Mercury distribution in the soil–plant–air system at the Wanshan mercury mining district in Guizhou, Southwest China

Abstract

The level of mercury bioaccumulation in wild plants; the distribution of bioavailable Hg, elemental Hg, and total Hg in soil; and the concentration of total gaseous Hg (TGM) in ambient air was studied at three different mining sites (SiKeng [SK], WuKeng [WK], and GouXi [GX]) in the Wanshan mercury mining district of China. Results of the present study showed that the distribution of soil total Hg, elemental Hg, bioavailable Hg, and TGM varies across the three mining sites. Higher soil total Hg (29.4-1,972.3 mg/kg) and elemental Hg (19.03-443.8 mg/kg) concentrations were recorded for plots SK and WK than for plot GX. Bioavailable Hg was lower at plot SK and GX (SK, 3-12 ng/g; GX, 9-14 ng/g) than at plot WK (11-1,063 ng/g), although the TGM concentration in the ambient air was significantly higher for plot GX (52,723 ng/m(3) ) relative to WK (106 ng/m(3) ) and SK (43 ng/m(3)). Mercury in sampled herbage was elevated and ranged from 0.8 to 4.75 mg/kg (SK), from 2.17 to 34.38 mg/kg (WK), and from 47.45 to 136.5 mg/kg (GX). Many of the sampled plants are used as fodder or for medicinal purposes. High shoot Hg concentrations may therefore pose an unacceptable human health risk. Statistical analysis of the recorded data showed that the Hg concentration in plant shoots was positively correlated with TGM and that the Hg concentration in roots was positively correlated with the bioavailable Hg concentration in the soil. The bioaccumulation factor (BAF) in the present study was defined with reference to the concentration of bioavailable Hg in the soil (Hg([root]) /Hg([bioavail])). Three plant species, Macleaya cordata L., Achillea millefolium L., and Pteris vittata L., showed enhanced accumulation of Hg and therefore may have potential for use in the phytoremediation of soils of the Wanshan mining area.

Biogenesis of Mercury–Sulfur Nanoparticles in Plant Leaves from Atmospheric Gaseous Mercury

“…These concentrations are well within levels reported previously in the two mining districts. 8,43 Ore-roasting and soil re-emission of previously deposited mercury are the main local source of Hg 0 g. 8,58 Ground-to-air fluxes are extremely variable. Spatial and temporal influences, such as proximity and Hg concentration at the point source (mine, soil, roasting site) and ore processing activity, and variation in Hg response to environmental variables and processes, such as photoreduction at the soil surface, can adequately account for the mean variations in measured Hg 0 g from site to site.…”

“…These concentrations are well within levels reported previously in the two mining districts. 8,43 Ore-roasting and soil re-emission of previously deposited mercury are the main local source of Hg g 0 . 8,58 Ground-to-air fluxes are extremely variable.…”

Accumulation and translocation of 198Hg in four crop species

“…In addition, the tendency of stem-to-leaf transfer for corn is relatively stronger among the 4 crops. Different levels of Hg accumulation in plant root have been reported for tomato, cabbage, clover, sugar beet, pea, wheat and rape when treated with soil and solution having different Hg concentrations [41][42][43]. The observed uptake differences were likely caused by the specific growth characteristics of each crop plant.…”

Combined toxicity of amorphous silica nanoparticles and methylmercury to human lung epithelial cells

“…The power plants, mining and metallurgical industry also release mercury to the ambient atmosphere, increasing the occupational exposure risk (Loredo et al, 2007;Gonzalez-Carrasco et al, 2011;Wang et al, 2011). Mercury in the air is easily taken up through the lungs, and about 74% of inhaled mercury is retained in human body (Syversen and Kaur, 2012).…”