Chemical forms and risk assessment of heavy metals in soils around a typical coal-fired power plant located in the mountainous area
FAN Ming-yi1, YANG Hao1,2, HUANG Xian-fei1,3, CAO Ren-sheng1, ZHANG Ze-dong1,2, HU Ji-wei1,2, QIN Fan-xin1
1. Guizhou Provincial Key Laboratory of Information System of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China;
2. Institute of South China Karst, Guizhou Normal University, Guiyang 550001, China;
3. College of Forestry, Guizhou University, Guiyang 550025, China
In order to investigate chemical forms of heavy metals in soil around the power plant located in Jinsha County, Bijie City, thirty-two surface soil samples were collected and analyzed using the modified Community Bureau of Reference (BCR) sequential extraction procedure. The risks of the heavy metals were evaluated using the potential ecological risk index proposed by Hakanson, the modified grey clustering, and risk assessment code (RAC). The results obtained showed that some differences were found in the spatial distributions of the heavy metals, and the concentrations of all heavy metals (except for Cd and Cr) were higher than the background values in soils from Guizhou. The majority of the heavy metals were primarily kept in residual fractions, while Cd existed mainly in acid soluble and reducible fractions. The results of correlation analysis showed that the correlations among Hg, As, Cd and Ni were significantly positive, while the correlations of Pb and Zn with the other heavy metals were weak. The results from potential ecological risk assessment indicated that the order of ecological risk for the seven heavy metals was Cd > Hg > As > Cu > Pb > Zn > Cr. The average ecological risk index (RI) was 129.72, suggesting a medium ecological risk to local ecological system. The results of modified grey clustering method showed that the pollution level in the west of the power plant was obviously higher than that in the east, and Hg and Cd were the main pollutants. Based on the analysis with RAC method, Cd was of medium risk to the environment (18.17%). Accordingly, Cr and Zn posed low risk, whereas Hg, Pb, As and Cu posed extremely low risk to the environment. In summary, surface soil around the coal-fired power plant was polluted to different degrees by heavy metals, and special attention should be paid to the treatment of Hg and Cd pollution.
范明毅, 杨皓, 黄先飞, 曹人升, 张泽东, 胡继伟, 秦樊鑫. 典型山区燃煤型电厂周边土壤重金属形态特征及污染评价[J]. 中国环境科学, 2016, 36(8): 2425-2436.
FAN Ming-yi, YANG Hao, HUANG Xian-fei, CAO Ren-sheng, ZHANG Ze-dong, HU Ji-wei, QIN Fan-xin. Chemical forms and risk assessment of heavy metals in soils around a typical coal-fired power plant located in the mountainous area. CHINA ENVIRONMENTAL SCIENCECE, 2016, 36(8): 2425-2436.
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