西昌邛海水质现状调查分析

四川西昌的邛海水体中浮游植物群体组成以硅藻、绿藻及鼓藻为主，据1986～1991年连续监测结果表明，邛海水质总体处于贫营养状况，仅局部有富营养性藻类出现。     

隧道安全事故分析与安全施工措施探讨

全面分析隧道安全事故并根据事故原因提出相应的安全施工措施，对于隧道施工企业营造企业安全文化，提高企业管理水平，具有重要的现实意义。本文根据多年的施工管理经验，分析了隧道施工过程中常见的安全事故，提出了隧道安全施工的措施。     

点源基于地表水质排放限值制度设计

针对我国点源排放标准不能确保具体点源所排入的水体地表水质达标的问题,借鉴美国点源基于地表水质排放限值的规则和方法的经验,论证我国建立点源基于地表水质排放限值的必要性,提出点源基于地表水质排放限值的制度框架,并提出政策建议：在法规中补充点源基于地表水质排放限值的相关要求;明确点源排污许可证的制定必须要计算点源基于地表水质的排放限值,并采取与已有的排放标准中严者作为点源的排放限值;授权省级政府制定混合区划定法规.     

A comprehensive review of hydrophobic silica and composite aerogels: synthesis,properties and recent progress towards environmental remediation and biomedical applications

Environmental Science and Pollution Research - The hydrophobicity of silica and composite aerogels has enabled them to acquire applications in a variety of fields. With remarkable structural,...     

Fuelwood assessment at micro-watershed level in Northeast Himalaya:a case study in Manipur,India

Fuelwood is one of the major sources of energy in the domestic sector across the rural areas,especially in the developing regions across the world.The Northeastern Himalayan state of Manipur is dominated by the tribal population that largely depends on fuelwood from the nearby forest area.The entire dependence on forests for energy resources is affecting the sustainability of the forest ecosystem in the region,thus indicating the livelihood conditions.Since land-use land-cover change is the key driver to the change in resource availability of a region,the present study has tried to analyze the landcover changes over a period 28 years.The second major component affecting resource availability is the increasing population pressure that leads to changes in the land dynamics,which directly affect the resource production.Based on the existing consumption pattern,the total consumption of fuelwood in the watershed ranges fiom a minimum of 289.992 tons/year to a maximum of 3545.719 tons/year with an average of 1561.956 tons/year in the year 2009 and simulated fuelwood consumption for the year 2021 is around 1469.260 tons/year.Nine different probable scenarios of resource are proposed to calculate the stress value that can be used by the policy-makers and planners for suitable policy implementation at the micro level with a complex social system.     

De-fluoridation of groundwater using magnesium oxide

Fluorosis, which severely affects teeth and bones, is one of the common water-related diseases listed by the World Health Organization. Fluorosis is caused by ingestion of groundwater containing fluoride in excess of 1.5 mg/l and is widespread in about 25 countries. As majority of fluorosis affected regions occur in arid or semi-arid regions of the world, de-fluoridation of the limited available water resource forms the viable solution. Though several methods of de-fluoridation have been proposed, only few are implemented in field. Further, the existing field methods have various limitations such as cost, efficiency, quality of treated water and disposal of byproducts of treatment. In search of a sustainable solution towards mitigating the fluorosis problem, a new method of de-fluoridation using magnesium oxide has been developed in laboratory. Present study addresses issues that will assist in successful implementation of the new de-fluoridation method in field, using a domestic de-fluoridation unit.     

Amberlite XAD-7 impregnated with morpholine dithiocarbamate as trace metal extractant

Application of Amberlite XAD-7 impregnated with morpholine dithiocarbamate (MDTC) for separation and preconcentration of trace amounts of lead, copper, cobalt, iron, nickel, cadmium and zinc and determination by ICP-AES has been described. The optimum experimental parameters, such as pH, sample flow rate, eluent and effect of matrix ions on the preconcentration were investigated. Simultaneous enrichment of the seven metals was accomplished. The t _1/2 values for sorption are 2.9, 3.3, 3.7, 3.6, 2.8, 4.1 and 2.8 respectively for Pb(II), Cu(II), Co(II), Fe(III), Ni(II), Cd(II) and Zn(II). The method was applied for the determination of trace metal ions in seawater and natural water samples. The results have been compared with extraction GFAAS method.     

Cosolvent-enhanced chemical oxidation of perchloroethylene by potassium permanganate

A laboratory study was conducted to examine cosolvent-enhanced in-situ chemical oxidation (ISCO) of perchloroethylene (PCE) using potassium permanganate (KMnO4). The conceptual basis for this new technique is to enhance permanganate oxidation of dense non-aqueous phase liquids (DNAPLs) with the addition of a cosolvent, thereby increasing DNAPL solubility while avoiding mobilization. Among 17 cosolvent candidates screened, tertiary butyl alcohol (TBA) and acetone were the most stable in the presence of KMnO4, both of which increased PCE aqueous solubility significantly, and therefore are suitable to be used as cosolvent in this study. Batch experiments indicated that the second-order rate constant for PCE oxidation by potassium permanganate was 0.043+/-0.002 M(-1) s(-1) in the purely aqueous (no cosolvent) solution. In the presence of 20% cosolvent (volume fraction=fc=0.2), the rate constant decreased to 0.036+/-0.003 M(-1) s(-1) with TBA and to 0.031+/-0.002 M(-1) s(-1) with acetone. However, in the presence of free-phase PCE, chloride ion concentration from PCE oxidation in acetone/water solutions (fc=0.2) was about twice that in aqueous solutions, indicating that the increase in PCE solubility more than compensated for the decrease in reaction rate constant, such that the oxidation efficiency of PCE was increased with cosolvent. A complete chlorine mass balance was observed in the aqueous system, whereas approximately 70% was obtained in TBA/water or acetone/water (fc=0.2). In soil columns containing residual DNAPL and subjected to isocratic flushing with step-wise increases in f(c) cosolvent, TBA at fc=0.2 resulted in PCE mobilization, whereas acetone at fc相似文献