Effect of DDT,fauna and flooding on microbial growth in soil

Abstract

Laboratory experiments were conducted to determine the effect of DDT, fauna and flooding on microbial growth in a sandy loam. Results indicated that soil microorganisms can tolerate the presence of DDT. Earthworms singly or in combination with springtails affected the average population of fungi in the DDT‐untreated samples and of aerobic bacteria in the DDT‐treated soils. Soil animals did not appear to have any effect on the populations of anaerobic bacteria. However, waterlogging brought about a decrease in aerobic bacteria and fungal populations, and an increase in anaerobic bacteria in both soils.     

Amazonian freshwater habitats experiencing environmental and socioeconomic threats affecting subsistence fisheries

Matching the trend seen among the major large rivers of the globe, the Amazon River and its tributaries are facing aquatic ecosystem disruption that is affecting freshwater habitats and their associated biodiversity, including trends for decline in fishery resources. The Amazon’s aquatic ecosystems, linked natural resources, and human communities that depend on them are increasingly at risk from a number of identified threats, including expansion of agriculture; cattle pastures; infrastructure such as hydroelectric dams, logging, mining; and overfishing. The forest, which regulates the hydrological pulse, guaranteeing the distribution of rainfall and stabilizing seasonal flooding, has been affected by deforestation. Flooding dynamics of the Amazon Rivers are a major factor in regulating the intensity and timing of aquatic organisms. This study’s objective was to identify threats to the integrity of freshwater ecosystems, and to seek instruments for conservation and sustainable use, taking principally fish diversity and fisheries as factors for analysis.     

在线超声作用下流化床膜生物反应器的膜污染机制

在流化床膜生物反应器中引用在线超声技术来控制膜污染,考察了在线超声对污泥混合液特性的影响,探讨了在线超声作用下的膜污染机制。结果表明：在线超声流化床膜生物反应器的跨膜压差（TMP）增长速度明显慢于普通流化床膜生物反应器,可延长膜清洗周期约51％。在线超声作用下,污泥平均粒径降低约70μm,污泥胞外聚合物（EPS）含量增加（14±5）mg／g,混合液溶解性微生物产物（SMP）有所降低;同时,在线超声使得污泥浓度和混合液粘度降低,从而改善了混合液的过滤性,有助于膜污染的控制。分析表明,在线超声能够减少膜表面不可逆污染的发生,膜的主要污染机制为泥饼层污染。     

Selective removal of diclofenac from contaminated water using molecularly imprinted polymer microspheres

A molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template. Binding characteristics of the MIP were evaluated using equilibrium binding experiments. Compared to the non-imprinted polymer (NIP), the MIP showed an outstanding affinity towards DFC in an aqueous solution with a binding site capacity (Q_max) of 324.8 mg/g and a dissociation constant (K_d) of 3.99 mg/L. The feasibility of removing DFC from natural water by the MIP was demonstrated by using river water spiked with DFC. Effects of pH and humic acid on the selectivity and adsorption capacity of MIP were evaluated in detail. MIP had better selectivity and higher adsorption efficiency for DFC as compared to that of powdered activated carbon (PAC). In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance, which is a definite advantage over single-use activated carbon.     

戈尔膜过滤器在采油废水处理中的应用

"聚合物驱"采油技术在提高原油采收率的同时也产生了大量的采油废水。传统处理工艺多采用核桃壳过滤,处理效果不理想。戈尔膜过滤器因其具有效率高、运行稳定、易于维修以及全自动化控制等优点,更适合现行处理工艺的改造需求,在采油废水处理中避免了一些生物与化学处理所引起的二次污染等问题,具有较高的推广价值。     

铁系混凝剂处理含聚合物油田污水的研究

本文探讨了含聚合物油田污水的组成、胶体结构,研究了铁系混凝剂处理该污水的条件和酸度对处理过程的影响。     

用透射电镜研究聚硅酸硫酸铁混凝剂的形态

由水玻璃、硫酸和硫酸铁制备聚硅酸硫酸铁（ＰＦＳＳ）混凝剂,用透射电镜观察ＰＦＳＳ的形态,研究了ＰＦＳＳ的形态随硅酸聚合时间,ＳｉＯ２／Ｆｅ摩尔比和熟化时间的变化。结果表明,硅酸聚合时间,ＳｉＯ２／Ｆｅ摩尔比及熟化时间对ＰＦＳＳ的形态有较大的影响。     

Towards a spatial information infrastructure for flood management in The Netherlands

The immense value of a geographic information system for flood control has been experienced by the decision-markers of the Dutch province of Gelderland during the flood of the Rivers Meuse (Maas) and Waal in January 1995. Super-imposing different ‘data layers’, GIS-experts could detect the weak parts in the dikes and generate and evacuation plan. Shortcomings within the organization were experienced as well: important data could not be retrieved, and the coordination of efforts by the different governmental departments and institutions was not optimal. To overcome these shortcomings and to optimize the modelling process, a spatial decision support system (SDSS) is being proposed, aggregating several models, heuristic and procedural, into integrated software tools. As becomes clear from two cases of flood control described, ‘emergency managers’ should be able to communicate about spatial data available and have access to selected spatial data. In order to improve communication between data sources, data processing and the use of relevant spatial data in GISs, a new ‘Spatial Information Infrastructure’ (SII) needs to be developed. This requires both technical and organizational solutions and standards. Proper documentation of the data will allow the GIS-experts to more quickly find, store, update and reuse the data. A range of ‘metadata’ services exist documenting data sets, typically limited by thematic or national boundaries. There are no standards in common practice for structuring and classifying spatial information. The user of spatial information cannot easily browse across Web-sites and compare products from different suppliers. Even, if the search has been successful, the user all too often has to face a complex process of negotiation, and highly technical data integration issues. A consortium of European GIS-experts has addressed these problems and launched the ‘European Spatial Metadata Infrastructure’ (ESMI) project with the objective to link existing and future metadata systems using Internet.     

Assessment of Global Weather Disasters in 2000

1 Climate background Although the La Nina event caused the decrease of the mean temperature in the tropical regions of the Pacific Ocean, the year 2000 had remained one of the hottest since 1860 when records of the global mean temperature began. The temperature in the areas to the north of 20扤 from December 1999 to November 2000 marked the second warmest in history. The mean temperature of the global surface in 2000 was 0. 60C above the average during the period 1880?999, and was close to …     

高分子材料服役寿命预测方法最新进展

高分子材料在使用过程中,由于受各种环境因素作用,会逐步出现性能下降,甚至丧失使用价值的老化现象,不仅造成资源浪费,更形成安全隐患。为应对老化问题,研究者以各种宏观性能或微观结构、组份的变化来表征老化过程,针对高分子材料的环境适应性开展了大量研究工作,并在此基础上提出了不同的老化机理和服役寿命预测方法。从高分子材料老化过程表征的视角,综述了近年来高分子材料服役寿命预测方法的最新进展。