Thallium, arsenic, and mercury contamination of soil near the world's largest and longest- operating tungsten mine

Little is known about soil thallium contamination near tungsten (W) mines. This study investigated thallium, arsenic, and mercury contents and enrichment in agricultural soils near the world's largest and longestoperating W mine in China. Results show that the long-term W mining significantly elevated Tl from 0.77 to 1.61 mg·kg^-1 and As from 7.54 to 22.64 mg·kg^-1, with enrichment factors of 2.0 (1.4 to 3.7) and 2.9 (1.5 to 7.2), respectively. Hg contents were similar at the contaminated site (0.16 mg·kg^-1) and control site (0.19 mg·kg^-1), but were two to three times higher than the soil background content of Jianxi province. Thus, Hg contamination in the soil probably was mainly caused by coal and petrol burning instead of W mining.