When marine organisms ingest plastic, it works its way up the food chain. This is the case with microplastics, which are polluting the seas, fish, molluscs and crustaceans — and ending up on our plates.
The presence of plastic in the oceans is a growing phenomenon that is alarming researchers: it is estimated that as many as eight million tonnes of plastic enter the sea every year, in the form of microbeads or fragments resulting from the degradation of other waste, such as packaging, containers and other items.
The report La plastica nel piatto, dal pesce ai frutti di mare (a summary of the report Plastics in seafood, Greenpeace research laboratories, 2016), produced by Greenpeace, brings together the most recent and in-depth studies on both microplastics — which form when plastic breaks up into small fragments at sea — and microbeads, plastic particles created for use in cosmetics and other personal hygiene products such as toothpastes and shaving foams. Too small to be filtered out by water treatment plants, microbeads slip from our sinks directly into waterways and make their way into the oceans. Fish mistake them for food and ingest them, and in this way they work their way up the food chain to humans.
Once they reach the sea, microplastics can both absorb and release toxic substances. The report explains that there are at least 170 marine organisms that ingest such fragments. A recent study carried out on 121 specimens of fish from the central Mediterranean, including commercial species such as swordfish, bluefin tuna and albacore tuna, found plastic fragments in 18.2 per cent of the samples analysed. Studies conducted on 26 species of fish from the Portuguese Atlantic coast revealed the presence of microplastics in 19.8 per cent of the tests carried out: the highest quantities were detected in the Atlantic chub mackerel, a species similar to the mackerel. A study on Dublin Bay prawns found plastic fragments in the stomachs of 83 per cent of the specimens collected along British coasts.
The problem also affects molluscs in Brazil, China and Europe, where microplastics have been found in mussels and oysters from farms or collected directly in the wild.
Studies carried out on mussels collected along the Brazilian coast found microplastics in 75 per cent of the samples analysed.
Sufficient research is not yet available to define the possible risks to human health, but a number of problems linked to the ingestion of microplastics through seafood products have nonetheless been identified, ranging from the direct interaction between these particles and the body's cells to uncontrolled exposure to the additives and contaminants associated with microplastics. The available data, according to Greenpeace, confirm the urgent need to apply the precautionary principle, by banning the production of microbeads and establishing strict rules to reduce plastic use in general.
"A growing body of scientific evidence shows that microplastics can have serious consequences for marine organisms and end up on our plates. A ban on the production of microbeads is, for the Government and Parliament, the simplest way to demonstrate concern about the effects of marine pollution and the related risks to human health, even if it is only a first step towards addressing the extremely serious problem of plastic in our oceans," says Giorgia Monti, oceans campaign coordinator at Greenpeace Italy.
On the initiative of the association Marevivo , a legislative proposal has already been tabled. This is a precautionary measure, currently under consideration in numerous countries, that is necessary to halt the consumption of these materials as soon as possible.