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41.
42.
Ariamalar Selvakumar Mary Ellen Tuccillo Swarna Muthukrishnan Asim B. Ray 《补救:环境净化治理成本、技术与工艺杂志》2009,19(2):135-142
Several compositions of Fenton's Reagent and hydrogen peroxide alone were used to disinfect combined sewage samples from a wastewater treatment facility. The presettled samples contained suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L, respectively. Disinfection with Fenton's Reagent was carried out at a pH between 5.90 and 6.0 and at a temperature of 25°C. All disinfected samples contained residual oxidants. Under all reaction conditions studied, complete inactivation of E. coli was achieved within one minute of the addition of Fenton's Reagent. Disinfection with hydrogen peroxide alone under similar conditions is incomplete even under much longer contact times. © 2009 Wiley Periodicals, Inc. 相似文献
43.
Gerald Kirchner Friederike Strebl Peter Bossew Sabine Ehlken Martin H. Gerzabek 《Journal of environmental radioactivity》2009
Literature data on numerical values obtained for the parameters of the two most popular models for simulating the migration of radionuclides in undisturbed soils have been compiled and evaluated statistically. Due to restrictions on the applicability of compartmental models, the convection–dispersion equation and its parameter values should be preferred. For radiocaesium, recommended values are derived for its effective convection velocity and dispersion coefficient. Data deficiencies still exist for radionuclides other than caesium and for soils of non-temperate environments. 相似文献
44.
Shui-Yan Tang Carlos Wing-Hung Lo Gerald E. Fryxell 《Journal of environmental management》2010,91(10):2008-2018
This paper examines how configurations of external support factors have evolved alongside governance reform in recent years and how these evolving configurations have affected regulatory enforcement in four counties in Guangdong Province in China. Based on in-depth interviews with leading officials in the local environmental protection bureaus (EPBs), we show that there have been increases in government and societal support for local EPBs in their regulatory work, thanks partly to a number of recent governance reform efforts, but many problems have remained. Based on a questionnaire survey of enforcement officials, we examine how the perceptions of government and societal support are related to EPB officials’ self-perception of effectiveness. It is found that both local government support and societal support have an influence on enforcement officials’ self-assessment of effectiveness, but the relationships varied considerably depending on various dimensions of effectiveness and the patterns of interactions between government and societal support. 相似文献
45.
Patrick Riefer Timm Klausmeyer Andreas SchäFfer Jan Schwarzbauer Burkhard Schmidt 《Journal of environmental science and health. Part. B》2013,48(5):394-403
Anthropogenic contaminants like nonylphenols (NP) are added to soil, for instance if sewage-sludge is used as fertilizer in agriculture. A commercial mixture of NP consists of more than 20 isomers. For our study, we used one of the predominate isomers of NP mixtures, 4-(3,5-dimethylhept-3-yl)phenol, as a representative compound. The aim was to investigate the fate and distribution of the isomer within soil and soil derived organo-clay complexes. Therefore, 14C- and 13C-labeled NP was added to soil samples and incubated up to 180 days. Mineralization was measured and soil samples were fractionated into sand, silt and clay; the clay fraction was further separated in humic acids, fulvic acids and humin. The organo-clay complexes pre-incubated for 90 or 180 days were re-incubated with fresh soil for 180 days, to study the potential of re-mobilization of incorporated residues. The predominate incorporation sites of the nonylphenol isomer in soil were the organo-clay complexes. After 180 days of incubation, 22 % of the applied 14C was mineralized. The bioavailable, water extractable portion was low (9 % of applied 14C) and remained constant during the entire incubation period, which could be explained by an incorporation/release equilibrium. Separation of organo-clay complexes, after extraction with solvents to release weakly incorporated, bioaccessible portions, showed that non-extractable residues (NER) were preferentially located in the humic acid fraction, which was regarded as an effect of the chemical composition of this fraction. Generally, 27 % of applied 14C was incorporated into organo-clay complexes as NER, whereas 9 % of applied 14C was bioaccessible after 180 days of incubation. The re-mobilization experiments showed on the one hand, a decrease of the bioavailability of the nonylphenol residues due to stronger incorporation, when the pre-incubation period was increased from 90 to 180 days. On the other hand, a shift of these residues from the clay fraction to other soil fractions was observed, implying a dynamic behavior of incorporated residues, which may result in bioaccessibility of the NER of nonylphenol. 相似文献
46.
47.
Lifjeld JT Kleven O Jacobsen F McGraw KJ Safran RJ Robertson RJ 《Behavioral ecology and sociobiology》2011,65(9):1687-1697
When males become more ornamented and reproduce more successfully as they grow older, phenotypic correlations between ornament
exaggeration and reproductive success can be confounded with age effects in cross-sectional studies, and thus say relatively
little about sexual selection on these traits. This is exemplified here in a correlative study of male fertilization success
in a large colony of American barn swallows (Hirundo rustica erythrogaster). Previous studies of this species have indicated that two sexually dimorphic traits, tail length and ventral plumage coloration,
are positively correlated with male fertilization success, and a mechanism of sexual selection by female choice has been invoked.
However, these studies did not control for potential age-related variation in trait expression. Here, we show that male fertilization
success was positively correlated with male tail length but not with plumage coloration. We also show that 1-year-old males
had shorter tails and lower fertilization success than older males. This age effect accounted for much of the covariance between
tail length and fertilization success. Still, there was a positive relationship between tail length and fertilization success
among older males. But as this group consisted of males from different age classes, an age effect may be hidden in this relationship
as well. Our data also revealed a longitudinal increase in both tail length and fertilization success for individual males.
We argue that age-dependent ornament expression and reproductive performance in males complicate inferences about female preferences
and sexual selection. 相似文献
48.
Claudia S. Hak Mattias Hallquist Evert Ljungström Maria Svane Jan B.C. Pettersson 《Atmospheric environment (Oxford, England : 1994)》2009,43(15):2481-2488
A method for continuous on-road measurements of particle number emissions for both diesel- and petrol-fuelled vehicles is presented. The setup allows the determination of particle number emission factors on an individual vehicle basis by the simultaneous measurement of CO2 and particle concentrations. As an alternative to previous measurements on the kerbside, the sample is taken directly in the street, with the advantage of sampling in-situ within the exhaust plumes of passing vehicles, allowing the separation of the individual high-concentration plumes. The method was tested in two experiments that were conducted in the Gothenburg area. In the first study, which was performed at an urban roadside, we were able to determine particle emission factors from individual vehicles in a common car fleet passing the measurement site. The obtained emission factors were of the same order of magnitude (between 1.4 × 1012 and 1.8 × 1014 particles km?1) as values published in the recent literature for light duty vehicles. An additional on-road experiment was conducted at a rural road with four light duty reference vehicles (three of them petrol-powered and one diesel-powered) at driving speeds of 50 and 70 km h?1, realised with different engine speeds. The results of the traffic emission studies show that the method is applicable provided that instruments with an adequate dynamic range are used and that the traffic is not too dense. In addition, the variability in particle emissions for a specified driving condition was estimated. 相似文献
49.
Regina Lindborg Marie Stenseke Sara A.O. Cousins Jan Bengtsson Åke Berg Tomas Gustafsson N. Erik Sjödin Ove Eriksson 《Journal of environmental management》2009,90(2):499-508
Agriculture is the major land use at a global scale. In addition to food production, multifunctionality of landscapes, including values and ecosystem services like biodiversity, recreation and culture, is now focus for management. This study explores how a scenario approach, involving different stakeholders, may help to improve landscape management for biodiversity conservation. Local farmers and executives at the County Administrative Board were invited to discuss rural development and conditions for farmland biodiversity in two Swedish landscapes. The potential biodiversity for three future land use scenarios for the two landscapes was discussed: nature conservation, outdoor recreation and energy production, and compared with current and historical landscapes in each region.Analyses of habitat areas, connectedness and landscape diversity suggested that the energy and recreation scenarios had a negative impact on farmland biodiversity, whereas the nature conservation scenario, the current and historically reconstructed landscapes had a higher potential for biodiversity. The farmers appreciated the nature conservation scenario, but also the energy production scenario and they highlighted the need of increased subsidies for management of biodiversity. The farmers in the high production area were less interested in nature quality per se. The executives had similar opinions as the farmers, but disagreed on the advantages with energy production, as this would be in conflict with the high biodiversity and recreational values. The local physical and socio-economical conditions differ between landscapes and potentially shaped the stakeholders emotional attachment to the local environment, their opinions and decisions on how to manage the land. We stress the importance of incorporating local knowledge, visions and regional prerequisites for different land uses in conservation, since site and landscape specific planning for biodiversity together with a flexible subsidy system are necessary to reach the conservation goals within EU. 相似文献
50.
In 1988 the Toronto World Conference on the Changing Atmosphere called for a reduction of CO2 emissions of the industrialized countries by approximately 20% by the year 2005 as compared with 1988. A stabilization of
CO2 concentrations would require an eventual emissions reduction of more than 50% of present levels. Model runs were performed
with the Dutch Integrated Model for the Assessment of the Greenhouse Effect (IMAGE) to put these figures into perspective.
It was found that the suggested emissions reduction levels could indeed be adequate to prevent global temperature change from
moving beyond past climate experience. However, this would only be the case when these reduced levels of emissions were achieved
at a global scale and maximum emission control for the other greenhouse gases was implemented. A delayed response analysis
shows that the policies of the coming decades are crucial for the eventual control of the greenhouse effect. 相似文献