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161.
Higher-tier environmental risk assessments on “down-the-drain” chemicals in river networks can be conducted using models such as GREAT-ER (Geography-referenced Regional Exposure Assessment Tool for European Rivers). It is important these models are evaluated and their sensitivities to input variables understood. This study had two primary objectives: evaluate GREAT-ER model performance, comparing simulated modelled predictions for LAS (linear alkylbenzene sulphonate) with measured concentrations, for four rivers in the UK, and investigate model sensitivity to input variables. We demonstrate that the GREAT-ER model is very sensitive to variability in river discharges. However it is insensitive to the form of distributions used to describe chemical usage and removal rate in sewage treatment plants (STPs). It is concluded that more effort should be directed towards improving empirical estimates of effluent load and reducing uncertainty associated with usage and removal rates in STPs. Simulations could be improved by incorporating the effect of river depth on dissipation rates.  相似文献   
162.
Vehicle collisions with wildlife have the potential to negatively impact species everywhere roads divide natural habitats; this is especially true in areas where roads are a recent addition to the landscape (e.g., in the last decade) and/or where expansion of a road network is underway. This study addresses the impact of traffic fatalities on lava lizards, Microlophus albemarlensis, on the island of Santa Cruz, Galápagos. The main road bisecting the island north to south was added to the island beginning in 1974 but not fully paved until 2000. We assessed impacts occurring due to traffic and vehicle speeds on the island. This study adds impacts to lizard populations to those conducted on birds on Santa Cruz, providing a means to create multi-species recommendations. To quantify impacts to lizard populations, we assessed lizards on randomly chosen transects perpendicular to the road. We used Poisson regression to analyze those data and found a 30% increase in lizard abundance per 100 m distance from the road across vegetation zones. We compared incidence of prior tail loss of road-killed lizards and live animals to comment on additional energetic costs of occupying near-road territories. Tail condition could not be assessed in some road-killed lizards; among those that we could assess, 29% showed evidence of prior tail loss. That rate declined to apparent baseline conditions of only 1% beyond 200 m from the road. By traveling the length of the 40-km road, we identified hot spots for fatalities of both lizards and birds to provide necessary information for developing management and remediation strategies. We offer guidance on Best Management Practices, such as testing overpasses, fencing and underpasses, which might reduce vehicle impacts to lizards from drivers on the current road. This information is essential because of a planned increase in the Santa Cruz road network in areas where lava lizards are most abundant.  相似文献   
163.
Chlorinated phenols are used at many saw mills for impregnation of saw timber. Waste products containing the used compound follow this process. Tests have been performed on pilot and full-scale in order to investigate the possibility of destroying these wastes by combustion.The pilot scale tests with 70 g of pentachlorophenol show that at a transit time of approximately 3 seconds and a combustion temperature of 600°C the unburnt residue was 50 mg/kg fed in pentachlorophenol. At 800°C the residue decreased to 15 mg/kg. No formation of octachlorodioxin could be proved.The full-scale test with a small amount of pentachlorophenol and a large amount of tetrachlorophenol show that at a transit time of approximately 0.9 seconds and a temperature varying during one test between 620–875° (average 760°C), the unburnt residue was 9 mg/kg for tetrachlorophenol and 650 mg/kg for pentachlorophenol. At an increased load the residue increased gradually, being 5.900 mg/kg for tetrachlorophenol and 7.100 mg/kg for pentachlorophenol at a test when the temperature was varied between 460 and 850° (average 620°C). Analyses of chlorinated dioxins show that octachlorodioxin was found in the flue gas at one of the tests. This may indicate a formation.  相似文献   
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Norovirus outbreaks are associated with the consumption of contaminated shellfish, and so efficient methods to recover and detect infectious norovirus in shellfish are important. The Proteinase K digestion method used to recover norovirus from shellfish, as described in the ISO 15216, would be a good candidate but its impact on the virus capsid integrity and thus infectivity was never examined. The aim of this study was to assess the impact of the Proteinase K digestion method, and of the heat treatment component of the method alone, on norovirus (genogroups I and II) and MS2 bacteriophage capsid integrity. A slightly modified version of the ISO method was used. RT-qPCR was used for virus detection following digestion of accessible viral RNA using RNases. MS2 phage infectivity was measured using a plaque assay. The effect of shellfish digestive glands (DG) on recovery was evaluated. In the presence of shellfish DG, a reduction in MS2 phage infectivity of about 1 log10 was observed after the Proteinase K digestion method and after heat treatment component alone. For norovirus GII and MS2 phage, there was no significant loss of genome following the Proteinase K digestion method but there was a significant 0.24 log10 loss of norovirus GI. In the absence of shellfish DG, the reduction in MS2 phage infectivity was about 2 log10, with the addition of RNases resulting in a significant loss of genome for all tested viruses following complete Proteinase K digestion method and the heat treatment alone. While some protective effect from the shellfish DG on viruses was observed, the impact on capsid integrity and infectivity suggests that this method, while suitable for norovirus genome detection, may not completely preserve virus infectivity.  相似文献   
167.
A National Swedish Environmental Monitoring Programme, the PMK, has been designed for regular and permanent recording of environmental conditions and long-term changes in background regions, and for keeping track of the flux of pollutants in and between various media. Many of the projects involved deal with integrated monitoring of terrestrial and limnic ecosystems. This work is carried out in or near some 20 small watersheds, usually selected in national parks or nature reserves. The environmental factors monitored in these areas include concentrations of chemical substances in precipitation, soil, groundwater, surface water, and organisms, as well as biological parameters—such as the population size and reproductive capacity of certain species—that may indicate effects of environmental disturbances. The data from this programme can be used as a reference to environmental data acquired near pollution sources, and as a basis for measures against e.g. acid rain, heavy-metal pollution, and use of pesticides. The biological parameters may also reveal effects of yet unknown pollutants or other disturbances.  相似文献   
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Environmental manipulation experiments showed that species respond individualistically to each environmental-change variable. The greatest responses of plants were generally to nutrient, particularly nitrogen, addition. Summer warming experiments showed that woody plant responses were dominant and that mosses and lichens became less abundant. Responses to warming were controlled by moisture availability and snow cover. Many invertebrates increased population growth in response to summer warming, as long as desiccation was not induced. CO2 and UV-B enrichment experiments showed that plant and animal responses were small. However, some microorganisms and species of fungi were sensitive to increased UV-B and some intensive mutagenic actions could, perhaps, lead to unexpected epidemic outbreaks. Tundra soil heating, CO2 enrichment and amendment with mineral nutrients generally accelerated microbial activity. Algae are likely to dominate cyanobacteria in milder climates. Expected increases in winter freeze-thaw cycles leading to ice-crust formation are likely to severely reduce winter survival rate and disrupt the population dynamics of many terrestrial animals. A deeper snow cover is likely to restrict access to winter pastures by reindeer/caribou and their ability to flee from predators while any earlier onset of the snow-free period is likely to stimulate increased plant growth. Initial species responses to climate change might occur at the sub-species level: an Arctic plant or animal species with high genetic/racial diversity has proved an ability to adapt to different environmental conditions in the past and is likely to do so also in the future. Indigenous knowledge, air photographs, satellite images and monitoring show that changes in the distributions of some species are already occurring: Arctic vegetation is becoming more shrubby and more productive, there have been recent changes in the ranges of caribou, and "new" species of insects and birds previously associated with areas south of the treeline have been recorded. In contrast, almost all Arctic breeding bird species are declining and models predict further quite dramatic reductions of the populations of tundra birds due to warming. Species-climate response surface models predict potential future ranges of current Arctic species that are often markedly reduced and displaced northwards in response to warming. In contrast, invertebrates and microorganisms are very likely to quickly expand their ranges northwards into the Arctic.  相似文献   
170.
本文讨论了有关能源的思想观念的演变.20年前当几位作者开始携手合作研究能源时,人们一般是以发展的眼光、从供应方的角度来考虑能源问题,将注意力集中到消费趋势以及如何扩大供给以满足不断增长的需求上.这种方法在能源利用的环境影响、安全性和公平合理性方面的研究局限深深地困扰着他们.例如,大约有20亿人口经济条件有限,买不起现代能源,这严重限制了他们生活水平的提高.此外,能源还是造成环境问题的重要因素,其中包括室内空气污染、城市空气污染、酸化和全球气候变暧等.笔者认为,应当树立新的能源供给观念,使能源的供给方式有助于解决这些严重问题.笔者主张,能源必须成为推进可持续发展——经济上可行、以需要为导向、自力更生的能及无损于环境的发展——的工具,而且,应当将研究重点放在能源的终端用途上和能源供应的服务上.有助于实现可持续发展目标的能源技术方案也在本文进行了讨论.文中强调了制订和运用新型能源技术解决方案的必要性.笔者以巴西乙醇的利用为例,阐述了使发展中国家避免重复工业化国家所犯错误而在技术上实现跨越式发展的可能性.文中还重点介绍了在发展中国家引进先进技术过程中外国直接投资可能起到的作用,阐述了农村能源的近期和远期战略.最后,介绍了促进能源系统的发展,使之与可持续发展的步调一致并且支持可持续发展的相关政策.  相似文献   
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