Basic Course: Supplemental Topics

Bioaccumulation: Introduction

Another aspect of exposure to waterborne chemicals concerns exposure through the consumption of contaminated fish and shellfish. For this reason, national 304(a) water quality criteria for the protection of human health address the process of chemical bioaccumulation in aquatic organisms.

When deriving national 304(a) criteria to protect human health, EPA accounts for potential bioaccumulation of chemicals in fish and shellfish through the use of national Bioaccumulation Factors (BAFs). The goal of EPA’s national BAFs is to represent the long-term average bioaccumulation potential of a chemical in edible tissues of aquatic organisms that are commonly consumed by humans throughout the United States. (Recall that Section 304(a)(1) of the CWA requires that EPA periodically review and publish criteria for water quality that accurately reflect the latest scientific knowledge on the kind and extent of all identifiable effects on human health and welfare.)

Key Point. A national BAF is a ratio (in L/kg) that relates the concentration of a chemical in water to its expected concentration in commonly consumed aquatic organisms in a specified trophic level.

See, for example, the equation below for deriving noncarcinogenic effects, which includes the BAF term.

Learn More. Information on the importance of the trophic level in regard to BAFs. Proceed to the Learn More Topic. »

Disclaimer:
For informational purposes only–Not official statements of EPA policy.