Food Canada, Southern Crop Protection & Food Research Centre, 1391 Sandford Street, London, ON, Canada N5V 4T3, Agriculture & Agri-Food Canada, Southern Crop Protection & Food Research Centre, Delhi, ON, Canada, N4B 2W9, Agriculture & Agri-Food Canada, Eastern Cereal Oilseed Research Centre, 960 Carling Ave., Ottawa, ON K1A 0C6
Source: Journal of Environmental Quality, March 1, 2007, 36: 580-587

Abstract: The quality of water draining fields fertilized with liquid swine (Sus scrofa) manure (LSM) sidedressed into standing corn (Zea mays L.) at rates ranging from 0 to 94 m3 ha–1, either topdressed (TD) onto the surface, or injected (INJ) into the soil once annually for each of three consecutive years was evaluated. Liquid swine manure application rate was a critical driver of preferential flow of LSM to tile as detected by turbidity, concentrations of NH4+–N, dissolved reactive phosphorus (DRP), and the presence of enteric bacteria (Escherichia coli). Contaminant movement to drains occurred immediately after 75 and 94 m3 LSM ha–1 were injected (e.g., 2.5 mg DRP L–1, 3-yr average). With injection of 56 m3 ha–1 or less, drainage water was not turbid and concentrations of NH4+–N, DRP, and enteric bacteria were dramatically lower than with the higher rates, even when tiles flowed freely during manure application. Application method also affected tile water quality. With TD applications (37 and 56 m3 ha–1), nutrients and bacteria did not move to tiles at the time of application, but with rains that fell within 3 d after application, concentrations increased (e.g., 0.1 mg DRP L–1), although less than with INJ. Overall, sidedress injection rates that supplied adequate crop nutrients did not compromise drainage water quality.

Total Soil Carbon and Water Quality: An Implication for Carbon Sequestration
Authors: Gil Eshel, Pinchas Fine, and Michael J. Singer
Affiliations: Inst. of Soil, Water and Environ. Sciences ARO, The Volcani Center, Bet Dagan 50250, Israel, Dep. of Land, Air and Water Resources, Univ. of California, Davis, CA 95616
Source: Soil Science Society of American Journal, March 12, 2007, 41(6): 1366-1378

Abstract: Carbon sequestration in soil has been suggested as a means of reducing the rate of increase of atmospheric CO2. Most soil science research has been on soil organic carbon (SOC) sequestration but in arid and semiarid climates, soil inorganic carbon (SIC) may offer another option for C sequestration. A field study was conducted in Bakersfield, CA, to determine if irrigation water quality (fresh water [FW] vs. treated effluent [TE]) affected the distribution and amount of SIC and SOC in the upper 4 m of soil and parent material compared to a nonirrigated (NI) field. Significant carbonate depletions were found in the upper 2 m in both irrigated fields compared with the NI. Differences in carbonate content between irrigated fields were also related to soil texture. Total carbonate and clay-size carbonate were more abundant at the sites irrigated with TE than at the sites irrigated with FW, indicating that the TE had inhibited carbonate dissolution. Based on stable isotope analyses (13C and 18O) and radiocarbon dating, we estimated that irrigation for ›75 yr sequestered about 7.15 kg m–2 (4 m)–1 of SIC under FW and between 0.9 and 2.4 kg m–2 (4 m)–1 under TE, if carbonate dissolution is C sequestration. Adding C loss due to SOC decomposition to the SIC sequestration, the fields may be a source for 8.8 and 17.4 to 15.9 kg m–2 (4 m)–1 of C under FW and TE, respectively. This study provides some of the first evidence of how water quality affects the C budget in an arid region.

Water Quality Index: A Fuzzy River-Pollution Decision Support Expert System
Authors: Fuzhan Nasiri, Imran Maqsood, Gordon Huang, and Norma Fuller
Affiliations: Ph.D. Student, Faculty of Environmental Systems Engineering, Univ. of Regina, Regina SK, Canada (corresponding author). E-mail: nasiri2f@uregina.ca, Research Associate, Faculty of Environmental Systems Engineering, Univ. of Regina, Regina SK, Canada., Professor, Faculty of Environmental Systems Engineering, Univ. of Regina, Regina SK, Canada. E-mail: gordon.huang@uregina.ca, Assistant Professor, Dept. of Science, First Nations Univ. of Canada, Regina SK, Canada. E
Source: Journal of Water Resource Planning and Management, March/April 2007, 133(2): 95-105

Abstract: Water quality management policies, which are proposed to prevent, control, or treat environmental problems related to quality of water, are broad and complex issues. We have various types of water resources, different water uses, and a lot of decision parameters with several levels of decision makers involved. Moreover, there are a lot of strategies and technologies available to be applied for water quality management and so environmental decision makers are required to evaluate and prioritize them in order to choose the best possible plan for each particular problem. To provide a comprehensive but easy to use tool in the assessment and evaluation of water quality policies, the concept of water quality index (WQI) has been developed. Due to the abovementioned complexities, to get this index, there is a need for a methodology to not only structure and identify information relevant to the problem but also to help users reach a decision. Designing a multiple-attribute decision support expert system, which makes expert knowledge available to nonexpert users, can do this. In doing so, we may encounter qualitative or linguistic assessments in the index making process. Thus, fuzzy set theory can be applied to recognize this inherent fuzziness of such a process. Briefly, in this study we propose a fuzzy multiple-attribute decision support expert system to compute the water quality index and to provide an outline for the prioritization of alternative plans based on the amount of improvements in WQI. At the end, applicability and usefulness of the proposed methodology is revealed by a case study.

Wavelet Analysis of Hydrological and Water Quality Signals in an Agricultural Watershed
Author: Shujiang Kang^a and Henry Lin
Affiliaiton: aPennsylvania State University, Department of Crop and Soil Sciences, 116 ASI, University Park, PA 16802, United States
Source: Journal of Hydrology, 15 May 2007, 338(1-2):1-14

Abstract: Studying temporal patterns of hydrology and water quality can assist in understanding hydrological processes, improving hydrological modeling, and water quality monitoring. Using wavelet analysis, we analyzed temporal patterns of three hydrological signals (precipitation, stream flow, and well water level) for three periods (15 years, 3 year, and a hydrological year). For three unevenly sampled water quality signals (nitrate, chloride, and sodium), the weighted wavelet Z-transform (WWZ) method was employed. The results showed that the wavelet analysis of hydrological signals showed advantages of detecting detailed temporal patterns compared to the classical Fourier analysis. No strong temporal pattern of precipitation was found for all three periods. For the 15 years’ continual monitoring datasets, strong consistent annual temporal pattern of well water level and an intermittent annual temporal pattern of stream flow were observed. For the relative short-time periods (three years and a hydrological year), strong seasonal patterns of stream flow and well water level were noticed. Using the WWZ method, seasonal patterns of the three stream water quality indicators can be associated with their seasonal shifts. Nitrate concentration showed stronger temporal patterns than chloride and sodium over longer time periods (15 and 3 years). In a hydrological year, temporal patterns of nitrate, chloride, and sodium shared some similarities as well as dissimilarities, as can be explained by their different transport pathways and sources. Sodium and chloride peak concentrations in the winter season were captured by the wavelet analysis. It is concluded that wavelet analysis can be a useful tool to analyze detailed temporal patterns of non-stationary hydrological and water quality signals over different temporal scales.

Wetland restoration at the Society for Ecological Restoration International Conference in Zaragoza, Spain: Cost and Pollutant Removal of Storm-Water Treatment Practices
Authors: Peter T. Weiss,¹ M.ASCE; John S. Gulliver,² F.ASCE; and Andrew J. Erickson,³ S.M.ASCE
Affiliations: ¹Associate Professor, Dept. of Civil Engineering, Valparaiso Univ., Valparaiso, IN 46383 (corresponding author), ²Joseph T. and Rose S. Ling Professor and Head, Dept. of Civil Engineering, Univ. of Minnesota, Minneapolis, MN 55414. , ³Graduate Student, St. Anthony Falls Laboratory, Dept. of Civil Engineering, Univ. of Minnesota, 3rd Ave. SE, Minneapolis, MN 55414.
Source: Journal of Water Resource Planning and Management, May/June 2007, 133(3):218-229

Abstract: Six storm-water best management practices (BMPs) for treating urban rainwater runoff were evaluated for cost and effectiveness in removing suspended sediments and total phosphorus. Construction and annual operating and maintenance (O and M) cost data were collected and analyzed for dry extended detention basins, wet basins, sand filters, constructed wetlands, bioretention filters, and infiltration trenches using literature that reported on existing storm-water BMP sites across the United States. After statistical analysis on historical values of inflation and bond yields, the annual O and M costs were converted to a present worth based on a 20-year life and added to the construction cost. The total present cost of each storm-water BMP with the 67% confidence interval was reported as a function of the water quality design volume, again with a 67% confidence interval. Finally, the mass of total suspended solids and total phosphorus removed over the 20-year life was estimated as a function of the water quality volume. For the six storm-water BMPs investigated, results show that, ignoring land costs, constructed wetlands have been the least expensive to construct and maintain if appropriate land is available. However, since wetlands typically require more land area to be effective, land acquisition costs may result in wetlands being significantly more expensive than other storm-water BMPs that require less area. The results can be used by planners and designers to estimate both the total cost of installing a storm-water BMP and the corresponding total suspended solids and total phosphorus removal.

2006

Applying Fluorescence Based Technology to the Recovery and Isolation of Cryptosporidium and Giardia from Industrial Wastewater Streams
Author: Ferrari, BC; Stoner, K; Bergquist, PL
Affiliation: Department of Chemistry and Biomolecular Sciences, Environmental Biotechnology CRC and Biotechnology Research Institute, Macquarie University
Source: Water Research Vol. 40, no. 3, pp. 541-548. 2006.

Abstract: As increasing water shortages continue, water re-use is posing new challenges with treated wastewater becoming a significant source of non-potable water. Rapid detection strategies that target waterborne pathogens of concern to industry are gaining importance in the assessment of water quality. This study reports on the ability to recover spiked Cryptosporidium and Giardia from a variety of industrial wastewater streams of varied water quality. Incorporation of an internal quality control used commonly in finished water- enabled quantitative assessments of pathogen loads and we describe successful analysis of pre- and part-treated wastewater samples from four industrial sites. The method used combined calcium carbonate flocculation followed by flow cytometry and epifluorescence microscopy. Our focus will now aim at characterising the ambient parasites isolated from industrial wastewater with the objective of developing a suite of highly specific platform detection technologies targeted to industrial needs.

Assessment of Sediment Yields for a Mixed-landuse Great Lakes Watershed: Lessons from Field Measurements and Modeling
Authors: Shreeram Inamdar and Aleksey Naumov, Great Lakes Center and the Department of Geography, SUNY Buffalo State College, 1300 Elmwood Avenue, Buffalo, New York, 14222
Source: Journal of Great Lakes Research, International Association of Great Lakes Research, 2006, 32 (3): 471-488

Abstract: The Soil Water Assessment Tool (SWAT) was implemented to determine annual sediment yields and critical source areas of erosion for the Buffalo River Watershed. Model calibrations were performed by comparing simulated streamflow discharge and sediment concentrations against measured values. Monte-Carlo simulations were performed to identify the most sensitive parameters and the “best-fit” parameter ranges. This study especially highlighted the importance of snow parameters, which, previously had not been identified as sensitive for model simulations. The cover (C) and practice (P) values for croplands had to be reduced considerably from default model values to constrain simulated sediment yields within the observed data range. The model did not simulate an ice-scour event which generated a substantial amount of sediment. The average annual sediment yield simulated by SWAT for the Buffalo River watershed (108,593 ha) amounted to 0.8 tons/ha/yr. The Cazenovia Creek subwatershed contributed the largest portion (45%) of the total sediment yield from the Buffalo River watershed. We attribute the higher sediment yields from Cazenovia Creek to the greater proportion of steep slopes in this subwatershed. The accuracy and reliability of SWAT sediment predictions at the small watershed (second order or less) and storm-event scales will depend on the accuracy of input information, especially the resolution of the landuse-landcover (LULC) layer, the number of rainfall stations used in simulations, and the number of internal sites against which the model has been calibrated.

Detection of E. coli in Water Using Semi-conducting Polymeric Thin Film Sensor
Authors: Vivechana Dixit, Jagdish C. Tewari, and Bindu S. Sharma
Source: School of Chemical Engineering and Department of Biological Sciences, Purdue University, West Lafayette, IN, USA Department of Physics, Institute of Basic Science, Agra University, Agra, India, January 2006

Abstract: This paper describes the application of semi-conducting polyaniline doped with Fe–Al vacuum deposited thin film as a sensor for the determination of Escherichia coli (E. coli) cells in the liquid medium. The presence of E. coli as a bacterial contamination in water was detected based on a change in conductivity due to redox reaction at the film surface.

Development of Goose- and Duck-Specific DNA Markers to Determine Sources of Escherichia coli in Waterways
Authors Matthew J. Hamilton,1,2 Tao Yan,2 and Michael J. Sadowsky1,2,3
Affiliation: Department of Microbiology,1 BioTechnology Institute,2 Department of Soil, Water, and Climate, University of Minnesota, St. Paul, Minnesota 551083
Source: Applied and Environmental Microbiology, June 2006, 72 (6): 4012-40196

Abstract: The contamination of waterways with fecal material is a persistent threat to public health. Identification of the sources of fecal contamination is a vital component for abatement strategies and for determination of total maximum daily loads. While phenotypic and genotypic techniques have been used to determine potential sources of fecal bacteria in surface waters, most methods require construction of large known-source libraries, and they often fail to adequately differentiate among environmental isolates originating from different animal sources. In this study, we used pooled genomic tester and driver DNAs in suppression subtractive hybridizations to enrich for host source-specific DNA markers for Escherichia coli originating from locally isolated geese. Seven markers were identified. When used as probes in colony hybridization studies, the combined marker DNAs identified 76% of the goose isolates tested and cross-hybridized, on average, with 5% of the human E. coli strains and with less than 10% of the strains obtained from other animal hosts. In addition, the combined probes identified 73% of the duck isolates examined, suggesting that they may be useful for determining the contribution of waterfowl to fecal contamination. However, the hybridization probes reacted mainly with E. coli isolates obtained from geese in the upper midwestern United States, indicating that there is regional specificity of the markers identified. Coupled with high-throughput, automated macro- and microarray screening, these markers may provide a quantitative, cost-effective, and accurate library-independent method for determining the sources of genetically diverse E. coli strains for use in source-tracking studies. However, future efforts to generate DNA markers specific for E. coli must include isolates obtained from geographically diverse animal hosts.

Distribution of Heavy Metals in Sediments of the Detroit River
Authors: Ewa Szalinska, Ken G. Drouillard, Brian Fryer and G. Douglas Haffner
Affiliations: Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, N9B 3P4 and Canada; Institute of Water Supply and Environmental Protection, Cracow University of Technology, ul.Warszawska 24, 31-155 Cracow and Poland
Source: Journal of Great Lakes Research, International Association of Great Lakes Research, 2006, 32 (3): 442-454.

Abstract: The spatial distribution of 17 metals in the sediments of the Detroit River was established using metal concentrations from a river-wide survey. The survey (1999) was based on a stratified random sampling design that divided the river into upper, middle, and lower reaches and subsequently into U.S. and Canadian sides of the river. Results based on strong extraction, using concentrated acids, revealed that the Lowest Effect Level (LEL) for As, Cd, Cu, and Hg was exceeded at more than 75% of sampling sites and the Severe Effect Level (SEL) for As at 16.2% of sites. Most of the metals were homogenously distributed throughout reaches of the river, although sites with elevated concentrations were localized mainly along the middle and lower reaches as a result of a pattern of contamination sources and geographic complexity of the river, especially a spatial/temporal variability in water flow. A comparison of the results of a strong to a weak extraction (cold 5% acetic acid, to assess metal bioavailability) revealed two groups of sediment type. The first group with a “high” weak/strong ratio (bioavailable metals; about 1 for Ca, Mg, Na and from 0.6 to 0.4 for the rest of metals) was observed at sites with low flow velocities below 0.4 m s–1. The “low” ratio (non-bioavailable metals; 0.25 for Ca, Mg, Na and from 0.15 to 0.05 for other metals) was observed at sites with flow velocities greater than 0.6 m s–1. The data indicate that the sediment conditions, dependent on flow distribution, regulate not only the distribution of heavy metals but also can regulate metal bioavailability.

Environmental Implications of Municipal Solid Waste-Derived Ethanol
Authors: Youssouf Kalogo, Shiva Habibi, Heather L. MacLean, and Satish V. Joshi
Affiliations: Department of Civil Engineering, University of Toronto, 35 St. George Street, Toronto, Ontario, M5S 1A4, Canada, and Department of Agricultural Economics, Michigan State University, 301C Agricultural Hall, East Lansing, Michigan 48864
Source: Environmental Science and Technology, December 2, 2006, 41 (1): 35 -41, 2007

Abstract: We model a municipal solid waste (MSW)-to-ethanol facility that employs dilute acid hydrolysis and gravity pressure vessel technology and estimate life cycle energy use and air emissions. We compare our results, assuming the ethanol is utilized as E85 (blended with 15% gasoline) in a light-duty vehicle, with extant life cycle assessments of gasoline, corn-ethanol, and energy crop-cellulosic-ethanol fueled vehicles. We also compare MSW-ethanol production, as a waste management alternative, with landfilling with gas recovery options. We find that the life cycle total energy use per vehicle mile traveled for MSW-ethanol is less than that of corn-ethanol and cellulosic-ethanol; and energy use from petroleum sources for MSW-ethanol is lower than for the other fuels. MSW-ethanol use in vehicles reduces net greenhouse gas (GHG) emissions by 65% compared to gasoline, and by 58% when compared to corn-ethanol. Relative GHG performance with respect to cellulosic ethanol depends on whether MSW classification is included or not. Converting MSW to ethanol will result in net fossil energy savings of 397-1830 MJ/MT MSW compared to net fossil energy consumption of 177-577 MJ/MT MSW for landfilling. However, landfilling with LFG recovery either for flaring or for electricity production results in greater reductions in GHG emissions compared to MSW-to-ethanol conversion.

Evaluation of Novel Fluorogenic Substrates for the Detection of Glycosidases in Escherichia coli and Enterococci
Authors: J.D. Perry, A.L. James, K.A. Morris, M. Oliver, K.F. Chilvers, R.H. Reed and F.K. Gould
Source: Journal of Applied Microbiology, November 2006, 101 (5): 977

Abstract: Enzyme substrates based on 4-methylumbelliferone are widely used for the detection of Escherichia coli and enterococci in water, by detection of -glucuronidase and ß-glucosidase activity respectively. This study aimed to synthesize and evaluate novel umbelliferone-based substrates with improved sensitivity for these two enzymes.

A novel ß-glucuronide derivative based on 6-chloro-4-methylumbelliferone (CMUG) was synthesized and compared with 4-methylumbelliferyl-ß-d-glucuronide (MUG) using 42 strains of E. coli in a modified membrane lauryl sulfate broth. Over 7 h of incubation, the fluorescence generated from the hydrolysis of CMUG by E. coli was over twice that from MUG, and all of the 38 glucuronidase-positive strains generated a higher fluorescence with CMUG compared with MUG. Neither substrate caused inhibition of bacterial growth in any of the tested strains. Four ß-glucosidase substrates were also synthesized and evaluated in comparison with 4-methylumbelliferyl-ß-d-glucoside (MU-GLU) using 42 strains of enterococci in glucose azide broth. The four substrates comprised ß-glucoside derivatives of umbelliferone-3-carboxylic acid and its methyl, ethyl and benzyl esters. Glucosides of the methyl, ethyl and benzyl esters of umbelliferone-3-carboxylic acid were found to be superior to MU-GLU for the detection of enterococci, especially after 18 h of incubation, while umbelliferone-3-carboxylic acid-ß-d-glucoside was inferior. However, the variability in detectable ß-glucosidase activity among the different strains of enterococci in short-term assays using the three carboxylate esters (7 h incubation) may compromise their use for rapid detection and enumeration of these faecal indicator bacteria.

The ß-glucuronidase substrate CMUG appears to be a more promising detection system than the various ß-glucosidase substrates tested.

The novel substrate CMUG showed enhanced sensitivity for the detection of ß-glucuronidase-producing bacteria such as E. coli, with a clear potential for application in rapid assays for the detection of this indicator organism in natural water and other environmental samples.

Examination of the Watershed-Wide Distribution of Escherichia coli along Southern Lake Michigan: an Integrated Approach
Authors: Richard L. Whitman,* Meredith B. Nevers, and Muruleedhara N. Byappanahalli
Affiliation: U.S. Geological Survey, Great Lakes Science Center, 1100 N. Mineral Springs Road, Porter, Indiana 46304
Source: Applied and Environmental Microbiology, November 2006, 72 (11): 7301-7310

Abstract: Recent research has highlighted the occurrence of Escherichia coli in natural habitats not directly influenced by sewage inputs. Most studies on E. coli in recreational water typically focus on discernible sources (e.g., effluent discharge and runoff) and fall short of integrating riparian, near shore, onshore, and outfall sources. An integrated “beachshed” approach that links E. coli inputs and interactions would be helpful to understand the difference between background loading and sewage pollution; to develop more accurate predictive models; and to understand the differences between potential, net, and apparent culturable E. coli. The objective of this study was to examine the interrelatedness of E. coli occurrence from various coastal watershed components along southern Lake Michigan. The study shows that once established in forest soil, E. coli can persist throughout the year, potentially acting as a continuous non-point source of E. coli to nearby streams. Year-round background stream loading of E. coli can influence beach water quality. E. coli is present in highly variable counts in beach sand to depths just below the water table and to distances at least 5 m inland from the shore, providing a large potential area of input to beach water. In summary, E. coli in the fluvial-lacustrine system may be stored in forest soils, sediments surrounding springs, bank seeps, stream margins and pools, foreshore sand, and surface groundwater. While rainfall events may increase E. coli counts in the foreshore sand and lake water, concentrations quickly decline to pre-rain concentrations. Onshore winds cause an increase in E. coli in shallow nearshore water, likely resulting from resuspension of E. coli-laden beach sand. When examining indicator bacteria source, flux, and context, the entire “beachshed” as a dynamic interacting system should be considered.

Monitoring Pollutants in Highway Runoff
Source: Water and Environment Journal, December 2006, 20 (4): 287
Authors: B. Crabtree, F. Moy, M. Whitehead & A. Roe

Abstract: Highway surface runoff discharges may contain pollutants that have accumulated on the carriageway, particularly following periods of dry weather. The Highways Agency, in association with the Environment Agency, commissioned a 5-year study in 1997 to collect data to improve the understanding of pollutants in highway runoff and the treatment efficiency of drainage systems. The study involved the monitoring of nonurban highway drainage at six sites, each for a minimum of 1 year. The results have been used to identify ranges of pollutant concentrations in highway runoff, relationships between runoff concentrations/loads and both highway and environmental factors, drainage system treatment efficiencies, and impacts on receiving waters. This paper describes the methods used for runoff monitoring, the results obtained to characterise pollutants in highway runoff, and the measured pollutant removal efficiency of a number of drainage system types.

Phosphorus Concentrations and Loads in Runoff Water Under Crop Production
Authors: He, Z L; Zhang, M K; Stoffella, P J; Yang, X E; Banks, D J
Affiliations: Zhejian University, College of Natural Resource and Environmental Science, Hangzhou, China (CHN), University of Florida at Fort Pierce, United States (USA)
Source: Soil Science Society of America Journal, October 2006, 70 (5): 1807-1816 http://soil.scijournals.org.proxy.lib.umich.edu/
ISSN: 1435-0661, 0361-5995

Abstract Transport of phosphorus (P) through surface runoff from agriculture is suspected to contribute to the eutrophication of surface waters in South Florida and elsewhere. There is minimal quantitative information on the concentrations and loads of various P forms in surface runoff water on a field-scale. The objective of this study was to evaluate the annual loads of various P forms in runoff water from citrus and vegetable crop production systems in sandy soil regions in Florida and their relations to soil P status, fertilizer P input, and environmental conditions. Eleven field sites (four on vegetable farms and seven in citrus groves) were selected for this monitoring study over a 2-yr period. The concentrations of total P (TP) in the runoff water samples varied widely from 0.01 to 22.74 mg L (super -1) , with approximately half of the samples having the TP over 1 mg L (super -1) . Eighty-three percent of the samples had orthophosphate (PO (sub 4) -P) higher than 0.02 mg L (super -1) . The mean proportion of total dissolved P (TDP) in the TP was higher than that of the total particulate P (TPP). The TDP constituted the major proportion of P in runoff water from most of the sites. The PO (sub 4) -P accounted for approximately 64% of the TDP. The annual median concentrations of various P forms in the runoff water varied spatially and temporally and were correlated with total and labile P in the soils (water-P, Olsen-P, Mehlich 1-P, and Mehlich 3-P) as well as fertilizer P rate. The vegetable farms had higher concentrations of P in the runoff water than citrus groves due to their more severe soil erosion and higher fertilizer P input, which resulted in higher soil P accumulation and availability. The annual loads of TP, TDP, and PO (sub 4) -P varied among the field sites and between the 2 yr. The TP loads were significantly correlated with soil labile P estimated by the four extraction procedures, but the Olsen-P was best related to runoff P. Runoff P concentrations and the annual discharge rate accounted for 55 to 64% of the variance in the annual P loads. These results indicate that P transport through surface runoff from agriculture is affected by soil P status and water management, and merits attention in the development of best management practices.

Surface Corrections for Remote Sensing Reflectance in Case 2 Waters of Lake Superior
Authors: Yuhu Yan and Michael Sydor, 1Water Resources Science, University of Minnesota, St. Paul, Minnesota, 55108; Department of Physics, University of Minnesota Duluth, Duluth, Minnesota, 55812
Source: Journal of Great Lakes Research, International Association of Great Lakes Research, 2006, 32 (3): 407-414

Abstract: We establish the average wavelength dependence for rough-surface reflectance Srs(λ) in Lake Superior and determine its magnitude at any individual site by extrapolating the total reflectance or raw remote sensing reflectance RrsT(λ) measured at the surface to the asymptotic limit of zero scattering where Srs(λ) λ RrsT(λ). The results show that Srs(λ) differs from the flat-surface Fresnel reflectance of sky radiance used in standard determination of the remote sensing reflectance Rrs(λ) attributed to the scattering of light by particles and molecules in bulk water. In waters containing colored dissolved organic matter (CDOM), Rrs(λ) can be very low and radiometric measurements at ground level can often lead to negative estimates of Rrs(λ) if we assume simple mirror-like reflectance of the sky radiance as the basis for correcting radiometric data for surface reflectance. We examine the differences between Fresnel reflectance and Srs(λ) and estimate the ratio of the concentrations of CDOM versus suspended particles that could produce negative values of Rrs(λ) if assume Fresnel reflectance in calculation of Rrs(λ).

2005

Assessment of Statistical Methods Used in Library-based Approaches to Microbial Source Tracking
Author: Ritter, Kerry J; Carruthers, Ethan A; Carson, CAndrew; Ellender, RD; Harwood, Valerie J; Kingsley, Kyle S; Nakatsu, Cindy H; Sadowsky, Michael J; Shear, Brian L; West, Brian R; Whitlock, John E; Wiggins, Bruce A; Wilbur, Jayson D
Source: Annual report. Southern California Coastal Water Research Project no. 2003-2004, [np]. 2005.

Abstract: Several commonly used statistical methods for fingerprint identification in microbial source tracking (MST) were examined to assess the effectiveness of pattern-matching algorithms to correctly identify sources. Although numerous statistical methods have been employed for source identification, no widespread consensus exists as to which is most appropriate. A large-scale comparison of several MST methods, using identical fecal sources, presented a unique opportunity to assess the utility of several popular statistical methods. These included discriminant analysis, nearest neighbor analysis, maximum similarity and average similarity, along with several measures of distance or similarity. Threshold criteria for excluding uncertain or poorly matched isolates from final analysis were also examined for their ability to reduce false positives and increase prediction success. Six independent libraries used in the study were constructed from indicator bacteria isolated from fecal materials of humans, seagulls, cows and dogs. Three of these libraries were constructed using the rep-PCR technique and three relied on antibiotic resistance analysis (ARA). Five of the libraries were constructed using Escherichia coli and one using Enterococcus spp. (ARA). Overall, the outcome of this study suggests a high degree of variability across statistical methods. Despite large differences in correct classification rates among the statistical methods, no single statistical approach emerged as superior. Thresholds failed to consistently increase rates of correct classification and improvement was often associated with substantial effective sample size reduction. Recommendations are provided to aid in selecting appropriate analyses for these types of data.

Die-off of Pathogenic E. coli O157:H7 in Sewage Contaminated Waters
Author: Easton, JH; Gauthier, JJ; Lalor, MM; Pitt, RE
Affiliation: Southern Methodist University
Source: Journal of the American Water Resources Association Vol. 41, no. 5, pp. 1187-1193. Oct 2005.

Abstract: E. coli O157:H7 is a pathogen that can be present in sewage contaminated waters. This organism poses a health risk for humans who come in contact with these waters via drinking, swimming, or shellfish consumption. A risk assessment model is needed to evaluate or quantify this risk. One possibility is the use of a computer model to simulate the fate and transport of E. coli O157:H7 downstream from a discharge point [e.g., a separate sanitary sewer overflow (SSO)]. However, this computer model would require input data regarding characteristics of this organism, which have not been previously available. One necessary input parameter is the rate at which die off of this organism occurs in a stream or river environment. Several studies were conducted to evaluate the die-off rate of E. coli O157:H7 in an SSO impacted stream. Indicator bacteria (total coliforms, E. coli, and enterococci) were evaluated simultaneously. The results suggest that E. coli O157:H7 is not persistent - decay rates are high relative to the indicator bacteria. However, the decay plots suggest a biphasic response: initial decay is rapid, followed by an attenuated, slower decay. Hence traditional simulation methods using a single, first-order decay rate may be inaccurate.

Processes for Managing Pathogens
Author: Godfree, A; Farrell, J
Affiliation: Public Health Section, United Utilities Water, UK
Source: Journal of Environmental Quality Vol. 34, no. 1, pp. 105-113. Jan-Feb 2005.

Abstract: Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles.

Quantifying the Dimensions of Nanoscale Organic Surface Layers in Natural Waters
Authors: C. T. Gibson, Ian J. Turner, Clive J. Roberts, and J. R. Lead
Affiliations: School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, Biology Sciences Research Group, School of Education, Health and Science, University of Derby, Derby DE22 1GB, and Laboratory of Biophysics and Surface Analysis, School of Pharmacy, The University of Nottingham, University Park NG7 2RD, United Kingdom
Source: Environmental Science Technology, January 13, 2007

Abstract: Nanoscale surface films are known to develop on surfaces exposed to natural waters and have potential impacts on many environmental processes. A new method using atomic force microscopy is presented which physically removes the developed film in a defined area and then quantifies the difference in height between the film and the area where the film has been removed. The difference gives the absolute thickness of the surface film, which has not previously been measured. Suwannee River humic acid was exposed to substrates, and the surface film thickness as a function of pH and exposure time was measured. Discrete and very small colloids in the range 1-5 nm were observed as expected, and these sat on a coherent surface film, not the original mica substrate. Low pH values of 2 gave rise to relatively thick surface films of about 3 nm, although these films were not continuous at higher pH values. At pH 4.8, the film thickness increased with exposure time up to about 5 h and did not subsequently increase. The maximum film thickness measured was about 1 nm at that pH. The method is applicable to the measurement of many environmental surfaces, although resolution will depend on the substrate and film roughness.

Quantifying the Impact of Runoff Events on Microbiological Contaminant Concentrations Entering Surface Drinking Source Waters
Author: Signor, RS; Roser, DJ; Ashbolt, NJ; Ball, JE
Affiliation: School of Civil and Environmental Engineering, the University of New South Wales
Source: Journal of Water and Health Vol. 3, no. 4, pp. 453-468. Dec 2005.

Abstract: Concentrations of microbiological contaminants in streams increase during rainfall-induced higher flow 'event' periods as compared to 'baseflow' conditions. If the stream feeds a drinking water reservoir, such periods of heightened pathogen loads may pose a challenge to the water treatment plant and subsequently a health concern to water consumers downstream. In order to manage this risk, it is desirable to first quantify the differences in surface water quality between baseflow and event conditions. The Event Mean Concentration (EMC) is a flow-weighted average concentration of a contaminant over the duration of a single event, proposed here as a standard parameter for quantifying the net effect of events on microbial water quality. Application of the EMC concept was assessed using flow and quality data for several events from an urbanised catchment. Expected mean EMCs were significantly larger than expected mean baseflow concentrations (p-value less than or equal to 0.012) for three microbial agents - Escherichia coli (13,000 [n = 7] v. 610 [n = 16] mpn/100 ml), Cryptosporidium (234 [n = 6] v. 51 [n = 16] oocysts/10 litres) and Campylobacter (48 [n = 5] v. 2.1 [n = 16] mpn/100 ml). These parameter estimates were complemented by estimating data variability and uncertainty in the form of second-order random variables. As such the results are in a format appropriate for potential use as components in probabilistic risk assessments evaluating the effect runoff events have on drinking water quality.

Removal of Heavy Metals from Storm and Surface Water by Slow Sand Filtration: The Importance of Speciation
Author: Muhammad, N; Parr, J; Smith, MD; Wheatley, AD
Affiliation: Department of Microbiology, Miami University
Source: Urban Water Journal Vol. 2, no. 1, pp. 33-37. Mar 2005.

Abstract: The removal of heavy metals from storm and surface waters by slow sand filtration is described. The importance of speciation as a technique for exploring and improving the mechanisms of removal is identified. Laboratory-scale slow sand filters operating at conventional flow rate and depth were shown to be able to reduce concentrations of selected heavy metals (Cu, Cr, Pb and Cd) found in road runoff, surface water and sewage effluents to drinking water standard. Nitrogen, volatile solids and modified Stover speciation were used to differentiate between the potential mechanisms of removal, i.e. active biomass, organic adsorption and simple adsorption or precipitation on the surface of the sand. The data presented show that adsorption via organic ligands was the predominant mechanism for metal removal at the surface of the filter but chemical adsorption was the more important deeper in the filter. In the lower layers the adsorbed metals were more easily exchanged than the organically bound metals. The precise chemical ligands were not identified and varied from metal to metal. The most important operational factors affecting performance were therefore the concentration of organic matter, filter depth and the flow velocity.

Review of Factors Affecting Microbial Survival in Groundwater
Author: John, DE; Rose, JB
Affiliation: College of Marine Science, University of South Florida
Source: Environmental Science & Technology Vol. 39, no. 19, pp. 7345-7356. 1 Oct 2005

Abstract: This review quantitatively examines a number of published studies that evaluated survival and inactivation of public-health-related microorganisms in groundwater. Information from reviewed literature is used to express microbial inactivation in terms of log sub (10) decline per day for comparison to other studies and organisms. The geometric mean value for inactivation rates for coliphage, poliovirus, echovirus, coliform bacteria, enterococci, and Salmonella spp. were similar at approximately 0.07-0.1 log sub(10) day super(-1), while geometric mean inactivation rates for hepatitis A virus, coxsackievirus, and phage PRD-1 were somewhat less at 0.02-0.04 log sub(10) day super(-1). Viruses show a temperature dependency with greater inactivation at greater temperatures; however this occurs largely at temperatures greater than 20 degree C. Coliform bacteria die-off in groundwater does not show the temperature dependency that viruses show, likely indicating a complex interplay of inactivation and reproduction subject to influences from native groundwater organisms, temperature, and water chemistry. The presence of native microorganisms seems to negatively impact E. coli survival more so than viruses, but in most cases, nonsterile conditions led to a greater inactivation for viruses also. The effect of attachment to solid surfaces appears to be virus-type-dependent, with PRD-1 more rapidly inactivated as a result of attachment and hepatitis A and poliovirus survival prolonged when attached.

Validity of the Indicator Organism Paradigm for Pathogen Reduction in Reclaimed Water and Public Health Protection
Author: Harwood, Valerie J; Levine, Audrey D; Scott, Troy M; Chivukula, Vasanta; Lukasik, Jerzy; Farrah, Samuel R; Rose, Joan B
Affiliation: Department of Biology, SCA 110, University of South Florida
Source: Applied and Environmental Microbiology Vol. 71, no. 6, pp. 3163-3170. Jun 2005

Abstract: The validity of using indicator organisms (total and fecal coliforms, enterococci, Clostridium perfringens, and F-specific coliphages) to predict the presence or absence of pathogens (infectious enteric viruses, Cryptosporidium, and Giardia) was tested at six wastewater reclamation facilities. Multiple samplings conducted at each facility over a 1-year period. Larger sample volumes for indicators (0.2 to 0.4 liters) and pathogens (30 to 100 liters) resulted in more sensitive detection limits than are typical of routine monitoring. Microorganisms were detected in disinfected effluent samples at the following frequencies: total coliforms, 63%; fecal coliforms, 27%; enterococci, 27%; C. perfringens, 61%; F-specific coliphages, similar to 40%; and enteric viruses, 31%. Cryptosporidium oocysts and Giardia cysts were detected in 70% and 80%, respectively, of reclaimed water samples. Viable Cryptosporidium, based on cell culture infectivity assays, was detected in 20% of the reclaimed water samples. No strong correlation was found for any indicator-pathogen combination. When data for all indicators were tested using discriminant analysis, the presence/absence patterns for Giardia cysts, Cryptosporidium oocysts, infectious Cryptosporidium, and infectious enteric viruses were predicted for over 71% of disinfected effluents. The failure of measurements of single indicator organism to correlate with pathogens suggests that public health is not adequately protected by simple monitoring schemes based on detection of a single indicator, particularly at the detection limits routinely employed. Monitoring a suite of indicator organisms in reclaimed effluent is more likely to be predictive of the presence of certain pathogens, and a need for additional pathogen monitoring in reclaimed water in order to protect public health is suggested by this study.

Waterborne Pathogen Detection by Use of Oligonucleotide-Based Microarrays
Author: Maynard, Christine; Berthiaume, Frederic; Lemarchand, Karine; Harel, Josee; Payment, Pierre; Bayardelle, Paul; Masson, Luke; Brousseau, Roland
Affiliation: National Research Council of Canada
Source: Applied and Environmental Microbiology. 71, no. 12, pp. 8548-8557. Dec 2005.

Abstract: A small-oligonucleotide microarray prototype was designed with probes specific for the universal 16S rRNA and cpn60 genes of several pathogens that are usually encountered in wastewaters. In addition to these two targets, wecE-specific oligonucleotide probes were included in the microarray to enhance its discriminating power within the Enterobacteriaceae family. Universal PCR primers were used to amplify variable regions of 16S rRNA, cpn60, and wecE genes directly in Escherichia coli and Salmonella enterica serovar Typhimurium genomic DNA mixtures (binary); E. coli, S. enterica serovar Typhimurium, and Yersinia enterocolitica genomic DNA mixtures (ternary); or wastewater total DNA. Amplified products were fluorescently labeled and hybridized on the prototype chip. The detection sensitivity for S. enterica serovar Typhimurium was estimated to be on the order of 0.1% (10 super (4) S. enterica genomes) of the total DNA for the combination of PCR followed by microarray hybridization. The sensitivity of the prototype could be increased by hybridizing amplicons generated by PCR targeting genes specific for a bacterial subgroup, such as wecE genes, instead of universal taxonomic amplicons. However, there was evidence of PCR bias affecting the detection limits of a given pathogen as increasing amounts of a different pathogen were spiked into the test samples. These results demonstrate the feasibility of using DNA microarrays in the detection of waterborne pathogens within mixed populations but also raise the problem of PCR bias in such experiments.

2004

Dispersion and Transport of Cryptosporidium Oocysts from Fecal Pats under Simulated Rainfall Events
Author: Davies, CM; Ferguson, CM; Kaucner, C; Krogh, M; Altavilla, N; Deere, DA; Ashbolt, NJ
Affiliation: Centre for Water and Waste Technology, School of Civil and Environmental Engineering, University of New South Wales
Source: Applied and Environmental Microbiology Vol. 70, no. 2, pp. 1151-1159. Feb 2004.

Abstract: The dispersion and initial transport of Cryptosporidium oocysts from fecal pats were investigated during artificial rainfall events on intact soil blocks (1,500 by 900 by 300 mm). Rainfall events of 55 mm h super (-1) for 30 min and 25 mm h super (-1) for 180 min were applied to soil plots with artificial fecal pats seeded with approximately 10 oocysts. The soil plots were divided in two, with one side devoid of vegetation and the other left with natural vegetation cover. Each combination of event intensity and duration, vegetation status, and degree of slope (5 degree and 10 degree) was evaluated twice. Generally, a fivefold increase (P ‹ 0.05) in runoff volume was generated on bare soil compared to vegetated soil, and significantly more infiltration, although highly variable, occurred through the vegetated soil blocks (P ‹ 0.05). Runoff volume, event conditions (intensity and duration), vegetation status, degree of slope, and their interactions significantly affected the load of oocysts in the runoff. Surface runoff transported from 10 super (0.2) oocysts from vegetated loam soil (25- mm h super (-1), 180-min event on 10 degree slope) to up to 10 super (4.5) oocysts from unvegetated soil (55-mm h super (-1), 30-min event on 10 degree slope) over a 1-m distance. Surface soil samples downhill of the fecal pat contained significantly higher concentrations of oocysts on devegetated blocks than on vegetated blocks. Based on these results, there is a need to account for surface soil vegetation coverage as well as slope and rainfall runoff in future assessments of Cryptosporidium transport and when managing pathogen loads from stock grazing near streams within drinking water watersheds.

Drinking Water Treatment Processes for Removal of Cryptosporidium and Giardia
Author: Betancourt, WQ; Rose, JB
Source: VETERINARY PARASITOLOGY; VOL 126; NUMBER 1-2; pp. 219-234; 2004

Abstract: Major waterborne cryptosporidiosis and giardiasis outbreaks associated with contaminated drinking water have been linked to evidence of suboptimal treatment. Cryptosporidium parvum oocysts are particularly more resistant than Giardia lamblia cysts to removal and inactivation by conventional water treatment (coagulation, sedimentation, filtration and chlorine disinfection); therefore, extensive research has been focused on the optimization of treatment processes and application of new technologies to reduce concentrations of viable/infectious oocysts to a level that prevents disease. The majority of the data on the performance of treatment processes to remove cysts and oocysts from drinking water have been obtained from pilot-tests, with a few studies performed in full-scale conventional water treatment plants. These studies have demonstrated that protozoan cyst removal throughout all stages of the conventional treatment is largely influenced by the effectiveness of coagulation pretreatment, which along with clarification constitutes the first treatment barrier against protozoan breakthrough. Physical removal of waterborne Crytosporidium oocysts and Giardia cysts is ultimately achieved by properly functioning conventional filters, providing that effective pretreatment of the water is applied. Disinfection by chemical or physical methods is finally required to inactivate/remove the infectious life stages of these organisms. The effectiveness of conventional (chlorination) and alternative (chlorine dioxide, ozonation and ultra violet [UV] irradiation) disinfection procedures for inactivation of Cryptosporidium has been the focus of much research due to the recalcitrant nature of waterborne oocysts to disinfectants. This paper provides technical information on conventional and alternative drinking water treatment technologies for removal and inactivation of the protozoan parasites Cryptosporidium and Giardia.

Evolution of Ontario's Storm water Management Planning and Design Guidance
Author: Bradford, A; Gharabaghi, B
Affiliation: School of Engineering, University of Guelph, Guelph
Source: Water Quality Research Journal of Canada Vol. 39, no. 4, pp. 343-355. 2004.

Abstract: Ontario's Storm water Management, Planning and Design Manual released in March 2003 integrates some of the advancements made in storm water management since the 1994 version of the Manual was published. Perhaps the most significant update is the recognition of in-stream erosion control and water balance objectives in addition to flood and water quality objectives for storm water management. Specific design criteria which would allow these objectives to be achieved are not set out, but procedures that can assist in the development of criteria based on local watershed and receiving water conditions are described. While refinements will undoubtedly be needed, approaches to designing end-of-pipe facilities to prevent undesirable geomorphic changes are included. Approaches to protect groundwater and baseflow characteristics are also included although guidance on addressing potential trade-offs between groundwater quantity and quality is an additional challenge for the future. Little design guidance is available in Ontario on techniques to mitigate impacts on wetlands, however, developments from other jurisdictions may be transferable. The 2003 Manual promotes an integrated, treatment train approach to storm water management that emphasizes prevention first, followed by lot-level and conveyance controls and finally, end-of-pipe controls. Some information on better site design techniques is incorporated but in comparison to other jurisdictions, less emphasis has been placed on low-impact development strategies. Ontario's approach to design for water quality (suspended solids) control has evolved little. To complement the prevention and treatment train philosophy, the removal efficiency approach to sizing end-of-pipe facilities needs to be used in conjunction with effluent criteria and/or minimum requirements for source protection. Significant dvancements in storm water modeling over the last decade are not well reflected in the Manual; the limited discussion of modeling focuses on an event-based approach. Whether event or continuous modeling is utilized, Ontario practitioners will need guidance on adapting input data to account for the anticipated effects of climate change. Development of sound guidance on monitoring increasingly complex, multi-objective storm water management systems and the ecosystems they are designed to protect will be critical to ensure that the knowledge gained from performance evaluations may continue to be utilized to refine the design and management of storm water systems.

Fate and Transport of Pathogens in Lakes and Reservoirs
Author: Brooks, JD; Antenucci, J; Hipsey, M; Burch, MD; Ashbolt, NJ; Ferguson, C
Affiliation: Cooperative Research Centre for Water Quality and Treatment
Source: Environment International Vol. 30, no. 5, pp. 741-759. Jul 2004.

Abstract: Outbreaks of water-borne disease via public water supplies continue to be reported in developed countries even though there is increased awareness of, and treatment for, pathogen contamination. Pathogen episodes in lakes and reservoirs are often associated with rain events, and the riverine inflow is considered to be major source of pathogens. Consequently, the behaviour of these inflows is of particular importance in determining pathogen transport and distribution. Inflows are controlled by their density relative to that of the lake, such that warm inflows will flow over the surface of the lake as a buoyant surface flow and cold, dense inflows will sink beneath the lake water where they will flow along the bathymetry towards the deepest point. The fate of pathogens is determined by loss processes including settling and inactivation by temperature, UV and grazing. The general trend is for the insertion timescale to be shortest, followed by sedimentation losses and temperature inactivity. The fate of Cryptosporidium due to UV light inactivation can occur at opposite ends of the scale, depending on the location of the oocysts in the water column and the extinction coefficient for UV light. For this reason, the extinction coefficient for UV light appears to be a vitally important parameter for determining the risk of Cryptosporidium contamination. For risk assessment of pathogens in supply reservoirs, it is important to understand the role of hydrodynamics in determining the timescale of transport to the off-take relative to the timescale of inactivation. The characteristics of the riverine intrusion must also be considered when designing a sampling program for pathogens. A risk management framework is presented that accounts for pathogen fate and transport for reservoirs.

Modeling Coliforms in Storm Water Plumes
Author: McCorquodale, J A; Georgiou, Ioannis; Carnelos, Susanne; Englande, Andrew J
Source: Journal of Environmental Engineering and Vol. 3, no. 5, pp. 419-431. Jul 2004.

Abstract: The recreational waters near many large cities in the United States and Canada are severely impaired by pathogens that are present in the storm water runoff. In separated sewers the pathogen sources may be cross-flows between the sanitary and storm water systems. This paper presents the methodology that was used in developing a forecasting model for pathogen indicators for recreational sites in the receiving waters of multiple storm water outfalls. The objective of the model is to give a timelier indicator of beach water quality than conventional beach monitoring, which takes about 2 d for laboratory results. The model used for the study was based on the Princeton Ocean Model. The forecasting system consists of nested hydrodynamic models and a bacteria fate-transport submodel. Calibration and validation is based on 6 years of field studies, laboratory analyses, and experiments. The methodology is illustrated by a case study of the impact of storm water flows on the south shore of Lake Pontchartrain, Louisiana, which has been banned for swimming since 1985. The water quality data included: pathogen indicators (fecal coliform, Enterococci, and E. Coli), water chemistry parameters, turbidity, and nutrients.

Safeguarding Our Water
Author: Davis, CR
Affiliation: USFilter Memcor Products in Geneva, IL
Source: Environmental Protection Vol. 15, no. 10, pp. 32-37. Nov-Dec 2004.

Abstract: Beautiful and blue, vast, and sometimes violent, the Great Lakes are truly “Nature's Reservoir.” They contain 20 percent of the earth's fresh surface water, spanning nearly 900 miles from the headwaters of the St. Lawrence River in Kingston, Ontario, in the east to their western fingertip at Duluth, Minn. Within that area is more than 10,000 miles of shore line. The Great Lakes supply more than 40 million Americans and Canadians with water for drinking, industry, recreation, and agriculture. But beneath the surface lurk microbial contaminants that get into the water through urban storm water runoff, combined sewer overflows, natural sources like wildlife feces, and the erosion of millions of tons of topsoil into the lakes each year. These microbes include Cryptosporidium, one-celled parasites only 4 to 6 microns in size that originates in human and animal waste. They are resistant to common disinfection practices and may pass through conventional water treatment filtration processes in sufficient numbers to cause health problems. The problem - never more evident than in 1993 when Cryptosporidium infected over 400,000 people in Milwaukee and caused at least 70 premature deaths - has made it necessary for public drinking water plants to employ the latest in sophisticated water treatment technology to make their water safe. In response, many Great Lakes coastal communities like Kenosha and Manitowoc in Wis., Marquette and Mackinac Island in Mich., and Chatham-Kent in Ontario have installed continuous microfiltration (CMF) membrane filtration systems from USFilter Memcor Products. These systems use hollow fiber microfiltration membranes as the filtering medium. The fiber walls contain tiny pores, which allow water to pass but trap microscopic particles such as cysts and microorganisms.

Urban Wet-weather Flows: Sources of Fecal Contamination Impacting on Recreational Waters and Threatening Drinking-water Sources
Author: Marsalek, J; Rochfort, Q
Affiliation: National Water Research Institute
Source: Journal of Toxicology and Environmental Health, Part A: Current Issues Vol. 67, no. 20-22, pp. 1765-1777. 22 Oct-26 Nov 2004.

Abstract: Discharges of urban stormwater and combined sewer overflows (CSOs) contribute to fecal contamination of urban waters and need to be considered in planning the protection of recreational waters and sources of drinking water. Storm water characterization indicates that Escherichia coli counts in storm water typically range from 10 super(3) to 10 super(4) units per 100 ml. Higher counts (10 super(5) units/100 ml) suggest the presence of cross-connections with sanitary sewers, and such connections should be identified and corrected. Fecal contamination of storm water may be attenuated prior to discharge into surface waters by storm water management measures, which typically remove suspended solids and attached bacteria. Exceptionally, storm water discharges in the vicinity of swimming beaches are disinfected. The levels of indicator bacteria in CSOs can be as high as 10 super (6) E. coli per 100 ml. Consequently, the abatement of fecal contamination of CSOs is now considered in the design of CSO control and treatment, as for example stipulated in the Ontario Procedure F-5-5. CSO abatement options comprise combinations of storage and treatment, in which the CSO treatment generally includes disinfection by ultraviolet (UV) irradiation. Finally, indicator bacteria data from Sarnia (Ontario) were used to demonstrate some fecal contamination impacts of wet-weather flows. In wet weather, the microbiological quality of riverine water worsened as a result of CSO and storm water discharges, and the recreational water guidelines for indicator organisms were exceeded most of the time. Local improvements in water quality were feasible by source controls and diversion of polluted water.

2003

Characterization and Statistical Modeling of Bacterial (Escherichia coli) Outflows from Watersheds that Discharge into Southern Lake Michigan
Authors: Olyphant, GA; Thomas, J; Whitman, RL; Harper, D
Affiliation: Department of Geological Sciences, Indiana University, Bloomington, IN
Source: Coastal Monitoring Through Partnerships, Environmental Monitoring and Assessment, January 2003, 81 (1-3): 289-300

Abstract: Two watersheds in northwestern Indiana were selected for detailed monitoring of bacterially contaminated discharges (Escherichia coli) into Lake Michigan. A large watershed that drains an urbanized area with treatment plants that release raw sewage during storms discharges into Lake Michigan at the outlet of Burns Ditch. A small watershed drains part of the Great Marsh, a wetland complex that has been disrupted by ditching and limited residential development, at the outlet of Derby Ditch. Monitoring at the outlet of Burns Ditch in 1999 and 2000 indicated that E. coli concentrations vary over two orders of magnitude during storms. During one storm, sewage overflows caused concentrations to increase to more than 10,000 cfu/100 mL for several hours. Monitoring at Derby Ditch from 1997 to 2000 also indicated that E. coli concentrations increase during storms with the highest concentrations generally occurring during rising streamflow. Multiple regression analysis indicated that 60% of the variability in measured outflows of E. coli from Derby Ditch (n = 88) could be accounted for by a model that utilizes continuously measured rainfall, stream discharge, soil temperature and depth to water table in the Great Marsh. A similar analysis indicated that 90% of the variability in measured E. coli concentrations at the outlet of Burns Ditch (n = 43) during storms could be accounted for by a combination of continuously measured water-quality variables including nitrate and ammonium. These models, which utilize data that can be collected on a real-time basis, could form part of an Early Warning System for predicting beach closures.

Conceptual Model for Cryptosporidium Transport in Watersheds, A
Author: Park, C-H; Huck, PM
Affiliation: Department of Civil Engineering, University of Waterloo,
Source: Water Quality Research Journal of Canada [Water Qual. Res. J. Can.]. Vol. 38, no. 1, pp. 77-113. 2003.

Abstract: This paper describes a conceptual model to estimate Cryptosporidium parvum oocyst transport from source to water treatment plant intake. The intent of the model is ultimately to be able to predict oocyst concentrations at an intake to an order-of-magnitude level. The transport and fate mechanisms included are: oocyst detachment from waste or soil, generation of runoff, overland transport, reservoir and in-stream transport, and oocyst die-off. The model is formulated in finite difference form, and deals with both non-point this work is the recognition that the settling rates of free and floc- or particle-associated oocysts can be considerably different. This has important implications for their transport. A finite difference scheme was developed for five sections of a hypothetical watershed: a point source, a lake or reservoir (which can be modeled as either a continuous stirred tank reactor or an ideal rectangular setting tank), the section of stream channel from the outlet of the lake or reservoir to the confluence with another stream, a tributary with a non-point source, and the stream section from the confluence to a water treatment plant intake. The stream confluence is handled with a simple mass and flow balance. It would be very expensive to collect the necessary data to test the model. Because an appropriate data set was not available, the model was tested by means of a sensitivity analysis for the hypothetical watershed, using reasonable parameter settings for the base case. The major contribution of the model is in defining the mechanisms involved in oocyst transport within a watershed. It gives important insights into the significance of various factors, provides a basis for data collection, and identifies areas where experimental investigations are required to avoid the need for simplifying assumptions. At its current state of development, the model cannot be used to provide quantitative predictions, but defines a base from which further detailed modeling can be developed to aid in decision-making for pathogen control. Using the framework that this model provides, contributions from other sources of Cryptosporidium oocysts such as domestic animals and combined sewage overflows could also be modeled.

Fate and Transport of Surface Water Pathogens in Watersheds
Author: Ferguson, C; Husman, AMU; Altavilla, N; Deere, D; Ashbolt, N
Affiliation: Sydney Catchment Authority, Sydney, Australia,
Source: Critical Reviews in Environmental Science and Technology. Vol. 33, no. 3, pp. 299-361. Jul 2003.

Abstract: Pathogens present in animal fecal deposits excreted to land undergo a poorly defined process of dispersion, transport or attenuation, and inactivation. The transport of pathogens overland in surface runoff is clearly responsible for event-related increases in the concentrations of in-stream waterborne pathogens in many watersheds. However, there are significant knowledge gaps concerning the precise mechanisms of pathogen transport. This article reviews the fate and transport of pathogens in watersheds supplying drinking water, from their deposition in feces and septic seepages on land to their dispersion in major tributaries. Pathogens considered representative of those associated with waterborne disease included enteric viruses derived from human fecal contamination, bacterial pathogens represented by Escherichia coli O157:H7, and the protozoan pathogens Cryptosporidium and Giardia. References to suitable model and index organisms for these pathogens are described. The key processes determining the fate and transport of pathogens within watersheds are discussed in the context of changing agricultural practices, climate, and scale factors. A generic conceptual model for watershed processes is described in light of the knowledge gaps identified from this review. Future areas for fundamental research were identified and included: (1) inactivation kinetics of pathogens in soil and fecal matrices; (2) characterization of the particle sizes with which pathogens are transported; (3) characterization of pathogen properties and watershed-specific features that affect terrestrial transport and attenuation; and (4) the inactivation and sedimentation of pathogens during their initial introduction to the aquatic environment. Such information is critical to advance the assessment of pathogen total maximum daily loads (TMDL), determining management priorities and appropriate control points, as well as integrating pathogens within the broader watershed hydrologic models.

Modeling the U.S. National Distribution of Waterborne Pathogen Concentrations with Application to Cryptosporidium parvum
Author: Crainiceanu, CM; Stedinger, JR; Ruppert, D; Behr, CT
Affiliation: Department of Statistical Science, Cornell University, Ithaca, New York, USA
Source: Water Resources ResearchVol. 39, no. 9, [np]. Sep 2003.

Abstract: This paper provides a general statistical methodology for modeling environmental pathogen concentrations in natural waters. A hierarchical model of pathogen concentrations captures site and regional random effects as well as random laboratory recovery rates. Recovery rates were modeled by a generalized linear mixed model. Two classes of pathogen concentration models are differentiated according to their ultimate purpose: water quality prediction or health risk analysis. A fully Bayesian analysis using Markov chain Monte Carlo (MCMC) simulation is used for statistical inference. The applicability of this methodology is illustrated by the analysis of a national survey of Cryptosporidium parvum concentrations, in which 93% of the observations were zero counts.

Use of Viral Pathogens and Indicators to Differentiate Between Human and Non-human Fecal Contamination in a Microbial Source Tracking Comparison Study
Author: Noble, RT; Allen, SM; Blackwood, AD; Chu, W; Jiang, SC; Lovelace, GL; Sobsey, MD; Stewart, JR; Wait, DA
Affiliation: UNC-Chapel Hill Institute of Marine Sciences
Source: Journal of Water and Health Vol. 1, no. 4, pp. 195-207. Dec 2003.

Abstract: Assays for the detection and typing of adenoviruses, enteroviruses and F+ specific coliphages were performed on samples created as part of a national microbial source tracking methods comparison study. The samples were created blind to the researchers, and were inoculated with a variety of types of fecal contamination source (human, sewage, dog, seagull and cow) and mixtures of sources. Viral tracer and pathogen assays demonstrated a general ability to discriminate human from non-human fecal contamination. For example, samples inoculated with sewage were correctly identified as containing human fecal contamination because they contained human adenovirus or human enterovirus. In samples containing fecal material from individual humans, human pathogen analysis yielded negative results probably because the stool samples were taken from healthy individuals. False positive rates for the virus-based methods (0-8%) were among the lowest observed during the methods comparison study. It is suggested that virus-based source tracking methods are useful for identification of sewage contamination, and that these methods may also be useful as an indication of the public health risk associated with viral pathogens. Overall, virus-based source tracking methods are an important approach to include in the microbial source tracking `toolbox'.

Windsor Combined Sewer Overflow Treatability Study with Chemical Coagulation
Author: Li, J; Dhanvantari, S; Averill, D
Affiliation: University of Windsor, Civil and Environmental Engineering
Source: Water Quality Research Journal of Canada Vol. 38, no. 2, pp. 317-334. 2003.

Abstract: Long column settling and jar tests were undertaken as part of a treatability study of combined sewage at the Lou Romano Water Reclamation Plant (LRWRP) in Windor, Ontario. Different types of cationic polymers were examined in jar tests, and the appropriate dosage and its relationship with the TSS removal were determined for the polymer coagulation process. Settling column tests were used to develop settling rate distribution curves under both chemically aided and unaided conditions, and to examine the performance of polymer coagulation in improving the settleability of wet-weather sewage during CSO events. The results of the long column settling tests for settling rate distributions show that the characteristics of the wet-weather sewage at the LRWRP during CSO events were similar to those of samples collected at actual overflow sites along the Windsor Riverfront. Settling rate distributions demonstrated that polymer addition to the wet-weather sewage significantly improved the settling characteristics.

2002

Monitoring Dissolved Organic Carbon in Surface and Drinking Waters
Author: Volk, C; Wood, L; Johnson, B; Robinson, J; Zhu, Hai Wei; Kaplan, L
Affiliation: Indiana-American Water Company Inc
Source: Journal of Environmental Monitoring Vol. 4, no. 1, pp. 43-47. Feb 2002.

Abstract: The presence of natural organic matter (NOM) strongly impacts drinking water treatment, water quality, and water behavior during distribution. Dissolved organic carbon (DOC) concentrations were determined daily over a 22 month period in river water before and after conventional drinking water treatment using an on-line total organic carbon (TOC) analyzer. Quantitative and qualitative variations in organic matter were related to precipitation and runoff, seasons and operating conditions. Following a rainfall event, DOC levels could increase by 3.5 fold over baseflow concentrations, while color, UV absorbance values and turbidity increased by a factor of 8, 12 and 300, respectively. Treated water DOC levels were closely related to the source water quality, with an average organic matter removal of 42% after treatment.

Sunlight Inactivation of Human Enteric Viruses and Fecal Bacteria
Authors: Fujioka, RS; Yoneyama, BS
Affiliation: Water Resources Research Center, University of Hawaii
Sources: Water Quality and Environmental Management in Asia, Water Science and Technology, 2002, 46 (11-12): 291-295

Abstract: Three human enteric viruses (poliovirus, echovirus, coxsackievirus) suspended in seawater or buffer were stable for 6 hr in the absence of sunlight but were inactivated at the same rate in the presence of sunlight. Under summer sunlight conditions, at least 3 logs of these viruses were inactivated by one-hit kinetics while under winter sunlight conditions only 1 log of these viruses was inactivated by two-hit kinetics. Under these same conditions, 6 logs of E. coli were inactivated within 1 hr by one-hit kinetics under summer and winter conditions. In comparison, E. faecalis was inactivated by two-hit kinetics and only 2.5 logs of inactivation were observed after 4 hr of exposure to winter sunlight. Since human enteric viruses are considerably more resistant to sunlight inactivation than E. coli and moderately more resistant than E. faecalis, marine recreational water quality standards should be based on concentrations of enterococci and not on coliform bacteria. Since the mechanism and rate of inactivation of coliphage and human enteric viruses are similar, coliphages appear to be the best indicator for the presence of human enteric viruses in recreational waters, especially coastal waters where abundant sunshine is available.

2001

Phenotypic and Genotypic Characterization of Human and Nonhuman Escherichia Coli
Author: Parveen, S; Hodge, NC; Stall, RE; Farrah, SR; Tamplin, ML
Affiliation: Departments of Microbiology and Cell Science
Source: Water Research Vol. 35, no. 2, pp. 379-386. Feb 2001.

Abstract: Estuarine waters receive fecal pollution from a variety of sources, including humans and wildlife. Escherichia coli are one of several fecal coliform bacteria that inhabit the intestines of many warm-blooded animals that sometime contaminate water. Its presence does not specifically implicate human fecal input; therefore it is necessary to differentiate contamination sources to accurately assess health risks. E. coli were isolated from human sources (HS) and nonhuman sources (NHS) in the Apalachicola National Estuarine Research Reserve and analyzed for fatty acid methyl ester (FAME), O-serogroup, and pulsed-field gel electrophoresis (PFGE) profiles. For FAME and PFGE analyses, there was no relationship between profile and isolate source. Human source PFGE profiles were less diverse than NHS isolates, and conversely for FAME. In contrast, O-serogrouping showed less diversity for HS vs. NHS isolates, and the predominant HS O-serogroups differed significantly (P ‹ 0.01) from those of NHS isolates.

2000

Bacteriophages as Indicators of Enteric Viruses and Public Health Risk in Groundwaters
Author: Leclerc, H; Edberg, S; Pierzo, V; Delattre, JM
Affiliation: Laboratoire de Bacteriologie, Faculte de Medicine de Lille
Source: Journal of Applied Microbiology Vol. 88, no. 1, pp. 5-21. Jan 2000.

Abstract: For more than 100 years, there has been debate among microbiologists and public health practitioners concerning the role of drinking water monitoring for either pathogens or indicators. By the 1890s, it was generally accepted that monitoring for specific pathogens was not in the best interest for public health protection because there were too many pathogens, they were present in very small concentrations, and methods for their detection were not practical. Public health officials decided that monitoring would be conducted to detect fecal pollution rather than individual pathogens.

1999-1990

Fate and Transport Model of Cryptosporidium
Author: Walker, FR Jr; Stedinger, JR
Affiliation: School of Civ. and Envir. Engrg., Cornell University
Source: Journal of Environmental Engineering Vol. 125, no. 4, pp. 325-333. Apr 1999

Abstract: The waterborne pathogen Cryptosporidium has been identified in surface drinking water supplies. Suspected sources of this pathogen include sewage and the feces of animals, particularly dairy calves. There are many dairy cattle and significant sewage effluent discharges in the Catskill-Delaware watershed that is part of the New York City water supply system. This water supply serves 8,000,000 customers with 5.8 X 10 super(9) L (1.5 billion gal. of water daily). This paper is concerned with the movement and fate of pathogens from wastewater and dairy sources and the resulting raw water quality for New York City. Manure and Cryptosporidium oocysts are modeled as surface pollutants and assumed to move in response to runoff events in the six watershed-reservoir systems within the Catskill-Delaware watershed. Oocyst degradation in manure and in water is modeled with first-order kinetics. Rudimentary stream routing and reservoir modeling with a first-order decay function complete the fate and transport modeling of oocysts in the watercourse. Reported effluent discharge rates and oocyst concentrations in secondary treated sewage allow estimation of wastewater-derived oocyst contributions. This research highlights the importance of wastewater-derived oocysts, the need for expanded research into oocyst fate in streams and reservoirs, and the concentration of oocysts in sewage effluent.

Guidelines for Indicator Bacteria in Waters: Uncertainties in Applications
Author: El-Shaarawi, AH; Marsalek, J
Affiliation: National Water Research Institute, Burlington, Ontario, Canada L7R 4A6
Source: Environmetrics Vol. 10, no. 4, pp. 521-529. Jul-Aug 1999.

Abstract: Microbiological water quality guidelines have been established in most countries to protect the users from the risk of waterborne diseases. A guideline requires that a minimum number of water samples be collected during a period of time and analysed for an indicator organism. One or more summary statistics are computed and compared to limits specified in the guidelines. When at least one of the limits is exceeded, then certain actions must be taken. Since uncertainty is involved in the implementation of each of these requirements, the use of the guideline is intended to control and not to eliminate the risk from the use of impaired waters. The sources of uncertainties are discussed using two Canadian guidelines for microbiological recreational water quality. However, the methods used are applicable in general to guidelines' specification and use. Criteria are proposed for the selection of an indicator organism and the specification of its limits. The probabilities that quality of recreational water meets the federal guideline are estimated by simulation from the lognormal distribution. These probabilities reveal that imposing a single limit on the maximum eliminates the need for also imposing a limit on the geometric mean. The distributions of the maximum in samples of various sizes are derived by simulation and used to estimate the number of samples needed to detect a predetermined increase in the mean bacterial level. These distributions can be also used to determine the increase in the mean that a sample of a specific size can detect. Finally, the Ontario provincial guideline is compared to its federal counterpart. When the number of samples analysed is less than 15, the Ontario guideline is more conservative, but the reverse is true for larger sample sizes.

Statistical Approach to Pollutant Emissions from Combined Sewer Systems, A
Author: Veldkamp, RG; Wiggers, JBM
Affiliation: Delft University of Technology, Department of Civil Engineering
Source: URBAN STORM DRAINAGE 1996. pp. 95-100. Water Science & Technology Vol. 36, no. 8-9.

Abstract: This research is based on CSO emissions from Dutch sewer systems. During the years 1982 to 1989 research was done on several sewer systems, all of them equipped with a single overflow weir. Pollutant emissions were calculated from the measurements, whereby each storm was considered as a single event. Extreme emissions have a detrimental, sometimes even disastrous effect on water quality. Such extreme emissions are the result of heavy storms, giving it a low frequency of occurrence. From the measurements a statistical model was developed enabling the user to forecast extreme waste emissions with a certain return period in a range of 2 to 10 years. Five pollutants are put in the model: BOD, COD, Kjeldahl nitrogen, total phosphate and suspended solids. The model operates with standardized emission values in kg per ha of impervious area. When the model is used in practice the runoff area to the specific overflow under consideration has to be known.

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