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991.
稻壳基活性炭的制备及其对亚甲基蓝吸附的研究 总被引:8,自引:3,他引:5
以稻壳为原料,采用K2CO3活化法和H3P04活化法制备了比表面积为1312m^2/g和682m^2/g的活性炭,通过扫描电子显微镜(SEM)、X-射线衍射仪(XRD)对样品进行了表征,并将孔隙发达的活性炭样品用于对亚甲基蓝的吸附,结果表明,K2CO3活化法制备的活性炭样品具有更多的微孔结构;随着亚甲基蓝溶液初始浓度的增加、活性炭吸附时间的延长,亚甲基蓝的去除率呈现逐渐降低和逐渐增大的变化规律,当pH值为6时,活性炭对亚甲基蓝的吸附效果最佳;稻壳基活性炭对亚甲基蓝的吸附等温线符合Langmuir模型,Qm最高可达476.2mg/g;热力学参数△G^0△H^0和△S^0均为负值,表明稻壳基活性炭对亚甲基蓝的吸附是一个自发的放热反应。 相似文献
992.
Despite the popularity of marine protected areas (MPAs) as a management tool, increasing evidence shows that many fail to
achieve conservation objectives. Although several MPAs exist in Sri Lanka, most are not managed, and resource extraction and
habitat degradation continue unabated. At present, the declaration and management of MPAs is carried out without adequate
consideration of the ecology, socioeconomic realities, or long-term management sustainability. Managers have focused more
toward the creation of new legislation and protected areas rather than ensuring the implementation of existing regulations
and management of existing protected areas. Poor coordination and a lack of serious political will have also hindered successful
resource management. As in other developing countries, MPA managers have to contend with coastal communities that are directly
dependant on marine resources for their subsistence. This often makes it unfeasible to exclude resource users, and MPAs have
failed to attract necessary government support because many politicians are partial toward the immediate needs of local communities
for both economic and political reasons. A more integrated approach, and decisions based on the analysis of all relevant criteria
combined with a concerted and genuine effort toward implementing strategies and achieving predetermined targets, is needed
for effective management of MPAs and the sustainable use of marine resources in Sri Lanka. 相似文献
993.
Defining Indicators and Standards for Tourism Impacts in Protected Areas: Cape Range National Park,Australia 总被引:2,自引:0,他引:2
Visitors’ perceptions of impacts and acceptable standards for environmental conditions can provide essential information for
the sustainable management of tourist destinations, especially protected areas. To this end, visitor surveys were administered
during the peak visitor season in Cape Range National Park, on the northwest coast of Western Australia and adjacent to the
iconic Ningaloo Reef. The central focus was visitors’ perceptions regarding environmental conditions and standards for potential
indicators. Conditions considered of greatest importance in determining visitors’ quality of experience included litter, inadequate
disposal of human waste, presence of wildlife, levels of noise, and access to beach and ocean. Standards were determined,
based on visitors’ perceptions, for a range of site-specific and non-site-specific indicators, with standards for facilities
(e.g., acceptable number of parking bays, signs) and for negative environmental impacts (e.g., levels of littering, erosion)
sought. The proposed standards varied significantly between sites for the facilities indicators; however, there was no significant
difference between sites for environmental impacts. For the facilities, the standards proposed by visitors were closely related
to the existing situation, suggesting that they were satisfied with the status quo. These results are considered in the context
of current research interest in the efficacy of visitor-derived standards as a basis for protected area management. 相似文献
994.
Applying Gap Analysis and a Comparison Index to Evaluate Protected Areas in Thailand 总被引:1,自引:0,他引:1
Trisurat Y 《Environmental management》2007,39(2):235-245
Protected areas in Thailand were first established 40 years ago. The total area of existing protected areas covers 18.2% of
the country’s land area and the Class 1 Watershed, another form of protection, encompasses 18.1%. The government of Thailand
intends to increase protected area systems to 25% of the country in 2006 and 30% in 2016. There are always questions arising
about how much is enough protected areas to effectively protect biodiversity. The objective of this article is to assess the
representation of ecosystems in the protected area network. This article also recommends which underrepresented ecosystems
should be added to fill the gaps in representativeness. The research applies a gap analysis and a comparison index to assess
the representation of ecosystems within the protected area network. The spatial analyses were applied to measure three aspects
of representativeness, namely forest type, altitude, and natural land system. The analyses indicate that the existing protected
area system covers 24.4% of the country’s land area, nearly meeting the 25% target proposed by the National Forest Policy;
and 83.8% of these areas are under forest cover. Most protected areas are situated in high altitudes, where biological diversity
is less than in lowlands. Mangrove forest and riparian floodplain are extremely underrepresented in the existing system. Peat
swamp forest, dry dipterocarp forest, and beach forest are relatively well represented. In addition, these five ecosystems
are threatened by human pressures and natural disasters; therefore, they should be targeted as high priorities for the selection
of new reserves. Future research should incorporate aquatic and marine ecosystems, as well as animal distributions, which
were not included in this research due to data unavailabilities. 相似文献
995.
通过梳理国内外海陆统筹实践进程和政策演变,界定海陆统筹的基本概念与内涵,在国土空间规划背景下,探讨海陆统筹的关键问题和挑战,并进一步提出海陆统筹的优化路径。研究表明:(1)海陆统筹是一种“流”空间理论思维下面向全域全要素的开发保护战略,通过统一筹划海陆两大系统的资源要素配置、产业联动、生境共治、空间互联和制度互嵌,促进沿海地区协同高效发展,提升生产、生活和生态空间品质。(2)国土空间规划视角下海陆统筹面临的主要问题与挑战包括:海陆空间边界不明晰、海陆经济系统不协调、海陆资源开发与生境保护不统一和海陆空间规划体系不兼容。(3)针对现状问题与挑战,基于空间、经济、生态和管治四个维度,构建全域全要素、分级、分功能的统筹优化路径,以期为沿海地区的海陆协调发展提供借鉴。 相似文献
996.
Shuidi He Minjuan Huang Lianming Zheng Ming Chang Weihua Chen Qianqian Xie Xuemei Wang 《环境科学学报(英文版)》2022,34(4):444-453
This study attempts to identify the dominant transport pathways, potential source areas, and their seasonal variation at sites with high inorganic nitrogen (IN) wet deposition flux in southern China. This is a long-term study (2010–2017) based on continuous deposition measurements at the Guangzhou urban site (GZ) and the Dinghushan Natural Reserve site (DHS) located in the Pearl River Delta (PRD) region. A dataset on monthly IN concentration in precipitation and wet deposition flux were provided. The average annual fluxes measured at both sites (GZ: 33.04±9.52, DHS: 20.52±10.22 kg N/(ha∙year)) were higher, while the ratios of reduced to oxidized N (GZ: 1.19±0.77, DHS: 1.25±0.84) were lower compared with the national mean level and the previous reported level throughout the PRD region. The dominant pathways were not always consistent with the highest proportional trajectory clusters. The transport pathways contributing most of deposition were identified in the north and north-northeast in the dry season and in the east-southeast, east, and south-southwest in the wet season. A weighted potential source contribution function (WPSCF) value >0.3 was determined reasonably to define the potential source area. Emission within the PRD region contributed the majority (≥95% at both sites) of the IN deposition in the wet season, while the contribution outside the region increased significantly in the dry season (GZ: 27.86%, DHS: 95.26%). Our results could help create more effective policy to control precursor emissions for IN fluxes, enabling reduction of the ecological risks due to excessive nitrogen. 相似文献
997.
行蓄洪区可持续发展战略探讨 总被引:8,自引:0,他引:8
人水共处是我国行蓄洪区无可回避的现实,实现行蓄洪区可持续发展是关系到防洪安全建设和区内人民生活和经济发展的重要课题。本文在分析我国行蓄洪区现状及所问题的基础上,提出了行蓄洪区可持续发展的基本模式,进一步从实施洪水保险,鼓励移民、产业结构高速等方面搪塞了保障行蓄洪区可持续发展的政策。 相似文献
998.
我国灾害地貌及其防治研究中的几个问题 总被引:4,自引:1,他引:4
本文通过对我国灾害地貌及其防治研究工作的初步分析,提出了我国目前灾害地貌及其防治研究中存在的诸如灾害地貌系统、灾害地貌防治工作的规范化、灾害地貌防治系统的优化、灾害地貌防治效益的评估以及灾害地貌预测预报和危险区划研究等方面的理论与实践问题,指出了在灾害地貌及其防治研究中应引起重视的若干方面。 相似文献
999.
Morville S Scheyer A Mirabel P Millet M 《Environmental science and pollution research international》2006,13(2):83-89
Goal, Scope and Background Atmospheric sampling (gas and particles) of 5 phenols (phenol, m-cresol, p-cresol, o-cresol, pentachlorophenol) and 15 nitrophenols
(3-methyl-2-nitrophenol, 3-nitrophenol, 4-methyl-2-nitrophenol, 5-methyl-2-nitrophenol, 2-methyl-3nitrophenol, 3-methyl-4-nitrophenol,
2,6-dinitrophenol, bromoxynil, 2,5-dinitrophenol, 2,6-dinitro-p-cresol, 2,4-dinitrophenol, ioxynil, DNOC, 3,4-dinitrophenol,
dinoseb) on XAD-2 resin (20 gr) and glass fibre filters, respectively, were performed in 2002 by using 'Digitel DA80' high
volume samplers. These measurements were undertaken in order to show spatial and geographical variations of concentrations
and the role of traffic in the emissions of these compounds to the atmosphere.
Methods Sampling were performed in Strasbourg (eastern France), in its vicinity (Schiltigheim) and in Erstein. Sites were chosen
to be representative of urban (Strasbourg), suburban (Schiltigheim) and rural (Erstein) conditions. Field campaigns were undertaken
simultaneously in urban and suburban sites during all the seasons during 4 hours at a flow rate of 60 m3.h-1, which gives
a total of 240 m3 of air per sample. Period of sampling varied between 06h00 to 10h00, 11h00 to 15h00 and 18h00 to 22h00 in
order to evaluate a variation of concentration during automobile traffic between urban, suburban and rural areas. Gas and
particle samples were separately Soxhlet extracted for 12 h with a mixture of CH2Cl2 / n-hexane (50:50 v/v), concentrated
to about 1 mL with a rotary evaporated and finally dried under nitrogen. Dry extracts were dissolved in 1 mL of CH3CN. Before
analysis, extracts were sylilated by using MTBSTFA. Analysis was performed by GC/MSD in the SIM mode.
Results and Discussion Partitioning of phenolic compounds between gas and particle phases seems to be mainly correlated with vapour pressure. Among
phenolic compounds analysed, phenol, p-cresol, pentachlorophenol and 2.4-dinitrophenol were detected in all samples and emissions
from traffic seems to be the major source for the presence of these compounds to the atmosphere. No increase of concentrations
in autumn tend to confirm this hypothesis since, with the use of domestic heating in colder months, increases of PAHs concentrations
were observed and these compounds are known to be emitted by all combustion processes.
Pentachlorophenol is a special case since this molecule is only used as wood preservative. Its presence in all atmospheric
samples, whatever the locations and the period of time is the consequence of its persistence.
Conclusions and Perspectives These measurements demonstrate that phenols and nitrophenols are emitted to the atmosphere and further measurements, in order
to confirm their sources, their behaviour and their potential impact to the air quality and to human health should be undertaken
especially since the literature collected is relatively old. Concentrations of pentachlorophenol measured are very low and,
due to its toxicity, further investigations should be undertaken.
- * The basis of this peer-reviewed paper is a presentation at the 9th FECS Conference on 'Chemistry and Environment', 29 August
to 1 September 2004, Bordeaux, France. 相似文献
1000.
JULIA OHL-SCHACHERER‡ GLENN H. SHEPARD Jr . HILLARD KAPLAN† CARLOS A. PERES TAAL LEVI DOUGLAS W. YU 《Conservation biology》2007,21(5):1174-1185
Abstract: The presence of indigenous people in tropical parks has fueled a debate over whether people in parks are conservation allies or direct threats to biodiversity. A well-known example is the Matsigenka (or Machiguenga) population residing in Manu National Park in Peruvian Amazonia. Because the exploitation of wild meat (or bushmeat), especially large vertebrates, represents the most significant internal threat to biodiversity in Manu, we analyzed 1 year of participatory monitoring of game offtake in two Matsigenka native communities within Manu Park (102,397 consumer days and 2,089 prey items). We used the Robinson and Redford (1991) index to identify five prey species hunted at or above maximum sustainable yield within the ∼150-km2 core hunting zones of the two communities: woolly monkey (Lagothrix lagotricha), spider monkey (Ateles chamek), white-lipped peccary (Tayassu pecari), Razor-billed Currasow (Mitu tuberosa), and Spix's Guan (Penelope jacquacu). There was little or no evidence that any of these five species has become depleted, other than locally, despite a near doubling of the human population since 1988. Hunter–prey profiles have not changed since 1988, and there has been little change in per capita consumption rates or mean prey weights. The current offtake by the Matsigenka appears to be sustainable, apparently due to source–sink dynamics. Source–sink dynamics imply that even with continued human population growth within a settlement, offtake for each hunted species will eventually reach an asymptote. Thus, stabilizing the Matsigenka population around existing settlements should be a primary policy goal for Manu Park. 相似文献