Eco-environmental changes and causative analysis in the source regions of the Yangtze and Yellow Rivers, China

In the most recent four decades the eco-environment in the source regions of the Yangtze and Yellow Rivers has been continuously getting worse, this is mainly manifested in the serious vegetation degradation, rapidly developing desertification, lake shrinkage and salinization, wetland degradation and biodiversity reduction. This paper attempts to give a quantitative analysis to such eco-environmental changes and explore their causes. The main factors responsible for such changes are climate change and the alterations of glacial snow accumulation and the freeze-thaw processes of the frozen soil, as well as overgrazing and rodent damage. The eco-environmental changes in the source regions not only influence the social-economic development of these regions but also have affected, or are affecting, the whole river basins' social-economic development.     

Assessing Major Ecosystem Types and the Challenge of Sustainability in Turkey

In recent years, Turkey has experienced rapid economic and population growth coupled with both an equally rapid increase in energy consumption and a vast disparity in welfare between socioeconomic groups and regions. In turn, these pressures have accelerated the destruction of productive, assimilative, and regenerative capacities of the ecosystems, which are essential for the well-being of the people and the economy. This paper describes the structure and function of major ecosystem types in Turkey and discusses the underlying causes of environmental degradation in the framework of economy, energy, environment, and ethics. From a national perspective, this paper suggests three sustainability-based policies necessary for Turkey's long-term interests that balance economic, environmental, and energy goals: (1) decoupling economic growth from energy consumption growth through the development of energy-efficient and renewable energy technologies; (2) linking economic efficiency and distributive justice of wealth and power through distributive and participatory public policies; and (3) integrating the economic and ecological systems through the internalization of externalities and ecosystem rehabilitation.     

湖泊沉积物中硫的地球化学循环机制研究

湖泊沉积物中的硫是控制氧化还原体系的重要元素之一。湖泊硫酸盐还原作用主要发生在沉积物表层几厘米范围内,界面硫酸盐还原具有双重环境效应。硫酸盐还原主要形成黄铁矿和有机硫,黄铁矿的生成要受到沉积物中硫酸盐、有机质以及铁氧化物活性的控制。单硫化物不稳定,并且会影响沉积物中重金属的迁移。     

CHANNEL INSTABILITY IN THE LOESS AREA OF THE MIDWESTERN UNITED STATES1

ABSTRACT: The bess area of the midwestern United States contains thousands of miles of unstable stream channels that are undergoing system‐wide channel‐adjustment processes as a result of (1) modifications to drainage basins dating back to the turn of the 20th century, including land clearing and poor soil‐conservation practices, which caused the filling of stream channels, and consequently (2) direct, human modifications to stream channels such as dredging and straightening to improve drainage conditions and reduce the frequency of out‐of‐bank flows. Today, many of these channels are still highly unstable and threaten bridges, other structures, and land adjacent to the channels. The most severe, widespread instabilities are in western Iowa where a thick cap of bess and the lack of sand‐and gravel‐sized bed sediments in many channels hinders downstream aggradation, bed‐level recovery and the consequent reduction of bank heights, and renewed bank stability. In contrast, streams draining west‐central Illinois, east‐central Iowa, and other areas, where the bess cap is relatively thin and there are ample supplies of sand‐and gravel‐sized material, are closer to recovery. Throughout the region, however, channel widening by mass‐wasting processes is the dominant adjustment process.     

Consequences of Pollution and Degradation of Nigerian Aquatic Environment on Fisheries Resources

Throughout the world, human use of water, and bad planning have led to drier and polluted rivers, lakes, and groundwater resources with dramatic effects on the natural ecosystems. Nigeria's vast freshwater resources are among those most affected by environmental stress imposed by human population growth, urbanization, and industrialization. Disposal and management of wastes in Nigeria present serious environmental problems. The usual methods of waste disposal in the country are: land filling, dumpsites, land spreads, water disposal, and incineration. Each of these methods has serious environmental implications because of their potential to pollute and contaminate underground and surface water bodies in the country. Major cities in Nigeria face serious water pollution crises, in which lack of environmental control of water-dependent activities (including domestic, agricultural, and industrial) play an important part. Fish and marine resources in the country face total collapse or extinction, due to over-fishing and destruction of marine life and natural habitats by pollution of water bodies. Unregulated and excessive use of pesticides for fishing and the deliberate disposal and dumping of toxic and hazardous wastes into water bodies are significant causes of massive fish kills and loss of aquatic life and habitats in the country. The protection of water quality and aquatic ecosystem as a vulnerable resource, essential to sustain life, development and environment is of utmost importance to prevent further pollution and degradation of Nigeria's freshwater resources. Integrating operational measures for safeguarding adequate levels of protection of endemic habitats remains a major challenge. There is therefore a need to examine in tandem the entire range of uses to which freshwater is put, and to design services which neither squander precious resources nor fail to respect other, competing and complementary water needs.This paper attempts to provide an overview of the Nigerian freshwater resources, to assess the pollution status of inland waters, identify the sources of pollution, and infer the consequent effect on fisheries resource. Recommendations were proffered on the strategies to employ to ensure that Nigerian fishery resources are adequately managed in order to address the issue of food security.     

处理生物难降解物质的有效方式--共代谢

介绍了共代谢的类型、特点和影响因素。共代谢过程针对各种生物难降解物质需选择各自合适的一级基质，而且一级基质与难降解物质需保持合适的浓度比；共代谢过程中微生物不仅需要足够的C、N、P等营养元素，而且微量营养元素的加入也是必须的。考虑各方面因素并有效地控制才能使难降解物质达到较高的共代谢率。     

微生物降解炼油厂含酚废水的实验研究

采用燕化集团公司炼油事业部污水厂的活性污泥为菌源 ,好氧条件下通过分离、驯化筛选出三种高效降酚微生物。并在实验室模拟三相生物流化床分别对人工含酚废水和燕山石化炼油厂含酚废水进行降解实验 ,结果显示 ,在三相生物流化床中使用微生物包埋法制作的海藻酸钙载体处理含酚废水 ,3小时段内降酚显著 ,t -testP <0 0 1,处理效果良好 ,并以海藻酸钠为主要原料制作载体可以极大降低处理成本     

Removal of Cinnamic Acid Derivatives from Aqueous Effluents by Fenton and Fenton-like Processes as an Alternative to Direct Biological Treatment

The removal of various phenolic acids (p-coumaric, caffeic and ferulic acids), typically found in wastewaters of agricultural origin, from model effluents by chemical and biological means has been investigated. Chemical oxidation processes comprising hydrogen peroxide and a homogeneous or heterogeneous copper or iron catalyst were employed over a wide range of experimental conditions. Chemical oxidation is capable of removing most of the total organic carbon initially present in the effluent at relatively mild treatment conditions (i.e. reaction times up to 120 min and temperatures up to 80°C), while removal rates generally increase with increasing temperature, H₂O₂ and catalyst concentrations. The anaerobic degradability and toxicity of p-coumaric acid has been assessed using the biochemical methane potential and anaerobic toxicity assay respectively. p-Coumaric acid, at concentrations below about 1 g/L, is not toxic against methanogens and slowly degrades over a period of about 35 days at 35°C. In light of this, chemical oxidation may provide a promising alternative to direct biological treatment for either the partial or complete removal of phenolic acids at reasonable treatment times; the implications for wastewater treatment are discussed.     

Solid phase microextraction (SPME) as an effective means to isolate degradation products in polymers

A new sample preparation technique, solid phase microextraction (SPME), was compared with direct headspace-GC-MS with respect to the type and amount of identified compounds. Three types of LDPE films containing photosensitising additives according to the Scott-Gilead patents and pure LDPE were used as model substances. The polyethylene films were thermally aged at 80‡C after the induction period was surpassed by subjecting the materials to 100 h of UV radiation. The new SPME method was developed using nonpolar poly(dimethylsiloxane) and polar carbowax fibers to extract the low molecular weight products formed in the polyethylene films during aging. Many more products were identified after SPME followed by GC-MS than after direct headspace-GC-MS of the samples. The SPME method allowed the identification of homologous series of carboxylic acids, ketones, and furanones, while direct headspace-GC-MS identified only a few carboxylic acids (C1-C6) and small amounts of some ketones and furanones. In general, SPME was more effective in extracting less volatile products, and in particular, the polar carbowax fiber identified also C7-C12 carboxylic acids and 4-oxopentanoic acid. By SEC and FTIR we confirmed that the number and amount of former degradation products correlated well with the decrease in molecular weights and the amount of formed carbonyl compounds.     

Land resources potential and sustainable land management: an overview

Land degradation continues to be a major threat to local and national food security. With limited potential to develop new land, any increase in agricultural production must be sought largely through the better use of land already under cultivation. Concerns for the global environment associated with agriculture worldwide have also increased in recent years and require more coordinated efforts at global and national levels with decentralisation of activities at the local level.
This article presents an overview of land resources potential for food production, the processes and extent of land degradation and its economic and environmental costs and impacts, and highlights some macro-economic policies and institutional measures for the prevention of land degradation and rehabilitation of degraded lands. A people-centred programme is presented as a basis for decentralising activities for sustainable land use and land management. Finally, the need for better coordinated efforts of concerned UN, multinational agencies and NGOs for the implementation of Agenda 21 and related conventions is stressed.