用BaCl2滴定法快速测定硫酸盐的研究

用铬酸钡光度法、EDTA滴定法、间接原子吸收法、离子色谱法等方法测定SO42-检测上限都很低(12-200mg/L),且只适用于清洁水,若水样混浊则全引起较大的误差.有的地下水,SO42-浓度高达44000mg/L,用BaCl2滴定法测定SO42-:测试水样,以溴酚蓝做酸碱指示剂,加1∶50盐酸,调为pH=3.5,加入30ml异丙醇,以钍试剂做终点指示剂,滴加0.01mol/L BaCl2,砖红色为终点,根据BaCl2用量计算SO42-浓度.本方法快捷、准确、测定范围大,上限可达2000mg/L,克服了光度法测定浑浊水样引起误差大的缺点.     

Ageism: A Factor in the Nutritional Vulnerability of Older People?

Unlike other population groups, the rights, needs and contributions of older people in developing countries are not well understood. With the absence of information about how to assess the nutritional status and vulnerability of older people, HelpAge International joined forces with the London School of Hygiene and Tropical Medicine in the early 1990s to launch a research programme. Seven years later some of the basic questions can now be answered but there remains much more to do.
Although older people are increasingly acknowledged as a vulnerable group in emergencies, NGO responses often fail to meet their needs. The question is whether there are real difficulties in service adaptation or whether ageism is one of the greatest barriers to the provision of appropriate services for older people.     

Diuron in surface runoff and tile drainage from two grass-seed fields

The typical method of cool-season grass-seed production in Mediterranean climates briefly exposes surface waters to potentially high concentrations of the herbicide diuron [3-(3,4-dichlorophenyl)-1,1-dimethyl urea] during the initial season of growth. To better understand the process, and the degree, of diuron transport from agricultural fields, two grass-seed fields in the Willamette Valley of Oregon were monitored for diuron loss in surface runoff and tile drainage during the first wet season after planting. Initial diuron concentrations in surface runoff were high (>1000 microg L(-1) in one field and >100 microg L(-1) in the other), though they decreased by two orders of magnitude by the end of the season. Concentrations in the tile drains were as much as 1000 times lower than in the surface runoff during the first few weeks of runoff events, and they remained lower than surface water concentrations throughout the season. Total losses in surface runoff were between 1.3 and 3% of the amount applied-much higher than losses via the tile drains. It is also shown by means of a simple first-order decay model that, when little information is available, it may be best to describe diuron depletion in runoff water as a function of cumulative rainfall during the wet season.     

用BaCl2滴定法快速测定硫酸盐的研究

用铬酸钡光度法、EDTA滴定法、间接原予吸收法、离子色谱法等方法测定SO4^2-检测上限都很低（12—200mg／L），且只适用于清洁水，若水样混浊则会引起较大的误差。有的地下水，SO4^2-浓度高迭44000mg／L，用BaCl2滴定法测定SO4^2-：测试水样，以溴酚蓝做酸碱指示剂，加1：50盐酸，调为pH=3．5，加入30ml异丙醇，以钍试荆做终点指示荆，滴加0．01mol／L BaCl2，砖红色为终点，根据BaCl2用量计算SO4^2-浓度。本方法快捷、准确、测定范围大，上限可迭2000mg／L，克服了光度法测定浑浊水样引起误差大的缺点。     

Designing Systematic Conservation Assessments that Promote Effective Implementation: Best Practice from South Africa

Abstract:  Systematic conservation assessment and conservation planning are two distinct fields of conservation science often confused as one and the same. Systematic conservation assessment is the technical, often computer-based, identification of priority areas for conservation. Conservation planning is composed of a systematic conservation assessment coupled with processes for development of an implementation strategy and stakeholder collaboration. The peer-reviewed conservation biology literature abounds with studies analyzing the performance of assessments (e.g., area-selection techniques). This information alone, however, can never deliver effective conservation action; it informs conservation planning. Examples of how to translate systematic assessment outputs into knowledge and then use them for "doing" conservation are rare. South Africa has received generous international and domestic funding for regional conservation planning since the mid-1990s. We reviewed eight South African conservation planning processes and identified key ingredients of best practice for undertaking systematic conservation assessments in a way that facilitates implementing conservation action. These key ingredients include the design of conservation planning processes, skills for conservation assessment teams, collaboration with stakeholders, and interpretation and mainstreaming of products (e.g., maps) for stakeholders. Social learning institutions are critical to the successful operationalization of assessments within broader conservation planning processes and should include not only conservation planners but also diverse interest groups, including rural landowners, politicians, and government employees.     

PRINCIPLES FOR INTERNATIONAL GROUND-WATER LAW (I)

International ground-water resources have not received their full share of legal investigation. This paper outlines some principles applicable to the development of international co-operation concerning this important resource, bearing in mind that ground and surface waters are the same resource. In the absence of positive international law covering ground-water resources, national laws are investigated to examine their suitability for adaptation to the international level. In a second paper, to be published in the next issue of the Forum , the interjurisdictional experience among federated states and among independent states will be reviewed.     

Ageism: a factor in the nutritional vulnerability of older people?

Unlike other population groups, the rights, needs and contributions of older people in developing countries are not well understood. With the absence of information about how to assess the nutritional status and vulnerability of older people, HelpAge International joined forces with the London School of Hygiene and Tropical Medicine in the early 1990's to launch a research programme. Seven years later some of the basic questions can now be answered but there remains much more to do. Although older people are increasingly acknowledged as a vulnerable group in emergencies, NGO responses often fail to meet their needs. The question is whether there are real difficulties in service adaptation or whether ageism is one of the greatest barriers to the provision of appropriate services for older people.     

An integrated tool to assess the role of new planting in PM10 capture and the human health benefits: A case study in London

The role of vegetation in mitigating the effects of PM₁₀ pollution has been highlighted as one potential benefit of urban greenspace. An integrated modelling approach is presented which utilises air dispersion (ADMS-Urban) and particulate interception (UFORE) to predict the PM₁₀ concentrations both before and after greenspace establishment, using a 10 × 10 km area of East London Green Grid (ELGG) as a case study. The corresponding health benefits, in terms of premature mortality and respiratory hospital admissions, as a result of the reduced exposure of the local population are also modelled. PM₁₀ capture from the scenario comprising 75% grassland, 20% sycamore maple (Acer pseudoplatanus L.) and 5% Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) was estimated to be 90.41 t yr⁻¹, equating to 0.009 t ha⁻¹ yr⁻¹ over the whole study area. The human health modelling estimated that 2 deaths and 2 hospital admissions would be averted per year.     

Deposition and solubility of airborne metals to four plant species grown at varying distances from two heavily trafficked roads in London

In urban areas, a highly variable mixture of pollutants is deposited as particulate matter. The concentration and bioavailability of individual pollutants within particles need to be characterised to ascertain the risks to ecological receptors. This study, carried out at two urban parks, measured the deposition and water-solubility of metals to four species common to UK urban areas. Foliar Cd, Cr, Cu, Fe, Ni, Pb and Zn concentrations were elevated in at least one species compared with those from a rural control site. Concentrations were, however, only affected by distance to road in nettle and, to a lesser extent, birch leaves. Greater concentrations of metal were observed in these species compared to cypress and maple possibly due to differences in plant morphology and leaf surfaces. Solubility appeared to be linked to the size fraction and, therefore, origin of the metal with those present predominantly in the coarse fraction exhibiting low solubility.     

PRINCIPLES FOR INTERNATIONAL GROUND-WATER LAW (II)

This is the second part of a paper outlining some principles applicable to the development of international law in the sub-sector of ground-water resources. In the first part of the paper, in the previous issue of the Forum , national ground-water laws were investigated to examine their suitability for adaptation at the international level. This part of the paper is devoted to reviewing the interjurisdictional experience among federated states and among independent states. It also draws the general conclusion of the entire paper.