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Isotopic Geochemistry of Cadmium:A Review 被引量:3
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作者 ZHU Chuanwei WEN Hanjie +2 位作者 ZHANG Yuxu LIU Yizhang WEI Rongfei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第6期2048-2057,共10页
Cadmium(Cd) is a scarce, but not an extremely rare element in the Earth's crust(crustal average: 0.2 ppm Cd). Geochemically, Cd exhibits thiophile, lithophile, and volatile behavior in different geologic process... Cadmium(Cd) is a scarce, but not an extremely rare element in the Earth's crust(crustal average: 0.2 ppm Cd). Geochemically, Cd exhibits thiophile, lithophile, and volatile behavior in different geologic processes. Biologically, it is a nutrient-like element that is closely related to P and Zn and is toxic element to organisms. Presently, Cd isotopes have been successfully utilized to trace Cd sources and nutrient cycling in marine systems in addition to unearthing other geochemical processes. Using published studies and our recent work, this survey summarizes the chemical preparation and mass spectrometry of Cd isotopes. It also reviews Cd isotopic compositions and fractionation mechanisms in nature as well as experiments. 展开更多
关键词 CADMIUM non-traditional stable isotopes stable isotopic fractionation geochemical tracer
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Potential for natural and enhanced attenuation of sulphanilamide in a contaminated chalk aquifer 被引量:2
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作者 Karen A.Bennett Simon D.Kelly +1 位作者 Xiangyu Tang Brian J.Reid 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第12期39-48,共10页
Understanding antibiotic biodegradation is important to the appreciation of their fate and removal from the environment. In this research an Isotope Ratio Mass Spectrometry(IRMS)method was developed to evaluate the ... Understanding antibiotic biodegradation is important to the appreciation of their fate and removal from the environment. In this research an Isotope Ratio Mass Spectrometry(IRMS)method was developed to evaluate the extent of biodegradation of the antibiotic,sulphanilamide, in contaminated groundwater. Results indicted an enrichment in δ^(13)C of8.44‰ from-26.56(at the contaminant source) to-18.12‰(300 m downfield of the source).These results confirm reductions in sulphanilamide concentrations(from 650 to 10 mg/L)across the contaminant plume to be attributable to biodegradation(56%) vs. other natural attenuation processes, such as dilution or dispersion(42%). To understand the controls on sulphanilamide degradation ex-situ microcosms assessed the influence of sulphanilamide concentration, redox conditions and an alternative carbon source. Results indicated, high levels of anaerobic capacity(~50% mineralisation) to degrade sulphanilamide under high(263 mg/L), moderate(10 mg/L) and low(0.02 mg/L) substrate concentrations. The addition of electron acceptors; nitrate and sulphate, did not significantly enhance the capacity of the groundwater to anaerobically biodegrade sulphanilamide. Interestingly, where alternative carbon sources were present, the addition of nitrate and sulphate inhibited sulphanilamide biodegradation. These results suggest, under in-situ conditions, when a preferential carbon source was available for biodegradation, sulphanilamide could be acting as a nitrogen and/or sulphur source. These findings are important as they highlight sulphanilamide being used as a carbon and a putative nitrogen and sulphur source, under prevailing iron reducing conditions. 展开更多
关键词 Antibiotics Sulphonamide Groundwater contamination Biodegradation stable isotope fractionation IRMS
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