渭河流域生态环境对野鸭数量分布的影响

环境是动物生存的基础，人类的活动对环境所造成的影响，直接导致动物种群数量的变动。通过渭河咸阳段气候、水质、水域面积、植物等环境因素的改变对野鸭数量分布影响的调查，表明环境的恶化导致了动物的生存受到威胁，数量减少，分布区域缩小。随着环境保护意识的增强，渭河流域的水土流失，水质污染、退耕还草等环境问题逐渐得到解决，动物的生活环境不断得到改善，其种群数量、分布范围随之增加。     

车用三效催化剂的研究进展

三效催化剂是机外治理机动车尾气污染最常采用的有效方法，车用三效催化剂已发展到第4代。目前车用三效催化剂的研究主要集中在：开发稀燃型三效催化剂和紧耦合三效催化剂及发展三效催化剂低温冷起燃技术等。国内应以稀土添加少量贵金属的三效催化剂为主要研究方向，开发适合我国现状的车用净化催化剂技术。     

露天深孔爆破环境污染的危害与防治

在全面分析爆破所带来的地震效应、噪声以及废气等污染的同时，结合某矿山生产爆破的具体情况，提出了些防治爆破环境污染的措施和建议。     

GROUND WATER NITRATE REDUCTION IN GIANT CANE AND FOREST RIPARIAN BUFFER ZONES1

ABSTRACT: Ground water contamination by excess nitrate leaching in row‐crop fields is an important issue in intensive agricultural areas of the United States and abroad. Giant cane and forest riparian buffer zones were monitored to determine each cover type's ability to reduce ground water nitrate concentrations. Ground water was sampled at varying distances from the field edge to determine an effective width for maximum nitrate attenuation. Ground water samples were analyzed for nitrate concentrations as well as chloride concentrations, which were used as a conservative ion to assess dilution or concentration effects within the riparian zone. Significant nitrate reductions occurred in both the cane and the forest riparian buffer zones within the first 3.3 m, a relatively narrow width. In this first 3.3 m, the cane and forest buffer reduced ground water nitrate levels by 90 percent and 61 percent, respectively. Approximately 40 percent of the observed 99 percent nitrate reduction over the 10 m cane buffer could be attributed to dilution by upwelling ground water. Neither ground water dilution nor concentration was observed in the forest buffer. The ground water nitrate attenuation capabilities of the cane and forest riparian zones were not statistically different. During the spring, both plant assimilation and denitrification were probably important nitrate loss mechanisms, while in the summer nitrate was more likely lost via denitrification since the water table dropped below the rooting zone.     

Comparing Environmental Conditions Using Indicators of Pollution Hazard

/ Land use/land cover classifications for 1973 and 1991, derived from the interpretation of satellite imagery, are quantified on the basis of biophysical land units in a study area in southeastern Australia. Nutrient export potentials are estimated for each land unit based on their composition of land use/land cover classes. Spatial and temporal comparisons are made of the land units based on the calculated pollution hazard indicators to provide an insight into changes in the state of the environment and the regional significance of land use changes. For example, one ecosystem, unique to the study, showed a large increase in pollution hazard over the study period as a manifestation of an 11-fold rise in cleared area and an expansion of cropping activities. The benefits to environmental management in general are discussed.KEY WORDS: Land cover change; Nutrient export; Environmental condition; Pollution hazard; Agricultural pollution; Nonpoint source pollution; Diffuse pollution; Environmental degradation     

A Sensitivity Analysis of Nitrogen Losses from Dairy Farms

International attention has focused on agricultural production systems as non-point sources of pollution affecting the quality of streams, estuaries and ground water resources. The objective of the current study was to develop a model of nitrogen management on the dairy farm, and to perform sensitivity analyses in order to determine the relative importance of manipulating herd nutrition, manure management and crop selection in reducing nitrogen (N) losses from the farm. The importance of the method of N input to the farm (purchased feed, legume fixation, inorganic fertilizer, imported manure) was investigated, and the potential to reduce N losses from dairy farms was evaluated. Nitrogen balance equations were derived, and related efficiency coefficients were set to reference values representing common management practices. Total farm N efficiency (animal product N per N input), and N losses per product N were determined for different situations by solving the set of simultaneous equations. Improvements in animal diet and management that increase the conversion of feed N to animal product by 50% would increase total farm N efficiency by 48% and reduce N losses per product by 36 to 40%. In contrast, reducing losses from manure collection, storage and application to improve the percentage of manure N that becomes available in soil by 100% would only improve total farm N efficiency by 13% and reduce total N losses by 14%. Selecting crops and management that can use soil nutrients 50% more efficiently would improve total farm efficiency by up to 59% and reduce N losses by up to 41% depending on the predominant nitrogen sources to the farm. Legume production would reduce N losses per product compared with non-legumes. There was more than a five fold difference in N losses per animal product N between the most extreme scenarios suggesting considerable opportunity to reduce N losses from dairy farms.     

洗涤法处理含油土壤的研究

研究了用洗涤法处理含油土壤，考察了洗涤剂种类与浓度、洗涤温度、液固比、洗涤时间、表面活性剂、洗涤液直接循环使用次数对洗涤效果的影响，结果表明：当混合减浓度为10000mg／L、洗涤温度为70℃、液固比2：1、洗涤时间20min时，可将含油量为30％的土壤洗至残油率仅为0．3％左右。OP、EL型表面活性剂的加入对洗涤效果没有改善，特别有意义的是洗涤液能够直接循环使用而对洗涤效果基本无影响，这不仅能够减少用水量，还可以大大减少废水的排放量，降低操作费用及废水处理费用。该洗涤法不涉及物质的相变过程，混合碱由廉价的无机碱和无机盐组成，故能量消耗低，处理费用也低，且洗脱下来的原油可回收。     

环境医学：人类生存发展战略的大课题

文章用大量翔实数据，分析论证：人类由于淡化环境意识，坚持急功近利的片面发展观，造成整个地球环境质量正在全面下降和恶化，全球已有１／５的人口受到环境污染之害的基点上，作者提出了只有跳出以自我生存为中心的狭隘圈，确立发展环境医学为主体的预防医学战略，并提示要遵循中国古代强调的“天人合一”论概念和钱学森提出的“开放的巨系统方法论”在当代科技领域进行“天地生人巨系统的综合集成研究”，树立“天地与我并生，万物与我同运”的自然生态观，为创建“生物心理社会自然”为模式的全科新医学，这是实现２１世纪“人类健康工程”的开拓性目标。     

岷江干流（成都段）水体污染防治对策研究

本文通过对岷江干流（成都段）地表水和地下水的综合研究，分别提出了地表水污染防治对策和地下水水质防护措施，划分出了地表水防治不同时期的目标以及地下水开采管理目标。     

河流水质灾害中的S—P方程稳态分析和临界氧亏计算

污染物对水环境的影响主要发生在枯水期，此时水流状态处于稳态．Streeter－phelps（S－P）方程能预测简单稳态条件下的水质状况，并具有较高的计算织亏的精度．