T10 PM Advances in Bioaccumulation Assessment
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 341-342

(HEN-1117-745179) U.S. EPA's methodology for developing national bioaccumulation factors.

Henry, T¹, Cook, P², Burkhard, L², Endicott, D³, Sappington, K⁴, Winchester, E⁵, ¹ U.S. EPA, Office of Water, Office of Science & Technology, Washington, DC, USA² U.S. EPA, Office of Research & Development, National Health and Envrionmental Effects Research Laboratory, Duluth, MN, USA³ Great Lakes Environmental Center, Traverse City, MI, USA⁴ U.S. EPA, Office of Research & Development, National Center for Environmental Assessment, Washington, DC, USA⁵ U.S. EPA, Office of Research & Development, Office of Science Policy, Washington, DC, USA

ABSTRACT- In 2000, the U.S. Environmental Protection Agency (EPA)'s Office of Water published the Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health. This methodology incorporates a number of scientific advancements made over the past two decades, one of which is in the assessment of chemical exposure to humans through the food chain pathway. EPA's methodology uses trophic level-specific bioaccumulation factors (BAFs) and fish ingestion rates to account for exposure to chemicals from the consumption of freshwater and estuarine fish and shellfish. Although national-scale estimates, EPA's national BAFs are intended to account for major chemical and biological attributes that can affect bioaccumulation and can vary between regions and ecosystems. Therefore, within the EPA framework for deriving national BAFs, different procedures are used for deriving BAFs for different types of chemicals. Each procedure is specifically suited for the class and properties of chemicals to which the procedure applies. The BAF derivation methods used within EPA's framework range from empirically-based measurements of organism and media concentrations to mechanistically-based predictions based on chemical properties combined with food web modeling. To provide transparency, clarity and consistency, EPA has published the national BAF framework, including detailed discussion of the scientific basis, advantages, and limitations of each BAF derivation method. EPA's use of BAFs, which account for chemical accumulation in fish and shellfish from all potential exposure routes, ultimately results in more accuracy and certainty in setting national 304(a) ambient water quality criteria.

Key words: Bioaccumulation, Ambient Water Quality Criteria, Food Chain Exposure, Fish and Shellfish