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1.
A statistical quality control approachto detect changes in groundwater quality from aregulated waste unit is described. The approachapplies the combined Shewhart-CUSUM control chartmethodology for intrawell comparison of analyteconcentrations over time and does not require anupgradient well. A case study from the U.S.Department of Energy's Hanford Site is used forillustration purposes. This method is broadlyapplicable in groundwater monitoring programs wherethere is no clearly defined upgradient location, thegroundwater flow rate is exceptionally slow, or wherea high degree of spatial variability exists inparameter concentrations. This study also indicatesthat the use of the Data Quality Objectives (DQO)process can assist in designing an efficient andcost-effective groundwater monitoring plan to achievethe optimum goal of both low false positive and lowfalse negative rates (high power).  相似文献   
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Big cities are often said to have big water problems, and Shanghai is no exception. In this paper, we examine and compare the influence of the major factors that give rise to the risk of water insecurity in Shanghai. There is an extensive and diverse literature on these issues, dealt with in isolation, and here, we provide a synthesis of the literature, together with our own assessments and calculations, to assess what are the risks to Shanghai’s water supply and what is our degree of confidence in this assessment. We describe the systems that supply water to the city, and past and future changes in the systems, including changes in the glaciers that supply some water to the river, changes in climate, changes in land use, the construction of dams, and water diversions. We show how, at the same time as Shanghai is increasing its dependence on the Yangtze river, water diversions and sea level rise are increasing the risk that this water will be too saline to consume at certain times of the year. This analysis suggests that most of the major drivers of the risk to water security in Shanghai are within the power of environmental managers to control.  相似文献   
4.
Using structural equations, we estimated the relationship between employees' experiences of seven job conditions, that have been identified as potential job stressors, and psychological distress in a random sample of 504 full-time employed men and women in dual-earner couples. The seven job conditions were: skill discretion, decision authority, schedule control, job demands, pay adequacy, job security, and relations with supervisor. We found that two job conditions — skill discretion and job demands — were related to psychological distress, whereas five other conditions were not. These findings lend partial support to Karasek's job demand — job control model. In our analysis, skill discretion, one of the two components of job control (referred to jointly as decision latitude) was related to distress, however, decision authority, the second component, was not. A third aspect of control, schedule control, was also unrelated to distress. For full-time employed women and men in dual-earner couples, the additive effects of feeling concerned about having to do dull, monotonous work and having to work under pressure of time and conflicting demands were associated with psychological distress. Finally, the magnitude of the relationships between these job experiences and psychological distress did not differ between men and women.  相似文献   
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Barry J. Barnett 《Disasters》1999,23(2):139-155
Governments often provide grants or low-interest loans to disaster victims. Yet these programmes have proven to be quite costly. In addition, questions have been raised about associated behavioural incentives. Conceptually, government disaster insurance programmes should be more efficient, consistent and equitable than ex post facto disaster relief in the form of grants and loans. Yet the performance of government disaster insurance programmes has been mixed, at best. This article reviews the history of US federal natural disaster assistance to individuals and concludes with a recommendation for a new government role in the provision of disaster insurance.  相似文献   
6.
The application of the critical loads methodology for radioactive contamination of Arctic and sub-arctic ecosystems, where natural and semi-natural food products are important components of the diet of many people, is proposed and discussed. The critical load is herein defined as the amount of radionuclide deposition necessary to produce radionuclide activity concentrations in food products exceeding intervention limits. The high transfer of radiocaesium to reindeer meat gives this product the lowest critical load, even though the intervention limit is relatively high compared with other products. Ecological half-lives of radiocaesium in natural and semi-natural products are often very long, and it is therefore important to take account of contamination already present in the event of an accident affecting areas where such products are important. In particular, the long ecological half-life for radiocaesium in moose meat means that the critical load is highly sensitive to prior deposition. An example of the potential application of the method for emergency preparedness is given for the Chernobyl accident.  相似文献   
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Cyclodextrin‐enhanced flushing of contaminants from the subsurface is a promising innovative remediation technology. It will become more economically viable at more sites if methods can be developed to recover and reconcentrate the cyclodextrin solution after it has been flushed through an aquifer. The goal of this study was to determine if membrane technology is capable of meeting that need. Five membranes with different material properties were tested for this purpose in the laboratory. The results of these tests indicate that there are large differences both in the efficiency of these membranes to extract hydroxpropyl‐β‐cyclodextrin (HPCD) and their stability when exposed to trichloroethylene (TCE) at concentrations near aqueous solubility. Not only does the molecular weigh cutoff (MWCO) of a membrane determine if HPCD can be retained, but crucial selection criteria are the membrane's resistance and compatibility with TCE. Of the five membrane materials tested, only two (polymer composite membrane and polysulfone) met both these requirements. The polymer composite membrane (MPF‐44) showed reliable and stable HPCD recoveries (>95 percent) even when exposed to high TCE concentrations. The polysulfone membrane showed high HPCD recoveries, 88.5 ± 0.4 percent to 97 percent ±1 percent for ultrafiltration and nanofiltration membranes, respectively. However, membrane swelling and deterioration became a problem at high TCE concentrations (>1,000 mg/L). These problems diminished when the TCE concentration was less than 1 mg/L. Field tests demonstrated that batch mode treatment by ultrafiltration doubled the cyclodextrin concentration from 5 to 10 percent within three hours at a constant operating pressure of 13 psi. Under continuous single‐pass treatment conditions, cyclodextrin concentration also increased, although the rate of increase was much smaller than in batch mode. Overall, these tests showed that cyclodextrin recovery is possible under field conditions. © 2007 Wiley Periodicals, Inc.  相似文献   
8.
旅游业关注组织 ( Tourism Concern) 意识到在必然的旅游程序中 , 存在着一连串错误的解释 , 它们都在暗示自己才是旅游开发所产生问题的解决方案 . 就我们所见 , 它们被冠以的名目 有 : “ 责任心之旅 “ 、 “ 绿色之旅 “ 、 “ 亲近贫困之旅 “ 、 “ 民俗特色之旅 “ 、 “ 社区之旅 “ 、 “ 生态之旅 “ 等等 , 不一而足 . 它们把我们的视线从关注真正的需求 , 切换到旅游结构 与发展中基本原则的改变 .   ……  相似文献   
9.
A spatially implemented model designed to assist the identification of optimal countermeasure strategies for radioactively contaminated regions is described. Collective and individual ingestion doses for people within the affected area are estimated together with collective exported ingestion dose. A range of countermeasures are incorporated within the model, and environmental restrictions have been included as appropriate. The model evaluates the effectiveness of a given combination of countermeasures through a cost function which balances the benefit obtained through the reduction in dose with the cost of implementation. The optimal countermeasure strategy is the combination of individual countermeasures (and when and where they are implemented) which gives the lowest value of the cost function. The model outputs should not be considered as definitive solutions, rather as interactive inputs to the decision making process. As a demonstration the model has been applied to a hypothetical scenario in Cumbria (UK). This scenario considered a published nuclear power plant accident scenario with a total deposition of 1.7x10(14), 1.2x10(13), 2.8x10(10) and 5.3x10(9)Bq for Cs-137, Sr-90, Pu-239/240 and Am-241, respectively. The model predicts that if no remediation measures were implemented the resulting collective dose would be approximately 36 000 person-Sv (predominantly from 137Cs) over a 10-year period post-deposition. The optimal countermeasure strategy is predicted to avert approximately 33 000 person-Sv at a cost of approximately 160 million pounds. The optimal strategy comprises a mixture of ploughing, AFCF (ammonium-ferric hexacyano-ferrate) administration, potassium fertiliser application, clean feeding of livestock and food restrictions. The model recommends specific areas within the contaminated area and time periods where these measures should be implemented.  相似文献   
10.
生态毒理学中的一个重要问题是污染物暴露对生理功能和健康的长期影响程度。已有系列研究探讨了美国红隼摄入第二代抗凝血灭鼠剂(AR)溴鼠灵(BROD)的环境浓度。以0.3、1.0或3.0 μg BROD/g(wt)喂养7天后,红隼表现出剂量依赖性出血、组织病理学损伤和凝血病变(凝血酶原延长和罗素毒液组)。在终止为期7天的0.5 μg BROD/g饮食的暴露后,延长的凝血时间在一周内恢复到基线值,但肝和肾中的BROD残留(最终半衰期估计值>50天)在28天的恢复期内持续存在。为了检测连续性AR暴露的危险性,红隼连续暴露于第一代AR—氯鸟嘌呤(CPN;每日饮食1.5 μg/g)或第二代AR—BROD(每日饮食0.5 μg/g)中7天,在恢复期后,用低剂量CPN(每日饮食0.75 μg/g)暴露7天。与对照组和CPN处理组的红隼相比,后续暴露明显延长了BROD处理组的凝血酶原时间。这些数据表明,第二代AR—BROD可能具有长期影响,增加了随后AR暴露的毒性。自由放养的捕食性和食腐性野生动物经常反复暴露于AR中,在进行危害和风险评估时需要考虑到这种长期的毒理学效应。  相似文献   
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