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991.
Aerial measurement of radioxenon concentration off the west coast of Vancouver Island following the Fukushima reactor accident 总被引:1,自引:0,他引:1
Sinclair LE Seywerd HC Fortin R Carson JM Saull PR Coyle MJ Van Brabant RA Buckle JL Desjardins SM Hall RM 《Journal of environmental radioactivity》2011,102(11):1018-1023
In response to the Fukushima nuclear reactor accident, on March 20th, 2011, Natural Resources Canada conducted aerial radiation surveys over water just off the west coast of Vancouver Island. Dose-rate levels were found to be consistent with background radiation, however a clear signal due to 133Xe was observed. Methods to extract 133Xe count rates from the measured spectra, and to determine the corresponding 133Xe activity concentration, were developed. The measurements indicate that 133Xe concentrations on average lie in the range of 30-70 Bq/m3. 相似文献
992.
Sediment and phosphorus (P) transport from the Minnesota River Basin to Lake Pepin on the upper Mississippi River has garnered much attention in recent years. However, there is lack of data on the extent of sediment and P contributions from riverbanks vis-à-vis uplands and ravines. Using two light detection and ranging (lidar) data sets taken in 2005 and 2009, a study was undertaken to quantify sediment and associated P losses from riverbanks in Blue Earth County, Minnesota. Volume change in river valleys as a result of bank erosion amounted to 1.71 million m over 4 yr. Volume change closely followed the trend: the Blue Earth River > the Minnesota River at the county's northern edge > the Le Sueur River > the Maple River > the Watonwan River > the Big Cobb River > Perch Creek > Little Cobb River. Using fine sediment content (silt + clay) and bulk density of 37 bank samples representing three parent materials, we estimate bank erosion contributions of 48 to 79% of the measured total suspended solids at the mouth of the Blue Earth and the Le Sueur rivers. Corresponding soluble P and total P contributions ranged from 0.13 to 0.20% and 40 to 49%, respectively. Although tall banks (>3 m high) accounted for 33% of the total length and 63% of the total area, they accounted for 75% of the volume change in river valleys. We conclude that multitemporal lidar data sets are useful in estimating bank erosion and associated P contributions over large scales, and for riverbanks that are not readily accessible for conventional surveying equipment. 相似文献
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P.J. Somerfield M. Atkins S.G. Bolam K.R. Clarke E. Garnacho H.L. Rees R. Smith R.M. Warwick 《Marine Biology》2006,148(6):1231-1240
Phylum-level meta-analysis was applied to 192 samples from a variety of dredgings disposal and relocation sites around the
coast of England and Wales. No consistent relationship was found between the disturbance status of macrobenthic communities
within disposal sites and the nature or amount of dredgings disposed. Differences between samples within and outside disposal
sites were generally smaller than differences between different sites and various patterns of impact were detected. It is
concluded that dredgings disposal has two contrasting impacts on benthic communities. One, associated with organic enrichment,
leads to communities dominated by annelids and nematodes. The other, associated with intense physical disturbance, favours
large motile or armoured forms, such as bivalve molluscs and crustaceans. These effects may act antagonistically, and in a
phylum-level meta-analysis may cancel each other out. None of the samples examined from offshore disposal sites was grossly
disturbed, in terms of the proportional contribution to production from different phyla, and overall most samples ranged from
moderately disturbed to undisturbed. The ecological impacts associated with the intertidal placement of material (beneficial
use schemes) were comparable to those observed for the conventional sea disposal sites. 相似文献
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998.
J Rivas E Rodríguez F J Beltrán J F García-Araya P Alvarez 《Journal of environmental science and health. Part. B》2001,36(3):317-330
Simazine, [2-chloro, 4,6-bis(ethylamino)-1,3,5-s-triazine], a common herbicide typically found in surface and ground water was ozonised by using catalytic amounts of Mn(II) and Fe(II). An optimum value for metal concentration was found in the process. Some inhibition of the simazine degradation rate was observed when these metals were added above the optimum concentration. The pH of the reaction media played a significant role in the simazine oxidation rate. Thus, an increase in simazine conversion was observed when the pH was raised from 5 to 9. However, the catalytic effect of added manganese was negligible at the highest pH used in this study (pH 9). The beneficial influence of Fe(II) was also observed when utilising the combination of ozone and hydrogen peroxide. Contrarily, Mn(II) presented a negative influence on simazine conversion when using this oxidation technology. 相似文献
999.
Bacterial bioabsorption of nickel from industrial cooling water 总被引:1,自引:0,他引:1
Three bacterial strains tolerant to the presence of 100 mg litre(-1) nickel ions were isolated from a water reclamation system. Each organism was tested for ability to accumulate nickel at the above-mentioned concentration. The organism capable of maximum nickel accumulation was identified as an Enterobacter sp. and intracellular nickel deposition by this microorganism was determined using energy dispersive X-ray analysis (EDAX) and transmission electron microscopy. A metal-staining technique for light microscopy was developed. Further studies revealed that growth and glucose utilisation by this isolate was inhibited in culture by nickel. 相似文献
1000.
In this study of 43 student project teams, we tested a multi‐level mediation model of the relationship between dissimilarity in conscientiousness, team temporal processes, and team member satisfaction. We distinguished between individual‐level dissimilarity in conscientiousness (i.e., the distance between an individual member and his or her team mates), and team‐level dissimilarity in conscientiousness (i.e., the overall dissimilarity within the team). Individual‐level dissimilarity in conscientiousness had a direct negative effect on team members' satisfaction with the team, but did not affect their satisfaction with the team's performance. Team‐level dissimilarity in conscientiousness indirectly affected both types of satisfaction negatively as it impeded early agreement about the temporal aspects of task execution, which, in turn, hindered coordinated action in later stages of team task execution. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献