环境样品的热解-溶液吸收预处理及其汞同位素组成的测定

利用多道接收电感耦合等离子体质谱仪(MC-ICP-MS)可实现汞同位素的高精度测定,但对样品预处理的要求很高。目前,液态、固态、气态环境样品的预处理方式不一,存在一定的系统误差。该研究旨在尽可能统一各状态样品的预处理步骤。先将各样品中的不同形态汞富集转化为固体可吸附态,令其吸附在固态载体上,包括:采用金柱富集气体样品中的气态单质汞;以吹扫-金柱捕集法富集液体样品中的溶解气态汞和总汞;用膜过滤法收集大气中的颗粒态汞。最后以管式炉热解定量固态样品,采用高氧化效率的酸性高锰酸钾混合溶液吸收热解产生的Hg~0并氧化为Hg~(2+),保存于溶液中供MC-ICP-MS测定。优化了气体流速、吸收液体积及高锰酸钾浓度等参数,考察了方法空白、回收率及精密度等指标,并将建立的方法应用于大气气态单质汞、大气颗粒态汞、溶解气态汞、雨水总汞和土壤总汞等样品中汞同位素的分析。     

Urban air pollutants and their micro effects on medieval stained glass windows

Levels of urban gaseous and particulate pollutants were investigated in the Cathedral of Cologne, Germany in the framework of the EU-project “VIDRIO”. The purpose of this study was to evaluate the influence of a protective double glazing system on the preservation of ancient stained glass windows by sampling at protected and unprotected windows (indoors, in the interspace and outdoor of the Cathedral). The interspace between the ancient stained glass window and the protective glazing is flushed in the Cathedral by indoor air, hence isolating the historic glass from the outdoor air and exposing it to indoor air on both sides of the glass panels. Concentrations of aggressive gaseous pollutants such as NO₂, SO₂, O₃ and CO₂ as well as elemental concentrations of bulk particles and relative abundances of single particles were surveyed at all sampling locations. Elemental concentrations in bulk particulate matter were found to be significantly lower inside the Cathedral in comparison to the outdoor air. This result is advantageous for the stained glass windows. Single particle analysis of the samples from Cologne showed also soil dust and organic particles as well as sulphates and nitrates, from which the latter two compounds are dangerous for the stained glass windows. On the base of the obtained results, it can be concluded that the protective glazing system in the Cathedral of Cologne can be considered as predominantly advantageous from both the gases' point of view (except for NO₂-candles burning) and from the particles' point of view.     

Contamination Pétrolière de la Microcouche de Surface du Golfe de Fos-sur-mer (Mer Méditerranéee)

Abstract

In a general study on the petroleum contamination of the Fos-sur-mer Gulf (Mediterranean Sea), the surface microlayer was sampled. We present here the first results reported up to date in this area, based on a sampling carried out with a rotating PVC drum at 3 stations in May 1985.

Very high hydrocarbons concentrations were sometimes observed in the surface film, which appears more heterogeneous than the underlaying water column (0.5-2m). Water samples were filtered through fiberglass filters (0.5-1 μm). Both dissolved and particulate phases were separately extracted and analysed, providing evidence that suspended particles are the major vector for the accumulation and the transport of petroleum pollutants in these neritic waters.

The petroleum origin of “total hydrocarbons” fractions is confirmed by GC and HPLC which reveal characteristic features for n-alkanes and polynuclear aromatic hydrocarbons. HPLC analysis of polar (non-hydrocarbons) fractions could indicate their formation from petroleum components. Furthermore, the comparison with the underlying waters shows that volatilization and biodegradation are the major processes affecting hydrocarbons distribution in these superficial waters.

Biological data (bacteria, chlorophylls, ATP and energetic charge) were simultaneously measured and indicated an important inhibition of phyto- and bacterio- neuston regarding to the planktonic organisms.     

Validating the correlation of traffic-associated hydrocarbon and nitrogen dioxide with distance from a trunk road within a rural environment in UK

This study monitored traffic-associated air pollutants at four sampling sites within the A49 trunk road. Measurements of the gaseous air pollutants were carried out at various distances (roadside, 50 m, and 100 m) from the A49 trunk road using short term tubes at breathing heights. Data was collected over a 23-month period (June 2008-April 2010). Statistical analyses of hydrocarbon (HC) and nitrogen dioxide (NO₂) show positive r² and p-values, and suggest seasonal, intra- and inter-site variations in a distance-decay relationship. Higher mean concentrations were obtained within the winter season and near the roadside with a gradual decline with distance from the emission source. However, at some locations with increased vehicular activities, this relationship was altered. Elevated mean concentrations were observed within 50 m at Craven Arms (CA 50) and Strefford Road (SR 50); suggesting the influence of traffic on the concentration levels of the contaminants.     

The determination of hydrogen chloride in ambient air with diffusion/denuder tubes

A manual method for the determination of hydrogen chloride in air, based on diffusion/denuder tube separation from particulate chloride aerosol is described. When air is drawn through a tube coated with a selective absorbent (sodium fluoride), separation is achieved because gaseous hydrogen chloride diffuses much more rapidly to the tube walls than particulate chloride aerosol, which passes through virtually unabsorbed. After the sampling period (the length of which depends on the concentration of gaseous hydrogen chloride expected), the sorbed hydrogen chloride is washed from the tube and measured with a highly sensitive chloride ion-selective electrode with a mercury (I) chloride membrane. The method is examined theoretically and experimentally. The experimentally derived absorption efficiencies of the diffusion/denuder tubes were > 90% and the standard deviation of the method was 0.023 μg m^?3 for hydrogen chloride concentrations of 0.16–0.55 μg m^?3. Interference from particulate chloride salts was negligible; this was confirmed by tests with artificially generated aerosol particles from an aerosol generator. The diffusion/denuder tubes have high capacity; level as high as 330 μg m^?3 hydrogen chloride can be sampled for 60 min without affecting performance. A detection limit of (50/t) μg m^?3 can be achieved, where t is the sampling rime (min); e.g., 1μg m^?3 hydrogen chloride can be detected with a sampling period of 50 min.     

Simultaneous analyses of gaseeous and particulate sulfur in the atmosphere by X-ray fluorescence spectrometry--results of observation and discussion-- (author's transl)

Concentrations of gaseous and particulate sulfur in the atmosphere were simultaneously measured for 24 hours at a time interval of one hour by the use of the method described in the previous report (this journal, 24, 312 (1975)). Such measurements were made sixteen times in the period from April to September, 1975. As the result of the measurements, it was found that the method used can be applied to practical observation with sufficient reliability. The concentration of gaseous sulfur showed always a larger variation coefficient than that of particulate sulfur. Both the concentrations of gaseous and particulate sulfur were found strongly dependent on the wind direction and velocity and other meteorological conditions. After hot and fine days continued, the concentration of particulate sulfur rose considerably reaching 20 microgramS/m3.     

Determination of Atmospheric Polycyclic Aromatic Hydrocarbons Using Accelerated Solvent Extraction

Abstract

An accelerated solvent extraction (ASE) method has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) present in both atmospheric particulate and gaseous phases in this study. Extraction parameters such as the combination of solvents, extraction temperature, and static extraction time were investigated and optimized. Effective extraction was achieved using a 3:1 mixture of n-hexane and acetone as extraction solvents at 100°C in 30 min for all the compounds studied. The optimized extraction method was compared with conventional extraction methods and validated using National Institute of Standards and Technology (NIST)–certified standard reference material (SRM) 1649a. The recoveries obtained for certified 12 PAHs were in the range of 82–126% with relative standard deviation (RSD) between 6 and 28%. The validated ASE technique was used followed by gas chromatography–mass spectrometry (GC-MS) for the determination of PAHs distributed between gaseous and particulate phases in the atmosphere of Singapore. Total average concentrations of PAHs in air samples were 33.54 ± 19.32 ng m^?3, with 4.72 ± 2.80 ng m^?3 in particulate phase and 28.82 ± 16.92 ng m^?3 in gaseous phase, respectively. The results obtained from this study are compared to those reported from other areas of the world.     

Measurements of atmospheric mercury with high time resolution: Recent applications in environmental research and monitoring

In the past five years automated high time-resolution measurements of mercury species in ambient air have promoted remarkable progress in the understanding of the spatial distribution, short-term variability, and fate of this priority pollutant in the lower troposphere. Examples show the wide range of possible applications of these techniques in environmental research and monitoring. Presented applications of measurement methods for total gaseous mercury (TGM) include long-term monitoring of atmospheric mercury at a coastal station, simultaneous measurements during a south-to-north transect measurement campaign covering a distance of approximately 800 km, the operation on board of a research aircraft, and the quantification of mercury emissions from naturally enriched surface soils. First results obtained with a new method for the determination of reactive gaseous mercury (RGM) are presented. Typical background concentrations of TGM are between 1.5 and 2 ng m(-3) in the lower troposphere. Concentrations of RGM have been determined at a rural site in Germany between 2 and 35 pg m(-3). Flux measurements over naturally enriched surface soils in the Western U.S.A. have revealed emission fluxes of up to 200 ng Hg m(-1) h(-1) under dry conditions.     

Temporal variation of atmospheric polycyclic aromatic hydrocarbon concentrations in PM10 from the Kathmandu Valley and their gas-particle concentrations in winter

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM) with a diameter <10 µm (PM₁₀, 50% cut off) were investigated in the Kathmandu Valley, Nepal, during 2003. In order to understand the dynamics of atmospheric PAHs in winter, the PAH concentrations in total PM and in the gaseous phase were investigated in the valley in December 2005. Total of 45 PAH compounds (∑45PAHs) were analysed by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). In 2003, the ∑45PAH concentrations in PM₁₀ ranged between 4.3 and 89 ng m^?3 (annual average; 27 ± 24 ng m^?3). The average concentrations of ∑45PAHs in December 2005 were 210 ± 33 ng m^?3 in total PM and 430 ± 90 ng m^?3 in the gaseous phase. The ∑45PAH concentration in PM accounted for more than 30% of the sum of their particulate and gaseous forms. Phenanthrene (Ph) was the most predominant compound in the gaseous phase, whereas four- to seven-ring PAHs were predominant in total PM. The highest values of ∑45PAHs occurred in the winter and spring. Estimates of emission sources based on diagnostic molecular ratios showed that atmospheric PAHs in the Kathmandu Valley mainly originated from the exhaust gas of diesel engine. In the winter and spring, PAH pollution would be accelerated by the operations of brick kilns and the frequent formation of an atmospherically stable layer in the valley.     

Silver based mercury film electrode: Part II. The influence of aging of electrode on the electrode processes of various metal ions

The cyclic voltammetric behaviour of 8 metal ions at solid silver amalgam electrodes prepared by aging of a thin silver based mercury film electrode (SBMFE) and by deposition of silver and mercury on platinum were investigated. It was established that such electrodes behave in relation to some metals (Pb, Bi, Sn) similarly as silver electrodes i.e. the cyclic curves obtained with these electrodes at concentration 10^?3M range show a prepeak-postpeak system corresponding to deposition and dissolution of the monolayer of deposit. On the other hand under the same conditions no prepeaks were observed for cadmium, zinc and thallium. In all cases investigated the heights of anodic stripping peaks were lower on curves obtained with aged SBMFE than on those obtained with fresh SBMFE having a mercury layer 1 μm thick.     

大气复合污染及灰霾形成中非均相化学过程的作用

城市和区域大气复合污染的特征为污染源排放的一次污染物通过大气中的化学反应生成高浓度的氧化剂(臭氧等)及细颗粒物等二次污染物,它们在静稳天气下积累,导致低能见度的灰霾现象并严重影响人体健康和气候.大气复合污染中同时存在高浓度的一次排放和二次转化的气态及颗粒污染物,这为细颗粒表面非均相反应提供了充足的反应物;而气态污染物在细颗粒表面的非均相反应可改变大气氧化性及颗粒物的化学组分、物化性质和光学性质,从而可能对大气复合污染和灰霾的形成起到促进的作用.利用漫反射红外傅里叶变换光谱和单颗粒显微拉曼原位在线技术,我们对大气气态污染物NO2、SO2、O3、甲醛在CaCO3、高岭石、蒙脱石、NaCl、海盐、Al2O3和TiO2等大气主要颗粒物表面的反应进行了系统的反应动力学和机制研究,我们发现反应主要产物为硫酸盐、硝酸盐或甲酸盐,它们可极大改变颗粒物吸湿性和消光性质.通过分析这些非均相反应的动力学过程,我们识别出NO2-颗粒物-H2O、SO2-颗粒物-O3、有机物/SO2-颗粒物-光照等三元反应体系的协同作用机制,这些协同机制对于阐明大气复合污染及灰霾形成的反馈机制和非线性过程提供了实验证据和理论依据.     

An Electrochemical Flow Cell For The Detection Of Metal Complexes

Abstract

An electrochemical flow cell has been developed using reticulated vitreous carbon (RVC) coated with a thin film of mercury. The flow cell and electrode components are inexpensive and easily constructed. Reproducible results have been obtained for concentrations as low as 100 ppb. Peak currents were dependent on flow rate, electrode size, and mercury deposition time. Oxygen interference was reduced by nitrogen purging to enable analysis of sub-ppm metal concentrations. The cell was tested as a detector for metal complexes eluated from a modified gel permeation chromatographic column.     

Chemical characterization of selected metals by X-ray fluorescence method in particulate matter collected in the area of Krakow, Poland

This study presents the results of year long (2007–2008) particulate matter collecting campaigns. The three particle size fractions of particulate matter were collected in Krakow, Poland. Fine fraction consists of particles of a diameter below 2.5 µm, medium is between 2.5 and 8 µm and coarse fraction contains particles above 8 µm. Elemental concentrations were evaluated for each sample. Following elements were measured by EDXRF method: K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Br, and Pb. During each sampling campaign meteorological parameters such as temperature, wind speed, wind direction, humidity were taken from the same place. The highest values of mass particulate matter showed results from January 2008 and April 2008. These were about 14 µg/m³ for fine fraction, 8 µg/m³ for medium and 16 µg/m³ for coarse fraction. The lowest values were observed in May 2007, they were 4, 6, 6 µg/m³, respectively. During the winter season the wind speed was low and particulate matter remained in the air in high concentrations. In May 2007 the speed of wind was higher, reaching 2–3 m/s. PM was blown away from the city from the direction of N–W. Measured concentrations of elements were low, they were below permissible values specified by EU. The coarse fraction concentrations of Ca, Mn, and Fe were higher and characterized by the same trend. These samples were collected when the wind speed was low and its direction was from south-east. As concentrations of Cr, Cu, and Zn were low, these elements did not come from the south-east direction of Krakow. Concentration of Br correlates to the concentration of Pb. It suggests that they came from the same source (vehicles fuels burning).     

Size distribution and characteristics of chemical components in ambient particulate matter.

Ambient particulate matter and gas in Kyoto were investigated by gravimetric analysis, X-ray fluorescence spectrometry, and ion chromatography in order to clarify their behavior and origin. The size distribution and characteristics of the chemical components in ambient particulates collected on PTFE membrane filters using an Andersen air sampler were examined from August 2001 to April 2004. A four-stage filter pack method was used to sample the atmosphere for the determination of gas (SO2, HNO3, HCl, NH3) and particulate matter (SO42, NO3, Cl-, Na+, K+, Ca2+, Mg2+, NH4+) concentrations from October 2002 to April 2004. The concentration of SPM mass was in the range of 6.7 - 80.2 microg/m3. The size distributions of SPM mass were bimodal, peaking at around 0.65 - 1.1 and 3.3 - 4.7 microm, and 40 - 85% of SPM mass was fine particles (< 2.1 microm). Na, Mg, Al, Si, Ca, Cl, and Fe were mainly present in coarse particles (2.1 to 11.0 microm), while S was present in fine particles. The concentrations of Al, Si, Ca, Mg, and Fe in fine particles increased from March to April in 2002, and those in coarse particulates increased in November 2002 and from March to April in 2004. This may be the effect of the continental yellow sand "Kosa." The differences in the size distributions of Al, Si, Ca, Mg, and Fe in particles may depend on differences in their place of occurrence and course of transport from China to Japan. The concentration of HCl gas was higher than that of particulate chloride ion in summer. Nitric acid gas existed at higher concentrations in summer, but fine particulate nitrate ion was observed in winter. The gaseous-to-fine aerosol nitrate fraction became higher at warmer temperatures. Coarse sulfate was below 10%, and SO2 gas and fine particulate sulfate were above 90%.     

Source Apportionment for the Zinc—Containing Component of Air Particulate Matter using Automated Electron Probe Micro Analysis of Individual Particles

Abstract

A methodology is described for the apportionment of zinc-containing particulate matter sampled in the vicinity of a zinc smelter to their corresponding sources in the factory. Bulk samples of particulate matter from six potential emission sources were analysed by automated electron probe microanalysis (EPMA) in order to characterize the individual particles. Based on a data set of relative peak intensities and with the aid of a binary clustering method, the most important particle classes were identified. They were used as a basis for the development of a set of disjunct identification rules (decision rules), which were able to describe the classes in a unique manner. Applying these rules upon ambient particulate data enabled the estimation of relative contributions of different types of zinc-containing particles. Evidence was found that a large number of particles was modified by a soil component or by gas phase reactions.     

Mercury in atmospheric aerosols: A preliminary case study for the city of Krakow,Poland

The level of contamination by mercury associated with airborne particulate matter in Krakow was determined. Samples of PM10 were collected on quartz filters using low-volume samplers. The total particulate mercury (TPM) concentrations in collected samples were determined by mercury analyser MA-3000 (Nippon Instruments Corporation). The reported results include also data on the carbonaceous aerosol and inorganic ions concentrations during the reported sampling campaign. The average concentration of the Total Particulate Mercury (TPM) in Krakow (Poland) was 0.22 ng·m⁻³ (during the period from 22 February to 2 March) and 0.49 ng·m⁻³ (on 3 March). A marked correlation between TPM and elemental carbon (EC) as well as with Cl^– was found. No significant association of the TPM with NO₃^– and SO₄^2– could be shown. The dry deposition flux of mercury was calculated as an average over the sampling period and was 47.3 ng·m⁻²·d⁻¹.     

Application of an Electrostatic Precipitator for Instrumental Sampling of Sulfuric Acid

Abstract

A means of separating gaseous sulfuric acid from flue gas particles has been evaluated. Previous attempts to achieve this separation by filtration resulted in retention of the acid by the particulate buildup on the filter surface. By conducting a laboratory study of a prototype electrostatic precipitator, followed by actual flue gas sampling, it was found that the precipitator may eliminate the need for a filter without affecting the measurement results. It was also found that the precipitator could be used prior to a prototype acid monitor for the successful continual monitoring of H₂S0₄ in combustion gases.     

410t/h煤粉锅炉的汞排放及其NID系统除汞特性研究

对配备有NID系统的410t/h燃煤电站锅炉的煤、底渣、飞灰进行取样,测定了样品中汞的含量。采用Ontario Hydro方法测定了NID前和ESP后烟气中汞的形态。实验结果表明,汞主要以飞灰形式排放,占总汞量的90%,烟气汞占10%。NID前和ESP后的烟气中,汞的浓度分别为21.3μg/m3~22.4μg/m3和1.93μg/m3~3.67μg/m3,说明该NID系统对烟气中汞具有相当高的脱除效率,达到83.6%~90.9%。对汞的化学形态研究表明,NID前烟气汞主要以Hg2+形式存在,占气态汞量的67%;ESP后烟气中Hg2+占气态汞量的71.8%~85.1%,Hg0的含量为零,说明烟气中Hg0在NID系统中经历一系列的氧化还原反应后,被氧化成Hg2+并吸附脱除。     

Tensammetry with accumulation on the hanging mercury drop electrode: Part 1. The influence of preconcentration potential on the accumulation of poly(ehtylene glycols) with various molecular weights

The preconcentration of poly(ethylene glycols) (PEG) with various molecular weights on the hanging mercury drop electrode (HMDE) from a stirred solution was studied for the tensammetric determination of trace concentrations of these polymers. Preconcentration was significant in the case of PEGs having m.w. > 1000. The influence of the preconcentration potential on the cathodic tensammetric peak heights was studied in detail for PEG 1500, PEG 4000, PEG 6000, PEG 9000 and PEG 20 000. The concentration of the PEG affects this dependence. With a preconcentration potential of ?1.76 V vs. SCE applied for 10 min, the calibration graphs of these PEGs were linear in the concentration range 0.01–0.10 mg 1^?1.     

Determination of extractable organohalogens in the atmosphere by instrumental neutron activation analysis

Summary Air samples were collected at a downtown site in Beijing from January to July 2004 and analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction method for the concentrations and distributions of extractable organohalogens (EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and organoiodinated compounds (EOI). The concentrations of EOX were increasing in the order of EOCl >> EOBr ~ EOI in both gaseous and particulate phase. EOCl accounted for 75.8-100% and 83.7-100% of EOX in particulate and gaseous phase, respectively, suggesting that EOCl was the major component of the organohalogens in the atmosphere. In the plots of the logarithm of the EOX concentrations versus the reciprocal temperature, their linear relations were observed for EOCl (R = -0.9), for EOBr (R = -0.6) and EOI (R = -0.7) in gaseous phase, which indicated that the concentrations of EOCl, EOBr and EOI in gaseous phase exhibited a strong temperature dependence, i.e., their concentrations increased with increasing of temperature.