ROAD SALT IN BEDROCK AQUIFERS - IS THERE A PROBLEM

The use of various chloride compounds for winter road maintenance has been steadily increasing for decades. Previous research is summarized, and it is seen that the environmental fate of chloride and the long term impact on bedrock aquifers is poorly understood. Chloride concentrations in three well in Maine are compared with water level data from nearby USGS monitoring wells. The results show a consistent negative correlation between water levels and chloride concentrations. These observations lead to the hypothesis that chloride sequestering (accumulation of chloride in low flow or dead end fractures) is an environmental phenomenon that is actively occurring. Potability of bedrock aquifers near roads may be at risk for future generations. Potential response of groundwater professionals is explored.