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121.
Fractionation of Cu, Pb and Zn in certified reference soils SRM 2710 and SRM 2711 using the optimized BCR sequential extraction procedure 总被引:4,自引:0,他引:4
Sequential extraction of metals from solid media is a common analytical tool used in environmental and exploration geochemistry. A number of procedures exist, but without harmonization and standardization, meaningful comparisons are tenuous without baseline data. A newly developed, standardized sequential extraction procedure (optimized BCR) was applied to two contaminated certified reference soils from Montana, US (SRM 2710 and SRM 2711) for Cu, Pb and Zn. Four operationally defined fractions were isolated, acid extractable, reducible, oxidizable, and residual (by aqua regia). Fraction-specific concentrations, percentages and recoveries for Cu, Pb and Zn were used to explore differences between the optimized BCR procedure and three other sequential extraction schemes with published data for SRM 2710 and 2711 (i.e. Tessier scheme, Geological Survey of Canada scheme and the original BCR scheme). Results indicate significant differences between the four schemes, even for schemes that are closely associated (i.e. the original and optimized BCR schemes). Order-of-magnitude fraction-specific concentration differences were observed, especially for Pb in the reducible fraction. Differences between schemes are worrisome because trends varied between metals, between fractions and between reference soils. These data reinforce the need for increased adoption of standardized sequential extraction procedures and further examination of different solid media. 相似文献
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Li Yongmei Li Wenshu Gu Guowei 《Frontiers of Environmental Science & Engineering in China》2007,1(4):493-497
Batch experiments were carried out to investigate the promotive effect of pyridine on indole degradation under denitrifying
conditions. The seed sludge was obtained from a local coal-coking wastewater treatment facility and was acclimated in the
laboratory. Indole and pyridine were supplemented to the synthetic wastewater at different ratios. The optimum ratio of chemical
oxygen demand (COD) to nitrate (C/N) was 8.4–8.9 for both denitrification and indole and pyridine degradation. At a temperature
of 28°C and pH of 7.0–7.5, the nitrate reductase activity (NRA) was in the best state. The addition of pyridine could promote
NRA and the degradation of indole. When the initial concentration of indole was 150 mg/L, the concentration ratio of indole
to pyridine was in the range of 1–10. Under optimum C/N conditions, the degradation of indole could be described with pseudo-zero-order
kinetics. There was no accumulation of nitrite during the reaction. When the concentration ratio of pyridine to indole was
less than 0.25 with an increase in the pyridine proportion, there were more significant augment rates for NRA and the degradation
of indole than the situation when the concentration ratio was more than 0.25.
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Translated from Environmental Science, 2006, 27(2): 300–304 [译自: 环境科学] 相似文献
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1969年。经由瑞典政府提议.联合国大会决定1972年在瑞典首都斯德哥尔摩召开联合国人类环境会议。这是联合国历史上首次以环保为主题的会议.是人类环境意识觉醒的标志.在人类社会发展史上具有里程碑式的意义。1972年6月5日,会议在斯德哥尔摩隆重开幕。133个国家的1300多名代表出席了这次会议。会议通过了《联合国人类环境会议宣言》和《行动计划》。宣告了人类环境新观念的诞生,达成了“只有一个地球”.人类与环境是不可分割的“共同体”的共识。1972年6月5日。全球环境保护的航船从斯德哥尔摩启航。33年过去了,让我们重回斯德哥尔摩,去寻找历史的轨迹.去了解这座环保之都的未来航向。[编者按] 相似文献
129.
E. Lamla F. Boschke G. Traving G. Pfotzer H. Wolter W. Walcher H. D. Dahmen H. J. Queisser W. W. Klingbeil K. Beyermann O. Müller R. R. Ernst D. Reinen H. Muth W. Becker G. Wunsch G. I. Distler L. Jaenicke H. G. v. Schnering H. Werner F. Reiff H. Schimassek W. Höll H. K. Vasil W. F. Angermeier W. Ruppel J. C. Eccles G. Spiteller H. Oettel W. Vogell P. Brosche K. J. Hsü H. -U. Schmincke 《Die Naturwissenschaften》1975,62(3):143-143
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