Occurrence and Human Exposure Risk Assessment of Organophosphate Esters in Drinking Water in the Weifang Binhai Economic-Technological Development Area

Abstract

Concentrations and composition of six organophosphate esters (OPEs) in drinking water in the Weifang Binhai Economic-Technological Development Area were detected by solid phase extraction-gas chromatography-triple quadrupole mass spectrometry (SPE-GC-MS/MS). The correlations of OPEs in drinking water and pooled serum samples from the Weifang Binhai Economic-Technological Development Area were analyzed. The health risk posed by OPEs in drinking water was evaluated using the health risk assessment model recommended by the United States Environmental Protection Agency (USEPA). The results showed that ∑6OPEs concentrations in the tap water samples ranged from 162-253 ng·L-1, while ∑6OPEs concentrations in groundwater ranged from 3.52-13.9 ng·L-1, two orders of magnitude lower than that in the tap water. Tris(2-chloroethyl)phosphate (TCEP) was the dominant OPE in the tap water samples, with the median level accounting for 94.81% of the ∑6OPEs. Triphenyl phosphate (TPhP) was the dominant OPE in groundwater, with the median level accounting for 47.55% of the ∑6OPEs. The composition of OPEs in the human mixed serum collected in 2011 and 2015 was strongly correlated with that in the tap water (r=0.990, P<0.01 and r=0.997, P<0.01, respectively). This indicates the significant contribution of OPEs in drinking water to OPEs in human serum. The daily intake (DI) of OPEs via drinking water was 0.26-7.48 ng·(kg·d)-1 and the non-cancer risk hazard quotient (HQ) of OPEs in drinking water ranged from 10-5.81-10-2.43, indicating a negligible non-cancer risk to the local residents exposed to OPEs through drinking water. The carcinogenic risks posed by TCEP in drinking water ranged from 10-8.82-10-6.79, which was lower than the theoretical threshold (Risk=10-6.00), while the carcinogenic risk of TCEP in tap water was higher than that in groundwater.