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541.
采用温和的无模板溶液反应合成了α-Fe2O3/AC复合催化剂,作为光Fenton降解双酚A反应的催化剂。通过XRD、SEM、FTIR、DRS、BET、XPS等方法对催化剂的形貌和理化特性进行了分析。结果表明:该催化剂晶型良好,为介孔材料,能够有效吸收和利用紫外光和可见光;该催化剂具有较高的催化活性,稳定性良好;在初始双酚A质量浓度为30 mg/L、溶液pH为4、H2O2加入量为320 mg/L、反应温度为40 ℃、催化剂加入量为1.33 g/L的条件下,双酚A降解率可达91.4%。 相似文献
542.
随着抗生素抗性污染日益严重,快速评估环境中典型病原菌与条件性致病菌的抗生素抗性水平,对掌握区域环境抗生素抗性污染状况、揭示抗性污染传播规律至关重要。通过以最低抑菌浓度浸入抗生素改进MI、VJ培养基,并结合滤膜法,建立了针对近岸海洋环境中指示性病原微生物大肠杆菌(Escherichia coli,E.coli)与金黄色葡萄球菌(Staphylococcus aureus,S.aureus)的抗生素抗性监测方法。水体和沉积物样品抗生素抗性水平评估实验结果显示,该方法具有较好重现性(水体和沉积物中E.coli和S.aureus抗生素抗性水平的相对标准偏差分别为11%、8%)与准确度(水体和沉积物中E.coli和S.aureus的平均回收率分别为83.5%、68.4%;相对于CLSI药敏试验的偏离度为±0.1)。且与CLSI药敏实验相比,该方法过程简便、耗时短(36 h/84 h),能最大限度节约经济和人员成本提高抗性评价效率。应用该方法评估辽河口与莱州湾环境中2种病原微生物磺胺类抗生素抗性水平,结果显示辽河口水体中E.coli和S.aureus磺胺二甲嘧啶的平均抗性率分别为27.0%、28.4%,沉积物中分别为35.5%、34.6%;莱州湾水体中E.coli和S.aureus磺胺二甲嘧啶的平均抗性率分别为26.0%、14.5%,沉积物中分别为12.0%、32.9%。该方法适用于河口、近岸海洋及入海排污口水体与沉积物样品中E.coli与S.aureus的快速分析及抗生素抗性水平评估。 相似文献
543.
家长吸烟对儿童尿中1-羟基芘的影响 总被引:3,自引:0,他引:3
为了解家长吸烟对小学生尿中1-羟基芘的影响,对4个地区小学生234份尿样中的1-羟基芘及其学校所在地空气中的苯并芘进行了同步采样分析,结果显示,学生尿中的1-羟基芘浓度与所在学校空气中苯并(a)芘的浓度有显著的正相关关系。家长吸烟组学生尿中1-羟基芘浓度均高于家长不吸烟组,但t检验结果差别不显著,根据测定结果的分析,讨论了这种差别的意义。 相似文献
544.
545.
灰色系统理论在湖泊水质预测建模中的应用 总被引:1,自引:0,他引:1
本文将灰色系统理论应用于湖泊水质预测建模研究,提出了湖泊水质预测的建模方法,并建立了某湖化学需氧量(COD)的GM(1,1)预测模型。 相似文献
546.
A method involving high resolution gas chromatography combined with ion trap (HRGC-MS/MS) and negative chemical ionisation
(NCI) was developed for the determination of nitrated or oxygenated polycyclic aromatic hydrocarbons (nitro-PAHs, oxy-PAHs)
and other electrophilic substitutes in soil samples. Efficient clean-up was achieved by a combination of methods for the determination
of PAHs in soil and nitro-PAHs in aerosol using solid phase extraction (SPE) and semipreparative high performance liquid chromatography
(HPLC). In samples of surface soil from the city of Basle (Switzerland), nitro-PAHs (mainly 3-nitrofluoranthene and 1-nitropyrene)
were found in concentrations between 30 and 800 ng/kg dry weight. Oxy-PAHs and parent PAHs revealed 102-104-fold higher levels. Nitro-PAHs which are up to 105 times more mutagenic seem to be less persistent in soil than the parent forms, although their entire mutagenic potential
has to be estimated as being on the same order of magnitude. In urban air particulate matter, the amounts of nitro-PAHs (2–62
pg/m3) were 10–100 times lower than oxyPAHs and parent PAHs which were both found in a similar range. 3-nitrobenzanthrone, a recently
described suspected human carcinogen has not yet been detected. Using multivariate statistical analysis, it was possible to
elucidate similarities or special characteristics of substances in a given matrix reflecting their chemical properties or
specific emission sources. 相似文献
547.
548.
Assessment of New Vehicles Emissions Certification Standards in the Metropolitan Area of Mexico City 总被引:1,自引:0,他引:1
Light duty gasoline vehicles account for most of CO hydrocarbons and NOx emissions
at the Metropolitan Area of Mexico City (MAMC). In order to ameliorate air pollution from the beginning of 2001, Tier 1 emission standards became mandatory for all new model year sold in the country. Car manufacturers in Mexico do not guarantee the performance of their exhaust emissions systems for a given mileage. The purpose of this study was to assess whether the Tier 1 vehicles will stand the certification values for at least 162000 km with the regular fuel available at the MAMC. Mileage accumulation and deterioration show that certified carbon monoxide emissions will stand for the useful life of the vehicles but in the case of non-methane hydrocarbons will be shorter by 40%, and nitrogen oxides emissions above the standard will be reached at one third of the accumulated kilometers. The effect of gasoline sulfur content, on the current in use Tier 1 vehicles of the MAMC and the impact on the emissions inventory in year 2010 showed that 31000 extra tons of NOx could be added to the inventory caused by the failure of the vehicles to control this pollutant at the useful life of vehicles. 相似文献
549.
The transboundary River Nestos in the Balkan Peninsula is a surface water resource shared by Hellas and Bulgaria. The Public Power Corporation of Hellas (DEH) proceeded to the dams' construction of Thesaurus in 1997 and Platanovrissi in 2000, to satisfy the increased needs for power
production and irrigation in the Regions of Eastern Macedonia and Thrace in the Hellenic Territory. DEH following the Ministerial
Agreement of the Hellenic Parliament ‘`KYA 18492/19—09—1996’' funded a series of Research Projects concerned on the monitoring
of the water quantity and quality data of Nestos from the Hellenic-Bulgarian borders to its estuaries in the Thracian sea.
‘`PERSEAS’' Research Group from Aristotle University of Thessaloniki, carried out the research, design, construction, installation,
operation and maintenance of the ‘`R.E.MO.S.’' (Remote Environmental MOnitoring System) networks. Three REMOS networks have
been installed in the areas of (a) the River Nestos deltaic channel, (b) Thesaurus dam-lake in the intramountainous valley
and (c) Potamoi (Despat) and Pagoneri (Nestos) villages close to the borders between Hellas and Bulgaria. They record water
level (H), water and air temperature (T), water conductivity (ECw), Redox potential (RP) and dissolved oxygen (DO) on a 24h
basis, since the beginning of the year 2000. The research carried out in this paper, is focused on the REMOS station in the
final course of Nestos in the deltaic area. The continuous monitoring and the data analysis yield useful results for the quality
and quantity of the hydrologic regime of Nestos after the dams' construction, as well as for the trends detected of the quality
parameters (ECw, RP and DO) and the water level, using the nonparametric Spearman's criterion. The best fitted model of time
trend, for each variable, was chosen. The statistical sample of each one of the quality variables consisted of about 1000
values based on daily measures on a three years monitoring program (1/1/2000—31/12/2002). Further research and analysis for
the other network stations of REMOS should provide useful results for the sustainable management of the transboundary River
Nestos. 相似文献
550.
Deepti Puri R. Karthikeyan M. Babbar‐Sebens 《Journal of the American Water Resources Association》2009,45(4):928-944
Abstract: The two main rivers of southeast Texas: Guadalupe and San Antonio have shown high temporal increase in bacteria concentration during the last decade. The SPAtially Referenced Regression On Watershed (SPARROW) attributes model, developed by the U.S. Geological Survey (USGS), has been applied to predict the fluxes and concentrations of contaminants in unmonitored streams and to identify the sources of these contaminants. This model identifies every reach as a basic network unit to distribute the sources, delivery, and attenuation factors. The model is data intensive and implements nonlinear regression to solve the parsimonious relations for describing various watershed processes. This study explored watershed and hydrological characteristics (land uses, precipitation, human and animal population, point sources, areal hydraulic load and drainage density, etc.) as the probable sources and delivery mechanisms of waterborne pathogens and their indicator (Escherichia coli [E. coli]) in the Guadalupe and San Antonio River basins. The effect of using various statistical indices for model selection on the final model’s ability to explain the various E. coli sources and transport processes was also analyzed. 相似文献