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711.
Forest road decommissioning is a pro-active mechanism for preventing future habitat degradation and for increasing the likelihood
of endangered salmonid survival in the western U.S. High implementation costs however preclude many desirable projects from
being undertaken, especially on federally owned land. Previous research and real-world applications have demonstrated the
cost savings potential of reusing aggregate recovered from forest roads during decommissioning. These cost savings can effectively
subsidize decommissioning projects, suggesting an economic benefit associated with improving environmental benefit. We present
a mixed integer, multiple objective formulation to identify the efficient trade-off surface between conflicting economic and
environmental criteria, where environmental benefit is defined as the hazard weighted length of roads decommissioned. We compare
nondominated frontiers identified with and without the opportunity to recycle aggregate. Our results suggest that aggregate
recycling promotes a synergistic relationship between cost savings (subsidy) and environmental performance, where subsidies
generally increase with increasing environmental performance. Effective subsidy values can reach 31% of total expenditure,
at the maximum level of environmental benefit. Transportation managers are therefore able to recover and reuse a nonrenewable
resource, while at the same time promoting economic and environmental efficiency. 相似文献
712.
A field study was conducted on a Lowell silty loam soil of 2.7% organic matter at the Kentucky State University Research Farm, Franklin County, Kentucky. Eighteen universal soil loss equation (USLE) standard plots (22 x 3.7 m each) were established on a 10% slope. Three soil management practices were used: (i) class-A biosolids (sewage sludge), (ii) yard waste compost, each mixed with native soil at a rate of 50 ton acre(-1) on a dry-weight basis, and (iii) a no-mulch (NM) treatment (rototilled bare soil), used for comparison purposes. Devrinol 50-DF "napropamide" [N,N-diethyl-2-(1-naphthyloxy) propionamide] was applied as a preemergent herbicide, incorporated into the soil surface, and the plots were planted with 60-day-old sweet bell pepper seedlings. Napropamide residues one hour following spraying averaged 0.8, 0.4, and 0.3 microg g(-1) dry soil in sewage sludge, yard waste compost, and no-mulch treatments, respectively. Surface runoff water, runoff sediment, and napropamide residues in runoff were significantly reduced by the compost and biosolid treatments. Yard waste compost treatments increased water infiltration and napropamide residues in the vadose zone compared to sewage sludge and NM treatments. Total pepper yields from yard waste compost amended soils (9187 lbs acre(-1)) was significantly higher (P < 0.05) than yield from either the soil amended with class-A biosolids (6984 lbs acre(-1)) or the no-mulch soil (7162 lbs acre(-1)). 相似文献
713.
Evaluation of alternative landfill cover soils for attenuating hydrogen sulfide from construction and demolition (C&D) debris landfills 总被引:1,自引:0,他引:1
Hydrogen sulfide (H(2)S) generated from C&D debris landfills has emerged as a major environmental concern due to odor problems and possible health impacts to landfill employees and surrounding residents. Research was performed to evaluate the performance of various cover materials as control measures for H(2)S emissions from C&D debris landfills. Twelve laboratory-scale simulated landfill columns containing gypsum drywall were operated under anaerobic conditions to promote H(2)S production. Five different cover materials were placed on top of the waste inside duplicate columns: (1) sandy soil, (2) sandy soil amended with lime, (3) clayey soil, (4) fine concrete (particle size less than 2.5 cm), and (5) coarse concrete (particle size greater than 2.5 cm). No cover was placed on two of the columns, which were used as controls. H(2)S concentrations measured from the middle of the waste layer ranged from 50,000 to 150,000 ppm. The different cover materials demonstrated varying H(2)S removal efficiencies. The sandy soil amended with lime and the fine concrete were the most effective for the control of H(2)S emissions. Both materials exhibited reduction efficiencies greater than 99%. The clayey and sandy soils exhibited lower reduction efficiencies, with average removal efficiencies of 65% and 30%, respectively. The coarse concrete was found to be the least efficient material as a result of its large particle size. 相似文献
714.
Matthew F. Child S. A. Jeanetta Selier Frans G. T. Radloff W. Andrew Taylor Michael Hoffmann Lizanne Nel R. John Power Coral Birss Nicola C. Okes Michael J. Peel David Mallon Harriet Davies-Mostert 《Conservation biology》2019,33(5):1106-1119
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species. 相似文献
715.
Juhasz AL Smith E Weber J Rees M Rofe A Kuchel T Sansom L Naidu R 《Chemosphere》2008,71(10):1963-1969
Considerable information is available in the literature regarding the uptake of arsenic (As) from contaminated soil and irrigation water by vegetables. However, few studies have investigated As speciation in these crops while a dearth of information is available on As bioavailability following their consumption. In this study, the concentration and speciation of As in chard, radish, lettuce and mung beans was determined following hydroponic growth of the vegetables using As-contaminated water. In addition, As bioavailability was assessed using an in vivo swine feeding assay. While As concentrations ranged from 3.0 to 84.2mg As kg(-1) (dry weight), only inorganic As (arsenite and arsenate) was detected in the edible portions of the vegetables. When As bioavailability was assessed through monitoring blood plasma As concentrations following swine consumption of As-contaminated vegetables, between 50% and 100% of the administered As dose was absorbed and entered systemic circulation. Arsenic bioavailability decreased in the order mung beans>radish>lettuce=chard. 相似文献
716.
Matthew S. MacLennan Cai Tie Kevin Kovalchik Kerry M. Peru Xinxiang Zhang John V. Headley David D.Y. Chen 《环境科学学报(英文版)》2016,28(11):203-212
Capillary electrophoresis coupled to mass spectrometry(CE–MS) was used for the analysis of naphthenic acid fraction compounds(NAFCs) of oil sands process-affected water(OSPW). A standard mixture of amine-derivatized naphthenic acids is injected directly onto the CE column and analyzed by CE–MS in less than 15 min. Time of flight MS analysis(TOFMS), optimized for high molecular weight ions, showed NAFCs between 250 and 800 m/z. With a quadrupole mass analyzer, only low-molecular weight NAFCs(between 100 and 450 m/z) are visible under our experimental conditions. Derivatization of NAFCs consisted of two-step amidation reactions mediated by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC), or mediated by a mixture of EDC and N-hydroxysuccinimide, in dimethyl sulfoxide, dichloromethane or ethyl acetate. The optimum background electrolyte composition was determined to be 30%(V/V) methanol in water and 2%(V/V) formic acid. NAFCs extracted from OSPW in the Athabasca oil sands region were used to demonstrate the feasibility of CE–MS for the analysis of NAFCs in environmental samples, showing that the labeled naphthenic acids are in the mass range of 350 to 1500 m/z. 相似文献
717.
718.
The Clean Development Mechanism (CDM) is a facility for trading `certified emission reductions (CERs) between developing and developed countries, thus saving non-renewable carbon emissions by promoting renewable energy, energy efficiency and/or carbon sequestration projects in LDC's. The purpose of the CDM is to help these latter countries meet their obligations under the Kyoto Protocol while at the same time promoting “sustainable” development in the former countries, thereby reducing the build-up of greenhouse gases (GHG). This paper examines the progress in achieving a workable CDM in time for the first commitment period (2008–2012), and the kinds of initiatives that can be pursued in the agricultural, land-use and forestry sector in tropical countries. The critical element for the success of the CDM is the participation of a broad cross-section of buyers (ultimately from developed countries) and sellers (from developing countries) of CERs. Trading is the final step, which starts with project formulation, through successful implementation and then certification. This paper lays out a market-based framework for promoting CDM transactions between private sector project developers and traders and public sector policy makers, with regulators, governed by CDM rules, overseeing the smooth running of the CDM. However, as there are numerous players; it is proposed that trial CDM projects be demonstrated with the support of National/International bodies to iron out the problems and come up with practical solutions so that carbon trading can become a reality. Most rules for the CDM were clarified at the 7th Conference of Parties (CP) in October/November of 2001 in Marrakesh. An executive Board (EB) was appointed and this EB is in charge of proposing workable ground rules to promote the CDM. These have to be submitted for approval by the 8th CP in late 2002. Three broad kinds of projects qualify for the CDM, these are: renewable energy projects that will be alternatives to fossil fuel projects; sequestration projects that offset GHG emissions; and energy efficient projects that will decrease the emissions of GHG. It is possible to have a combination of these initiatives. A fourth type covering GHG reduction is omitted. As elaborated in the text, in order to qualify for the CDM, the proposed projects may have to have additional costs when compared to the alternative(s). Two time frames have been agreed for CDM projects to qualify for the first commitment period, namely 7 years (with an option of two 7-year renewals) and 10 years. Also, for land-use, land-use change and forestry projects only afforestation/reforestation initiatives are recognized as being permissible for the first commitment period. These rules seem rather shortsighted, as forestry and/or renewable energy projects usually require more than 21 years to be fully effective. Also, the major cause of deforestation is clearing land for agriculture, not harvesting wood. Therefore, improving agricultural productivity may be the best way to reduce deforestation and its subsequent release of GHGs. These conditionalities should be re-examined when rules for the second commitment period are decided. However, various agricultural and land-use projects are discussed under the existing guidelines which could qualify as CDM projects in the first period. 相似文献
719.
Matthew Edwards Fiona McKenzie Stephen O'Callaghan David Somerset Phillip Woodford Jillian Spilsbury Michael Fietz Janice Fletcher 《黑龙江环境通报》2006,26(10):985-988
Blood was obtained by cordocentesis from a fetus with non-immune hydrops demonstrated by ultrasound scanning at 27 weeks' gestation. Abnormalities of serum transferrin isoelectric focussing (IEF) were identified, characteristic of a congenital disorder of glycosylation type I (CDG-Ia). A diagnosis of CDG-Ia was confirmed by enzyme analysis of cultured amniocytes. This is the first report of CDG-Ia diagnosed by serum analysis in a fetus. Previous reports have warned that diagnostic abnormalities do not appear in serum until several weeks after birth. The sensitivity of cordocentesis transferrin IEF is unknown but is less than 100% effective because cases have been diagnosed postnatally after normal prenatal or neonatal studies. Enzyme analysis or mutation analysis is required for diagnosis of congenital disorder of glycosylation (CDGs) regardless of whether a diagnostic transferrin pattern is identified prenatally. The analysis of a small sample of serum, from cordocentesis, performed to check for fetal anemia, simplified the investigation, diagnosis, and genetic counselling of a case of non-immune hydrops detected at 27 weeks' gestation. This might be a useful test for other cases in these circumstances, as fetal blood is usually collected to check for anemia. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
720.
R David Holbrook Matthew S Wagner Christine M Mahoney Scott A Wight 《Water environment research》2006,78(4):381-391
Environmental scanning electron microscopy (ESEM) with an energy-dispersive X-ray spectrometer (EDS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were demonstrated to be useful analytical tools for investigating surface and bulk components of individual floc particles from both full- and bench-scale activated sludge systems. Detailed surface imaging of various hydrated biological floc particles by ESEM revealed substantial differences in surface features between treatment systems, while EDS identified spatial differences in the iron and the aluminum distributions. The ToF-SIMS spectra had signature fragments of protein and polysaccharide material from the floc surface, suggesting that this technique is capable of surface profiling extracellular polymeric substances. Principal-component analysis of the positive ion ToF-SIMS spectra from the mixed-liquor-suspended solid (MLSS) samples and reference aquatic organic materials found slight differences between the full- and bench-scale MLSS surface properties but substantial differences among MLSS and treated effluent from the same facility. 相似文献