Spatial Distribution, Contamination Feature, and Health-Risk Assessment of Heavy Metals and Metalloids in Farmland Soil in the Hunan Province, China

Abstract

The objective of this study was to investigate the content characteristics of heavy metals, metalloids, and nutrients in farmland soil in the entire Hunan Province, China. In addition, the spatial distribution features, pollution risk, and probability health risk were further analyzed using a geographic information system, integrated pollution risk index, and Monte Carlo simulation. The results showed a significant Cd accumulation in the soils of Hunan Province. Total nitrogen and soil organic matter were at a higher nutrient level, whereas total phosphorus was relatively low. Areas with high Hg, Cd, As, and Pb levels mainly appeared in Chenzhou, Hengyang, and southern Zhuzhou, where nonferrous metal mining and smelting activities were frequent. High-nutrient areas were mainly located in Xiangtan, Lou Di, and the surrounding areas of Dongting Lake. The pollution risk assessment showed that Cd in soils was at a moderately pollution level, Hg was at a moderate to slight pollution level, and As, Cr, and Pb had the lowest pollution risk. The carcinogenic risk caused by accidental ingestion of Cr and As in soil was high, and farmers had a 75% probability of facing potential health threats. This study provides baseline and scientific data for formulating and implementing corresponding preventive measures and public policies.