Researchers collected and analysed water from three rivers and two fjords near the ice sheet.
The water was tested for the presence of mercury with the researchers astonished with the concentrations they found.
Typically, scientists would expect to see between one and 10 ng L-1 of dissolved mercury in rivers.
These levels are comparable to a salt grain-sized blob of the toxic metal in an Olympic swimming pool.
The glacial meltwaters collected in Greenland, meanwhile, had mercury levels in excess of 150 ng L-1.
Even more worryingly, mercury levels carried by so-called glacial flour – a sediment that gives glacial lakes a milky colour – were in excess of 2,000 ng L-1.