Exposure and tiered ecological risk assessment of phthalate esters in the surface water of Poyang Lake, China

Phthalate esters (PAEs) are a class of endocrine disruptors that are produced and used extensively in China. Given its presence in various products, a great quantity of PAEs flows into different aquatic systems each year. Hence, it is important to study the pollution levels and ecological risk of PAEs. This study investigated the distribution and seasonal variation of six priority PAEs in the surface water of Poyang Lake, the largest freshwater lake in China. In the wet season, the mean concentration of the total PAEs was 0.544 +/- 0.173 mu g/L, while the dry season concentration (1.003 +/- 0.451 mu g/L) nearly doubled. The most abundant PAE congeners were di-n-butyl phthalate (DBP), followed by bis (2-ethylhexyl) phthalate (DEHP). To evaluate the ecological risks in Poyang Lake, the predicted no-effect concentrations (PNECs) of four PAEs based on non-lethal effects were derived. For diethyl phthalate (DEP), butyl benzyl phthalate (BBP), DBP, and DEHP, the PNECs were 31.6, 3.30, 2.31, and 0.0210 mu g/L, respectively. The tiered ecological risk assessment showed that DEP and BBP posed no risk in Poyang Lake. Meanwhile, DBP posed a potential risk in Poyang Lake, but the risk of DEHP was unacceptable and requires more actions. Specifically, the probabilities of exceeding the threshold for the protection of 95% of the aquatic organisms (HC5) were 3.30% and 4.43% for DEHP in the wet and dry season, respectively. This study provides an appropriate reference for the surface water management of PAE pollution in China. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Phthalate esters (PAEs) are widely produced and used in China as endocrine disruptors, with a significant amount entering aquatic systems annually. A study in Poyang Lake found that concentrations of PAEs nearly doubled in the dry season compared to the wet season, with DBP and DEHP being the most abundant congeners. The ecological risk assessment revealed that while DEP and BBP posed no risk in the lake, DBP had a potential risk and DEHP had an unacceptable risk that requires further action.