黔西南某农用地土壤重金属风险评估与来源解析.

[Objective] In order to understand the content characteristics and ecological risk of heavy metals in agricultural soils in small-scale areas of karst regions, the present paper provides reference for the utilization of land function and the protection of cultivated soil environment. [Method] A total of 27 sites were laid on soil on agricultural land in the southwestern of Guizhou Province, samples of surface soil ( 0 - 20) cm were collected, and 8 heavy metal elements such as pH and Cd, Hg, As, Pb, Cr, Cu, Zn and Ni were analyzed and determined. The 'Soil Environmental Quality-Soil Pollution Risk Control Standard for Agricultural Land' (GB15618 - 2018) was used as the evaluation criteria to analyze its distribution characteristics, ecological risks and sources. [Result] The results showed that the soil pH in the study area was 5. 46 to 8. 07, and the average contents of heavy metals Zn, Cr, Pb, Ni, As, Cu, Cd and Hg were 154. 24, 153. 71, 64. 25, 61. 76, 50. 38, 49. 86, 0. 41 and 64. 25 mg/kg, respectively. The soil pollution index of agricultural land in the study area was 1. 68 and 1. 38, respectively. The hazard index (IR) value of 8 kinds of heavy metals was 69. 00, which was less than the limit of ecological hazard (IR = 150) . Cd and Pb, Hg and As, Cu, Zn, Ni, As and Cu, Zn, Ni, Cr, Cr and Cu, Zn, Ni, Zn and Ni have homology respectively, and there is compound pollution. The results of the main component analysis show that As, Hg, Cr, Cu, Zn, Ni have a higher load in the first main component, the variance contribution rate is 57. 565%, the content is mainly caused by the long-term application of heavy metal fertilizer; Cd and Pb have higher load in the second principal component, and their variance contribution rate is 80. 277%. The higher content is mainly due to the higher content in the parent material. [Conclusion] The soil pH of agricultural land in the study area is 5. 46 - 8. 07 which has been polluted by As and Cd to different degrees. Cr and Ni pollution is still clean range; Hg, Pb, Cu and Zn are in the clean range. The pollution level is slight ecological hazard [ABSTRACT FROM AUTHOR]