Soil Heavy Metal Pollution Assessment Of Dawu Baiyun Gold Mine Mining Area

The mining and smelting of non-ferrous metal caused serious pollution and destruction to the environment,the soil of diggings that polluted by heavy metal is a colossal security risk.In the past more than ten years of development,non-ferrous metal acquisition leave many problem to Dawu county,what resulting in Dawu county was included in the heavy metal key prevention and control area in the12 th five-year plan.In order to know the pollution episodes of Dawu baiyun gold mining area,fourteen soil sampling points and twenty samples was gather inthe tailings storage,processing zone,50 m downstream of the tailings,100 m downstream of the tailings and tailings stockpiling place on the basis of the data collection and field reconnaissance.Flame atomic absorption spectrophotometer and atomic fluorescence photometer was used to the determination of copper,zinc,lead,cadmium,mercuryand arsenic content ofsoil samples,and the test result was analyzed in this paper.The result of the test was managed by application of matlab software interpolation processing and drawed the distribution of heavy metal element contour map to the mining area through origin,at the same time this paper analyzed the surface layer of soil(0~20cm)in 6 kinds of heavy metal distribution characteristics and distribution laws.Then the author analysied the tailings of different depth 1#~4# sample point of the vertical distribution of heavy metals in the soil samples analysis.And single factor index method and nemerow index and potential ecological risk index was applyed to evaluate heavy metal pollution situation of the mining area surface soil(0~20 cm).The main conclusion ofthis paperwas summarized as follows:(1)Dawu baiyun gold mine mining area of soil heavy metal accumulation quantity are higher than the average content of soil element background values in hubei province,4# sampling points of the tailings in the highest total content of heavy metals,tailings storage times,other sampling area of soil heavy metal total content because of different sites have certain differences,each block of heavy metal of mining area content in order for the tailings storage > tailings stockpiling place >50m downstream of the tailings > processing zone >100m downstream of the tailings.From the point of variation coefficient,the variability of each heavy metal element were bigger,the variation coefficient was 19%~66%,moderate intensity variation.(2)Based on the distribution of each heavy metal element content contour map analysis the highest level of heavy metals pollution is tailings.According to Exhibition standards(Provisional)(HJ350-2007)each sampling point of heavy metal copper,zinc,lead,cadmium,mercury and arsenic in A-B level,there is pollution in the soil of mining area environment.(3)By measuring 1#~4# sample point 6 of samples with different depth of soil heavy metal content and analysis of results,opper,zinc,lead,cadmium and arsenic in the six kinds of heavy metal elements in the vertical direction show similar distribution,its content increase with depth general downward trend after rising first;Each sampling point mercury content of samples with different depth,and with the increase of the depth has a tendency to rise.Dawu baiyun gold mine tailings of copper,zinc,lead,cadmium and arsenic in five kinds of heavy metal elements are mainly concentrated in the shallow soil,different depth of sample Hg accumulation degree difference.(4)Through single factor index method to evaluate Dawu baiyun gold mine soil,mining the main pollutants of the soil,cadmium,mercury and lead pollution degree is higher,the pollution scope is bigger;Through nemerow index to evaluate Dawu baiyun gold mine soil analysis,concluded five sampling area of heavy metal pollution levels are high levels of pollution,the sort of each area is the tailings storage > tailings stockpiling place >50m downstream of the tailings > processing zone >100m downstream of the tailings.Single pollution index of the largest heavy metals are cadmium in different sampling area,cadmium in Dawu baiyun gold mine mining area of soil heavy metal pollution of main heavy metal element;Through the potential ecological harm index method to evaluate Dawu baiyun gold mine soil analysis,obtains the sampling point of comprehensive index of potential ecological harm of heavy metals are severe pollution.The sorting for heavy metal potential ecological harm coefficients is cadmium>mercury>arsenic>lead>zinc>copper,Dawu baiyun gold mine mining area of ecological harm degree of the largest in the soil heavy metal cadmium,from 6 kinds of heavy metals and the potential ecological harm,Dawu baiyun gold mine mining area of soil heavy metal has the very high ecological risk,the management of mining area soil environment is imminent.