Cumulative Risks to Eastern Oysters, Crassostrea virginica in the James River, VA

• Main Author: Lele, Vrushali
• Format: Others
• Published: VCU Scholars Compass 2011
• Subjects: Cumulative Risk Assessment; Eastern Oysters; Probabilistic Risk Assessment; Oxygen Uptake; Environmental Sciences; Physical Sciences and Mathematics
• Online Access: http://scholarscompass.vcu.edu/etd/2472; http://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=3471&context=etd

In an effort to apply Cumulative Risk Assessment (CRA) as developed by the U.S. EPA, the present study investigates the cumulative risks to Eastern oysters due to multiple stressors such as salinity, temperature and oxygen and carbon dioxide. I also compared the effectiveness of the Hazard Quotient Method (HQ) in CRA. Ambient conditions in the James River, VA were obtained from the Virginia DEQ database and respiratory responses were estimated using values from the literature. The multiple environmental stresses are evaluated using a probabilistic analysis that combines the environmental conditions. It was concluded that salinity was the most influential stressor in the model. Other risks were identified contributing to the vulnerability of the oysters. Crystal Ball simulations yielded that the oxygen uptake of oysters reduced by more than 29%. The HQ method was found to be inappropriate in analyzing cumulative risks for CRA. Oyster populations are dramatically declining in the James River and the Chesapeake Bay. Hence, effective oyster restoration activities are underway to rebuild oyster populations in the James River and throughout the Bay area.