210Po concentration in different size fractions of aerosol likely contribution from industrial sources

The concentration of 210Po and 210Pb in vegetation, and their transfer from soil to vegetation and via aerosol deposited on foliage are well established. The available data show significantly higher levels of these radionuclides in ash from forest fires and aerosols downwind from industrial sites. The climate change-induced hot and dry conditions promote the spread of forest fires, which burn huge areas. On average, over 10 million hectares are reportedly lost annually. Large-scale forest fires and fossil-fuel and coal-operated Power and Desalination Plants are very likely to result in the dispersion of 210Pb and 210Po into the regional aerosol; such an effect has already been observed due to fires in Ukraine, Belarus, and Russia, which have led to the dispersion of 137Cs over large parts of Europe. We have measured elevated levels in Kuwait, and similar observations have been reported from Portugal. The higher levels of 210Po in PM2.5 raise a serious concern about an increased inhalation dose humans could receive. Our estimate shows that humans in areas affected by forest fires might receive a dose equivalent to 2 µSv d-1, which is significantly higher than 0.099 µSv d-1, the dose a person gets from smoking a packet of cigarettes daily. We propose that size-fractionated aerosol sampling should be taken up in regions affected by forest fires and industrial activities that add 210Po to the atmosphere in order to obtain a robust inhalation dose assessment and issue informed advisories to the public.

This study provides the first data set of 210Po and 210Pb activity concentrations in the organic and inorganic components of several particle size classes of aerosols collected at two sampling stations in Kuwait. The 210Po concentrations in the aerosols (Bq/g) were similar in all of the particle size classes, but as most (91%) of the aerosol load was made of fine fraction particles of PM0.39–2.5 µm, most of the 210Po activity was carried by this aerosol fraction. At the two sampling stations, the 210Po/210Pb activity concentration ratios in the aerosols were similar, stable around the year, and averaged 1.5 (range 1.2–1.9), much higher than the typical activity concentration ratios of these radionuclides in unmodified (background) aerosols, with Po/Pb < 0.1. The aerosol enrichment in 210Po was likely originated from the oil industry, specifically by gas flaring and oil refining in the Gulf region. Radionuclide analysis in the organic and inorganic components of aerosols showed that the 210Po concentration in the organic component was one order of magnitude higher than the 210Po concentration in the inorganic component, in contrast with 210Pb, which displayed similar concentrations in both organic and inorganic aerosol components. The 210Po carrying organic component of aerosols was investigated and it was found to be largely composed of microorganisms with high microbial and fungi diversity, with the phyla Proteobacteria, Ascomycota, and Basidiomycota being dominant among the bacteria and with Zygomycota being dominant among the fungi. Therefore, we are facing an active concentration process of the atmospheric 210Po carried out by microorganisms, which underlies the 210Po enrichment process in the organic component of aerosols. This bioconcentration of polonium in bioaerosols was unknown.

Air pollutants from industrial and urban sources contain harmful elements and chemical compounds. This work presents a study on background industrial and urban aerosol particles in the city of Nairobi. Its main focus was the understanding of elemental, black carbon (BC) and particulate mass (PM) concentrations in the perspective of identifying their sources. Aerosol particles were collected on Teflon filters in two size fractions, a fine fraction of particles having an aerodynamic diameter ( d a ) &lt; 2.5 µm and a coarse fraction with particles between 2.5 and 10 µm. A photometer and an energy dispersive x‐ray fluorescence spectrometer were used to analyse BC and trace elements (Si, S, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr and Pb), respectively. The sampled mass of the particulate matter was determined gravimetrically. The measured concentrations of the analysable species were dominated by BC, K and S in the fine fraction and Si, Ca and Fe in the coarse fraction. Principal component analysis and correlation evaluation of the fine fraction concentrations implicated industrial, vehicular and biomass‐burning emissions as the main sources of the measured elements. The average Pb concentration of 105 ng m −3 in the PM 10 samples at the background industrial site was approximately 20% of the air quality guideline (AQG) recommended by World Health Organisation (WHO). Most of the measured elements exhibited higher concentrations than those measured in Francistown in Botswana, Dar es Salaam in Tanzania and Edinburgh in United Kingdom but less than those measured in Barcelona in Spain and from previous studies in Nairobi. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Fifty-two stream-sediment samples, collected from an area south of Helena, Jefferson County, Montana, were sieved into two size fractions «88 ym, and between 88 and 149 ym) and analyzed for 80 different chemical species. Of these species, A3 showed detectable variation over the area, 31 were subjected to correlation analysis for the fine size fraction, and 30 for the coarse-size fraction. Two populations distinguished in the surface water samples of this study (Suits and Wenrich, 1981) are not as clearly evident in the stream sediments. However, stream-sediment samples from streams draining the Boulder batholith and from streams draining volcanics and volcanogenic sediments (referred to only as volcanics) do show differences in their geochemical relationships, especially between Si02» A^O-j and Na20 versus U. Thus, the sediments were also treated statistically as two lithologic populations as well as two populations based on size fraction. In the fine fraction samples, U ranged from 1.3 to 78 ppm, averaging 25 ppm for the Boulder batholith samples and 8 ppm for the volcanics samples. The range for the coarse fraction was 1.9 to 55 ppm with an average of 17 for the Boulder batholith group and 7 for the volcanics group. High U values (>50 ppm for the fine fraction) were encountered in samples from the Warm Springs Creek drainage area, along Prickly Pear Creek near Weimer and Golconda Creeks and along Muskrat Creek. All groups showed a significant correlation at the 99 percent confidence level (r between 0.73 and 0.77) between U and Th. Uranium was found to correlate significantly only with Th (as mentioned above) and with -Ni in the fine fraction of the volcanics group. U correlates significantly with -AloOo, Ba, organic C, -KoO, -Sr and Y in both size fractions for the Boulder batholith. Correlations between U and each of several elements differ for the fine and coarse fractions of the Boulder batholith group, suggesting that the U distribution in these stream sediments is in large part controlled by grain size. Correlations were found between U and CaO, Cr, ^2^3* -Na20, Sc, -SiC^, Ti02> Yb and Zr in the coarse fraction but not in the fine fraction. U correlates weakly (to the 90% confidence level, <?r<?< .37) with -Co and -Cu in the fine but not the coarse fraction. These results are compared to a previous study in the northern Absaroka mountains. Correlation coefficients between all other elements determined from these samples are also shown in Tables 12 to 15. INTRODUCTION This report presents chemical analyses and preliminary statistical evaluation of 52 stream-sediment samples collected in west-central Montana during July 1977. Geochemical sampling covers an area south of Helena, Montana located in the Jefferson City and Clancy 15-minute topographic quadrangles, Jefferson County (fig. 1). Additional, samples were collected within the boundaries of Helena and Deerlodge National Forests to the east and

Abstract:Identifying the provenance of aeolian sediments in the Hunshandake Sandy Land is of great importance for understanding the formation of the dune fields in the mid‐latitudes and for deciphering information about desert's responses to global change. By determining the major and trace elements concentrations of aeolian sands in three grain size fractions from the central and western parts of the Hunshandake Sandy Land, we systematically study the provenance and the depositional history of aeolian sands in this desert environment Our results show that aeolian sands from the Hunshandake Sandy Land are enriched in SiO2 and are depleted in many other elements compared to those of the Upper Continent Crust (UCC). Variations of the immobile elements ratios like Zr/Hf, La/Yb, Th/Nb, La/Nb, LaN/YbN, GdN/YbN are relatively large in the coarse and medium fractions but minor in the fine fractions. Eu anomalies are quite different in the coarse fractions, but mostly positive in the medium fractions and all negative in the fine fractions. Decreasing tendency of Zr concentrations from the west to the east in the Hunshandake Sandy Land is evident in the coarse sands but rather weak in the fine grain size fractions. Our geochemical data indicate that the sources for the coarse and medium fractions of aeolian sands are diverse, influenced by local geology and geomorphology, while the fine sand fractions are more homogenous due to intensive mixture mainly by aeolian processes. Various ratios of immobile elements suggest that these sands should be sourced primarily from the surrounding mountains by fluvial/alluvial processes rather than from any remote territories. Aeolian sands with Ce negative anomalies are widely distributed in the Hunshandake Sandy Land, indicating that aquatic environments have occurred extensively prior to the occurrence of the dune field.

Distribution and Partitioning of Polycyclic Aromatic Hydrocarbons (PAHs) in Different Size Fractions in Sediments from Boston Harbor, United States

Following the announcement of the retirement of the JOIDES Resolution drilling platform, it has become even more important to efficiently utilise the finite resource of marine sediment stored in IODP repositories. Marine sediments processed for inorganic geochemical analysis are often separated into fine (0.63 &amp;#181;m) fractions to help isolate benthic and planktonic foraminifera. However, organic matter can be associated with different particle size fractions and may have experienced different transport and diagenetic processes. Previous studies have suggested that sieving sediments into different size fractions does not affect the distribution of isoprenoidal [1,2] and branched glycerol dialkyl glycerol tetraethers (GDGTs) [3]. However, this has never been systematically investigated across a wide range of sample types (e.g., age, depositional environment, thermal maturity). It is also unclear whether size processing affects other lipid biomarker proxies (e.g., leaf waxes, alkenones).Here we test whether processing marine sediments into different size fractions influences lipid distributions by separating sediments into fine ( 0.63 &amp;#181;m) fractions and comparing these to corresponding bulk un-sieved sediments. Temperature reconstruction using the marine sea surface temperature proxy TEX86 shows relatively minimal deviation (average &amp;#177;0.12 TEX86 units, or ~2-3 &amp;#176;C) between the bulk un-sieved sediment (i.e,. control) and fine (10 &amp;#176;C). We also analysed leaf wax derived n-alkanes extracted from the marine sediment to evaluate the impact on terrestrial biomarkers. The average chain length shows similar deviation in both the fine (&amp;#177;0.21 units) and coarse (&amp;#177;0.21 units) fractions relative to the bulk sediment, suggesting that either fraction is suitable for interpreting first-order changes in vegetation type. &amp;#160;Moving forward, our results suggest that the fine fraction of grain size-sorted sediment yield similar lipid distributions compared to the bulk un-washed sediment. However, coarse fractions often show large deviations from the bulk sediment across different proxies, perhaps making these unsuitable for biomarker-based climate reconstruction.

Perfluorinated surfactants (PFSs) in size-fractionated street dust in Tokyo

Aerosol chemical mass closure during the EUROTRAC-2 AEROSOL Intercomparison 2000

As part of the Southern Africa Fire‐Atmosphere Research Initiative (SAFARI‐92), size‐fractionated aerosol samples were collected during September–October 1992 at three fixed ground‐based sites in the eastern Transvaal, i.e., at two sites within the Kruger National Park (KNP) and at a third site on the Transvaal highveld (about 150 km WSW of the KNP sites), and near a number of prescribed fires in the KNP. The collection devices consisted of stacked filter units, which separate the aerosol into a coarse (2–10 μm equivalent aerodynamic diameter (EAD)) and a fine (&lt;2 μm EAD) size fraction, and of eight‐stage cascade impactors, which provide more detailed size fractionation. The samples were analyzed for particulate mass (PM), black carbon (BC), and up to 47 elements. The prescribed fires gave rise to high levels of airborne soil dust, but several species (elements) were particularly enriched in the pyrogenic emissions. This was the case for BC, P, K, Ca, Mn, Zn, Sr, and I in the coarse fraction, and for BC, the halogens (Cl, Br, I), K, Cu, Zn, Rb, Sb, Cs, and Pb (and in the flaming phase also Na and S) in the fine fraction. The aerosol concentrations, compositions, and time trends at the two KNP sites were quite similar, suggesting that regionally representative samples were collected. Receptor modeling calculations, using both absolute principal component analysis and chemical mass balance, indicated that the KNP coarse PM was essentially attributable to mineral dust and sea salt, with average relative apportionments of 75% and 25%, respectively. At the highveld site, mineral dust and sea salt contributed in a 99‐to‐1 ratio to the coarse PM. In the fine size fraction at all three fixed sites, four components were identified, i.e., mineral dust, sea salt, biomass burning products, and sulfate. The pyrogenic component was the dominant contributor to the atmospheric concentrations of BC, K, Zn, and I, a major source for PM, Cl, Cu, Br, and Cs, but only a minor source for S. About 40% of the fine PM was, on the average, attributed to the pyrogenic particles, and about one third of it to the sulfate component. Relation of the time trends of the various components with three‐dimensional air mass back trajectories indicated that elevated levels of pyrogenic products were mostly found in air masses arriving from the north. The levels of the sulfate component tended to be higher at the highveld site than at the two KNP sites, and this component was generally associated with continental air. It was concluded that the major contribution to this fine sulfate came from fossil fuel burning and various industrial activities on the Transvaal highveld.

Measurements of gaseous SO2, NO, NO2, H2S, O3, NH3 and VOCs, in Kuwait city using IVL passive sampler technology, were obtained on monthly basis during the period from March 2011 to February 2012 at 10 locations. The results of this study reveal that those compounds had low concentrations compared to Kuwait Environment Public Authority standards for residential areas. It is found that nitrogen oxides, benzene and xylene were mostly emitted from motor vehicles; in contrast, industrial sources including oil industries were a major contributor to sulfur dioxide and toluene pollution. Higher concentrations of NOx and SO2 were recorded during winter season where the inversion layer is quite pronounced thus trapping more pollutants in ambient air, while higher O3 values were recorded in summer period; the hot season in Kuwait. The spatial distributions of the measured gaseous air pollutants were extremely consistent with the influence of the prevailing wind direction NW. In general and except for PM10, the yearly average air quality indices (AQI) of SO2, NO2, CO and O3 concentrations are coming under the category of “good” and “moderate”.

Provenance of sediments deposited at paleolake San Felipe, western Sonora Desert: Implications to regimes of summer and winter precipitation during last 50 cal kyr BP

Lignin, elemental, and stable carbon isotope compositions are reported for local plants and for coarse (&gt;63 µm) and fine (&lt;63 µm) suspended particulate materials collected along a 1,950‐km reach of the lower Amazon River during four contrasting stages of the 1982–1983 hydrograph. Fluxes of chemically recognizable lignin in the two size classes generally parallel each other along the mainstem with the fine fraction usually predominating. Particulate organic matter transported in the coarse size fraction of the mainstem and its major tributaries is composed of recently formed and well preserved tree leaf debris along with some wood. Organic matter in the fine size fraction is comparatively old, degraded, and rich in immobilized nitrogen and derives primarily from soils. C‐4 grasses, which are abundant in the mainstem floodplain (várzea), are not major components of either the coarse or fine particulate material in the river.Particulate organic matter in both size fractions is introduced largely from upstream sources within the Rio Solimões and Rio Madeira drainage basins. Most of this organic matter is unreactive and is transported conservatively with mineral particles along the Amazon mainstem. However, some downstream compositional trends are seen in both size fractions which reflect the addition or exchange of highly degraded, 13C‐depleted, and lignin‐poor organic materials from lower basin sources.

Three 2-wk seasonal field campaigns were performed in 2003 and 2004 at a sampling site on the southern Tyrrhenian coast of Italy with the aim to investigate the dynamics and characteristics of particle-bound pollutants in the Mediterranean area. Fine (PM2.5) and coarse particulate matter (PM10–2.5) size fractions were collected by a manual dichotomous sampler on 37-mm Teflon filters over a 24-hr sampling period. On average, 70% of the total PM10 (PM2.5 + PM10–2.5) mass was associated with the coarse fraction and 30% with the fine fraction during the three campaigns. The ambient concentrations of Pb, Ni, Cr, Zn, Mn, V, Cd, Fe, Cu, Ca, and Mg associated with both size fractions were determined by atomic absorption spec-trometry. Ambient concentrations showed differences in their absolute value, ranging from few ng · m-3 to µg •m-3, as well as in their variability within the PM2.5 and PM10–2.5 size fractions. PM10 levels were well below the European Union (EU) limit value during the study period with the exception of three events during the first campaign (fall) and five events during the third campaign (spring). Two main sources were identified as the major contributors including mineral dust, transported from North Africa, and sea spray from the Tyrrhenian Sea. Comparing the results with backward trajectories, calculated using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) and Total Ozone Mapping Spectrometer-National Aeronautics and Space Administration (TOMS-NASA) maps, it was observed that in central and eastern Europe, the Tyrrhenian Sea and North Africa were the major emission source regions that affected the temporal variations and daily averages of PM2.5 and PM10–2.5 concentrations.

Environmental magnetic approach towards the quantification of pollution in Kathmandu urban area, Nepal