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1.
This research aims to establish the risks of hurnan exposure to modeling approach. The study site was located on the River Nura 1990s, an acetaldehyde production plant located in the industrial high environmental mercury levels, based on a quantitative risk in central Kazakhstan. From the 1950s until its closure in the mid city of Temirtau released mercury-containing wastewater into the river. River sediments are highly contaminated with mercury up to a distance of 25 km and beyond. In addition, a local power station released an estimated 6 million tonnes of fly-ash into the water and the mercury has become quite tightly associated with the ash deposits. River water, fish and agricultural land in the floodplain are also contaminated with mercury, yet the risks posed to the local population have not been evaluated to date. In June and July 2005, we took samples of soil, interior and exterior dust, drinking water, and food from individual households, communal areas and markets. Additionally, water and sediment samples and fish were taken from the river. Interviews were conducted with householders to establish their age and body weight, general living conditions and sources of irrigation and drinking water. A food frequency questionnaire （FFQ） was designed to investigate the frequencies of consumption of several common regional food items, including fish from the fiver and/or local market. Human hair samples were also collected to estimate the mercury bioburden and to enable the validity of the modeling approach to be established. The paper expands on the main pathways of contamination and looks at linkages between exposure pathways and mercury concentrations found in human hair. Uncertainties inherent in risk analysis as well as their influence on the relative importance of different exposure routes are also discussed.  相似文献   

2.
《中国地球化学学报》2006,25(B08):236-236
It is still disputed in the scientific community whether it is possible to trace a direct link or even proportionality between mercury （Hg） anthropogenic loadings to lake ecosystems and resulting methylmercury （MeHg） levels found in fish tissues. We present here the exemplary case of the Baihua Reservoir, located on the Maotiahoe River, near Guiyang （Guizhou, China）. Baihua was impacted for many years by Hg-contaminated effluents from industrial source. While sedimentary profiles exhibit extreme enrichment in sedimentary Hg burden, fish species harvested from the reservoir still present low Hg levels. Thus we propose here that in the case of Hg, loading does not tell it all and one must take it into account the net methylation capacity of lake ecosystems and its ability to efficiently bioaccumulate MeHg along the trophic web.  相似文献   

3.
Objectives： To assess the exposure to elemental mercury （Hg0） vapor and methylmercury （MeHg） among mercury mine workers in an area of Guizhou Province, China. Methods： Urine total mercury （THg） and hair THg and MeHg were measured in 26 mercury miners and smelters （i.e., exposed group）, and 52 control subjects （unexposed group）. Results： The mine workers showed high geometric mean THg concentrations in urine （258 ng/mL, 226 μg/g creatinine） and hair （20.0 μg/g）. The urine Hg level of smelters, in particular, was extremely high （338 μg/g creatinine in urine）. The highest urine THg reached 4580 μg/g creatinine. THg concentrations in urine and hair showed a significant correlation in the exposed group （r=0.62）, indicating the adhesion of HgO vapor to hair. However, no such significant correlation was found in the control group.  相似文献   

4.
The concentrations of total mercury and methylmercury in sediments were determined at the dam of the Wujiangdu Reservoir in different seasons. Total mercury (HgT) levels in the whole sediment profile were 254.2±47.0 ng/g in winter, 254.2±31.6 ng/g in spring, and 256.7±60.8 ng/g in summer, without significant variations in different seasons or at different depths. In contrast, the methylmercury (MeHg) compounds were most abundant at the sediment-water interface and decreased progressively with depth. MeHg contents of the sediments during different seasons are highly dependent on microbial activity, and seem to be higher when Hg (II)-methylating microorganisms are active. Thus, MeHg levels tend to rise in the loci where nutrient supplies and biological productivity are favorable. The percentage of HgT that is present as MeHg in the sediments increased gradually from December 2003 to April 2004 and to July 2004.  相似文献   

5.
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.  相似文献   

6.
《中国地球化学学报》2006,25(B08):242-243
In direct continuation with the acquired knowledge of ecosystem approach for the presence of mercury in the Amazon, we have launched in 2001 the NSERC-supported pan-Canadian COMERN project. This Collaborative Mercury Research Network addresses the urgent need for the development of a framework enabling researchers, political stakeholders, and communities concerned by the mercury question to evolve towards an interdisciplinary association capable of synergistically combining our knowledge on Hg into an original synthesis. We are presenting a simple integrated indicator representative of the specific susceptibility of an ecosystem to Hg bioaccumulation and subsequent transfer to humans. This indicator includes three concepts： （1） the sensitivity to bioaccumulation, induced and influenced by factors such as the Hg loading, the different transport and methylation processes, and human activities; （2） the vulnerability of the populations exposed to Hg through consumption of local and market fish; and （3） the adaptability of the ecosystem and the people living into it, an evaluation of its resilience, or its capacity to recover and/or to cope with the contamination, taking into account the social and political resources within the communities impacted.  相似文献   

7.
Mercury is an important pollutant in lakes. Methylmercury （MeHg）, the most toxic mercury species, which can be formed from inorganic mercury in lakes, can be bioaccumulated into high concentration in food chain and result in a potential threat to human beings. Sediments play an important role for the Hg biogeochemistry in the aquatic systems： Mercury methylation has been shown to be fastest in the surfacial sediments, where the microbial activity is highest. The formation of MeHg in lakes suggests that sediments and/or near-shore wetlands can be the sources of MeHg in aquatic environments. The Baihua Reservoir, located in the suburb of Guiyang, was impounded in 1966. From the 1970s to the 1990s, Guizhou Organic Chemical Plant which used inorganic mercury as catalyst to produce acetic acid, was responsible for the discharge of waste water with high mercury content.  相似文献   

8.
In this study, we applied synchrotron radiation X-ray fluorescence technique （SR-XRF） to investigate the heavy metals including Hg and Pb in a few single strands of pinnule of the outermost wing feather of snow petrel （Pagodroma Nivea） collected in the Antarctic. The microscopic distributions of Hg and Pb along with the strand of pinnule show significant variation and the types of distribution are different for pinules, suggesting that external contamination may have an important impact on the levels of Hg and Pb, rather than reflecting levels in the blood during feather formation. This should be taken into account in future monitoring studies. The sources of Hg and Pb detected in the feather were also discussed. Using feathers of snow petrel to investigate the springtime mercury depletion events （MDEs） in the Antarctic were proposed.  相似文献   

9.
The cryosphere is one of the climate system component which plays an important role in the global biogeochemical mercury cycling. Anthropogenic mercury has been transported to remote cold and high regions worldwide through atmospheric circulation,and then transformed into methylmercury in the cryosphere. As one of the highly toxic environmental pollutants,methylmercury can be greatly bioaccumulated and biomagnified through the food web,which potentially poses threats to human and wildlife as well as the global cryospheric en⁃ vironments. In order to gain a full picture of research progress on methylmercury in the cryosphere,our study comprehensively summarized the concentration levels and analytical methods of methylmercury,and biogeo⁃ chemical processes such as the migration,transformation and fate of methylmercury in various cryospheric envi⁃ ronments including glacier,permafrost,snow ice and sea ice. We particularly made the literature review of mi⁃ crobial mercury methylation and evaluated the risk of methylmercury exposure to human and wildlife in the cryo⁃ sphere. Meanwhile,we focus on distribution,behavior,and environmental effects of methylmercury in the cryosphere against the backdrop of climate change,which is essential for assessing the exposure risk of methyl⁃ mercury to humans and wildlife. Perspectives of methylmercury researches in the cryosphere have also been highlighted in this review,though there is existing a knowledge gap of biogeochemical methylmercury cycling in the low temperature environments which merits further study. © 2023 The Author(s).  相似文献   

10.
The River Nura in central Kazakhstan has been heavily contaminated by mercury （Hg） from an acetaldehyde plant located in the industrial city of Temirtau. The plant released Hg-containing wastewater into the river from the 1950s until the mid 1990s and strongly contaminated the bed sediments up to 25 km downstream. In addition, a local power station released an estimated 6 million tonnes of fly-ash into the water which has adsorbed much of the Hg and has become mixed with the natural sediments. River water,fish and agricultural land in the floodplain are also contaminated by Hg. Humans are exposed to Hg primarily via the consumption of contaminated fish from the river. A survey was undertaken in June/July 2005 to investigate Hg concentrations in river water, drinking water, sediments and fish. To estimate the risk posed to the local population, approximately 300 hair samples were collected from people living in villages near the most contaminated section of the river, at a distance of between 5 and 30 km downstream of the acetaldehyde plant, and their dietary habits were recorded. Mercury concentrations in river water ranged from 2-3 ng/L upstream of the source of the pollution to 348 ng/L downstream of the factory outfall pipe. Some drinking water wells close to the river were contaminated, but deeper wells had Hg concentrations below the detection limit.  相似文献   

11.
In natural waters inorganic mercury （Hg） and methylmercury （MeHg） are complexed with a variety of inorganic and organic ligands, such as OH^-, Cl^-, sulfide, thiols, and dissolved organic matter （DOM）. The bioavailability and toxicity of Hg and MeHg are related to their speciation, instead of their total concentrations. Among these species, Hg-DOM and MeHg-DOM complexes are the least known, due to the complexity and site-specificity of DOM in natural waters. Here we report the complexation between DOM and Hg or MeHg using fluorescence spectroscopy. The Suwannee River fulvic acid, peat humic acid, amino acid typotophan, and natural organic matter from the Suwannee River, Nordic River, and Delta Marsh were studied at their respective excitation/emission maxima,  相似文献   

12.
Health risk from various particulates of dust has been of public health concern for many years and scientific observations on dust have been going on for the last 200 years. Diseases resulting from exposure to dust are generally known as pneumoconiosis and have been primarily associated with occupational exposure to silica dust. Silica, which induces silicosis, has been recognized as far back as the Hippocratic times. The aim of the research is to try to assess the nature and scale of health risks from environmental exposure to silica on a global scale, with particular emphasis on non-occupational silicosis （pneumoconiosis）. Thorough literature reviews included studies and literature from non-occupational and occupational silicosis studies along with papers from Geology and Medicine. Non-published studies and local knowledge from Ladakh were used in pertinent of the review. The commonest form of silica （SiO2） is quartz. Other particulates in the atmosphere and finer particles 〈10 when inhaled with oxygen endanger human health; silica is the most threatening for non-occupational silicosis because of its high fibrogenicity. Aerosol minerals can often travel from continent to continent creating a health risk not just in the area of dust source, but also to secluded humans. When emitted into the air environmental exposure to （silica） quartz can occur as component of particulates emissions produced by natural-industrial-agricultural activities. Human exposure to environmental （silica） quartz can be summarized into direct and indirect pathways. Health risk from exposure to silica （quartz） has been widely studied in occupational settings; however there is a scarcity of studies on environmental/non-occupational exposure. Review of epidemiological studies on environment/non-occupational silicosis showed that all the studies lack a good control group and represent a small sample size. Many of these studies are case reports with retrospective histopathology, focusing only on the prevalence and lacking robust exposure measurement. Non-occupational/environmental silicosis is a global public health concem and the areas of dust source could be modified with climate changes. Literature is very scarce in relation to health risks from environmental dust （silica/quartz）, nevertheless the review of occupational studies links silica exposure to numerous diseases in humans.  相似文献   

13.
In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations of lake water in the Aha Reservoir were greatly elevated as compared to those of the Hongfeng and Baihua reservoirs, which was correlated with its distinctly high SRB abundance, SO42-, and S2- concentrations. Among the three reservoirs, however, the highest MeHg was observed in in the top several centimenters of pore water profile in the Hongfeng Reservoir where the lowest S2- in pore water occurred. The distributions of MeHg in lake water and pore water showed the highest methylation potential occurred at water-sediment surface for the Aha Reservoir and the in the top several centimenters of sediments for the Hongfeng Reservoir. It is guessed that the highest mercury methylation only occurs at the sites with certain sulfide concentrations.  相似文献   

14.
Western Hunan Province is one of the most typical assembling areas of cryogenic metallic deposit in China, as well as a main ore-forming zone for some heavy metals. In the region, Hg and Pb pollution was caused by abnormally high concentrations of Hg, Pb in the natural environment and Hg, Pb exploiting/smelting and other human activities, which make the damage to human health more complicated. Generally, heavy metal pollutants in soil are often long-lasting and consequent, with their emission and/or transport into the environment, resulting in growing hazards to human health posed by elevated heavy metal concentrations in air, water, and food. Therefore, monitoring and understanding their behaviors in soil environment is the most important and urgent task. In this paper, the environmental behaviors and pollution characteristics of soil polluted by Hg and Pb in typical Hg and Pb mining areas in western Hunan were studied. Main results are presented as follows： （1） Western Hunan Province is a high regional geochemical abnormal region on Hg and Pb. The concentrations of Hg and Pb in soils in mercury mining areas were 1 315 and 3. l times higher than the average background of soils in China, respectively. While those in soils in lead mining areas are 14.1 and 6.1 times higher. By using the index of geoaccumulation （Igeo）, it was found that either mercury mining area or lead mining area in western Hunan Province has been polluted by the two elements, the majority of soils in mercury mining areas are seriously polluted by Hg, moderately or light polluted by Pb, while the majority of soils in lead mining areas are moderately or moderately-highly polluted by Pb and moderately-highly polluted by Hg. （2） By the BCR extraction procedures, both Hg and Pb in soils are dominated by residual form, followed by organic-sulfide form. Fe-Mn oxides and acid-exchangeable form are rather low. The total concentrations and each species of Hg and Pb in soils show positive correlations with the concentrations of sands, and negative ones with the concentrations of clays in soils.  相似文献   

15.
Small-scale mercury smelting activities with indigenous method are always extensive in the Wuchuan area, northeastern Guizhou Province, China. Because of the simple processes without any environmental protection, a large amount of mercury vapor released to the ambient air during the processing of cinnabar roasting. So the health of the workers may be negatively affected through inhalation of the mercury-polluted air. Mercury, creatinine and β2-MG contents in urine among the workers in the study areas and the residents in the control site （Changshun County） were determined to discuss the health impact of mercury vapor exposure to the workers in the study areas. Health examinations also were carded out to identify clinical symptoms of mercury poisoning for the smelting workers. Results indicated that the geometric mean value of urinary mercury for the smelting workers was g/g Cr μg/g Cr （N=22）, significantly higher than 1.24 μg/g （N=54） for residents in the control site. β2-MG as a renal biomarker can be used to study human nephrotoxicity at an early stage and it is most useful to define effects for assessing re-absorption function to indicate tubular injury. The results showed a serious adverse effect on renal system for the smelting workers due to mercury exposure. Several workers have already manifested some clinical symptoms of lightly chronic mercury poisoning and the symptoms include finger and eyelid lightly tremor, gingivitis and blue mercury line in mouth. The study illuminated that the workers in gaged in indigenous mercury smelting in the Wuchuan area were seriously exposed to mercury vapor,  相似文献   

16.
The Peoples＇ Republic of China produces and consumes the largest quantity of coal in the world; about 2.19 billion tons of coal were produced in 2005. It is estimated that coal consumption will reach 7 billion tons by 2020. Although the nationwide percentage of electrical production from coal is falling due to increased coal-fired power generation efficiency and alternative sources, China will bum more coal than any other country for the foreseeable future. China also is estimated to be the largest producer of Hg emissions （Dastoor and Larocque, 2004, Atmos. Envirn. 38：147-161）. A recent comprehensive study of anthropogenic Hg emissions in China （Streets et al., 2005, Atmos. Envirn. 39：7789-7806） produced a figure of 536 tons of Hg for the year 1999 with coal combustion （all types） accounting for 38% of the total. Atmospheric Hg emission is an international problem as the upper atmosphere provides effective global transport of mercury. Although the estimates vary, China produces about three times more Hg/t of coal burnt than the USA because of the lack of modem technology for pollution control and limited use of cleaned coal. Knowledge of the mercury content, mode of occurrence, and regional distribution in Chinese coal is vital in order to assess the global atmospheric contribution from Chinese coal combustion.  相似文献   

17.
The Hongfeng Reservoir was built in 1960 and is an alkaline, hyper-eutrophic and seasonal anoxic reservoir due to the contamination from domestic and industrial wastewaters. The water samples at deferent depths from two sampling sites were collected from November 2003 to September 2004 using metal clean protocols. Total Hg （THg）, reactive Hg （RHg）, dissolved total Hg （DHg）, dissolved gaseous mercury （DGM） were measured by gold trap pre-concentration and CVAFS detection. Methyl mercury was measured by distillation followed by aqueous phase ethylation, precollection on a Tenax, isothermal gas chromatography and cold vapor atomic fluorescence detection. There was no discernible seasonal trend （about 8 ng/L） in THg concentration based on the average information developed during the four cruises except for high concentrations at bottom and water-sediment interface in May and September 2004. On the other hand, particulate mercury （PHg） and methyl mercury have discernible seasonal variability. Proportion of PHg increased from 29% in February 2004 to 50% in May 2004. In November 2003, February and May 2004 methyl mercury concentrations were relative low and increased with depth （from 0.13 to 0.40 ng/L）. In September 2004, methyl mercury concentrations increased from 0.14 ng/L in the epilimnion to 0.99 ng/L in the hypolimnion. DGM concentrations varied from 0.024 to 0.11 ng/L and decreased with depth.  相似文献   

18.
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.  相似文献   

19.
Meishan Section D in Changxing County, Zhejiang Province, China has been selected as the global stratotype of the Permian-Triassic boundary and various studies hav been done at the boundary but the gas chromatographic-mass spectrographic analysis of alkane biomarkers has not been investigated. This paper presents of results of a study of the biomarkers analyzed in a series of samples across the permian-Triassic boundary at both Meishan Section A and Section D. The results show that the overall concentration of alkane biomarkers in the Permian-Triassic boundary strata is high in Bed 26 while it is low in Bed 27. A variety of biomarker parameters demonstrate that the main sources of organic matter in the sediment are algae and bacteria and that the depositional enviroment varied from weakly oxidizing to reducing during the studied interval.  相似文献   

20.
Mineral and organic matter either soluble or suspended are transported by the rivers and when deposited in the bed of the river or in the water reservoir, sediments are formed, whose chemical composition may serve as a fingerprint of the history of the ecosystem. The results of the studies of sediments in water systems （river catchments, reservoirs） can be used not only for the evaluation of the current state of the ecosystem but also to prevent any dangerous environmental changes. Bottom sediments can in many ways accumulate both suspended and soluble components. The process is influenced by several factors like pH, red-ox potential, oxygen content, interactions, etc. The complexity of those phenomena causes that in order to study the accumulation processes of compounds in sediments the application of various analytical techniques is required. The authors participate in two big projects on sediment studies. The AquaTerra Project is the EU funded project on understanding river-sediment-soil-groundwater interactions for support of management of river basins and catchment areas. Our group＇s studies are focused on mercury determination and its speciation in sediments and fish from the Ebro River in Spain. The Dobczyce Project is the national project funded by the Ministry of Education and sciences of Poland which is also a EU member country. The latter covers many aspects of accumulation and fate processes of chemical compounds in sediments of the reservoir which supplies 60% of drinking water to about one million population in the city of Krakow in Poland.  相似文献   

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