Urinary Excretion of Phthalate Metabolites in School Children of China: Implication for Cumulative Risk Assessment of Phthalate Exposure

We analyzed 13 metabolites of 9 phthalates in urine of 782 Chinese school children aged 8-11 years and estimated the daily intake for phthalates based on urinary metabolite levels. The daily intakes were compared with acceptable intake levels to calculate the hazard quotient (HQ) for single phthalate. Finally, the cumulative risk for each child was assessed by means of a hazard index (HI) which is the sum of HQs. Overall, 11 metabolites were found in at least 85% of the urine samples with the highest median concentration of 47.1 ng/mL (93.4 mu g/g creatinine) for mono-n-butyl phthalate (MnBP). Monooctyl phthalate (MOP) and monoisononyl phthalate (MiNP) were not detectable. The cumulative risk assessment covering di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), di-isobutyl phthalate (DiBP), and butyl-benzyl phthalate (BBzP) demonstrated that 19.8% (volume model-based) and 40.3% (creatinine model-based) of the children exceeded 1 for the HI based on tolerable daily intake (TDI) values (considered as potential adverse antiandrogenic effect). Furthermore, at least 36% of the children from the manufacturing-intensive region had a HI higher than 1. The results indicate that Chinese children are widely exposed to phthalates and those from manufacturing-intensive regions are probably at a high risk of cumulative phthalate exposure.