Some scientists studying the Great Lakes say they’ve figured out what is causing mercury levels in the fish to increase or remain steady, despite a reduction in area pollution.
Three years ago, some scientists were puzzled by an increase in mercury levels in areas of the Great Lakes despite a prior steady decline in mercury levels since the 1970s. The levels still weren’t surpassing U.S. Environmental Protection Agency thresholds, according to a 2017 article by the Detroit Free Press, but scientists were stumped by how this was happening.