Maryland Department of Natural Resources

MGS presented research at the 2018 Maryland Water Monitoring Council Annual Conference, December 7, 2018

Temporal variations in chloride concentrations in groundwater in the Piedmont Physiographic Province of Maryland

Tiffany VanDerwerker


The use of road deicing salts has been shown to have significant impacts on groundwater, which may threaten drinking water sources. In the Maryland Piedmont Physiographic Province, unconfined aquifers are the primary water source for people on private water wells, and these aquifers are susceptible to surface-based contamination. High-chloride water from deicing salt can damage plumbing fixtures, appliances, and pipes. Removal of chloride from domestic well-water systems requires the installation of relatively expensive reverse-osmosis systems. Additionally, the impacts of these salts on the mobilization of trace elements, heavy metals, and adsorbed contaminants have not been adequately evaluated. In the late 1980s and 1990s, the Maryland Geological Survey (MGS) sampled many wells in the Maryland Piedmont region, testing the water samples for chloride and other major ions and constituents. Because of increased growth, there is an increased risk of rising chloride concentrations in this region. These data provide a valuable baseline against which future water-quality samples can be compared to monitor changes in groundwater chemistry. MGS will resample approximately 50 wells over the next two years and analyze these samples for similar constituents as previous samples. Targeted groups of wells will be evaluated for temporal changes in chloride concentrations.