石羊河流域的生态环境问题、引发原因与治理对策

石羊河是甘肃省三大内陆河之一,在河西乃至全省经济社会发展中起着十分重要的作用.目前该流域出现森林面积减少,雪线上升,水土流失加重,地下水位下降,水体污染,水质恶化,荒漠化蔓延等一系列生态环境问题,已经严重影响和制约到流域及其周边地区的经济建设和社会安定团结.为实现流域生态大系统及其子系统稳定、健康、持续发展,应坚持"南保水源,中建绿洲,北治风沙"的基本原则.对流域大系统,要切实加强流域水资源统一管理,完善政策体系,加强环境保护的执法、宣传,提高流域民众的生态意识,加强生态建设工程的科技支撑.对流域南部祁连山区,要加强林区管理,理顺体制,加强山区植被保护和建设,提高水源涵养能力,减少水土流失,合理调整水库,减少汛期蓄水.对中部绿洲,要发展二三产业,加快小城镇建设,调整农业产业结构,加强农田防护林体系建设,加大节水力度,实施外流域调水工程.对北部荒漠区,要恢复、重建退化固沙植被,退耕还草还荒,严禁新的土地开垦,适度发展沙产业.     

Comparing urban solid waste recycling from the viewpoint of urban metabolism based on physical input-output model: A case of Suzhou in China

Investigating impacts of urban solid waste recycling on urban metabolism contributes to sustainable urban solid waste management and urban sustainability. Using a physical input-output model and scenario analysis, urban metabolism of Suzhou in 2015 is predicted and impacts of four categories of solid waste recycling on urban metabolism are illustrated: scrap tire recycling, food waste recycling, fly ash recycling and sludge recycling. Sludge recycling has positive effects on reducing all material flows. Thus, sludge recycling for biogas is regarded as an accepted method. Moreover, technical levels of scrap tire recycling and food waste recycling should be improved to produce positive effects on reducing more material flows. Fly ash recycling for cement production has negative effects on reducing all material flows except solid wastes. Thus, other fly ash utilization methods should be exploited. In addition, the utilization and treatment of secondary wastes from food waste recycling and sludge recycling should be concerned.     

WATER QUALITY IN MOUNTAIN RECREATIONAL AREAS1

ABSTRACT: Several seasons of water quality study in the eastern Sierra Nevada have provided much useful information. One study element focused in detail on a representative drainage: Bishop Creek, from sampled locations at 12,800 feet to the Owens River at 4,000 feet. Sub-studies ranged from geohydrology, through chemical and bacterial quality, to benthic ecology. A coordinated study also was made of spatial patterns of use. A second element focused on non-point source monitoring the length of the Inyo National Forest. From physical, chemical, and bacterial standpoints, water quality is generally very good. Strains of pathogenic bacteria have been confirmed, and substantial further work to establish the importance of their presence is needed. Recreational use survey results have been analyzed to produce a methodology permitting management of the resource as needed. In addition, basic policy recommendations to easily minimize risk have been developed.     

Development of Macroinvertebrate-Based Index for Bioassessment of Idaho Rivers

Theoretical constructs, such as the river continuum concept, predict that the composition of benthic fauna in rivers will be different from that of headwater streams. There exists a need to modify, for use on larger rivers, the bioassessment techniques commonly used on small streams. Using aquatic macroinvertebrates and the “reference condition” approach, we developed and tested a multimetric index for use on the rivers of Idaho. Reference sites were selected to represent the best current conditions (i.e., least impacted) among Idaho rivers. The index performed well in distinguishing reference sites from sites displaying some form of anthropogenic impairment. Individual metrics used in the index included: number of EPT taxa, total number of taxa, percent dominant taxon, percent Elmidae, and percent predators. The index we developed for Idaho rivers was essentially a modification of a framework designed for small streams, suggesting that techniques, including data analysis, currently used for streams can be adapted for use on larger rivers. Adapting these methods for use in rivers is primarily a matter of (1) selecting metrics relevant to the rivers of interest; (2) expanding the field sampling to encompass the greater habitat area and, potentially, heterogeneity of rivers; and (3) selecting an appropriate form of data analysis. The approach we describe here should be applicable to geographic regions other than Idaho.     

Reflections in a Stock Pond: Are Anthropogenically Derived Freshwater Ecosystems Natural, Artificial, or Something Else?

“A skyscraper is as natural as a bird’s nest” –Alan Watts For millennia, people have altered freshwater ecosystems directly through water development and indirectly by global change and surrounding land-use activities. In these altered ecosystems, human impacts can be subtle and are sometimes overlooked by the people who manage them. This article provides two case studies near Boulder, Colorado that demonstrate how perceptions regarding these ecosystems affect their management. These examples are typical of lakes and streams along the Front Range of Colorado that are simultaneously natural and social in origin. Although natural, many of the region’s freshwater ecosystems are affected by ongoing ecologic, hydrologic, chemical, and geomorphic modifications produced by human activity. People and nature are both active participants in the production of these freshwater ecosystems. The concept of “hybridity,” borrowed from geographers and social scientists, is useful for describing landscapes of natural and social origin. Hybrid freshwater ecosystems are features of the humanized landscape and are derived from deliberate cultural activities, nonhuman physical and biological processes, and incidental anthropogenic disturbance. Our perceptions of “natural” freshwater ecosystems and what definitions we use to describe them influences our view of hybrid systems and, in turn, affects management decisions regarding them. This work stresses the importance of understanding the underlying societal forces and cultural values responsible for the creation of hybrid freshwater ecosystems as a central step in their conservation and management.     

Integrating industrial ecology principles into a set of environmental sustainability indicators for technology assessment

This paper focuses on the environmental component of sustainability of technology, taking into account the role of industrial ecology. Assessment of environmental sustainability of technology traditionally focuses on immediate impact of technology on the environment through quantifying resource extraction and generated emissions. However, technology does not only exchange materials with the environment but also with the industrial society as a whole, the so-called industrial metabolism. A higher compatibility of a specific technology with the industrial system, as studied in industrial ecology, can result in lower resource extraction and reduced waste emission, indirectly contributing to a better environmental sustainability.Starting from the considerations above and based on the second law of thermodynamics, the paper presents a set of five environmental sustainability indicators for the assessment of products and production pathways, integrating industrial ecology principles. The indicators, all scaled between 0 and 1, take into account: (1) renewability of resources; (2) toxicity of emissions; (3) input of used materials; (4) recoverability of products at the end of their use; (5) process efficiency.The applicability of the elaborated set of indicators is illustrated for different production pathways of alcohols (petrochemical and oleochemical based), polyethylene end-of-life options and electricity production from non-renewable (natural gas and fossil oil) and renewable resources (hydropower, photovoltaic conversion of solar irradiation).     

"生态优先"原则指导下的南沙湿地资源开发利用与保护

南沙由于其优越的地理位置和丰富的资源,对于广州的发展有着重要的战略作用.南沙开发规划提出了＂生态优先＂的原则,以实现经济与生态保护的双赢.在介绍了生态优先原则内涵的基础上,提出生态优先的实现要依据生态调查结果,评价生态价值并进行生态规划.以此为思路,对南沙湿地资源开发利用生态优先的实现进行了探讨,认为可以通过绝对生态优先与相对生态优先两个角度来实现,根据不同的优先程度提出建立保护区、提高科技与管理水平、适度开发利用等.     

ABATEMENT OF GROUND WATER PHOSPHATE IN GIANT CANE AND FOREST RIPARIAN BUFFERS1

ABSTRACT: Forest and grass riparian buffers have been shown to be effective best management practices for controlling nonpoint source pollution. However, little research has been conducted on giant cane [Arundinaria gigantea (Walt. Muhl.)], a formerly common bamboo species, native to the lower midwestern and southeastern United States, and its ability to reduce nutrient loads to streams. From May 2002 through May 2003, orthophosphate or dissolved reactive phosphate (DRP) concentrations in ground water were measured at successive distances from the field edge through 12 m of riparian buffers of both giant cane and mixed hardwood forest along three streams draining agricultural land in the Cache River watershed in southern Illinois. Giant cane and mixed hardwood forest did not differ in their DRP sequestration abilities. Ground water DRP concentrations were significantly reduced (14 percent) in the first 1.5 m of the buffers, and there was an overall 28 percent reduction in DRP concentration by 12 m from the field edge. The relatively low DRP reductions compared to other studies could be attributed to high DRP input levels, narrow (12 m) buffer lengths, and/or mature (28 to 48 year old) riparian vegetation.     

长江三峡库区连阴雨的气候特征分析

本文利用长江三峡库区34个气象站1961～2001年的逐日降水资料,分析了库区连阴雨发生频次、持续时间的时空分布特征.结果表明,近40多年来,长江三峡库区年及秋季降水日数以及春、秋季降水量都存在减少趋势.降水量和降水日数的变化会导致连阴雨天气特征发生一定改变.统计表明,近40多年来,库区平均年连阴雨频次有微弱的减少趋势,主要发生在库区西部和南部地区,这种减少趋势主要是由于秋季连阴雨的减少造成的.按照连阴雨影响范围和严重程度的年型划分的统计结果也表明,库区秋季连阴雨在近40多年来有明显的减弱,1960年代至1970年代中期是三峡库区秋季连阴雨的多发季节,秋雨影响范围广、程度重,1970年代后期以来,特别是1990年代后期,秋季连阴雨影响程度明显减弱.     

我国气象灾害的分类与防灾减灾对策

本文根据气象灾害特征、致灾因子和天气现象类型,将我国的气象灾害划分为7大类20种.为了适应科学防灾减灾和社会、经济快速发展的需求,必须加快大气监测、信息加工和气象灾害预警能力为主要内容的气象现代化建设;加强气象灾害的机理研究;制定科学防灾减灾对策.