Bioaccumulation is the gradual build up of chemicals in an organism over time through uptake from the environment and storage in tissues. Uptake occurs through activities like eating, drinking, breathing and skin contact, while storage deposits chemicals in organs or tissues. Certain chemicals that bind tightly, like mercury, can accumulate even if water soluble. Biomagnification further concentrates chemicals as they move up the food chain, potentially harming top predators. While bioaccumulation aids nutrient acquisition, it can also be detrimental depending on the chemical and organism.