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排序方式: 共有109条查询结果,搜索用时 250 毫秒
81.
"生态保护红线、环境质量底线、自然资源利用上线和环境准入负面清单"(简称"三线一单")是一项重大环境管理制度创新,目前国家已经发布相关编制技术指南(试行),并在长江经济带12省市全面启动编制工作,其中划定大气环境质量底线是"三线一单"的核心内容之一。本文结合生态环境部"三线一单"试点城市编制实践,从大气环境质量底线内涵与框架、技术方法、管控措施设计等方面,提出大气环境质量底线体系与划分技术方法,以期为进一步规范"三线一单"编制技术奠定基础。  相似文献   
82.
单级序批式生物膜反应器(SBBR)多途径生物脱氮研究   总被引:2,自引:0,他引:2  
徐峥勇  杨朝晖  曾光明  王荣娟  肖勇  许朕 《环境科学》2007,28(10):2326-2331
利用传统微生物分析技术与PCR、变性梯度凝胶电泳(DGGE)等分子生物学技术相结合的方法,对单级SBBR反应器中的主要生物脱氮途径进行分析.结果表明,亚硝化-厌氧氨氧化-反硝化途径是主要的脱氮途径,通过该途径去除的NH+4-N占总去除量的65%以上;另外2条途径则分别是亚硝化-反硝化途径以及全程硝化-反硝化途径.所有途径都采取同步和分步2种方式完成,同步方式以曝气阶段的氮素亏损形式予以表现.分步方式则依靠各种脱氮微生物在曝气阶段和厌氧阶段不同的活性程度完成,亚硝酸细菌是曝气阶段的主要活性菌种,完成NH+4-N向NO-2-N的转化,而厌氧氨氧化细菌和反硝化细菌则在厌氧阶段成为优势菌种,完成完整的生物脱氮过程.  相似文献   
83.
There is large usage of polybrominated diphenyl ethers (PBDEs) especially for decabromodiphenyl ether (BDE-209, Deca-BDE) in controlling the risks of fire. The toxicological effects of PBDEs are worth being concerned about. Female SD rats were daily gavaged with BDE-209 ether at the dose of 100 mg/kg for 20 days. Histological observation was performed for the screening of the target organs for BDE-209 exposure. The distribution and metabolism of PBDEs in the exposed main organs were evidenced by HRGC-HRMS. Alterations of the endogenous metabolite concentrations in urine were investigated using metabonomic approaches based on IH NMR spectrum. Histopathological changes including serious edema in kidney, hepatocellular spotty necrosis and perivasculitis in liver indicated that BDE-209 caused potential influences on endogenous metabolism in the exposed liver and the kidney. BDE-209 was found to be highly accumulated in lipid, ovary, kidney and liver after 20 days' exposure. Occurrence of other lower brominated PBDEs in the rats demonstrated that reductive debromination process happened in vivo. Hydroxylated and methoxylated-BDEs, as metabolism products, were also detected in the rat tissues. A total of 12 different endogenous metabolites showed obvious alterations in urine from the exposed rats, indicating the disturbance of the corresponding internal biochemical processes induced by BDE-209 exposure. These findings in vivo suggested the potential health risk might be of concern due to the toxicological effects of BDE-209 as a ubiquitous compound in the environment.  相似文献   
84.
Studies show a direct relationship between occurrence of asthma and increases of particulate matter in the air. Private transportation is found to be a significant contributor to this problem. The objective of this article is to explore this link between air pollution, asthma and vehicular dependency in order to provide recommendations for health and transport policy. This article focuses on the survey of literature on the relationship between vehicular air pollution and asthma; combining it with the literature on vehicular dependency or ‘car culture’ in the global context and in The Netherlands. This article exposes the imbalance of power between patient groups and polluting industries, and the government failure to protect the weaker party can be explained by corporate pressures. It will be argued that since air pollution is tied to the corporate support for the car industry and vested interests in promoting a ‘car culture’, strategic policy that claims to be concerned with public health should explicitly link the present pattern of mobility to public health. This article concludes with a recommendation for raising environmental health awareness by explicitly linking vehicular dependency to respiratory health through a combination of holistic and citizenship education.  相似文献   
85.
我国西北地区退耕地植被恢复基本途径与模式探讨   总被引:4,自引:0,他引:4  
本文在试验研究,实地考察的基础上,基于中国西部退奈还林还草工程的实背景,现状及研究基础,通过对国外相关实中践进行分析,提出了西北地区退耕地植被恢复的思路和“以封山育林为主,辅之以人工措施”的基本建设,并提出了不同景观立地条件下的56种植被恢复模式。  相似文献   
86.
Satisfaction of communities living close to forests with forest management authorities is essential for ensuring continued support for conservation efforts. However, more often than not, community satisfaction is not systematically elicited, analyzed, and incorporated in conservation decisions. This study attempts to elicit levels of community satisfaction with three management approaches of Kakamega forest in Kenya and analyze factors influencing them. Three distinct management approaches are applied by three different authorities: an incentive-based approach of the Forest Department (FD), a protectionist approach of the Kenya Wildlife Service (KWS), and a quasi-private incentive-based approach of Quakers Church Mission (QCM). Data was obtained from a random sample of about 360 households living within a 10-km radius around the forest margin. The protectionist approach was ranked highest overall for its performance in forest management. Results indicate that households are influenced by different factors in their ranking of management approaches. Educated households and those located far from market centers are likely to be dissatisfied with all the three management approaches. The location of the households from the forest margin influences negatively the satisfaction with the protectionist approach, whereas land size, a proxy for durable assets, has a similar effect on the private incentive based approach of the QCM. In conclusion, this article indicates a number of policy implications that can enable the different authorities and their management approaches to gain approval of the local communities.  相似文献   
87.
Anti‐desertification planning in Iran operates at the national level through the Five Year Development Plans, the National Plan to Combat Desertification — a long‐running scheme for which the Forest, Rangeland and Watershed Management Organisation (FRWO) is responsible — and the recently developed National Action Programme to Combat Desertification (the NAP). The Iranian NAP was formulated following the country's ratification of the United Nations Convention to Combat Desertification and drew heavily on the experience, expertise and collaboration of personnel in FRWO. Development and implementation of the NAP has had major policy impacts in Iran in the two main areas of generating cross‐sectoral cooperation between government instruments at the national planning level and by community participation in local projects to combat desertification. Documenting the evolution of cross‐sectoral and participatory approaches to desertification in Iran shows that the NAP provided impetus towards a transformation of previous procedures, a policy impact that is continuing to generate change.  相似文献   
88.
适应气候变化的分析框架及政策涵义   总被引:1,自引:0,他引:1  
适应气候变化与发展议题密切相关,这也使得适应成为一个过于宽泛的命题,影响了对适应内涵的理解。首先,本文基于国内外对适应问题的探讨,提出了适应气候变化的基本分析框架,即基于不同发展阶段的适应需求,区分增量型适应和发展型适应,并通过工程性适应、技术性适应和制度性适应三种适应手段增强适应能力。增量型适应是指在系统现有基础上考虑新增风险所需的增量投入,这种适应所针对的是发展需求基本得到满足,仅仅需要应对新增的气候风险所需的适应活动;发展型适应是指由于发展水平滞后,使得系统应对常规风险的能力和投入不足,需要协同考虑发展需求及新增的气候风险。其次,分析了适应的四个基本步骤,即:①评估气候风险及脆弱性;②甄别各种可能的适应对策;③选择可行的适应措施;④推荐"成功"的适应行动。还介绍了相应的社会经济分析方法,如脆弱性评估、社会经济影响评估、适应的成本效益分析等。最后,基于中国适应气候变化的基本需求及优先领域,提出了相应的政策建议,如开发农业适应技术、加强流域综合治理、开展健康风险监测、实施灾害保险计划等。  相似文献   
89.
水体沉积物重金属生物有效性及评价方法   总被引:1,自引:0,他引:1  
在研究以重金属为主要污染物的水体中,通常把沉积物视为探索环境重金属污染的工具。由于沉积物中重金属化学行为和生态效应的复杂性,对沉积物中重金属生物有效性的研究是当前学术界的热点研究课题。本文就沉积物中重金属的生物有效性及沉积物质量评价方法作了简要评述。包括沉积物对水生生物的作用机理,孔隙水重金属浓度的估算,沉积物质量评价方法,沉积物质量基准。  相似文献   
90.
Traditional high resolution mass spectrometry (HRMS) analysis for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) can be time consuming and expensive. Consequently, alternative methods are of great interest to regulatory agencies and others characterizing contaminated sites. One factor that hinders acceptance of alternative methods is a lack of performance information that assesses the alternative method's impacts on analytical results. The U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation Monitoring and Measurement Technologies Program (EPA SITE MMT) encourages the development and implementation of innovative and alternative monitoring methods by providing performance information on site characterization technologies. This paper presents a comparison of the results obtained from laboratory-based alternative approaches for screening sediment and soil samples for dioxin toxicity equivalents (TEQ(D/F)) to results obtained using traditional HRMS. The laboratory-based approaches included modifying the traditional HRMS analysis to make it more cost-effective (alternate 1613B), analyzing extracts that had been prepared for HRMS using low resolution mass spectrometry, and determining total organic carbon (TOC) content as an indicator of PCDD/F content. These comparisons demonstrated that TEQ(D/F) values generated using toxicity equivalency factors proposed by the World Health Organization in 1998 applied to alternate 1613B and LRMS analyses have a strong linear correlation to the TEQ(D/F) values derived in the same fashion from traditional HRMS analysis. These results would have placed >90% of the samples within the same concentration intervals using ranges of <0.05, 0.05-0.50, 0.50-5, and >5ng TEQ/g. Natural log transformed data for TOC had significantly weaker correlation to TEQ(D/F), indicating that TOC is not a reliable indicator of TEQ(D/F) concentrations.  相似文献   
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