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981.
R. K. M. Jayanty J. A. Sokash G. B. Howe R. G. Fuerst T. J. Logan M. R. Midgett 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1342-1346
A simple, inexpensive, and accurate technique for evaluating or auditing the sampling, recovery, and analytical phases of EPA Source Reference Method 25 has been developed. The technique involves spiking a U-shaped stainless steel cartridge containing Tenax® with known quantities of selected organic compounds and thermally desorbing them at temperatures from 160°C to 180°C to generate organic vapors quantitatively. The major advantages of this technique are that no other measurement methods can be used to determine the generated organic concentrations in lieu of Method 25; and that the cartridge can easily be taken to the field for evaluation. The organic compounds generated in test runs are collected and analyzed using the Method 25 procedure. The generation of organics is quantitative and recoveries were found to be 100 ± 10%. The time required for desorption of the majority of organics is generally less than forty-five minutes at a flow rate of 100 mL/min; however, based on laboratory experience the recommended sampling time is sixty minutes. These spiked cartridges are stable at room temperature over a two-month period. Results of interlaboratory studies showed close agreement with the expected concentrations based on calculations from the mass loadings and sample volumes. 相似文献
982.
Adaptive capacity determinants in developed states: examples from the Nordic countries and Russia 总被引:1,自引:1,他引:0
E. Carina H. Keskitalo Halvor Dannevig Grete K. Hovelsrud Jennifer J. West Åsa Gerger Swartling 《Regional Environmental Change》2011,11(3):579-592
Adaptive capacity in a community context has so far mainly been studied in developing countries as well as indigenous communities
in the industrialised world. This article adds to that literature through reviewing studies undertaken in the Nordic countries
and Russia, highlighting the ways in which general determinants of adaptive capacity play out in Northern, industrialised
contexts. The paper illustrates that the determinants of adaptive capacity in industrialised states exhibit systematic differences
from mixed subsistence-cash based communities such as those found in Arctic Canada. We discuss in particular the importance
of economic resources in a market-based system, technological competition, and infrastructure, in determining adaptive capacity
of natural resource-dependent communities in the Nordic countries and Russia. The paper also illustrates differences in adaptive
capacity within the case study region, including between peripheral and central locations with regard to economic resources
and diversification possibilities, and between Nordic and Russian cases with regard to infrastructure and technology access.
The findings indicate that understanding of determinants of adaptive capacity in resource-dependent communities would benefit
from both further contextualisation and broad comparison, across different types of political and administrative systems. 相似文献
983.
Long-term (1860–2010) catchment mass balance calculations rely on models and assumptions which are sources of uncertainty
in acidification assessments. In this article, we report on an application of MAGIC to model acidification at the four Swedish
IM forested catchments that have been subject to differing degrees of acidification stress. Uncertainties in the modeled mass
balances were mainly associated with the deposition scenario and assumptions about sulfate adsorption and soil mass. Estimated
base cation (BC) release rates (weathering) varied in a relatively narrow range of 47–62 or 42–47 meq m−2 year−1, depending on assumptions made about soil cation exchange capacity and base saturation. By varying aluminum solubility or
introducing a dynamic weathering feedback that allowed BC release to increase at more acidic pHs, a systematic effect on predicted
changes in acid neutralizing capacity (ΔANC ca. 10–41 μeq l−1) and pH (ca. ΔpH = 0.1–0.6) at all sites was observed. More robust projections of future changes in pH and ANC are dependent
on reducing uncertainties in BC release rates, the timing, and extent of natural acidification through BC uptake by plants,
temporal changes in soil element pools, and fluxes of Al between compartments. 相似文献
984.
Meghann E. Jarchow Justin W. Rice Rebekah M. Ritson Sarah K. Hargreaves 《Sustainability Science》2011,6(2):253-254
Conference organizers are increasingly making efforts to reduce resource use at conferences, yet few responsibilities are
placed on attendees. We hosted an ecology conference and offered attendees a discount if they took a sustainability pledge
agreeing to reduce their resource use at the conference. In a post-conference survey, 83% of respondents reported fulfilling
the pledge, but 62% indicated that convenience was the biggest obstacle impeding their ability to continue the pledge during
and after the conference. We found great willingness by attendees to reduce resource use at and beyond our conference, and
facilitating their participation was an important part of our success. 相似文献
985.
Combination of divergent active principles to achieve broad-spectrum control is gaining popularity to manage the weed menace in intensive agriculture. However, such application could have non-target impacts on the soil processes affecting soil ecology and environmental interactions. A field experiment was conducted to investigate the impact of separate and combined applications of herbicides bensulfuron methyl and pretilachlor on the emission of N2O and CH4, and related soil and microbial parameters in a flooded alluvial field planted to rice cv Lalat. Single application of the herbicide bensulfuron methyl or pretilachlor resulted in a significant reduction of N2O and CH4 emissions while the combination of these two herbicides distinctly increased N2O and CH4 emissions. Cumulative N2O emissions (kg N2O-N) followed the order of bensulfuron methyl (0.35 kg ha−1) < pretilachlor (0.36 kg ha−1) < control (0.45 kg ha−1) < bensulfuron methyl 0.6% + pretilachlor 6.0% single dose (0.49 kg ha−1) < bensulfuron methyl 0.6% + pretilachlor 6.0% double dose (0.54 kg ha−1). Cumulative CH4 emissions (kg CH4), on the other hand, followed the order of bensulfuron methyl (47.89 kg ha−1) < pretilachlor (73.17 kg ha−1) < bensulfuron methyl 0.6% + pretilachlor 6.0% single dose (93.50 kg ha−1) < control (106.54 kg ha−1) < bensulfuron methyl 0.6% + pretilachlor 6.0% double dose (124.67 kg ha−1). The inhibitory effect of separate application of herbicides bensulfuron methyl 0.6% and pretilachlor 6.0% on N2O emission was linked to lower mineral N, lower denitrifying and nitrifying activity and low denitrifier and nitrifier populations. Inhibitory effect on CH4 emission, on the contrary, was linked to prevention in the drop of redox potential, lower readily mineralizable carbon (RMC) and microbial biomass carbon (MBC) contents as well as lower methanogenic and higher methanotrophic bacterial population. Admittedly, stimulatory effect of combined application of herbicides bensulfuron methyl 0.6% and pretilachlor 6.0% at double dose on N2O and CH4 emission was related to reversal of the identified indicators of inhibition. Results indicate that while individual application of herbicides bensulfuron methyl 0.6% or pretilachlor 6.0% can reduce N2O and CH4 emission from flooded soil planted to rice, their combined application at normal dose can keep the emission at a comparatively lower level with significantly higher grain yield as compared to the herbicides applied alone. 相似文献
986.
Wölz J Grosshans K Streck G Schulze T Rastall A Erdinger L Brack W Fleig M Kühlers D Braunbeck T Hollert H 《Chemosphere》2011,85(5):717-723
Bankside groundwater is widely used as drinking water resource and, therefore, contamination has to be avoided. In the European Union groundwater protection is explicit subject to Water Framework Directive. While groundwater pollution may originate from different sources, this study investigated on impacts via flood events.Groundwater was sampled with increasing distance to the river Rhine near Karlsruhe, Germany. Samples were HPLC-MS-MS analyzed for the river contaminant carbamazepine to indicate river water infiltration, giving permanent presence in 250 m distance to the river (14-47 μg L−1). Following a flood event, concentrations of about 16-20 μg L−1 could also be detected in a distance of 750 m to the river. Furthermore, estrogenic activity as determined with the Yeast Estrogen Screen assay was determined to increase up to a 17β-ethinylestradiol equivalent concentration (E-EQ) = 2.9 ng L−1 near the river, while activity was initially measured following the flood with up to E-EQ = 2.6 ng L−1 in 750 m distance. Detections were delayed with increasing distance to the river indicating river water expansion into the aquifer.Flood suspended matter and floodplain soil were fractionated and analyzed for estrogenic activity in parallel giving up to 1.4 ng g−1 and up to 0.7 ng g−1, respectively. Target analysis focusing on known estrogenic active substances only explained <1% of measured activities.Nevertheless, river water infiltration was shown deep into bankside groundwater, thus, impacting groundwater quality. Therefore, flood events have to be in the focus when aiming for groundwater and drinking water protection as well as for implementation of Water Framework Directive. 相似文献
987.
Partitioning of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS) and perfluorooctane sulfonamide (PFOSA) between water and sediment 总被引:4,自引:0,他引:4
Laboratory partitioning experiments were conducted to elucidate the sorption behaviour and partitioning of perfluoroalkyl compounds (PFCs). Three different sediment types were used and separately spiked with perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS) and perfluorooctane sulfonamide (PFOSA) at low environmentally realistic concentrations. PFOA, PFOS and PFOSA were mainly distributed in the dissolved phase at low suspended solid concentrations, indicating their long-range transport potential in the marine environment. In all cases, the equilibrium isotherms were linear and the organic carbon normalised partition coefficients (KOC) decreased in the following order: PFOSA (log KOC = 4.1 ± 0.35 cm3 g−1) > PFOS (3.7 ± 0.56 cm3 g−1) > PFOA (2.4 ± 0.12 cm3 g−1). The level of organic content had a significant influence on the partitioning. For the sediment with negligible organic content the density of the sediment became the most important factor influencing the partitioning. Ultimately, data on the partitioning of PFCs between aqueous media and suspended solids are essential for modelling their transport and environmental fate. 相似文献
988.
Microcosm experiments to control anaerobic redox conditions when studying the fate of organic micropollutants in aquifer material 总被引:1,自引:0,他引:1
989.
The chemical composition of the odors typical of fires has recently been deciphered. Basically the constituents are mixtures of acetophenone, benzyl alcohol, hydroxylated derivatives of benzaldehyde, methoxylated and/or alkylated phenols and naphthalene. This finding makes it possible to develop objective, practical analytic measurement methods for the burnt smell as a contribution to improving fire damage assessment and remediation monitoring. With the aid of an artificially produced burnt smell and a panel of testers the odor detection threshold of a test mixture was determined olfactometrically to 2 μg m−3. Using a defined burnt-smell atmosphere in a test chamber, analytical methods with active sampling, the adsorbents XAD 7 and TENAX TA, and GC/MS measurement were then optimized and tested with a view to being able to carry out sensitive quantitative measurement of burnt smells. A further practical method with particular application to the qualitative characterization of this odor is based on the use of a new SPME (solid-phase microextraction) field sampler with DVB/CAR/PDMS (divinylbenzene/Carboxen™/polydimethylsiloxane) fibers. 相似文献
990.
Indiscriminate use of agrochemicals worldwide, particularly, persistent organic pollutants (POPs), is of concern. Endosulfan, a POP, is used by various developing/developed nations and is known to adversely affect the development and the hormonal profiles of humans and animals. However, little is known about the molecular players/pathways underlying the adverse effects of endosulfan. We therefore analyzed the global gene expression changes and subsequent adverse effects of endosulfan using Drosophila. We used Drosophila melanogaster keeping in view of its well annotated genome and the wealth of genetic/molecular reagents available for this model organism. We exposed third instar larvae of D. melanogaster to endosulfan (2.0 μg mL−1) for 24 h and using microarray, we identified differential expression of 256 genes in exposed organisms compared to controls. These genes are associated with cellular processes such as development, stress and immune response and metabolism. Microarray results were validated through quantitative PCR and biochemical assay on a subset of genes/proteins. Taking cues from microarray data, we analyzed the effect of endosulfan on development, emergence and survival of the organism. In exposed organisms, we observed deformities in hind-legs, reminiscent of those observed in higher organisms exposed to endosulfan. In addition, we observed delayed and/or reduced emergence in exposed organisms when compared to their respective controls. Together, our studies not only highlight the adverse effects of endosulfan on the organism but also provide an insight into the possible genetic perturbations underlying these effects, which might have potential implications to higher organisms. 相似文献