Mutagenic potential of artifcial athletic field crumb rubber at increased temperatures

Abstract

Rubber tires contain several compounds that are known or suspected carcinogens. Many carcinogens are mutagens (Grifths et al. 2000), and fluctuation assays based on the Ames test can be used as an initial screen for mutagenic potential. Granulated crumb rubber from recycled tires is commonly used in the creation of artifcial athletic felds, and the surface temperature of these felds can reach levels far above the ambient temperature. In this study, crumb rubber samples taken directly from four separate artifcial athletic feld surfaces were used to make leachates using water at different temperatures. For each of these felds, leachates obtained in water at 70°C showed signifcant mutagenic potential (p ≤.001) in Salmonella typhimurium fluctuation assays. Leachates obtained in water at 40°C showed no mutagenic potential for any of the felds tested. For one feld, crumb rubber heated in water at temperatures as low as 50°C resulted in signifcant mutagenic potential (p ≤ 0.001). Water used in an experiment designed to mimic the irrigation of an artifcial athletic feld also showed mutagenic potential (p ≤ 0.001) in a fluctuation assay. These results suggest that at the higher temperatures such as those on artifcial athletic feld surfaces, the crumb rubber infll on these artifcial athletic felds can become the source of a water soluble agent with mutagenic potential in bacteria.