Environmental mercury contamination of an artisanal zinc smelting area in Weining County, Guizhou, China

To investigate the extent of Hg contamination due to artisanal Zn smelting activities in Weining County, northwestern Guizhou, China, total Hg and methyl mercury (MeHg) concentrations in soil and surface water were determined. Samples of corn plants growing in the study area were also collected for total Hg analysis. A high geometric mean Hg emission factor of 75 g Hg t−1 Zn was estimated and significantly elevated total gaseous mercury (TGM) concentrations were found in the atmosphere adjacent to the Zn smelting sites, ranging from 30 to 3814 ng m−3. Total Hg and MeHg concentrations in topsoil samples ranged from 62 to 355 μg kg−1 and from 0.20 to 1.1 μg kg−1, respectively. Total Hg Concentrations in corn plant tissues increased in the order of grains < stalks < roots < leaves. This study revealed a significant Hg pollution to the local environment resulted from the artisanal Zn smelting activities.