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101.
Mark S. Davies 《Water research》1992,26(12):1691-1693
Toxicological modification of molluscan mucus production has largely been ignored. This is probably due to an underestimation of the r
le of mucus in molluscan physiology and its energetic cost. This paper reports that laboratory exposure to episodic doses of waterborne copper and zinc serve to reduce pedal mucus production by the common limpet Patella vulgata L. to about 60% of the unstressed rate. The metals are effective in this respect at concentrations as low as 10 μg l−1, which in the case of zinc is below the current U.K. environmental quality standard. All metal doses reduced mucus production to the same level. This suggests a behavioural response of the limpet, limiting activity. The reduction in mucus production has important consequences both for limpet ecology and for the ways in which biological energy allocation and transformation are assessed. 相似文献
102.
G. Perin R. Fabris S. Manente A.Rebello Wagener C. Hamacher S. Scotto 《Water research》1997,31(12):3017-3028
Surface sediments of the Guanabara Bay (Rio de Janeiro, Brazil) were analyzed by a sequential extraction procedure for Cd, Cr, Cu, Pb, Zn, Mn and Fe, determining their distribution among five geochemical phases and in the nitric acid extractable phase. Bioavailable phases and non-bioavailable phases have been determined in six transects in the bay to define the significant level of pollution due to sediment metal contamination. A multiple correlation showed limited responsibility of Mn and Fe oxides and humic acids in the adsorption process, which allowed discrimination among the different processes and suggested the strong influence of the hydrogen sulfide present in the highly reduced bay bottom environment. The authors suggest the need to avoid disturbing bottom sediment by dredging or by artificial bottom aeration which could result in a rapid worsening of the environment due to the accelerated formation of more soluble oxygenated metal compounds making the toxic metals much more available to the benthic fauna and to the bay biota in general. 相似文献
103.
随着建筑市场的规范和市场化日渐成熟,建筑企业在招投标,施工的管理过程中,“九大员”越来越体现出它的重要性和非常性,如何充分发挥“九大员”在施工过程中的作用,明确“九大员”在施工过程中的职责,协调“九大员”在施工过程的工作内容,奖惩“九大员”在施工过程中的功过,又是目前建筑界一个新课题。 相似文献
104.
Thenmozhi Murugaian Palanivel 《The International journal of environmental studies》2020,77(3):432-446
ABSTRACT Abandoned mine areas exhibit heavy metal contamination. This severely reduces the soil quality. This paper concerns the assessment of soils near an abandoned copper mine in Lasail, northern Oman. Seventy-two soil samples were collected and analysed for heavy metals using inductively coupled plasma optical emission spectrometry (ICP-OES). The extent of heavy metal pollution was evaluated based on the geo-accumulation index (Igeo), enrichment factor (EF), and pollution index (PI). According to these indices, Copper (Cu), Mercury (Hg), Zinc (Zn), Arsenic (As) and Iron (Fe) are impacting the soils. Of these, Cu and Hg concentrations are 50 and 300 times more than the permissible limits set by the World Health Organization (WHO). There is an urgent need for the remediation and restoration of the soils in this area and a proposal is presented here. 相似文献
105.
结合具体工程实际,提出采用强夯和强夯置换法进行地基加固处理的方案,阐述了强夯法加固地基技术的优点和适用范围,分析了强夯法和强夯置换法的作业机理,详细介绍了强夯施工工艺,指出该方案的应用大大提高了工程效益和社会效益。 相似文献
106.
J.B. Lefers W.F. van den Broeke H.W. Venderbosch J. de Niet A. Kettelarij 《Water research》1987,21(11)
Waste water from wet lime(stone) gypsum flue gas desulfurization processes for coal-fired boilers contains suspended solids (gypsum, silica, hydroxides of iron and aluminum) and soluble salts (chlorides and sulfates of calcium, sodium and magnesium). Furthermore, small amounts of heavy metals such as As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se and Zn are present in these waste water streams. A treatment method has been developed to remove these heavy metals very efficiently. This method has been based on coprecipitation of metal hydroxides and sulfides. The hydroxide and sulfide precipitates are removed by a coagulation/flocculation technique followed by gravity settling. The coprecipitation can be carried out with sodium hydroxide or with lime. Both cases were investigated in two different pilot plants with synthetically composed waste water and with actual waste water from three different types of wet lime(stone)—gypsum flue gas desulfurization plants (lime—gypsum FGD plants without a prescrubber, one using seawater and another using river water as process water; a limestone—gypsum FGD plant with a prescrubber using river water as process water). 相似文献
107.
Tungsten heavy alloys possess a unique combina-tion of high density,strength and toughness.Theyare used extensively as kinetic energy penetrators.The factors to decide the properties of tungsten alloyinclude:Wcontent,Ni/Fe ratio,molding technologyand defo… 相似文献
108.
阐述了重油燃料在当前浮法玻璃生产中的使用现状,简要介绍了煤焦油代替重油的技术分析.通过煤焦油技术改造,每年可节约成本3006万元. 相似文献
109.
110.
硫酸盐还原菌(SRB)法是一种极具潜力的酸性矿山废水(AMD)处理技术,如何将多种重金属分级沉淀并且分相分离出来,是SRB工艺走上工程应用的关键。本文综述了SRB法固定AMD中重金属的国内外研究进展,主要包括SRB法去除AMD中重金属的原理、SRB法分级沉淀AMD中多种重金属的工艺(分离式多级pH控制工艺及厌氧折流板反应器工艺)和SRB法厌氧污泥中金属硫化物的生物矿化(SRB介导的生物矿化成矿、生物矿化成矿影响因素及生物矿化过程微观机理),分析了此方面研究工作存在的问题。最后文章针对SRB法的深入研究及应用进行展望,认为硫酸盐还原体系中硫化物成矿的调控、成矿物相演变与微生物群落演替过程的解析以及矿化固定AMD中重金属成矿机理的探索将是今后重点关注的研究内容。 相似文献