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791.
The International Joint Commission's Water Quality Board has identified 42 Areas of Concern in the Great Lakes ecosystem where Great Lakes Water Quality Agreement objectives or jurisdictional standards, criteria or guidelines, established to protect uses, have been exceeded and remedial actions are necessary to restore beneficial uses. As a result of the 1985 report of the Water Quality Board, the eight Great Lakes states and the Province of Ontario committed themselves to developing a remedial action plan (RAP) to restore all uses in each Area of Concern within their political boundaries. Each RAP must identify the specific measures necessary to control existing sources of pollution, abate existing contamination (e.g., contaminated sediments), and restore all beneficial uses. Points which must be explicitly addressed in each RAP include: geographic extent of problem, beneficial uses impaired, causes of problems, remedial measures and a schedule for implementation, responsible agencies, and surveillance and monitoring activities that will be used to track effectiveness of remedial actions. The jurisdictions are responsible for developing RAPs, and the International Joint Commission is responsible for evaluating the adequacy of each RAP and tracking progress in restoring beneficial uses. 相似文献
792.
793.
Michael D. Waters Vincent F. Simmon Ruby Valencia Ann D. Mitchell Ted A. Jorgenson 《Journal of environmental science and health. Part. B》2013,48(6):867-906
Abstract In the last few years, marked progress has been made in the development of methods for evaluating the mutagenic and carcinogenic potential of pesticide chemicals. The correlation of genetic and related biological activity in short‐term tests with carcinogenic activity in whole animals allows the utilization of short‐term mutagenicity bioassays to prescreen chemicals for effects related to mutation induction and presumptive carcinogenicity. In addition, bioassays now available can measure directly the chemical transformation of normal cells in culture into cells capable of producing tumors when injected into animals. This paper will review briefly the major types of relevant short‐term tests and will develop a rationale for a phased approach to the evaluation of the mutagenic and carcinogenic potential of environmental chemicals. This approach involves the sequential application of bioassays which are organized into a three‐level matrix emphasizing first detection, then confirmation, and finally hazard assessment. Chemicals demonstrating positive results in the short‐term detection systems and confirmatory bioassays are pursued in higher level whole animal tests. A core battery of tests is proposed to operationally define a negative result. The phased approach should facilitate a cost effective utilization of limited testing resources and provide protection for human health in proportion to the anticipated hazard. Results obtained in evaluating a series of thirty‐eight pesticide chemicals according to the phased approach are discussed in detail. 相似文献
794.
Pinning down vulnerability: from narratives to numbers 总被引:2,自引:0,他引:2
Social vulnerability analyses have typically relied upon narratives to capture the nuances of the concept. While narratives have enhanced our understanding of the multiple drivers of vulnerability, they have had limited influence on hazards and climate adaptation policy. This is partially a function of the different needs and goals of the policy and research communities. The former prioritises generalised quantitative information, while the latter is more concerned with capturing complexity. A theoretically driven and empirically tested quantitative vulnerability and capacities index (VCI) for use at the local scale is presented to help connect vulnerability research and policy. There are four versions of the index for use in rural and urban contexts at the household and community levels. There can be an infinite number of drivers of vulnerability, but the VCI draws upon 12 indicators to represent material, institutional and attitudinal aspects of differential vulnerability and capacities. 相似文献
795.
Artificial propagation strategies often incur selection in captivity that leads to traits that are maladaptive in the wild. For propagation programs focused on production rather than demographic contribution to wild populations, effects on wild populations can occur through unintentional escapement or the need to release individuals into natural environments for part of their life cycle. In this case, 2 alternative management strategies might reduce unintended fitness consequences on natural populations: (1) reduce selection in captivity as much as possible to reduce fitness load (keep them similar), or (2) breed a separate population to reduce captive‐wild interactions as much as possible (make them different). We quantitatively evaluate these 2 strategies with a coupled demographic–genetic model based on Pacific salmon hatcheries that incorporates a variety of relevant processes and dynamics: selection in the hatchery relative to the wild, assortative mating based on the trait under selection, and different life cycle arrangements in terms of hatchery release, density dependence, natural selection, and reproduction. Model results indicate that, if natural selection only occurs between reproduction and captive release, the similar strategy performs better. However, if natural selection occurs between captive release and reproduction, the different and similar strategies present viable alternatives to reducing unintended fitness consequences because of the greater opportunity to purge maladaptive individuals. In this case, the appropriate approach depends on the feasibility of each strategy and the demographic goal (e.g., increasing natural abundance, or ensuring that a high proportion of natural spawners are naturally produced). In addition, the fitness effects of hatchery release are much greater if hatchery release occurs before (vs. after) density‐dependent interactions. Given the logistical challenges to achieving both the similar and different strategies, evaluation of not just the preferred strategy but also the consequences of failing to achieve the desired target is critical. Evaluación de Estrategias Alternativas para Minimizar las Consecuencias No Inesperadas en la Adecuación de Individuos Criados en Cautiverio sobre Poblaciones Silvestres 相似文献
796.
This study presents an integrated framework for the analysis of options of agricultural development and natural resource management at the ecosystem level. Pujiang County in Zhejiang Province, China, is used as a case-study area. The IMGLP model is applied to maximize regional agricultural economic surplus and labor market conditions in Pujiang. The consequences of four poverty reduction strategies (intensification of production, diversification toward livestock production, land expansion, and exit from agriculture) are determined for a set of regional poverty and biodiversity indicators. Diversification seems to be the most promising poverty reduction strategy, but requires an efficient use of animal manure in cropping systems to avoid environmental problems. Improved nutrient management in cropping systems is effective in reducing the regional nitrogen surplus, but less effective in increasing per capita income. The exit strategy is beneficial for reducing poverty and achieving biodiversity, but may have important social consequences that are not addressed in this study. Further reduction of rural poverty is hampered by labor constraints during the harvesting period for high-value crops such as vegetables and fruits. These constraints can be overcome by intensive research and development in the field of agricultural mechanization. 相似文献
797.
Abstract: We developed a method with which to analyze a specie's response to chronic anthropogenic disturbance (CAD). We regressed density of individuals on the intensity of 3 disturbance agents (human activities, raising livestock, and land degradation) along CAD gradients to determine how much CAD is experienced by a species; whether species are ruderal (achieving maximum densities in disturbed sites); whether density declines as a result of CAD; which disturbance agents are responsible for this reduction; and the number of populations that decline as a result of CAD. We tested the method on 9 threatened Mammillaria species (Cactaceae). Seven species were ruderal. In 4 species, actual disturbance surpassed the CAD intensity in which plants achieved their maximum densities; thus, the density of those 4 species appeared to be declining. For 7 species, some populations were threatened by human activities or livestock, whereas others were favored by them. Land degradation negatively affected all species. Our results allowed us to distinguish 4 groups of species that had similar responses and thus may require different forms of management. Our method provided an estimation of the growth rate (λ) of the studied populations that was significantly correlated with λs obtained from demographic studies. The size structures of populations were consistent with the predictions of the analysis, which suggests our results are consistent and reliable. Disturbance–response analysis provides a basis for management in heavily populated areas, where conservation must be achieved along with development activities that cause CAD. The method provides readily interpretable information, which facilitates participative decision making; the data are rapidly generated, which makes it appropriate when results are required promptly or for assessment of large numbers of species; and it provides a comprehensive perception of how threatened species behave in the real world. 相似文献
798.
公共场所人群聚集的风险影响因素众多,其随机性和不确定性强,对风险进行定量比较困难.在前人研究的基础上,对事故进行分类,并根据事故发生概率和与其相应的概率分布,通过数学推导和参数补偿,提出了个人风险定量计算模型.最后以公共场所的部分事故统计资料为参考数据,阐述了该模型的使用方法和步骤,同时指出使用该模型过程中应该注意的问题.结果表明,该模型具有一定的合理性和准确性,对公共场所人群聚集安全具有一定的指导意义.根据模型的计算结果,建议一般公共场所个人风险的推荐值为4.50×10-7. 相似文献
799.
上海市中心城区公园绿地对居住区的社会服务功能定量分析 总被引:1,自引:0,他引:1
城市公园绿地的社会服务功能是城市绿地系统生态服务功能的重要组成;评价其社会服务功能需同时考虑服务的公平性和有效性。为科学合理的定量分析城市公园绿地的部分社会服务功能,建立了一套评价体系,包括公园绿地服务范围覆盖率、公园绿地服务重叠度和单位面积公园绿地服务人口数等3项指标。以上海市中心城区为例,介绍了3项指标的定义;基于地理信息系统平台实现了计算流程,并对上海市中心城区主要公园绿地对于居住区的社会服务功能进行了定量分析。研究表明:2009年上海市中心城区的主要公园绿地对于居住区的服务范围覆盖率已超过80%,服务重叠度平均值为221,单位面积公园绿地服务人口数的平均值为117人/m2。3项指标可为城市公园绿地的社会服务功能分析提供有效的定量研究手段 相似文献
800.