Potentially toxic element source apportionment and risk assessment in agricultural soils around a large-scale Pb-Zn mine in Southwest China

Potentially toxic element (PTE) pollution from mining activities has raised global concerns because of its significant toxicity, bioaccumulation, and persistence. Therefore, the aim of the study was to establish a solid scientific foundation for precise pollution control, by accurately quantifying PTE pollution sources entering farmlands and assessing their potential ecological risk (PER). Typical PTEs (Cd, Ni, Pb, Cu, Zn, Cr, As, and Hg) were detected in farmlands surrounding a large-scale Pb-Zn mining area. Among the topsoil samples, 89.09 % (Cd), 62.72% (Pb), 49.09% (Zn), 45.45% (Hg), 24.55% (As), and 0.91% (Cu) of the samples exceeded their corresponding risk screening values. Source apportioning integrated three approaches: multivariate statistical analysis (MSA), PTE ratio correlation analysis, and positive matrix factorization (PMF). The results showed that 76.7 % of Ni, 76.5 % of Cr, and 54.6% of Cu were derived from natural sources; 87.6 % of Hg was derived from industrial activities; 89.2 % of Cd, 82 % of Zn, and 77.1 % of Pb originated from solid wastes; and agricultural activities accounted for 75.1 % of As and 23% of Cu. For further assessment, the PER model was used to quantify the risks of different sources, ranking them from highest to lowest as follows: solid wastes > industrial activities > natural sources > agricultural activities. Therefore, more measures must be taken to control solid waste pollution. Our findings can contribute to pollution source control, targeted soil remediation, and the establishment of effective environmental protection policies. These integrated methods can guide the source apportionment and risk assessment of PTEs.