“Based on the latest U.S. guidelines for PFOA in drinking water, rainwater everywhere would be judged unsafe to drink. Although in the industrial world we don’t often drink rainwater, many people around the world expect it to be safe to drink and it supplies many of our drinking water sources,” Cousins continue.
The Stockholm University team have conducted laboratory and field work on the atmospheric presence and transport of PFAS for the past decade. They have noted that the levels of some harmful PFAS in the atmosphere are not declining notably despite their phase out by the major manufacturer, 3M, already two decades ago. PFAS are known to be highly persistent, but their continued presence in the atmosphere is also due to their properties and natural processes that continually cycle PFAS back to the atmosphere from the surface environment. One important natural cycling process for PFAS is the transport from seawater to marine air by sea spray aerosols, which is another active research area for the Stockholm University team.
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“So now, due to the global spread of PFAS, environmental media everywhere will exceed environmental quality guidelines designed to protect human health and we can do very little to reduce the PFAS contamination. In other words, it makes sense to define a planetary boundary specifically for PFAS and, as we conclude in the paper, this boundary has now been exceeded,” said Scheringer.