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131.
Fast screening compositions of PM2.5 by ATR-FTIR: Comparison with results from IC andOC/EC analyzers
Xu Yu Wei Song Qingqing Yu Sheng Li Ming Zhu Yanli Zhang Wei Deng Weiqiang Yang Zhonghui Huang Xinhui Bi Xinming Wang 《环境科学学报(英文版)》2018,30(9):76-88
Chemical speciation of fine particles or PM_(2.5) collected on filters is still a costly and timeconsuming task. In this study, filter-based PM_(2.5) samples were collected during November–December 2013 at four sites in Guangzhou, and the major components were fast screened(~7 min per filter sample) by Attenuated Total Reflectance(ATR)-Fourier Transform Infrared Spectroscopic(FTIR) in comparison with that measured by Organic carbon/Element carbon(OC/EC) analyzer and Ion Chromatography(IC). The concentrations of nitrate, ammonium, sulfate,primary organic carbon(POC) and secondary organic carbon(SOC) measured by OC/EC and IC analyzers were better correlated with their infrared absorption peak heights at 1320 cm~(-1) for nitrate, 1435, 3045 and 3215 cm~(-1) for ammonium, 615 cm~(-1) for sulfate, 690, 760 and 890 cm~(-1) for POC and 1640 and 1660 cm~(-1) for SOC respectively, during polluted days(PM_(2.5) 75 μg/m~3) than during clean days(PM_(2.5)≤ 75 μg/m~3). With the evolution of a haze episode during our field campaign, the concentrations of the major PM_(2.5) components displayed consistent variations with their infrared absorption peak heights, suggesting ATR-FTIR could be a fast and useful technique to characterize filter-based PM_(2.5) compositions particularly during pollution events although cautions should be taken when PM_(2.5) levels are low. Notably, elevated PM_(2.5) mass concentrations occurred with enhanced ratios of [NO_(-3)]/[SO_4~(2-)] and [NH~(+4)]/[SO_4~(2-)], implying that nitrogenous components play vital roles in the PM_(2.5) pollution events in the study region. 相似文献
132.
O. Oenema H.P. Witzke Z. Klimont J.P. Lesschen G.L. Velthof 《Agriculture, ecosystems & environment》2009,133(3-4):280
Following the recognition of the detrimental effects of nitrogen (N) losses from agriculture in the European Union (EU) on human health and environment, series of environmental policy measures have been implemented from the early 1990s onwards. However, these measures have only been partially successful. Clearly, there is lack of integration of available measures and there is lack of enforcement and hierarchy; which measures should be implemented first? We identified and assessed three ‘most promising measures’ to decrease N losses from agriculture, i.e., (i) balanced fertilization, (ii) low-protein animal feeding, and (iii) ammonia (NH3) emissions abatement measures. Environmental-economic assessments were made using scenario analyses and the modeling tools MITERRA-EUROPE and CAPRI.In the baseline scenario (business as usual), N use efficiency (NUE) in crop production increases from 44% in 2000 to 48% in 2020, while total N losses decrease by 10%. Implementation of promising measures increases NUE further to 51–55%, and decreases NH3 emissions (by up to 23%), nitrous oxide (N2O) emissions (by up to 10%) and N leaching losses (by up to 35%). Differences in responsiveness to promising measures varied between and within Member States. Strict implementation of balanced fertilization in nitrate vulnerable zones, as defined in the Nitrates Directive, decreases total farmers’ income in EU-27 by 1.7 billion euros per year. Implementation of all three measures decreases farmers income by 10.8 and total welfare by 17 billion euros per year, without valuing the environmental benefits.The study presented here is one of the first EU-wide integrated assessments of the effects of policy measures on all major N losses from agriculture and their economic costs. Our results show that the most promising measures are effective in enhancing NUE and decreasing NH3 and N2O emissions to the atmosphere and N leaching to groundwater and surface waters, but that income effects are significant. The order of implementation of the measures is important; NH3 emissions abatement measures must be implemented together with balanced N fertilization. 相似文献
133.
The objective of this study was to investigate the soil nitrogen components of four native artificial plantations at the western edge of the Sichuan Basin. Soil samples from two layers (0-20 cm and 20-40 cm) were collected from 4 plantations (Cryptomeria fortunei, Michelia wilsonii, Phoebe zhennan, and Quercus acutissima) during March, June, September, and December 2015 at the western edge of Sichuan Basin, to perform a comparative analysis on seasonal dynamics. Soil ammonium, nitrate, microbial biomass nitrogen, and environmental factors were synchronously monitored. The results showed that soil inorganic nitrogen was mainly the result of nitrate. The components of labile soil nitrogen showed significant seasonal dynamics. Soil ammonium during the growing season (June and September) was higher than that during the non-growing season (March and December), but soil nitrate, microbial biomass nitrogen, and inorganic nitrogen showed the opposite pattern. Labile nitrogen components in the 0-20 cm layer were generally higher than those in the 20-40 cm layer. Labile soil nitrogen was significantly affected by forest type, which was dependent on season and soil layer. In general, there were significant correlations between the soil nitrogen pools and labile soil nitrogen and the environmental factors, including soil temperature, water content, and monthly rainfall. In conclusion, the variation of labile soil nitrogen was influenced more by season than forest type or soil layer. Compared to the biological effects of tree species, the environmental factors had a stronger effect on labile soil nitrogen. © 2018 Science Press. All rights reserved. 相似文献
134.
Om Prakash Stefan J. Green Pooja Singh Puja Jasrotia Joel E. Kostka 《Frontiers of Environmental Science & Engineering》2021,15(2):23
135.
Validation of regression models for nitrate concentrations in the upper groundwater in sandy soils 总被引:1,自引:0,他引:1
For Dutch sandy regions, linear regression models have been developed that predict nitrate concentrations in the upper groundwater on the basis of residual nitrate contents in the soil in autumn. The objective of our study was to validate these regression models for one particular sandy region dominated by dairy farming. No data from this area were used for calibrating the regression models. The model was validated by additional probability sampling. This sample was used to estimate errors in 1) the predicted areal fractions where the EU standard of 50 mg l−1 is exceeded for farms with low N surpluses (ALT) and farms with higher N surpluses (REF); 2) predicted cumulative frequency distributions of nitrate concentration for both groups of farms.Both the errors in the predicted areal fractions as well as the errors in the predicted cumulative frequency distributions indicate that the regression models are invalid for the sandy soils of this study area. 相似文献
136.
Anaerobic biodegradation of 4-alkylphenols in a paddy soil microcosm supplemented with nitrate 总被引:1,自引:0,他引:1
Anaerobic degradation of phenol, p-cresol, 4-n-propylphenol (n-PP), 4-i-propylphenol (i-PP), 4-n-butylphenol (n-BP) and 4-sec-butylphenol (sec-BP) was observed in a paddy soil supplemented with nitrate. We detected the metabolites 4′-hydroxypropiophenone (HPP) from n-PP, 4-i-propenylphenol from i-PP, and 4-(1-butenyl)phenol and 4′-hydroxybutyrophenone (HBP) from n-BP. Compared with the original soils, Betaproteobacteria became predominant in the microcosm during the degradation of phenol and p-cresol whereas no remarkable change was observed in the community degrading propylphenols and butylphenols. The microcosm, however, did not degrade 4-t-butylphenol (t-BP), 4-t-octylphenol (t-OP) and 4-n-octylphenol (n-OP). Paddy soil supplemented with sulfate or iron (III) as electron acceptors did not degrade phenol and 4-alkylphenols with the exception of the degradation of p-cresol in sulfate-reducing conditions. It was demonstrated for the first time that anaerobic microbial degradation of alkylphenols, in a paddy soil supplemented with nitrate as an electron acceptor, occurred via oxidation of the alpha carbon in the alkyl chain. 相似文献
137.
施肥过程中的污染控制 总被引:2,自引:0,他引:2
农业生产造成的自身污染是一个不可忽略的环境问题,化肥施用不当造成植物体内硝酸盐含量增加以及水源的污染,城市活性污沁的农用处理,扩大了农田重金属污染的途径和范围,因此要提介科学种田,合肥施肥,以减轻对农业环境的污染。 相似文献
138.
Nitrate and pesticide contamination of surface and groundwater has become a major problem in intensive farming regions in Europe, with nitrate concentrations reaching values above the standard defined in 2000 by the European Water Framework Directive. In the Seine basin, a major issue is the closure and abandonment of drinking-water wells, which force water managers and drinking-water producers to explore solutions for water resource protection. Organic farming has appeared as a credible alternative to conventional farming, and this study explores the potential of organic farming to reconcile agricultural production and water quality. On the basis of agricultural statistics, survey questionnaires and experimental data, the nitrogen soil surface balance (N-SSB) has been established at the scale of a small 104-km2 catchment (The Orgeval sub-basin), representative of the intensive cash crop farming in the Seine basin. The N-surplus for arable land in specialized organic cash crop systems has been found to be half that of current conventional systems (15 kg N ha−1 yr−1 versus 30 kg N ha−1 yr−1, respectively). The N-yield in organic systems is 21% lower than in conventional systems, but total fertilization (mostly symbiotic N fixation) is also 26% lower. Whereas 2–3 years of forage legume (e.g., alfalfa) as a starter crop of the typical 7- to 10-year diversified rotation builds up N soil fertility and helps prevent weeds without pesticides, the existence of an outlet for this fodder production is a limiting factor for the economic sustainability and the environmental benefits of these farming systems. Therefore, we explored the possibility of a reconnection of livestock and crop farming systems in the Orgeval catchment, a traditional dairy farming and Brie cheese production region. We calculated the N-SSB for this type of a reconnected livestock and cropping system and found a value very close to the specialized organic cash crop system with full utilization of fodder production, leading to profitable animal production, essentially as milk in this farm design. This reconnected system is compared with the estimated situation in 1955 before separation of plant and livestock production. Furthermore, the N-SSB values were converted into infiltrating sub-root concentrations and used as a boundary condition to a biogeochemical model. Organic cropping and organic reconnected livestock cropping systems result in a 50% reduction of surface water nitrate concentrations, a surface water quality 20% better than that reconstructed for 1955, with an overall higher protein production. 相似文献
139.
Preparation of agricultural residue anion exchangers and its nitrate maximum adsorption capacity 总被引:9,自引:0,他引:9
Anion exchangers were prepared from different agricultural residues (AR) after reaction with epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide (EDM method). Agricultural residues anion exchangers (AR-AE) produced by the EDM method were inexpensive and showed almost the same NO3− removal capacities as Amberlite IRA-900. AR-AE produced from AR with higher hemicelluloses, lignin, ash and extractive contents resulted in the lower yields. Sugarcane bagasse with the highest -cellulose contents of 51.2% had the highest yield (225%) and lowest preparation cost. The highest maximum adsorption capacity (Qmax) for nitrate was obtained from rice hull (1.21 mmol g−1) and pine bark natural exchangers (1.06 mmol g−1). No correlation was found between Qmax and -cellulose content in the original AR. AR-AE produced from different AR demonstrated comparable Qmax due to the removal of non-active compounds such as extractives, lignin and hemicelluloses from AR during the preparation process. Similar preparation from pure cellulose and pure alkaline lignin demonstrated that the EDM method could not produce anion exchangers from pure lignin due to its solubilization after the reaction with epichlorohydrin. 相似文献
140.