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961.
The retention values of two herbicides, chlorotoluron and isoproturon, in five Mediterranean soils were assessed by two different approaches, a dynamic method, using a batch technique (BT) and a static method, using a soil saturated paste (SP). The SP method led in all cases to lower herbicide sorption when compared with BT, although pesticide distribution constants from both methods were linearly related for the set of used soils (R2 ? 0.99) showing that both methods similarly reflected the behaviour of the different soils. Low-quality water, evaluated by employing recycled urban wastewater, did not modify herbicide sorption when compared with high quality water, in any soil and with any method. 相似文献
962.
963.
Doyeli Sanyal Anita Rani Samsul Alam 《Journal of environmental science and health. Part. B》2013,48(7):706-716
Quick, simple and efficient multi-residue analytical methods were developed and validated for the determination of organophosphorous insecticides from polished and cooked rice. Polished rice was extracted using a simple, automated technique namely accelerated solvent extraction (ASE) using dichloromethane as the extraction solvent. Cooked rice was extracted with acetone and cleaned up using dispersive-solid phase extraction (D-SPE) technique. The single step extraction method adopted for polished rice using accelerated solvent extractor provided satisfactory recovery for eight organophosphorus pesticides (OPPs) which ranged from 85.5–116.7%; 90.0–110.3% and 93.5–118.8% at 1, 5 and 10 limit of quantification (LOQ) levels, respectively. The recovery of cooked rice was in the range of 74–124%; from 75–100% and from 73–87% for 1, 5 and 10 level of fortification, respectively. The total uncertainty was evaluated, taking four main independent sources viz., weighing, purity of the standard, GC calibration curve and repeatability under consideration. The expanded uncertainty was found to be in the range of 5–20%. 相似文献
964.
双波长紫外吸收法有机废水COD测量技术与仪器设计 总被引:1,自引:0,他引:1
紫外吸收法直接测定有机废水COD是一种无需化学试剂、无样品前处理、无二次污染的绿色无损检测技术,但在实际应用中发现,有机废水中的悬浮物对测量结果产生较大影响.以实际废水水样为例,详细阐述了双波长紫外吸收法测量有机废水COD的操作方法及其消除悬浮物干扰的原理,并介绍了运用该技术设计开发的COD在线测量仪器.该仪器采用嵌入式计算机系统实时采集和处理数据,根据实际废水在双波长测量条件下的有效紫外吸光度快速推算出其COD值,具有快速、准确、无污染的特点. 相似文献
965.
Addressing landscape-level threats to stream fishes such as habitat and hydrological alterations requires adequate watershed-level
species inventories. Where watershed-level ichthyofaunal surveys are prohibitively expensive, existing (historical) data sources
may provide an option for compiling species lists. However, it is critical that managers consider potential biases or limitations
of species lists compiled from existing data. Here we assess the suitability of species lists compiled from existing data
sources for making watershed-level fish management and conservation decisions. For nine Great Lakes watersheds, we developed
existing species lists by compiling all available federal and state agency and museum fish survey data. We then compared the
size and species composition of existing species lists to current species lists compiled from intensive field surveys, conducted
in 2002, of the same watersheds. Species lists compiled from commonly available existing data sources, such as state and federal
agency and museum data, missed many species detected during our 2002 field surveys. In most watersheds, more than 10 species
were missed (range 5–21) on existing lists. Sampling over multiple years and seasons increased the size of both current (field)
and existing species lists. Existing species lists compiled from surveys conducted over multiple years and seasons included
an average of 15 species not captured during the 2002 field surveys. However, such multiyear existing datasets are rare and
not available for many watersheds. In addition, species lists compiled from older existing surveys (e.g., before 1984) did
not accurately represent current species composition of the watersheds and our results indicate several apparent misidentifications
or errors on these lists. Lastly, while most game species were detected on existing lists, migratory species and recently
introduced species were commonly missed on these lists. We conclude with recommendations for using existing data for watershed-level
stream fish management and conservation decisions. 相似文献
966.
《Disasters》2000,24(1):80-85
Books reviewed: John Twigg and Mihir R. Bhatt, eds, Understanding Vulnerability Joachim von Braun, Tesfaye Teklu and Patrick Webb, Famine in Africa: Causes, Responses, and Prevention C. Emdad Haque, Hazrads in a Fickle Environment: Bangladesh Walter Gillis Peacock, Betty Hearn Morrow and Hugh Gladwin, eds, Population and Food: Global Trends and Future Prospects Roy Gutman and David Rieff, eds, Crimes of War: What the Public Should Know 相似文献
967.
An overview of systems analysis methods in delineating environmental quality indices 总被引:1,自引:0,他引:1
Environmental quality indices (EQIs) have been developed for a variety of purposes ranging from enforcement of environmental standards, to analysis of trends of environmental degradation or improvement, to scientific research. EQIs currently in use are not organized within an integrated framework and thus it has been difficult to analyze adequately complex, multidisciplinary, large-scale, global phenomena. In this paper we compare four different approaches to developing EQIs within a systems perspective. Our analysis suggests that: (1) non-linear regression models that represent an ecosystem's response to different impacts within a stress-response framework (method of response functions) are useful tools for analysis of environmental data; (2) non-equilibrium thermodynamics models based on the concept of exergy, which represents the free energy a system possesses in relation to its environment, provide a common basis for representing many aspects of ecosystem development and response to environmental impacts as a single measure; (3) diagram models based on the concept of emergy, which represents both environmental values and economic values with a single measure, provide a common basis for integrating economic development and environmental protection values into one index; and (4) complex systems simulation models based on general systems theory, which use the methodologies of systems analysis and simulation to identify, quantify, and interrelate EQIs within a dynamic systems context, provide explicit linkages between causes and effects (vertical integration) and identify cross-linkages among different environmental issues (horizontal integration). 相似文献
968.
969.
创新是企业发展的基础和源泉 总被引:1,自引:0,他引:1
创新是企业的主要功能,是管理现状的客观需要,是企业和员工共同预期的本质要求.树立人本管理思想,提高全员素质,加快信息体系培育,加强组织管理体系建设及价值观和思维方式的更新是创新工作的根源和基础.企业要通过统一认识,加强学习和扎实抓好工作的落实来实现创新工作. 相似文献
970.
The photodegradation of persistent and bioaccumulative perftuorooctanoic acid (PFOA) in water by 185 nm vacuum ultraviolet (VUV) light was examined to develop an effective technology to deal with PFOA pollution. PFOA degraded very slowly under irradiation of 254 nm UV light. However, 61.7% of initial PFOA was degraded by 185 nm VUV light within 2 h, and defluorination ratio reached 17.1%. Pseudo first-order-kinetics well simulated its degradation and defluorination. Besides, fluoride ion formed in water, 4 shorter-chain perfluorinated carboxylic acids (PFCAs), that is, perfluoroheptanoic acid, perfluorohexanoic acid, perfluoropentanoic acid, and perfluorobutanoic acid. These were identified as intermediates by LC-MS measurement. These PFCAs consecutively formed and further degraded with irradiation time. According to the mass balance calculation, no other byproducts were formed. It was proposed that PFCAs initially are decarboxylated by 185 nm light, and the radical thus formed reacts with water to form shorter-chain PFCA with one less CF2 unit. 相似文献