Study On Health Risk Assessment Of Water Quality Of Urban Water Sources

Urban water sourcesare the vital source of residents' drinking waterand production water,and itswater quality is directly related to thequality of residents' life.In addition,the environmental pollutantswhich flowed intowater sources can accumulatein human bodyvia ingestion and skin absorportion pathway,causing heavily damage to human health.Therefore,the health risk assessment of water quality of urban water sourceshas great significance to the protection of water sources,preventionof water pollution and epidemics.The health risk assessment procedure water quality of urban water source contains hazard identification,exposure assessment,dose-response relationship evaluation and risk characterization.In this paper Yangmu reservoir in Liaoyuan city of Jilinprovince was taken as an example.The field investigation,water sampling,indoor experiment,correlation analysis,principal component analysis and cluster analysis were used to determine the water quality of Yangmu reservoir,pollution status and possible pollutionsources.The carcinogenic and non-carcinogenic risk of 8 trace elementsincluding Cd,Pb,Cu,Se,Cr,Zn and Mn and 9 organochlorine pesticidesincludingp,p?-DDD?p,p?-DDE?p,p?-DDT?Aldrin?Dieldrin??-HCH??-HCH??-HCH and ?-HCH in the Yangmu reservoir were evaluated by health risk assessment methods of water quality of urban water sources,which includedeterministic evaluation method,fuzzy method and probability theory method,respectively.And environmental protection measures of Yangmu reservoirs were put forward.The studyshows:(1)The water is very clean and transparent in Yangmu reservoir,and its shore growsaquatic plants.There are fishes in water,and no odor and suspended solids in it.According to the investigation of Yangmu reservoir,it is found that the main pollution sources were life pollution,agricultural non-point pollution and livestock breeding pollution.The content of total phosphorus in Yangmu reservoir was 0.130 mg/L and the content of Mn was 0.284mg/L through water sampling and indoor experiment,which were higher than the standard values,but the water quality did not varysignificantlybetweendifferent seasons.In addition,the trace elements As,Cd,Pb,Cu,Se,Cr,Zn and Mn in Yangmu reservoir could be influenced by anthropogenic sources,especially trace element Mn.(2)The HQ valuesof 8 traces elements and 9 organochlorine pesticides were lessthan 1 or less than 1 with a great probability,so there is low noncarcinogenic risk.And the carcinogenic risk of As reached 4.070E-05,which was higher than standard value 1.000E-06 adopted by Swedenand Netherland,similar to standard value 5.000E-05 recommended by the International Radiation Protection Committee,and lower than standards value 1.000E-04 used by the US Environmental Protection Agency.In addition,the carcinogenic risk of organochlorine pesticide ?-HCHwas 3.280E-06,which also exceeds the standard values of Sweden and Netherlands,but is lower than the US Environmental Protection Agency's standard value.Futhermore,the risk of trace elements and organochlorine pesticides in Yangmu reservoir is different for different age groups,and the risk increase first and then decrease as the age increasesfor populations under 18 years old.The risk value is maximum for1-2years of ageand the value is minimum for 15-18 yearsof age,while for populationsover 18 years old,the risk is constant and the risk value is between the maximum risk value and the minimum risk value because the exposure parameters are constant.(3)Environmental protection measures for urban water sources mainly include non-engineering measures and engineering measures.Andin view of the contents of total phosphorus,Mn in Yangmu reservoir and the health risk of As,it is suggested that the measures of source control,ecological protection and biological purification should be adopted to reduce the content of total phosphorus and Mn as well as therisk of As.All measures can lay the foundation for the protection of water sources and the promotion of public health.