The melting Greenland ice sheet could be a source of toxic mercury, a new study shows.
Runoff water from melting glaciers in Greenland contains as much mercury as highly polluted rivers in heavily populated parts of the world.
These are the findings of a new study that analyzed meltwater flowing from the southeast corner of the ice sheet. The research raises concerns about the amount of mercury entering nearby rivers and fjords, important sources of fish for coastal Greenland communities.
Read the whole story in Scientific American.
Researchers from Florida State University collected meltwater samples on expeditions to the ice sheet in 2012, 2015 and 2018. They also sampled water from several nearby fjords fed by the melting glaciers. Chemical analyses revealed high levels of mercury dissolved in the water.
Mercury concentration in the meltwater rivers were at least an order of magnitude higher than the concentrations found in ordinary rivers across the Arctic. These concentrations became slightly diluted by the time they flowed out into the fjords, but were still higher than expected, the researchers say.
Even after mingling with the salty water, the levels in the fjords remained about an order of magnitude higher than the mercury levels found in most open ocean waters. But the researchers believe the Greenland mercury is coming from natural sources and that the meltwater mercury is probably leaching out of the bedrock beneath the ice.
High mercury concentrations in Greenland’s coastal waters are cause for concern, the researchers say, as waters support a rich marine ecosystem. Fisheries are the linchpin of Greenland’s economy, as well as a primary food source for the island’s Indigenous communities.