Occurrence and Risk Assessment of Organophosphate Esters in Source Water of the Nanjing Section of the Yangtze River

Abstract

We explored the pollution characteristics, spatial and temporal distribution, ecological risk, and human health risk of organophosphate esters (OPEs) in the source water of the Nanjing section of the Yangtze River. Thirteen OPEs were determined by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. The results showed that twelve OPEs were detected to different extents with total concentrations ranging from 85.21 to 1557.96 ng·L-1[excluding tris (2,3-dibromopropyl) phosphate]. Chloroalkyl phosphate was the main compound and tris(2-chloroethyl) phosphate (TCEP) was the most abundant of the thirteen OPEs, which reached up to 447.08 ng·L-1. Seasonal variation of OPEs showed that the concentrations of OPEs in summer ranged from 220-1557.96 ng·L-1, with the average concentration of 493.78 ng·L-1 being 1.7-2.6 times higher than of that in spring and autumn. An ecological risk assessment showed that tricresyl phosphate and 2-ethylhexyl diphenyl phosphate were associated with moderate or high risks to organisms (algae, crustaceans, and fish). At a high exposure concentration, the total non-carcinogenic risk of OPEs in source water ranged from 4.41×10-3-2.91×10-2, with the highest risk being associated with children aged 0-3 months. The total cancer risk value was 5.88×10-7-3.89×10-6, among which TCEP and Tris(1,3-dichloro-2-propyl) phosphate was associated with a potential risk for children. We conclude that the long-term exposure risk for children of OPEs in the source water of the Nanjing section of the Yangtze River deserve more attention.