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471.
Unconventional oil and gas extraction (UOGE) has spurred an unprecedented boom in onshore production in the US. Despite a surge in related research, a void exists regarding inquiries into policy outcomes and perceptions. To address this, support for federal regulatory exemptions for UOGE is examined using survey data collected in 2015 from two Northern Colorado communities. Current regulatory exemptions for UOGE can be understood as components of broader societal processes of neoliberalization. Free market ideology increases public support for federal regulatory exemptions for UOGE. Perceived negative impacts do not necessarily drive people to support increased federal regulation. Utilizing neo-Polanyian theory, interaction between free market ideology and perceived negative impacts is explored. Free market ideology appears to moderate people’s views of regulation: increasing the effect of perceived negative impacts while simultaneously increasing support for deregulation. To conclude, the ways in which free market ideology might normalize the impacts of UOGE activity are discussed.  相似文献   
472.
Determining the carbon-to-chlorophyll ratio of natural phytoplankton   总被引:6,自引:0,他引:6  
K. Banse 《Marine Biology》1977,41(3):199-212
For field samples, regression analyses of plots of chemically determined particulate organic carbon on chlorophyll are often employed to estimate the algal carbon-to-chlorophyll ratio (F) in the presence of appreciable amounts of nonalgal particulate organic carbon. Spurious results will be obtained, however, if the temporal rate of change of the algae or the nonplant matter reverses its sign during the sampling interval and the samples cannot be ordered correctly in time or space. Previously recognized sources of bias inherent in the chemical approach are also discussed. The great uncertainty of our present knowledge of F is pointed out. It is shown that the concentration of microscopically visible, nonliving particles in the sea isnot known. Renewed studies are suggested as a means of improving on the chemical approach to determining F. The general argument holds for the ratios of nitrogen (particle volume, etc.)-to-chlorophyll, carbon (nitrogen, particle volume, etc.)-to-ATP, and similar conversion factors.Contribution No. 932 from the Department of Oceanography, University of Washington, Seattle, Washington 98195, USA. The article is a revised and expanded version of a paper contributed at the Joint Oceanographic Assembly, September 1976, at Edinburgh, Scotland, UK.  相似文献   
473.
Environmental Science and Pollution Research - Microplastics are considered to be ubiquitous and widespread emerging contaminants. They are persistent in the nature and pose considerable harm to...  相似文献   
474.
475.
Field studies of chemical changes in surface waters associated with rainfall and snowmelt events have provided evidence of episodic acidification of lakes and streams in Europe and North America. Modelling these chemical changes is particularly challenging because of the variability associated with hydrological transport and chemical transformation processes in catchments. This paper provides a review of mathematical models that have been applied to the problem of episodic acidification. Several empirical approaches, including regression models, mixing models and time series models, support a strong hydrological interpretation of episodic acidification. Regional application of several models has suggested that acidic episodes (in which the acid neutralizing capacity becomes negative) are relatively common in surface waters in several regions of the US that receive acid deposition. Results from physically based models have suggested a lack of understanding of hydrological flowpaths, hydraulic residence times and biogeochemical reactions, particularly those involving aluminum. The ability to better predict episodic chemical responses of surface waters is thus dependent upon elucidation of these and other physical and chemical processes.  相似文献   
476.
It has been observed that as soil-pollutant contact time increases, pollutant bioavailability and extractability decreases. This phenomenon has been termed 'ageing'. Decreased chemical extractability with increased soil-chemical contact time is evident where both 'harsh' techniques, e.g. dichloromethane Soxhlet extraction, and 'non-exhaustive' techniques, e.g. butanol shake extraction, have been used. It has also been observed that the amount of chemical extracted by these techniques varies considerably over time. Similarly, decreases in bioavailability with increased soil-pollutant contact time have been described in bacterial, earthworm and other organism studies. From these investigations, it has been shown that the fraction of pollutant determined to be bioavailable can vary between organisms. Thus, there is an immediate definition problem, what is bioavailability? Additionally, if bioavailability is to be assessed by a chemical means, which organisms should (or can) be mimicked by the extraction procedure? This review provides a background to the processes inherent to ageing, a discussion of its consequences on bioavailability and ends with some reflections on the appropriateness of chemical extraction techniques to mimic bioavailability  相似文献   
477.
A rapid protocol was developed to measure 10 different enzymic activities from a large number of 1-cm-sliced freshly collected lake sediments. Layers heavily polluted by organic halogens (4900 mg Cl kg(-1)) revealed severe depression of phosphatase, sulfatase, leucine-aminopeptidase, chitinase, acetate esterase and butyrate esterase activities as compared to layers above and below the most polluted zone. alpha-Glucosidase, beta-glucosidase, beta-xylosidase and palmitate esterase were less affected. Methane oxidation potential was dramatically depressed in the polluted strata whereas tetrachloromethane dehalogenating activity was observed in the polluted sediment only. The sediment layers formed after the chlorine discharges into the lake had diminished to 1/10, and showed restoration of the activities close to those observed in non-recipient sediment, in spite of the persisting presence of >1000 mg of organic chlorine (kg dry wt)(-1). We conclude that certain enzymic activities involved in breakdown or oxidation of organic matter in the sediments are useful probes for assessing the degree of ecological damage and its potential for restoration in recipient lakes of industrial discharges.  相似文献   
478.
PCDD/F reduction in incinerator flue gas by adding urea to RDF feedstock   总被引:2,自引:0,他引:2  
The effect of urea on PCDD/F formation in a pilot incinerator was studied by incinerating urea with refuse-derived fuel (RDF) at three concentrations (0.1%, 0.5% and 1.0%, of the fuel feed). A distinct reduction in both PCDD/F and chlorophenol concentrations could be noticed when urea was introduced into the system. Partial-least-square (PLS) analysis of the data showed the importance of certain chlorophenol isomers as PCDD/F precursors, pointing to the possibility that the impact point of the urea inhibitor could be before the precursor molecules, i.e. chlorophenols, have been formed.  相似文献   
479.
480.
Endosulfan (1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-en-2,3-ylenedimethylsulphite) and quinalphos (O,O-diethyl O-quinoxalin-2-yl phosphorothioate) persistence and their effect on soil microarthropods were studied after repeated applications in cotton fields. Dissipation behavior of insecticides after repeated applications was observed from 78 to 292 days after the first insecticide treatment. At any given time the concentrations of endosulfan beta residues were always higher as compared to endosulfan alpha. From 78 to 85 days, 5.0% and 20.4% decrease in alpha and beta endosulfan residues was observed, respectively. Endosulfan beta isomer decreased up to 93.0% in 292 days. Endosulfan sulfate was detected as a major metabolite in the soil samples. Total endosulfan residues decreased by 86.6% from 78 to 292 days. The amounts of quinalphos residues were less as compared to endosulfan at any given time. The residues observed after 78 days of application were 0.88 ng g-1 d wt. soil. At the end of 145 days, a 35.0% decrease in quinalphos residue was observed, which decreased further by 50.9% in 292 days. Among the soil microarthropods studied, Acarina was more sensitive to the applied insecticides as compared to Collembola. Three days after the last treatment, up to 94.5% (p < 0.01) and 71.2% (p < 0.05) decrease in Acarina population was observed in endosulfan and quinalphos treated fields, respectively, compared to control field. In general, no noticeable change in Collembola population was observed after the insecticide treatments.  相似文献   
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