2.2.19—Microplastics

Microplastics are small plastic particles that can absorb or adsorb persistent pollutants such as PCBs from surrounding water. When organisms ingest contaminated particles, the plastic and associated chemicals can enter trophic pathways.

Plankton or filter feeders may ingest particles, predators eat many contaminated prey, and persistent chemicals that are absorbed and poorly excreted can bioaccumulate and biomagnify. Transfer depends on particle size, polymer, pollutant binding, gut residence and whether the chemical desorbs into tissue.

Contaminated microplastics ingested by zooplankton can be transferred to small fish and then larger predators. Finding particles in predators demonstrates transfer, but showing toxic impact requires tissue concentration, dose and biological-effect evidence rather than particle presence alone.

Microplastics do not automatically magnify every attached chemical. Distinguish physical particle transfer from chemical uptake, compare exposure routes such as food and water, and avoid claiming causation from detection alone.

A high predator concentration does not prove predators created the pollutant; it reflects accumulation and food-web transfer.