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21.
In a Cd-contaminated environment, not only mature trees but also their seeds and young seedlings can be exposed to Cd. Cadmium taken up by young seedlings may influence mycorrhizal infection, which might in turn influence resistance to Cd toxicity. In order to eliminate soil-mediated responses of mycorrhizal infection to Cd, Pinus sylvestris seedlings were exposed to Cd prior to fungal inoculation and replanted to clean substrates with fungal inoculum. Cadmium pretreatment reduced the proportion of living mycorrhizal short roots of seedlings inoculated with Paxillus involutus. However, no such effect was observed for seedlings inoculated with Suillus bovinus and Rhizopogon subcaerulescens. Therefore, infection by P. involutus appeared to be affected by Cd taken up by seedlings. Overall stem length and biomass of the seedlings were reduced by Cd pretreatment. Infection by S. bovinus and R. subcaerulescens increased stem length and biomass of the seedlings. Root soluble carbohydrate concentrations were lower in mycorrhizal seedlings than non-mycorrhizal seedlings.  相似文献   
22.
The impact of the sulfur (S) content in lubricating oil was evaluated for four ultra-low-emission vehicles and two super-ultra-low-emission vehicles, all with low mileage. The S content in the lube oils ranged from 0.01 to 0.76%, while the S content of the gasoline was fixed at 0.2 ppmw. Vehicles were configured with aged catalysts and tested over the Federal Test Procedure, at idle and at 50-mph cruise conditions. In all testing modes, variations in the S level of the lubricant did not significantly affect the regulated gas-phase tailpipe emissions. In addition to the regulated gas-phase emissions, a key element of the research was measuring the engine-out sulfur dioxide (SO2) in near-real-time. This research used a new methodology based on a differential optical absorption spectrometer (DOAS) to measure SO2 from the lubricants used in this study. With the DOAS, the contribution of SO2 emissions for the highest-S lubricant was found to range from less than 1 to 6 ppm on a gasoline S equivalent basis over the range of vehicles and test cycles used. The development and operation of the DOAS is discussed in this paper.  相似文献   
23.
Jones CG  Wyser K  Ullerstig A  Willén U 《Ambio》2004,33(4-5):211-220
The Rossby Centre regional climate model (RCA2) has been integrated over the Arctic Ocean as part of the international ARCMIP project. Results have been compared to observations derived from the SHEBA data set. The standard RCA2 model overpredicts cloud cover and downwelling longwave radiation, during the Arctic winter. This error was improved by introducing a new cloud parameterization, which significantly improves the annual cycle of cloud cover. Compensating biases between clear sky downwelling longwave radiation and longwave radiation emitted from cloud base were identified. Modifications have been introduced to the model radiation scheme that more accurately treat solar radiation interaction with ice crystals. This leads to a more realistic representation of cloud-solar radiation interaction. The clear sky portion of the model radiation code transmits too much solar radiation through the atmosphere, producing a positive bias at the top of the frequent boundary layer clouds. A realistic treatment of the temporally evolving albedo, of both sea-ice and snow, appears crucial for an accurate simulation of the net surface energy budget. Likewise, inclusion of a prognostic snow-surface temperature seems necessary, to accurately simulate near-surface thermodynamic processes in the Arctic.  相似文献   
24.
The objective of this work was to evaluate absorption and translocation of the herbicide 2,4-D in plants of Memora peregrina. The herbicide 2,4-D was used alone with the formulation DMA 806 BR and associated with the herbicide picloram in the commercial product Padron. Levels of radioactivity on the treated leaves were determined in sample obtained after washing them with methanol and chloroform at different times after the application of the radiolabelled formulation (1, 2, 4, 8, 24, and 48 h). Translocation was evaluated by cutting plants between stem and root. The parts obtained were: root, stem, leaf treated, leaves above the leaf treated, leaves below the leaf treated, and leaf opposite of the leaf treated. These parts were weighted, dried, ground, burnt, and radioactivity in the samples was determined. The results suggest that the translocation of the radioactive herbicide 2,4-D was insignificant in plants of M. peregrina in the two treatments evaluated. Absorption of 14C 2,4-D in the treatment with DMA 806 BR and the mixture of DMA 806 BR plus Padron had the same behavior. These observations explain the inefficient control obtained with this herbicide in plant species under study.  相似文献   
25.
当初,为了ISO14000的通过,花费在做议员的工作、写文件和游说上的时间达数月之久,而今,福特汽车公司所有制造厂的雇员们正致力于实施贯彻ISO14000,同时展开浩大工作的还有其在世界各地各分厂的最高层企业主管们。据环境管理体系经理格雷厄姆·查特本说,福特计划,其全部150个制造厂即使得不到证书,也要从1998年年底开始遵守ISO14000标准。6个厂预计在1996年年底得到证书。全部150个制造厂均处在不同的实施阶段上,他期望至少50家厂将于1997年年底得到证书。查特本正在协调福特公司世界范围内的ISO14000项目,他报告说,“人力的…  相似文献   
26.
This paper addresses environmental monitoring through a robust dynamic integration between biomonitor and biosensor systems, a strategy that has not been attempted before. The two systems are conceptually interrelated and methodologically correlated to a cooperative/synergistic scheme (CSS) with a view to minimise uncertainty and monitoring costs and increase reliability of pollution control and abatement. The structures and operations of the biosensor component (in terms of sensitivity, device and method versatility, nature-mimicking physicochemical mechanisms, prospects and technological input) are such that they reinforce or promote the structures and operations of the natural component (in terms of bio-surveillance, impact assessment, environmental quality indexing, stress responses, metabolic pathways, etc.) and vice versa. The bioindicator ontology presented herein, including concepts, relations and controlled vocabulary aiming at establishing an integrated methodology for mapping/assessing negative environmental externalities, provides a useful tool for the design/development/implementation of an environmental network for the monitoring of a variety of pollutants over time and space and the assessment of environmental quality; the collection of the available information and its classification into taxonomic and partonomic relations allows the construction of a database that links pollutants with organisms' response, at a phenomenological and in-depth level, considering ecological parameters, relations and geomorphologic characteristics. As a result, a computer program has been designed/developed as a decision support system and has been successfully tested on a representative population of species indigenous to southern Greece. Significantly, a novel system in the form of a rational framework at the conceptual design level has been developed, that actually contributes towards achieving a cost-effective long-term monitoring program, with the flexibility to counter on-course any (anticipated or not) variations/modifications of the surveillance environment. This novel and pioneering approach will further offer a dynamic system utilised in (a) environmental impact studies and risk assessment (positive/analytic approach), (b) decision-making in the short-run (normative/tactic approach), and (c) policy-making in the long-run (normative/strategic approach). The proposed CSS, based on the integration of multiple data sources, can establish a local area network, incorporated into/expanding to a wide area network, thus offering the potential of better predictive ability and greater lead-time warning at alarm conditions than that provided by separate, stand-alone surveillance modalities.  相似文献   
27.
A fuzzy decision analysis method for integrating ecological indicators was developed. This was a combination of a fuzzy ranking method and the analytic hierarchy process (AHP). The method was capable of ranking ecosystems in terms of environmental conditions and suggesting cumulative impacts across a large region. Using data on land cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic region, we were able to point out areas that were in relatively poor condition and/or vulnerable to future deterioration. The method offered an easy and comprehensive way to combine the strengths of fuzzy set theory and the AHP for ecological assessment. Furthermore, the suggested method can serve as a building block for the evaluation of environmental policies.  相似文献   
28.
Limitations of multimedia models for use in environmental decision making   总被引:1,自引:0,他引:1  
The United States currently is engaged in a complex,multi-billion dollar effort to cleanup a legacy ofboth privately- and federally-owned hazardous wastesites. Decisions regarding the best approach forremediation of these sites often are based on theanalysis of potential risks to human health and theenvironment. A cornerstone of such analysis is thefrequent use of computerized multimedia environmentaltransport models, to evaluate the large quantities ofinformation necessary to understand the present andfuture implications of contamination at a site. Onebarrier to wide-spread use of this analyticalprocedure is the view that results obtained usingcomputer models are highly dependent on user input,and therefore, subject to manipulation. It is widelyrecognized that for decisions to be both credible andimplementable, the public must have confidence in boththe scientific basis for judgments involved and thedecision processes employed (NRC, 1983). Our purposein this article is to overview the difficultiesassociated with application of multimedia models toreal world problems and the contribution these modelscan make to technically sound estimates of exposure and risk.  相似文献   
29.
This work investigated water samples collected from Tapeng Lagoon and three neighbouring rivers (the Kaoping River, Tungkang River and Lingbeng River) in Taiwan, Republic of China. Canonical discriminant analysis was applied to identify the source of pollution in neighbouring rivers outside Tapeng Lagoon. The two constructed discriminant functions showed a marked contribution to all discriminant variables, and the total nitrogen, algae, dissolved oxygen and total phosphate were combined as the nutrient effect factor. The recognition capacities of the two discriminant functions were 95.6% and 4.4%, respectively. The water quality in the Kaoping River most strongly controlled the water quality in Tapeng Lagoon. Disassembling the oyster frames and fishery boxes had improved the water quality markedly. The methodology and results provide useful information concerning watershed management and may be applicable to other basins with similar properties that are experiencing similar coastal environmental issues.  相似文献   
30.
A simple, rapid and sensitive GC–MS method for the determination of dithiocarbamate fungicide propineb [polymeric zinc propylenebis (dithiocarbamate)] and an improved HPLC procedure for the simultaneous determination of its main metabolite, propylenethiourea, and ethylenethiourea, the main metabolite of all ethylenedithiocarbamates, in airborne samples are described. The method for the analysis of propineb involves the evolution of carbon disulfide (CS2), under acidic conditions in the presence of stannous chloride, extraction of the generated CS2 into a layer of isooctane which is then analyzed for CS2 content by GC–MS in SIM mode. Under the optimum conditions, the retention time of CS2 was 1.89 min and the total time of chromatographic analysis was 5 min. Recoveries from spiking glass microfibre filters (GF/A) and silica gel filters were 86 ± 7 (n = 9) and 89 ± 4 (n = 9), respectively. The limit of detection is 0.7 ng per filter, which is equivalent to about 0.8–1.0 ng m−3 in air. In parallel, an HPLC method with ultraviolet detection is presented for the simultaneous analysis of the metabolites. Separation of the two metabolites was attained in less than 5 min. Recoveries from spiking GF/A and silica gel filters for ethylenethiourea were 100 ± 1 (n = 3) and 98 ± 2 (n = 3), respectively, while for propylenethiourea were 102 ± 1 (n = 3) and 98 ± 1 (n = 3), respectively. The detection limits are about 36–43 and 40–49 ng m−3 in air for ethylenethiourea and propylenethiourea, respectively. All the analytes spiked in the filters are proven to be stable for more than one month, at −4 °C.  相似文献   
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