Plastics discarded in the oceans decompose to the point where they end up in what we eat and drink. Faced with this phenomenon, scientists are still struggling to assess the consequences of these microplastics and nanomaterials on our health.
Would you like another serving of microplastic? Through human activities, 8 million tonnes of plastic make their way every year into the oceans. Of the nearly 400 million tonnes of plastic manufactured per year, 81% become waste within months. Non-biodegradable, these materials fragment, decompose and become part of the fauna and flora. They are thus found in coastal and remote areas, but also in the majority of marine organisms studied. These particles of less than 5 millimeters ultimately end up in our food. Scientists have recently begun studying the effects on marine creatures and humans.
Not all products from the sea are equal in terms of transmission risk. The risk of transmission to humans is higher for seafood, because "we consume the digestive system that contains the plastic particles," explains Guillaume Duflos, researcher at a food safety laboratory in Boulogne, France. As for fish, there is less risk, because only the fillet is consumed. What about the quantities ingested by the consumer? "The latest data from an American study show that we could ingest from 39,000 to 59,000 particles per year," notes the scientist. A researcher in the Netherlands, Albert Koelmans of Wageningen University, suggested it could range from dozens to 100,000 specks each day per person, a report in Nature outlined.
What are the effects on human health?
In various parts of the world, researchers are trying to measure human exposure. One issue that further complicates this task is that of nanoplastics, which are less than 1 micrometre and difficult to count as scientists can't even see them.
Regarding the effects on health, researchers are divided on the issue and cautious about drawing conclusions at this early stage, with most hopeful that effects are limited. CNRS researcher Mélanie Auffan of CEREGE explains that "studies done on the impact of nanosilver on small shrimps, gammares, in fresh and estuarine waters do not show any toxic effect and the dispersion seems low." However, there is a growing demand for actions to reduce plastic pollution.
While significantly reducing plastic waste would require drastic action and changes from industry, it is possible to take action on an individual level by reducing one's own consumption of single-use products. To track one's daily input and output, the Zero Waste Objective app can help the transition towards (almost) zero waste.