TStudy of Organic Contaminants in Air and Water
in Conjunction with Episodic Events - Great Lakes Experiment

Keri C. Hornbuckle, Sondra Miller (air and water), Gretchen Smith (sediment trap analyses)

Overview:

This study examines the effect of large-scale resuspension on the cycling of persistent organic pollutants (POPs) in southern Lake Michigan. During eight sampling cruises between 1998 and 2000, we have collected over 74 water samples and more than 61 air samples. In addition, Eadie and Lansing have provided sediment from 8 sequencing settling traps and Klump and Waples have provided surficial sediment from the western coastal region. All samples are analyzed for a suite of POPs including 98 PCB congeners, 25 polycyclic aromatic hydrocarbons (PAHs) and 20 chlorinated pesticides.
In June 2000, a paper was submitted to Environmental Science & Technology (attached) the paper reports results from the 1998 field season. In this paper, we report PCB and PAH concentrations in air, water and settling sediments and chemical fluxes for the 1998 resuspension event. In that paper, we examined and affirmed Hypothesis 1, below:

Hypotheses:

Large scale resuspension in southern Lake Michigan causes a reduction in dissolved phase concentration of persistent organic pollutants. We hypothesize that this reduction induces atmospheric deposition of gas-phase POPs. We further hypothesize that this induced load is a significant portion of the total atmospheric load of PCBs and PAHs delivered to Lake Michigan from the atmosphere.
Resuspension of contaminated sediment near the Chicago-Gary region causes an increase in particulate associate POPs in the south-east coastal region. We hypothesize that most of this material does not desorb from the particles. We further hypothesize that these particles fall through the water column and are deposited in the deep basin sediment accumulation zones.

Current Activities:

Air, water and sediment samples are currently being analyzed for the target chemicals. Chemical analyses expected to conclude in spring 2001. Modeling work is on-going through 2002 (funds permitting Ð this project is funded through 2000 by GLNPO/EPA).

Sample Description:
MediaAnalysesStatus: ExtractionStatus: Analytical
Vapor-phase air (hi-vol)POPsCompletedCompleted
Particulate phase air (hi-vol)POPsCompletedIncomplete
Aerosol size distributions (MOUDI)Mass concentration of particles by sizeNAIncomplete
Dissolved phase waterPOPsCompletedIncomplete
Particulate phase waterPOPsIncompleteIncomplete
Sediment trap materialPOPsCompletedIncomplete
Surficial SedimentPOPsIncompleteCompleted