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The legacy of long-term mining activities in Wan-shan mercury (Hg) mining area (WMMA), Guizhou, China including a series of environmental issues related to Hg pollution. The spatial distribution of gaseous elemental mercury (Hg0) concentrations in ambient air were monitored using a mobile RA-915+ Zeeman Mercury Analyzer during daytime and night time in May 2010. The data imply that calcines and mine wastes piles located at Dashuixi and on-going artisanal Hg mining activities at Supeng were major sources of atmospheric mercury in WMMA. For a full year (May 2010 to May 2011), sampling of precipitation and through fall were conducted on a weekly basis at three sites (Shen-chong, Dashuixi, and Supeng) within WMMA. Hg in deposition was characterized by analysis of total Hg (THg) and dissolved Hg (DHg) concentrations. The corresponding data exhibit a high degree of variability, both temporarily and spatially. The volume-weighted mean THg concentrations in precipitation and through fall samples were 502.6 ng l-1 and 977.8 ng ll-1 at Shenchong, 814.1 ng ll-1 and 3392.1 ng ll-1 at Dashuixi, 7490.1 ng ll-1 and 9641.5 ng ll-1 at Supeng, respectively. THg was enhanced in through fall compared to wet deposition samples by up to a factor of 7. The annual wet Hg deposition fluxes were 29.1, 68.8 and 593.1 µgml-2 yrl-1 at Shenchong, Dashuixi and Supeng, respectively, while the annual dry Hg deposition fluxes were estimated to be 378.9, 2613.6 and 6178 µgml-2 yrl-1 at these sites, respectively. Dry deposition played a dominant role in total atmospheric Hg deposition in WMMA since the dry deposition fluxes were 10.4-37.9 times higher than the wet deposition fluxes during the whole sample period. Our data showed that air deposition was still an important pathway of Hg contamination to the local environment in WMMA. [ABSTRACT FROM AUTHOR]

The article discusses the study which examines the distribution of mercury (Hg) and the characteristics of its methylation in Wujiangdu (WJD) and Yinzidu (YZD) reservoirs in Guizhou province, China. It indicates that increased methylmercury concentrations in water samples from groundwater and surface water sediment interface have demonstrated an active net Hg methylation in WJD but not in YZD. The study implies that high primary productivity ensued from cage aquaculture activities in WJD can significantly control Hg methylation in the reservoir while increasing the MeHg concentrations in the Wujiang River basin in China.