Distribution Characteristics and Source Identification of Organophosphate Esters in Key Waters Areas of Taihu Lake

Organophosphate esters (OPEs) are ubiquitous in the environment and pose potential risks to ecosystems in that they produce cytotoxicity, genetic toxicity, developmental toxicity, neurotoxicity, and the endocrine disrupting effect. This study aimed to investigate the distribution, sources, and ecological risk of thirteen OPEs in industrial wastewater, influents and effluents of wastewater treatment plants, and the surface waters of key areas (Changzhou City) in Taihu Lake. The results showed that ∑OPEs in industrial wastewater ranged from 91.70-840.52 ng·L-1. The profiles varied from different industries; however, tris (1-chloro-2-propyl) phosphate (TCPP), triethyl phosphate (TEP), and tris (2-chloroethyl) phosphate (TCEP) were the dominant compounds. The ∑OPEs from the wastewater treatment plants were relatively higher, ranging from 1859.59-2778.57 ng·L-1. They are rather resistant to traditional wastewater treatment techniques. The removal rate of ∑OPEs, aryl OPEs, and chlorinated OPEs was 14.97%, 97.91%, and 4.37% (for W1) and 17.32%, 90.83%, and 5.40% (for W2), respectively. The concentration of OPEs in the surface water was in the range of 219.47-689.85 ng·L-1, which was lower than that in wastewater. In addition, TEP, TCPP and TCEP predominated in the surface water samples. A principle component analysis (PCA) indicated that the industrial wastewater, emissions of vehicles, and the release of building materials may be the main sources of OPEs in the study area. A risk quotient was used to assess the ecological risk of OPEs to aquatic organisms in the surface water. Most of the OPEs showed low ecological risk, but 2-ethylhexyl diphenyl phosphate (EHDPP) posed a moderate risk in some sites, and the possible ecological effects caused by the OPEs should not be ignored in the key areas of Taihu Lake.