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991.
The correlation between specific activities of some natural radionuclides (238U, 226Ra, 232Th, 40K) measured in sediment taken from river bottom was studied. The sediment was taken from the Serbian part of the Danube River. Good correlation between some of the isotopes is observed, so that their specific activity ratios are spread over a lower range than specific activities themselves. This suggests that evaluation of specific activity ratios of some natural radionuclides could be a more sensitive method for the determination of increased levels of some of them than the straightforward analysis of specific activities. 相似文献
992.
Pan Wu Changyuan Tang Congqiang Liu Lijun Zhu TingQuan Pei Lijuan Feng 《Environmental Geology》2009,57(7):1457-1467
The chemical characteristics, formation and natural attenuation of pollutants in the coal acid mine drainage (AMD) at Xingren
coalfield, Southwest China, are discussed in this paper based on the results of a geochemical investigation as well as geological
and hydrogeological background information. The chemical composition of the AMD is controlled by the dissolution of sulfide
minerals in the coal seam, the initial composition of the groundwater and the water–rock interaction. The AMD is characterized
by high sulfate concentrations, high levels of dissolved metals (Fe, Al, Mn, etc.) and low pH values. Ca2+ and SO4
2− are the dominant cation and anion in the AMD, respectively, while Ca2+ and HCO3
− are present at significant levels in background water and surface water after the drainage leaves the mine site. The pH and
alkalinity increase asymptotically with the distance along the flow path, while concentrations of sulfate, ferrous iron, aluminum
and manganese are typically controlled by the deposition of secondary minerals. Low concentrations of As and other pollutants
in the surface waters of the Xingren coalfield could be due to relatively low quantities being released from coal seams, to
adsorption and coprecipitation on secondary minerals in stream sediments, and to dilution by unpolluted surface recharge.
Although As is not the most serious water quality problem in the Xingren region at present, it is still a potential environmental
problem.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
993.
Marleen Coetsiers Petra Blaser Kristine Martens Kristine Walraevens 《Environmental Geology》2009,57(5):1155-1168
Aquifers from the same typology can have strongly different groundwater chemistry. Deducing the groundwater quality of less
well-characterized aquifers from well-documented aquifers belonging to the same typology should be done with great reserve,
and can only be considered as a preliminary approach. In the EU’s 6th FP BRIDGE project “Background cRiteria for the IDentification
of Groundwater thrEsholds”, a methodology for the derivation of threshold values (TV) for groundwater bodies is proposed.
This methodology is tested on four aquifers in Flanders of the sand and gravel typology. The methodology works well for all
but the Ledo-Paniselian aquifer, where the subdivision into a fresh and saline part is disproved, as a gradual natural transition
from fresh to saline conditions in the aquifer is observed. The 90 percentile is proposed as natural background level (NBL)
for the unconfined Pleistocene deposits, ascribing the outliers to possible influence of pollution. For the Tertiary aquifers,
high values for different parameters have a natural origin and the 97.7 percentile is preferred as NBL. The methodology leads
to high TVs for parameters presenting low NBL, when compared to the standard used as a reference. This would allow for substantial
anthropogenic inputs of these parameters. 相似文献
994.
Theodore D. Kanellopoulos Michael O. Angelidis Dimitrios Georgopoulos Aristomenis P. Karageorgis 《Environmental Geology》2009,57(8):1729-1738
Evros River is the most important river flowing into the North Aegean Sea (eastern Mediterranean) in terms of freshwater discharge,
and the second largest one of Eastern Europe after the Danube River. Salinity and temperature measurements, together with
suspended particulate matter concentrations were obtained in various depths at 14 stations in the adjacent Alexandroupolis
Gulf during four seasons (June 1998, September 1998, February 1999 and March 2000) in order to investigate the particle dynamics
and distributions in the northern Aegean Sea. Analysis of the collected data, together with particle observations under the
scanning electron microscope and study of satellite images showed that, under certain circumstances driven by the hydrological
and wind regime of the area, the Evros River particulate matter, with the associated pollutants, can be transferred far away
from the estuary and implicitly comprise a hazardous factor for the environmental status of the northern Aegean Sea. This
fact, combined with the future construction of the Burgas-Alexandroupolis pipeline, may cause a negative impact on the studied
natural ecosystem. 相似文献
995.
甘肃省阳山超大型金矿床的有机地球化学特征研究 总被引:7,自引:4,他引:3
甘肃省文县阳山金矿是我国地质勘查储量最大的卡林-类卡林型金矿床,赋矿地层为泥盆系一套碳-硅-泥质地层.矿区发育了大量碳质千枚岩,富含有机碳.本文研究了矿石和围岩可溶有机质的生物标志物、有机质的来源和成熟度、干酪根的碳同位素等,论述了阳山金矿床的有机地球化学特征及有机质与成矿的关系,查明了参与成矿的有机质主要是菌藻类等低等生物.生物标志化合物参数和干酪根的H/C-O/C原子比值指示阳山金矿有机质成熟度较高,达到了无烟煤的演化阶段.在热演化的过程中,有机质裂解产生的CH_4和C-2H_6等进入成矿流体中,参与了成矿过程.阳山金矿赋矿地层中含有生物成因的草莓状黄铁矿,显示生物-有机质参与了地层的预富集作用.有机碳含量、有机质的类型和金的丰度之间相关性不明显,说明在阳山金矿的成矿过程中有机质对金的沉淀贡献不大,但是有机质可能参与了金的预富集和运移. 相似文献
996.
997.
对藏南发育完整的、厚度巨大的海相白垩纪地层中的暗色泥、页岩开展了有机质丰度研究。综合分析结果表明:该区泥、页岩中残余有机碳含量在0.05%~1.1%之间,平均值约为0.42%,其中下白垩统约为0.531%,上白垩统约为0.265%,有机碳平均含量变化特征与该区的古地理格局及海平面升降有关。氯仿沥青‘A’含量在0.0009%~0.0072%之间,平均含量约为0.0040%。有机碳与氯仿沥青‘A’最大值与最小值之比分别为22和8。有机碳与氯仿沥青‘A’这种弱负相关性与两者遭受剧烈的地表风化作用、强烈的紫外线照射和高程度有机质热演化后的损失量有关,后者远大于前者。白垩系残余有机碳含量大于0.6%的中等—好生油岩样10件,占样品总数的27%,下白垩统样品9件,占样品总数的24.3%,上白垩统样品1件,占样品总数的2.7%,表明来自北喜马拉雅地区东山组和康马—隆子地区甲不拉组的早白垩世泥、页岩为该区主要的有效生油岩。 相似文献
998.
天然气水合物在油气藏形成过程中的封盖作用——谈造山带中烃源岩对盆地区油气资源的贡献 总被引:2,自引:2,他引:0
在中国的造山带中普遍发育优质烃源岩,它们形成于海槽环境,而海槽环境也是形成天然气水合物的有利环境。水合物有良好的封盖作用,其下的油气受到封盖会向相邻的台地区运移,即油气从古海槽区(现今为造山带)向台地区(现今为盆地区)转移。因此造山带中的烃源岩对盆地区油气资源应有积极贡献。认为现今台西南海域的水合物与相邻油气藏具有同源性,这是水合物的封盖作用与油气藏形成之间具有密切联系的生动实例。四川盆地有限的烃源岩分布不能提供巨大的天然气储量,周边造山带可能也提供了相当的资源量。建议在四川盆地和秦岭造山带中系统采集气-液包裹体,以对比它们的亲缘关系,借以验证造山带中的烃源岩是否对盆地区的天然气成藏具有贡献。 相似文献
999.
河北南部地区石炭一二叠系煤层煤种丰富,峰峰、邯郸矿区煤层的宏观煤岩类型以半亮煤和半暗煤为主;显微煤岩类型为微镜煤、微镜惰煤及微暗煤;煤的结构以细、中宽条带状结构为主,在半亮煤和半暗煤中最多;有机显微组分以镜质组最高,一般可占50%~91%,惰质组占10%~35%,壳质组含量一般不超过5%,对煤层气来说,这是比较有利的烃源条件:区内大淑村矿2煤的矿物质含量最低,其煤的吸附能力较其它矿区高;主煤层镜质组最大反射率具有北高南低的分布规律,揭示了煤的生烃强度具有由南向北逐渐增高的趋势。该区煤层气源岩不仅影响煤的生烃能力,还影响着煤层对甲烷的吸附能力和煤层气的开采能力。 相似文献
1000.
某废弃煤矿竖井经倾倒有机废液,导致环境污染事件,造成巷道及采空区内地下水污染。本文结合场地实际情况,选取倾倒竖井(事故井)及周边区域为中试区域,采用“抽出处理+原位氧化循环”两阶段联合修复技术对污染场地开展中试研究。本文介绍了场地污染概况、地下水修复中试方案设计和实施,以及对修复效果进行评价。结果表明,中试处理后地下水中COD和二氯甲烷最高去除率分别为97.88%和99.74%。中试试验表明, “抽出处理+原位氧化循环”两阶段修复技术,对处理矿区内巷道及采空区等复杂地层结构下深层地下水中有机污染物具有较好的去除效果,可以结合现场实际情形对整个污染场区进行规模应用。 相似文献