![]() ![]() The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Mellon Foundation, the Stanley Watson Chair in Oceanography, and a Graduate Research Fellowship from the National Science Foundation. The research was funded by the Frank and Lisina Hoch Endowed Fund, the Andrew W. Walsh of WHOI and the Massachusetts Institute of Technology. Reddy, 10 October 2019, Environmental Science and Technology Letters.Īlso collaborating on the paper were Cassia J. Reference: “Sunlight Converts Polystyrene to Carbon Dioxide and Dissolved Organic Carbon” by Collin P. “Different additives seem to absorb different frequencies of sunlight, which influences how fast the plastic breaks down,” Reddy says.įor more on this study, read Polystyrene, a Common Plastic, Degrades Much Faster Than Expected. The study also found that additives to polystyrene, which can determine its color, flexibility, and other physical features, play a major role in the breakdown. But we need more research to understand what happens to the other products that dissolve into water,” says Ward. “We used multiple methods to do this, and they all pointed to the same outcome: sunlight can transform the polystyrene into CO2. With a variety of chemical tools, including a room-sized accelerator mass spectrometer, Ward and colleagues traced the origins of carbon atoms found both in the CO2 and filtered water. The scientists then collected CO2 and compounds that dissolved into the water. The group submerged each of them in sealed glass containers of water and shined light on them from a solar simulator, a lamp that replicates the frequencies of sunlight. In the lab, the researchers tested whether sunlight could transform polystyrene by exposing five different samples of commercially available polystyrene. ![]() Absorbing that energy can break apart the carbon bonds. “Although the ring-based backbone of polystyrene makes it a difficult target for microbes, it’s the perfect shape and size to catch certain frequencies of sunlight,” Ward adds. The WHOI study shows that sunlight doesn’t just cause the plastics to physically break down, however, it also causes them to degrade chemically into dissolved organic carbon and trace amounts of carbon dioxide, at levels far too low to impact climate change. The chemical structure of polystyrene is complex and bulky with a ring-based backbone that will stymie microbes or just make the plastic not worth the effort. Plastic is just another form of organic carbon and presumably microbes would “eat it” - but he cautions that microbes are smart and selective, too. That’s not entirely surprising, says Chris Reddy, a marine chemist at WHOI and co-author on the paper. Past studies have largely focused on the role microbes play in degrading them, rather than considering other factors like sunlight. Previous estimates of how quickly polystyrene breaks down were based on a different set of assumptions, Ward says. ![]() The chance for injury to the environment over decades is still available.” We’re not saying that plastic pollution isn’t bad, just that the persistence of polystyrene in the environment may be shorter and likely more complicated than we previously understood. One of our motivations for this study was to understand if polystyrene actually does last forever. “That’s part of the justification for writing a policy that bans it. “Right now, policymakers generally assume that polystyrene lasts forever in the environment,” says Collin Ward, a marine chemist at WHOI and lead author of the study. The study was published on October 10, 2019, in the journal Environmental Science and Technology Letters. Credit: Jayne Doucette, Woods Hole Oceanographic InstitutionĪ study published by researchers at Woods Hole Oceanographic Institution (WHOI) shows that polystyrene, one of the world’s most ubiquitous plastics, may degrade in decades or centuries when exposed to sunlight, rather than thousands of years as previously thought. Polystyrene pollution at the tide’s edge. ![]()
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