Organophosphate esters in Chinese rice: Occurrence, distribution, and human exposure risks

Dietary intake is a crucial pathway of organophosphate esters (OPEs) exposure for human. However, information about the exposure risk of OPEs via rice consumption is still largely unknown. In the present study, a total of 234 rice samples from 25 provinces or city of China were collected and the concentrations of 24 OPEs were determined. Sixteen OPEs were detected in these rice samples and each rice sample was contaminated with at least 5 OPEs, indicating a ubiquitous occurrence of OPEs in Chinese rice. Moreover, the concentrations of Σ16 OPEs ranged from 1.46 to 552.65 μg/kg dry weight (dw), with a mean value of 64.74 μg/kg dw. For the composition profile of OPEs, three Cl-OPEs, including tris(2-chloroethyl) phosphate (TCEP), tri(2-chloroisopropyl) phosphate (TCIPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), accounted for the highest proportion of Σ16 OPEs. For the spatial distribution of OPEs, although obvious spatial variations were observed among the 25 provinces or city, no obvious variations were found among the six rice-cultivating regions of China. Additionally, estimated dietary intakes (EDI) values of the 16 OPEs for adults and children were 1105.24 and 1399.13 ng/kg bw/day, respectively, under the high intake scenario. The hazard indexes of the 10 OPEs were 0.108 and 0.137 for adults and children, respectively. The risk assessment results indicated that Chinese adults and children did not suffer significant adverse effects from OPEs via rice intake.