Plastic is increasingly ubiquitous, even in remote ocean waters. These microscopic pieces were found in the Arctic Ocean.
ELISA MARTI and ANDRES CÓZAR / University of Cádiz
By Tania RabesandratanaJun. 10, 2021, 18:01
Plastic ends up everywhere – from the summit of Mount Everest to remote corners of Antarctica. Millions of tons of discarded plastic are also washed into the ocean every year. Some of it floats in huge patches of garbage, while other parts fall to the seabed and even appear in deep sea trenches in the hindgut of crustaceans.
According to a UN report on the state of global science published today, research on marine plastic is also growing from just 46 publications in 2011 to 853 in 2019. This year’s edition of the report, published every five years by UNESCO, noted that the growth of marine plastic research outpaced that of the other 55 development-related topics examined (see graph below). “It has really skyrocketed in recent years,” says Erik Van Sebille, oceanographer and climate scientist at Utrecht University, who uses plastic particles as tracers to study ocean dynamics.
Carmen Morales, an ecotoxicologist at the University of Cadiz’s Marine Litter Lab, says plastic is more noticeable than pollutants like metals or organic compounds, and it is attracting more public and policy-makers attention. “It’s a thorn in the side to have all this plastic on the beaches,” adds Bart Koelmans, an aquatic ecologist at Wageningen University. “For many, that’s enough to worry.” Scientists are studying where the plastic comes from, where it goes and how it affects the environment and human health.
But there are gaps in research. Magazines “still get a lot of articles dealing with exactly the same subject: the presence of plastic on beaches, on the ocean floor, or in animals, but not” [many] about sources or solutions, ”says Ángel Borja, marine ecologist at the AZTI research center in Pasaia, Spain.
In a study published today, Morales identified sources by combining data from scattered studies into an inventory of 12 million waste items larger than 2 centimeters. Her team found that take-away food and beverage packaging was the most common: single-use bags, bottles, containers and packaging made up 44% of all waste in all environments.
In the past decade, scientific achievement on plastic litter in the ocean has grown faster than any other research topic relevant to the United Nations Sustainable Development Goals (SDGs).
Plastic waste in the ocean 5.14 Climate-friendly plants 1.87 Higher battery efficiency 1.79 Eco alternatives to plastic 1.65 Water extraction 1.55 Antibiotic resistance 1.47 Hydrogen energy 1.31 New or re-emerging viruses 1.2 Carbon capture and storage 1, 06 HIV 1.02 1.16 Average growth, all areas This graphic shows 10 of 56 topics related to the SDGs that were analyzed in the UNESCO Science Report 2021. A growth rate of 1.16 means a 16% increase in publications between 2012–15 and 2016–19.
C. BICKEL / SCIENCE
Researchers are also trying to understand the environmental impact of plastic pollution. Plastic itself is inert, but often contains toxic additives such as flame retardants, pigments or chemicals to make plastic more flexible and durable. “We are concerned about these additives,” says Morales. Other pollutants, such as polycyclic aromatic hydrocarbons, can enter ecosystems by clinging to floating plastic.
Microplastic particles eroded by larger objects can end up being the same size as plankton, causing marine animals to eat them without receiving any food. Smaller nanoplastic particles can be the most damaging: they can be tiny enough to penetrate tissue, and their shape can make a difference, says Koelmans: Fibrous particles seem to cause more inflammation than spherical ones. However, the overall ecotoxicological effects of plastic are still poorly understood; It is difficult for laboratories to reproduce the cocktail of particles that organisms in the environment are exposed to.
To curb the accumulation of waste, many countries have phased out single-use plastics. By 2018, 127 laws regulating plastic bags had been passed, says UNESCO. But given the low recycling rates, the report says, bans are not enough: biodegradable alternatives are needed.
Research on such materials, derived from vegetable hydrocarbons, is also growing rapidly, albeit more slowly than studies describing the problem. Publications on ecological alternatives to plastics almost tripled from 404 in 2011 to 1111 in 2019, according to the UN report. “I’m happy [to see the figures] because I made the right decision to change my research focus, ”says Carla La Fuente, postdoc chemical engineer at the University of São Paulo, Piracicaba, who is developing green methods to produce biodegradable plastic from cassava starch.
Oceanographer Tiffany Straza, deputy editor of the report at UNESCO, sees parallels between plastic pollution and the problem of nuclear waste. “There was an idea that our science and waste management solutions would catch up while we chased this advanced technology,” she says. But nuclear waste disposal practices lagged as nuclear power emerged. “I’m not convinced we have fully learned this lesson,” she says. “Are we going to do the same with plastics?”