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331.
Zhiguang Song Keith W. Jones Nebojsa Marinkovic Xian Ming Xiao Huan Feng Elli Tchouparova 《洁净——土壤、空气、水》2011,39(12):1041-1049
Dredging and remediation of contaminated Harbor sediments requires characterization of organic pollutants. In this paper, we apply a combination of Fourier transform IR attenuated total reflectance (FTIR‐ATR) and synchrotron FTIR techniques to the investigation of sediments and related materials from New York/New Jersey Harbor and other locations. The FTIR techniques give information on the functional groups of the compounds found in the sediments and make possible measurements with a spatial resolution of about 0.015 mm. Comparisons of natural organic materials namely, river and groundwater humic substances, recent marine and lacustrine sediments, and ancient sedimentary kerogen show that contaminated NY/NJ Harbor sediments display a strong and distinct absorption in their IR spectra at 2850–2950 cm?1 identified as a C? H stretching band, indicative of the presence of anthropogenic hydrocarbons. We suggest that the presence of this band could be used for rapid screening for the presence of contaminant organic compounds in sediments encountered in dredging operations and/or as an indicator for the efficacy of sediment decontamination technologies used for treatment of dredged material. 相似文献
332.
Daniele Botelho de Souza Karina Scurupa Machado Sandro Froehner Cristóvão Fernandes Scapulatempo Tobias Bleninger 《Chemie der Erde / Geochemistry》2011,71(2):171-176
The geochemical composition of lake bed sediments of a tropical reservoir in Brazil have been investigated. The C, N, P composition showed almost no variation between the different sampling points. All samples contained inorganic phosphorus (IP) ranging from 52 to 70%. The Redfield ratios show that the lake is without significant anthropogenic inputs. Most of the organic matter is composed by higher plants decomposition revealed in the total organic carbon (TOC):nitrogen (N) ratio ranging from 15.4 to 57.2. Also, TOC:organic phosphorus (OP) ranged from 265.3 to 933.6, suggesting that most of the organic matter has terrestrial origin from wood plants. The ratios suggest that most organic matter is influenced by the terrestrial characteristics of the watershed. Furthermore, the relative abundance of n-alkane homologues in the sediments was investigated. All samples have been analyzed for the n-alkanes C8 to C40. The sediments were dominated by n-alkanes C25–C38. It is concluded that n-alkane in sediments mainly come from terrestrial plants, however there is a contribution of submerged aquatic plants, especially in those sites in deeper areas of the lake. On the basis of Paq index the n-alkanes in sediments comes from terrestrial plants, however there is a contribution from emerged/floating plants.The investigated lake seems to be considered as meso to eutrophic. Because of the relatively high primary productivity in the lakes, there is a substantial organic-matter flux to the sediments, which rapidly becomes anoxic. According to the pristine/phytane ratio the sediments represent an anoxic environment with values found between 0.38 and 1.72. 相似文献
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334.
岩溶管道系统中污染物扩散及地下水自净能力研究——贵州某磷石膏堆场为例 总被引:1,自引:0,他引:1
以实验场水文地质勘查、室内外实验为基础,对磷石膏废液中TP(总磷)、F-(游离态氟化物)在岩溶管道系统中扩散和迁移的规律、岩溶管道地下水系统自我净化能力进行了研究。结果表明:污染物主要沿岩溶管道、裂隙的延伸方向扩散和迁移,而在垂直地下水径流方向不明显;TP、F-浓度在迁移的过程中的衰减主要与地下水系统中地下水的稀释有关... 相似文献
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337.
Geochemical characteristics and hydrocarbon generation modeling of the Jurassic source rocks in the Shoushan Basin, north Western Desert, Egypt 总被引:1,自引:0,他引:1
Mohamed Ragab ShalabyMohammed Hail Hakimi Wan Hasiah Abdullah 《Marine and Petroleum Geology》2011,28(9):1611-1624
The Shoushan Basin is an important hydrocarbon province in the Western Desert, Egypt, but the origin of the hydrocarbons is not fully understood. In this study, organic matter content, type and maturity of the Jurassic source rocks exposed in the Shoushan Basin have been evaluated and integrated with the results of basin modeling to improve our understanding of burial history and timing of hydrocarbon generation. The Jurassic source rock succession comprises the Ras Qattara and Khatatba Formations, which are composed mainly of shales and sandstones with coal seams. The TOC contents are high and reached a maximum up to 50%. The TOC values of the Ras Qattara Formation range from 2 to 54 wt.%, while Khatatba Formation has TOC values in the range 1-47 wt.%. The Ras Qattara and Khatatba Formations have HI values ranging from 90 to 261 mgHC/gTOC, suggesting Types II-III and III kerogen. Vitrinite reflectance values range between 0.79 and 1.12 VRr %. Rock−Eval Tmax values in the range 438-458 °C indicate a thermal maturity level sufficient for hydrocarbon generation. Thermal and burial history models indicate that the Jurassic source rocks entered the mature to late mature stage for hydrocarbon generation in the Late Cretaceous to Tertiary. Hydrocarbon generation began in the Late Cretaceous and maximum rates of oil with significant gas have been generated during the early Tertiary (Paleogene). The peak gas generation occurred during the late Tertiary (Neogene). 相似文献
338.
A prominent feature of Titan's atmosphere is a thick haze region that acts as the end product of hydrocarbon and nitrile chemistry. Using a one-dimensional photochemical model, an investigation into the chemical mechanisms responsible for the formation of this haze region is conducted. The model derives profiles for Titan's atmospheric constituents that are consistent with observations. Included is an updated benzene profile that matches more closely with—recent ISO observations (Icarus 161 (2003) 383), replacing the profile given in the benzene study of Wilson et al. (J. Geophys. Res. 108 (2003) 5014). Using these profiles, pathways from polyynes, aromatics, and nitriles are considered, as well as possible copolymerization among the pathways. The model demonstrates that the growth of polycyclic aromatic hydrocarbons throughout the lower stratosphere plays an important role in furnishing the main haze layer, with nitriles playing a secondary role. The peak chemical production of haze layer ranges from 140 to 300 km peaking at an altitude of 220 km, with a production rate of 3.2×10−14 gcm−2 s−1. Possible mechanisms for polymerization and copolymerization and suggestions for further kinetic study are discussed, along with the implications for the distribution of haze in Titan's atmosphere. 相似文献
339.
H.-M. Schulz H. W. Hagemann M. Wolf A. Brammertz H.-J. Einbrodt 《Environmental Geology》1997,30(1-2):72-80
The fibrogenic and cytotoxic potential of coal mine dust is independent of the amount of quartz and other inorganic parameters.
Results of coal petrographical and organic geochemical investigations of coals and coal mine dust from the Ruhr and Ibbenbüren
Region of Germany demonstrate variations of organic dust amount possibly influencing these noxious properties. Coal mine dust
of high rank coals is characterized by a pronounced fibrogenic risk. This risk, independent of the quantity of quartz, is
probably based on shape variations of different coal macerals. With increasing coalification of the corresponding seam, the
vitrinite is enriched in its dust; however, lower concentrations have been determined for inertinite. Vitrinite shows constant
shapes and sizes independent of the rank of coal. Inertinite particles with elongated to fibrous shapes tend to larger sizes
with increasing coalification. Strikingly, coal mine dust from miners' lungs with high degrees of coal mine workers' pneumoconiosis
(CWP) is enriched in inertinite. In contrast, high cytotoxicities in cell tests are known for coal mine dust from low coalified
coals. High concentrations of phenolic compounds can be extracted by dichloromethane from low coalified coal mine dust. These
compounds, which are characterized by a high water solubility and therefore high bioavailability, explain the high cytotoxicities
of coal mine dust. Contamination of dust by diesel emissions in the coal mine can act as additionally supporting parameters
for extended cytotoxicities.
Received: 18 August 1995 · Accepted: 15 October 1995 相似文献
340.
Geochemical records of the sediments and their significance in Dongping Lake Area,the lower reach of Yellow River,North China
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Yu Lin-song Liu Hong-bo Wan Fang Hu Zun-fang Luo Huai-dong Zhang Xiu-wen 《地下水科学与工程》2021,9(2):140-151
Dongping Lake area, located in the lower reaches of Yellow River, is an ideal place to study the changes of modern river and lake sedimentary environment. The sediment samples of Dawen River, Yellow River, and Dongping Lake were collected, and the major elements, trace elements and organic matter geochemical composition of the samples were analyzed. Cluster analysis, characteristic element ratio method and graphic method were used to explore the geochemical characteristics of sediments and their environmental implication. The results show that the contents of SiO_2, Na_2O, TiO_2 and Zr in sediments of Dawen River and Yellow River are relatively high, and the contents of iron and manganese oxides, organic matter, CaO, P_2O_5 and Sr in lake sediments are relatively high. That reveals the differences of sedimentary environments between the rivers and the lake. The contents of Sr and Zr in Dawen River are affected by the rapid migration of clastic materials in the upstream carbonate source area during the flood season; the δCe,ΣREE and REE's ratios in the sediments of the Yellow River reflect the influence of the Loess source; and the distribution of elements changes along the flow direction during the flood season. The characteristics of p H, element composition and LREE HREE fractionation of the lake sediments indicate that the sediment source is complex, and the lake environment is affected by the flood season. The study shows that the geochemical content and its variation characteristics of sediments effectively reveal the sedimentary environment, material composition and characteristics of flood season of rivers and the lake in the study area. 相似文献