Determination of water-soluble and insoluble (dilute-HCl-extractable) fractions of Cd,Pb and Cu in Antarctic aerosol by square wave anodic stripping voltammetry: distribution and summer seasonal evolution at Terra Nova Bay (Victoria Land)

Eight PM10 aerosol samples were collected in the vicinity of the “Mario Zucchelli” Italian Antarctic Station (formerly Terra Nova Bay Station) during the 2000–2001 austral summer using a high-volume sampler and precleaned cellulose filters. The aerosol mass was determined by differential weighing of filters carried out in a clean chemistry laboratory under controlled temperature and humidity. A two-step sequential extraction procedure was used to separate the water-soluble and the insoluble (dilute-HCl-extractable) fractions. Cd, Pb and Cu were determined in the two fractions using an ultrasensitive square wave anodic stripping voltammetric (SWASV) procedure set up for and applied to aerosol samples for the first time. Total extractable metals showed maxima at midsummer for Cd and Pb and a less clear trend for Cu. In particular, particulate metal concentrations ranged as follows: Cd 0.84–9.2 μg g⁻¹ (average 4.7 μg g⁻¹), Pb 13.2–81 μg g⁻¹ (average 33 μg g⁻¹), Cu 126–628 μg g⁻¹ (average 378 μg g⁻¹). In terms of atmospheric concentration, the values were: Cd 0.55–6.3 pg m⁻³ (average 3.4 pg m⁻³), Pb 8.7–48 pg m⁻³ (average 24 pg m⁻³), Cu 75–365 pg m⁻³ (average 266 pg m⁻³). At the beginning of the season the three metals appear widely distributed in the insoluble (HCl-extractable) fraction (higher proportions for Cd and Pb, 90–100%, and lower for Cu, 70–90%) with maxima in the second half of December. The soluble fraction then increases, and at the end of the season Cd and Pb are approximately equidistributed between the two fractions, while for Cu the soluble fraction reaches its maximum level of 36%. Practically negligible contributions are estimated for crustal and sea-spray sources. Low but significant volcanic contributions are estimated for Cd and Pb (∼10% and ∼5%, respectively), while there is an evident although not quantified marine biogenic source, at least for Cd. The estimated natural contributions (possibly including the marine biogenic source) cannot account for the high fractions of the metal contents, particularly for Pb and Cu, and this suggests that pollution from long-range transport is the dominant source. Figure Aerosol sampling in Antarctica     

Evolution of anthropogenic aerosols in the coastal town of Salina Cruz,Mexico: part III size-segregated elemental composition analysed by total-reflection X-ray fluorescence spectrometry

Heavy metals in various size modes of the atmospheric aerosol are a concern for human health. Their and other elements’ concentrations are indicative for anthropogenic and natural aerosol sources. Si, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Hg, and Pb were determined as a complementary contribution to a study on aerosol cycling during the wet season, June 2004, in a humid, subtropical climate, i.e. in the city of Salina Cruz, situated on the Pacific coast of the Isthmus of Tehuantepec (16.2°N, 95.2°W), Mexico. For mass (gravimetry) and elemental analyses, particles were collected by a Berner low-pressure round nozzle cascade impactor using four stages corresponding to 0.1–0.25, 0.25–1.0, 1.0–4.0, and 4–16?µm of aerodynamic particle size. The impaction plates were modified such that approx. 1/6 consisted of a plastic support (Persplex®) for total reflection X-ray fluorescence spectrometry (TXRF). The elements’ total content was determined by TXRF without any further sample pretreatment. Limits of quantification (LOQ) for elemental content in individual impactor stages corresponded to 25–60?ng?m^?3 for Si; 0.8–4?ng?m^?3 for Cl, K, Ca, Ti, and V; 3–20?pg?m^?3 for Cr, Mn, Fe, Cu, Ni, and Zn; and 7–50?pg?m^?3 for As, Se, Br, Rb, Sr, Hg, and Pb. In some samples, however, high blank values for the supports gave an LOQ?=?6–19?ng?m^?3 for Cl; 3--7?ng?m^?3 for Ca; 3–7?ng?m^?3 for Fe, Ni, Cu, and Zn; and 60–70?ng?m^?3 for Pb. The influence of local natural, industrial, and vehicle traffic sources for heavy-metal mobilization was obvious. Heavy-metal abundances did not coincide with regionally distributed pollutants. V and Ni were found at particularly elevated levels advected with the sea breeze, which points to ships as sources. Br and Pb were found at particularly low levels. The concentrations of Br, Rb, Sr, and Pb were found below LOQ at least in some, As, Co, Se, and Hg in all of the samples. The elements’ characteristic differences in mass size distributions were obvious despite the coarse size resolution. During the cycling of air masses from land to sea and back again, enrichment of super-micrometre particles in the near ground aerosol was observed under dry weather conditions. Rain preferentially removed the large particles with which heavy metals have been associated.     

Determination of suspended particulates matter of major significance to human health using nuclear techniques in kenya

Energy dispersive X-ray fluorescence (EDXRF) analysis of aerosol samples in Nairobi is presented. Results show that elemental concentrations are of the order of 10^–4 to 10^–6 g/m³ for most elements analyzed. The total suspended particulate (TSP) matter was between 30–80 g/m³ for the entire sampling period between December 1993 to October 1994. Levels of lead (Pb) are below WHO guidelines. However, the obtained bromine (Br) to Pb ratio: 0.3–0.51, shows the origin of Pb to be from vehicular emissions. This ratio was particularly high during the months of April to July 1994 which were also found to be very active in terms of weather parameters.     

210Pb and 210Po radionuclides in the urban air of Lodz, Poland

The concentration of two important radionuclides: ²¹⁰Pb and its decay product ²¹⁰Po in the urban air in the center of the Polish city of Lodz were measured during the winter and spring seasons of 2008–2009. Urban airborne particulate matter was collected using two methods: an Anderson 9-stage impactor, and a high-volume aerosol sampler type ASS500 working in the frames of the aerosol sampling network in Poland, established for radionuclide monitoring. Average concentrations for 10 months sampling period for ²¹⁰Pb and ²¹⁰Po were 0.556 and 0.067 mBq/m³, respectively. However remarkable fluctuations due to meteorological condition were observed: from 0.010 to 0.431 mBq/m³ for ²¹⁰Po and from 0.167 to 1.847 mBq/m³ for ²¹⁰Pb. The highest concentrations, almost 60% of the total activities, of both radionuclides were found in the first two fine aerosol fractions with particle diameters below 0.36 μm. The aerosol residence times calculated from the ²¹⁰Po/²¹⁰Pb ratio ranged from 7 to 120 days.     

Seasonal variation of natural radionuclides and some elements in plant leaves

Leaf and aerosol samples were monthly collected in Mt. Sefuri (Fukuoka Prefecture). Radioactivities of ⁷Be, ²¹⁰Pb and ⁴⁰K were determined with gamma-ray spectrometry. The concentrations of some elements in the leaf samples were determined by neutron activation analysis. Similar seasonal variation of ⁷Be and ²¹⁰Pb was observed between leaf and aerosol samples, high in spring and winter and low in summer. Correlation factors for trace elements contained in the leaf show large variations. This indicates that the contribution of two sources (atmospheric deposition and uptake from soil) is very variable.     

A neutron activation analysis method for the determination of Be,Li, B,F, and Pb

A neutron activation analysis procedure that utilizes reactor pulsing, rapid sample transfer and a Cerenkov counter for the determination of Be, Li, B, and F via very short-lived radioisotopic indicators is shown to give analytical sensitivities for these elements of 15μg, 0.0008μg, 1.1μg, and 0.83μg, respectively. Use of a NaI(Tl) counter coupled to the same system enables the detection of 0.4μg of Pb via 0.8 second^207mPb.     

Impact of phase out of leaded gasoline on the air quality in Budapest

As part of an air pollution study in Budapest, size-fractionated aerosol samples were collected by stacked filter units and cascade impactors, and some criteria pollutants and meteorological parameters were recorded in 1996, 1998 and 1999. The samplings were performed at three urban locations including an urban background site, a downtown site, and a tunnel. Elemental composition of the aerosol samples was measured by instrumental neutron activation analysis and/or particle-induced X-ray emission spectrometry; and black carbon (BC) was determined by a light reflectance technique. Since leaded gasoline was completely phased out in Hungary on 1 April 1999, the atmospheric concentrations of some typical transportation-related air pollutants (i.e. Pb, Br, BC and CO) were used for overviewing the actual impact of the phase out on the air quality and on the aerosol characteristics. For the background site, mean concentration of Pb and Br was not changed significantly. In the downtown site, the phase out resulted in a concentration decrease by a factor of 3–4 for Pb and Br. For the tunnel, concentrations of Pb and Br were decreased by a factor up to 9 and 28, respectively. Correlation between the pollutants, their crustal enrichment factors, and average elemental mass size distributions are also presented and discussed.     

Design of aerosol sampler to remove radon and thoron progeny interference from aerosol samples for nuclear explosion monitoring

A Nuclear Explosion Monitoring Inertial Impactor (NEMII) system was developed to physically separate naturally occurring radionuclides from those produced in nuclear weapons explosions. Studies show that aerosols containing natural activity have an aerodynamic diameter in the range of 0.1–1.0 μm. It has been established that atmospheric nuclear explosions produce radioactive aerosols with aerodynamic diameters <0.1 μm and surface explosion produce a bimodal distribution of radioactive particles with aerodynamic diameters both >1.0 μm and <0.1 μm. A high volume (66 m³ h⁻¹) impactor was designed to separate the particles into three size distributions: aerosols with aerodynamic diameters >1.0 μm, between 0.1 and 1.0 μm, and smaller than 0.1 μm. Calculations based on previous work for high-volume impactors were completed to obtain the impactor geometry that yields the desired cutoff values. The components of the aerosol impactor were manufactured or obtained and then assembled. In addition, a submicrometer aerosol generation system was assembled to benchmark the NEMII system against a commercial Micro-Orifice Uniform-Deposit Impactor (MOUDI). The MOUDI was also used to verify the naturally occurring radioactivity distribution using ²¹²Pb gamma spectra.     

A particle-size specific elemental mass balance for the apportionment of ambient aerosol

Photon and thermal neutron activation analysis were used to determine the concentrations of up to thirty elements in aerosol samples collected by cascade impactor in Toronto, Canada during the period July to December of 1985. Examination of the particle-size distributions thus obtained led to the development of a new receptor model. A size-specific elemental mass balance (SSEMB) was used to apportion the mean ambient Pb aerosol concentration amongst four contributing sources as follows: secondary lead refinery emissions (46%), refuse incineration (28%), automotive exhaust (25%) and re-entrained soil and dust (<1%). The predicted concentrations of Al, As, Br, Na, Pb, Sb, and Zn agreed with observed concentrations to within a factor of two for most elements in most particle size fractions.     

Elemental characterisation of strawberry grown in Islamabad by <Emphasis Type="Italic">k</Emphasis><Subscript>0</Subscript>-instrumental neutron activation analysis and atomic absorption spectrophotometry and its dietary assessment

Mineral contents of strawberry, collected from different farms of Islamabad were analysed by semi-absolute k ₀-instrumental neutron activation analysis and atomic absorption spectrophotometry. The samples were irradiated at two research reactors located in Pakistan Institute of Nuclear Science & Technology (PINSTECH), Islamabad. The analytical methodologies were validated by analysing reference materials, IAEA-336 (lichen) and IAEA-V-10 (hay powder). In all the samples, a total of 26 elements were quantified, among them 16 elements (Ca, Cd, Cl, Co, Cr, Cs, Fe, K, Mg, Mn, Na, Pb, Ru, Sc, Sr and Zn) were found in all the samples. The determined elemental concentrations in strawberry were compared with the reported values from other countries. In comparison with the mineral contents of other fruits, strawberry stands best source of Mn and the second most important source of K after banana. Intake of trace metals through this source was calculated and it was found that strawberry provides Mn (1.95–3.68 mg/kg), Cr (19.2–46.3 × 10⁻³ mg/kg), Fe (3.45–8.72 mg/kg), K (1,520–1,670 mg/kg) and Mg (100–220 mg/kg), which forms 26, 19, 14, 7 and 7% of the recommended dietary allowances for the respective metals. The daily intake of Cd and Pb were compared with the provisional tolerable weekly intake defined by FAO/WHO.     

A contribution to the characterization of the aerosol sources in São Paulo

Fine and coarse particles in suspension in the atmosphere were collected on two Teflon filters with a dichotomous sampler. The concentration of Al, Br, Ca, Ce, Cl, Co, Cr, Fe, K, La, Mn, Na, P, Pb,, S, Sb, Sc, Se, Si, Sm, Th, V and Zn was determined by ED-XRF and INAA. The elemental concentration was analyzed by means of linear correlation coefficients, enrichment factors and principal factors analysis in order to identify the aerosol sources. The main sources of the aerosol particles were the marine ones, resuspended soil, fuel-oil combustion, phosphatic rocks, refuse incineration and residual high-temperature processes.     

Seasonal variation and activity size distribution of <Superscript>7</Superscript>Be in ambient air

The seasonal variation of the ⁷Be activities in air and the size distribution of the ⁷Be aerosols were studied by using a continuous air sampler and a five stage cascade impactor. The mean monthly activity level of ⁷Be at the Korea Atomic Energy Research Institute (KAERI) site varied from 0.5 to 4.8 Bq·m⁻³ and revealed a seasonal variation, in which the ⁷Be activity levels were high in winter and low in summer. The mass size distribution showed a bi-modal distribution with a higher peak around 0.49 μm and a smaller peak between 3 μm and 7.2 μm. The activity median aerodynamic diameter (AMAD) decreased with increasing ambient ⁷Be concentrations. The mean residence times by using a mean growth rate of 0.004 μm·h⁻¹ were estimated to be 2.5–6.4 days. The AMAD has an increasing tendency with higher relative humidity. It seemed that the high humidity condition facilitated the growth of the aerosol, resulting in increased deposition rates of the aerosols and the low ⁷Be content in the surface air. The AMAD of the ⁷Be aerosols increased with an increasing temperature, but the temperature dependency of AMAD should be explained with geological and meteorological conditions.     

The determination of nickel in air dust by neutron activation analysis

The determination of nickel in atmospheric aerosols, collected on filter paper, is performed by thermal neutron activation analysis using the⁶⁵Ni (T=2.56 h) isotope. Liquid-liquid extraction and anion-exchange are applied in the chemical separation. The absolute sensitivity of the method is ≌0.02 μg Ni. The relative sensitivity is 0.005 μg Ni/m³ if an air sample of about 1000 m³ is used.     

Mosses as Indicators of Atmospheric Pollution of Trace Metals (Cd, Cu, Pb, Mn and Zn) in the Vicinity of Coal-Fired Brick Kilns in North-Eastern Suburbs of Islamabad, Pakistan

Determination of toxic elements Cd, Pb and other heavy metals has been carried out for Rawalpindi - Islamabad region using the moss monitoring technique. The carpet moss samples (Hypnum Cupressiforme) were collected over an area of 196 km² around lignite/coal-fired brick kilns for regular periods of time during 1997–1999. The elements were extracted into solution with multiacid digestion and then analyzed by atomic absorption spectrometry. The metal contents in moss samples from sites adjacent to coal-fired brick kilns was higher as compared to samples collected from the sites away from that sources. The results obtained by the "BIOMONITORING" technique, for the first time in this area, are presented.     

Atmospheric deposition fluxes of <Superscript>7</Superscript>Be, <Superscript>210</Superscript>Pb and <Superscript>210</Superscript>Po at Xiamen,China

The atmospheric deposition fluxes of ⁷Be, ²¹⁰Pb and ²¹⁰Po at Xiamen were measured. The samples were collected from March 2004 to April 2005 and the sampling period was one month. The ⁷Be and ²¹⁰Pb activity were measured using HPGe γ-spectrometer after concentration using Fe(OH)₃ co-precipitation method. The ²¹⁰Po was counted with an α-spectrometer after the sample was digested and spontaneous plated onto a silver planchet. At Xiamen, the atmospheric deposition fluxes of ⁷Be varied between 0.11 and 2.93 Bq·m⁻²·d⁻¹ and the average was 1.64 Bq·m⁻²·d⁻¹; ²¹⁰Pb fluxes varied between 0.04 and 0.85 Bq·m⁻²·d⁻¹, and the average was 0.51 Bq·m⁻²·d⁻¹; ²¹⁰Po fluxes varied between 0.002 and 0.133 Bq·m⁻²·d⁻¹, and the average was 0.061 Bq·m⁻²·d⁻¹. There were positive correlations between the deposition fluxes of ⁷Be, ²¹⁰Pb or ²¹⁰Po and the amount of precipitation. The residence time of aerosols varied between 6.0 and 54.0 days with a mean of 27.1 days, which were calculated by ²¹⁰Po/²¹⁰Pb fluxes ratios.     

Comparison of two solid-phase microextraction methods for the quantitative analysis of VOCs in indoor air

Competitive adsorption on adsorptive solid-phase microextraction (SPME) fibres implies careful determination of operating conditions for reliable quantitative analysis of VOCs in indoor air. With this objective, two analytical approaches, involving non-equilibrium and equilibrium extraction, were compared. The average detection limit obtained for GC-MS analysis of nine VOCs by the equilibrium method is 0.2 μg m⁻³, compared with 1.9 μg m⁻³ with the non-equilibrium method. The effect of the relative humidity of the air on the calibration plots was studied, and shown to affect acetone adsorption only. Hence, the concentrations that can be accurately determined are up to 9 μmol m⁻³. The methods were then applied to indoor air containing different concentrations of VOCs. The non-equilibrium method, involving short extraction time, can be used for detection of pollution peaks whereas equilibrium extraction is preferable for measurement of sub-μg m⁻³ ground concentration levels.      

Determination of lead in sediments and sewage sludge by on-line hydride-generation axial-view inductively-coupled plasma optical-emission spectrometry using slurry sampling

Among the “traditional” hydride-forming elements, lead is probably the most difficult, and its determination in this form has rarely been reported in the literature. In this paper a simple and rapid method, axial-view inductively-coupled plasma optical-emission spectrometry using on-line hydride generation (HG–ICP–OES) from samples prepared as slurry, is proposed for determination of lead in environmental samples. The samples (20–50 mg, particle size ≤120 μm) were treated with 1 mL aqua regia in a 40-kHz ultrasonic bath for 60 min. The slurry was diluted to a final volume of 50 mL with a 10% m/v solution of (NH₄)₂S₂O₈. The concentrations of NaBH₄, tartaric acid, and (NH₄)₂S₂O₈, used for on-line plumbane generation were optimized by means of a complete factorial analysis applied to an aqueous standard solution and to the slurry of a sediment certified reference material (CRM). External calibration against aqueous standards in the concentration range 10–100 μg L⁻¹ was used for analysis of six CRM—three marine sediments, one river sediment, and two sewage sludges. Analysis of the filtered slurry showed that Pb was only partially extracted into the liquid phase. Several major concomitants tested did not affect the Pb signal. The detection limit (3s, n = 10) for 20 mg sample in a final volume of 50 mL was 5.0 μg g⁻¹. Tin was the only other hydride-forming analyte that could be determined satisfactorily with Pb; for tin the detection limit was 1.0 μg g⁻¹. The values obtained for Pb and Sn were not significantly different from the certified concentrations, according to the t-test at the 95% confidence level. Nine river sediments collected locally were also analyzed and the concentrations were in agreement with results obtained after total digestion.     

Determination of lead concentration and lead isotope ratios in calcium supplements by inductively coupled plasma mass spectrometry after high pressure, high temperature digestion

The presence of lead as a contaminant in calcium supplements has aroused considerable public health interest in recent years. In this investigation lead and lead isotope ratios were determined by ICP-MS in ten brands of calcium supplements after high pressure/temperature digestion. Calcium supplements (200 to 250 mg) were digested in 2 mL of nitric acid at 230 °C and at a pressure of 1770 psi (1.2 × 10⁴ kPa). Lead concentrations were determined by matrix-matched lead standards prepared in a high-purity calcium carbonate matrix. Good recoveries of lead and calcium were obtained for certified animal bone reference material. High levels of Pb (8 to 28 μg Pb per g of calcium) were found in calcium supplements that contain dolomite or bone meal. Chelated and refined calcium supplements had lower Pb levels (0.8 to 0.9 μg Pb/g Ca). Application of lead isotope ratios to distinguish the origin of calcium sources was also explored. Received: 9 June 1998 / Revised: 20 July 1998 / Accepted: 25 July 1998     

Fallout of7Be in Damascus City

Atmospheric fallout of⁷Be was measured over a 2 year period (January 1995–January 1997) at Damascus city (33 N^o, 727 m above sea level). The annual total deposition of⁷Be was found to be 420 and 634 Bq·m⁻² for 1995 and 1996, respectively, reflecting a Mediterranean climate where two well recognized periods are dominant (wet and dry). The depositions in the wet periods were 303 Bq·m⁻² and 517 Bq·m⁻² for 1995 and 1996, respectively, while unexpected equal deposition rates in the two dry periods were found to be about 117 Bq·m⁻². In addition, monthly deposition rate of⁷Be showed a maxima in February in 1995 and January for 1996. Moreover, a comparison has been set for our measurements and other data obtained at different locations in the world.     

Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter

Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2004. Totally 30 sets of 24 h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal varia- tions and secondary pollution characteristics of fine particles during the sampling periods were dis-cussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respec-tively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol compo-nents in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South China Sea in summer, and the air quality was good. The prevailing wind in winter was from Mainland China to the north, and the polluted air mass led to poor air quality.