Science News, July 4, 1987 v132 p6(1) Using tires to track pollution. Richard Monastersky. Full Text: COPYRIGHT Science Service Inc. 1987 Using tires to track pollution Like detectives, scientists must rely on telltale clues when tracking down the major sources that pollute water systems near cities. In one of the latest investigations, researchers suggest that microscopic bits of a tire tread will lead them to one of these sources of contamination: the toxic chemicals that run off roads into bays and estuaries. These results come from an analysis of sediments from the bottom of San Francisco Bay. Scientists from the Lawrence Livermore National Laboratory in Livermore, Calif., report in the June 25 NATURE that they found high concentrations of an unknown substance, which they subsequently identified as rubber compounds from automobile tires. They propose that these compounds, called benzthiazoles, could serve as a tracr for certain toxic chemicals called polynuclear aromatic hydrocarbons (PAHs). PAHs are present in petroleum and are produced by incomplete combustion of anything from wood to gasoline. They are a major threat to the wildlife of estuaries, say Livermore scientists. As part of car exhaust, PAHs settle on the road and wash into water systems via runoff during rain. Other sources range from industrial discharge to oil spills, and scientists need to gauge how much each source contributes to the total amount of PAH contamination. Article A5076100