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果尔对水稻土中厌氧细菌的影响 总被引:2,自引:0,他引:2
探讨了各种浓度的果尔对水稻土中厌氧细菌群的影响,实验表明,低于或等于田间正常施药量的果尔,在1周内对各类氧细菌的生长具有刺激作用,随着施药后时间的延长,刺激作用逐渐消失;高于田间正常施药量的果尔,在1周内对各类厌氧细菌的生长具有明显的抑制作用,随着施药后时间的延长,果尔的降解产物能促进各类厌氧细菌的生长。 相似文献
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Ozone measurements along vertical transects in the Alps 总被引:1,自引:1,他引:0
Herbert Werner Manfred Kirchner Gerhard Welzl Markus Hangartner 《Environmental science and pollution research international》1999,6(2):83-87
To investigate the vertical profiles of air pollutants in the boundary layer, aircraft and balloon-born measurements and measurements
using a cable car as an instrument platform have been performed in different parts of the Alps. This on-line monitoring of
atmospheric pollutants requires expensive and sophisticated techniques. In order to control ambient air quality in remote
regions, where no infrastructure like power supply is available, simple instruments are required. The objective of this study,
which was coordinated and evaluated by the GSF-Forschungszentrum für Umwelt und Gesundheit was first, to investigate the vertical
distribution of ozone in different parts of the Alps and secondly, in addition to continuous analyser measurements, to test
monitoring by means of two types of passive samplers. The selection of these samplers — one for one week use and another one
for two week application — was based on a passive sampler intercomparison done in a preliminary study one year earlier. 相似文献
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The performance of three statistical methods: time-series, multiple linear regression and feedforward artificial neural networks models were compared to predict the daily mean ozone concentrations. The study here reported was based on data from one urban site with traffic influences and one rural background site. The studies were performed for the year 2002 and the respective four trimesters separately. In the multiple linear regression and feedforward artificial neural network models, the concentrations of ozone, the concentrations of its precursors (nitrogen oxides) and some meteorological variables for one and two days before the prediction day were used as predictors. For the application of these models in the validation step, the inputs of ozone concentration for one and two days before were replaced by the ozone concentrations predicted by the models. The results showed that time-series modelling was not profitable. In the development step, similar performances were obtained with multiple linear regression and feedforward artificial neural network. Better performance indexes were achieved with feedforward artificial neural network models in validation step. Concluding, feedforward artificial neural network models were more efficient to predict ozone concentrations. 相似文献
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Synthetic dairy wash-water treatment by using an alternating pumped sequencing batch biofilm reactor
《国际环境与污染杂志》2011,38(4):371-384
The performance of an alternating pumped sequencing batch biofilm reactor process in synthetic diary wash-water treatment was studied. The system comprises two reactors with two identical plastic biofilm modules. Two centrifugal pumps, one connected to each reactor, alternately move the water from one reactor to the other one, resulting in aeration. At three loading rates (336, 501 and 1080 g COD/(m³ d)), total COD and total nitrogen were removed by 91-94% and 46-80%, respectively. Nitrogen was removed from wastewater by denitrification in the anoxic phase and Simultaneous Nitrification and Denitrification (SND) in the aerobic phase. 相似文献
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Cope M Hess D Lee S Tory K Burgers M Lilley B 《Journal of the Air & Waste Management Association (1995)》2008,58(7):858-864
The Australian Air Quality Forecasting System (AAQFS) is one of several newly emerging, high-resolution, numerical air quality forecasting systems. The system is briefly described. A public education application of the air quality impact of motor vehicle usage is explored by computing the concentration and dosage of particulate matter less than 10 microm in aerodynamic diameter (PM10) for a commuter traveling to work between Geelong and Melbourne, Victoria, Australia, under "business-as-usual" and "green" scenarios. This application could be routinely incorporated into systems like AAQFS. Two methodologies for calculating the dosage are described: one for operational use and one for more detailed applications. The Clean Air Research Programme-Personal Exposure Study in Melbourne provides support for this operational methodology. The more detailed methodology is illustrated using a system for predicting concentrations due to near-road emissions of PM10 and applied in Sydney. 相似文献
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Luis E. Sojo Donald S. Gamble Cooper H. Langford Raymond H. Zienius 《Journal of environmental science and health. Part. B》2013,48(6):619-646
Abstract Laurentide humic acid has been titrated with paraquat and with selected divalent metal ions. In some cases, the humic acid was spiked with one cation before titration with another one. Several equivalence points were determined for the binding of the divalent cations, including paraquat. Three equivalence points agreed well with values predicted from the acidic properties of the humic acid. Eight independent experiments gave nine replicate values for an equivalence point that corresponds to 79.2 mole % of the total pairs of carboxyl groups. It is postulated that this represents a large molecular weight or structural fraction of the humic acid. The remaining 20.8 mole % can either bind one divalent cation to two carboxylate anions or bind one divalent cation to one carboxylate anion, with another anion providing for charge balance. Aggregation ‐ disaggregation and dissolution ‐precipitation phenomena may determine which case prevails, and they in turn are sensitive to the chemical compositions of samples. It should be possible to develop analytical chemical methods for characterizing the stoichiometric properties of humic acid samples. 相似文献
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The current approach for modelling ion adsorption onto binary (hydr)oxides using homogeneous surface complexation models involves the assumption of either an ideal mixture of the two surfaces (i.e. two surface sites on one surface) or a patchwise surface (i.e. two surfaces with one surface site on each surface). As the physical truth should be between these two limiting cases, a model which assumes a patchwise surface constituted of three patches is proposed. Two patches represent the distinct (hydr)oxides, and the third one a mixture of these distinct (hydr)oxides. Using the diffuse layer model, the three approaches are applied to literature data for Cd adsorption onto binary mixtures of alumina-coated silica at total constant Cd concentration and varying amounts of alumina coatings. For Cd adsorption onto these binary (hydr)oxide systems, the new approach explains the observed potential effects. The proposed model, which contains two additional adjustable parameters in terms of site concentrations or one adjustable parameter in terms of specific surface area, is more successful than the two limiting cases. The new model is then validated by predicting Ca and Zn behaviour on the same binary (hydr)oxide system. 相似文献
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The mutagenicity of 4 chlorinated phenols, 4 chlorinated catechols, 3 chlorinated guaiacols, one chloromethoxyphenol and one wood preservative mixture was studied in a mammalian cell assay, in which Chinese hamster cells V79 are used. Of the compounds studied 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, 3,4,6-trichlorocatechol, 4,5,6-trichloroguaiacol and the wood preservative were mutagenic in the test system used. 相似文献
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James S. Albert Georgia Destouni Scott M. Duke-Sylvester Anne E. Magurran Thierry Oberdorff Roberto E. Reis Kirk O. Winemiller William J. Ripple 《Ambio》2021,50(1):85
Freshwater ecosystems provide irreplaceable services for both nature and society. The quality and quantity of freshwater affect biogeochemical processes and ecological dynamics that determine biodiversity, ecosystem productivity, and human health and welfare at local, regional and global scales. Freshwater ecosystems and their associated riparian habitats are amongst the most biologically diverse on Earth, and have inestimable economic, health, cultural, scientific and educational values. Yet human impacts to lakes, rivers, streams, wetlands and groundwater are dramatically reducing biodiversity and robbing critical natural resources and services from current and future generations. Freshwater biodiversity is declining rapidly on every continent and in every major river basin on Earth, and this degradation is occurring more rapidly than in terrestrial ecosystems. Currently, about one third of all global freshwater discharges pass through human agricultural, industrial or urban infrastructure. About one fifth of the Earth’s arable land is now already equipped for irrigation, including all the most productive lands, and this proportion is projected to surpass one third by midcentury to feed the rapidly expanding populations of humans and commensal species, especially poultry and ruminant livestock. Less than one fifth of the world’s preindustrial freshwater wetlands remain, and this proportion is projected to decline to under one tenth by midcentury, with imminent threats from water transfer megaprojects in Brazil and India, and coastal wetland drainage megaprojects in China. The Living Planet Index for freshwater vertebrate populations has declined to just one third that of 1970, and is projected to sink below one fifth by midcentury. A linear model of global economic expansion yields the chilling prediction that human utilization of critical freshwater resources will approach one half of the Earth’s total capacity by midcentury. Although the magnitude and growth of the human freshwater footprint are greater than is generally understood by policy makers, the news media, or the general public, slowing and reversing dramatic losses of freshwater species and ecosystems is still possible. We recommend a set of urgent policy actions that promote clean water, conserve watershed services, and restore freshwater ecosystems and their vital services. Effective management of freshwater resources and ecosystems must be ranked amongst humanity’s highest priorities.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01318-8) contains supplementary material, which is available to authorized users. 相似文献
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Klemens JA Wieland ML Flanagin VJ Frick JA Harper RG 《Environmental pollution (Barking, Essex : 1987)》2003,122(2):245-251
Amphibians, turtles, birds (mostly passerines) and mice collected from a conservation area in northwestern Costa Rica were analyzed for organochlorine (OC) pesticide contamination. Six of 39 amphibians (three of eight species), three of six turtles (two species), one of eight mice (one species) and 19 of 55 birds (five of seven species) contained OCs at levels up to 580 ng/g. The most frequently detected compound in 23 of 108 organisms was p,p'DDE. Dieldrin, delta-BHC, heptachlor, p,p'DDD, and endosulfan II were each found in at least four organisms, while eight other OCs were found in at least one organism. The presence of OCs in taxa from the conservation area indicates the likelihood of long-distance transport of such compounds through the atmosphere. 相似文献
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《国际环境与污染杂志》2011,32(3):387-409
This paper aims to evaluate the impact of a polluted site on property values by using the hedonic price method. The case study concerns a lead foundry in a previously industrialised area in northern France. The results are fairly convincing. The impact is confirmed, but appears to be especially apparent at relatively close distances. More than one mile away, the impact is much weaker. Moreover, a chronological analysis, which includes interaction terms, allows one to demonstrate a significant variability in results, depending upon the years being examined. The results obtained are compared with those derived from US studies. It appears that more than one mile away, the calculated impact values are fairly similar, about 1–2% of the average value of a house. In contrast, bearing in mind the higher average property values in the USA, gradient prices in absolute values are, in general, higher in that country. 相似文献
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厌氧菌降解四氯乙烯的研究 总被引:2,自引:0,他引:2
报道了洳气污泥富集培养物中厌氧菌降解四氯乙烯的特征。研究结果表明,沼气污泥在甲醇、甲酸盐、乙酸盐、乙醇和H2/CO2等不同碳源基质中的富集培养物,以利用甲醇为碳源的富信培养物降解四氯乙烯(Tetrachloroe-thylene,简称PCE,下同)活性最高,平均每升培养液每天降解PCE1400nmol。经对该富集培养物的分离培养,已分离出4株厌氧细菌,其中一株为甲烷八叠球菌,两株为弧菌,一株为杆菌 相似文献
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Scale-dependence of land use effects on water quality of streams in agricultural catchments 总被引:4,自引:0,他引:4
The influence of land use on water quality in streams is scale-dependent and varies in time and space. In this study, land cover patterns and stocking rates were used as measures of agricultural development in two pasture and one native grassland catchment in New Zealand and were related to water quality in streams of various orders. The amount of pasture per subcatchment correlated well to total nitrogen and nitrate in one catchment and turbidity and total phosphorous in the other catchment. Stocking rates were only correlated to total phosphorous in one pasture catchment but showed stronger correlations to ammonium, total phosphorous and total nitrogen in the other pasture catchment. Winter and spring floods were significant sources of nutrients and faecal coliforms from one of the pasture catchments into a wetland complex. Nutrient and faecal coliform concentrations were better predicted by pastural land cover in fourth-order than in second-order streams. This suggests that upstream land use is more influential in larger streams, while local land use and other factors may be more important in smaller streams. These temporal and spatial scale effects indicate that water-monitoring schemes need to be scale-sensitive. 相似文献
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Milk and milk products have shown to be good indicator samples for the contamination of persistent organic pollutants (POPs) along the food chain. To gather information on whether exposure to dioxins and PCBs might cause a problem in countries about to join the European Union in 2004 or later, a study for evaluation of dioxin and levels of PCBs in 16 butter samples from eight countries (Cyprus, Czech Republic, Estonia, Lithuania, Poland, Romania, Slovenia and Slovakia) was performed. Comprehensive quality assurance/quality control (QA/QC) was requested. For this, eight quality control samples were included (in comparison to long-term mean, mean recovery for WHO-PCDD/F-TEQ of 97.9% with a CV of 3.0%, mean recovery for WHO-PCB-TEQ of 100.4% with a CV of 3.3%). Additionally, all butter samples were run as duplicates resulting in a confidence region of 95% statistical certainty of 4.6% for WHO-PCDD/F-TEQ and of 3.5% for WHO-PCB-TEQ. All samples except one from Romania were in the range of 0.21-0.59 pg WHO-PCDD/F-TEQ/g fat (upper bound), all samples except one from Romania and one from Estonia in the range of 0.32-0.82 pg WHO-PCB-TEQ/g fat (upper bound) and all samples except one from Romania and one from Estonia in the range of 0.57-1.23 pg sum WHO-TEQ/g fat (upper bound). The maximum values were found in samples from Romania (0.98 pg WHO-PCDD/F-TEQ/g fat; 1.75 pg WHO-PCB-TEQ/g fat) and Estonia (0.26 pg WHO-PCDD/F-TEQ/g fat; 1.62 pg WHO-PCB-TEQ/g fat). As a conclusion, all samples except one from Romania and one from Estonia were in the range of the actual low background contamination for PCDD/F and dioxin-like PCBs. The samples with elevated concentrations were below the EU action and maximum levels which have been valid since 2002, or will be applied from November 2006. In all samples except in one from Estonia, the contribution of dioxin-like PCBs to sum WHO-TEQ was 47-68% which reflects the usual range in Europe. In one sample from Estonia this contribution was 86% which points to a particular yet unknown PCB source. Thirty eight PCB congeners were determined allowing a detailed discussion of the relative contribution of individual congeners to the total PCB concentration. Correlation between PCB 153 and WHO-PCB-TEQ varied considerably between samples from different countries. Major tetra- or pentachlorinated mono-ortho PCBs without assigned TEFs were PCBs 60, 66, 74, and 110. 相似文献
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《Atmospheric environment (Oxford, England : 1994)》2001,35(35):6181-6191
The atmospheric oxidation of several terpenes appears to be a potentially relevant source of acetone in the atmosphere. Proton-transfer-reaction mass spectrometry was used as an on-line analytical method in a chamber study to measure acetone and other gas phase products from the oxidation of α- and β-pinene initiated by OH radicals in air and in the presence of NOx.Acetone may be formed promptly, following attack by the OH radical on the terpene, via a series of highly unstable radical intermediates. It can also be formed by slower processes, via degradation of stable non-radical intermediates such as pinonaldehyde and nopinone.Primary acetone and pinonaldehyde molar yields of 11±2% (one σ) and 34±9% (one σ), respectively, were found from the reaction between α-pinene and the OH radical. After all α-pinene had been consumed, an additional formation of acetone due to the degradation of stable non-radical intermediates was observed. The total amount of acetone formed was 15±2% (one σ) of the reacted α-pinene. An upper limit of 12±3% (one σ) for the acetone molar yield from the oxidation of pinonaldehyde was established.From the reaction between β-pinene and the OH radicals, primary acetone and nopinone molar yields of 13±2% (one σ) and 25±3% (one σ), respectively, were observed. Additional amounts of acetone were formed by the further degradation of the primary product, such as the most abundant product nopinone. The total amount of acetone formed was 16±2% (one σ) of the reacted β-pinene. An upper limit of 12±2% (one σ) for the acetone molar yield from the oxidation of nopinone was established.The observed product yields from α- and β-pinene are in good agreement with other studies using mass-spectrometric and gas chromatographic analytical techniques, but differ significantly from previous studies using spectroscopic methods. Possible reasons for the discrepancies are discussed. 相似文献