Distribution Characteristics And Ecological Risk Assessment Of PPCPs In Surface Waters Of The Yangtze River

Pharmaceuticals and personal care products(PPCPs)are a new class of trace organic pollutants,which have certain potential risks to the ecological environment and human health.China is a major producer and user of PPCPs.At present,158 PPCPs have been detected in rivers and lakes in different regions of China.The Yangtze River is China ’ s largest river,receiving more sewage discharge,but also an important source of domestic and industrial water.At present,there is a lack of systematic research on PPCPs in the upper,middle and lower reaches of the Yangtze River.Therefore,this paper studies the pollution characteristics of PPCPs in 10 key sections of the Yangtze River from Panzhihua to Nanjing,and discusses the source of pollutants,which is of great significance for pollution prevention and control.In this paper,the concentrations of 58 PPCPs were determined by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry(SPE-HPLC-MS/MS)in 10 key sections of the Yangtze River.The distribution characteristics and temporal and spatial variation of pollutants were studied,and the source analysis and ecological risk assessment were carried out.The results showed that the target PPCPs were detected in different degrees in 10 key river sections in dry season,and two target PPCPs were not detected in all river sections in wet season,which were FMQ and OMP.The average concentration range of ΣPPCPs in dry season was90.0～409.3 ng / L,and that in wet season was 52.5～888.9 ng / L in nine river sections(Wuhan river section was not sampled for epidemic reasons).The concentrations of intermediate 4-AATP and metabolites N-ASMX of CF,CBZ,DCF,MDZ and MMS were relatively high.The PPCPs concentration in the key sections of the Yangtze River was generally at a low level,while the concentrations of STZ,CLI and CBZ were at a high level compared with other basins in China and abroad,and the CIP concentration was at a medium level.The seasonal variation of the concentrations of 58 PPCPs basically showed the rule that the concentration in dry season was higher than that in wet season,and the concentration of tetracycline antibiotics and other individual drugs in dry season was lower than that in wet season.Among the 10 key sections of the Yangtze River,Luzhou section has the highest average concentration in dry season,and Panzhihua section has the lowest concentration.The highest average concentration in wet season was in Nanjing river,and the lowest was in Panzhihua river.On the whole,the concentration of PPCPs in the lower reaches of the Yangtze River in the two seasons was higher than that in the upper reaches of the Yangtze River(except Luzhou River in dry season and Chongqing River in wet season)and the middle reaches.In this study,the correlation between the target PPCPs and TOC content in the key sections of the Yangtze River was not significant.Compared with the middle and lower reaches of the Yangtze River,the untreated sewage discharge or non-point source pollution sources in the key river sections have a greater impact on the distribution of PPCPs.The pollution sources of PPCPs in the middle and lower reaches of the Yangtze River are mostly contributed by sewage treatment plants.In addition,the river sections of Nanjing and Chongqing are greatly affected by medical wastewater discharged by surrounding hospitals and other medical institutions.The ecological risks of 22 PPCPs in the surface water of the key section of the Yangtze River were evaluated by using the risk entropy method.The ecological risks of the surface water of the key section of the Yangtze River were at a low level.Among the 22 PPCPs,CBZ(RQ value range 0.767～8.367)and CF(RQ value range 2.587～37.580)showed medium and high risks in each section of the Yangtze River in two seasons.Seasonally,the ecological risk in dry season was higher than that in wet season,and most of the substances in each river section basically followed this rule.Spatially,the dry and wet periods showed similar spatial distribution patterns,and the ecological risks in the upper reaches of the Yangtze River were significantly higher than those in the middle and lower reaches(except Panzhihua and Nanjing sections).