Mutagenic Potential of Artificial Athletic Field Crumb Rubber at Increased Temperatures

Abstract

Rubber tires contain several compounds that are known or suspected carcinogens.  Many carcinogens are mutagens, 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 artificial athletic fields, and the surface temperature of these fields can reach levels far above the ambient temperature.  In this study, crumb rubber samples taken directly from four separate artificial athletic field surfaces were used to make leachates using water at different temperatures.  For each of these fields, leachates obtained in water at 70 ºC showed significant mutagenic potential (p ≤ .001) in Salmonella typhimurium fluctuation assays.  Leachates obtained in water at 40 ºC showed no mutagenic potential for any of the fields tested.  For one field, crumb rubber heated in water at temperatures as low as 50 ºC resulted in significant mutagenic potential (p ≤ 0.001).  Water used in an experiment designed to mimic the irrigation of an artificial athletic field also showed mutagenic potential (p ≤ 0.001) in a fluctuation assay.  These results suggest that at the higher temperatures that can exist on artificial athletic field surfaces, the crumb rubber infill on these artificial athletic fields can become the source of a water soluble agent with mutagenic potential in bacteria.