Bioaccumulation refers to the accumulation of chemicals in a living organism. The compound or chemical accumulates at a rate faster than it is being metabolized or excreted by the organism. Chemicals bioaccumulate by binding to the proteins and fats in an organism while others bioaccumulate through the repeated consumption of contaminated organisms.
Pesticides containing chemicals that dissolve easily in fat but not in water tend to bioaccumulate. Pesticides that contain chemicals that can easily be metabolized by organisms do not bioaccumulate. In summary, the nature of the chemical used in pesticides and the capability of organisms to metabolize the said chemicals can dictate whether it will bioaccumulate or not.