Showing papers by "Xinbin Feng published in 2008"
TL;DR: It is concluded that the main human exposure to Me-Hg via food consumption is not restricted to fish, but in some cases in mining areas of China to frequent rice meals, which is likely to cause serious Hg pollution to the local environment.
Abstract: The toxicity of methylmercury (Me-Hg) has caused widespread public human concern as a result of several widely publicized disasters. Me-Hg is highly toxic, and the nervous system is its principal target tissue for humans. Although the general population is primarily exposed to Me-Hg through contaminated fish and marine mammals, in Hg mining areas a long history of mining activities can produce serious Hg pollution to the local environment In a study of 98 persons from the Wanshan Hg mining area, hair Me-Hg levels indicated Me-Hg exposure. Rice, the staple food of the local inhabitants also showed high total Hg (T-Hg) and Me-Hg levels. The geometric mean concentration of T-Hg and mean concentration of Me-Hg in rice samples collected from 3 villages in Wanshan Hg mining area were 36.2 (ranging from 4.9 to 214.7), and 8.5 (ranging from 1.9 to 27.6) microg/kg, respectively, which were significantly elevated compared to the rice samples collected from a reference area, where the mean T-Hg and Me-Hg concentrations were 7.0 (3.2-15.1) and 2.5 (0.8-4.3) microg/kg, respectively. Pork meat, vegetable, and drinking water samples collected in Wanshan Hg mining area contained highly elevated T-Hg, but very low levels of Me-Hg. The relationships between the estimated rice Me-Hg intake and hair Me-Hg levels (r = 0.65, p < 0.001) confirmed rice with high Me-Hg levels indeed was the main route of Me-Hg exposure for the local residents in the Wanshan Hg mining area. From our study, we can conclude that the main human exposure to Me-Hg via food consumption is not restricted to fish, but in some cases in mining areas of China to frequent rice meals.
396 citations
TL;DR: It is demonstrated that rice growing in Hg Hg-contaminated soil can accumulate methylmercury (MeHg) to a level to pose health threat to local inhabitants whose staple food is rice, contrary to the general point of view that fish and fish products are the main pathway of MeHg exposure to humans.
247 citations
TL;DR: It is reported that methylmercury in rice (Oryza sativa L.) grown at abandoned mercury mining areas contained levels >100 microg/kg in its edible portion and proved to be 10-100 times higher than other crop plants.
Abstract: Mercury is a global pollutant that can transform into methylmercury, a highly toxic and bioaccumulative organic form. Previous surveys have shown that fish is the main source of human methylmercury exposure, whereas most other food products have an average value below 20 microg/kg and primarily in the inorganic form. This paper reports that methylmercury in rice (Oryza sativa L.) grown at abandoned mercury mining areas contained levels >100 microg/kg in its edible portion and proved to be 10-100 times higher than other crop plants. The daily adult intake of methylmercury through rice consumption causes abnormally high methylmercury exposure to humans. The results demonstrate that rice is a methylmercury bioaccumulative plant and the main methylmercury source for human exposure in the areas studied.
230 citations
TL;DR: In this article, a set of automatic atmospheric mercury vapor analyzer (Tekran 2537A) at Moxi base station (102 degrees 07'E, 29 degrees 40'N, 1640m a.s.l.) of the Gongga alpine ecosystem observation and experiment station of Chinese academy of sciences (CAS) which belongs to the Chinese ecosystem research network (CERN).
120 citations
TL;DR: Wang et al. as discussed by the authors measured and wet deposition fluxes of total mercury (THg) and methyl mercury (MeHg) at 5 sites in Wujiang River Basin, Guizhou, China.
98 citations
TL;DR: Hair may be a useful tool for monitoring human exposure of Hg vapor in Hg-mining areas and the population in the study area was also at a potential risk of Me-Hg exposure via rice intake.
95 citations
TL;DR: The mercury distribution and speciation in the water column were investigated and showed that algae had a large capacity to bind mercury in late spring (e.g. in May), and it was shown that dissolved gaseous mercury (DGM) concentrations may also be affected by algae activities.
92 citations
TL;DR: Wang et al. as mentioned in this paper measured concentrations of total Hg (T-Hg) in mine waste, stream water, soil and moss samples collected from the Tongren area, Guizhou, China to identify potential Hg contamination to local environments, which has resulted from artisanal Hg mining.
80 citations
TL;DR: The average TPM and RGM concentrations in the study site were 30.7 and 6.2 pg m(-3), respectively, which are comparable to values observed in remote areas in Northern America and Europe, but much lower than those reported in some urban areas in China as mentioned in this paper.
73 citations
TL;DR: The smelting workers in Wuchuan were seriously exposed to mercury vapor through inhalation and the exposure route of Me-Hg may be through intake of polluted diet, according to this study.
66 citations
TL;DR: A significant Hg pollution to the local environment resulted from the artisanal Zn smelting activities, and total Hg concentration in corn plant tissues increased in the order of grains
TL;DR: In situ total gaseous mercury (TGM) concentrations and mercury exchange fluxes from 17 sampling sites of three representative landscapes (agriculture, grassland, and forest) were intensively measured in the eastern flank of Mount Gongga area, Sichuan province, southwestern China, from October 2005 to September 2006 as discussed by the authors.
Abstract: In situ total gaseous mercury (TGM) concentrations and mercury exchange fluxes from 17 sampling sites of three representative landscapes (agriculture, grassland, and forest) were intensively measured in the eastern flank of Mount Gongga area, Sichuan province, southwestern China, from October 2005 to September 2006. Average TGM concentrations in ambient air ranged from 1.60 to 5.10 ng m(-3) in warm season, while the values were highly elevated in cold season with the highest mean TGM concentration of 7.65 ng m(-3). Hg fluxes from agriculture and grassland sampling sites showed clearly seasonal distribution pattern with net depositions observed in cold season and net emissions observed in warm season. Mean Hg fluxes at agriculture and grassland field fell in the range from -4.1 to 132.0 ng m(-2) h(-1) and from -18.7 to 13.4 ng m(-2) h(-1), respectively, while mean Hg fluxes from forest sites varied from 0.5 to 9.3 ng m(-2) h(-1). Notable diurnal pattern of Hg fluxes were observed from all sampling sites, with the maximum Hg fluxes observed at midday and the minimum values observed during the nighttime. TGM concentrations in cold season significantly negatively correlated with Hg flux, suggesting that highly elevated TGM concentration could inhibit Hg emission even cause significant deposition. Vegetation acted as a great sink of air Hg in cold season, while in warm season, it could significantly inhibit Hg emission from surfaces.
TL;DR: The results suggested that sediments experienced serious contamination of Hg, and the contaminated sediment is an important Hg contamination source to the overlying water.
TL;DR: In this article, total gaseous mercury exchange fluxes between air and water surface were measured using a dynamic flux chamber (DFC) coupled with a gas analyzer at two sampling sites of Hongfeng reservoir in cloudy and rainy weather conditions.
Abstract: [1] Total gaseous mercury (TGM) exchange fluxes between air and water surface were measured using a dynamic flux chamber (DFC) coupled with a gaseous mercury analyzer at two sampling sites of Hongfeng reservoir in cloudy and rainy weather conditions. The concentrations of dissolved gaseous mercury (DGM) in water were also measured and indicated that DGM was supersaturated at most time during the sampling periods, which implied that the water body acted primarily as a source of mercury to the atmosphere. In general, TGM fluxes displayed a consistent diurnal pattern with peak fluxes at noon and minimum levels at early morning or night. However, this diurnal pattern was not clear when the weather was heavily cloudy and rainy with the maximum solar radiation of less than 140 W m−2. At this specific weather condition, a significantly positive correlation between TGM flux and relative humidity was observed. The behaviors of TGM flux over Hongfeng reservoir observed at cloudy weather conditions were some what different from those observed during mostly sunny weather conditions in Northern America and Europe. The empirical model developed based on the correlation between TGM flux and solar radiation during sunny days in Northern America was not applicable for estimation of TGM flux at cloudy and rainy weather conditions.
Journal Article•
TL;DR: Methyl mercury concentrations are highest in spring, without significant variations in other seasons, and the methyl mercury concentrations in solid phase and pore water are controlled by solid/water partition coefficient, as well as methyl mercury production.
Abstract: Spatial and temporal distributions of total and methyl mercury and controlling factors were investigated based on cold vapor atomic fluorescence detection. Total mercury levels in the whole sediments are (0.392 +/- 0.070) microg/g, without significant variations between different seasons, but generally increase toward the sediment-water interface. Total mercury levels are higher compared to data reported in other uncontaminated reservoirs and Wujiangdu Reservoir. This indicates there are mercury contaminations in Hongfeng Reservoir. Methyl mercury concentrations are highest in spring, without significant variations in other seasons. The peak values of methyl mercury typically appear in the upper 8 cm of the sediment profiles which are also the zones of sulfate-reducing bacteria activities. The seasonal variation and maximum peak value distributions of methyl mercury in sediment are mainly controlled by seasonally migration of oxic/anoxic boundary layer. Total mercury concentrations in the pore water and partition coefficients for THg in solid phase and water phase are mainly controlled by temperature or redox potential. Total mercury concentrations in the pore water have no relationship with total mercury concentrations in solid phase. However, the methyl mercury concentrations in the pore water have a strong relationship with those in solid phase (r = 0.70, p < 0.001). The methyl mercury concentrations in solid phase and pore water are controlled by solid/water partition coefficient, as well as methyl mercury production.
TL;DR: Wang et al. as mentioned in this paper collected water, pore water, sediment, and fish samples from the Hongfeng Reservoir in November 2003 and February 2004 in accordance with trace metal protocols.
Abstract: The water, pore water, sediment, and fish samples were collected from the Hongfeng Reservoir in November 2003 and February 2004 in accordance with trace metal protocols. The average concentrations of total mercury (THg), dissolved mercury (DHg), reactive mercury, dissolved gaseous mercury, total methylmercury, and dissolved methylmercury in the water columns were 8.00, 5.70, 0.63, 0.05, 0.16, and 0.07 ng/L, respectively. THg and DHg in the water columns, THg in pore water and THg in lake sediments of the Hongfeng Reservoir showed the level of mercury in the Hongfeng Reservoir was higher than in other natural waters in the world due to the loading of a lot of waste water with relatively high concentrations of mercury, whereas methylmercury concentrations in fish (wet weight) varied from 1.73–51.00 ng/g, much lower than in most remote lakes and reservoirs reported in northern Europe and North America. Methylmercury distributions in pore water and sediments showed methylation occurred mainly in the upper several centimeters of sediment cores in the Hongfeng Reservoir. The concentrations of dissolved organic carbon, total suspended particles, total Hg, and methylmercury were higher at Houwu than those at Daba in November 2003. It is suggested that other pollutants such as N and P from fishing farm and other waste water at Houwu, which resulted in deterioration of water quality, affected the concentrations and distributions of mercury species in the reservoir.
TL;DR: In this paper, the highly-time resolved atmospheric mercury concentrations have been measured at Moxi Base Station (102 degrees 72'E 29 degrees 92'N, 1640 in asl) from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A).
Abstract: Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local, regional and global studies of atmospheric long-range transport processes, and they could also provide valuable information about the impact of emission controls on the global budget of atmospheric mercury, their observance and an insight into the global mercury cycle. China is believed to be an increasing atmospheric mercury emission source. However, only a few measurements of mercury, to our knowledge, have been done in ambient air over China. The highly-time resolved atmospheric mercury concentrations have been measured at Moxi Base Station (102 degrees 72'E 29 degrees 92'N, 1640 in asl) of the Gongga Alpine Ecosystem Observation and Experiment Station of Chinese Academy of Sciences (CAS) from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A). Measurements were carried out with a time resolution 0 every 15 minutes. The overall average total gaseous mercury (TGM) covering the measurement periods was 4+/-1.38 ng.m(-3) (N=57310), which is higher than the global background level of approximately 1.5 similar to 2.0 ng.m(-3). The measurements in all seasons showed a similar diurnal change pattern with a high concentration during daytime relative to nighttime and maximum concentration near solar noon and minimum concentration immediately before sunrise. The presence of diurnal TGM peaks during spring and summer was found earlier than that during autumn and winter. When divided seasonally, it was found that the concentrations of TGM were highest in winter with 6.13 +/- 1.78 ng.m(-3) and lowest in summer with 3.17 +/- 0.67 ng.m(-3). There were no significant differences in TGM among wind sectors during each season. Whereas Hg generally exhibited significant correlations with the parameters, such as temperature, saturated vapor pressure, precipitation, ultraviolet radiation (LTV) and atmospheric pressure at the whole measurement stage, and the correlations varied seasonally. Our results suggest that the local or regional abundant geothermal activities, such as thermal spring, anthropogenic source processes and changes in meteorological conditions, regulate and affect Hg behavior in the study area.
TL;DR: Wang et al. as mentioned in this paper assessed the level of contamination of Hg in farmland soils along the irrigating channel downstream from Guizhou Organic Chemical Factory (GOCF), where metallic mercury is used as a catalyst to produce acetic acid.
Abstract: This study assesses the level of contamination of Hg in farmland soils along the irrigating channel downstream from Guizhou Organic Chemical Factory (GOCF), where metallic mercury is used as a catalyst to produce acetic acid. The total input of mercury into the environment, as announced by GOCF, is 140 t in the past 30 years (1971–2000). Sampling sites were chosen based on the distance from the source of pollution—the chemical factory. A total of 39 samples were collected from the study area and analyzed for total mercury concentrations and methyl mercury concentrations. The characteristics of vertical and horizontal distributions of total mercury and methyl mercury in the study area (farmland) are described in this paper. Much attention was paid to the transformation of inorganic Hg into organic mercury species in soils as well. The results showed that the farmland has been heavily contaminated by Hg. Land cultivation activity, land utilization style and distance from the pollution source could be the dominant factors controlling the distribution of THg and MeHg. It is observed that active transformation of inorganic Hg into organic mercury species (MeHg) usually takes place in paddy soils.
Journal Article•
TL;DR: Results show mercury concentrations are totally elevated in Changbai Mountain area and the regional source of mercury in the atmosphere seems to be anthropogenic Hg emissions mainly due to local biofuel use and coal combustion from industry and domestic uses.
Abstract: An intensive field campaign monitoring was conducted from August 2005 to July 2006 using the automatic atmospheric mercury analyzers for one year' s measurement of total gaseous mercury (TGM) in Changbai Mountain area. Results show the mean concentration of TGM is (3.22 +/- 1.78) ng x m(-3) and it presents seasonal variation as followings: winter > spring > autumn > summer. Given the background concentration of atmospheric mercury in the Northern Hemisphere, mercury concentrations are totally elevated in Changbai Mountain area. The regional source of mercury in the atmosphere seems to be anthropogenic Hg emissions mainly due to local biofuel use and coal combustion from industry and domestic uses. The potential mercury source may be regional mercury emissions from soil and the long distance transportation of mercury in the atmosphere.