Pollution Characteristics, Source Apportionment, and Risk Assessment of Heavy Metals in Agricultural Soils Around Smelters in Jiyuan, China

This study proposes a systematic approach to characterize heavy metal (HM) contamination and conduct source-oriented risk assessment in agricultural soils surrounding a smelter in Henan Province. The pollution status was evaluated by determining local geochemical baseline concentrations (GBCs), with values for Cr, Ni, Zn, Cu, Cd, and Pb being 28.91, 14.75, 39.6, 18.30, 0.63, and 37.34 mg·kg−1, respectively. The pollution levels of individual metals followed: Cd > Pb > Cu > Zn, with an overall assessment indicating moderate contamination. Four sources were identified through Geographic Information System (GIS) spatial analysis and positive matrix factorization (PMF): smelting sources (31.1%), mixed livestock-agricultural sources (15.3%), natural sources (33.7%), and traffic sources (19.9%). Ecological and health risks were quantified using PMF-based risk assessment models. The ecological risk (ER) index was as high as 175.48, primarily driven by smelting sources (70.63%) and Cd. Noncarcinogenic risk (NCR) was mainly attributed to smelting sources (39%) and Pb, whereas carcinogenic risk (CR) was primarily contributed by natural sources (78%) and Ni. The probability of carcinogenic risk exceeding the acceptable threshold is 100%, potentially linked to the local cancer incidence rate. Therefore, regulating smelting activities and controlling low-concentration yet high-risk metals (Ni and Cd) are crucial for effective environmental management.