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911.
John H. Martin Alan R. Collins Robert G. Diener P.E. 《Journal of the Air & Waste Management Association (1995)》2013,63(11):864-870
Abstract This article reports on development of a protocol for characterizing municipal solid waste (MSW). This protocol is similar to that recommended by the American Society for Testing and Materials but includes a distinction between pure and mixed loads of MSW. Thirteen component categories were used with a focus on material feed stock for composting, recycling, and reuse. The required number of samples was determined to achieve a 80%, 90%, and 95% statistical accuracy for characterizing MSW categories at 1% and 2% sampling error. This study found that a maximum of 25 randomly collected samples of 200 pounds will reflect each component category of mixed load MSW with at least a 95% confidence level and 2% error. This protocol was successfully tested in Monongalia County, West Virginia, to provide a “snapshot” MSW characterization during early summer. 相似文献
912.
Moine C Gloaguen V Gloaguen JM Granet R Krausz P 《Journal of environmental science and health. Part. B》2004,39(4):627-640
Esterification of hemicelluloses of the xylan family was performed in order to produce hydrophobic films. Acylation reactions were carried out with lauroyl chloride in the N,N-dimethylacetamide/lithium chloride homogeneous system using 4-dimethylaminopyridine as activator and were induced by microwave irradiation. In the experimental conditions used, 108 and 172% mass ratios were obtained for the dodecyl-grafted xylan and heteroxylan, respectively. The degrees of substitution (DS) were 1.3 (maximum 2) for xylan and 1.2 (maximum 2.1) for heteroxylan. These products were further characterized by FT-IR spectroscopy. The mechanical and thermomechanical behavior of this new family of hydrophobic films were analyzed and compared to those obtained from cellulose with a similar DS by the means of tensile tests. Our results indicate that the dodecyl-grafted xylan film presents the best rigidity-resistance to traction ratio. 相似文献
913.
Polybrominated diphenyl ethers (PBDEs) are flame retardants added to a multitude of products to reduce flammability. PBDEs have been widely detected and quantified in biota and humans in many industrialised countries from the Northern Hemisphere. However data concerning the levels of these compounds in the Australian population and environment remain limited. The objectives of this study were to determine PBDE concentrations and congener profiles in Australian human milk and compare this to concentrations found in other countries. Pooled human milk samples obtained from mothers residing in 12 regions of Australia were analysed by HRGC/HRMS for 18 PBDE congeners. In total, 157 human milk samples collected in 2002 and 2003 were divided into 17 regional pools. PBDEs were detected in all pools of human milk from Australia. The mean+/-standard deviation and median summation operatorPBDE concentrations were 11.1+/-3.2 and 11.0 ng g(-1) lipid, respectively with a range of 6.1-18.7 ng g(-1) lipid. The congener profile was dominated by BDE-47 followed by BDE-99, -100, -153, -154 and -183. Regional differences were evaluated, but no trends were observed. The data suggest regional differences are likely to be small if they exist at all. The concentrations of PBDEs found in Australian human milk were lower than those reported from North America but higher than those reported from Europe and Asia. Our results suggest that the exposure pathways which contribute to the PBDE body burden in the Australian population require a better understanding in order to determine future policy regarding their use and disposal. 相似文献
914.
自20世纪中叶以来,五大湖区的水生食物网就已受到多氯联苯化合物(PCBs)的污染。对于长寿命鱼类,如湖鲟(Acipenser fulvescens),由于缺乏该物种的相对敏感性信息,一直无法确定其PCB暴露的风险。本文的研究目标就是评估湖鲟早期生命阶段对3,3''4,4''5-五氯联苯(PCB-126)或2,3,7,8-四氯二苯并-p-二恶英(TCDD)暴露的敏感性。死亡率、生长、形态和组织病理学、游泳能力和活动水平都被用作评估终点。心包和卵黄囊水肿、管状心脏、卵黄囊出血和体长较小是TCDD和PCB-126暴露中最常见的病理症状,早在受精4 d后就开始出现,其中许多的病理都以一种剂量依赖的方式发生。湖鲟体内PCB-126和TCDD的半致死剂量分别为5.4 ng/g egg(95%置信区间,3.9-7.4 ng/g egg)和0.61 ng/g egg (0.47-0.82 ng/g egg)。由此产生的PCB-126的相对强度因子(0.11)远大于世界卫生组织对鱼的估计值(毒性当量因子=0.005),这表明目前的风险评估可能低估了PCB对湖鲟的毒性。在受精60 d后,从半致死剂量中幸存的湖鲟的游泳活性和耐力均有所下降。阈值和半数效应毒性值表明,与在北美发现的另一种鲟鱼属Scaphirhynchu相比,湖鲟对PCB和TCDD更为敏感。事实上,在大湖区和其他地方的湖鲟种群都容易受到PCB/ TCDD诱导,使胚胎发育受到影响,游泳能力下降。
精选自Tillitt, D. E., Buckler, J. A., Nicks, D. K., Candrl, J. S., Claunch, R. A., Gale, R. W., Puglis, H. J., Little, E. E., Linbo, T. L. and Baker, M. (2017), Sensitivity of lake sturgeon (Acipenser fulvescens) early life stages to 2,3,7,8-tetrachlorodibenzo-P-dioxin and 3,3′,4,4′,5-pentachlorobiphenyl. Environmental Toxicology and Chemistry, 36: 988–998. doi: 10.1002/etc.3614
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3614/full 相似文献
915.
Margaret Mulvey Charles Lydeard Debra L. Pyer Kimberly M. Hicks Jayne Brim-Box James D. Williams & Robert S. Butler 《Conservation biology》1997,11(4):868-878
Freshwater bivalves are among the most endangered groups of organisms in North America. Efforts to protect the declining mussel fauna are confounded by ambiguities associated with recognition of distinct evolutionary entities or species. This, in part, is due to the paucity of reliable morphological characters for differentiating taxa. We have employed allozymes and DNA sequence data to search for diagnosably distinct evolutionary entities within two problematic genera of unionid mussels, Amblema and Megalonaias. Within the genus Amblema three species are recognized based on our DNA sequence data for the mitochondrial 16S rRNA and allozyme data (Amblema neislerii, A. plicata, and A. elliotti). Only one taxonomically distinct entity is recognized within the genus Megalonaias—M. nervosa. Megalonaias boykiniana of the Apalachicolan Region is not diagnosable and does not warrant specific taxonomic status. Interestingly, Megalonaias from west of the Mississippi River, including the Mississippi, exhibited an allozyme and mtDNA haplotype frequency shift suggestive of an east-west dichotomy. The results of this study eliminate one subspecies of Amblema and increase the range of A. plicata. This should not affect the conservation status of "currently stable" assigned to A. plicata by Williams et al. (1993). The conservation status of A. elliotti needs to be reexamined because its distribution appears to be limited to the Coosa River System in Alabama and Georgia. 相似文献
916.
Duncan J Golicher Robert B O'Hara Lorena Ruíz-Montoya Luis Cayuela 《Ecological applications》2006,16(1):202-212
Bayesian methods incorporate prior knowledge into a statistical analysis. This prior knowledge is usually restricted to assumptions regarding the form of probability distributions of the parameters of interest, leaving their values to be determined mainly through the data. Here we show how a Bayesian approach can be applied to the problem of drawing inference regarding species abundance distributions and comparing diversity indices between sites. The classic log series and the lognormal models of relative- abundance distribution are apparently quite different in form. The first is a sampling distribution while the other is a model of abundance of the underlying population. Bayesian methods help unite these two models in a common framework. Markov chain Monte Carlo simulation can be used to fit both distributions as small hierarchical models with shared common assumptions. Sampling error can be assumed to follow a Poisson distribution. Species not found in a sample, but suspected to be present in the region or community of interest, can be given zero abundance. This not only simplifies the process of model fitting, but also provides a convenient way of calculating confidence intervals for diversity indices. The method is especially useful when a comparison of species diversity between sites with different sample sizes is the key motivation behind the research. We illustrate the potential of the approach using data on fruit-feeding butterflies in southern Mexico. We conclude that, once all assumptions have been made transparent, a single data set may provide support for the belief that diversity is negatively affected by anthropogenic forest disturbance. Bayesian methods help to apply theory regarding the distribution of abundance in ecological communities to applied conservation. 相似文献
917.
George H. Nieswand Robert M. Hordon Theodore B. Shelton Budd B. Chavooshian Steven Blarr 《Journal of the American Water Resources Association》1990,26(6):959-966
ABSTRACT: Buffer strips are undisturbed, naturally vegetated zones around water supply reservoirs and their tributaries that are a recognized and integral aspect of watershed management. These strips can be very effective in protecting the quality of public potable water supply reservoirs by removing sediment and associated pollutants, reducing bank erosion, and displacing activities from the water's edge that represent potential sources of nonpoint source pollutant generation. As part of a comprehensive watershed management protect for the State of New Jersey, a parameter-based buffer strip model was developed for application to all watersheds above water supply intakes or reservoirs. Input requirements for the model include a combination of slope, width, and time of travel. The application of the model to a watershed in New Jersey with a recommended buffer strip width that ranges from 50 to 300 feet, depending upon a number of assumptions, results in from 6 to 13 percent of the watershed above the reservoir being occupied by the buffer. 相似文献
918.
Robert V Rohli John M. Grymes 《Journal of the American Water Resources Association》1995,31(1):97-107
ABSTRACT: A one-layer decreasing-availability monthly water balance model is used to estimate monthly surplus that flows into the Lake Pontchartrain Basin from the Amite, Tickfaw, Natalbany, Tangipahoa, and Tchefuncte Rivers for water years 1949 through 1990. The modeled annual surplus for each drainage basin is compared to gauged annual discharge obtained from the United States Geological Survey. This provides an estimate of the differential success of the model over watersheds of various sizes, and also suggests appropriate adjustment factors to be used in future water balance analyses of similar basins in humid subtropical climate regions. Results show that annual surplus values agree well with the USGS values, after an annual adjustment of about 140 mm (11 to 28 percent of the basin surplus) is subtracted from the annual modeled totals to compensate for overestimation by the model. However, inter-annual variability is high in the annual cycles. Winter and spring discharges can also be modeled successfully. 相似文献
919.
A Method for Setting the Size of Plant Conservation Target Areas 总被引:3,自引:0,他引:3
Mark A. Burgman Hugh P. Possingham † A. Jasmyn J. Lynch ‡ David A. Keith § Michael A. McCarthy Stephen D. Hopper †† Wendy L. Drury ‡‡ Jason A. Passioura ‡ Robert J. Devries§§ 《Conservation biology》2001,15(3):603-616
Abstract: Realistic time frames in which management decisions are made often preclude the completion of the detailed analyses necessary for conservation planning. Under these circumstances, efficient alternatives may assist in approximating the results of more thorough studies that require extensive resources and time. We outline a set of concepts and formulas that may be used in lieu of detailed population viability analyses and habitat modeling exercises to estimate the protected areas required to provide desirable conservation outcomes for a suite of threatened plant species. We used expert judgment of parameters and assessment of a population size that results in a specified quasiextinction risk based on simple dynamic models. The area required to support a population of this size is adjusted to take into account deterministic and stochastic human influences, including small-scale disturbance, deterministic trends such as habitat loss, and changes in population density through processes such as predation and competition. We set targets for different disturbance regimes and geographic regions. We applied our methods to Banksia cuneata, Boronia keysii, and Parsonsia dorrigoensis, resulting in target areas for conservation of 1102, 733, and 1084 ha, respectively. These results provide guidance on target areas and priorities for conservation strategies. 相似文献
920.
Toward an integrated analysis of mitigation and adaptation: some preliminary findings 总被引:4,自引:0,他引:4
Thomas J. Wilbanks Paul Leiby Robert Perlack J. Timothy Ensminger Sherry B. Wright 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):713-725
Between 1999 and 2003, the Oak Ridge National Laboratory (ORNL) made a preliminary effort to integrate an analysis of mitigation
and adaptation to climate change impact vulnerabilities in two ways: top-down and bottom-up. This paper briefly describes
these early experiments and summarizes their findings, both about climate change vulnerability reduction and about the challenges
of integrated analysis, expanding upon results previously reported [Wilbanks et al. (Environment 45/5:28–38, 2003); ORNL (Integrated analysis of mitigation and adaptation as responses to concerns about impacts of global climate change,
ORNL Working paper 2003); ORNL and CUSAT 2003; Wilbanks 2005].
The U.S Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged 相似文献