The Pollution Characteristics And Source Apportionment Of Heavy Metals In Bengbu Section Of Huaihe River

Huaihe River?Bengbu Reach?,a typical river in Anhui Province,is one of the main drinking water sources of the resident population.Because of the long-term acceptance of industrial wastewater,emissions of heavy metals cause serious harm to environment,which have threatened the safety of local drinking water.Preliminary studies have largely focus on COD,NH3-N and other conventional pollutants,while ignoring the toxic pollutants of heavy metals.This paper explores the content and spatial distribution of heavy metal pollution in surface water and sediments.Samples were selected at 20 sites along the Huaihe River?Bengbu Reach?from the main stream and main tributaries.The content of 12 heavy metals?As,Hg,Al,Mn,Fe,Cr,Cu,Zn,Pb,Ni,Cr?VI?,Cd?in surface water and 8 heavy metals?Cr,Zn,Cu,Ni,Cd,Hg,As,Pb?in surface sediments were measured.Based on these obtained data,the potential human health risks associated with exposure to heavy metals in the surface water through drinking water and the skin contact was conducted using U.S.Environmental Protection Agency?EPA?recommended method in this paper.To evaluate the ecological risk of sediment environment,Hakanson potential ecological index and the geoaccumulation index were applied.Furthermore,multivariate statistical analysis methods including correlation analysis and principal component analysis were used to identify the potential pollution sources,which can provide basis for water environment treatment in Bengbu City.The results of this research are shown below.?1?The heavy metal of Cu,Zn,Pb and As in Huaihe River?Bengbu Reach?can almost meet environmental quality standards for Grade I surface water.The partial content of Fe and Mn exceeded a little more than the limit for supplementary item of centralized drinking water source.Partial content of Hg not attaining the quality standards for Grade V.The content of Pb,Hg in surface sediments at the main Huaihe River?Bengbu Reach?went far beyond the Soil Environmental Quality Standard,Cr has a content equivalent to the standard and Ni,Cu,Zn,Cd,As were far below the standards.?2?The potential human health cumulative risks of all 20 sampling sites along the Huaihe River?Bengbu Reach?have exceeded the standard(1.0*10^-6a^-1)recommended by Swedish EPA,Dutch Ministry of Infrastructure and the Environment and Royal Society.Drinking water is the major route of human exposure to heavy metals and carcinogens were major sources of human health risk.The degree of health risk of heavy metal decreases in the order of As>Pb>Fe>Al>Mn>Cr>Cu>Zn>Hg.?3?The mean potential ecologic risk values of the heavy metals in surface sediments showed that Hg pose strong ecological risk?level IV?.Other heavy metals including Cr,Zn,Cu,Ni,Cd,Hg and As have relatively low potential ecologic risk values,and are thus considered to be moderately ecological risk?level I?.Based on the Igeo of target heavy metals,the surface sediments collected from the study area can be approximately categorized as unpolluted with Cr,Zn,Cu,Ni,Cd,Hg and As,and moderately polluted with Pb.The degree of heavy metal pollution decreases in the order of Pb>Cr>Zn>Cu>Ni>Cd>Hg>As.?4?Based on multivariate statistical analysis,main sources with corresponding cluster elements can be identified.Fe pollution in water sources may originate from plating or metal smelting and rolling process.Mn pollution in water sources originated mainly from natural processes such as geochemical changes.Excessive heavy metals Hg and high-risk As in surface water were derived from metals mining and dressing and chemical industry.While in surface sediments,Hg with strong ecological risk mainly comes from chemical fertilizer and pesticide.Chemical industry,non-metallic mineral product industry and battery industry are the main source of Pb pollution.