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701.
于2017年1、4、7、10月在南京市主城区采集了大气PM2.5样品,用BCR法对PM_(2.5)中重金属进行连续提取,采用电感耦合等离子体-质谱法进行测定,分析重金属在颗粒物中不同形态和分布特征。结果表明,PM_(2.5)中9种重金属质量比排序为:Fe Zn Pb Mn Cu Cr As Ni Cd。Zn、Pb、Cd、Cu、Mn、As主要分布在弱酸提取态; Ni在弱酸提取态、可氧化态和残渣态中分布较均匀,占比26%~37%;而Fe、Cr主要以残渣态存在,分布比例分别为71%和54%。PM_(2.5)中Zn的生物有效性系数 0.8,属生物可利用性元素,表明其在环境中迁移能力最强,其余8种重金属生物有效性系数为0.2~0.8。 相似文献
702.
703.
根据CA文摘的要求,以美国《化学文摘》收录部分环境科学文献为例,对收录前后标题、文摘进行探析。论述科技论文文摘的写作与翻译方法,说明科技文摘写作与翻译中存在的不规范和应注意问题,以便科技文摘更具有科学性。 相似文献
704.
705.
毛细管电泳法直接测定化工废水中邻苯二甲酸二丁酯 总被引:1,自引:1,他引:0
采用胶束毛细管电泳法,在分离水中5种邻苯二甲酸酯的基础上,对化工废水中邻苯二甲酸二丁酯进行了直接测定.以峰面积定量,标准曲线在4 mg/L~50 mg/L线性关系良好,检出限为0.64 mg/L,加标回收率为104%~106%. 相似文献
706.
Manjunatha Kempasiddaiah Vishal Kandathil Ramesh B. Dateer Mahiuddin Baidy Shivaputra A. Patil Siddappa A. Patil 《环境科学学报(英文版)》2021,33(3):189-204
In this paper, highly stable, powerful, and recyclable magnetic nanoparticles tethered N-heterocyclic carbene-palladium(II) ((CH3)3[email protected]3O4) as magnetic nanocatalyst was successfully synthesized from a simplistic multistep synthesis under aerobic conditions through easily available low-cost chemicals. Newly synthesized (CH3)3[email protected]3O4 magnetic nanocatalyst was characterized from various analytical tools and catalytic potential of the (CH3)3[email protected]3O4 magnetic nanocatalyst was studied for the catalytic reduction of toxic 4-nitrophenol (4-NP), hexavalent chromium (Cr(VI)), Methylene Blue (MB) and Methyl Orange (MO) at room temperature in aqueous media. UV-Visible spectroscopy was employed to monitor the reduction reactions. New (CH3)3[email protected]3O4 magnetic nanocatalyst exhibited excellent catalytic activity for the reduction of toxic environmental pollutants. Moreover, (CH3)3[email protected]3O4 magnetic nanocatalyst could be easily and rapidly separated from the reaction mixture with the help of an external magnet and recycled minimum five times in reduction of 4-NP, MB, MO and four times in Cr(VI) without significant loss of catalytic potential and remains stable even after reuse. 相似文献
707.
为确定化工园区突发事故的应急资源需求,提出了一种基于案例推理的化工园区应急资源需求预测方法。该方法主要由三部分组成:(1)基于案例推理的模型构建;(2)化工园区事故的案例描述;(3)基于人工神经网络的案例适应。最后,以石化园区火灾爆炸事故的应急资源需求预测验证该方法的有效性。研究表明,该方法可以实时地对化工园区应急资源需求进行预测,为化工园区的应急资源储备和配置提供支持。 相似文献
708.
Sakan S Grzetić I Dordević D 《Environmental science and pollution research international》2007,14(4):229-236
Introduction In this work, sediments of the River Tisa (Tisza) are studied to assess their environmental pollution levels for some major
heavy metals, as well as to predict the investigated elements’ mobility on the basis of their association type with the substrate.
The Tisa River catchments area is a subbasin of the River Danube. Part of this river, 166 km long, belongs to the Serbian
province of Vojvodina, before it flows into the Danube. It has been chosen for our investigation, because it has been exposed
to intense pollution in the last decades.
Materials and Methods The river sediment samples were collected at 32 locations. The proportions of sand, silt and clay fractions were determined.
The sequential extraction procedure following a modified Tessier method was applied for speciation of the metal forms in the
collected samples. The metal concentrations of Zn, Cd, Pb, Ni, Cu, Cr, Fe and Mn in extracts were determined by atomic absorption
spectroscopy.
Results and Discussion Granulometric analysis showed that some 50% of the Tisa River sediments were silt and clay, while the rest was sand with quartz,
as the main constituent. The average metal content of the surface river sediment samples for every fraction of sequential
extraction was presented and discussed in relation to pH, Eh and metal fractionation. The average metal content from the Tisa
River sediments, obtained as an average of the metal’s concentration released in all five sequential extraction fractions
was compared with: average metal contents of the Tisa River sediments in Hungary, metal content in soils formed on the Tisa
River alluvium of Vojvodina, average metal content in soils of Vojvodina, and average metal content in soils of Hungary. An
assessment of metal pollution levels in Tisa River sediments was made by comparing mean values for obtained results for the
Tisa River sediments with the freshwater sediment’s Quality Guidelines as published by US EPA, Environment Canada and soil
standards for Serbia.
Conclusion According to US EPA and Canadian Quality Guidelines for freshwater sediments, the concentration of heavy metals in Tisa sediments
were: (a) much higher than defined concentrations below which harmful effects on river biota are unlikely to be observed,
(b) below defined concentrations above which harmful effects on river biota are likely to be observed. The concentration levels
of Pb, Ni, Cu and Cr in Tisa River sediments are safe when compared with Serbian MAQ (Maximum Allowed Quantity) standards
for soils, but they are unsafe in the case of Zn and Cd.
Recommendations and Outlook The quality of sediments in the Tisa River was on the border line between potentially polluted and polluted. This line could
very easily be exceeded since the quality of sediments in the Tisa River in Hungary was already worse than in Serbia. These
results indicated the need for further monitoring of heavy metals in that locality. 相似文献
709.
Perrino C Canepari S Cardarelli E Catrambone M Sargolini T 《Environmental monitoring and assessment》2007,128(1-3):133-151
A field study was carried out at six locations in the Lazio region (Central Italy) aimed at characterising atmospheric particulate
matter (PM10 and PM2.5) from the point of view of the chemical composition and grain size distribution of the particles, the mixing properties of
the atmosphere, the frequency and relevance of natural events. The combination of four different analytical techniques (ion
chromatography, X-ray fluorescence and ICP for inorganic components, thermo-optical analysis for carbon compounds) yielded
sound results in terms of characterisation of the air masses. During the first three months of the study (October-December
2004), many pollution events of natural (sea-salt or desert dust episodes) or anthropogenic nature were identified and characterised.
More than 90% of the collected mass was identified by chemical analysis. The central role played by the mixing properties
of the lower atmosphere when pollution events occurred was highlighted. The results show a major impact of primary anthropogenic
pollutants on traffic stations and a homogeneous distribution of secondary pollutants over the regional area. An evaluation
of the sources of PM and an identification of possible reliable tracers were obtained using a chemical fractionation procedure. 相似文献
710.
Hydrogeochemistry and Groundwater Quality Assessment of Lower Part of the Ponnaiyar River Basin, Cuddalore District, South India 总被引:7,自引:0,他引:7
Jeevanandam M Kannan R Srinivasalu S Rammohan V 《Environmental monitoring and assessment》2007,132(1-3):263-274
The Lower Ponnaiyar River Basin forms an important groundwater province in South India constituted by Tertiary formations
dominated by sandstones and overlain by alluvium. The region enjoyed artesian conditions 50 years back but at present frequent
failure of monsoon and over exploitation is threatening the aquifer. Further, extensive agricultural and industrial activities
and urbanization has resulted in the increase in demand and contamination of the aquifer. To identify the sources and quality
of groundwater, water samples from 47 bore wells were collected in an area of 154 km2 and were analysed for major ions and trace metals. The results reveal that the groundwater in many places is contaminated
by higher concentrations of NO3, Cl, PO4 and Fe. Four major hydrochemical facies Ca–Mg–Cl, Na–Cl, Ca–HCO3 and Na–HCO3 were identified using Piper trilinear diagram. Salinity, sodium adsorption ratio, and sodium percentage indicate that most
of the groundwater samples are not suitable for irrigation as well as for domestic purposes and far from drinking water standards.
The most serious pollution threat to groundwater is from nitrate ions, which are associated with sewage and fertilizers application.
The present state of the quality of the lower part of Ponnaiyar River Basin is of great concern and the higher concentration
of toxic metals (Fe and Ni) may entail various health hazards. 相似文献