Final answer:
Bioaccumulation of plastics and their chemical components is a concern because it leads to an increasing concentration of nonbiodegradable substances in higher trophic levels of an ecosystem. For example, polychlorinated biphenyls (PCBs) biomagnify in aquatic ecosystems, resulting in high levels in top predatory fish and the birds that consume them.
Step-by-step explanation:
Bioaccumulation is a concern because it leads to an increasing concentration of nonbiodegradable substances, such as plastics and their chemical components, as they pass from lower to higher trophic levels in an ecosystem. This means that organisms higher up in the food chain, like fish-eating birds, can accumulate high levels of these substances. For example, polychlorinated biphenyls (PCBs), which were used in coolant liquids until their ban in 1979, have been found to biomagnify in aquatic ecosystems, resulting in high levels in top predatory fish and the birds that consume them.