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Road salting linked to persistent chloride concentrations in bedrock


Road salt application for deicing has increased in the United States since the 1940s and many studies have shown its environmental impact in surface water and shallow groundwater. However, despite the dependence of many rural communities on bedrock wells as a primary water source, little has been studied on the impacts of road salting on water quality in bedrock.

In an article recently published in the Journal of Environmental Quality, researchers investigated the water quality in two crystalline bedrock wells at the University of Connecticut in Storrs over a thirteen-year period, with particular emphasis on impacts of increased salt application (4x-15x) with a change in deicing practices at the university after 2009.

Chloride was found to be highly persistent in the bedrock, with concentrations consistently increasing from 2003 to 2016 despite annual variations in salt application, suggesting some degree of accumulation. A dramatic increase in chloride occurred in the wellbores in response to the change in deicing practices, with an immediate response in fractures having a direct connection to the overburden.

Given the critical importance of bedrock aquifers for water supplies, this study argues that consideration be given to subsurface contamination when developing deicing management strategies, particularly in regions where bedrock is shallow.

Read the full article in JEQ. Free preview April 28 - May 5