Mystery of the missing mercury at the great Salt Lake

Typography

Around 2010, the deep waters of Utah’s Great Salt Lake contained high levels of toxic methylmercury. Mercury measurements in waterfowl surrounding the lake led to a rare human consumption advisory for ducks.

But by 2015, 90 percent of the deep mercury was gone.

The disappearance of the mercury was not due to aggressive environmental policies or a wide-ranging cleanup effort. Instead, it’s part of a story involving a large-scale unplanned chemistry experiment, a sometimes-stinky lake, and ducks – in which the mercury did not disappear. The story is told in a paper published in Environmental Science & Technology.

Around 2010, the deep waters of Utah’s Great Salt Lake contained high levels of toxic methylmercury. Mercury measurements in waterfowl surrounding the lake led to a rare human consumption advisory for ducks.

But by 2015, 90 percent of the deep mercury was gone.

The disappearance of the mercury was not due to aggressive environmental policies or a wide-ranging cleanup effort. Instead, it’s part of a story involving a large-scale unplanned chemistry experiment, a sometimes-stinky lake, and ducks – in which the mercury did not disappear. The story is told in a paper published in Environmental Science & Technology.

A Union Pacific railway line crosses the lake, dividing it into a smaller north arm and a larger south arm, with the line drawn right at the base of the bunny-ear-like northern extensions of the lake. Because the north arm has no major river inflow, it’s much saltier than the south arm. Two culverts in the railroad line allowed briny north arm water to flow into the south arm and, because of its higher density, sink to the bottom of the south arm.

Continue reading at University of Utah

Image: The Union Pacific causeway separates the blue south arm (left) and the purple north arm (right) of the Great Salt Lake.

Image Credits: University of Utah