Characteristics and Sources of Heavy Metals in Tailings-Derived Surface Material in the Largest Lithium Mine in China...

Lithium (Li) mining is one of the most critical strategic resources for sustainable development in the world. However, sources of heavy metals in Li mining have received limited attention. To explore the features and origins of heavy metals in Li mining tailings-derived surface material (TDSM), this study focused on the Yichun Li mine, China's largest one by reserves. The heavy metal enrichment was evaluated by single-factor enrichment index, and the source apportionment of heavy metals was performed using the PMF (Positive Matrix Factorization) model. Mean concentrations were As 12.95 ± 1.94, Pb 55.79 ± 8.93, Cu 58.35 ± 5.42, Cd 20.16 ± 0.48, Zn 109.81 ± 3.67, Ni 44.25 ± 3.26, Co 21.01 ± 1.25, Mn 809.60 ± 32.33, Cr 88.29 ± 4.27, and V 101.97 ± 5.41 mg kg^-1, respectively. Relative to the control samples, all heavy metals in TDSM exhibited varying degrees of enrichment. According to the single-factor enrichment index, the cadmium enrichment was the most severe (index = 130.55-215.55), while the enrichment levels of other heavy metals ranged from mild to moderate. Heavy metals were uniformly distributed within the 0-20 cm horizon, with no significant vertical variation. According to the PMF model, the potential sources of heavy metals were likely associated with mixed anthropogenic source, geogenic source associated with the weathering, and mining-related source, with estimated contribution rates of 25.7%, 43.8%, and 30.5% of the potential sources, respectively. These findings provide a theoretical basis for implementing source control measures for heavy metal enrichment in Li mining areas.