| This study selected the Fuquan Lead/Zine Mine in Hanyuan County for the study area, surveyed and analyzed the spatial variability character of heavy metal content in soils which were in the vicinity of the Lead/Zine Mine, and gave the environmental pollution assessment of soil heavy metal by the N. L. Nemerow pollution index, probability kriging and sequential indicator simulations. At last, and then made reasonable countermeasures and suggestions for the renovation of heavy metals in soil. The result showed that as follows:(1) The content of the three kinds o heavy metals in soil in the study area had the large variation, the average total content of Cd was 10.92±12.22 mg kg-1, the average available Cd was 1.47±1.39 mg kg-1, the average total content of Pb was 657.92±1031.87mg kg-1, the average available Pb was 102.04±89.75 mg kg-1, the average total content of Zn was 1549.06±1915.55 mg kg-1,the average available Zn was 80.02±59.95mg kg-1. The average total content of Cd, Pb and Zn all exceeded the standard compared to the second level of the National Soil Environmental Quality Standard (GB/T 15618-1995) .The pollution of the heavy metal in soil were very serious , the maximum of the total content of Cd was more than 98 times of the standard, the maximum of the total content of Pb was more than 14 times of the standard, the maximum of the total content of Zn was more than 31 times of the standard, but the available content of heavy metals in soil were generally low.(2)The impact order of the spatial variability to the three kinds of total heavy metals contents in soils which were caused by the process of mining was Zn> Pb> Cd, the main change occured in NE-SW. The spatial distribution of the three kinds of total heavy metal appeared as gobbets, the highest value existed in the northeast part where the mine tailings accumulates and then in the farmland soil which are in the vicinity of lead/zine mine, the lowest value mainly exists in the northwest part.(3)The impact order of the spatial variability to the three kinds of available heavy metals contents in soils which are caused by the process of mining is Zn> Pb> Cd. The spatial distribution of the three kinds of available heavy metal appeared as belts, the main change occurs in NW-SE, and gradually descends from northwest to southeast. The highest value exists in the northwest part of the mine , and the lowest value mainly exists in the southeast part.(4)The analyses about correlation between total and available content of heavy metals showed the strong positive correlation, such as the Cd and Pb , Cd and Zn, Pb and Zn, they all had the highly significant correlation, but the available content of heavy metals and their corresponding total content of heavy metals had the less correlation. The analyses about correlation between content of heavy metals and the physical and chemical properties of soils showed that, the total content of heavy metals did not have the significant correlation with the physical and chemical properties of soils, but the available content of heavy metals had the negative correlation with the pH of soil, especially the available content of Cd and the available content of Pb had the significant negative correlation with the the pH of soil and the available content of Cd had the significant positive correlation with clay content in soils.(5)Environmental assessment of heavy metals using single index method showed that the total content of heavy metals pollution effect order was Cd>Zn>Pb. For the available content, the pollution of Cd was serious , available content of Pb and available content of Zn did not reach the pollution level. Environmental assessment of heavy metals using complex index method showed that the complex index of total content of heavy metals and available content were 69.77 and 9.48, both of them beyond the heavily polluted level.(6)Environmental assessment of heavy metals using probability kriging showed that the exceeded probability for total content of heavy metals was gradually decreasing from the northeast to the southwest as the formant of gobbets and belts in the study area. The exceeded probability for available content of heavy metals was gradually decreasing from the northwest to the southeast as the formant of belts.(7)The sequential indicator simulations for total content of heavy metals showed that the highly exceeded probability occurred in the northeast part and lowly exceeded probability occurred in the southwest and south part of the study area. The sequential indicator co-simulations for available content of heavy metals showed that the highly exceeded probability occurred in the west, southwest and northwest part of the study area, and the lowly exceeded probability occurred in northeast of the study area.(8)In order to achieve the environment renovation goal in cost-effective, the major measures werereducing or cutting off the sources of pollution and adopting the plants renovation.
|
PDF Full Text Request