Comparative Study of the Accumulated Effect of Heavy Metals on Soil and Wheat in Xiaoqinling Gold Mining Area

this paper studied the farmland soil and wheat in Xiaoqinling gold mine. Based on the National Standard for Soil Environmental Quality, food safety standards and neighbor-controlling values, the authors used the single-factor-pollution-index method and the Nemero comprehensive-index method to evaluate the acumulative pollution of heavy metals in soil and wheat. By using MapGIS6.7 and the geostatistical methods the spatial distribution and pollution of heavy metals in soil and wheat were investigated. The results show that it is the development of gold deposits that caused the accumulation and pollution of Hg, Pb, Cd and Cu in soil(the cumulative multiple,18.97、8.67、4.50、4.03; the pollution multiple, 4.48、3.50、3.46、3.13). whereas Cr, As and Zn are not obviously accumulated, and not characteristic of pollution elements of the study area. The accumulation of Hg, Pb and Cd in wheat have been obviously affected by human activities, with Pb on the pollution level (the multiple over standard, 2.01). Various forms and total amounts of Cu and Zn in soil were significantly correlated with the content in wheat. The partial morphology and total amount of Hg and As in soil were significantly correlated with the content in wheat. The carbonate Cr was negatively correlated with Cr in wheat. The difference of heavy metals in soil and wheat shows that the judgement of the hazards of heavy metal pollution in farmland soil needs combine the crop effects for correlation analysis and risk assessment. Other factors such as soil, plants, atmosphere and irrigation need to be taken into consideration.