A study by researchers at the South Dakota School of Mines & Technology on
the concentration of mercury in the sediments of seven South Dakota lakes found
that the pollutant generally enters the water bodies through runoff and can
increase during times of flooding and lake expansion.
The paper, titled “Historical
sediment mercury deposition for select South Dakota, USA, lakes: implications
for watershed transport and flooding,” was published this year in the Journal
of Soils and Sediments.
Emissions from coal fired power
plants are the main source of mercury pollution around the world. Mercury is distributed
through the atmosphere until it settles on the land. Global deposition of mercury
began with the start of the industrial revolution and peaked in the United
States in the 1970s. The concentrations have gone down with emission reductions
and pollution control in more recent decades. Historic mining and industrial operations
are less common sources of mercury pollution.
The objective of the study was to
determine the main source of mercury and to understand the history of mercury
deposition on a diverse range of lakes in the state. The study included Wall
Lake, West 81 Lake, Lynn Lake, Island Lake, Lake Hurley and Lake Sinai in the
eastern part of the state, and Lake Isabel ...