中国工业系统各行业综合污染度评价方法与实例

中国的环境问题很大程度上与高强度和低效益的工业经济活动有关.降低工业系统污染程度无疑对我国建设资源节约型和环境友好型社会具有重要意义.对工韭系统各行业污染度进行定量化的综合评价,得到单一化的污染度指数,可方便不同行业间清洁水平的比较,可为各地区工业布局和工业结构的调整提供理论依据.本文初步建立了中国工业系统污染度综合评价的方法,并对栽"十五"期间(2001-2005)我国重点调查的41个工业行业的综合污染度进行了评价,得到了各行业的综合污染度评价指数、排名及其变化情况.结果表明,"十五"期间,我国工业系统污染度总体上有较大幅度的降低,各行业污染度差别较大,有的行业污染度有大幅下降,有的行业还有所增加.本文的研究成果可为建设资源节约型和环境友好型社会提供重要理论支持.     

Rangeland dynamics in southern Ethiopia: (1) botanical composition of grasses and soil characteristics in relation to land-use and distance from water in semi-arid Borana rangelands

The distribution and compositional pattern of the grass layer, as well as soil quality of southern Ethiopian semi-arid rangelands were examined under three land-use systems (communal land, government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. In total, 49 grass species were identified, 65% of which were perennials. Of the most commonly distributed highly desirable species, Chrysopogon aucheri showed the greatest frequency under the traditional grazing reserve (27.6%), and the lowest in the communal land (14.0%). The frequency of Cenchrus ciliaris was similar in all the study sites. The proportion of Lepthotrium senegalensis was low under the land-use systems (3.9%) and increased away from water sources (2.3%). Of the less desirable species, Sporobulus nervosus was extremely more abundant (<0.05) in the communal land (13.3%) than the traditional grazing reserve (3.3%) and the government ranch (1.9%). Sporobolus pyramidalis was dominant in the study sites, with similar (P>0.05) frequency percentages under the land-use systems and along the distance gradients from water. Basal cover was low and similar on all the study sites (3.3%). Concerning the soil texture, sand (71.1%) constituted the largest proportion, followed by silt (21.3%) and lastly, clay (7.7%). With regard to soil exchangeable cations, organic C and total nitrogen were generally low and did not show marked variation in all the study sites. The study showed significant differences for most of the vegetation variables between the communal land and the other land-uses. This suggested that grazing intensity was higher in the communal land and moderate in the government ranch and in the traditional grazing reserves (kallos). The lack of significant differences in most of the studied (vegetation) variables along the distance gradient from water could be ascribed to the fact that grazing disturbance has already exceeded a certain threshold of degradation. Under the present low states of soil nutrients and rainfall, cultivation is neither sustainable nor environmentally friendly and this will lead to further degradation of the soil in these marginal lands.     

Deteriorated watersheds can be restored: A case study

A project in west-central Colorado demonstrated that a watershed dissected by a dense gully network can be stabilized and rehabilitated. Check dam systems, aided by improved vegetative cover through reduced cattle grazing and plantings, stabilized not only the structurally treated gullies, but also gullies within the network that were not structurally treated. Comparison with untreated gullies located outside of the project area, showed that the outside gullies widened three times as much as the structurally untreated inside gullies. Statistical analysis indicated that precipitation was normal during the treatment and evaluation period.Check dams decreased gully depth by accumulating sediment deposits. In turn, gully bank stabilization was hastened and alluvial aquifer volumes increased. This increase, plus higher infiltration rates as a result of denser vegetation, led to renewed perennial streamflow after 7 treatment years.Within 11 years after treatment, check dam systems and improved vegetation reduced sediment loads in the flows by more than 90 percent, providing a substantial benefit to farmlands and ponds downstream.From this work we are able to conclude that only part of a gully network requires structural treatment. The mainstem gully, and those tributaries controlling the local base levels of others, are the critical segments that should be structurally treated.     

Local recycling of plant nutrients from small-scale wastewater systems to farmland—A Swedish scenario study

Reducing the negative impact from on-site systems and promoting recycling are important tasks for municipal authorities, especially as regards phosphorus. The objective of this scenario study was to compare energy turnover in a life cycle perspective, recycling potential and expected reduction of nitrogen and phosphorus emissions for three upgraded small-scale wastewater systems based on local recycling of plant nutrients. The systems studied were urine separation, blackwater separation and chemical precipitation in the septic tank. The urine was sanitised through storage, the blackwater through liquid composting and the precipitated sludge through chemical treatment with urea before reuse in agriculture. The system boundaries included the operational phase as well as investment in capital goods required for upgrading the existing on-site systems.The urine separation system used least energy. The potential recycling and reduction of phosphorus was lower than for the other two systems, while that of nitrogen was higher than for the chemical precipitation system but lower than for the blackwater separation system. The blackwater separation system reduced both nitrogen and phosphorus to a high extent and also enabled a large proportion of both nitrogen and phosphorus to be recycled to arable land. However, a major drawback with this system was its significantly higher use of electricity, related to the aeration and stirring required when sanitising the blackwater by liquid composting. When urea treatment replaced liquid composting, the use of electricity decreased substantially in the blackwater separation system. The chemical precipitation system was efficient in reducing and recycling phosphorus, while inefficient for nitrogen. The use of fossil fuels was significantly higher than for the other two systems, primarily due to the production of the precipitation chemical.     

人为失误与应激

探讨了人机系统中人为失误与不同应激的相关性.按照模糊集理论,根据成员功能结构,提出了定义正常应激范围的方法以及过高过低应激导致的事故等不良后果.     

论我国"三同时"制度立法缺陷

本文着重对"三同时"制度的立法进行研究,通过对有关法律条文的比较,揭示出"三同时"制度立法所存在的各种问题,并提出相应的对策,以使我国"三同时"制度立法更加完善.     

MANAGING THE COLORADO RIVER IN A SEVERE SUSTAINED DROUGHT AN EVALUATION OF INSTITUTIONAL OPTIONS1

ABSTRACT: This paper presents a summary of the findings and recommendations of the studies of severe, sustained drought reported in this special issue. The management facilities and institutions were found to be effective in protecting consumptive water users against drought, but much less effective in protecting nonconsumptive uses. Changes in intrastate water management were found to be effective in reducing the monetary value of damages, through reallocating shortages to low-valued uses, while only water banking and water marketing, among the possible interstate rule changes, were similarly effective. Players representing the basin states and the federal government in three gaming experiments were unable to agree upon and effect major changes in operating rules. The conclusions are (1) that nonconsumptive water uses are highly vulnerable to drought, (2) that consumptive uses are well-protected, (3) that drought risk is greatest in the Upper Basin, (4) that the Lower Basin suffers from chronic water shortage but bears little drought risk, (5) that opportunities exist for win-win rule changes, (6) that such rule changes are extremely difficult to make, and (7) that intrastate drought management is very effective ^m in reducing potential damages.     

我国城市可持续发展对智能运输系统管理规划的需求分析

本文在分析我国城市可持续发展对智能运输系统管理规划的需求的基础上，指出了我国城市交通存在的问题，并根据我国城市的特点，提出了制定城市智能运输系统管理规划的原则和注意事项，并对城市智能运输系统管理规划的总体结构和总体配置，以及实施步骤提出了设想。     

南方红壤丘陵区的农业景观特征与农业布局

分析了南方红壤丘陵区农业景观特征,提出该区重点治理的生态脆弱带为低丘岗地,认为该地带的人为干扰和自然作用不相协调是本区农业景观的不良演替的原因。初步探讨了通过农业合理布局,促进该区景观恢复的途径。指出作物布局和土壤耕作对低丘岗地保护、开发及景观恢复等方面的意义。     

Land use Systems and Erosion in the Uplands of the Central Coast, Vietnam

Soil erosion is a significant problem in the uplands of the Central Coast, Vietnam. It affects the livelihood of farmers and could hinder the long-term economic development efforts in the uplands. Yet, trapped in poverty, upland farmers, especially the ethnic minority, are still mining the soil using erosive land use systems to meet their urgent needs. This study demonstrates that the level of soil erosion varies across the typical land use systems. The fruit tree-based agroforestry (AF) system is least erosive and most financially profitable. The choice of land use system is influenced by farmers' attributes, land plot characteristics, and policy-related variables. The set of policy variables is important in explaining land use choice by upland farmers. Promoting the switch to AF system and the adoption of soil conservation is of great importance to reducing soil erosion and sustaining development in the uplands. However, it is a very challenging task.