Ecological and health risk assessments of heavy metal contamination in soils surrounding a coal power plant

Abstract

Coal combustion at power plants is a significant source of environmental pollution, with the deposition of heavy metals in soils leading to extensive ecosystem contamination and exacerbating the harmful impacts of human activities. This study presents a field investigation of heavy metal concentrations in soils around a coal-fired power plant, with monitoring sites located 1.7 to 15.2km from the plant. Data collection occurred in 2015, 2020, and 2024 across 11 monitoring sites. X-ray fluorescence analysis was used to assess heavy metal concentrations in soil. A life cycle assessment (LCA) with ReCiPe method was conducted to evaluate the impacts on both ecological and human health. The results revealed that the concentrations of Pb, Zn, Cu, Ni, Mn, Cd, and Cr exceeded threshold levels set by both the World Soil Average and the Regional Geochemical Background. The correlation analysis shows that organic matter and clay content play vital roles in reducing the mobility of heavy metals in soil through adsorption. Notably, strong correlations between Pb and Cd suggest a common origin from coal seam minerals. The LCA shows that freshwater ecotoxicity, marine ecotoxicity, terrestrial ecotoxicity, and human toxicity increased by over 30% compared to the World Soil Average pollutant levels. Nickel was identified as the primary contributor to marine and freshwater ecotoxicity, while manganese had the most significant impact on human toxicity. This study provides a better understanding of the long-term consequences of heavy metal accumulation in soils near coal-fired power plant. The data on anthropogenic impacts are crucial for developing effective strategies to mitigate environmental risks associated with pollution.