Characteristics And Risk Assessment Of Polybrominated Diphenyl Ethers And Organochlorine Pesticides In Water And Sediment Of The Yangtze River Basin

Persistent Origanic Pollutants(POPs)have great harm to the environment and human health because of their persistence,bioaccumulation potential in the tissues of living and high toxicity.They have attracted widespread attention worldwide.Polybrominated diphenyl ethers(PBDEs)and organochlorine pesticides(OCPs)are the typical persistent organic pollutants in urban and rural areas,which can enter river through surface runoff,atmospheric deposition,sewage discharge,etc.,they have a strong affinity for suspended particles and subsequently settle down into sediments under gravity.So it is of great significance to study the pollution characteristics of PBDEs and OCPs in water and sediments of river.In this study,water and sediment samples were collected from 41 national key monitoring sections along the whole Yangtze River in October 2014.The concentration distributions,composition characteristics,pollution sources and possible environmental risks of PBDEs and OCPs in the Yangtze River multi-environment mediums were comprehensively studied.The main results of this study were as follows:1.All kinds of PBDEs and OCPs congeners were detected in water and sediment samples of the Yangtze River.The concentrations range and average value of PBDEs,HCHs,DDTs in the water were0.33?10.36 ng/L(3.49 ng/L),91.03?152.13 ng/L(112.03 ng/L),11.71?54.53 ng/L(31.43 ng/L),respectively.The concentrations of PBDEs,HCHs,DDTs in the sediments were0.18?6.75 ng/g(1.57 ng/L),4.75?45.12 ng/g(15.47 ng/g),0.81?5.95 ng/g(2.54 ng/g),respectively.Compared with other major rivers and regions at home and abroad,the concentrations of PBDEs,HCHs and DDTs in the water were at medium or high levels,the HCHs in the sediments were at medium level,while PBDEs and DDTs in sediments were at relatively lower levels.2.The concentrations of PBDEs and HCHs in the middle and lower reaches of the Yangtze River basin are higher than in the upstream.The concentration of PBDEs of water in the Dongting Lake and the Xiangjiang River and HCHs of water in the Jialing River and Dongting Lake are relatively higher than the other tributary waters.The sediments are heavily polluted by PBDEs such as the Jialing River and Hanjiang River,and the HCHs in the Wujiang River and Jialing River have high concentrations.The concentration of DDTs in the downstream of water is the highest,while that in the midstream of sediments is the highest.The concentration of DDTs of water in the Dongting Lake and the Xiangjiang River are relatively higher than the other tributary waters.The sediment samples of the Xiangjiang River and Huangbai River are polluted heavily by DDTs,relatively.3.According to the analysis of the sources of pollution of PBDEs and OCPs,DecaBDE(Commercial)are the most widely used products in the Yangtze River basin.In addition,OctaBDE(Commercial)and PentaBDE(Commercial)have also been used in the Yangtze River Basin.Most of the HCHs in the water are mainly from the use of industrial HCH products or the mixture of HCH products and lindane.The DDTs in water samples are mainly from industrial DDTs,while a few samples have input of dicofol.The HCHs in the surface sediments mainly come from the use of lindane,and 80%of the samples contain the input of dicofol.4.Redundancy analysis between POPs homologues in water,sediment samples and their influencing factors all showed that GDP,the second industry,and the precipitation have a certain positive correlation with some PBDEs homologues in the river.HCHs and DDTs in the environment are positively affected by per capita output grain,rural population,and GDP.5.The ecological risk assessment method and the health risk assessment model method all indicated that the potential ecological risk of pentaBDE is at a moderate level.DecaBDE poses a relatively high threat to the environment.y-HCH poses a certain degree of ecological risk to the environment.There is a potential carcinogenic risk for OCPs in water bodies.The health risk level of ingestion pathways is as follows:PBDEs and OCPs in water,ingestion>dermal contact,PBDEs in sediments,inhalation>dermal contact,OCPs in sediments,ingestion?dermal contact>inhalation.For PBDEs and OCPs,children have greater potential health risks than adults.