Evaluation of the potential ecological risk of heavy metals in farmland soils in a certain gold mining area, Xiaoqinling

In order to reveal the potential ecological risk grades of heavy metals in soils, the authors used Hakanson’s potential ecological risk index and take the means of heavy metal contents in farmland soils unaffected by industrial and mining operations west of the study area in Xiaoqinling as evaluation reference values to evaluate the potential ecological risk of heavy metals in farmland soils in mining areas on the basis of the previous soil pollution investigation and. The element with the most serious potential ecological risk in farmland soils is Hg, and next come Cd and Pb. The total contribution rate of Hg, Pb and Cd to soil pollution risk is 97.41%, and the contribution rate of Hg alone reaches 84.37%. The soil samples of several elements with high and very high potential ecological risk account for 49.62% of the total samples, with an influence area up to 74.54%. From northwest to southeast in the study area, the degree of potential ecological risk of heavy metals in soils increases dramatically. This spatial distribution is consistent with the distribution of gold ore dressing and smelting in the study area. The consequences of the potential eco-environmental risk of heavy metals in soils have been proved by previous research.