How can biomagnification increase chemical concentrations at higher trophic levels?

Biomagnification is an ecosystem-level process where the concentration of certain contaminants increases progressively as they move up the food web. This occurs because organisms at higher trophic levels consume large quantities of contaminated prey, leading to a cumulative increase in the chemical burden within their tissues.12

For a substance to biomagnify, it typically must be resistant to degradation and fat-soluble, allowing it to persist in the environment and accumulate in the fatty tissues of living organisms. When a predator eats prey that has already bioaccumulated these chemicals, the predator ingests the total load of the contaminant present in the prey's body. Because the predator consumes many such prey items over its lifetime, the concentration of the chemical in the predator's tissues becomes significantly higher than the concentration found in the prey or the surrounding environment.213

In the context of plastic pollution, plastics can concentrate pollutants from seawater and deliver them to organisms upon ingestion, potentially leading to both bioaccumulation and subsequent biomagnification in higher-level predators.4