Increased urinary 8-hydroxy-2′-deoxyguanosine levels in workers exposed to di-(2-ethylhexyl) phthalate in a waste plastic recycling site in China

Abstract

Di-(2-ethylhexyl) phthalate (DEHP) is a common plasticizer used in industrial and diverse consumer products. Animal studies indicate DEHP caused developmental, reproductive, and hepatic toxicities. However, human studies of the potential effects of DEHP are limited. The exposed site with a history of over 20years of waste plastic recycling was located in Hunan Province, China. The reference site without known DEHP pollution source was about 50km far away from the exposed site. In this study, 181 workers working in plastic waste recycling and 160 gender-age matched farmers were recruited. DEHP concentrations in water and cultivated soil samples, serum thyroid-stimulating hormone, malondialdehyde (MDA), superoxide dismutase (SOD), urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), and micronuclei frequency in human capillary blood lymphocytes were analyzed. Mean levels of DEHP were greater in environment at the recycling site than at reference site (industry wastewater for the exposed: 42.43μg/l; well water: 14.20 vs. 0.79μg/l, pond water: 135.68 vs. 0.37μg/l, cultivated soil: 13.07 vs. 0.81mg/kg, p < 0.05 for all). The workers had higher median levels of MDA (3.80 vs. 3.14nmol/ml) and urinary 8-OHdG (340.37 vs. 268.18μmol/mol creatinine) and decreased SOD activities (112.15 vs. 123.82U/ml) than the reference group (p < 0.01 for all). Multivariate analysis revealed that the history of working in waste plastic recycling was an independent risk factor for the increased urinary 8-OHdG levels in the male workers (p < 0.01). The occupational DEHP exposure might contribute to oxidative deoxyribonucleic acid damage in the male workers.