Since the 1940s, road salts have been used to deice roadways during the winter. The most common road salt is NaCl, which, once dissolved, can be easily transported to and stored in nearby soils and waterbodies, causing the degradation of these habitats. Thus, this study examined the retention of road deicing salt ions in soils and their impact on soil physiochemical properties such as pH, organic matter, and water content. Monthly samples were collected near a roadside soil at various distances from the road (0.25-13 m) and depths (0-0.15 m). Prior to road salting, soil Cl- concentrations were low (<15 mg/kg) at every sampling location, but increased rapidly up to 388 mg/kg following deicing applications. Soil Cl- levels were consistently highest near the road, even during non-salting months. However, Cl- added to soils after salting was flushed quickly, particularly near the road, where we observed a 96% concentration decrease only a week after salt applications. We also observed that soil pH near the road increased ~0.66 pH units during the road salting season. Increased soil pH near the road is probably due to salt-derived Na+ replacing H+ on cation exchange sites, leading to H+ leaching. Farther from the road, soil pH was less affected, likely because salt ions were less prevalent. Both soil organic matter and water content were unaffected by road salt applications, with median values remaining constant over time. Understanding the impact of road salt on soils allows us to better assess its harmful impacts on the environment.

Ashleigh Montgomery would like to thank their faculty sponsor Dr. Elizabeth Hasenmueller for their support of this project.