Plastics and chemicals
Plastic pollution directly affects many species, including birds, marine mammals, fish and filter feeders through entanglement and ingestion. More than 180 types of animals have been recorded as ingesting plastic debris, which may have serious direct consequences such as decreased feeding stimuli, gastrointestinal blockage and decreased secretion of gastric enzymes and decreased levels of steroid hormones, leading to reproduction and other problems.
Plastic pollution may also assist invasive and destructive fauna such as barnacles, bryozoans, polychaetes, dinoflagellates, algae, molluscs and even ants to migrate and invade new territories, as they can adhere to the plastic debris and use it as a transport mechanism.
Many plastics also contain toxic chemicals in the form of additives, stabilisers, curing agents or colorants. Chemicals such as bisphenol A (BPA), plasticizers (phthalates), and ﬂame retardant chemicals (polybrominated diphenyl ethers or PBDEs) are known endocrine disruptors. Plastics also act as carriers for other chemicals, which then will be slowed or entirely prevented from degradation due to sorption. Both toxic additives and contaminants can and will bioaccumulate along the entire food chain.
Finally plastic sorbs and even concentrates organic contaminants found in the environment at various levels of the food chain. The extent of this depends on the type of plastic as well as ultraviolet weathering and other environmental factors.