| Phthalate esters?PAEs?are a class of typical endocrine disruptors which were mainly used as plasticizers for plastics.In recent years,with the mass production and extensive use of plastic products,more and more PAEs were discharged to the environment.The environmental issues about residues level,distribution characteristics,ecological risk and health risk of PAEs attract more and more attention,because they are not easily degradable in the environment with bioaccumulation and chronic toxicity.Poyang Lake is the largest freshwater lake in China,and it is also the most important and direct source of drinking water and production base of freshwater fish in Jiangxi Province.Therefore,a comprehensive research on the composition,distribution and risk assessment of PAEs in the water and fish is of great significance to the environmental management and sustainable development of Poyang Lake.In this study,six PAEs?dimethyl phthalate?DMP?,diethyl phthalate?DEP?,di-n-butyl phthalate?DBP?,butylbenzyl phthalate?BBP?,bis?2-ethylhexyl?phthalate?DEHP?,and di-n-octyl phthalate?DnOP??classified as priority environmental pollutants under the Clean Water Act regulated by the US Environmental Protection Agency?USEPA?were the research object,and a study on the composition and distribution of PAEs in the water and fish body of Poyang Lake,as well as its water quality criteria and risk assessment was carried out.The main conclusions of this study are as follows:?1?The concentrations of the total PAEs in Poyang Lake ranged from 0.265 to 2.058 ?g/L with a mean of 0.736 ?g/L.DBP and DEHP are the most predominant congeners because they are the most abundantly produced and used PAEs.Compared with other rivers and lakes at home and abroad,the concentrations of PAEs in Poyang Lake were at a low level.The distribution of PAEs indicated the significant seasonal variation,the mean concentration of the total PAEs in the dry season?0.984 ?g/L?was twice as high as that in the wet season?0.524 ?g/L?.Rainfull and high runoff occurred during the wet season,which caused the variation.?2?The concentrations of the total PAEs in the fish of Poyang Lake ranged from 144.43 to 695.08 ?g/kg,DBP and DEHP are the most predominant congeners in fish as the same as in water.DMP,DEP,DBP and DEHP were detected in all biological samples,and their bioaccumulation were 188 L/kg,296 L/kg,477 L/kg,and 895 L/kg,respectively,which were positively correlated with the octanol-water partition coefficient?Kow?.?3?The water criteria for aquatic organisms were calculated by species sensitive distribution?SSD?method based on non-lethal toxicity endpoint as 31.5 ?g/L,3.30?g/L,2.31 ?g/L,and 0.0210 ?g/L for DEP,BBP,DBP,and DEHP,respectively.And the water criteria of DMP,DEP,DBP,and DEHP for the protection of human health were derived as 9067 ?g/L,443.3 ?g/L,39.93 ?g/L,and 0.08 ?g/L based on the local exposure factors and bioaccumulations of Poyang Lake.Compared with domestic and international water criteria and standards,such as the US EPA recommended water quality criteria for DEHP was 0.32 ?g/L,the Chinese quality standards and World Health Organization?WHO?suggested that the concentration of DEHP in water must be less than 8 ?g/L,the water criteria for DEHP in this study were lower.It indicated that might be under-protective toward the human and aquatic organism in Poyang Lake basin if the international standards were applied.?4?The ecological risk assessment results show that the pollution level of DEP and BBP in Poyang Lake will not harm aquatic environment,while DBP posed low-risk and DEHP posed high-risk.The health risk assessment of human exposure to edible fish and water were conducted,the results showed that the target hazard quotient?THQ?of DMP,DEP,DBP,and DEHP were far less than 1,indicated that daily drinking water and consumption of fish would not cause non-carcinogenic hazards for human.However,the incremental life cancar risk?ILCR?of DEHP ranged from 4.47 ×10-7 to 4.44 × 10-6,was more than acceptable level of cancar risk(10-6).And the carcinogenic risk for children were higher than adults,resident should control those fish consumptions to avoid the carcinogenic risk from DEHP,suggesting that fish intake do not exceed 7.0 g/d in Hukou and 18.4 g/d in Nanjishan for children.In conclusion,the pollution level of DEHP in Poyang Lake is hazardous to human health and aquatic organisms. |
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