![]() ![]() ![]() When larger pieces of plastic waste are disposed of in the environment they get weathered and degrade. Sewage and wastewater treatment plants are primarily designed to treat waste, and do not have the capability to filter out most microplastics before being released into the environment.Every time synthetic textiles are washed, 700,000 tiny pieces of plastic fabrics break off, and up to 40% of them enter rivers, lakes and oceans.64% of fabric is made from plastics, including polyester, nylon, acrylic and polyamide."Different additives seem to absorb different frequencies of sunlight, which influences how fast the plastic breaks down," Reddy says.How Microplastics are Generated Washing Textiles The study also found that additives to polystyrene, which can determine its color, flexibility, and other physical features, play a major role in 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 CO 2. 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 CO 2 and filtered water. The scientists then collected CO 2 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 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. Considering how this transformation happens will be an important part of estimating how much plastic is actually out in the environment, he adds. Once the plastic undergoes this transformation, its original form disappears from the environment, and it becomes entirely new byproducts that cannot be seen by the naked eye. The idea that sunlight degrades plastics is nothing new, Ward says: "Just look at plastic playground toys, park benches, or lawn chairs, which can rapidly become sun-bleached." 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. Polystyrene has been routinely detected in the world's oceans since the 1970s. 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 justification for writing policy that bans it. "Right now, policy makers generally assume that polystyrene lasts forever in the environment," says Collin Ward, a marine chemist at WHOI and lead author of the study. ![]()
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