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In the context of integrated assessment, the authors address the issue of uncertainty and subjectivity in modelling. In relating bias to different perspectives, the authors introduce the methodology of multiple model routes, which are reflections of different perceptions of reality and various policy preferences. As heuristic they use three perspectives, which are distinguished in cultural theory. The article describes case-studies on the population and health controversy in order to illustrate the possibilities of their approach. The article concludes with discussing the lessons learned by applying this methodology.  相似文献   

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We compared levels of eight heavy metals in common tern eggs collected in 1982 (n=24) from coastal New Jersey with archived specimens collected from the same colonies in 1971 (N=9). Levels of all metals, except cobalt, showed a significant decrease over the 11 year period, with lead and nickel showing the greatest decline. Mercury levels declined over 50% based on geometric means. Cadmium and mercury showed the lowest levels in both years. Pair-wise correlation coefficients on log-transformed data revealed lower correlations in 1971, whereas most metal pairs showed significant correlations in 1982. Mercury levels showed significant positive correlations with cobalt, cadmium, and nickel in 1971, but were not correlated with levels of any other metal in 1982.  相似文献   

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Public participation is considered a distinguished feature of Strategic Environmental Assessment (SEA), and the SEA literature has traditionally identified several benefits attached to it, from more open and transparent decision-making to greater acceptance of plans/programmes' output by the affected population. However, relatively little empirical evidence has been collected so far on the extent and outcomes of public engagement as it is being carried out in current SEA practice. In this article, we present the results of a study on this theme based on a direct survey of 47 SEA practitioners and scholars from different countries. Respondents were asked to report their experience about a number of items including: the frequency of SEA process featuring deep public participation; its overall influence on plan/programmme-making; the identification of the main factors impeding it; the correlation of public involvement with environmental outcomes; and the increase of costs. Results indicate that public engagement in current SEA practice is still relatively limited and with limited influence on decision-making. The main impeding factors seem to be: lack of political willingness by proponents; insufficient information on the SEA process by the public; and weakness of the legal frames. However, respondents also report that when effective public engagement takes place, benefits do arise and identify a positive correlation between the degree of public involvement and the environmental performance of plans and programmes. Overall, findings suggest that public involvement has indeed the potential to positively influence both SEA and decision-making, although this should be supported from the policy side by stronger legal frames, higher requirements and improved technical guidance.  相似文献   

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综述了近年来国内外学者对大气气溶胶中痕量金属元素的研究进展,介绍了痕量金属元素的地球化学行为,以及大气气溶胶中痕量金属的源解析方法、在环境中的循环与污染、生物有效性及对人体的健康效应。建议研发更可靠的分析方法或在线检测仪器,避免采样和样品前处理过程中痕量金属的污染和损失;建立监测网络,形成区域性的大气监测模式,更全面地分析污染来源;与监测超级站建设、空气污染流行病学设计和毒性机制研究相结合,建立更加完善的研究体系。  相似文献   

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For decades there has been an intense interest in the toxic effects of trace metals on biological organisms in the environment. This period of time has seen increasing improvements in analytical techniques for the measurement and study of trace metals and their subsequent application to a broad spectrum of water systems around the globe. This work has included studies of the geographical distributions of trace metals in different water types in the ocean, the modes of transport and uptake of trace metals and the study of historical changes in trace metal accumulation. Early research highlighted strong similarities in the behaviours of many trace metals and those of well-understood chemical nutrients such as phosphate, nitrate and silicate, known to be essential for phytoplankton growth in the ocean. This suggests that phytoplankton regulate the trace metal composition of seawater for their own benefit. A major achievement in this regard has been the ability to measure, at the sub-nmol/L level, trace metal species that are complexed by naturally-occurring organic ligands of biological origin in ocean waters. It is now clear that the free ion activities of many essential and/or toxic trace metals are regulated by highly specific, strongly complexing ligands exuded by marine phytoplankton. This research encourages a new paradigm in which the growth rates and species composition of primary marine organisms are affected by trace metals at concentration levels orders of magnitude lower than is conventionally believed. As a consequence, the capacity of natural waters to assimilate trace metal-contaminants may be correspondingly much lower than is currently thought reasonable.  相似文献   

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Ships have been identified as one of the important vectors in the translocation of organisms from one bioregion to another leading to bioinvasion. In this context, harbours serve as a gateway for the introduction of alien species. Surveys were carried out in the vicinity of ports of Mumbai for macrobenthic fauna, zooplankton and hard substratum community on three different occasions during 2001–2002. The study shows that 14 polychaete species are recently introduced to this area. Mytilopsis sallei, a bivalve, which is an invasive species in the Indian context continued to be present but was restricted to enclosed docks, indicating preference for embayed water bodies. The polychaete Protula tubularia was abundant in the hard substratum community and is being reported as a possible ship-mediated introduction.  相似文献   

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生物炭在土壤中的老化及其吸附重金属的研究进展   总被引:1,自引:0,他引:1  
综述了生物炭在土壤中的老化机制及主要影响因素方面的研究进展,指出生物炭的理化性质和结构表征在土壤中发生变化是其老化机制,生物炭的特性、土壤特性和环境条件等因素共同影响着生物炭的老化。总结了老化生物炭在土壤中对重金属吸附的影响,生物炭在老化过程中理化性质和结构表征的变化影响了生物炭-土壤体系对重金属的吸附,并且吸附能力因老化方式和重金属不同而存在差异。提出了开展多种重金属共存条件下老化生物炭的吸附效果和机理研究、针对生物炭田间实际老化过程对土壤重金属的吸附行为开展季节性和多年长期观测研究,以及对生物炭修复的重金属污染土壤在生物炭老化过程中可能造成的环境和健康风险开展综合、长期的跟踪研究与评估等展望。  相似文献   

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Relatively little is known about contaminants in reptiles, particularly turtles. The distribution of metals in eggs, liverand muscle of diamondback terrapin (Malaclemys terrapin) was examined from Barnegat Bay, New Jersey as part of an aquatic study to understand movement of contaminants in the bay. Lead and cadmium were relatively low in all tissues. There were significant differences among tissues for all metals, except lead. Where there were significant differences, levels werehighest in the liver, except for chromium. Levels of mercurywere 6.6 times higher in the liver than muscle, and manganeselevels were 4 times as high. The levels of metals in muscle ofdiamondback terrapin are below those that might cause effects inconsumers, including humans who eat them in stews. However, thelevel of mercury in liver is sufficiently high to be problematicfor consumers and scavengers that eat liver.  相似文献   

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土壤重金属元素检测国际实验室比对研究   总被引:1,自引:0,他引:1  
IERM和CNAS合作组织开展了亚太实验室合作组织(APLAC)能力验证计划"APLAC T066土壤重金属元素检测",其目的是评价参加实验室定量分析土壤重金属元素总量的能力。研究所用的能力验证样品为IERM研制的土壤标准样品。结果表明,参加实验室检测土壤砷、铜、汞、镍、铅和锌的结果满意率分别为85.7%、95.8%、77.1%、83.3%、93.5%和91.7%。样品消解过程加入氢氟酸时,铅和锌的检测结果与标准值更加接近,说明检测土壤重金属元素总量时氢氟酸的加入非常关键。文章还对比对实验室结果评价的统计方法进行了探讨。  相似文献   

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Heavy Metals Fractionation in Ganga River Sediments, India   总被引:2,自引:0,他引:2  
The Ganga River is the largest river in India which, originates in the Himalayas and along with the Brahmaputra River, another Himalayan river, transports enormous amounts of sediments from the Indian sub-continent to the Bay of Bengal. Because of the important role of river sediments in the biogeochemical cycling of elements, the Ganga river sediments, collected from its origin to the down stretches, were studied in the present context, to assess the heavy metals associated with different chemical fractions of sediments. The fractionation of metals were studied in the sediments using SM&T protocol for the extraction of heavy metals and geo-accumulation index (GAI) (Muller, Schwermetalle in den sedimenten des rheins – Veranderungen seit. Umschau, 79, 778–783, 1979) and Metal Enrichment Factor (MEF) in different fractions were calculated. As with many river systems, residual fractions constitute more than 60% of total metals, except Zn, Cu and Cr. However, the reducible and organic and sulfide components also act as major sinks for metals in the down stretches of the river, which is supported by the high GAI and MEF values. The GAI values range between 4 and 5 and MEF exceed more than 20 for almost all the locations in the downstream locations indicating to the addition of metals through urban and industrial effluents, as compared to the low metals concentrations with less GAI and MEF in the pristine river sediments from the rivers in Himalayas.  相似文献   

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Project-level impact assessment was originally conceived as a snapshot taken in advance of project implementation, contrasting current conditions with a likely future scenario involving a variety of predicted impacts. Current best practice guidance has encouraged a shift towards longitudinal assessments from the pre-project stage through the implementation and operating phases. Experience and study show, however, that assessment of infrastructure-intensive projects rarely endures past the project's construction phase. Negative consequences for environmental, social and health outcomes have been documented. Such consequences clarify the pressing need for longitudinal assessment in each of these domains, with human rights impact assessment (HRIA) as an umbrella over, and critical augmentation of, environmental, social and health assessments. Project impacts on human rights are more closely linked to political, economic and other factors beyond immediate effects of a company's policy and action throughout the project lifecycle. Delineating these processes requires an adequate framework, with strategies for collecting longitudinal data, protocols that provide core information for impact assessment and guidance for adaptive mitigation strategies as project-related effects change over time. This article presents general principles for the design and implementation of sustained, longitudinal HRIA, based on experience assessing and responding to human rights impact in a uranium mining project in Malawi. The case study demonstrates the value of longitudinal assessment both for limiting corporate risk and improving human welfare.  相似文献   

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