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排序方式: 共有900条查询结果,搜索用时 62 毫秒
891.
Julian Adolphs Frank Kleinjung Jorge Numata Hans Mielke Klaus Abraham Helmut Schafft Christine Müller-Graf Matthias Greiner 《Chemosphere》2013
When food producing animals are contaminated with PCDD/F congeners, information on the contaminant’s concentration in the bodies of the animals at time of slaughter is needed for risk management purposes. We have developed a mathematical model for the kinetics of PCDD/Fs in growing pigs in case of contaminated feed fed for a limited duration of time. This model allows the prediction of concentrations in body fat. It considers absorption fractions of PCDD/Fs, clearance by metabolism, dilution by growth and excretion through fecal fat. The model parameters were calibrated by fitting the model to experimental data. On the basis of this toxicokinetic model a probabilistic model has been constructed. The probabilistic model handles the parameters with appropriate probability distributions and Monte-Carlo simulation technique, providing for realistic situations with many animals and a range of contaminations and feeding intervals. We applied the new model to describe the German dioxin incident of winter 2010/2011 and discuss its viability as decision tool. The approach demonstrated here is a showcase how a risk assessment in the case of contaminated feeding can be performed. 相似文献
892.
Frank J. Schenck Vinetta Howard‐King 《Journal of environmental science and health. Part. B》2013,48(1):1-12
Abstract A multiresidue solid‐phase extraction (SPE) method for the isolation and subsequent gas Chromatographie determination of organochlorine and organophosphorus pesticide residues in low‐moisture, nonfatty products is described. Residues are extracted from samples with an acetonitrile/water mixture. Cleanup of the extract is performed using graphitized carbon black and anion exchange SPE columns, and analysis is performed by gas chromatography with Hall electrolytic conductivity and flame photometric detection. Recovery data was obtained by fortifying corn, oats and wheat with pesticides. The average recoveries were 79–123% for eight organochlorine and 51–122% for 28 organophosphorus pesticide residues. The limit of quantitation for chlorpyriphos was 0.05 ppm using the Hall electrolytic conductivity detector and <0.005 ppm using the flame photometric detector. 相似文献
893.
Frank F. Scherr Ajit K. Sarmah 《Journal of environmental science and health. Part. B》2013,48(8):763-772
A simple and robust analytical method was developed to simultaneously detect and quantify 17β-estradiol (E2), estrone (E1), 17β-estradiol-3-sulphate (E2-3S), and estrone-3-sulphate (E1-3S) in aqueous solutions (calcium chloride and artificial urine solutions) and agricultural soils using high performance liquid chromatography and UV detection. The standards for all four compounds were linear in the range of 0.01 to 1.0 μg mL?1 (n = 6) and 1.0 to 20 μg mL?1 (n = 6), respectively, with correlation coefficients > 0.999. The on-column limits of detection at an injection volume of 50 μL and S/N (signal: noise) ratio of 3 were: 9.0 ng mL?1, 10 ng mL?1, 5.0 ng mL?1, and 7.0 ng mL?1 for E2-3S, E1-3S, E2 and E1, respectively. The limit of detection and quantification in artificial urine solution and CaCl2 solution was 1.0 ng mL?1 for all four compounds. Method detection limits for the compounds in the 3 soils ranged from 2 to 2.4 ng g?1 (E2-3S and E1-3S), and 1.0 to 2.9 ng g?1 (E2 and E1), respectively. 相似文献
894.
The Concept of Farm Animal Welfare: Citizen Perceptions and Stakeholder Opinion in Flanders, Belgium
Filiep Vanhonacker Wim Verbeke Els Van Poucke Zuzanna Pieniak Griet Nijs Frank Tuyttens 《Journal of Agricultural and Environmental Ethics》2012,25(1):79-101
Several attempts to conceptualize farm animal welfare have been criticized for diverging reasons, among them often the failure
to incorporate the public concern and opinion. This paper’s objective is to develop a conception of farm animal welfare that
starts from the public’s perception and integrates the opinion of different stakeholder representatives, thus following a
fork-to-farm approach. Four qualitative citizen focus group discussions were used to develop a quantitative questionnaire,
which has been completed by a representative sample of Flemish citizens (n = 459). Exploratory and confirmatory factor analyses were applied to develop a conception of farm animal welfare starting
from an extended list of aspects that relate to animal production and associate with farm animal welfare in the public’s perception.
In depth interviews with stakeholder representatives were used to match and adapt the structure of the animal welfare conception
model. The resulting conception revealed seven dimensions grouped in two different levels. Three dimensions were animal-based:
“Suffering and Stress,” “Ability to Engage in Natural Behavior,” and “Animal Health.” Four dimensions were resource-based:
“Housing and Barn climate,” “Transport and Slaughter,” “Feed and Water,” and “Human-Animal Relationship.” This conception
is distinct from earlier attempts since it is based on public perceptions; it addresses the opinion of different stakeholders,
and it distinguishes empirically between animal-based and resource-based dimensions in the conceptualization of farm animal
welfare. The relevancy of a popular definition is supported by the present demand oriented economy, in which animal welfare
is a non-trade concern, and mainly left to the market where consumers still mainly act as individuals who calculate and weigh
pros and cons. 相似文献
895.
Paul E. Ouboter Gwendolyn A. Landburg Jan H. M. Quik Jan H. A. Mol Frank van der Lugt 《Ambio》2012,41(8):873-882
Mercury levels in sediment and predatory fish were measured for 53 localities in Suriname. The average mercury level in bottom sediment surpassed the Canadian standard for sediment in most localities, except the coastal plains. Of the predatory fish, 41 % had a mercury level above the European Union standard for human consumption of 0.5 μg g−1. Highest mercury levels were found in fish from the Brokopondo Reservoir and from the Upper Coppename River. High levels of mercury in fish in pristine areas are explained by atmospheric transportation of mercury with the northeastern trade winds followed by wet deposition. Contrary to gold mining areas, where mercury is bound to drifting sediments, in “pristine” areas the mercury is freely available for bio-accumulation and uptake. Impacts on piscivorous reptiles, birds, and mammals are unknown, but likely to be negative. 相似文献
896.
Release of methane from aerobic soil: an indication of a novel chemical natural process? 总被引:2,自引:0,他引:2
Methane (CH4) formation under aerobic conditions has been intensely debated, especially since the discovery of CH4 generation by both dried plant material and living plants. In this study we test the hypothesis that non-microbial CH4 formation also occurs in soils. All lyophilised soil samples investigated under aerobic conditions released CH4 at temperatures ranging from 30 to 70 °C exceeding that allowing normal enzymatic activity to proceed. No emissions were observed for single mineral soil components such as quartz sand, clay mineral and iron oxide. Methane release rates from the soils investigated were found to increase both with increasing temperature and higher organic carbon content. Addition of water to dried soils increased CH4 release rates up to 8-fold those observed with the dried material. Our results suggest the existence of a chemical process in soils that produces CH4 under aerobic conditions, a finding which has not been hitherto reported. 相似文献
897.
Methyl chloride emissions from halophyte leaf litter: dependence on temperature and chloride content
Derendorp L Wishkerman A Keppler F McRoberts C Holzinger R Röckmann T 《Chemosphere》2012,87(5):483-489
Methyl chloride (CH3Cl) is the most abundant natural chlorine containing compound in the atmosphere, and responsible for a significant fraction of stratospheric ozone destruction. Understanding the global CH3Cl budget is therefore of great importance. However, the strength of the individual sources and sinks is still uncertain. Leaf litter is a potentially important source of methyl chloride, but factors controlling the emissions are unclear. This study investigated CH3Cl emissions from leaf litter of twelve halophyte species. The emissions were not due to biological activity, and emission rates varied between halophyte species up to two orders of magnitude. For all species, the CH3Cl emission rates increased with temperature following the Arrhenius relation. Activation energies were similar for all investigated plant species, indicating that even though emissions vary largely between plant species, their response to changing temperatures is similar. The chloride and methoxyl group contents of the leaf litter samples were determined, but those parameters were not significantly correlated to the CH3Cl emission rate. 相似文献
898.
This work deals with a new abiotic oxidation process designed as a suitable pre-treatment step within a biological depuration of wastewater containing phenol or its derivatives (o-cresol, 2-chlorophenol and p-nitrophenol) or aniline. The reaction was carried out in a stirred tank reactor at 20 degrees C and atmospheric pressure in presence of the organic compound, 150mgl(-1), zero valent iron particles (10g), ethylenediamine tetraacetic acid (EDTA, 101mgl(-1)) and air. The experimental results show that 85% of phenol conversion can be achieved after 360min. 2-Chlorophenol was found to be more easily degradable and it is completely eliminated after 300min. The oxidation of o-cresol and aniline behaved more closely to phenol obtaining after 360min 70% and 68% of conversion respectively. p-Nitrophenol was a very refractory compound, giving only 28% of conversion after 360min. Moreover, the influence of some operating variables was studied over the following ranges: temperature from 20 to 50 degrees C, initial phenol concentration from 150 to 1000mgl(-1), EDTA concentration from 50 to 200mgl(-1) and iron particles from 5 to 20g. As expected, temperature strongly enhances phenol conversion. Also, an increase of the catalyst to phenol ratio or the iron or EDTA to phenol ratio improves the reaction rate. A preliminary kinetic analysis of the data shown that the rate of phenol disappearance is not first order with respect to the phenol. 相似文献
899.
Vyas Nimish B. Rattner Barnett A. Lockhart J. Michael Hulse Craig S. Rice Clifford P. Kuncir Frank Kritz Kevin 《Environmental science and pollution research international》2022,29(49):74024-74037
Environmental Science and Pollution Research - An important component of assessing the hazards of anticoagulant rodenticides to non-target wildlife is observations in exposed free-ranging... 相似文献
900.
Musah Mohammed Mensah Isaac Adjei Alfred Morrison Mahmood Haider Murshed Muntasir Omari-Sasu Akoto Yaw Boateng Frank Nyeadi Joseph Dery Coffie Cephas Paa Kwesi 《Environmental science and pollution research international》2022,29(21):31330-31347
Environmental Science and Pollution Research - One of the most commonly debated concerns regarding foreign direct investment inflows is the associated environmental adversities that accompany the... 相似文献