Climate change has left an Arctic town unable to drink its tap water as thawing permafrost exposes bedrock, allowing heavy metals to leach into the local drinking water source.
Manganese 25 Times Above Limit, Tap Water Declared Unsafe
Residents of Longyearbyen, the largest settlement in Norway's Svalbard archipelago, have been told not to drink tap water because of heavy metal contamination caused by thawing permafrost, Britain's Guardian newspaper reported on the 19th.
The town's main drinking water source is Isdammen, a 2.5-kilometer-long closed lake. As rising temperatures thaw the permafrost and expose new bedrock, metals are leaching into the lake. Longyearbyen, located 1,287 kilometers from the North Pole, is warming five to seven times faster than the global average, with autumn temperatures rising by as much as 4 degrees Celsius per decade.
"The thawing of permafrost, combined with the geological characteristics of shale bedrock containing pyrite, is causing contamination of the water supply," said Marjolein Vere, an associate professor at the University Centre in Svalbard.
"The acidic material produced this way dissolves heavy metals in the rock and carries them into waterways," she said. "In Longyearbyen, manganese is the problem, but other contaminants can also leach from the rock."
The local government issued a warning to the town's 2,600 residents last September after confirming that manganese concentrations in the water supply were 25 times higher than the Norwegian public health authority's limit of 50 micrograms per liter.
Mayor Terje Aunevik said at the time that manganese levels had "increased explosively." Prolonged exposure to manganese can cause problems in the nervous systems of children and infants.
Nickel Also Exceeds Limits as Authorities Weigh Water Supply Options
Authorities set up a central tank of water purified at a local brewery as a temporary measure for residents. Manganese levels later declined, but concentrations of sulfate and nickel exceeded recommended limits early this year. The ban on drinking tap water remains in place.
Aunevik has raised the possibility of rebuilding the water supply system entirely. Options under review include installing filtration equipment at Isdammen, setting up a desalination plant for emergency use, or making desalination the primary source of supply. The obstacles are the enormous cost and the extreme climate, where water temperatures fall below freezing.
"In Norway, where we have always taken for granted that you can drink the tap water, it is not easy to accept that we now have to carry water ourselves," Aunevik said. "Other small communities should also think ahead about what to do in case this happens to their drinking water."
Vere said the conditions of pyrite- and heavy-metal-rich bedrock combined with thawing permafrost exist in other Arctic regions as well. "What is happening here may be an early picture of how climate change could affect fresh water in places such as northern Canada or Alaska," she said.