우레탄 트랙 납 오염 현황과 위해성평가에 관한 제언

In this study, the contamination of urethane track samples with lead (Pb) was investigated, and the previous results of human health risk assessment for Pb in urethane track samples were critically reviewed. Two extraction methods (i.e., acid digestion and ultrasonication) were applied. An acid digested urethane track sample from an elementary school showed the highest Pb concentration of 1,526 mg/kg, which exceeded the guideline of 90 mg/kg. The same sample was ultrasonicated, and the concentration was 1.51 mg/kg. This level is lower than a mean concentration of Pb in soils, suggesting that the exposure of Pb by urethane tracks could not be serious. Since Pb is classified into a non-carcinogen, a Hazard Quotient (HQ) can be calculated based on an Average Daily Dose (ADD) and a Reference Dose (RfD). It was found that the total exposure of Pb could be overestimated by the estimation of hand-to-mouth exposure. Furthermore, a RfD of Pb was not established by the US EPA, and the WHO withdrew a previously established Provisional Tolerable Weekly Intake (PTWI). Therefore, the results of health risk assessment using previous RfD values are quite uncertain to be used for the management of urethane tracks exceeding the concentration guideline. In conclusion, a more systematic approach should be developed to deal with this issue.