Dissolved metals in roadway stormwater runoff can exceed water quality standards and state departments of transportation (state DOTs) in many parts of the country are being required to reduce the concentrations of these pollutants. NCHRP Report 767: Measuring and Removing Dissolved Metals from Stormwater in Highly Urbanized Areas
evaluated a variety of media for removing dissolved metals from roadway stormwater runoff. The research concluded that granulated ferric oxide (GFO) performed well under controlled conditions, but that stormwater best management practices (BMPs) that use GFO should be field tested. Additional research is needed to evaluate the potential benefits and life-cycle costs of using GFO in state DOTs’ stormwater management programs.