Trend Analysis of Road Salt Impacts on Groundwater Salinity at a Long-term Monitoring Site

A large amount of deicing salt is applied each year on highways in North America to keep the road passable and safe. There has been concern about the potential for the salt to migrate downward to contaminate groundwater quality. The University of Regina and Saskatchewan Highways and Transportation have conducted a long term salt impact monitoring study on a section of highway near Regina, Saskatchewan. This paper will present the groundwater portion of this long-term monitoring study on the environmental impacts of road salt. Salt concentration data from three monitoring wells beside the highway section are presented for initial analysis, and the data from one well is analysed to detect trends using non-parametric statistical approaches. The statistical tests show that chloride concentration has a significant upward trend with an increase of 0.2 mg/L per year at the significance level of 0.05 over more than ten years monitoring period. However, no significant upward trend is found for sodium concentration data at the same significance level.