Biodegradation of chlorpyrifos by either single or combined cultures of some soilborne plant pathogenic fungi

Abstract

Biodegradation of chlorpyrifos was studied in liquid culture media amended with either single or combined eight different plant pathogenic fungi isolated from the continuous cropping wheat fields. The average recovery of chlorpyrifos from the liquid media was found to be 86.1%. The detection limit of chlorpyrifos by the analytical method used was 19 ppb. Data showed that the growth of mixed fungi at concentrations up to 200 ppm of chlorpyrifos was higher than in the control treatment. Chlorpyrifos concentrations declined in the medium of combined fungi more than it did in the medium of any single fungus with increase in the incubation period. The amount of chlorpyrifos recovered was 79.8 ppm (39.9%) in the combined fungal cultures after 21 days. However, those recovered from the media of Fusarium graminearum, F. oxysporum, Rhizoctonia solani, Cladosporhim cladosporiodes, Cephalosporium sp., Trichoderma viridi, Alternaria alternata, and Cladorrhinum brunnescens, ranged from 48.0 to 74.8%. The half‐life value (T_1/2) for chlorpynfos was 15.8 day in the medium amended with mixed fungi. However, for the single cultures it ranged from 19.3 to 33.0 day.     

燃煤电厂SCR烟气脱硝技术的研究

选择性催化还原(SCR)技术是目前燃煤电厂应用最多且最成熟的烟气脱硝技术.介绍了SCR烟气脱硝技术的化学反应机理、工艺流程等,重点对影响SCR法脱硝效率的多种因素进行了深入分析,并对SCR技术的未来研究方向进行了展望.     

2010年7-8月国内环境事件

简要统计了2010年7-8月国内发生的各种环境事件138起,包括沙尘天气4起,污染事件21起,地震40起,山体滑坡和泥石流38起,旱灾3起以及其他自然灾害32起.     

Sorption of alkylphenols on Ebro River sediments: comparing isotherms with field observations in river water and sediments

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f_OC) ranging from 0.0035 to 0.082 g_OC g⁻¹. All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations.     

基于连通法的甲烷简化机理构筑研究

采用连通法，针对甲烷复杂反应机理，成功地进行了不同水平的机理简化研究。通过建立组分依赖关系的正规化Jacobian矩阵，精确地查明了燃烧组分之间的耦合关系，分别构造出仅包含重要化学路径的两个动力学简化模型，获得的简化机理分别包含227和138个反应，分别涉及39和26种组分。通过对层流预混火焰结构的模拟，所得简化机理和原详细反应动力学机理关于火焰结构的计算吻合很好，计算结果显示，两个简化机理具有较高的模拟精度。     

Production of magnesium from desalination brines

Recovery of minerals from desalination brines is considered to be a very attractive source of minerals. It is usually recommended for reducing fresh-water production cost and minimizing waste disposal. This paper discusses the production of magnesium from a Saudi desalination brine with reference to the Arabian Gulf conditions.     

A geomorphic framework for developing a sustainable greenery programme in arid environments

Summary This paper attempts to demonstrate that the study of geomorphology can provide a useful framework for understanding the natural processes and factors that are critical for the development of ecologically sustainable and economically viable greenery projects in the desert and arid environments.The surface of Kuwait was subdivided into 15 geomorphic zones and each zone was assessed in terms of its potentiality for establishing greenery activities. The assessment considered the implications of relief, soil type and fertility, aeolian processes, sand encroachment and presence or absence of indurated bedrocks and pavements for the greenery plan of Kuwait. Accordingly, areas with the most favourable conditions for revegetation were identified and strategies for enhancing the conservation value and sustainability of the greenery programme were outlined.The study pointed out that while the adopted approach provided useful environmental guidelines at the planning level, further investigations would be required, at the project level, if the principles of ecologically sustainable development were to be fully incorporated within such a large scale greenery undertaking.Dr Dhia Al Bakri is a Lecturer in Environmental Management at the Orange Agricultural College, University of Sydney, Australia. He worked as a Research Scientist for the Kuwait Institute for Scientific Research from 1980 to 1990. During that time Dr Al Bakri undertook a wide range of studies and research projects within the context of Environmental and Earth Sciences.     

Reengineering the environmental function: Making tough decisions

The process outlined in this article includes tools that can be used to achieve the efficiencies necessary for effective reengineering. This process can help ensure that management will not just cut out resources and expect the same services performed the same way. Environmental professionals will be able to show in black and white what their objectives are and what will and will not be done as a result of reengineering.     

AN ECONOMIC ASSESSMENT OF GROUND WATER RECHARGE IN THE TUCSON BASIN1

ABSTRACT: Bringing water from Colorado River via the Central Arizona Project was perceived as the sole solution for Tucson Basin's water problem. Soon after Central Arizona Project's water arrived in Tucson in 1992, its quality provoked a quarrel over its use for potable purposes. A significant outcome of that quarrel was the enactment of the 1995 Proposition 200. The Proposition 200 precludes the use of Central Arizona Project's water for potable purposes, unless it is treated. Yet, it encourages using it for non‐potable purposes and for replenishing the Tucson aquifer through recharge. This paper examines the economic issues involved in utilizing Central Arizona Project's water for recharge. Four planning scenarios were designed to measure and compare the costs and benefits with and without Central Arizona Project's water recharge. Cost‐benefit analysis was utilized to measure recharge costs and benefits and to derive a rough estimate of cost savings from preventing land subsidence. The results indicate that the institutional requirements can be met with Central Arizona Project's water recharge. The economic benefits from reducing pumping cost and saving groundwater are not economically significant. Yet, when combining the use of Central Arizona Project's water for recharge and non‐potable purposes, it demonstrates positive net economic benefits.     

高效藻类塘在污水处理中的研究及应用前景

高效藻类塘是在传统稳定塘的基础上发展起来的极具推广价值的污水处理技术。它具有停留时间短,水深浅,对氮磷的去除效果好的特点。本文阐述了高效藻类塘的特点、影响因素及去除机理,并展望了其应用前景。