微生物法和微生物生态法的评价和选用

微生物法和微生物生态法作为生物治理方案的两大类型，已日益受到环保工作者的重视。这两种类型的治理方法各有特点，各有利弊。如何选择使用？主要取决于污染场所中污染形成的时间长短、污染程度、污染物浓度、污染物中是否含有污水、是否需要快速治理等。应明确指出的是，采用生物治理法虽可在多种情况下大大降低污染物的浓度，但从长远来看，还不能单纯依靠降低污染物的排放浓度，而是应从低浓度污染物对人和环境产生的长期影响着眼，制定出一套治理标准，这样才能准确评价生物治理技术在环境保护中所起的真正作用。     

UNCERTAINTY ANALYSIS OF BMP EFFECTWENESS FOR CONTROLLING NITROGEN FROM URBAN NONPOINT SOURCES1

ABSTRACT: The effectiveness of urban Best Management Practices (BMPs) in achieving the No-Net-Increase Policy (NNTP), a policy designed to limit nonpoint nitrogen loading to Long Island Sound (US), is analyzed. A unit loading model is used to simulate annual nitrogen exported from the Norwalk River watershed (Connecticut) under current and future conditions. A probabilistic uncertainty analysis is used to incorporate uncertainty in nitrogen export coefficients and BMP nitrogen removal effectiveness. The inclusion of uncertainty in BMP effectiveness and nitrogen export coefficients implies that additional BMPs, or BMPs with a greater effectiveness in nitrogen removal, will be required to achieve the NNIP. Even though including uncertainty leads to an increase in BMP implementation rates or BMP effectiveness, this type of analysis provides the decision maker with a more realistic assessment of the likelihood that implementing BMPs as a management strategy will be successful. Monte Carlo simulation results indicate that applying BMPs to new urban developments alone will not be sufficient to achieve the NNIP since BMPs are not 100 percent effective in removing the increase in nitrogen caused by urbanization. BMPs must also be applied to selected existing urban areas. BMPs with a nitrogen removal effectiveness of 40–60 percent, probably the highest level of removal that can be expected over an entire watershed, must be applied to at least 75 percent of the existing urban area to achieve the NNIP This high rate of application is not likely to be achieved in urbanized watersheds in the LIS watershed; therefore, additional point source control will be necessary to achieve the NNIP     

农田塑料地膜污染及防治

分析了农田塑料地膜污染现状及残留对土壤产生的不良影响：降低土壤渗透性、减少土壤含水量、削弱耕地抗旱能力,造成农作物减产,破坏自然景观和造成环境污染。提出了防治措施：加强环保宣传教育,制定奖惩政策,加大残留地膜的回收力度;制定农膜残留和厚度标准;推广可降解塑料薄膜;采用适时揭膜技术;制定经济政策,加强残留地膜回收后的利用。     

室内空气污染净化研究进展

介绍了室内空气污染的现状、特点及其危害,指出了室内空气污染的主要污染源和污染物。综述了各种室内空气污染净化技术,并介绍了各种技术的优缺点。本文最后对室内空气污染净化的发展前景进行了展望。     

企业可持续发展评价指标体系的选定原则及构建框架

为了制定企业可持续发展的战略决策,须制定可持续发展的指标体系,并依据这一体系对数据和资料进行收集、整理和分析,从而确定可靠而有效的政策方针。文中论述了可持续发展指标体系的定义、选定标准、原则和可持续发展的评价指标体系,提出了压力-状态-响应框架模型以及不同层次的指标体系框架。该指标体系分为总体层、系统层、状态层、变量层和要素层五个等级。对于持续发展的表征指标及对目前发展的可持续性评估,还需要长时间和切合实际的探讨。     

石油污染土壤生物修复技术的研究进展

目前对石油污染环境的治理方法有物理法、化学法和生物修复三种类型。文章综合论述了国内外对石油污染土壤的几种微生物修复方法,分别介绍了利用植物、动物及微生物进行治理的修复技术。在我国,对于石油污染的治理应更多地采用低成本、无污染、高效率的生物治理技术。     

Quantifying and Evaluating Ecosystem Health: A Case Study from Moreton Bay, Australia

As part of the program monitoring the ecosystem health of Moreton Bay, Queensland, Australia, we developed a means for assessing ecosystem health that allows quantitative evaluation and spatial representations of the assessments. The management objectives for achieving ecosystem health were grouped into ecosystem objectives, water quality objectives, and human health objectives. For the first two groups, aspects of the ecosystem (e.g., trophic status) were identified, and an indicator was chosen for each aspect. Reference values for each indicator were derived from management objectives and compared with the mapped survey values. Subregions for which the indicator statistic was equal to or better than the assigned reference value are referred to as “compliant zones.” High-resolution surface maps were created from spatial predictions on a fine hexagonal grid for each of the indicators. Eight reporting subregions were established based on the depth and predicted residence times of the water. Within each reporting subregion, the proportion that was compliant was calculated. These results then were averaged to create an integrated ecosystem health index. The ratings by a team of ecosystem experts and the calculated ecosystem health indices had good correspondence, providing assurance that the approach was internally consistent, and that the management objectives covered the relevant biologic issues for the region. This method of calculating and mapping ecosystem health, relating it directly to management objectives, may have widespread applicability for ecosystem assessment.     

Assessment of Soil Erodibility Indices for Conservation Reserve Program Lands in Southwestern Kansas Using Satellite Imagery and GIS Techniques

The soil erodibility index (EI) of Conservation Reserve Program (CRP) lands, which was the major criterion for CRP enrollment, was assessed for six counties in southwestern Kansas using USGS seamless digital elevation model data and Geographical Informational System techniques. The proportion of land areas with EI values of 8 or lower was less than 1% of the entire study area and most of the land areas (72.5%) were concentrated on EI values between 8 and 24. Although land acreage with EI values of 24 or higher decreased dramatically, the proportion of CRP lands to the other land-use types did not change much from low to high EI levels. The soil EI and physical soil characteristics of the CRP lands were compared to those of other land-use types. In general, the mean EI values of the land-use types were strongly correlated with physical soil properties, including organic matter content, clay content, available water capacity, permeability, and texture. CRP lands were compared in detail with cropland in terms of their soil characteristics to infer the pivotal cause of the land transformation. Although there was no significant statistical difference in EI between cropland and CRP soils, soil texture, soil family, and permeability were statistically different between the two. Statistical analyses of these three variables showed that CRP soils had coarser texture and higher permeability on average than cropland soils, indicating that CRP lands in the study area are drier than cropland soils. Therefore, soil moisture characteristics, not necessarily soil erosion potential, might have been the key factor for CRP enrollment in the study area.     

INFLUENCE OF AGRICULTURAL PRACTICES ON WATER QUALITY IN NEBRASKA: A SURVEY OF STREAMS,GROUNDWATER, AND PRECIPITATION1

ABSTRACT Rainfall, stream flow and groundwater have been sampled systematically throughout Nebraska since 1970 and analyzed for mineral N and P and the character of any sediments contained. Fallout N and P in rainfall ranges from 5–14 pounds N and 1 pounds P/A/yr, increasing from west to east across the state with increasing rainfall. The amount of NH4-N is essentially double that of NO₃-N. The mean concentration of 2ppm N in rainfall is four times the mean N concentration of streams, demonstrating a substantial depolluting action of soils and growing crops. Where nutrient levels of streams are elevated, cause can usually be traced especially to industrial, sewage or livestock waste intrusion and not to crop production practices. The only significant quantity of nutrient N and P induced by cultivation is that accompanying sediments from eroded fields. The P content of Nebraska groundwater has remained essentially constant during the past 10 years while average NO₃-N has increased slightly, a period during which farmer fertilizer use quadrupled. During the same time, irrigation acreage has increased by 50%, livestock numbers by 30%, with corresponding growth in human population and attendant industries. Indications are that irrigation practice has contributed more than any other factor to the small increase in groundwater NO3-N recorded. Individual cases do exist where groundwater NO₃-N has increased substantially, especially in areas of intensive irrigation agriculture on very sandy soils and elsewhere with irrigation development in the proximity of ancient NO₃-N deposits in mantlerock above the water table.     

DIGITAL SIMULATION OF THE EFFECT OF THERMAL DISCHARGE ON STREAM WATER QUALITY1

A modified transient version of the Streeter-Phelps model along with the energy balance equation is employed to analyze the effects of waste heat discharge from power plants on stream water quality. Analysis is also made to examine the effects of the upstream water quality and stream velocity on the downstream DO concentration level. The resulting coupled nonlinear hyperbolic partial differential equations representing the energy, BOD and DO concentrations are solved by the method of characteristics and simulated on a digital computer. Final numerical results indicate that the allowable quantity of thermal discharge does heavily depend on the upstream quality.