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511.
Ozone treatment of soil contaminated with aniline and trifluralin   总被引:1,自引:0,他引:1  
Column studies were conducted to determine the ability of ozone to degrade aniline and trifluralin in soil. Ozone rapidly degraded aniline from soil under moist soil conditions, 5% (wt). Removal of 77-98% of [UL-14C]-aniline was observed from soil columns (15 ml, i.d. = 2.5 cm), exposed to 0.6% O(3) (wt) at 200 ml/min after 4 min. Initial ozonation products included nitrosobenzene and nitrobenzene, while further oxidation led to CO(2). Ring-labeled-[UL-14C]-trifluralin removal rates were slower, requiring 30 min to achieve removals of 70-97%. Oxidation and cleavage of the N-propyl groups of trifluralin was observed, affording 2,6-dinitro-4-(trifluoromethyl)-aniline, 2,6-dinitro-N-propyl-4-(trifluoromethyl)-benzamine, and 2,6-dinitro-N-propyl-N-acetonyl-4-(trifluoromethyl)-benzamine. Base solutions revealed that trifluralin was similarly oxidized to CO(2), where 72-83% of the activity recovered comprised 14CO(2). Use of ozone-rich water improved contaminant removal in trifluralin-amended soil columns, but did not improve removal in aniline, pentachloroaniline, hexachlorobenzene amended soil columns, suggesting that ozonated water may improve contaminant removal for reactive contaminants of low solubility.  相似文献   
512.
The question addressed by this study is how a large urban water district can best respond to a drought. Using a computer model of a representative district, we find that a combination of conjunctive use and water marketing is well over an order of magnitude cheaper than the traditional alternative of constructing new storage capacity. The indicated cost saving can be explained by the intermittent nature of the transfer, corresponding to the intermittent demand. Comparing costs to benefits, the consumer-surplus loss otherwise entailed by raising prices to cut back on consumption in the event of a drought, we find that construction of new storage does not pass a benefit/cost test, but introduction of conjunctive use/water marketing does.  相似文献   
513.
It is an established fact that property owners can face significant liabilities as a result of an on-site environmental contamination problem. This paper outlines a successful, innovative remedial strategy that, in conjunction with agency negotiation, afforded a property owner minimal financial expenditure and, at the same time, facilitated property cleanup and reuse. The strategy includes the delisting and sale of “clean” portions of the property to obtain the finances necessary to remediate the remaining “impacted” portion of the property. Previous investigations performed by EPA indicate the affected area to be a five to seven acre area located in the northeast portion of the property. Since a portion of the property was affected, significant restrictions for long-term use were placed on the entire property. A summary of environmental data generated for the property was prepared and submitted to the agency. This data summary communicated a strategy which was developed to delist and sell the “clean” portion of the property and to use the proceeds to clean up the affected property. To accomplish this, several tasks were outlined, including work-plan preparation and submittal, data collection, and interim remedial activities. In addition, a risk assessment is planned to identify potential threats to receptors downgradient of the impacted areas. This strategy allows the owner of an environmentally distressed property to use financial assets of the property to facilitate an acceptable solution with both regulatory agencies and the surrounding community.  相似文献   
514.
The addition of synthetic zeolites and similar materials to metal contaminated soils has been shown to reduce soil phytotoxicity and to improve the quality of plant growth on such amended soils. To gain an understanding of the mechanism by which the phytotoxicity of contaminated soils is reduced when treated with synthetic zeolites, sequential extraction procedures and soil solution techniques have been used to identify changes associated with metal speciation in amended soils. Sequential extraction data and changes in soil solution composition are presented for three different contaminated soils, amended with three synthetic zeolites (P, 4A and Y) at concentrations of 0.5%, 1% and 5% w/w, or lime at 1%. The soils were collected from the site of a metal refinery, an old lead zinc mine spoil tip and from a field which had been treated with sewage sludge. After incubation of the zeolite treated soils for between one and three months, results showed a reduction in the metal content of the ammonium acetate fraction between 42% and 70%, depending on soil, zeolite and rate of addition, compared with the unamended soils. In addition, soil solution experiments indicated that synthetic zeolite amendments were more efficient at reducing metal content than comparable lime treatment. The mechanism by which synthetic zeolites reduce metal bioavailability in contaminated soils is discussed and compared to other amendments.  相似文献   
515.
The face is an important visual trait in social communication across many species. In evolutionary terms, there are large and obvious selective advantages in detecting healthy partners, both in terms of avoiding individuals with poor health to minimise contagion and in mating with individuals with high health to help ensure healthy offspring. Many models of sexual selection suggest that an individual's phenotype provides cues to their quality. Fluctuating asymmetry is a trait that is proposed to be an honest indicator of quality, and previous studies have demonstrated that rhesus monkeys gaze longer at symmetric faces, suggesting preferences for such faces. The current study examined the relationship between measured facial symmetry and measures of health in a captive population of female rhesus macaque monkeys. We measured asymmetry from landmarks marked on front-on facial photographs and computed measures of health based on veterinary health and condition ratings, number of minor and major wounds sustained and gain in weight over the first 4?years of life. Analysis revealed that facial asymmetry was negatively related to condition-related health measures, with symmetric individuals being healthier than more asymmetric individuals. Facial asymmetry appears to be an honest indicator of health in rhesus macaques, and asymmetry may then be used by conspecifics in mate-choice situations. More broadly, our data support the notion that faces are valuable sources of information in non-human primates and that sexual selection based on facial information is potentially important across the primate lineage.  相似文献   
516.
Second trimester biomarkers were initially introduced with the intent of screening for neural tube defects and then subsequently for Down syndrome. It was soon realized that these markers can be indirect evidence of abnormal placentation and, therefore, can be used for screening for adverse pregnancy outcomes. Several new biomarkers have subsequently been described with conflicting findings regarding their efficiency for screening for adverse pregnancy outcomes. Although a biologically feasible mechanism has been proposed for the role of these biomarkers, they still fall short of an ideal screening test to be clinically useful. © 2014 John Wiley & Sons, Ltd.  相似文献   
517.
518.
This paper introduces a new argument to the debate about the role of environmental taxes in modern tax systems. Some environmental taxes, particularly taxes on gasoline or electricity, are more difficult to evade than taxes on labor or income. When the tax base is shifted in a revenue-neutral manner toward these environmental taxes, the result is a net reduction in the amount of tax evasion. Using a carbon tax as a motivating example, the “tax evasion effect” is shown to sharply reduce the welfare cost of controlling emissions. A simple computable general equilibrium model suggests that the impact of considering tax evasion can be large: costs are lowered by 28% in the United States, by 89% in China, and by 97% in India. In countries with high levels of pre-existing tax evasion, a carbon tax will pay for itself through improvements in the efficiency of the tax system.  相似文献   
519.
520.
The levels of BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209 were determined in the dust sampled from 60 automobiles that were available for resale at U.S. dealerships. The dominant congener in automobile dust was BDE-209 comprising 95% of the total PBDE levels with a median level of 48.1 µg g? 1. Statistical analysis of the vehicle attributes indicates that the BDE-209 levels are different (p < 0.05) with respect to groupings by vehicle model year, vehicle manufacturer, and the country of manufacture. Vehicle dust samples contained the characteristic profile of the PBDE congeners that comprise the PentaBDE formulation. While DecaBDE use is banned in Maine and Washington and is targeted for restriction in the near future by six U.S. states, vehicles and airplanes are exempt from the ban. It is anticipated that the human exposure potential to PBDEs from automobile dust ingestion will continue for an indefinite future period in the U.S. population.  相似文献   
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