Geostatistical and Hydrochemical Trends in The Upper Passaic River Basin : Impact of Road Deicing Application

Sodium chloride deicing salts have been used to remove snow and ice from roadways in the Northern United States since the early 1900s. Road deicing reduces accident rates, road delays, and improve road accessibility. While it is known that the use of road deicers is beneficial, road salts have also been shown to affect surface water and groundwater quality. This study conducted major ion concentration analyses on groundwater samples collected by the United States Geological Survey (USGS) for the Upper Passaic River Basin (UPRB). Results show that the contribution of chloride to total dissolved solids increased significantly by 2010. Trend plots show strong correlation of increases in sodium and chloride with time that are not observed with other major ions such as calcium and magnesium. Decadal bivariate plots of sodium against chloride show strong increases in correlation from 1960 to 2010 and an overall strong correlation while those of calcium against chloride and calcium against sodium display poor correlation. Plots of piper diagrams show that the ionic composition of groundwater samples has changed through time, starting as a single Ca(HCO3)2 species and shifting towards a NaCl dominated species. In general, groundwater in the UPRB is fresh with total dissolved solids less than 500 mg/L. Against the natural evolutionary trend, chloride is found to dominate other chemical species in this freshwater system. The findings of this study show evidence that NaCl road salt application can be linked with changes in groundwater composition for the UPRB

Road Deicing Salts on Groundwater in the Upper Passaic River Basin, New Jersey

It is known that the use of road deicers is beneficial, but road salts have also been shown to affect surface water and groundwater quality. This study conducted major ion concentration analyses on groundwater samples collected by the United States Geological Survey (USGS) for the Upper Passaic River Basin (UPRB). Results show that the contribution of chloride to total dissolved solids increased significantly by 2010. Trend plots show strong correlation of increases in sodium and chloride with time that are not observed with other major ions such as calcium and magnesium. Decadal bivariate plots of sodium versus chloride show strong increases in correlation from 1960 to 2010 and an overall strong correlation, while those of calcium versus chloride and calcium versus sodium display poor correlation. Plots of Piper diagrams show that the groundwater facies have changed through time, starting as a single Ca(HCO3)2 species and shifting gradually towards a NaCl dominated species. In general, groundwater in the UPRB is fresh with total dissolved solids less than 500 mg/L. Against the natural evolutionary trend, chloride is found to dominate other chemical species in this freshwater system. The findings of this study show evidence that NaCl road deicing salt application can be linked with changes in groundwater composition in the UPRB

Road deicing and Groundwater Chemistry in Water Management Areas 03 & 04, New Jersey

Multivariate, time series, and regression analyses of major ion concentrations were performed on a decadal basis for field data of the 1960s, 1980s, 1990s, 2000s, and 2010s to determine if there is a statistically significant increase in calcium, chloride, and sodium relative to other major groundwater ions in New Jersey’s Water Management Areas 03 (Middle Passiac River Basin, MPRB) and 04 (Lower Passaic River Basin, LPRB). For the MPRB, sodium and chloride levels were found to be increasing at different rates. There was no significant correlation between chloride and sodium, or between chloride and total dissolved solids. The groundwater facies showed little to no change through time. Sodium and chloride showed only slight to moderate increases from the 1960s to 2010s in the groundwater. Groundwater in the MPRB is relatively free of road deicing salts, probably due to the combination of low deicing application and the occurrence of the low-permeability bedrock of basalts, gneisses, and granites. Comparatively, sodium, chloride, and calcium concentrations increased at substantially greater rates in the LPRB. Plots of sodium versus chloride, and calcium versus chloride showed strong correlations, suggesting an observable relationship between the ions individually produced by the applied deicing salts (NaCl and CaCl2). Additionally, calcium showed no correlation with sodium, suggesting the lack of an intermolecular relationship between the two deicing agents. These observations indicate that road deicing application in the LPRB has contaminated the underlying groundwater. The high urbanization, high road density, and the permeable bedrock are considered to be responsible for the contamination