Average Element Concentrations Research Articles

Accurate quantification of melt inclusion chemistry by LA-ICPMS: a comparison with EMP and SIMS and advantages and possible limitations of these methods

Laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) has recently emerged as a powerful in situ microanalytical technique for major to trace elements in heterogeneous samples such as fluid and melt inclusions. Here, a rigorous comparison of melt inclusion (MI) data acquired by electron microprobe (EMP), ion microprobe (the secondary ion mass spectrometry, SIMS) and LA-ICPMS is used to evaluate the applicability and advantages/drawbacks of these approaches. We are specifically interested in determining if LA-ICPMS data on entire, unexposed, crystallized MI that cannot be homogenized in the lab are accurate and of a useful precision. Quantification of LA-ICPMS MI signals requires the use of an internal standard, i.e., the concentration of one element, or an element ratio, at the time of MI entrapment must be known independently, in order to derive the pure MI composition from the MI plus host mixed signal. Analysis of plagioclase-hosted glassy MI of a mid-ocean ridge basalt (MORB) sample from the East Pacific Rise illustrates that melt inclusion chemistry can be accurately quantified by LA-ICPMS, including the correction for postentrapment sidewall crystallisation of the host mineral without prior reheating in the lab. The LA-ICPMS data obtained on crystallized MI demonstrate agreement with the EMP and SIMS data on exposed glassy MI at the 1 standard deviation uncertainty level except for a few elements close to their limits of detection. LA-ICPMS data reduction schemes include the quantification of analytical uncertainty on each element of single MI. Therefore, weighted average element concentrations can be obtained for MI assemblages, at precisions that compare well with those of average element concentrations obtained by EMP and SIMS. Simple sample preparation minimizing inclusion loss through polishing combined with the analytical efficiency of 50 inclusions plus neighbouring host mineral at up to 40 elements per day enable the collection of statistically relevant datasets by LA-ICPMS. These allow to recognize nonrepresentative MI (e.g., heterogeneous entrapment). Application to individual clinopyroxene crystals from the AD79 pumice horizon of Mt. Somma-Vesuvius reveals chemical variability that exceeds the analytical precision on single melt inclusions. This variability was not obvious from the limited data set obtained by SIMS and EMP. The largest source of nonquantifiable error for EMP and SIMS data stems from the requirement of reheating the melt inclusions in the lab in order to reverse postentrapment crystallisation onto inclusion walls or growth of crystallites. For LA-ICPMS analysis of unexposed MI, the reliability with which the internal standard (IS) element concentration is known determines the quality of the data. LA-ICPMS, however, cannot analyse H 2O, F, S and Cl reliably, has higher limits of detection (LODs) than SIMS for some elements for MI below ∼25 μm, has lower spatial resolution than both EMP and SIMS and consumes much more sample per analysis. Therefore, EMP, SIMS and LA-ICPMS are complementary in MI research, and the type of application will determine the analytical method or methods of choice.

Material transport between the atmosphere and sediment of the Lake Balaton

A monitoring system was developed to gain information on the present level of pollutants in the Lake Balaton, Hungary. Determination of 13 polycyclic aromatic hydrocarbons (PAHs) and inorganic pollutants (mostly toxic metals) in aerosol, precipitation and sediment samples was carried out. The aim of collecting aerosol and precipitate samples in the same site at the same period was to determine the distribution of elements in two depositions. For the fractionation by particle size, aerosols were sampled by a cascade impactor. A simple three-stage sequential leaching procedure was applied to establish the distribution of metals among environmentally mobile, bound to carbonates and oxides, and environmentally immobile, (bound to silicates) fractions in aerosols. Sediment samples were collected from 17 different sites inside of the lake and 10 sites at harbors at 30–70 cm in depth. Core samples were cut to 10-cm pieces, dried at room temperature, and finally passed through a 63-μm sieve. Total concentrations of elements were determined by atomic absorption spectrometry (AAS) after an acidic digestion. The concentrations of PAHs were determined by HPLC method with fluorescence detection. In aerosol samples collected from September 6, 2002 to January 26, 2003, concentration of Cd was <0.1 μg/m 3, and the majority of Cd has been found in the mobile fraction. Cadmium was associated to particles between 0.25 and 2 μm indicating the anthropogenic origin. Similar distribution of Pb was obtained in all seasons, and the highest concentration of Pb was found as 8.6 ng/m 3 in particle size of 0.7 and 1.4 μm. Results of total concentration of elements of bottom sediments of the Lake Balaton and harbors were compared to Interim Sediment Quality Guideline (ISQG) values and the Probable Effect Level (PEL) values. Data showed that the average concentrations of elements were usually less than those of ISQGs and other background data for soils and geochemical values. The sediment is not polluted and its disposal is feasible. There is no direct correlation between the concentration of elements deposited onto the surface of the lake from dry and wet deposition and the upper part of the sediment. So, from the budget of the deposition, the concentration of elements in the upper layer of the sediment cannot be predicted. Seasonal changes of the concentration of PAHs in aerosol was observed, samples collected at winter contained the highest values. In December–January 2002/2003, the wet deposition was found as 64 μg/m 2 period. Among the individual compounds, the wet deposition rate of phenantrane, fluoranthene and pyrene was dominant, while for dry deposition, these compounds were fluoranthene and pyrene. The concentrations of ∑PAHs found for all sites and depth of sediment samples ranged from 11 to 1734 μg/kg dry weight with an average of 132 μg/kg. These values represent a quite low pollution level compared to other sediment with anthropogenic influence. Based on the results, it can be definitely confirmed that the chemical quality of the water and sediment of the Lake Balaton is satisfactory.

Ontogenetic trace element distribution in brachiopod shells: an indicator of original seawater chemistry

Articulated fossil brachiopod shells have been used extensively to extract primary chemical information of Phanerozoic seawater. Despite the selection of well-preserved shells using trace element, microstructure and cathodoluminescence criteria, there are still concerns as to whether the selected brachiopod shells do indeed contain original seawater signals. Analyzed in-situ by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LAICPMS), Sr, Na, Mg, Mn, B and Ba distribute symmetrically in shell transects of the modern brachiopods Magellania flavescens and Terebratulina septentrionalis. Symmetry of the trace element distribution pattern is considered an intrinsic and original ontogenetic property of the brachiopod shell chemistry. The trace element distribution is symmetrical in a well-preserved shell of the Devonian brachiopod Independatrypa lemma, indicating that the selected shell by the conventional criteria has preserved its original seawater signal for 400 Ma. In another specimen of I. lemma that is considered diagenetically altered, trace element concentrations are asymmetrically distributed in the shell. The agreement between the distribution criteria and the conventional methods indicates the latter can be used to select brachiopod shells with original seawater chemistry. The average element concentration in the whole shell of unaltered brachiopods should be a reflection of the seawater chemistry, while its change in different part of a shell reflects ontogenetic effect, and its high frequent fluctuations in a transect are results of changes in environmental parameters with seasonal or annual characteristics.

Litterflow chemistry and nutrient uptake from the forest floor in northwest Amazonian forest ecosystems

Samples of the fraction of net rainfall passing through the forest floor collected at monthly intervals in four pristine forests in Colombian Amazonia, during the period between 1995–1997 were analysed for solute concentrations to estimate the element fluxes from the forest floor into the mineral soil and root nutrient uptake from these forest floors. Results were compared with inputs by throughfall, stemflow, litterfall and fine root decay. Element concentrations were tested for their relationship with litterflow amounts, rainfall intensity and length of the antecedent dry period and differences in element fluxes between ecosystems were assessed. Concentrations of elements in litterflow followed a similar pattern as those in throughfall, which indicates that element outputs from the forest floor are strongly related to those inputs in throughfall. In the forests studied, the average concentrations of elements as K, Mg, orthoP and the pH of the litterflow decreased relative to that in throughfall in most events, while the concentration of elements such as dissolved organic carbon, H, SO4 and Si increased in litterflow from these forests. Element concentrations in litterflow showed a poor correlation with variables such as litterflow amounts, rainfall intensity and antecedent dry period, except for K which showed a significant correlation (p>0.95) with analysed variables in all forests. Outputs were significantly different between forests (p>0.95); these fluxes, which particularly concerned cations, being the largest in the flood plain, while for anions outputs increased from the flood plain to the sedimentary plain. After adding the nutrient contributed by litter decomposition and fine root decay, the net outputs of main elements from the forest floors were still smaller than inputs by net precipitation (throughfall + stemflow) indicating that the litter layers clearly acted as a sink for most nutrients. Accordingly, the element balances confirm that the forest floors acted as a sink for nutrients coming in by throughfall, stemflow, litterfall and fine root decomposition. P, Mg and N appeared to be the most limiting nutrients and the forests studied efficiently recycled these nutrients.

A preliminary study on the enrichment mechanism and occurrence of hazardous trace elements in the Tertiary lignite from the Shenbei coalfield, China

The Cr and Ni contents are high in the Eocene lignite of the Shenbei coalfield, which is a small intracontinental basin located in Liaoning Province, China. In this paper, we studied the distribution, origin and occurrence of Cr, Ni and other hazardous trace elements in the Shenbei lignite on the basis of coal petrology, and geochemistry of the lignite and combustion products. The following conclusions on the Shenbei lignite can be drawn: (1) The dominant maceral group in the Shenbei coal is huminite (humodetrinite), accounting for 96%–99% of the total maceral. Inertinite content is less than 1%. Liptinite content (sporinite and cutinite) is 0.2–1.6%. Common minerals in the Shenbei lignite include clay minerals (kaolinite), pyrite and quartz, and calcite and siderite. Chromite is not present in the lignite. (2) Potentially hazardous trace elements such as Co (22 μg/g), Cr (79 μg/g), Cu (63 μg/g), Zn (93 μg/g), V (88 μg/g) and Ni (75 μg/g) are strongly enriched in the Shenbei lignite compared with average concentration of trace elements in the Chinese coal and worldwide lignite. These elements are mainly associated with fulvic acid (FA) and/or coal organic macromolecular compounds in most of the studied lignite samples, indicating an organic association and enrichment of these elements in the Shenbei lignite. (3) Unusually high trace elements contents in the Shenbei lignite are derived mainly from the olivine basalt (country rock of coal basin) that consists of 52.7% plagioclase, 17.8% pyroxene, 14% olivine and 15.5% Ti–Fe oxide minerals. These olivine basalts have higher Cr, Ni, Pb and Zn contents than other types of rock and worldwide basalts do. (4) Fly ash of the Shenbei lignite, with 90% 1–50 μm amorphous particles and 8% 1–10 μm cenosphere, has high contents of Zn (23,707 μg/g), Be (12 μg/g), Sr (1574 μg/g), Pb (486 μg/g) and Cr (349 μg/g). In particular, the ferruginous micro-cenoshperes contain 1–12.79% Zn. Fine bottom ash (<0.031mm) of the Shenbei lignite has higher contents for most of the elements with the exception of Mo, Sn and Zn. Therefore, the potentially environmental and health impact of the fly ash and fine bottom ash should constitute a major concern.

Different accumulation of elements in the rami of the coronary arteries of Thai.

To analyze the accumulation of elements in the rami of the coronary arteries, the authors determined element contents in both the coronary arteries and their rami of the Thai by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 13 men and 6 women, ranging in age from 34 to 83 yr. It was found that a higher accumulation of calcium and phosphorus occurred in the proximal sites of coronary arteries such as the anterior descending, right coronary, left coronary, and circumflex arteries than the distal sites such as the diagonal, lateral, conus, acute marginal, and posterior descending arteries. The accumulation of calcium and phosphorus in the anterior descending and right coronary arteries of the Thai increased remarkably in the fifties, thereafter decreased, and increased again in the eighties. It should be noted that a very high accumulation of calcium and phosphorus in the coronary arteries occurred in the fifties. In regard to relationships among the average contents of elements in the coronary arteries and their rami, it was found that there were very significant direct correlations between calcium and phosphorus contents, between calcium and magnesium contents, and between phosphorus and magnesium contents. These results suggested that as calcium and phosphorus increased in the coronary arteries and their rami, magnesium increased simultaneously in all of the coronary arteries and their rami.

Ambient concentrations and dry deposition fluxes of trace elements in Izmir, Turkey

Dry deposition samples were collected using a smooth surrogate surface at the Kaynaklar Campus of the Dokuz Eylul University in Izmir, Turkey. Concurrently ambient aerosol samples were collected. All samples were analyzed for anthropogenic and crustal trace elements. The average trace element concentrations and fluxes measured in this study were generally higher than those reported previously for urban and rural areas. The contribution of local terrestrial and anthropogenic sources were also investigated using enrichment factors (EFs) calculated relative to the local soil. Relatively lower EFs for ambient samples and high ambient concentrations indicated that the local soil was polluted and contributed significantly to ambient trace element concentrations. Deposition samples had higher EFs than the air samples. The EF sequences of trace elements were also different for deposition and ambient samples, probably due to the fact they have different mass median diameters and deposition velocities. The overall dry deposition velocities for trace elements calculated by dividing the particulate fluxes measured with the surrogate surfaces by ambient concentrations ranged from 0.6 (Al) to 6.2 cm s −1 (Fe). The agreement between the experimental dry deposition velocities determined in this study and the previously reported ones using similar techniques for trace elements was good.

Epigenetic origin of celestite deposits in the Tertiary Sivas Basin: new mineralogical and geochemical evidence

The occurrence of celestite in the evaporitic Upper Eocene-Miocene deposits of the Sivas (Ulas) Basin is documented. This paper aims to demonstrate that a group of Tertiary sediment-hosted celestite deposits are epigenetic in origin, rather than syngenetic as has been claimed by a number of previous workers. Thin section petrography, fluid inclusion data, mineral and whole rock geochemistry and isotopic compositions (87/86Sr, 180 and 34/32S) are the main tools employed. The celestite occurs as stratabound, vug-filling, nodular and lenticular types. Petrographic, microtextural (SEM), mineralogical and geochemical analyses indicate that the celestite can be classified as pure, calcareous and gypsiferous varieties. The celestite under polarizing microscope shows xenomorph, pseudomorph and acicular-radial crystal structures. Scanning electron microscope (SEM) analyses reveal abundant zonal structures in single crystals. Ore minerals associated with the celestite mineralization include pyrite (especially bravoite-melnikovite), marcasite, limonite, siderite-ankerite, gold (electrum-nabite), psilomelane, realgar-orpiment, antimony and dedritic chromite. X-ray fluorescense analyses indicate that the celestites contain 53-58 wt.% SrO, 0.05-3.70wt.% BaO, 0.02-3.40b wt.% CaO and 35-44wt.% SO 3 . Average minor element contents are: 0.4 wt.% SiO 2 , 0.9 wt.% Al 2 O 3 , 0.03 wt.% MnO, 0.3 wt.% MgO and 0.3 wt.% Na 2 O. The trace elements recognized are: Mo (1.8 ppm), Pb (18 ppm), W (0.8 ppm), As (2.3ppm), Zn (4ppm) and Cu (7ppm). The homogenization temperatures of fluid inclusions in celestite crystals vary between 210 and 390 °C. Salinity (NaCI equ.) values range from 11 to 23 wt.% NaCl. Fig. 1. A Location of the Tertiary Sivas Basin, Turkey. B Location map of the study area in the Sivas Basin. C Simplified geological map of the study area, showing the location of celestite and celestite-barite (Ba, Sr)SO 4 occurrences. The petrographic, mineralogical, geochemical and isotopic characteristics of the celestite deposits in the Sivas (Ulas) basin are compatible with an epithermalhydrothermal, rather than a sedimentary origin as it was previously proposed. A hydrothermal origin is also supported by the Sr isotope data; since the 8 7 Sr/ 8 6 Sr ratio varries between 0.70590 and 0.70718. Besides, the results of the 1 8 O and 3 4 S/ 3 2 S isotope data are in accordance with the hydrothermal origin.

Investigation on the pollution sources of bottom sediments in the Lake Balaton

A modified four-step sequential extraction procedure was applied to determine the distribution of elements in bottom sediment samples collected inside the Lake Balaton, from rivers of its catchment area and seven harbors around the lake. The fractions were: (1) exchangeable and bound to carbonate; (2) bound to Fe/Mn oxide; (3) bound to organic matter/sulfides; and (4) acid soluble. Samples were taken in three seasons and the mean concentration of the elements was calculated. Ten elements were investigated and Cu, Pb and Zn were chosen to discuss in detail. The pollution sources have been identified in a monitoring system. Results were compared to Hungarian soils, geochemical background values, sediment quality values (SQVs) and sediment background values (SBVs). Records showed that the average concentration of elements was usually less than that of SQVs and other data for soils. However, some extremely high concentrations at different sampling sites surpassed the geochemical background values. Most of the elements were found in the acid soluble fraction indicating stable compounds in sediments. Based on the results, it can be definitely confirmed that the quality of the sediment inside the Lake Balaton is satisfactory.

Determination of Residual Carbon and Nitrogen in Glow Discharge Lamp for Optical Emission Spectrometry

6.7%) for the calibration of nitrogen. The intensity of each line was measured by a bulk analysis mode, a depth profile mode, and the diagnostics mode. Average intensities were measured by a bulk analysis mode with a specified integration time and then used to calculate average concentrations of elements in a sample. In this work, the intensity of the bulk mode was measured with the integration time of 10 seconds after the pre-sputtering of 3 minutes. The intensity as a function of time was measured by the depth profile mode. And the peak of analytical line was scanned by the diagnostics mode. The scanning of peak was used to characterize the shape of peaks, backgrounds and so on. The background intensity was obtained at the wavelength of peak maximum from the interpolation of measured intensities at the proper both sides of the analytical line. The calibration curves were prepared by plotting the background-corrected peak intensity versus the analyte concentrations in the standards. The concentrations of residual carbon and nitrogen were calculated with the slope and the intercept of calibration curve.

Plume-driven upwelling under central Iceland

A suite of 70 basaltic samples from the Herdubreid region of the Northern Volcanic Zone (NVZ) in central Iceland has been analysed for major and trace element compositions. The average light rare earth element concentration of these basalts is more than a factor of 2 higher than that of basalts from the Theistareykir volcanic system near the northern end of the NVZ. Seismic surveys of the NVZ have shown that the crustal thickness increases from ∼20 km near Theistareykir to 32–40 km in central Iceland. The observed REE composition and crustal thickness of the Theistareykir area can be reproduced by a melting model where mantle with a potential temperature of ∼1480°C upwells under the spreading ridge and the mantle upwelling is driven by plate separation alone. However, plate-driven upwelling models cannot simultaneously reproduce the composition of the Herdubreid region lava and the observed crustal thickness. Forward and inverse techniques show that plate-driven models that match the crustal thickness underestimate the La concentration by more than a factor of 2, and models that reproduce the compositions underestimate the crustal thickness by a factor of 4–5. Therefore one of the assumptions involved in the plate-driven upwelling models is not appropriate for central Iceland. A new set of models was developed in which mantle upwelling rates are allowed to differ from those of plate-driven upwelling in order to investigate the role of plume-driven mantle upwelling. The lava composition and crustal thickness of the Herdubreid region can be reproduced by models where the upwelling rates near the base of the melting region (>100 km depth) are ∼10 times higher than those expected from plate-driven upwelling alone and the mantle potential temperature is 1480–1520°C. About half of the melt generation under central Iceland results from plume-driven upwelling, with the remainder caused by plate-driven upwelling of hot material. This result is in agreement with numerical models of ridge-centred plumes.

Radioactivity and heavy metal composition of Nigerian phosphate rocks: possible environmental implications

Phosphate rock samples collected from the Dange Formation within the Sokoto basin were analyzed for trace element constituents using instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRFA) techniques, while natural activity concentrations due to 238U, 232Th, and 40K were determined by γ-ray spectrometry. The analytical results show that the average concentrations of some toxic elements (As, Sb, Cr, and Zn) in phosphate rocks are not appreciably different from that in agricultural soils. However the U and Th contents are enriched significantly in comparison. The results were used to assess the environmental toxicity of heavy metals and radiation hazard attributable to the direct application of phosphate rock as fertilizer.

Rhenium‐osmium isotope systematics and platinum group element concentrations: Loess and the upper continental crust

We investigate the use of loess as a proxy for the concentration and isotopic composition of highly siderophile elements, specifically Os, in the upper continental crust. The 187Os/188Os, platinum group element, and Re concentrations of 16 loess samples from China, Europe, and South America, previously analyzed for major, trace element, and Sr and Nd isotope composition, reveal subtle differences between loess provinces. Despite those differences, the 187Os/188Os of 1.05 ± 0.23 is surprisingly homogenous. Average 187Os/188Os as well as average Os (31 pg/g) and Ir (22 pg/g) concentrations are similar to the lower limit of previous estimates for average upper continental crust, whereas Ru, Pt, and Pd concentrations are intermediate between previous estimates. We argue that hydrogenous enrichment of Os in riverine sediments led Esser and Turekian [1993] to overestimate the Os concentration of upper continental crust (50 pg/g). On the basis of this argument and correlations with major and trace elements we propose that average platinum group element concentrations of loess (i.e., 31 pg Os/g, 22 pg Ir/g, 210 pg Ru/g, 510 pg Pt/g, 520 pg Pd/g) are a proxy for the upper continental crust. We further suggest that the nonchondritic average Os/Ir of 1.4 reflects the combined effects of radiogenic ingrowth of Os from Re decay over the mean lifetime of the upper continental crust and preferential return of Os to the crust during subduction. Rhenium concentrations scatter significantly, with highest values in loess derived from organic‐rich sedimentary rocks. Low median Re concentrations most likely reflect depletion of loess in organic matter, an important sink for Re in the upper continental crust. An average 187Re/188Os of 34.5 was calculated on the basis of the measured 187Os/188Os and Nd model ages. This value corresponds to a Re concentration of 198 pg/g. Correcting measured 187Os/188Os = 1.05 and inferred 186Os/188Os = 0.119871 (from 190Pt/188Os = 0.0176) for the older mean age (2.2 Gyr) of upper continental crust compared to loess (1.6 Gyr) yields average upper crustal 187Os/188Os of 1.40 and 186Os/188Os of 0.119885.

LI, Y.-H. 2000. A Compendium of Geochemistry. From Solar Nebula to the Human Brain. xiii + 475 pp. Princeton, Oxford: Princeton University Press. Price US $70 (domestic), £44.00 (international); hard covers. ISBN 0 691 00938 4.

LI, Y.-H. 2000. A Compendium of Geochemistry. From Solar Nebula to the Human Brain. xiii + 475 pp. Princeton, Oxford: Princeton University Press. Price US $70 (domestic), £44.00 (international); hard covers. ISBN 0 691 00938 4. - Volume 138 Issue 5

Elemental concentrations in different species of seaweeds from Loreto Bay, Baja California Sur, Mexico: implications for the geochemical control of metals in algal tissue

Concentration levels of 21 elements were analyzed by instrumental neutron activation analysis (Rb, Cs, Ca, Sr, Ba, Sc, Cr, Fe, Co, Ni, Zn, Se, As, Sb, Th, U, Br, Hf, Ta, Zr, and Ag) in seven different seaweed species ( Codium cuneatum, Sargassum sinicola, Padina durvillaei, Laurencia johnstonii, L. papillosa, Gracilaria pachidermatica and Hypnea pannosa), collected in a shallow coastal zone from Bahia de Loreto, Baja California Sur, Mexico. Measured concentrations in algal tissue spanned almost eight orders of magnitude (from 2.0×10 −3 μg g −1 for Hf to 1.2×10 5 μg g −1 for Ca). Ca was consistently the most abundant element in all analyzed seaweeds, followed by Fe and Sr. Brown algae showed a tendency to incorporate higher concentrations of elements than red and green algae. Additionally, there were significant linear correlations ( P<0.05 to P<0.001) between a total of 76 different pairs of elements, some of them (e.g. Rb–Ni, Rb–Ag, Sc–Cr, Sc–Fe, Sc–Ni, Sc–Hf, Cr–Fe, Fe–Ni, Fe–Hf and Ni–Th) highly correlated ( r 2>0.900). A significant correlation ( r 2=0.701, n=18, P<0.001) exists between our measurements in the tissue of algae and their corresponding average elemental concentrations in oceanic water from the North Pacific Ocean. Hence, overall elemental abundance in algal tissue apparently is controlled by the elemental abundance in oceanic water, whereas metabolic processes as well as environmental factors relevant to each region modify the final concentration of a given element in the body of a macroalgae.

PM 10 measurements at McMurdo Station, Antarctica

PM 10 aerosols at McMurdo Station, Antarctica were sampled continuously during the austral summers of 1995–1996 and 1996–1997. PM 10 (particles with aerodynamic diameters less than 10 μm) mass concentrations at Hut Point, located less than 1 km from downtown McMurdo, averaged 3.4 μg m −3, more than an order of magnitude lower than the USEPA annual average National Ambient Air Quality Standard (NAAQS) of 50 μg m −3. Concentrations of methanesulfonate and nitrate were similar to those measured at other Antarctic coastal sites. Non-sea-salt sulfate (NSS) concentrations on Ross Island were higher than those found at other coastal locations. The average elemental carbon concentration (129 ng m −3) downwind of the station was two orders of magnitude higher than those measured at remote coastal and inland Antarctic sites during summer. Average sulfur dioxide concentrations (746 ng m −3) were 3–44 times higher than those reported for coastal Antarctica. Concentrations of Pb and Zn were 17 and 46 times higher than those reported for the South Pole. A methanesulfonate to biogenic sulfate ratio ( R) of 0.47 was derived that is consistent with the proposed temperature dependence of R.

Characterization of ophiolites from northern Havana-Matanzas petroleum fields using instrumental neutron activation analysis

Concentrations of 16 elements from 14 serpentinitic samples from Basilio and Cantel petroleum fields were obtained by instrumental neutron activation analysis (INAA): Cr, Co, Ni, La, Nd, Sm, Eu, Gd, Tb, Ce Yb, Lu, Rb, Cs, Hf and Th. Relative INAA was performed using certified reference materials and laboratory standards. Average elemental concentrations showed that the ophiolites have a basic character, suggesting the use of a well-logging method designed for volcano-sedimentary petroleum fields.

The concentration, trend and seasonal variation of metals in the atmosphere in 16 Japanese cities shown by the results of National Air Surveillance Network (NASN) from 1974 to 1996

In this study, the data from National Air Surveillance Network (NASN) for selected crustal elements (Al, Ca, Fe, Mn, Sc and Ti), anthropogenic elements (As, Cu, Cr, Ni, Pb, V and Zn) and a marine element (Na) in atmospheric particulate matter have been evaluated over Japan from 1974 to 1996. The NASN had 16 sampling stations, Nopporo, Sapporo, Nonotake, Sendai, Niigata, Tokyo, Kawasaki, Nagoya, Kyoto-Hachiman, Osaka, Amagasaki, Kurashiki, Matsue, Ube, Chikugo-Ogori and Ohmuta in Japan, at which aerosols were regularly collected every month and samples collected by low volume air sampler were analyzed by neutron activation analysis (NAA) and X-ray fluorescence (XRF). Results of trend analysis showed that the annual average concentrations of crustal and anthropogenic elements decreased significantly between 1974 and 1996. Furthermore, the concentrations of selected crustal and anthropogenic elements were higher between 1974 and 1979 than between 1980 and 1989. Crustal elements displayed high concentrations in the “Kosa” period (the dust season from March to May) and in winter (November and December) and low concentrations in summer (July and August). The ratios of elemental average concentrations in the Kosa period to those of summer were 2–5 times higher and those of winter relative to those of summer were 1.5–3 times higher for crustally derived elements. Particularly, concentration of Sc in Matsue was 8 times higher during the Kosa period than during summer time. Some of anthropogenic elements also showed high concentrations in the Kosa Season and low concentrations in summer. The ratios of elemental concentration in the Kosa period to those of summer and those of winter relative to summer were 2–4 times higher for some anthropogenically derived elements. Especially, the concentration of Zn in Chikugo-Ogori was 5.7 times higher during wintertime than during summertime.

Determination of concentrations of elements in the atmospheric aerosol of the urban and rural areas of Beijing in winter.

The proton-induced X-ray emission technique is one of the most suitable methods in the study of the multielement content of atmospheric aerosols. Atmospheric aerosol samples were collected in winter using an eight-stage cascade impactor at a site of the urban center and a rural site of Beijing. The aerosol samples collected were analyzed to determine maximum, minimum, and average concentrations of up to 20 elements and the ratios of the average element concentrations for the coarse to fine particles (C/F) by the PIXE technique. It has been found that the average elemental concentrations in the urban center are higher than those in the rural area, except S and Br. The concentrations for S and Pb in the atmospheric aerosols are found to be less than the results of previous measurement, but their concentrations in the fine particles increased in winter in the samples from the urban center. The deposition probability of the International Commission on Radiological Protection (ICRP) mode and the mass particle-size distributions of the elements determined in the urban center have been utilized to evaluate inhalable particulate matter fractions retained in the three regions of one's respiratory tract and their harm to human health is discussed.

Contaminant residue levels in arctic wolves ( Canis lupus) from the Yukon Territory, Canada

Kidney, liver and bone samples were taken from 19 wolves ( Canis lupus) collected from two locations in the Yukon Territory. Liver samples pooled by age and sex were analyzed for 22 organochlorine pesticides and 101 PCB congeners. Individual kidney and liver samples were analyzed for arsenic, cadmium, copper, lead, total mercury, selenium and zinc. Thirteen individual bone samples were analyzed for lead. While most organochlorines were not present at detectable levels in wolf liver, some chlorobenzenes, dieldrin and Σ PCB were present at low levels. PCB congeners 149, 153, 170/190, 180 and 187/182 made up 86% of the total PCBs measured in wolf liver. The hexa- and heptachlorobiphenyls dominated the pattern in wolf liver, while congeners containing less than five chlorine atoms were not detected. The pattern of chlorobenzene and PCB homologues found in wolf liver are more similar to those found in marten ( Martes americana) and other carnivores than caribou ( Rangifer tarandus), perhaps reflecting similarities in food habits and metabolic capacities. With the exception of cadmium, average element concentrations in all wolf tissues are similar to those found in other arctic carnivores. Cadmium concentrations in wolf liver and kidney were somewhat higher in Yukon wolves than other arctic wolves. This may reflect high cadmium concentrations found in livers and kidneys of moose and some caribou herds in the Yukon. Renal arsenic and bone lead decreased significantly with age in wolves, while renal mercury increased with age. Because the ranges seen are relatively small, and all values are within the range normally seen in wildlife, it is difficult to determine the biological significance of these relationships. Contaminant levels in Yukon wolves are generally low and are similar to those found in other arctic terrestrial carnivores. They do not approach levels that are known to potentially cause adverse effects in animals. Contaminant concentrations found in this study should be considered baseline levels.