| River pollution has become more serious with fast development of economy recently.Heavy metals is one of dangerous contaminants because of its toxicity and persistence,which cause a serious threat to the environment and human health.Kuye River is one of the most important rivers in Yellow River areas,which was contaminated.The characteristics of heavy metal(As,Cu,Pb,Zn,Cd,Cr,Co,Mn)contamination in Kuye river surface sediment was analyzed and researched.Results from the study can be seen:(1)The average content of Cr,Mn,Co,Cu,Zn,As,Cd,Pb are 289.59,1471.91,16.68,56.01,172.86,33.53,1.08 and 51.92 mg/kg in the surface sediment of Kuye River.All the contents of heavy metals in Kuye River were higher than soil background values of Northern Shaanxi,that indicates the coal mining area and non-coal mining area were all affected by heavy metals.(2)The surface sediment of Kuye River mainly is particle size composition <250μm.There is a certain correlation between Cr,Co,As,Cd,Pb and particle size composition 50-100 μm,Mn,Cu,Zn and particle size composition 100-250 μm,(3)The average content of Cr,Mn,Cu,Zn in the coal mining area are higher than non-coal mining area,which indicates coal mining has a certain infect on Kuye River.The variance coefficients of heavy metals in coal mining area were mostly lower than non-coal mining area,which indicates non-coal mining area received more threatening forces.(4)The result of Nemerow Index method,Pollution Load Index and ecological risk index is thatthe coal mining area of Kuye River are seriously polluted by Cr,Cd,Mn and the non-coal mining area are seriously polluted by Cr,As,Cd.The pollution level of Kuye River is in middle or upper level with Cd pollution is the main reason.(5)Coal mining and its waste,factory around Kuye River and return water of farmland irrigation containing pesticides and fertilizers can be the main sources of pollution.Their contribution respectively are 41.304%,27.991% and 14.566%. |
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