An ecological approach to environmental impact assessment

Carbon cycling analysis is presented as a means for assessing anthropogenic perturbations in an ecosystem. Data from oligotrophic, eutrophic, and dystrophic (bog) lakes are used to show general trends in the lacustrine carbon cycle. The oligotrophic lake is an unstressed system and the eutrophic lake is under nutrient enrichment with high algal standing crops and productivity. The bog lake is a pH-stressed environment that is primarily a grazing ecosystem. It is hoped that a more effective environmental impact assessment will result from the use of carbon cycling as a unifying concept in ecosystem analysis.     

EFFECT OF WOODY DEBRIS ENTRAPMENT ON FLOW RESISTANCE1

ABSTRACT: Recent environmental concerns in floodplain management have stimulated research of the effect vegetation and debris have on flow conveyance, and their function in a productive riparian ecosystem. Although the effect of stable, in-channel woody debris formations on flow resistance has been noted by several authors, studies concerning entrapment of detrital debris in vegetation are lacking. Logs, limbs, branches, leaves and other debris transported during flooding often become lodged against bridges, hydraulic structures, trees and vegetation, and other obstacles, particularly in and near the overbank areas. Hydraulic measurements obtained in a channel prior to and following the removal of woody debris indicated that the average Manning's n value was 39 percent greater when woody debris was present. An examination of the drag-velocity relation for vegetation indicated that an increase in the frontal area of debris and/or vegetation results in a nearly proportional increase in Manning's n. The influence of debris on flow resistance decreased as flow depth increased.     

Emerging trends in mining industry partnerships

The article analyzes mining company partnerships in terms of four main counterparts, namely: the sovereign, owners and financial backers, the workforce, and local communities. The main characteristics of mining partnerships under the four aspects are discussed. Taxation and financial aspects are also considered. Case studies from the British coal industry and examples from Latin America are part of the article. Downsizing and labour relations are also discussed, as well as indigenous peoples' issues. The article concludes that, successful minerals companies in the future will be those that work with communities, applying the highest standards of social responsibility. This includes safety, environmental management and good business ethics.     

Life-cycle assessment of 11 kV electrical overhead lines and underground cables

The life-cycle impacts of five different 11 kV electrical power cables (three overhead lines and two underground cables) were analysed. These were compared by their embodied impacts in production and total lifetime operational impacts. The life-cycle results revealed there to be three key issues, the impacts of climate change, fossil fuel depletion, and particulate matter formation (PMF). The former two were of particular significance. The embodied impacts, which are those associated with the materials, were generally determined to be insignificant. The exception was for underground cables at low operating loads. Under these conditions PMF was more significant as a result of the high embodied impacts of the cables. Further analysis revealed that these impacts could be mitigated with an end of life material recovery program. At present the underground cables are not recovered, but if they were the recycling benefits would give rise to a notable improvement in PMF. For the other impact categories operational conductor losses were the dominant cause of impacts. In summary it was concluded that to minimise the life-cycle impacts of 11 kV cables the system with the lowest conductor resistance should be selected.     

Assessment of two thermally treated drill mud wastes for landfill containment applications.

Offshore oil and gas drilling operations generate significant amounts of drill mud waste, some of which is transported onshore for subsequent thermal treatment (i.e. via thermal remediation). This treatment process results in a mineral waste by-product (referred to as thermally treated drill mud waste; TTDMW). Bentonites are originally present in many of the drill mud products and it is hypothesized that TTDMW can be utilized in landfill containment applications (i.e. cover or base liner). The objective of this paper is to examine the feasibility of this application by performing various physical and chemical tests on two TTDMW samples. It is shown that the two TTDMW samples contained relatively small amounts of clay-sized minerals although hydraulic conductivity values are found to be less than 10(-8) m/s. Organic carbon contents of the samples were approximately 2%. Mineralogy characterization of the samples confirmed varying amounts of smectite, however, peak friction angles for a TTDMW sample was greater than 36 degrees. Chemical characterization of the TTDMW samples show potential leaching of barium and small amounts of other heavy metals. Discussion is provided in the paper on suggestions to assist in overcoming regulatory issues associated with utilization of TTDMW in landfill containment applications.     

Environmental and Strategic Uncertainty in Common Property Management: The Case of Scottish Red Deer

The range of red deer populations in the Scottish Highlands can cover several different landholdings (estates), many of which derive their income primarily from the private hunting (stalking) of stags. The deer belong to nobody and their seasonal movement does not respect the boundaries of individual estates, but a 'rule of capture' does apply as, once shot, the deer become the property of the estate owner. This paper argues that deer populations would best be managed as a common property resource. Indeed, for this reason, the Deer Commission for Scotland has encouraged owners to form Deer Management Groups. These groups are now able to utilize a computer program that models the relationship between grazing quality and population dynamics. However, drawing upon examples from the Western Highlands, the paper finds that common property management must overcome incentives to behave strategically that arise from the characteristics of flow and storage of the resource. The problem is aggravated by the degradation of the habitat that has occurred over centuries. This often means that the resource is below its optimum in terms of stag numbers and quality. Scientific models are an important contribution, but only reduce the environmental uncertainty. Their full potential can only be realized if all landowners are obliged to actively engage in common property management.     

The Use of Hydrogen Release Compound for the Accelerated Bioremediation of Anaerobically Degradable Contaminants: The Advent of Time-Release Electron Donors

Hydrogen Release Compound (HRC®) is a simple, passive, low-cost, and long-term option for the anaerobic bioremediation of chlorinated hydrocarbons (CHs) via reductive dehalogenation. Applications to the remediation of other compounds, such as MTBE and perchlorate, that are anaerobically degradable by other reductive mechanisms, are in progress. HRC should be viewed as a tool for the acceleration of natural attenuation at sites that would otherwise require high levels of capital investment and operating expense. HRC is a proprietary, food-quality, polylactate ester that, upon being deposited into the subsurface, slowly degrades to lactic acid. Lactic acid is then metabolized to hydrogen, which in turn drives the reductive dechlorination of CHs. This has been demonstrated effectively in the laboratory and in the field. HRC can be manufactured as a moderately flowable, injectable material, or as a thicker, implantable hard gel, to facilitate localized treatment and passive barrier designs. HRC is best utilized for the remediation of dissolved phase plumes and the associated hydrophobically sorbed contaminant. The use of HRC is not appropriate for use on free-phase DNAPL unless the total mass to be remediated is within the scope of economic feasibility in comparison to alternative treatments. Evidence suggests there is competition between reductive dehalogenators and methanogens in which the methanogens compete for the use of hydrogen in the conversion of carbon dioxide to methane. Some researchers believe that a low concentration of hydrogen favors the reductive dehalogenators and starves out the methanogens. The objective, therefore, is to keep hydrogen concentrations low. The time-release feature of HRC, which is based on the hydrolysis rate of lactic acid from the ester and the subsequent lag time to hydrogen conversion, facilitates this objective. HRC, therefore, becomes a passive form of accelerated natural attenuation, in contrast to the more capital-and management-intensive alternatives now available. Laboratory and field results are presented, the latter expanding on the first uses of HRC by various members of the engineering and consulting firm community. © 1999 John Wiley & Sons, Inc.     

旅游业焦点常设栏目,报道可持续旅游领域的发展,和联合国环境规划署旅游计划的活动威尔士农村旅游业:一个范例计划

最近制订的威尔士西南半岛上的"Landsker Borderlands"(意为风景如画的边塞)农村旅游业计划兼备了历史的、文化的和娱乐的吸引力.这个南彭布鲁克什尔农村社区行动伙伴关系(SPARC)的综合项目是一个更广泛举措的一个组成部分,旨在改善当地人民的经济生活与社会生活,和增强环境.在描述了制订一项计划所涉及的过程以及该旅游产品本身之后,确认了SPARC思路中对长期成功和可持续性至关重要的显著特色.这些特色包括:鼓励所有发展阶段的最大限度社区参与;利用专家"伙伴"向农村社区提供所需要的技术资源与财务资源;针对旅游业、农业和环境的互补战略;和一个明确的战略性规划与实施框架.一个成功项目的这些要素可以加以适配和应用于各种各样地点.     

Toward understanding the human dimensions of the rapidly changing arctic system: insights and approaches from five HARC projects

Human dimensions research focuses on the interrelationships between humans and the environment. To date, human dimensions research in arctic regions has concentrated primarily on local events and contexts. As such, it complements analysis elsewhere of adaptation and sustainable development within broad institutional, social, and environmental contexts. This paper reviews five projects from the Human Dimensions of the Arctic System (HARC) initiative, established by the US National Science Foundation in 1997. Common themes and findings are highlighted: climatic variations or change affect societies through interactions with human activities; population dynamics provide key quantitative indicators of social impacts and well being; and specific impacts and responses are the result of complex, context-sensitive interactions. Congruent approaches to the challenges of interdisciplinary research are also identified: multivariate time plots aid the integration of data, retrospective and prospective studies are part of a continuum and reinforce one another, comparative studies are essential for understanding general principles of human dimensions, and arctic residents can play a vital role in research and action.