Assessment of Heavy Metals and Road Salt in Road Runoff and Strategies for Mitigation
Runoff from highways contain an array of pollutants that may impair local freshwater resources. Among the most ubiquitous classes of freshwater pollutants stemming from roads in northern climates are heavy metals and de-icing salts. Part one of this research tests the heavy metal removal performance of tubular compost biofilters. A treatment train of nine compost biofilters was found to be effective at attenuating heavy metals over multiple years of exposure to real-world conditions. The environmental management of road salt must focus on reduced usage. This necessitates an understanding of current salt usage as it relates to storm conditions, of which there may be a wide variety of approaches between winter maintenance agencies. Part two of this research characterizes the relationship between key meteorological variables and salt application quantities, ultimately yielding an improved salt application guidance protocol tailored specifically to a single winter maintenance agency and class of roadway.