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841.
Small-scale mining in China: Assessing recent advances in the policy and regulatory framework 总被引:1,自引:0,他引:1
This paper explores the background of a proposed revision to the Mineral Resources Law of China, why and how the law was amended in the past, its salient features and objectives. Of equal importance is an analysis of how this national law, with its attendant regulations and policies, formed the basis for the growth and continued development of China's small-scale mining industry. The Xiaoqingling Gold Mountain case study is shown to justify the necessity and feasibility for formalizing and consolidating small-scale mines in China, and to some extent, the success of the nation-wide ASM resource consolidation policy at a local level. 相似文献
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The accumulation and depuration of Cs in the green mussels (Perna viridis) commonly found in the subtropical and tropical waters were studied under the laboratory conditions using radiotracer techniques.
Following an initial rapid sorption onto the mussel's tissues, uptake of Cs exhibited linear patterns over a short exposure
time (8 h) at different ambient Cs concentrations. The concentration factor was independent of ambient Cs concentration. The
calculated uptake rate and initial sorption constant of Cs were directly proportional to the ambient Cs concentration. The
calculated uptake rate constant from the dissolved phase in the mussels was as low as 0.026 l g−1 d−1. Uptake rates of Cs in the mussels were inversely related to the ambient salinity. Uptake increased about twofold when the
salinity was reduced from 33 to 15 ppt. The effect of salinity on Cs uptake was primarily due to the change in ambient K+ concentration. The uptake rate decreased in a power function with increasing tissue dry weight of the mussels, although the
initial sorption was not related to the mussel's body size. The efflux rate constant of Cs in the mussels was 0.15 to 0.18 d−1, and was the highest recorded to date among different metals in marine bivalves. The efflux rate constant also decreased
in a power function with increasing tissue dry weight of mussels. A simple kinetic model predicted that the bioconcentration
factor of Cs in the green mussels was 145, which was higher than measurements taken in their temperate counterparts. The bioconcentration
factor also decreased in a power function with increasing tissue dry weight of mussels.
Received: 27 October 1999 / Accepted: 16 June 2000 相似文献
845.
Degradation of polycyclic aromatic hydrocarbons by a bacterial consortium enriched from mangrove sediments 总被引:2,自引:0,他引:2
The biodegradability of a polycyclic aromatic hydrocarbons (PAHs) mixture consisted of fluorene (Fl), phenanthrene (Phe) and pyrene (Pyr) by a bacterial consortium enriched from mangrove sediments under sediment-free and sediment slurry conditions was investigated. The enriched consortium made up of three bacterial strains, namely Rhodococcus sp., Acinetobacter sp. and Pseudomonas sp., had a good PAH degradation capability with 100% degradation of Fl and Phe in sediment-free liquid medium after 4 weeks of growth. The Fl and Phe degradation percentages in sediment slurry were higher than that in liquid medium. Autochthonous microorganisms in sediments also possessed satisfactory PAH degradation capability and all three PAHs were almost completely degraded after 4 weeks of growth. Bioaugumentation (inoculation of the enriched consortium to sediments) showed a positive effect on PAH biodegradation after 1 week of growth. Complete biodegradation of pyrene took longer time than that for Fl and Phe, indicating the enriched bacterial consortium had preference to utilize low-molecular weight PAHs. 相似文献
846.
Nitrocellulose membrane (NCM) can produce hydroxyl radicals under illumination, which promotes the oxidative degradation of organic pollutants. In this paper, NCM was used to oxidize bisphenol A (BPA) under simulated sunlight. The effects of pH, temperature, light intensity, anion and cation on the degradation of BPA were analyzed. The photodegradation process of BPA was discussed. The optimal photolysis rate was 0.031 min?1 when the temperature was 30°C, the light intensity was 2.67 × 104 Lux, and the pH value was 9.0. The alkaline environment, temperature and light intensity can promote the photodegradation of BPA. Except for nitrate ions, anions and cations can inhibit the photodegradation of BPA. Compared with cations, anions have a greater inhibitory effect on BPA degradation. The degradation products of BPA by NCM were analyzed by gas chromatographic/mass. This study may provide useful information for the BPA degradation by NCM in complex water samples. 相似文献
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集成电路产业含氟废水处理工程 总被引:3,自引:0,他引:3
介绍采用三级反应一级沉淀为主体工艺,处理集成电路产业含氟废水的实际应用情况和工程治理效果。实践表明,采用本处理技术,能确保出水水质氟离子浓度达到上海市《污水综合排放标准》(DB31/199-1997)的二级标准,即F-浓度≤10mg/L。 相似文献