Bioaccumulation is the accumulation of substances like pesticides or chemicals in an organism through uptake from ingestion, inhalation, or dermal contact. It involves three stages - uptake where the chemical enters the organism, storage where it is deposited in tissues, and elimination where it is removed from the body. Chemicals that do not dissolve readily in fat have a greater potential to bioaccumulate in organisms. Examples of hazardous chemicals that can bioaccumulate include mercury, DDT, and lead. Factors like exposure duration, chemical concentration, organism lifespan, and anatomy affect bioaccumulation levels. Effects of bioaccumulation include birth defects, reproductive failure, and if it occurs in important food chain organisms, disruption of the entire food chain