Scientists have discovered a new type of plastic pollution – “plasticrusts” – a layer of plastic encrusted onto ocean rocks.
Researchers from the Marine and Environmental Sciences Centre first observed the plastic patches on the Portuguese island of Madeira in 2016.
“We discovered the plasticrusts for the first time in 2016. At that moment, we were already quite surprised and concerned about the phenomenon,” marine ecologist Ignacio Gestoso García told CNN.
“We revisited the same study site some more times during 2017 and 2018,” he said. “Earlier this year we noticed that these plasticrusts were more abundant and have therefore initiated a more rigorous monitoring of the phenomenon.”
After sampling rocks along the coastline, researchers found that by 2019 the crusts now covered 9.46% of the rocky surface.
Tests revealed that the crusts were made of polyethylene – one of the most commonly used types of plastic, used in plastic packaging, construction materials and medical devices.
In a paper, which was published in the Science of The Total Environment journal, researchers concluded the plastic pollution could have come from a number of sources, including fishing and tourism.
“We are convinced this is not a case exclusive of Madeira, and most likely this new phenomenon will be reported in other global regions. However, we would like to remake that for now, plasticrusts are confined to a particular site of the island and future surveys need to be conducted to evaluate and quantify the relevance of plasticrusts,” García added.
Scientists warned that the potential impact of these new plasticrusts was still relatively unknown, but had the potential to affect the island’s animals.
Researchers thought that the plasticrusts were “very unlikely” to have an impact on human health. “Future studies should focus on evaluating whether marine invertebrates cohabiting in the same habitat where plasticrusts are present, can assimilate plastics – and if that’s the case, whether these plastics can have implications for the health of these animals,” Garcia said.
“Plastic debris is one of the most extensive pollution problems our planet is facing today and a particular concern for marine environment conservation,” the study said.
Richard Thompson, a professor of marine biology who was not involved with the study, said “Whatever their background – the plastic industry, policymakers or members of the public – people are agreed: There is too much plastic in the oceans and we need to do something about it.
“At the moment, most of the cost of the waste plastic is not borne by the plastics producers, it is born by local authorities,” Thompson said. “Or the cost is borne by the environment.”
“We need to make sure that that cost of the plastic waste is internalized and is borne by the people that are making the plastic items. Until the cost is brought to bear at the origins and the design stage of the plastic, we will continue to see this problem because there is no incentive at the moment on the industry to design things with responsibility in mind,” Thompson added. “Plastics have great potential to bring societal benefit, but we need to accept the true cost rather than just the cost of production.”