There is growing concern about effects marine microplastics may have on people, including toxic chemicals leaching from plastic litter and the fact that “microscopic particles are making their way into the food chain and affecting human health. But are they harmful?”^[1]

It appears that the marine food web is full of plastic. It has been found in the stomachs of deep sea fish in the Northwest Atlantic,^[2]in fish in the English Channel,^[3]in endangered sea turtles,^[4],[5]in giant Bluefin tuna off the coast of Lebanon^[6]and in the stomach of a whale that died off the coast of Norway in 2017.^[7]Concerns include that when ingested, microplastics can affect the feeding behaviours of marine animals and cause weight-loss. Another fear is that when smaller fish are eaten by predators like tuna and swordfish, the plastic moves up the food chain. Chemical pollutants can also bind to microplastics and may increase accumulations of toxins in larger predatory fish – and so particles and toxins can end up on our plates. Such toxins could pass through cell membranes, potentially increasing exposure to harmful chemicals.

However, assessing the risks to human health from marine plastic is complex and there is still much we do not know about its potential to affect human health.^[8]In addition, “the uptake of plastic-associated chemicals in humans due to inadvertent ingestion of microplastics in seafood appears likely to be no more significant than other human exposure pathways of these chemicals.”^[9]