| Although Zhijin country of Guizhou was rich in coal resources, the heavy metals in the coal was released into the environment. In the process of mining, heavy metals were released into the surrounding environment through waste water or dust.The heavy metals in the environment spread into the soil and crops through dust and sewage irrigation, at last enter into the body through the food chain, so it caused human body health risks directly or indirectly. In this article,soil, rice and corn samples were selected in coal mining area of YZ,SM,SH,XF,HF. Soil samples were collected to determine total concentrations of Pb, Cr, Cd, Hg, As, Cu, Zn,Ni.Rice and corn samples were collected to determine total concentrations of Pb,Cr,Cd,Cu,Zn,Ni by Atomic absorption spectrometer and Atomic fluorescence spectrometer. To evaluate the status of heavy metals in soil and crops, the study used the single factor pollution index method and comprehensive pollution index method to evaluate the contribution of compound pollution and heavy metals compound pollution of coal mining area based on the background level of heavy metals of Guizhou and Soil Environmental Quality Standards(GB15618-1995). Combining content detection data and health risk assessment model of heavy metals in crops seeds to evaluate human health risks.The main results as follows:(1) According to the second grade value from Soil Environmental Quality Standards(GB15618-1995), the single factor pollution index showed that the soil was not polluted by Pb, Cr, As in mining area of YZ, SM, HF, SH, XF and was polluted by Hg、Cd、Ni、Cu, especially Hg, which contributed more to soil pollution and it had significant index with 2.31, followed by Cd, Ni, Cu. Based on the background level of heavy metals of Guizhou, the soil was not polluted by Pb, Cd in coal mining area of YZ, SM, HF, SH, XF and was polluted by Zn、Cu、Ni、Hg, especially Hg, which contributed more to soil pollution and it had significant index with 6.44, followed by Cu, Ni, Zn. Except SM, the rest four mining area was not polluted by As. SH and XF mining area was polluted by Cr.(2) According to the second grade value from Soil Environmental Quality Standards(GB15618-1995),comprehensive pollution index showed that it had compound soil Heavy metals index and the value was 1 to 2 in YZ、SM、HF、XF, which was in a light pollution level. The value in SH was from 2 to 3, which was in mid-level pollution. Based on the background level of heavy metals of Guizhou, comprehensive pollution index was more than 3 in YZ、SM、HF、SH、XF, which were in heavy pollution level, and the degree of pollution was SH>YZ>SM>HF>XF.(3) The average p H was less than 7 and soil was acidic. The p H in YZ and SM was positively ralated to the content of Ni and was a negative correlation to Cd in SM, and the heavy metals of the rest of coal mining areas were not correlated. Pb, Zn, Cu affected by the same factors in YZ. Cd, Ni, Hg, Cr, As, Zn and TP were affected by the same factors in SM. Ni, As, Pb, Cd, Cu, Hg and TP affected by the same factors in SH. Cd, Ni, As and Hg were affected by the same factors in XF. Cu and Zn were affected by the same factors in HF. If the impact factors were the same, they probably had same possible sources.(4) In rice and corns, the concentration ability of Cr was the max, enriched coefficient were 3.01 and 3.39, which shown that enrichment ability of corns were better than rice for Cr. The single factor pollution index value of rice and corns were 9.84 and 7.55 at a heavy pollution level, Ni was the strongest contribution to the compound pollution in rice and corn, followed Cr. Comprehensive pollution index of Cr were larger than 3, the value in rice and crops were 7.20 and 6.47, so they were serious polluted by Cr, rice was seriously polluted than corns. The HQ were less than 1, which shown that eating corn and rice alone with some heavy metals did not have influence on human body health. The HI of rice and corns werewas more than 1, there was a big risk to human health and eating rice had more health risks. |
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