Research And Evaluate On The Heavy Metals Pollution Characteristics Of The Landfill Soil

This paper selected the soil surrounding a landfill as the research object, through field sampling and laboratory determination, detected the content of Cu、Pb、Zn、Cr in soil. Based on the test results. and combined with single factor pollution index^ Nemerow pollution index、the cumulative index and fuzzy mathematics method, assessed the heavy metal contamination of soil. The results show that:(1) The variation range of soil pH value in surface region was 7.48 to 8.47, the average value is 7.94, the soil is alkaline. Cu, Pb, Zn appeared the phenomenon of accumulation, the content was higher in individual soil samples, but the content did not exceed the 《Soil Environmental Quality Standards》 (GB15618-1995) three standard limits; content of Cr is low, no accumulation phenomenon occurred(2)In the horizontal direction, with the increase of distance, contents of the four heavy metals appeared to decrease; in the vertical direction, with the increase of soil depth, the contents of heavy metals in soil decreased gradually. According to the calculation results of correlation coefficient:there is a significantly positive correlation between Cu, Pb, Zn, which can inference that the excessive is caused due to the existence of the landfill; there is a negative correlation between Cr and the other three heavy metals, and contents of Cr did not exceed the background values, so the landfill did not cause Cr pollution.(3) The single factor pollution index results showed that:in the 30 sampling points, the points of slightly Cu pollution is two, highest Cu pollution index was 1.56; the points of slightly Pb pollution is three, the maximum Pb pollution index was 1.46; the points of slightly Zn pollution is three, moderately Zn polluted sampling number was three, the maximum Zn pollution index was 2.52.(4) The Nemerow pollution index results shows that:soil was lightly polluted within range of 100m distance to the landfill, within 100-500m was warning area,500m outside the landfill is not polluted by heavy metals. Contamination in the region, the major pollution was Zn, there also had a little amount of Cu and Pb pollution, heavy metal Cr does not appear.(5) The index of geoaccumulation showed that:the pollution level sorting of heavy metal elements in the regional soil was Zn> Cu> Pb> Cr. According to the accumulation index averages, the pollution degree of heavy metals did not reach the moderate pollution in 30 sampling, the overall degree of soil heavy metal pollution is light.(6) Through fuzzy mathematics method knew that:the quality evaluation grade of landfill surrounding soil was grade 2 and 3, indicating that the soil heavy metal pollution has appeared, but the pollution degree is light. Soil pollution in southeast was slightly worse than that in northwest, the reason may be wind.