Analysis And Assessment On The Heavy Metal Content And Pollution Of Farmland Soil In A Mining Field Of Guangxi

Mining activity often brings serious environmental and ecological problems, at the same time it is also one of the important sources of soil heavy metal pollution. By mining activities leading to soil heavy metal pollution and potential ecological risk, has received wide attention both at home and abroad. In the12Villages of a typical mining town in Guangxi as the research object, we collected systematically soil samples, and use ICP-AES and other equipment to analyze samples of heavy metal total, analysis of soil heavy metal elements content in characteristics,evaluation of heavy metal pollution in the mining area, and ecological risk assessment. Research on lead-zinc mining area to the prevention of heavy metal pollution has certain theory significance and guiding value, promote environmental protection in mining of metal mines.1. The study of soil heavy metals in profile to the vertical variationed of "poly" features, with soil depth increase, the total amount of heavy metals decreased, possibly due to human activities caused by heavy metal in the surface soil accumulated significant.In the horizontal direction, the6kinds of heavy metals in the soil of the coefficient of variation of the range between0.266and0.928.The use of semi variogram fitting6heavy metal elements of theoretical model were that As for linear model, Cd, Cu, Mn, Pb and Zn were spherical model, coefficient of determination R reached extremely significant correlation.These6kinds of heavy metals, As, Cu and Mn with moderate spatial correlation, reflecting the soil parent material, soil forming factors and soil types and other structural factors and human activity effect.The soil Cd, Pb and Zn is weak spatial correlation, reflecting the fertilization, pesticide, farming measures and other field operations (the influence of human activities).Variability was structural factors and random factors.The use of Kriging interpolation and the method of combining GIS, a visual representation of heavy metals in soil spatial distribution pattern, the different elements of the spatial distribution of a plaque and a banding distribution.2.In the mining areas, soil heavy metal pollution assessment.The first, using single factor evaluation method of mining areas soil heavy metal pollution assessment, pollution degree was PCd> PMn> PAs> PZn> PPb> PCu; Xin Caiyuan soil affected by Cd and Mn pollution is serious, the pollution index was respectively20.69,35.99; Huang Tian cropland soils affected by Cd pollution was serious, the pollution index was5.27;Chao Yang soil affected by As, Cd, Mn, Pb and Zn pollution was serious, the pollution index was respectively6.89,56,5.35,3.95and7.67; Da Ping soil affected by Cd and Mn pollution, the pollution index was respectively10.67and24.60; Tong Keng soil affected by As, Cd, Mn and Zn pollution was serious, the pollution index respectively5.14,136.95,26.83and3.09; Da Shujiao soil affected by Cd and Mn pollution was serious, the pollution index was respectively132.92,4.93; Tie Banshao affected by Mn, Pb and Zn pollution was serious, the pollution index was respectively33.34,72.92,8.81,4.92and8.64; Geng Zhuang soil by As, Cd and Mn pollution was serious, the pollution index is respectively8.83,19.62and15.11; Lao Caiyuan soil by As, Cd and Mn pollution was serious, the pollution index is respectively11.79,12.62and3.13foot; Yan Shanjiao soil affected by Cd and Mn pollution is serious, the pollution index was respectively9.47and8.07; Gao Feng soil by As, CdAnd Mn pollution was serious, the pollution index was respectively6.41,15.84,3.90; Sha Ping soil affected by Mn, Pb, Zn pollution is serious, the pollution index is respectively33.27,60.48,5.89,5.32,10.13.The second, using the multifactorial evaluation,12mine areas pollution degree was Tengkeng> Da Shujiao> Tie Banshao> Shao Ping>Chao Yang>Xin Caiyuan> Da Ping> Geng Zhuang> Gao Feng>Yan Shanjiao> Huang Tian, their combined pollution grade belonged to heavy pollution.The third,using the index of geoaccumulation method on soil heavy metal pollution degree evaluation,6kinds of heavy metals pollution trended:Igeo (Cd)> Igeo (Pb)> Igeo (As)> Igeo (Zn)> Igeo (Mn)> Igeo (Cu), in which12mine areas, As contamination level was very strong, Cd pollution degree was extremely strong, Pb was a strong-strong, Zn, Mn, Cu light, the soil As, Cd, Pb and Zn as the main pollution factor, and the single factor pollution index the results were basically the same; As in Tie Banshao soil cumulative index was to the maximum, Cd in Tong Keng soil index of geoaccumulation was maximum, Cu in Tie Banshao soil index of geoaccumulation was maximum, Mn in Xin Caiyuan soil index of geoaccumulation was maximum, Pb in Tie Banshao soil index of geoaccumulation was maximum, Zn in ShaPing soil accumulation index was maximum.Finally using osculating value method to comprehensive evaluation of pollution status, drow the conclusion:in Dachang field in the12village class of pollution were serious pollution.3.In the heavy metal in the soil of single factor evaluation, evaluation of many factors, osculating value comprehensived evaluation, the evaluation results were roughly the same.Dachang mining area12village farmland soil pollution degree was generally severe, cause soil pollution was the main factor of As, Cd, Pb and Zn, its reason on the one hand with the local separation, washing ore and smelting enterprises are closely related; on the other hand, the long-term wastewater irrigation resulted in the accumulation of heavy metals in soil very serious. And with the help of ecological risk assessment and health risk assessment, the risk grade of strong mining area ecological.To sum up, the mining area soil heavy metal pollution is serious, the local ecological environment has been a serious threat to.