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881.
华东森林及高山背景区域SO2、NOx、CO本底特征   总被引:2,自引:0,他引:2  
国家大气背景监测福建武夷山站是中国华东区域背景站点之一,可代表华东森林及高山区域背景状况。为了解该区域的大气背景状况,评估区域污染现状以及污染物输送在区域污染中的作用,选取福建武夷山背景站2011年3月至2012年2月主要气体污染物(SO2、NOx、CO)为期1年的监测数据,研究各污染物在不同时间尺度的浓度变化特征和相关关系,以及与气象因子的相关关系,并利用后向轨迹模式探讨区域输送对华东森林及高山背景区域各气体污染物质量浓度的影响。结果表明,武夷山背景点监测期间SO2、NOx、CO的平均质量浓度分别为3.9、5.1、409.8 μg/m3,且具有明显的季节变化特征,春、冬季明显高于夏、秋季;三者日变化幅度均很小,呈现出单谷型分布型态,说明武夷山背景点受人为活动的影响很小,主要受气象条件影响;相关性分析结果显示,SO2与NOx浓度相关性较好,与湿度有较好的负相关,与风速在冬季具有一定的正相关,NOx与CO浓度在秋季和冬季的相关性较好,且二者与温度的负相关性较好。后向轨迹分析结果表明,SO2全年最大浓度峰值主要来自北方采暖季燃煤排放的远距离输送影响,NOx、CO全年最大值则源于生物质燃烧的远距离输送影响。  相似文献   
882.
张杨  杨洋  江平  邓红蒂  祁帆  李强  常献伟  程鹏 《自然资源学报》2022,37(11):3005-3018
山水林田湖草生命共同体是对人与自然和谐统一关系的新认知,是生态文明理论的重要组成部分。以建立一个山水林田湖草生命共同体的研究范式为目的,系统剖析了山水林田湖草生命共同体理论与应用在基础探索、快速发展和多元繁荣三个阶段的研究重点与特征;再次审视了山水林田湖草生命共同体的内涵、阐明了概念新认知、基本特征、人与生命共同体关系;最后提出面向山水林田湖草生命共同体的“问题—目标—时空策略—目的”的实施路径,及构建以自然资源监测监管体系、自然资源资产产权体系、国土空间规划体系、国土空间用途管制体系、国土空间生态修复体系、法律法规体系等为主的制度体系,进而提升其科学性和实用性,为构建国土空间治理体系及治理能力现代化提供决策支撑。  相似文献   
883.
Municipal Solid Waste Management (MSWM) is considered to be one of the most serious environmental issues in the Philippines. The annual waste generation was estimated at 10.6 million tonnes in 2012 and this is expected to double in 2025. The Republic Act (RA) No. 9003, widely known as the Ecological Solid Waste Management Act of 2000, provides the required policy framework, institutional mechanisms and mandate to the Local Government Units (LGUs) to achieve 25% waste reduction target through establishing an integrated solid waste management plan based on the 3Rs (reduce, reuse and recycling). Although the initial impact of the LGUs is still very limited in implementing the national mandate, this article highlights the successful experiences of Cebu, the second largest city in the Philippines, in reducing its MSW generation by more than 30% in the past three years. This study also explores the implementation process, innovative actions taken by the Cebu City Government in implementing the national mandate at local level and identifies the factors that influence the policy implementation. The findings suggest that the impacts of the national mandate can be achieved if the LGUs have the high degree of political commitment, planning and development of effective local strategies in a collaborative manner to meet with local conditions, partnership building with other stakeholders, capacity development, adequate financing and incentives, and in the close monitoring and evaluation of performance.  相似文献   
884.
Levels of lead, zinc, cadmium, copper and nickel were determined in roadside moss samples within towns in the northern and south-eastern regions of Nigeria. Average lead level in the south-east (59 ppm) was higher than the average for the northern region (44 ppm). Average levels of zinc, cadmium, copper and nickel did not differ significantly between the two regions, with overall averages for the entire study area being 50.9, 1.2, 11.3 and 5.6 ppm for these metals. Lead levels were poorly correlated with those of the other metals, indicating that automobile emissions may not be the main source for these metals in the moss. In comparison with a previous study of the south-west region, the results indicate a generally slightly higher level of metal pollution in the south-west region than in both the northern and south-eastern regions.  相似文献   
885.
886.
Wang, Jinxia, Jikun Huang, Lijuan Zhang, Qiuqiong Huang, and Scott Rozelle, 2010. Water Governance and Water Use Efficiency: The Five Principles of WUA Management and Performance in China. Journal of the American Water Resources Association (JAWRA) 46(4): 665-685. DOI: 10.1111/j.1752-1688.2010.00439.x Abstract: In recent years China has attempted to reform water management by decentralizing water management responsibilities. The overall goal of our paper is to better understand the emergence of water user associations (WUAs) in China and assess if they are adhering to the practices spelled out by the Five Principles, a set of recommended practices that are supposed to lead to successful WUA operation. Using four sets of different types of villages to examine implementation and performance, we find that World Bank-supported WUA villages (“Bank villages”) can be thought of as operating mostly according to the Five Principles. For example, the Bank villages were endowed with a more reliable water supply; were set up and were operating with a relatively high degree of farmer participation; and leaders were more consultative and the process more formal. When WUAs are run according to the Five Principals, we show that WUAs increase water use efficiency. The study also provides evidence that there is a perception in the Bank villages that water management is improving in general and that there is less conflict both within the village and among villages. Perhaps more importantly, we find that the Bank’s effort to promote WUAs extended beyond their own project villages. The openness, consultative nature, and transparency found in the Bank WUAs are also found (albeit at a somewhat lower level) in the non-Bank WUA villages.  相似文献   
887.
The pesticide usages are controlled by comparing residue concentrations in treated commodities to legally permitted maximum levels (MRLs) determined based on supervised trials designed to reflect likely maximum residues occurring in practice following authorised use. The number of trials available may significantly affect the accuracy of estimated maximum residues. We conducted a study with synthetic lognormal distributions with mean of 1 and standard deviations of 0.8 and 1.0, which reflect the residue distributions observed in practice. The likely residues in samples were modelled by drawing random samples of size 3, 5, 10 and 25 from the synthetic populations. The results indicate that the estimations of highest residues (HR), used for calculation of short-term intake, and the MRLs, serving as legal limits, are very uncertain based on 3–5 trials indicated by the calculated HR0.975/HR0.025 and MRL0.975/MRL0.025 ratios of 12 and 9, and 13 and 10, respectively, which question the suitability of such trials for the intended purpose. As the 95% range of HR and MRL rapidly decreases with number of trials, ideally ≥15 but minimum 6–8 trials should be used for estimation of HR and MRL according to the current typical practice of Codex Alimentarius.  相似文献   
888.
The photochemical fate of seven sulfonamides was investigated in matrices representative of natural water bodies under various light sources. Fundamental photolysis parameters such as molar absorption coefficient, quantum yield (QY) and first-order rate constants were determined. The photolysis decay rate was dependent on the protonation state of the molecule, pH of the water sample and dissolved organic matter. Natural organic matter was the most significant factor in the indirect photolysis of sulfonamides. Half-lives were in the range of minutes at 254 nm to days under natural sunlight. Under natural sunlight, all sulfonamides showed higher removal rates in natural waters implying that indirect photolysis is the predominant mechanism.  相似文献   
889.
China's circular economy is still at the initial stage, whose development has many difficulties and problems requir- ing immediate resolution theoretically and practically. Due to the differences of re...  相似文献   
890.
Abstract: The intensely regulated Murray‐Darling Basin in southeastern Australia is the nation's most extensive and economically important river system, and it contains fragmented populations of numerous fish species. Among these is the Murray hardyhead (Craterocephalus fluviatilis), a species listed as endangered (International Union for Conservation of Nature Red List) in the mid‐1990s prior to its acute decline with the progression of a severe drought that began in 1997. We compared the genetic structure of Murray hardyhead with 4 congeneric species (Darling hardyhead[C. amniculus], Finke hardyhead[C. centralis], Lake Eyre hardyhead[C. eyresii], and unspecked hardyhead[C. stercusmuscarum]), selected on the basis of their taxonomic or biological similarity to Murray hardyhead, in order to affirm species boundaries and test for instances of introgressive hybridization, which may influence species ecology and conservation prospects. We used allozyme (52 loci) and mtDNA markers (1999 bp of ATPase and cytochrome b) to provide a comparative genetic assessment of 139 Murray hardyhead, which represented all extant and some recently extirpated populations, and 71 congeneric specimens from 12 populations. We confirmed that Murray hardyhead and Darling hardyhead are taxonomically distinct and identified a number of potential conservation units, defined with genetic criteria, in both species. We also found allozyme and mtDNA evidence of historic genetic exchange between these 2 allopatric species, apparently involving one population of each species at the geographic edge of the species’ ranges, not in the most proximate populations sampled. Our results provide information on species boundaries and offer insight into the likely causes of high genetic diversity in certain populations, results which are already being used to guide national recovery planning and local action. Given the prevalence of incorrect taxonomies and introgression in many organismal groups, we believe these data point to the need to commence genetic investigations of any threatened species from an initially broad taxonomic focus.  相似文献   
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