Environmental and health study SBR rubber granulates
Erik van Swinderen* and Nicole Salzmann, ISA Sport
In a Dutch study the composition and the leaching behaviour of infill rubber made from granulated car tyres was investigated. The granulates that were tested were sampled at the manufacturers of ground up car tyres and at artificial turf pitches from one to three years old. Rubber granulate was also artificially aged in the laboratory, using climate simulation, for use in the environmental study. The experimental health study focused on the absorption of polycyclic aromatic hydrocarbons (PAHs) through skin contact with rubber granulate. In addition to migration test models, the urine of sports enthusiasts was tested for the presence of PAH conversion products, after they had been in close contact with rubber granulate. From the composition study it is possible to deduce that in particular Zinc (Zn), volatile organic components (VOC) and PAHs are potentially hazardous substances. The leaching study found a striking increase in Zn leaching in relation to rubber granulate ageing. The levels of leached PAHs were low and judged to be irrelevant. To assess the environmental risks, the results of the composition and leaching tests were assessed against the Dutch Building Materials Decree, which is a legislation that formally only applies to stone-like materials. This test concluded that the level of PAHs in all the samples that were measured complied with the limiting values. The level of the VOCs that were tested also complied, with the exception of xylene in one of the field samples. Formally, the level of Zn leaching did not comply with the Building Materials Decree because after between 3 and 20 years it exceeded the immission limiting values. However, the other heavy metals and anions did comply. In addition to Zn leaching, there is also an environmental risk involved in the spreading of rubber granulate to the soil surrounding the artificial turf pitch. Careless housekeeping that mixes rubber granulate with the surrounding soil can result in a considerable increase in the levels of Zn and PAH in the soil. A literature study used to determine the health risks of exposure through swallowing or inhaling concluded the risk was negligible. The migration study used in the laboratory to test for the possible absorption of organic components via the skin concluded that the calculated exposure is lower than the recommended limiting values for negligible risk. In addition, the urine of sports enthusiasts who had had close contact with the rubber granulate, was tested before, during and after training for the presence of 1-hydroxy pyrene, a conversion product of pyrene (PAH). The absorption of PAH while playing sports on an artificial turf pitch could not be determined unambiguously. If there was absorption via the skin, it was limited and within the range of PAH exposure from other sources in the environment and from food. The final conclusion was that there were no significant health risks to sports enthusiasts through the use of infill rubber from granulated car tyres on artificial turf pitches.