Search

Abstract: Antimony (Sb) distribution and accumulation in plants in Xikuangshan Sb deposit area, the only one super-large Sb deposit in the world, Hunan, China were investigated. Results show that soils were severely polluted with the average Sb concentrations up to 5949.20mg kg−1. Sb widely occurred in 34 plants with various concentrations ranging from 3.92mg kg− 1 to 143.69mg kg−1, Equisetaceae family has the highest concentration (98.23mg kg−1) while Dryopteridacea family has the lowest one (6.43mg kg−1). H. ramosissima species of Equisetaceae family had the highest Sb average concentration of 98.23mg kg−1 and P. vittata species of Pteridaceae family showed advantage of accumulating Sb from the contaminated environment (Biological Accumulation Coefficient, BAC=0.08). Almost all species enriched Sb in their upground part such as shoot, leaf and flower (Biological Transfer Coefficient, BTC>1), which may attribute to the high acropetal coefficient and Sb transformation from the atmosphere to the plants. P. phaseoloides and D. indicum showed predominantly accumulation of Sb in the upground part with BTC of 6.65 and 5.47, respectively. From the low bioavailable fraction in soils and weak relationship between total soil concentrations in soils and plants, it seems that the Sb bioavailability was limited and varied with different soil sites as well as plant species. Those observations would be significant to the phytoaccumulation and phytoremediation of plants and ecological and environmental risk assessment in Sb contaminated areas. [ABSTRACT FROM AUTHOR]

Fluorine is one of the potential hazardous trace elements in coal. Fluorine may be released into atmosphere mostly during coal combustion process. When the coal is burning indoors without any controlling methods (chimney), the fluorine will pollute the room and is absorbed by food fired (dried) over stoves. Now many people have suffered from fluorosis due to coal burning indoors in Southwest China. In this paper, the concentration, distribution, mode of occurrences and impact factors of fluorine in Chinese coals are analyzed. The environmental impacts and typical features of fluorosis are studied. It is concluded that the value of fluorine in Chinese coals ranges from 20 to 300 mg/kg, and with average value of 122 mg/kg from 5,603 coal samples. It is higher than the average value of the world coals (80 mg/kg). In provincial coalfields of the SW China, the content of F is highest and many people have been affected due to coal combustion indoors. [ABSTRACT FROM AUTHOR]

The Huainan coalfield situated in the southern margin of North China Plate contains coal deposits of Carboniferous–Permian age. The 1 and 3 seams of the Early Permian Shanxi Formation and seams 4-1, 4-2, 5-1, 7-2 and 8 of the Late Early Permian Lower Shihezi Formation were analyzed for coal petrography, mineralogy and geochemical parameters. Collected data were designed to offer basic information on the assessment of coal quality and further to reveal possible factors controlling on coal quality. The shift of basin subsidence center from Huaibei coal-bearing basin to Huainan coal accumulation region caused the change of coal-forming environment (groundwater table, detrital matters and swamp style) which may further cause the differences in coal quality. The average vitrinite contents, ash yields and mineral matters are higher in the Lower Shihezi Formation coals than in the Shanxi Formation coals. The contents of vitrinite sharply decrease upward within coal seam 4, whereas the inertinite contents, ash yields and mineral matters show opposite trend which may be attributed to the relatively high-accommodation settings produce coals usually in the form of an upward high-to-low vitrinite succession. Two groups of elements are classified among coal seams. According to the vertical variation of elements contents among coal seams, most of elements in Group 1 are depleted in coal seam 4-2 except for Be, B, Sc, Fe, Mg, Ca, Li, Sn while almost all the elements in Group 2 are enriched in coal seam 4-2. [ABSTRACT FROM AUTHOR]

Pollutant emissions from coal fires have caused serious concerns in major coal-producing countries. Great efforts have been devoted to suppressing them in China, notably at the notorious Wuda Coalfield in Inner Mongolia. Recent surveys revealed that while fires in this coalfield have been nearly extinguished near the surface, they persist underground. However, the impacts of Hg volatilized from underground coal fires remain unclear. Here, we measured concentrations and isotope compositions of atmospheric Hg in both gaseous and particulate phases at an urban site near the Wuda Coalfield. The atmospheric Hg displayed strong seasonality in terms of both Hg concentrations (5-7-fold higher in fall than in winter) and isotope compositions. Combining characteristic isotope compositions of potential Hg sources and air mass trajectories, we conclude that underground coal fires were still emitting large amounts of Hg into the atmosphere that have been transported to the adjacent urban area in the prevailing downwind direction. The other local anthropogenic Hg emissions were only evident in the urban atmosphere when the arriving air masses did not pass directly through the coalfield. Our study demonstrates that atmospheric Hg isotope measurement is a useful tool for detecting concealed underground coal fires.

Environmental geochemistry of antimony (Sb) has gained much attention recently because of its potential toxicity. We have reviewed the distribution, modes of occurrence, geological processes and environmental effects of Sb in Chinese coals. Data of Sb in 1058 coal samples from China were compiled and the average Sb content in Chinese coals is estimated to be 2.27 microg/g. Average Sb content in coals from provinces, cities and autonomous regions may be divided into three groups. Group 1 has a low average Sb content of lower than 1 microg/g, Group 2 has a medium average Sb content of 1-3 microg/g, and Group 3 has a high average Sb content of >3 microg/g. Coals from Guizhou and Inner Mongolia are extremely enriched in Sb. The abundance of Sb in coals differs among coal-forming periods and coal ranks. Antimony occurs in several modes in coals. It may substitute for iron or sulfur in discrete pyrite grains or occurs as tiny dispersed sulfide particles in organic matter. During coal combustion Sb is partly released to the atmosphere and partly partitioned into solid residues. Antimony in the environment brings about definite harm to human health.

Toxic trace elements emitted during coal combustion are the main sources of air pollution. They are released into the atmosphere mainly in the forms of fine ash, smoke and flue, and thus adversely affect plant, animal and human health. Selenium is one of toxic and the most volatile in coal. Large amount of atmospheric emission of selenium, as well as selenium present and scrubber stockpiles in ash may create serious environmental problems. In the paper, on the basis of investigating the abundance and distribution of selenium in plant-rings during recent 20 years, the bioaccumulation of selenium is explained that selenium in plant, which were collected from the village of selenium-rich coal combustion, is much higher than that in plants collected away from the village of selenium-rich coal combustion. The main origins of selenium are selenium-rich coal combustion and high-selenium rock weathered. The selenium recycle by food chain and selenium will accumulate and redistribute in environments.