Objective The effect of tailings on the soil quality and crop growth of surrounding farmland in Laoyaling, Tongling, Anhui Province, was studied to provide a reference for heavy metal pollution risk and safe use of land in this area.

Method Four farmland sample sites were set up by taking Laoyaling tailings as the starting point and taking 1km to the southeast as the spacing, which were recorded as NT0, NT1, NT2 and NT3, respectively. The basic physical and chemical properties, heavy metals and enzyme activities in soil, biomass of soybean plants and bioconcentration of heavy metals were measured and analyzed.

Result The Nemero pollution index was calculated to evaluate the soil pollution situation of farmland around tailings, using the risk screening value of the national agricultural land soil pollution risk control standard as the evaluation standard. The soil pollution at NT0 adjacent to tailings was the most serious. The single pollution indices of copper, zinc, lead, nickel and chromium were 4.37, 1.19, 0.64, 0.24 and 0.13, respectively. And the comprehensive pollution index was 3.23, reaching the severe pollution level. The area within 1 km around the tailings was polluted by heavy metal, and the area within 3 km was warned to be polluted. The urease activity of farmland soil around the tailings was most sensitive to the changes in heavy metal content of soil, which could indicate the pollution situation in the area. The growth of soybean plants around the tailings was negatively correlated with the copper and zinc content in the farmland soil. Soybean plants had a higher ability to accumulate and transport zinc in the soil than copper.

Conclusion The Laoyaling tailings lead to heavy metal pollution in the surrounding farmland soil and inhibit crop growth, with potential ecological risks. It urgently needs further restoration and management.