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n. The accumulation of a substance, such as a toxic chemical, in various tissues of a living organism: the bioaccumulation of mercury in fish.

n. The process by which substances accumulate in the tissues of living organisms; used especially of toxic substances that accumulate via a food chain

"Also, there is no evidence that any of the oil or dispersant components are being taken up by smaller organisms, and then built up in concentrations in larger organisms - a process called bioaccumulation, Guidry said."

accumulation