Presentation Abstract

High polychlorinated biphenyl (PCB) concentrations in Lake Washington fish prompted the Washington Department of Health to issue a fish consumption advisory in 2004. To address PCB bioaccumulation in Lake Washington fish, King County was awarded a Puget Sound Action Agenda: Technical Investigations and Implementation Assistance Grant by the U.S. Environmental Protection Agency. An investigation of PCB loadings to Lake Washington was complemented by the development of 1) a contaminant fate model and 2) a bioaccumulation model to predict tissue PCB concentrations in Lake Washington fish. This presentation will describe the bioaccumulation model - a Gobas-type food web model adapted to Lake Washington. The model predicts whole-tissue contaminant concentrations in food web components (e.g., phytoplankton, zooplankton, benthic invertebrates, and fish) by calculating chemical uptake from ingestion and respiration as well as elimination from respiration, excretion, metabolism and growth dilution. The required model inputs include the food web structure of Lake Washington for the taxa of interest as well as physical and chemical parameters (e.g., biota lipid content, concentration of suspended solids, organism wet weight). The model was run using both water and sediment PCB concentrations derived from empirical data and those predicted by the fate model. To test the model performance, model predictions were compared to observed PCB concentrations in Lake Washington biota. Overall, the model performed best using water and sediment concentrations predicted by the fate model; almost all predicted PCB concentrations fell within a factor of two of average observed concentrations in Lake Washington biota. This model was used to estimate the magnitude of reductions in water and sediment PCB concentrations necessary to bring PCBs in Lake Washington fish to safe levels.

Session Title

Session S-06B: Lake Washington's PCB Fish Advisory: How Do We Make Progress?

Conference Track

Toxics

Conference Name

Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)

Document Type

Event

Start Date

1-5-2014 1:30 PM

End Date

1-5-2014 3:00 PM

Location

Room 608-609

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

Text

Language

English

Format

application/pdf

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May 1st, 1:30 PM May 1st, 3:00 PM

The Lake Washington PCB/PBDE Study: Modeling Bioaccumulation of PCBs in Lake Washington Fish

Room 608-609

High polychlorinated biphenyl (PCB) concentrations in Lake Washington fish prompted the Washington Department of Health to issue a fish consumption advisory in 2004. To address PCB bioaccumulation in Lake Washington fish, King County was awarded a Puget Sound Action Agenda: Technical Investigations and Implementation Assistance Grant by the U.S. Environmental Protection Agency. An investigation of PCB loadings to Lake Washington was complemented by the development of 1) a contaminant fate model and 2) a bioaccumulation model to predict tissue PCB concentrations in Lake Washington fish. This presentation will describe the bioaccumulation model - a Gobas-type food web model adapted to Lake Washington. The model predicts whole-tissue contaminant concentrations in food web components (e.g., phytoplankton, zooplankton, benthic invertebrates, and fish) by calculating chemical uptake from ingestion and respiration as well as elimination from respiration, excretion, metabolism and growth dilution. The required model inputs include the food web structure of Lake Washington for the taxa of interest as well as physical and chemical parameters (e.g., biota lipid content, concentration of suspended solids, organism wet weight). The model was run using both water and sediment PCB concentrations derived from empirical data and those predicted by the fate model. To test the model performance, model predictions were compared to observed PCB concentrations in Lake Washington biota. Overall, the model performed best using water and sediment concentrations predicted by the fate model; almost all predicted PCB concentrations fell within a factor of two of average observed concentrations in Lake Washington biota. This model was used to estimate the magnitude of reductions in water and sediment PCB concentrations necessary to bring PCBs in Lake Washington fish to safe levels.