Bioaccumulation

General term describing a process by which chemicals are taken up by an organism either directly from exposure to a contaminated medium or by consumption of food containing the chemical. 1. The process whereby certain toxic substances collect in living tissues, thus posing substantial hazard to human health or the environment. Bioaccumulation is the process by which chemicals concentrate in an organism. For example, DDT concentrates in fish and birds that eat fish. This concentration effect is expressed as the ratio of the concentration of the chemical in an organism (like a fish) to its concentration in the surrounding medium (usually water). Bioaccumulation refers to the uptake of chemicals both from water (bioconcentration) and from ingested food and sediment. The accumulation within living organisms of toxic substances occuring in the environment.

http://extoxnet.orst.edu/faqs/glossary.htm http://www.epa.gov/oswer/riskassessment/glossary.htm#b