Spatiotemporal Analysis of Heavy Metal Pollution and Risks in Soils from a Shut-Down Electroplating Plant

Spatiotemporal analysis of heavy metal pollution and risks in soils from a shut-down electroplating plant was carried out. Two batch samples were tested in December 2020 and August 2022, obtained from different sampling positions and depths. The results show that Cu, Pb, As, and Ni were the main pollutants, and their spatial distribution characteristics in December 2020 and August 2022 were similar. The pollution depth of Cu, Pb, As, and Ni was mainly concentrated within 1.0 m from the ground. In the horizontal direction, the four kinds of pollutants had some relatively concentrated pollution areas and many dispersed pollution points. In December 2020, Cu contamination was heavy, and the comprehensive ecological risk was slight. In August 2022, Cu contamination was heavy, Pb contamination was moderate, and the comprehensive ecological risk was moderate as well. Both As and Ni posed carcinogenic risks in both samples. Cu, Pb, As, and Ni migrated very slowly under the action of rainfall infiltration. Soil pollution was primarily attributed to wastewater discharge, while dispersed pollution sites were mainly caused by the landfilling of production waste. The research findings hold significant implications for heavy metal pollution control and risk prevention in the soil of electroplating enterprises.