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991.
Thallium in the hydrosphere of south west England   总被引:1,自引:0,他引:1  
Thallium is a highly toxic metal whose environmental concentrations, distributions and behaviour are not well understood. In the present study we measure the concentrations of Tl in filtered and unfiltered samples of rain, tap, river, estuarine and waste waters collected from south west England. Dissolved Tl was lowest (<20 ng L−1) in tap water, rain water, treated sewage and landfill effluents, estuarine waters, and rivers draining catchments of sandstones and shales. Concentrations up to about 450 ng L−1 were observed in rivers whose catchments are partly mineralized and where metal mining was historically important, and the highest concentration (∼1400 ng L−1) was measured in water abstracted directly from an abandoned mine. Compared with other trace metals measured (e.g. As, Cd, Co, Cr, Cu, Ni, Pb, Zn), Tl has a low affinity for suspended particles and undergoes little removal by conventional (hydroxide precipitation) treatment of mine water.  相似文献   
992.
The occurrence of free and conjugated estrogens was examined in a survey of eleven sewage treatment plants (STPs) and their discharge water in the United Kingdom using grab sampling. The STPs included trickling filter with and without tertiary treatment, and activated sludge with tertiary treatment. For three activated sludge plants both influent and effluent samples were compared. For a further 8 STPs only the effluent was examined. The estrone-3-sulphate, estradiol-3-sulphate and estriol-3-sulphate concentrations (up to 20 ng L−1) were typically 5-fold that of the respective free estrogen concentration in the effluents. This represents a substantial additional ‘potential’ estrogen load arriving in the receiving waters. Estrone-3-glucuronide was found at 9 ng L−1, estradiol-3-glucuronide at 7 ng L−1, and estriol-3-glucuronide at 32 ng L−1 in sewage influent. Except on one occasion, no glucuronide conjugates could be found in the effluent. The results suggest in most cases glucuronide conjugates will be completely transformed in sewage treatment whilst sulphate conjugates will only be partially removed.  相似文献   
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995.
In what circumstances do organizations react to changes in their operating environment by adopting proportionate policy responses? And drawing on institutional theory, what expectations can we formulate in relation to the proportionality of policy responses to climate change? These two research questions frame this article, which seeks to make new connections between the emerging perspective of proportionality in policy-making and existing institutional theories. We find that institutional theories are well suited to formulating expectations concerning the (dis)proportionality of policy responses, but their explanatory power can be further improved by taking the characteristics of specific climate policy problems into account. While there are many different problems nested in the ‘meta’ problem of climate change, we find that most of them have characteristics which suggest that policy under-reactions are more, not less likely. Amongst institutional theories, rational choice institutionalism provides the clearest expectation that proportionate policy responses are unlikely. Policy entrepreneurship is identified as one obvious way in which to stimulate proportionate policy responses, through fostering new ways of thinking within organizations.  相似文献   
996.
Moore, Johnnie N., Alicia S. Arrigoni, and Andrew C. Wilcox, 2012. Impacts of Dams on Flow Regimes in Three Headwater Subbasins of the Columbia River Basin, United States. Journal of the American Water Resources Association (JAWRA) 48(5): 925‐938. DOI: 10.1111/j.1752‐1688.2012.00660.x Abstract: We compared long‐term changes in flow regimes resulting from climate change with those resulting from dams in three matched pairs of natural and modified headwater subbasins of the Columbia River. Based on the analysis of 12 flow‐regime metrics, we found that damming had minimal effect on most quantity of flow metrics, but major effect on timing of flow metrics, especially those representing “spring runoff.” In all modified subbasins, “spring runoff” metrics occurred much earlier than natural flow (up to ~44 days earlier for April‐July flows). Storage capacity modulated the magnitude of timing of flow‐metric changes, with the largest storage capacity leading to the most change. However, even in subbasins with low storage capacity, we found significant change in most timing of flow metrics. We also found that damming, especially in subbasins with higher storage capacity, overwhelmed climate variability in all basins for most flow metrics. This shows that reservoir operations need to be modified to more closely match the natural timing of flow regimes to promote positive ecologic response in modified rivers, even in basins where quantity of flow metrics have not changed substantially as a result of damming.  相似文献   
997.
Extensive surveys of sediment burdens of radiocaesium, specifically 137Cs, and other radioactive contaminants in the Arctic during the 1990's, indicate that almost all anthropogenic radionuclides buried on continental shelves adjacent to Alaska are derived from global bomb fallout. the 137Cs (half-life: 30.2y) activities observed in surface (0-4 cm) marine sediments however, vary widely, albeit much less than the expected current inventory resulting from bomb fallout at this latitude (∼100mBq cm-2). This observed geographical variation provided the opportunity to evaluate physical and biological mechanisms that may affect caesium biogeochemistry on Arctic continental shelves. We investigated whether high biological productivity in portions of the Bering and Chukchi Seas is effective in removing dissolved radiocaesium from the water column, and whether biological production in overlying water affects total radiocaesium inventories in sediments. Based upon C/N ratios in the organic fraction of shallow sediments, we found no evidence that higher inventories or surface activities of radiocaesium are present in areas with higher deposition of particulate organic matter. Based upon stable carbon isotope ratios of organic matter in sediments, we found no evidence that terrestrial runoff contributes proportionally to higher surface activities, although terrestrial runoff may affect total inventories of the radionuclide. Radiocaesium content of surface sediments was significantly correlated with total organic carbon content of sediments and the proportion of sediments in the finest sediment fractions. Because high current flow can also be expected to influence distributions of those sedimentary parameters, we conclude that re-distribution of  相似文献   
998.
The appraisal of sustainability: Some problems and possible responses   总被引:1,自引:0,他引:1  
The development of 'indicators' and associated techniques for the appraisal of 'sustainability' requires efforts to systematically define, quantify and aggregate many disparate dimensions of social, environmental and economic performance. This necessarily raises a number of serious theoretical and methodological difficulties, including those relating to the selection and framing of 'problems' and 'options', the treatment of deep uncertainties and the 'impossibility' of aggregating in analysis the divergent social interests and value judgements which govern the prioritisation of the different dimensions of 'sustainability'. After exploring the depth and scope of some of these difficulties, this paper argues that they render futile any attempt to develop an 'analytical fix' for the problems of appraisal. In this light, systematic public participation is recognised not just as an issue of political efficacy and legitimacy, but also as a fundamental matter of analytical rigour. However, it is also concluded that once aspirations to the 'analytical fix' are renounced, there is much that might be contributed by transparent, straightforward quantitative analytical tools and the paper ends with some recommendations and an example in this regard.  相似文献   
999.
1000.

Introduction

Young male drivers are over-represented in traffic accidents; they were involved in 14% of fatal accidents from 1991 to 2003 while holding only 8% of all drivers licenses in the UK. In this study, a subset of the UK national road accident data from 1991 to 2003 has been analyzed. The primary aim is to determine how to best use monetary and progressive resources to understand how road safety measures will reduce the severity of accidents involving young male drivers in both London and Great Britain.

Method

Ordered probit models were used to identify specific accident characteristics that increase the likelihood of one of three categorical outcomes of accident severity: slight, serious, or fatal.

Results

Characteristics found to lead to a higher likelihood of serious and fatal injuries are generally similar across Great Britain and London but are different from those predicted to lead to a higher likelihood of slight injuries. Those characteristics predicted to lead to serious and fatal injuries include driving in darkness, between Friday and Sunday, on roads with a speed limit of 60 mph, on single carriageways, overtaking, skidding, hitting an object off the carriageway, and when passing the site of a previous accident. Characteristics predicted to lead to slight injuries include driving in daylight, between Monday and Thursday, on roads with a speed limit of 30 mph or less, at a roundabout, waiting to move, and when an animal is on the carriageway.

Impact on Industry

These results aid the selection of policy options that are most likely to reduce the severity of accidents involving young male drivers.  相似文献   
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