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. RHMA contains crumb rubber, a recycled rubber product derived from scrap tires. The use of crumb rubber in recycled applications has diverted nearly 20 percent of the total waste tires from other disposal methods over the past several years. The introduction of crumb rubber into paving surfaces not only diverts tires from landfills, but also reduces road noise and increases the longevity of the pavement.
