Organophosphate Flame Retardants in Soils of Zhejiang Province, China: Levels, Distribution, Sources, and Exposure Risks

Organophosphate flame retardants (OPFRs) are an emerging class of pollutants. In this study, 62 soil samples were collected from Zhejiang Province China, and screened for 8 typical OPFRs. All compounds were detected in soil at 100% detection frequency, except for triethyl phosphate (TEP) compounds (93.6%). The sum of the eight OPFR concentrations ranged from 9.15 to 132 ng/g dry weight (dw), with mean and median values of 24.9 and 19.0 ng/g dw, respectively. Triphenyl phosphate (TPHP) was identified as the most abundant analog, with a median concentration of 9.94 ng/g dw, followed by tris(2-ethylhexyl)phosphate (TEHP). Significantly higher OPFR concentrations were detected in northern Zhejiang; concentrations decreased sharply from the north to the south. OPFR concentrations in soils from cities or economically developed counties were much higher than those from rural areas. OPFR sources in Zhejiang Province mainly originated from PVC-made products and traffic emissions. Dermal absorption of OPFRs via soil was the primary pathway for human exposure. Health risks due to exposure to OPFRs through soil ingestion were found to be negligible.