Copper ecotoxicology of marine algae: a methodological appraisal

The production of accurate and reliable data on copper ecotoxicology of marine algae depends on the use of trace metal clean techniques during experimentation. We reviewed the methodologies used in the literature on copper ecotoxicology of marine macro- and microalgae, specifically the use of trace metal clean procedures such as the labware used (glassware vs. plasticware), methods of cleaning the labware (acid soaking and ultrapure water rinsing), stock solution preparation (copper source and acidification), and measurement and reporting of dissolved copper concentrations. In terms of taxonomic classification, the most studied algal groups were the Phyla Ochrophyta, Bacillariophyta, Rhodophyta, and Chlorophyta. In terms of methodology, ～50% of the articles did not specify the labware, ～25% used glassware, and ～25% plasticware; ～30% of the studies specified cleaning protocols for labware to remove trace metal impurities; the copper form used to prepare the stock solutions was specified in ～80% of studies but acidification to stabilise the dissolved copper was performed in only ～20%; and the dissolved copper concentration was measured in only ～40% of studies. We discuss the importance of following trace metal clean techniques for the comparison and interpretation of data obtained on copper ecotoxicology in algae.     

Market efficiency,filter rules and buffer stock profitability

This paper uses a model of the optimum buffer stock as a ‘filter rule’ together with a financial model that can be used to assess the efficiency of international commodity markets. The approach is simpler to apply than many other methods which have hitherto been used and yields an economy in theoretical and computational effort. The arguments are applied as a case study to the international copper market. The main conclusion is that private storage is not under-provided for and that a public buffer stock agency would be unlikely to be self-financing.     

Copper in India: Present and future outlook

The availability of mineral resources plays an important role in India's national economy. Copper, one of the important non-ferrous metals, has various industrial uses and demand for it is increasing in India where the inventory and production of copper, though not comparable with developed countries, shows an impressive growth rate, particularly during the last decade. With an increasing rate of industrial production envisaged in future plans copper consumption is expected to rise. Logistic curves have been used to study the potential long-term production capability under the dynamic concept of reserves and resources, with curves drawn for various estimates of total available resources. The production figures shown are not final and are subject to change due to a number of factors. This approach merely provides a method for projecting trends in future production.     

Hydrogeochemical and mineralogical characteristics related to heavy metal attenuation in a stream polluted by acid mine drainage: A case study in Dabaoshan Mine, China

Dabaoshan Mine, the largest mine in south China, has been developed since the 1970s. Acid mine drainage (AMD) discharged from the mine has caused severe environmental pollution and human health problems. In this article, chemical characteristics, mineralogy of ocher precipitations and heavy metal attenuation in the AMD are discussed based on physicochemical analysis, mineral analysis, sequential extraction experiments and hydrogeochemistry. The AMD chemical characteristics were determined from the initial water composition, water-rock interactions and dissolved sulfide minerals in the mine tailings. The waters, affected and unaffected by AMD, were Ca-SO₄ and Ca-HCO₃ types, respectively. The affected water had a low pH, high SO₄^2- and high heavy metal content and oxidation as determined by the Fe²⁺/Fe³⁺ couple. Heavy metal and SO₄^2- contents of Hengshi River water decreased, while pH increased, downstream. Schwertmannite was the major mineral at the waste dump, while goethite and quartz were dominant at the tailings dam and streambed. Schwertmannite was transformed into goethite at the tailings dam and streambed. The sulfate ions of the secondary minerals changed from bidentate- to monodentate-complexes downstream. Fe-Mn oxide phases of Zn, Cd and Pb in sediments increased downstream. However, organic matter complexes of Cu in sediments increased further away from the tailings. Fe³⁺ mineral precipitates and transformations controlled the AMD water chemistry.     

煤矿开采矿山地质环境问题类型和特征探讨

我国煤炭资源赋存丰富且条件复杂,历年开采引发或加剧众多矿山地质环境问题。本文以煤炭资源开发各环节活动及开采形式为基础．分析和探讨了煤矿建设和生产对矿山地质环境的影响,探讨了问题类型及特征,并给出了不同开采形式对矿山地质环境影响的关系,并提出了矿山地质环境问题防治工作进一步开展的几点建议,对我国发展绿色、高效矿山有一定促进作用。     

Effects of copper chloride on formation of polychlorinated dibenzo-p-dioxins in model waste incineration

Combustion experiments in a laboratory-scale fluidized-bed reactor were conducted to elucidate the effects of copper chloride as a catalyst on polychlorinated dibenzo-p-dioxins (PCDDs) formation in municipal waste incineration. We used model wastes with and without copper chloride (CuCl₂ · 2H₂O), both of which contained polyvinyl chloride as a chlorine source. Combustion temperature was set to 900 °C, and the amount of air supplied was twice the stoichiometric ratio. The experimental setup was carefully planned to suppress the influences of experimental conditions except the waste composition. Results of these experiments showed that copper chloride in the waste increased the amount of PCDDs formed and made the homologue profile to shift towards the highly chlorinated species. Copper chloride contributes to the PCDDs formation by promoting chlorination, whereby the reaction is important in that organic matter is chlorinated directly by copper compounds. Copper chloride did not exert a great influence on the isomer distribution patterns of PCDDs, while there appeared a significant difference in the case of PCDFs. This points out the difference of the major formation mechanisms between PCDDs and PCDFs. PCDDs are less formed by the catalytic reactions from carbon/polycyclic aromatic hydrocarbons than PCDFs in our experimental conditions.     

Joint toxicity of copper and diazinon during embryonic and larval development of the common South American toad,Rhinella arenarum

Copper (Cu) and diazinon are two widely distributed pollutants; they coexist in agro-ecosystems and cause toxicity to wild biota. This study proposes to analyse the joint toxicity of binary mixtures of Cu and diazinon on the early development of the South American toad, Rhinella arenarum by means of a standardised test. Cu was always more toxic than diazinon. Cu was more embryotoxic while the pesticide was more toxic during the larval exposure than during the embryonic period. The different Cu/diazinon mixtures proportions assayed were significantly less toxic than expected by additive effects. Thus, an antagonistic interaction pattern was observed. This pattern was independent of the assayed proportion, the exposure times and the exposure developmental periods. In the risk assessment analysis to establish water quality criteria, the joint toxicity should be considered at different ratios, exposure time and life period for a certain species, in order to preserve wild species.     

Comprehensive monitoring technique based on electromagnetic radiation and its applications to mine pressure

Strata pressures are common potential troubles during coal mining, serious ones can cause great catastrophe. This paper presents a new comprehensive electromagnetic radiation (EMR) monitoring technique to monitor and predict these disasters. In this paper, we studied the relationship of EMR emitted by various, uniaxially loaded, coal rock samples (coal, rock, roof-coal-floor composite) in their whole deformation and failure processes to the applied loads, and found that EMR signal is linearly related to the applied loads, while the number of EMR pulses is a third power function of the applied loads. Therefore, EMR signal is capable of reflecting the stress (load) state, deformation and fracture strength, and internal stress state of coal rock mass. Based on the above, we proposed three methods for measuring rock pressure distribution, periodic pressure, and internal stress distribution of coal rock mass on working faces, and conducted field measurements and verifications. The results showed that (i) EMR has a certain correspondence to support resistance of working faces, and can reflect more accurately the face pressure distribution; (ii) in the mining impacted area located within 100 m in the front of working face, the stress distribution has unimodal and bimodal forms; (iii) EMR signal changes periodically with periodic pressure, and can be used to qualitatively observe and evaluate periodic pressure; (iv) tested with antenna in the borehole into coal rock mass, EMR signal can effectively reflect the internal stress distribution and shifting, which was verified by using traditional drilling cuttings method. In addition, EMR can also be used to check the effect of destress blasting as one of the emergency measures. In conclusion, the results are of practical significance for using EMR to monitor rock pressure and guiding safe underground mining.     

云南省玉龙县碳减排效应估算

玉龙县碳减排效应估算主要包括退耕还林、造林、小水电、替代能源(包括沼气池和太阳能)使用等方面. 其中,造林具有较长期的碳汇功能,会持续提供碳增汇服务功能;替代能源的使用可以有效减少薪柴燃烧,在以农村人口为主的玉龙县,薪柴是主要的取暖和生活能源,故替代能源的使用颇具意义. 以2005年为基准年,小水电和替代能源总的碳减排效应为22.24×103 t,其中小水电碳减排效应为14.43 ×103 t,太阳能碳减排效应为66.24 t,沼气池碳减排效应为7.74×103 t;设定了基准年后林木生长过程以及替代能源使用状况的情景,并进行情景模拟,估算了玉龙县造林在5年内会产生碳汇21.07×103 t,10年内会产生碳汇24.92×103 t. 在研究区总的碳减排效应中,小水电、沼气池以及生态林地都有较大贡献,而经济林和草地的贡献相对较小;与5年情景相比,20年情景中小水电和沼气池的贡献有所上升,而生态林地等的贡献相对下降.      

海南昌江石碌钴铜矿尾矿库重金属污染环境现状调查

为了解海南省昌江县石碌镇钴铜矿尾矿库环境特点,分别采集了矿砂、背景土壤、废水、纳污水体和植物进行分析。结果表明,钴铜矿尾矿库的土壤受As和Cu污染严重,周边土壤受到不同程度的重金属污染;废水经过尾矿库沉淀处理后,SS、As、Cu、Co、Fe等监测指标均有所降低,尾矿库起到沉淀吸附处理作用;纳污河流石碌河水质良好;尾矿库内自然生长的菖蒲和水竹均受到重金属不同程度污染,尾矿库内的甘蔗中Cr、Pb含量均超过食品中污染物限量标准,表明尾矿库内不宜种植可食用作物。