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Katrine A. Gorham Nicola J. Blake Richard A. VanCuren Henry E. Fuelberg Simone Meinardi Donald R. Blake 《Atmospheric environment (Oxford, England : 1994)》2010,44(19):2271-2279
We present a study of the seasonal and diurnal variability of carbon monoxide and selected volatile organic compounds in the Los Angeles area. Measurements were made during four different nine-day field campaigns in April/May, September, and November, 2007, and February, 2008, at the Mt. Wilson sampling site, which is located at an elevation of approximately 1700 m in the San Gabriel Mountains overlooking Pasadena and the Los Angeles basin. The results were used to characterize the Mt. Wilson site as a representative location for monitoring integrated Los Angeles basin emissions, and, by reference to carbon monoxide emissions, to estimate average annual emissions. The considerable seasonal variability of many hydrocarbons, in both their measured mixing ratios and their relationship to carbon monoxide, was indicative of variable source strengths. Most interestingly, perturbation of C4 hydrocarbon ratios suggested an enhanced role for chlorine chemistry during the month of September, likely as the result of Los Angeles’ coastal location. Such coastal influence was confirmed by observations of enhanced mixing ratios of marine halocarbons, as well as air mass back trajectories. 相似文献
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How to Constrain Multi‐Objective Calibrations of the SWAT Model Using Water Balance Components 下载免费PDF全文
Matthias Pfannerstill Katrin Bieger Björn Guse David D. Bosch Nicola Fohrer Jeffrey G. Arnold 《Journal of the American Water Resources Association》2017,53(3):532-546
Accurate discharge simulation is one of the most common objectives of hydrological modeling studies. However, a good simulation of discharge is not necessarily the result of a realistic simulation of hydrological processes within the catchment. We propose an evaluation framework that considers both discharge and water balance components as evaluation criteria for calibration of the Soil and Water Assessment Tool (SWAT). In this study, we integrated average annual values of surface runoff, groundwater flow, and evapotranspiration in the model evaluation procedure to constrain the selection of good model runs for the Little River Experimental Watershed in Georgia, United States. For evaluating water balance and discharge dynamics, the Nash‐Sutcliffe efficiency (NSE) and percent bias (PBIAS) were used. In addition, the ratio of root mean square error and standard deviation of measured data (RSR) was calculated for individual segments of the flow duration curve to identify the best model runs in terms of discharge magnitude. Our results indicate that good statistics for discharge do not guarantee realistic simulations of individual water balance components. Therefore, we recommend constraining the ranges of water balance components to achieve a more realistic simulation of the entire hydrological system, even if tradeoffs between good statistics for discharge simulations and reasonable amounts of the water balance components are unavoidable. Editor's note : This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series. 相似文献
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Daniela Iannazzo Alessandro Pistone Ida Ziccarelli Claudia Espro Signorino Galvagno Salvatore V Giofré Roberto Romeo Nicola Cicero Giuseppe D Bua Giuseppe Lanza Laura Legnani Maria A Chiacchio 《Environmental science and pollution research international》2017,24(17):14735-14747
Dendrimer-functionalized multi-walled carbon nanotubes (MWCNT) for heavy metal ion removal from wastewaters were developed. Triazole dendrimers (TD) were built directly onto the carbon nanotube surface by successive click chemistry reactions affording the zero- and first-generation dendrimer-functionalized MWCNT (MWCNT-TD1 and MWCNT-TD2). The Moedritzer-Irani reaction carried out on the amino groups present on the MWCNT-TD2 sample gave the corresponding α-aminophosphonate nanosystem MWCNT-TD2P. Both MWCNT-TD2 and MWCNT-TD2P nanosystems have been characterized by physical, chemical, and morphological analyses. Their chelating abilities towards the toxic metal ions Pb2+, Hg2+, and Ni2+ and the harmless Ca2+ ion have been experimentally evaluated in the two different sets of experiments and at the salt concentrations of 1 mg/mL or 1 μg/mL by inductively coupled plasma mass spectrometry (ICP-MS). The results of these studies pointed out the interesting chelating behavior for the phosphonated nanosystem towards the Hg2+ ion. The complexation mode of the best chelating system MWCNT-TD2P with mercury was investigated through density functional theory (DFT) calculations, suggesting a chelation mechanism involving the two oxygen atoms of the phosphate group. The synthesized dendrimers, supported on the multi-walled carbon nanotubes, have shown the potential to be used for the selective toxic metal ion removal and recovery. 相似文献
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Inputs and distributions of synthetic musk fragrances in an estuarine and coastal environment; a case study 总被引:1,自引:0,他引:1
Nicola R. Sumner Carlos Guitart Gustavo Fuentes 《Environmental pollution (Barking, Essex : 1987)》2010,158(1):215-4648
Synthetic musks are ubiquitous contaminants in the environment. Compartmental distributions (dissolved, suspended particle associated and sedimentary) of the compounds throughout an axial estuarine transect and in coastal waters are reported. High concentrations of Galaxolide® (HHCB) and Tonalide® (AHTN) (987-2098 ng/L and 55-159 ng/L, respectively) were encountered in final effluent samples from sewage treatment plants (STPs) discharging into the Tamar and Plym Estuaries (UK), with lower concentrations of Celestolide® (ADBI) (4-13 ng/L), Phantolide® (AHMI) (6-9 ng/L), musk xylene (MX) (4-7 ng/L) and musk ketone (MK) (18-30 ng/L). Rapid dilution from the outfalls is demonstrated with resulting concentrations of HHCB spanning from 5 to 30 ng/L and those for AHTN from 3 to 15 ng/L. The other musks were generally not detected in the estuarine and coastal waters. The suspended particulate matter (SPM) and sedimentary profiles and compositions (HHCB:AHTN ratios) generally reflect the distribution in the water column with highest concentrations adjacent to sewage outfalls. 相似文献
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Farrag K Senesi N Nigro F Petrozza A Palma A Shaarawi S Brunetti G 《Environmental science and pollution research international》2012,19(8):3636-3644
Greenhouse and field studies were performed to examine the growth responses and possible phytoremediation capacity towards heavy metals of several Brassicaceae (Brassica alba, Brassica carinata, Brassica napus and Brassica nigra) and Poaceae (durum wheat and barley). Soils used featured total concentrations of Cr, Cu, Pb and Zn largely exceeding the maximum levels permitted by the Italian laws. Different organic amendments were tested such as a compost and the plant growth-promoting rhizobacterium Bacillus licheniformis. In the greenhouse experiment, plant length, leaf area index and shoots dry matter were evaluated periodically for the Brassicaceae examined. Whereas plant length, grains production, weight of 1,000 seeds, ear fertility and tiller density were determined under field conditions at the end of the crop cycle for wheat and barley. In general, the species tested appeared to be tolerant to high heavy metal concentrations in soil, and slightly significant differences were found for all parameters considered. A marked growth increase was shown to occur for Brassicaceae cultivated on compost- and bacillus-amended contaminated soils, with respect to non-amended contaminated soils. With some exception, higher growth parameters were measured for wheat and barley plants cropped from contaminated soils in comparison to non-contaminated soils. Further, bacillus amendment enhanced the length of wheat and barley plants in both non-contaminated and contaminated soils, while different effects were observed for the other parameters evaluated. 相似文献
19.
Volpe AM Bandong BB Esser BK Bianchini GM 《Journal of environmental radioactivity》2002,60(3):365-380
Radiocesium, 137Cs, and rare earth elements (REEs) were determined in suspended material and dissolved fractions of waters across the salinity gradient in North San Francisco Bay (estuary). We describe the variation of this conservative isotope tracer with salinity and sediment load. REE data are used to differentiate marine and terrigenous source terrains for suspended material and dissolved fractions. We estimate that about 1-4 x 10(10) Bq of 137Cs migrates annually on suspended material through the North Bay. In addition, 137Cs concentrations were measured in surface waters off Baja California. Combined in situ water density (sigma(t)) and 137Cs data distinguish between California Current and Gulf of California water, and delineate areas of upwelling, where nutrient-rich, deep Pacific Intermediate water, with little or no 137Cs, is brought to the surface off promontories along Baja California. 相似文献
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