Source apportionment and quantitative risk assessment of heavy metals at an abandoned zinc smelting site based on GIS and PMF models

The abandoned smelters have caused serious hazards to the surrounding environment and residents. Taking an abandoned zinc smelter in southern China as an example, a total of 245 soil samples were collected to study spatial heterogeneity, source apportionment, and source-derived risk assessment of heavy metal(loid)s (HMs) in the region. The results showed that the mean values of all HMs concentrations were higher than the local background values, with Zn, Cd, Pb, and As contamination being the most serious and their plume penetrating to the bottom layer. Four sources were identified by principal component analysis and positive matrix factorization, with their contributions to the HMs contents ranked as: surface runoff (F2, 63.2%) > surface solid waste (F1, 22.2%) > atmospheric deposition (F3, 8.5%) > parent material (F4, 6.1%). Among these, F1 was a determinant source of human health risk with a contribution rate of 60%. Therefore, F1 was considered to be the priority control factor, but it only accounted for 22.2% of HMs contents contribution. Hg dominated the ecological risk with a contribution of 91.1%. Pb (25.7%) and As (32.9%) accounted for the non-carcinogenic risk, while As (95%) dominated the carcinogenic effect. The spatial characteristics of human health risk values derived from F1 indicated that high-risk areas were mainly distributed in the casting finished products area, electrolysis area, leaching-concentration area, and fluidization roasting area. The findings highlight the significance of priority control factors (including HMs, pollution sources and functional areas) for consideration in the integrated management of this region, thus saving costs for effective soil remediation.

Automated summary

The abandoned smelters in southern China have led to serious environmental and health hazards. A study on an abandoned zinc smelter in the region found high concentrations of heavy metals in soil samples, with zinc, cadmium, lead, and arsenic contamination being the most severe. Surface runoff, surface solid waste, atmospheric deposition, and parent material were identified as the main sources of heavy metals. Surface solid waste was identified as the priority control factor for human health risk, but only accounted for a small percentage of the metal contents. Mercury posed the highest ecological risk, while lead and arsenic contributed to non-carcinogenic and carcinogenic risks respectively. The findings emphasize the need for prioritizing control factors in the integrated management and cost-effective soil remediation of the region.