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Non-stick frying pans may cause persistent pollution

作者:南泶源    发布时间:2019-03-06 10:14:00    

By Alison Motluk Canadian scientists have found that materials used to coat pans, such as Teflon, degrade into trifluoroacetic acid (TFA) when heated. This is an extremely persistent compound that stays in the environment. “All of the ‘dirty dozen’ are relatively non-persistent compared to this,” says Scott Mabury of the University of Toronto, referring to the United Nations’ top 12 blacklisted chemicals. Surgical needles and engine additives are also made with fluorinated polymers such as Teflon and Kel-F. Until now, scientists have blamed TFA on hydrochlorofluorocarbons (HCFCs), the gases that replaced the ozone-destroying chlorofluorocarbons. But rainwater in big cities like Toronto contains far higher levels of TFA than can be explained by HCFCs alone. Mabury and his colleagues wondered if fluorinated polymers might be a crucial contributor. They tested a range of fluoropolymers that are all heated in the course of normal use. The researchers collected and analysed the gases released when the materials were heated and found that one of these breakdown products could combine with gases in the troposphere to form TFA. Environmental models confirmed that fluorinated polymers are the likely culprit. The predicted amounts of TFA produced by pans and other products corresponded almost exactly with levels found in the Toronto rain. “We believe it’s a significant portion of the missing TFA in the environment,” says Mabury. TFA is only mildly toxic to plants and is not known to be harmful to humans. Journal reference: Nature (vol 412,

 

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