超声-双氧水和亚铁离子体系处理含酚废水研究

在实验装置上对超声-双氧水和亚铁离子体系联合处理含酚废水进行了实验研究。主要考察了废水初始pH值、初始双氧水浓度、超声功率、反应时间等因素对酚去除率的影响。实验结果表明：超声辐射可以在双氧水和亚铁离子体系氧化过程中起加速反应的作用，而且随着超声功率的增大，加速反应的能力增强；实验条件下废水初始pH值为4～6．8，初始双氧水浓度为140mg／L时酚去除效果最佳；超声-双氧水和亚铁离子体系处理含酚废水过程中苯酚的降解规律符合表现一级反应。     

吸附-双催化氧化降解苯胺、硝基苯废水

苯胺、硝基苯废水利用吸附树脂吸附后,再利用过氧化氢作氧化剂,在亚铁离子和紫外光的双催化下氧化降解。通过对亚铁离子浓度、过氧化氢浓度等因素对光降解影响的考察,结果表明,在实验条件下,本氧化体系对苯胺、硝基苯废水有明显的降解效果,苯胺、硝基苯废水经该体系处理12h后,去除率最高分别达到99.7%和95.3%。     

提高水中氨氮测定精准度的研究

纳氏试剂光度法是污水中氨氮测定广泛采用的方法,文章通过实验分析讨论实验室环境、水样预处理、酒石酸钾钠和显色温度、显色时间、pH值等实验条件对氨氮测定精准度的影响。实验结果表明:改善实验室环境,在20²5℃、显色15min、显色后pH值为13的条件下,用滤膜代替滤纸,向酒石酸钾钠中加入NaOH煮沸浓缩定容能显著提高氨氮测定的精准度。     

钴-TAN-非离子型表面活性剂体系的分光光度研究及其应用

钴的分光光度测定常用的显色试剂有亚硝基红盐、亚硝基甲苯酚、PAR、[2]、5 cl PADAB、[3]、DPPI、[4]、亦有采用多元络合物的[5]。中川元吉等研究了1(2噻唑偶氮)2萘酚(简称 TAN)与一些金属离子的反应,[6]提出在 PH 4～10,TAN 与 Co~(2+)生成组成     

气体二氧化氯对图书馆阅览室书刊表面消毒效果的探析

文章采用高纯度气体二氧化氯作为消毒剂,以图书馆阅览室书刊表面作为研究对象,采用梅花点分布采样法对图书馆阅览室书刊表面进行取样,平板涂布法对采集到的病原微生物进行菌落计数。通过研究在不同浓度、不同杀菌时间、不同杀菌时间段条件下,气体二氧化氯对图书馆阅览室书刊表面的消毒效果,结果表明:气体二氧化氯浓度为0.6mg/m~3,杀菌时间为60min,杀菌时间段为20:00~21:00时,可以达到对书刊表面杀菌消毒的效果。     

注空气低温氧化辅助热采废水处理

对注空气低温氧化辅助热采废水的处理进行实验研究,先进行混凝处理,再分别采用Fenton氧化法和二氧化氯氧化法对废水氧化处理。结果表明后者效果较好,二氧化氯最佳投加量为300 mg/L,催化剂活性炭-Ni投加量为2.5 g/L,反应2 h,COD_(Cr)降低至129.14 mg/L,去除率达到95.29%,出水无色透明。二氧化氯氧化法适合于海上油田注空气低温氧化辅助热采废水的处理。     

钴-TAN-非离子型表面活性剂体系的分光光度研究及其应用

钴的分光光度测定常用的显色试剂有亚硝基红盐[1]、亚硝基甲苯酚[1]、PAR、[2]、5 cl PADAB、[3]、DPPI、[4]、亦有采用多元络合物的[5]。中川元吉等研究了1-(2 噻唑偶氮)2-萘酚(简称TAN)与一些金属离子的反应,[6]提出在PH 4～10,TAN与Co~(2+)生成组成2∶1的红色络合物,Σ580nm=3.8×10~4,但未见用于具体样品分析,且需用氯仿萃     

甲醛法测定空气中二氧化硫影响因素分析

甲醛吸收-副玫瑰苯胺分光光度法是测定环境空气中的二氧化硫的常用方法,该方法具有灵敏度高、选择性好等优点,但在实验分析过程中发现,该方法对实验室环境条件、反应条件、试剂的质量和实际操作要求严格。文章通过对影响空白值及检测结果的显色温度、显色时间、实验试剂、样品的采集及保存等关键因素进行实验分析,使校准曲线斜率和试剂空白吸光度值在给定的检测条件下满足检测方法标准的要求,为提高甲醛法测定空气中二氧化硫测量结果的准确性提供参考。     

硫酸盐生物还原的限制性生态因子的影响研究

利用厌氧颗粒污泥对烟气中SO2吸收生成的硫酸盐或亚硫酸盐废水进行处理,考察起始SO4^2-质量浓度、初始COD／SO4^2-、初始pH、接种污泥质量、亚铁离子等限制性生态因子对硫酸盐还原的影响。结果表明：在起始SO4^2-质量浓度800mg／L,初始COD／SO4^2-为3．0,pH值为7．0,接种污泥质量为31．10gVSS／L,添加亚铁离子的条件下,进行半连续试验,硫酸根去除率可迭70％。表明在COD／SO4^2-较低的条件下,各生态因子综合作用下,硫酸盐还原可得较好效果。     

草木灰对亚甲基蓝的吸附研究

本实验目的是研究草木灰对吸附亚甲基蓝的去除效果,探讨了亚甲基蓝初始量、吸附时间、pH值等对吸附效果的影响,并运用伪一级、伪二级反应动力学模型和Laugmuir、Freundlich等温线模型进行拟合。结果表明,草木灰对亚甲基蓝溶液的吸附在5 min~30 min速率比较快,约在65 min内达到吸附平衡,pH越大越有利于吸附,浓度在5mg/L时草木灰对亚甲基蓝的吸附最佳。与伪二级动力学曲线模型拟合效果较好,由Laugmuir等温线模型计算得出理论最大吸附容量Qm为2.275 mg/g,吸附性能优异。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States

In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.     

Journalists' views of advertiser pressures on agricultural news

All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.     

MANGANESE CYCLE IN IMPOUNDMENT WATER

Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.     

Provincial development plans in Zimbabwe: an analysis of their content,structure and methodology

Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.