Residents of Longyearbyen in Norway’s Arctic archipelago of Svalbard have been told not to drink tap water after contamination that scientists have linked to thawing permafrost, The Guardian reported.
The town’s main drinking water source is Isdammen, a dammed lake. Researchers believe rising temperatures are exposing rock that releases metals into the water.
“The combination of the thawing permafrost and the shale bedrock, which contains a mineral called pyrite, or fool’s gold, is causing contamination of its water supply,” Marjolaine Verret, an associate professor in Arctic geology at the University Centre in Svalbard, told The Guardian.
Pyrite reacts with water and oxygen to produce acid, she explained.
“The acid produced can now leach heavy metals from these rocks into the waterways. The issue we’ve been having here in Longyearbyen is manganese, but other contaminants can be leached out from the rocks.”
Authorities first alerted the town’s 2,600 residents in September last year after manganese concentrations reached 25 times the Norwegian Institute of Public Health’s recommended level of 50 micrograms per litre, according to the report.
Mayor Terje Aunevik said the water had long contained sediment, but manganese levels had “gone ballistic”.
Residents were given access to a tank of free purified water at the local supermarket, with the town’s brewery helping filter the supply.
Manganese levels have since fallen. However, sulphate and nickel concentrations exceeded recommended drinking water limits earlier this year, keeping the restriction in place.
An expensive fix and a warning for the Arctic
Aunevik told The Guardian that a “completely new water mains supply” might be needed. Options include filtering water from Isdammen and installing a desalination plant, with one system serving as a backup.
Either option would be “extremely expensive”, he said, with Svalbard’s freezing conditions adding technical difficulties.
“In Norway, where we have always taken for granted that we can drink the water from the tap, it is challenging to start thinking that we need to carry our water like we do now. Other small communities should be precautious and start thinking of what to do if it happens to their sources.”
Longyearbyen is warming at between five and seven times the global average rate, The Guardian reported. Scientists warn that the combination of thawing ground and metal-bearing rock could threaten water supplies elsewhere in the Arctic.
“These ingredients [bedrock rich in pyrite and heavy metals] and thawing permafrost are present in other parts of the Arctic so this could be a first example of how climate change can impact freshwater, for example in northern Canada and Alaska,” Verret said.