Micro-plastic pollution, which is steadily increasing in the oceans, could seriously threaten populations of oysters and other molluscs, according to a French study whose results were published in the Proceedings of the American Academy of Sciences ( PNAS) Monday 1 February in the United States.
These microbeads less than 5 millimeters in diameter come from the fracturing of pieces of plastic discharged into the oceans under the effect of currents, but also directly from industrial discharges, particularly in the clothing and cosmetics sectors, which use in large quantities.
Reduced molluscan fertilization rate
After two months of exposure to this pollution, these molluscs produced fewer eggs and these were smaller. Similarly, their sperm were much less mobile, says AFP Arnaud Huvet, a biologist at the French Research Institute for Exploitation of the Sea (Ifremer), one of the co-authors of this study.
Thus, “fertilization rates were reduced by more than 41%” compared to oysters that were in a basin in which the content of microbeads were lower, “he says.
For this experiment, “we used the highest levels of plastic microbeads that can be found in nature in highly polluted areas in China,” said the researcher. “Fortunately today we are still far from these concentrations in most of the bays of the planet,” he adds.
But it is clear that this pollution is increasing every year due to the increasing use of plastic and that it is time to make society, industry and the various players aware of trying to reverse this problem. trend, “says the biologist, expert on marine molluscs.
According to him, what has been observed in this study could one day occur in nature, knowing that the figures are alarming in terms of the prediction of pollution by plastic waste by 2050, where there could be more than plastic than fish in the oceans.
Microbeads in cosmetics too
Plastic microbeads are found everywhere, especially in our cosmetics – skin scrubs, shampoo, toothpastes, soaps …. In New York alone, 19 tons of microbeads would be released into the ducts every year, according to research by Sherri Mason, who is studying microbeads at the State University of New York. In the UK, 16 to 86 tonnes of microplastic from facial scrubs would be released into the water each year.
8000 billion microbeads per day
According to a recent study published in the journal Environmental Science & Technology, more than 8000 billion microspheres are inviting in aquatic habitats … every day. Sounds like a lot? The association Surfrider Foundation however explains on its website that “a single tube of these cosmetics, facial or toothpaste, can contain thousands”. In addition to the small balls that you can see and smell, hundreds of others are invisible to the naked eye.
Their small size prevents them from being filtered during their passage in a wastewater treatment plant. Problem: once at sea, these microparticles have a behavior a little special, not only on mollusks so.
They allow microbes to move in the oceans
“They play a role of contaminant transport, like a blotter,” explains to HuffPost François Galgani, a researcher at Ifremer. “These plastic balls serve as a support for species, which can spread from one end of the planet to the other,” he explains. These species can be microbes that, when they arrive in an unknown environment, can unbalance the local fauna and flora, and contaminate beaches and seabed.
Microbeads can also be ingested by organisms living in oceans or lakes, fish, whales, plankton, etc. According to a study published in the Archives of Environmental Contamination and Toxicology, a small salmon from British Columbia could eat two to seven a day. Needless to say, therefore, these microbeads can be found directly on our plates. Moreover, when they degrade, they can release chemicals that are endocrine disruptors. But, tempers François Galgani, “the organisms reject them and the predators do not swallow them”.
An application to avoid them
Until the big companies stop producing microbeads cosmetics and the states forbid them, as is increasingly the case in the United States, an application called beatthemicrobeads (fight the microbeads), created by two NGOs in 2012, allows products to be scanned and detected.
As the Surfrider Foundation explains, as soon as there is written “polyethylene” in the list of components of a product, you can be sure that they are microbeads.