Plastic waste drifts in huge carpets on the oceans, accumulates as microplastics in the environment, food and living organisms and could also have as yet unknown toxic effects if it breaks down into its components through weathering. Researchers are now warning that current plastic emissions could trigger harmful effects worldwide that cannot be reversed. You are therefore calling for drastic political measures. According to the researchers, recycling efforts alone are not enough.
Plastic is now everywhere on earth: from deserts and mountain peaks to deep oceans and arctic snow. In 2016, estimates of the global release of plastic into lakes, rivers and oceans ranged from 9 to 23 million tons per year, with a similar amount occurring annually on land. Without far-reaching political action, researchers expect these numbers to almost double by 2025. Although public and political awareness of the problem of plastic pollution has increased, plastic litter continues to increase.
Irreversible damage
“Plastic is deeply rooted in our society and gets into the environment everywhere, even in countries with good waste treatment infrastructure,” says Matthew MacLeod of Stockholm University in Sweden. Together with his colleagues, he has written a review on known and conceivable dangers of plastic pollution. In it, the researchers write: “Our analysis confirms that plastic pollution can pose a global threat and that measures to drastically reduce plastic emissions are the rational political answer.”
Plastic accumulates in the environment in various forms. While garbage from populated areas can still be collected relatively easily, remote natural areas that are difficult to access are particularly at risk. “In remote environments, plastic waste cannot be removed by cleaning up, and the weathering of large plastic parts inevitably leads to the formation of a large number of micro- and nanoplastic particles and to the leaching of chemicals,” explains co-author Annika Jahnke from RWTH Aachen University. “So plastic in the environment is a constantly moving target of increasing complexity and mobility. Where it accumulates and what effects it can cause is difficult or perhaps even impossible to predict. “
Biological and geophysical effects
The authors identify numerous areas in which plastics of various types are known or may cause problems. On the biological level, on the one hand, large plastic parts are dangerous: “A recent analysis listed 914 species of marine animals that are affected by being caught or swallowed, including 226 species of sea birds, 86 species of marine mammals, all species of sea turtles and 430 species of fish,” the researchers report . In addition to these often immediately fatal consequences, it has also been proven that microplastics accumulate in the body of living beings – with consequences that have not yet been fully foreseeable.
Geochemical and geophysical effects are also conceivable. The researchers believe it is possible that plastic pollution affects global carbon cycles. For example, microplastics in the ocean could affect the cyanobacteria and microalgae that live there, which then bind less carbon dioxide from the atmosphere. So instead of flowing into marine food webs, this carbon would remain in the atmosphere and exacerbate climate change. At the same time, carbon bound in plastic and not usable by biological organisms would sink to the sea floor and accumulate in the sediment. The slow decomposition of these plastic deposits could also produce substances that have a toxic effect.
Drastic policy action needed
“At the moment we are polluting the environment with increasing amounts of poorly reversible plastic pollution. So far, we don’t see widespread evidence of serious consequences, but if plastic weathering causes a really bad effect, we probably won’t be able to reverse it, ”warns MacLeod. “The cost of ignoring the build-up of persistent plastic pollution in the environment could be enormous. The most sensible thing we can do is act as soon as possible to reduce the amount of plastic entering the environment. “
The current technologies for removing plastic from the environment and recycling it are far from sufficient, according to the researchers. “As consumers, we believe that if we properly separate our plastic waste, everything can be magically recycled,” says co-author Mine Tekman from the Helmholtz Center for Polar and Marine Research in Bremerhaven. “Technologically, however, plastic recycling has many restrictions, and countries with good infrastructure export their plastic waste to countries with poorer facilities.”
In order to effectively reduce the release of plastic, drastic measures are required. “This includes, for example, limiting the production of new plastic to add value to recycled plastic, and banning the export of plastic waste unless it goes to a better recycling country,” says Tekman.
Source: Matthew MacLeod (Stockholm University, Sweden) et al., Science, doi: 10.1126 / science.abg5433