When Greg Wetherbee and his colleagues started collecting rainwater in early 2017, microplastics were the last thing on their minds. What they were looking for was evidence of air pollution washing out in the rain. They found that, but they also found plastic - not just a piece or two, but fibers and shards in nine out of ten samples. "These results are actually accidental and opportune,” said Wetherbee, who is a research chemist with the U.S. Geological Survey in Lakewood, Colorado. Wetherbee