Bioaccumulation Test

Assessing bioaccumulation plays a critical role in understanding the risks posed by chemicals to the environment. Persistent chemicals can accumulate in aquatic organisms through the direct uptake from water (bioconcentration) or through the consumption of contaminated food (biomagnification). Test species include a variety of cold and warm water fish species such as trout, bluegill and carp, as well as invertebrates such as oysters, aquatic worms, and earthworms.

Bioaccumulation in Fish

Aqueous bioconcentration studies are conducted to assess a chemical’s bioconcentration factor (BCF) in fish. Fish are exposed to the chemical dissolved in water and the BCF is calculated as the ratio of the concentration in the fish to the dissolved concentration in water at steady-state, or by the ratio of the uptake and depuration rate constants. For poorly soluble substances where stable and measurable concentrations are difficult to obtain, a bioaccumulation test can be performed using spiked feed, resulting in a dietary biomagnification factor or BMF. Kinetic BCF (BCFk) can be estimated from a BMF study, where fish and fish food are collected and analyzed during the test.

OECD 305: Bioaccumulation in Fish: Aqueous and Dietary Exposure
OCSPP 850.1730. Fish BCF.

Bioaccumulation in Sediment-dwelling Benthic Oligochaetes

Designed to assess bioaccumulation of sediment-associated chemicals in endobenthic oligochaetes. Test organisms are exposed to chemicals via multiple uptake routes, including direct ingestion of sediment, surface contact and ingestion of pore water. Oligochaetes, sediment and overlying water samples are collected analyzed at specified intervals. The primary endpoints are a bioaccumulation factor (BAF) and a biota-sediment accumulation factor (BSAF).

OECD 315: Bioaccumulation in Sediment-dwelling Benthic Oligochaetes

Bioaccumulation in Terrestrial Oligochaetes

Designed to assess bioaccumulation of chemicals in terrestrial oligochaetes, test organisms are exposed to soil dosed with the test chemicals and oligochaetes and soil are collected and analyzed at intervals. The primary endpoints are a BAF and a biota-soil accumulation factor (BSAF).