Shellfish Bioaccumulation and Contaminant Level Study, Atlantic Wood Industries

U.S. Environmental Protection Agency, under contract to CDM

Overview:

• Conducted time-critical sampling campaigns of contaminant levels in oysters and blue crabs in the lower Chesapeake Bay
• Designed and executed a dual-phase study of the bioaccumulation potential and contaminant levels of metals, SVOCs, and dioxin/furans in edible and specialized tissues (e.g., hepatopancreas) of resident species
• Supported human health and ecological risk assessments
• Commended by CDM and EPA for quick response and work quality

Description:

AVATAR designed and conducted a dual phase study of the chemical contamination of 2 commercially and recreationally important species – the Eastern oyster, Crassostrea virginica, and the blue crab, Callinectes sapidus in the Elizabeth and York River estuaries in the lower Chesapeake Bay.

A total of 600 oysters were used in a 2 month caged oyster study to evaluate uptake and bioaccumulation of a number of priority pollutants in sub-adult oysters placed at 3 locations in the Elizabeth River and 1 reference location in the York River. Metrics evaluated included change in shell length, total weight, meat weight, and oyster condition. In addition, water and sediment quality were monitored throughout the study. In addition to caged oysters, natural oyster beds at several locations were harvested to evaluate contaminant levels.

The blue crab survey consisted of the collection and processing of approximately 300 blue crabs from 2 locations in the Elizabeth River and 1 location in Kings Creek – a tributary to the York River. All crabs were measured for length, weight, sex. The hepatopancreas and the edible meat was dissected and removed from each crab, weighed, homogenized and processed for subsequent chemical analyses. At each location, 8 replicates of hepato-pancreas tissue and edible tissue were submitted for analysis of metals, SVOCs, and dioxin/furan.

Spatial data for the sample locations and associated equipment were collected for development of a GIS based data system integrating the oyster and crab results with the locations of potential sources of contamination. Following the receipt of the chemical data, a report and statistical analyses were prepared and submitted to EPA for use in updating the human health and ecological risk assessments for the Atlantic Wood Industries site.