Scientists discovered that the levels of toxic methylmercury in the Great Salt Lake in Utah have decreased by almost 90 percent. This seems to be good news, yet the mysterious vanishing of the toxic compound is being investigated.
The findings of the study were published in Environmental Science and Technology. William Johnson, a geologist from the University of Utah, said that there could be a link between these high concentrations of methylmercury down in the deep brine layer and the elevated concentrations in waterfowl in the wetlands near the lake. He further said that if there is a direct link between the mercury in the ducks and the environment at the bottom of the lake, people could think they will see a lessening of mercury in biota, which is the animal and plant life. On the other hand, they did not view it as that.
The wildlife officials discovered that the Great Salt Lake has high levels of toxic methylmercury around 2010. With this, they warned hunters to avoid eating ducks that might poison them. Then, in 2015, about 90 percent of the mercury vanished, according to Science Alert.
A Union Pacific railway separates the small north arm and the large south arm of the Great Salt Lake. The north arm is much saltier than the south arm. There are two culverts in the railroad line that permitted the north arm water to flow in the south arm due to its higher density.
Johnson said that the difference in density between the shallow and deep waters inhibited mixing. This kept fresh oxygen from permeating into the layers of the deep water. The decomposing organic matter on the lake floor extracted all the oxygen from the briny layer.
As a result, the microorganism was forced to find something else to breathe. In the absence of oxygen, some bacteria become nitrate to stimulate the chemical processes of life. On the other hand, when the nitrate has vanished, they become manganese, iron and sulfate.
The presence of the sulfate-breathing bacteria, which is a sulfide and smells like a rotten egg, are oozing from the lake. These bacteria become elemental mercury into toxic methylmercury, according to The University of Utah News.