2021 U.S. Scrap TIre Workgroup (USSTWG)

Cal Recycle research – contribution of zinc from RHMA • “This report describes research conducted to determine whether rubberized hot mix asphalt (RHMA), used in a growing number of road pavement projects, is a significant source of zinc to stormwater runoff from roadways” • “The increasing use of RHMA in California roadways raises the question about the contributions of these surfaces to contaminants in stormwater runoff, with the main contaminant of concern being zinc.” • “For the scenarios examined, leaching from the rubber in the binder of RHMA is a comparably minor source of zinc in roadway stormwater runoff, contributing less than 0.3 percent of the total zinc load. In the Eureka area, the load from zinc in precipitation greatly exceeded that of the RHMA leachate and the tire wear particles on a relatively lightly traveled highway.” • See: https://www2.calrecycle.ca.gov/Publications/Detai ls/1700 10