生物炭的土壤环境效应及其机制研究

近年来,随着土壤污染的逐渐加重以及食品安全问题的频出,生物炭作为重要的土壤改良剂以及对污染土壤修复表现出的巨大潜力引起人们的广泛关注.本文首先对国内外生物炭的土壤环境效应方面的研究以及成果进行分析总结.生物炭具有疏松多孔的性质以及巨大的表面积和阳离子交换量(CEC),可以改善土壤理化性质,能强烈吸附土壤中的污染物,降低其生物有效性和迁移转化能力;生物炭的碱性对于改良酸性土壤降低土壤中污染物的生物毒性具有很大的潜力;生物炭还可以为微生物提供生长繁殖的场所,有利于微生物对污染物的降解,但同时又可以保护被吸附的有机物免受微生物的降解,对不同的微生物影响不同;生物炭可以对蚯蚓等土壤动物的生存产生影响.在此基础上,依据生物炭的基本理化性质,对其土壤环境效应机制进行了分析.最后,从当前工作中存在的不足对今后的研究重点和方向进行了展望.     

Oxidative stress in the freshwater cyprinid crucian carp (Carassius carassius L.) upon chronic exposure to endosulfan

Oxidative stress and antioxidant responses of crucian carp, upon chronic exposure to endosulfan, were evaluated in vivo. The lethal concentration (LC_50–96?h) was 70 μg L^?1; on its basis, the fish were exposed to endosulfan at 20, 35, and 50 μg L^?1 and autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28, and 35. Lipid peroxidation was induced in a concentration-dependent manner, being highest at 50 μg L^?1 (3/4 LC_{50–96 h}, sub-lethal concentration-I, SL-I) on day 4 (720% versus control), followed in its extent (490%) at 30 μg L^?1 (1/2 LC_{50–96 h}, sub-lethal concentration-II, SL-II) on day 7 and lowest (260%) at 10 μg L^?1 (1/4 LC_{50–96 h}, sub-lethal concentration-III, SL-III) on day 14. Glutathione showed a concentration- and time-dependent elevation in the initial phase, with highest level on day 4 (180%) at SL-I, but showed significant reduction in all test concentrations from day 21 of post-exposure. Superoxide dismutase was decreased significantly throughout the study, with highest reduction (63%) on day 4 at SL-I; catalase increased in all test concentrations up to day 14 but showed a significant decrease from the day 28 of post-exposure. The potential role of these parameters as indicators of pesticide pollution in aquatic systems is discussed.     

Pesticide in the Mississippi River floodplain and its possible linkage to colon cancer risk in the US

Result of this study shows that elevated colorectal cancer risk in Mississippi River floodplain of the United States is likely linked to historically high pesticide application. Mississippi River basin produces about 80% of major US crops and has about two-thirds of US pesticides used for agriculture. Historically, heavy pesticide application and agricultural irrigation were reported to result in high pesticide residues in surface water, fish and wells of Mississippi embayment. Risk ratio of colorectal cancer incidence in 86 counties of Mississippi River floodplain was about 29% higher than that of other counties in the 48 contiguous states. Risk ratio of colon cancer mortality in 63 counties of Mississippi embayment was 33% higher than that of other counties in the 48 states between 1999 and 2016. Risk ratios of colorectal cancer incidence and colon cancer mortality in Mississippi River floodplain are higher after smoking and diabetes factors were filtered off. Previous studies have linked exposure to pesticide with type-II diabetes and the latter was linked to increasing colon cancer risk by about 27%. Result here suggests that pesticide may be an independent risk factor directly associated with elevated colon cancer risk in Mississippi River floodplain.     

Environmental and energy-related challenges to sustainable tourism in the United States and China

This article examines the relationship between tourism, energy, and environment. This article approaches tourism as a complex adaptive system composed of consumers, transportation providers, travel intermediaries, and destinations composed of multiple tourism-related companies and other stakeholder groups. Environmental and energy-related challenges of components to the system are examined as well as various units – the system as a whole, enterprises and individuals – within the system. A total of 92 peer-reviewed articles were studied that address ‘energy’ and ‘tourism’ published between 1974 and 2011. Also addressed are the impacts of social and cultural differences between the United States and China concerning responses to environmental and energy-related challenges. This article concludes with recommendations for addressing the challenges associated with such challenges, including building system capacity, technology development and adoption, support of individual behavior change, increasing understanding of the trade-offs and interactions within the system, and adoption of multidisciplinary approaches to these challenges within the tourism system.     

Principal sustainability components: empirical analysis of synergies between the three pillars of sustainability

Starting from the concept of three fundamental sustainability dimensions (environmental, social, and economic), this study investigated professional contributions to sustainability by means of principal component analysis (PCA). Graduates from the Environmental Sciences program (N?=?542) at ETH Zurich described their best professional contributions to sustainable development. Next, they evaluated whether their best practice example contributed to achieving any of the five environmental, social, and economic objectives of the Swiss national sustainability strategy. These judgments served as the basis for a PCA aiming to identify principal sustainability components (PSCs) covering typical synergies between sustainability objectives within and transcending the three fundamental dimensions. Three PSCs capturing important synergies were identified. PSC 1 Product and Process Development reflects how ecological innovation and modernization can generate social and economic benefits and at the same time facilitate the reduction in use of as well as the responsible use of natural resources. PSC 2 Education and Social Economics reflects how educational activities and sociocultural sustainability initiatives can simultaneously promote income and employment, social and human capital, and free personal development. PSC 3 Protection of Nature and Humans covers the synergetic benefits which protection of natural spaces and biodiversity and the reduction of environmental risks have for the protection of health and safety of the population. The study also revealed that integration of environmental, social, and economic aspects is often connected to conflicts between these dimensions. However, contributions which consider the economic situation of future generations or enhance social and human capital achieved considerable integration but showed no inclination toward such conflicts.     

水稻基因类型与生长环境对精米中砷积累的影响

砷(As)是动植物非必需的有毒类金属。水稻是对As有较强吸收和富集能力的大宗粮食作物,大米的食用是我国及东南亚地区人体暴露As的最主要途径,严重威胁人体健康。水稻籽粒中As的积累与水稻的基因型及众多环境因子密切相关,而且表现出复杂的交互作用。在浙江省选择了不同土壤砷背景值的5块水稻田,同时在嘉兴市农科院布置了人工添加As的盆栽实验,比较了20个水稻品种在这6个实验点的精米中As含量。结果表明,水稻基因型与环境及其相互作用对水稻籽粒中As的积累均有极显著影响,并且筛选得到了5个精米中As含量较低的基因型:秀水128、秀水09、秀水134、甬粳16和Y-05-8。     

Databanks of data sources for environmental chemicals

There exist a vast variety of data sources, either manual sources or computerized databases in the field of environmental chemicals. To facilitate the access and to retrieve the information wanted efficiently, we built up two “databanks of data sources”, one called “Databank of Manual Sources (DMAS)” and the other named “Databank of Databases (DADB)”. The set‐up of these databanks is explained and the load status statistics are shown. DMAS has 164 and DADB 106 hits.     

A critique of ethical and social issues of genetically modified crops

SUMMARY

The ethical and social issues of genetically modified crops as reported by the Nuffield Bioethics Committee are summarised. A critique of their findings is presented. It is argued that the apparent benefits are outweighed by the ecological, social and economic costs, and that the yields of some genetically modified crops are poorer when compared to conventional species. Furthermore, the current regulations are far too lax for consumer protection. There is an urgent need for a critical and disinterested review of the scientific basis of the research.     

Higher education in urban environmental management: a new programme at the Asian Institute of Technology,Bangkok

Environmental management and planning is now considered as a new field of professional expertise. There are even professional associations for interested professionals. To date, urban environmental management has been regarded as a subdiscipline of environmental management, but since the Rio Conference in 1992, with the new focus of urban management on environmental problems, it can itself be considered as a professional field. This paper traces the emergence of the field and tries to identify the new skills required for it. The question of formal training, in higher education, for a new type of professional is raised and discussed. It refers at length to an initiative taken by the Asian Institute of Technology (Bangkok) to propose and offer a new graduate programme in this discipline, and draws on the author's experience of an Asian workshop (Bangkok, May 1993) aimed at defining the need for such a new profession in Asia.