Abstract  The disequilibrium between 234U and 238U is commonly used as a tracer of groundwater flow. This paper aims to identify uranium contents and uranium isotopic disequilibria variation in groundwater sampled from deep Continental Intercalaire aquifer (southern Algeria and Tunisia). Large variations in both U contents (0.006-3.39 ppb) and 234U/238U activity ratios (0.4-15.38) are observed. We conduct a first assessment in order to verify whether the results of our investigation support and complete previous hydrogeological and isotopic studies. The dissolved U content and 234U/238U activity ratio data were plotted on a two-dimensional diagram that was successfully utilized on sharing the CI aquifer into different compartments submitted to different oxidising/reducing conditions and leads also to distinguished two preferential flow paths in the Nefzaoua/Chott Fejej discharge area. Uranium isotopes disequilibrium indicate that ranium chemistry is mainly controlled by water-rock interaction enhanced by long residence time recognised for this aquifer.

Abstract  Lead and strontium isotope ratios were used for the origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. A simple and low-background sample preparation method was developed for the simultaneous separation of the analytes followed by the measurement of the isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The lead isotopic composition of the ore concentrates suggests applicability for the verification of the source of the nuclear material and by the use of the radiogenic Pb-207/Pb-206 ratio the age of the raw ore material can be calculated. However, during data interpretation, the relatively high variation of the lead isotopic composition within the mine site and the generally high contribution of natural lead as technological contamination have to be carefully taken into account. The Sr-87/Sr-86 isotope ratio is less prone to the variation within one mine site and less affected by the production process, thus it was found to be a more purposeful indicator for the origin assessment and source verification than the lead. The lead and strontium isotope ratios measured and the methodology developed provide information on the initial raw uranium ore used, and thus they can be used for source attribution of the uranium ore concentrates.

Abstract  Abstract: There is increasing interest in the role of brain cholesterol in Alzheimer's disease and the contribution of cholesterol to the formation of amyloid plaques. This paper presents a TEM study showing the binding of soluble ∼10nm diameter cholesterol-PEG 600 micelles to amyloid-β1-42 (Aβ1-42) fibrils formed either in the presence of this cholesterol derivative or to preformed fibrils generated under four different fibrillogenesis conditions. Specimens negatively stained with uranyl acetate revealed that during 24h fibrillogenesis at 37°C the cholesterol-PEG micelles bound periodically to Aβ1-42 protofibrils and apparently also formed a thin smooth unbroken coating on mature double helical fibrils. Preformed protofibrils, generated in water alone or in the presence of 0.1mM cupric sulphate, also exhibited periodic binding of cholesterol-PEG micelles, indicating the inherently helical nature of the protofibril. Double helical mature Aβ1-42 fibrils, generated in the presence of cholesterol microcrystals or hydrogen peroxide (1mM), bound cholesterol-PEG micelles with no immediately apparent regularity and without creating a smooth coating. The differing capacities of the Aβ1-42 protofibrils and mature double helical fibrils to bind cholesterol-PEG 600 may indicate differences in the accessibility of the micellar cholesterol to the purported Aβ17-21 hydrophobic cholesterol-binding motif on the fibril surfaces. [Copyright 2008 Elsevier] Copyright of Micron is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)

Abstract  This study analyses the effect of a specific kind of soil development, podzolisation, on selected radionuclide concentrations and the derived dose rates. 100 samples from four sandy, podzolised regions in Jutland, Denmark, were dated by luminescence dating. Dose rates were determined by gamma spectrometry. Of the 100 samples, 31 were retrieved from three profiles intersecting soil horizons affected by podzolisation. At 35 locations, additional material was collected for supplementary geochemical analyses (soil pH, organic carbon content and extractable iron and aluminium). The geochemical data and grain size data were correlated with radionuclide activity concentrations. These correlations do not indicate any significant relationship between organic carbon or extractable iron/aluminium and radionuclide concentrations; this suggests that the radionuclides are mainly internally bound in primary minerals, unlike the extractable iron, which is generally associated with surface coatings. We conclude that the radionuclide distribution in these young sandy soils has been relatively unaffected by the podzolisation process. Thus it appears that the dose rate at these sites is unlikely to have changed significantly with time as a result of podzolisation, because the parent material is relatively unweathered and the activity is dominated by internally bound radionuclides. [ABSTRACT FROM AUTHOR] Copyright of Geochronometria: Journal on Methods & Applications of Absolute Chronology is the property of Geochronometria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)

Abstract  The objectives of this study were to compare the effects of technetium and uranium on the yield and uptake, and to identify the organ of accumulation, of an edible leafy vegetable growing in sandy and peaty soils. In sand, where the soil's sorption capacity is negligible, technetium uptake is four orders of magnitude higher than from peat, suggesting no plant mediation of uptake and thus a constant concentration factor (>50) in an oxidizing environment where technetium is continuously supplied. The technetium is predominantly translocated to the shoots. When soil fixation occurs, as in peat, this becomes the controlling factor in the plant uptake of technetium. In the case of uranium, plant mediation is more significant. Uranium uptake by Swiss chard is up to 80 times higher from sand than from peat. The uranium is restricted to the root system and may only be precipitated on the outer root membrane and may not accumulate in the roots.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Trace elements can have profound adverse effects on the health of people burning coal in homes or living near coal deposits, coal mines, and coal-burning power plants. Trace elements such as arsenic emitted from coal-burning power plants in Europe and Asia have been shown to cause severe health problems. Perhaps the most widespread health problems are caused by domestic coal combustion in developing countries where millions of people suffer from fluorosis and thousands from arsenism. Better know ally toxic trace metals during coal cleaning, combustion, weathering, and leaching.

Abstract  Electron donor amendment for bioremediation often results in precipitation of secondary minerals and the growth of biomass, both of which can potentially change flow paths and the efficacy of bioremediation. Quantitative estimation of precipitate and biomass distribution has remained challenging, partly due to the intrinsic heterogeneities of natural porous media and the scarcity of field data. In this work, we examine the effects of physical and geochemical heterogeneities on the spatial distributions of mineral precipitates and biomass accumulated during a biostimulation field experiment near Rifle, Colorado. Field bromide breakthrough data were used to infer a heterogeneous distribution of hydraulic conductivity through inverse transport modeling, while the solid phase Fe(III) content was determined by assuming a negative correlation with hydraulic conductivity. Validated by field aqueous geochemical data, reactive transport modeling was used to explicitly keep track of the growth of the biomass and to estimate the spatial distribution of precipitates and biomass. The results show that the maximum mineral precipitation and biomass accumulation occurs in the vicinity of the injection wells, occupying up to 5.4vol.% of the pore space, and is dominated by reaction products of sulfate reduction. Accumulation near the injection wells is not strongly affected by heterogeneities present in the system due to the ubiquitous presence of sulfate in the groundwater. However, accumulation in the down-gradient regions is dominated by the iron-reducing reaction products, whose spatial patterns are strongly controlled by both physical and geochemical heterogeneities. Heterogeneities can lead to localized large accumulation of mineral precipitates and biomass, increasing the possibility of pore clogging. Although ignoring the heterogeneities of the system can lead to adequate prediction of the average behavior of sulfate-reducing related products, it can also lead to an overestimation of the overall accumulation of iron-reducing bacteria, as well as the rate and extent of iron reduction. Surprisingly, the model predicts that the total amount of uranium being reduced in the heterogeneous 2D system was similar to that in the 1D homogeneous system, suggesting that the overall uranium bioremediation efficacy may not be significantly affected by the heterogeneities of Fe(III) content in the down-gradient regions. Rather, the characteristics close to the vicinity of the injection wells might be crucial in determining the overall efficacy of uranium bioremediation. These findings have important implications not only for uranium bioremediation at the Rifle site and for bioremediation of other redox sensitive contaminants at sites with similar characteristics, but also for the development of optimal amendment delivery strategies in other settings.

Abstract  The radioactivity in tobacco leaves collected from 15 different regions of Greece before cigarette production was studied in order to estimate the effective dose from cigarette tobacco due to the naturally occurring primordial radionuclides, such as (226)Ra and (210)Pb of the uranium series and (228)Ra of the thorium series and or man-made radionuclides, such as (137)Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the annual effective dose due to inhalation for adults (smokers) for (226)Ra varied from 42.5 to 178.6 microSv y(-1) (average 79.7 microSv y(-1)), while for (228)Ra from 19.3 to 116.0 microSv y(-1) (average 67.1 microSv y(-1)) and for (210)Pb from 47.0 to 134.9 microSv y(-1) (average 104.7 microSv y(-1)), that is the same order of magnitude for each radionuclide. The sum of the effective doses of the three natural radionuclides varied from 151.9 to 401.3 microSv y(-1) (average 251.5 microSv y(-1)). The annual effective dose from (137)Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv y(-1) (average 199.3 nSv y(-1)).

Abstract  Natural radioactivity in drinking water was determined in population-based random study of 472 private wells. The mean concentrations of 222Rn, 226Ra, 234U, 238U, 210Pb and 210Po in drilled wells were 460, 0.05, 0.35, 0.26, 0.04 and 0.05 Bq l-1, and in wells dug in the soil were 50, 0.016, 0.02, 0.015, 0.013 and 0.007 Bq l-1, respectively. Approximately 10% of the drilled wells exceeded a radon concentration of 1000 Bq l-1 and 18% a uranium concentration of 15 µg l-1. The mean annual effective dose from natural radionuclides for a drilled well user was 0.4 mSv and 0.05 mSv for a user of a well dug in the soil. The effective dose arising from 222Rn was 75% of the total of all natural radionuclides for drilled well users. As regards long-lived radionuclides, 210Po and 210Pb caused the largest portion of the effective dose. The dose arising from 238U, 234U and 226Ra was only 8% of the total of all natural radionuclides.

Abstract  In summary, the EPA has begun to look critically at the induction of certain types of tumors in certain species, including liver tumors in mice. The controversy over the use of such tumor data in assessing the cancer risk for humans has been going on for some time. The present agency policy is to downgrade the weight of evidence for such data under certain conditions. Review of the cancer risk assessments for the 109 chemicals that the agency has formally verified shows that a variety of chemicals yield liver tumors in mice. However, one group of substances that consistently produced such tumors was chlorinated compounds (84%). Many of these compounds not only induced liver tumors in mice but also induced liver tumors in rats and/or other types of tumors in mice and rats. However, several of the chlorinated compounds produced only mouse liver tumors. Another group of compounds that often induced liver tumors in mice was nitrogen-containing compounds (aromatic amines, hydrazines, nitrosamines). These latter substances tended to not only induce liver tumors in mice but also a variety of other tumor types in a variety of species. Mouse liver tumor data have played a major role in the classification of substances in categories B2 and C. Fifty-six percent of the chemicals in category B2 and 40% in category C were classified based at least partially on the use of mouse liver tumor data. In addition, 21 of the 29 category B2 chemicals that produced liver tumors in mice and 5 of the 8 category C chemicals are chlorinated compounds. These two results indicate the importance of chlorinated compounds to the agency, and therefore, the importance of mouse liver tumor data in agency cancer risk assessments.

Abstract  In order to develop more realistic risk assessments, an experimental program was conducted to characterize indoor, residential environments and the relationship between the indoor environment and contaminants that originated from the outdoor environment. Parameters measured included concentration of uranium in soils, mass loading of dust on indoor surfaces, and concentrations of uranium in indoor dust. Samples of indoor dust were collected using a personal air sampler modified to act as a low flow rate vacuum cleaner. The concentrations of uranium in indoor dust were measured using kinetic phosphorescence analysis, while the concentrations of uranium in outdoor soil were measured by analyzing the thorium-234 activity using gamma-ray spectrometry. This pilot study derived an estimate of 20 to 30% of indoor contamination resulting from sources in soil.

Abstract  This paper discusses current information on the biological behavior of americium and describes a biokinetic model for americium in humans. Emphasis is on the timedependent distribution and excretion of systemic americium in the adult, but potential differences with age in parameter values are addressed, and predictive models of absorption of americium to blood from the respiratory and gastrointestinal (GI) tracts are provided in an appendix. The analysis builds on the author's previous biokinetic model for plutonium in humans and recent analyses and/or models of other authors regarding the behavior of americium and related elements in humans and laboratory animals. Compared with the retention model for americium implied in ICRP Publication No. 48, the present model, as applied to adults, yields reasonably similar whole-body retention of americium at all times, much less retention in the liver after a few months, somewhat greater retention in the total skeleton after a few years, and very similar long-term integrated activities of long-lived americium isotopes on bone surfaces. Compared with a previous model of Durbin and Schmidt, the present model, as applied to adults, predicts very similar retention in the liver at all times, somewhat smaller retention in the total skeleton after a few years, and somewhat greater urinary excretion rates at all times after acute uptake to blood.

Abstract  Starting from a cross-sectional survey in 1973, the mortality of two cohorts of Sardinian metal miners was followed through December 31, 1988. In mine A, the quartz concentration in respirable dust ranged between 0.2% and 2.0% and the exposure to radon daughters averaged 0.13 working level (WL), with the highest estimated cumulative exposure around 80-120 WLM. In mine B, the silica content was much higher (6.5-29%), but exposure to radon daughters was significantly lower than in mine A. More than 98% of the overall work force in 1973 (1,741 miners) entered the cohort, providing 25,842.5 person-years. Smoking, occupational history, chest radiographs, and lung function tests were available for the cohort members at admission. Mortality for all causes was slightly lower than expected. A significant excess for nonmalignant chronic respiratory diseases was noticed in both mines. Twenty-four subjects died of lung cancer, 17 from mine A (SMR: 128; 95% confidence interval [CI]: 75-205) and 7 from mine B (SMR: 85; 95% CI: 34-175). The SMR for lung cancer was highest among the underground workers from mine A (SMR: 148; 95% CI: 74-265), with a significant upward trend by duration of employment in underground jobs. Mine B underground miners showed lung cancer SMRs close to 100 without a significant trend by duration of employment. Among underground miners with spirometric airways obstruction in 1973, those from mine A showed the highest risk (SMR: 316; 95% CI: 116-687). The relationship did not change after adjusting for age and smoking. Based on the present findings, crystalline silica per se does not appear to affect lung cancer mortality. A slight association between lung cancer mortality and exposure to radon daughters, though within relatively low levels, may be considered for underground miners from mine A. Impaired pulmonary function may be an independent predictor of lung cancer and an important risk factor enhancing the residence time of inhaled carcinogens, i.e., alpha particles or PAHs, by impairing their bronchial and alveolar clearance.

Abstract  The distribution of inhaled UO2 particles is described in the upper respiratory tract of rats up to 14 d after inhalation. Delayed neutron analysis was used to determine accurately nanogram quantities of UO2 present in excised tissues. The mass of UO2 in the extrapulmonary bronchi and first bifurcation decreased more slowly over 0--8 d after inhalation than the corresponding mass on the trachea. Between 8 and 14 d neither amount altered significantly. Small but significant quantities of UO2 deposited on the trachea during inhalation, remained until at least 14 d after inhalation.

Abstract  Following the incident of acidic pollution of water by aluminium sulfate centred around Camelford in July 1988, we have carried out a retrospective analysis of the mobilization of toxic metals to residents of the area. An advanced nuclear technique was used to measure trace levels of elements within hair, thus, avoiding surface contamination. In contrast to controls, lead, but no other toxic metals, was consistently found within sections of hair that dated to mid-1988 from four residents; they must, therefore, have consumed this metal around the time of the incident. The source of this lead was probably local water pipe residue, and this was found on analysis to have a matrix specific to such soft-water areas that, prior to the incident, had slowly accumulated certain toxic metals such as cadmium and uranium and particularly lead. Lead is mobilized from such residues by acidic water and could, therefore, have heavily contaminated mains water after the incident. However, analyses of residents' plasma and whole blood, and of urine following a lead-chelation test, showed no evidence of either long-term increased body burdens of toxic metals or depletion of essential elements. In addition, we found no evidence of continued poor water quality in the area. In conclusion, during a short period following the pollution, some residents who consumed mains water would have been acutely exposed to lead and other toxic metals. Prediction of the scale of metal exposure to individuals was not possible owing to heterogeneity of the water distribution network, but long-term effects to residents from lead are not anticipated.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract  Capillary zone electrophoresis was used to study the uranyl and short chain carboxylic acid sorption on silica and rutile. The separation and the simultaneous determination (in a single run) of a number of short chain carboxylic acids (oxalic, formic, acetic and propionic) and U(VI) with direct UV detection is developed for the analysis of solutions after the sorption experiments. The reverse polarity mode is used (the injection is performed at the negative end). The matrix effect of Si(IV) (possible silica dissolution product) and perchlorate (added for constant ionic strength in sorption experiments) on the separation of U(VI) and organic acids is investigated. The influence of methanol addition in carrier electrolyte on the separation selectivity of given analytes is also studied. Under the chosen conditions (carbonate buffer (ionic strength of 0.1M), pH 9.8, 0.15 mM of tetradecyltrimethylammonium bromide, 25% (v/v) of methanol) the calibration curves are plotted. They are linear in two ranges of concentration from ∼1×10(-5) to ∼1×10(-3) M for oxalate, acetate, propionate, U(VI) and ∼1×10(-4) to ∼1×10(-3) for formate. The accuracy of the procedure is checked by the "added-found" method in simulation solutions. The relative standard deviations of the concentrations found are within the range of 1-10% and the recovery is in the range of 90-115%. This method is applied for the analysis of aqueous samples issued from sorption experiments on silica and rutile. The obtained results indicate that the given organic acids decrease uranium sorption both on silica and rutile. These experiments demonstrate that short chain carboxylic acids can influence the mobility and the chemistry of U(VI) in the environment.

Abstract  In the crystal structure of the title compound, [U(2)(NO(3))(2)O(4)(O(2))(C(4)H(7)NO)(4)], two UO(2) (2+) ions are connected by a μ-η(2):η(2)-O(2) unit. The O(2) unit shows 'side-on' coordination to both U atoms. An inversion center is located at the midpoint of the O-O bond in the O(2) unit, affording a centrosymmetrically expanded dimeric structure. The U-O(axial) bond lengths are 1.777 (4) Å and 1.784 (4) Å, indicating that the oxidation state of U is exclusively 6+, i.e., UO(2) (2+). Furthermore, the O-O distance is 1.492 (8) Å, which is typical of peroxide, O(2) (2-). The U atom is eight-coordinated in a hexa-gonal-bipyramidal geometry. The coordinating atoms of the nitrate and pyrrolidine-2-one ligands and the μ-η(2):η(2)-O(2) (2-) unit are located in the equatorial plane and form an irregular hexa-gon. An inter-molecular hydrogen bond is found between N-H of the pyrrolidine-2-one ligand and the coordinating O of the same ligand in a neighboring complex. A second inter-molecular hydrogen bond is found between the N-H of the other pyrrolidine-2-one ligand and one of the uranyl oxido atoms.

Abstract  We examined the effects of chronic exposure to radionuclides, primarily uranium and mixed-fission products, on cancer mortality in a retrospective cohort study of workers enrolled in the radiation-monitoring program of a nuclear research and development facility. Between 1950 and 1994, 2,297 workers were monitored for internal radiation exposures, and 441 workers died, 134 (30.4%) of them from cancer as the underlying cause. We calculated internal lung-dose estimates based on urinalysis and whole-body and lung counts reported for individual workers. We examined cancer mortality of workers exposed at different cumulative lung-dose levels using complete risk-set analysis for cohort data, adjusting for age, pay type, time since first radiation monitored, and external radiation. In addition, we examined the potential for confounding due to chemical exposures and smoking, explored whether external radiation exposure modifies the effects of internal exposure, and estimated effects after excluding exposures likely to have been unrelated to disease onset. Dose-response relations were observed for death from hemato- and lymphopoietic cancers and from upper aerodigestive tract cancers, adjusting for age, time since first monitored, pay type, and external (gamma) radiation dose. No association was found for other cancers, including cancers of the lung. Despite the small number of exposed deaths from specific cancer types and possible bias due to measurement error and confounding, the positive findings and strong dose-response gradients observed suggest carcinogenic effects of internal radiation to the upper aerodigestive tract and the blood and lymph system in this occupational cohort. However, causal inferences require replication of our results in other populations or confirmation with an extended follow-up of this cohort.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM CONSENSUS ON SYNERGISM BETWEEN CIGARETTE SMOKE AND OTHER ENVIRONMENTAL CARCINOGENS IN THE CAUSATION OF LUNG CANCERYBOOK CHAPTER LITERATURE REVIEW HUMAN PATIENT ONCOLOGY LUNG CANCER CIGARETTE SMOKE RADON INTERACTION ENVIRONMENTAL CARCINOGEN SYNERGISM CARCINOGEN ASBESTOS INTERACTION ALCOHOL INTERACTION RESPIRATORY SYSTEM DISEASE CAUSATION NEOPLASTIC DISEASE

Abstract  Many pyrotechnic devices contain barium nitrate which is used as an oxidizer and colouring agent primarily for green-coloured fireworks. Similarly, strontium nitrate is used for red-coloured pyrotechnic effects. Due to their chemical similarities to radium, barium and strontium ores can accumulate radium, causing a remarkable activity in these minerals. Radium in such contaminated raw materials can be processed together with the barium or strontium, unless extensive purification of the ores was undertaken. For example, the utilization of 'radiobarite' for the production of pyrotechnic ingredients can therefore cause atmospheric pollution with radium aerosols when the firework is displayed, resulting in negative health effects upon inhalation of these aerosols. In this study, we investigated the occurrence of gamma-photon-emitting radionuclides in several pyrotechnic devices. The highest specific activities were due to K-40 (up to 20 Bq g(-1), average value 14 Bq g(-1)). Radium-226 activities were in the range of 16-260 mBq g(-1) (average value 81 mBq g(-1)). Since no uranium was found in any of the samples, indeed, a slight enrichment of Ra-226 in coloured pyrotechnics can be observed. Radioactive impurities stemming from the Th-232 decay chain were found in many samples as well. In the course of novel developments aiming at the 'greening' of pyrotechnics, the potential radioactive hazard should be considered as well.

Abstract  An inductively coupled plasma source was coupled to a magnetic sector mass analyser equipped with seven Faraday detectors. An electrostatic filter located between the plasma source and the magnetic sector was used to create a double focusing system. Isotopic ratio measurements of uranium and lead standards revealed levels of internal and external precision comparable to those obtained using thermal ionization mass spectrometry. An external precision [relative standard deviation (RSD)] of 0.014% was obtained from the 235U:238U measurement of six samples of a National Bureau of Standards (NBS)[now National Institute of Standards and Technology (NIST)] Standard Reference Material (SRM) U-500, while an RSD of 0.022% was obtained from the 206Pb:204Pb measurement of six samples of NBS SRM Pb-981. Measured isotopic ratios deviated from the NBS value by approximately 0.9% per atomic mass unit. This deviation approximates to a linear function of mass bias and can therefore be corrected for by the analysis of standards. The analysis of NBS SRM Sr-987 revealed superior levels of internal and external precision. The normalization of the 87Sr:86Sr ratio to the 86Sr:88Sr ratio reduced the RSD to approximately 0.008%. The measured ratio was within 0.01% of the NBS value and the day-to-day reproducibility was consistent within one standard deviation.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The use of fertilizers and soil amendments has raised concern regarding the toxic accumulation of their trace components in the environment. The objective of this research was to evaluate the trace element and heavy metal composition of a wide variety of fertilizers and soil amendments. Thirty-five elements, including priority pollutants, were determined in 24 materials. A microwave HNO3-HF-H2O2-H3BO3 digestion procedure was used to dissolve the samples. Selected solid samples were directly analyzed by neutron activation analysis, while atomic absorption and inductively-coupled plasma atomic emission spectrometric determinations were carried out on the digests. The trace element and heavy metal concentrations generally decreased in the following sample order: rock phosphate > sewage sludge > phosphorus fertilizer > organic amendments and liming materials > K fertilizers the sewage sludge

Abstract  The concentrations of uranium, thorium, barium, nickel, strontium and lead in the samples of the tailings and plant species collected from a uranium mill tailings repository in South China were analyzed. Then, the removal capability of a plant for a target element was assessed. It was found that Phragmites australis had the greatest removal capabilities for uranium (820 μg), thorium (103 μg) and lead (1,870 μg). Miscanthus floridulus had the greatest removal capabilities for barium (3,730 μg) and nickel (667 μg), and Parthenocissus quinquefolia had the greatest removal capability for strontium (3,920 μg). In this study, a novel coefficient, termed as phytoremediation factor (PF), was proposed, for the first time, to assess the potential of a plant to be used in phytoremediation of a target element contaminated soil. Phragmites australis has the highest PFs for uranium (16.6), thorium (8.68), barium (10.0) and lead (10.5). Miscanthus floridulus has the highest PF for Ni (25.0). Broussonetia papyrifera and Parthenocissus quinquefolia have the relatively high PFs for strontium (28.1 and 25.4, respectively). On the basis of the definition for a hyperaccumulator, only Cyperus iria and Parthenocissus quinquefolia satisfied the criteria for hyperaccumulator of uranium (36.4 μg/g) and strontium (190 μg/g), and could be the candidates for phytoremediation of uranium and strontium contaminated soils. The results show that the PF has advantage over the hyperaccumulator in reflecting the removal capabilities of a plant for a target element, and is more adequate for assessing the potential of a plant to be used in phytoremediation than conventional method.

Abstract  Concentrations of 48 elements in the ground growing mosses Hylocomium splendens and Pleurozium schreberi have been compared with wet deposition data for the same elements at 13 Norwegian sites. Significant positive correlations were found for V, Fe, Co, As, Y, Mo, Cd, Sb, Ce, Sm, Er, Tl and Pb in Hylocomium splendens, and for Mg, V, Fe, Co, As, Se, Y, Mo, Cd, Sb, Tl and Pb in Pleurozium schreberi. Regression equations for transforming moss concentration data to absolute deposition rates have been calculated for those of the above elements which are of interest from a pollution point of view. The concentration levels of Li, Be, Mg, Ca, Zn, Ge, As, Se, Sr, Y, Zr, Sn, Cs, Ba, La, Ce, Pr, Nd, Sm, Ho, Yb, Hf, Ta and U were similar in the two moss species. Hylocomium splendens had highest concentrations of Cr, Fe, Co, Ni, Cu, Ga, Nb, Mo, Sb, Eu, Gd, Tb, Dy, Er, Tm, Lu, W, Tl, Pb and Th, whereas V, Mn, Rb and Cd were highest in Pleurozium schreberi. No variations were observed in the concentrations of the studied elements during the sampling season.

Abstract  Abstract The aim of this work was to assess the relationships between lead (Pb) and uranium (U) exposure, lipid peroxidation and some enzyme activities in a mollusc (Cohicula sp.), an earthworm (Eisenia fetida) and a fish (Brachydanio redo). A comparative shrdy was perfotmed both in vibo and in vivo on whole organism postmitochondrial fractions and four potential biomarken were analyted: a marker of neurotoxicity (acetylcholinesterase activity, AChE, EC 3.1.1.7), a marker of oxidative sbss (malondialdehyde (MDA) level), and two markers of hydroperoxide detoxication: catalase (EC 1.11.1.6) and glutathione pemxidase (GPx, EC 1.11.1.9) activities. Our results have shown that the MDA contents were not signilicantty changed by exposures to lead either in vitro or in vivo. During uranium exposure, the MDA content was increased in vitro (particularly in fish samples) whereas this metal failed to sthnulate Spid peroxidation in vivo. With some exceptions, in vitro and in vivo exposures to lead and uranium showed that the AChE, catalase and GPx acbirites were decreased in the three species. These exceptions indicated that different mechanisms occurred in the different species. In conclusion, it was shown that S9 fractions of whole organisms could be useful for environmental contamination biomonitoring. Moreover, it was shown that AChE activities wen modulated by metals in viva and cannot be considered as specific bomarken of organophosphorus or carbaw pedcide exposure. Acetylcholinesterase and catalase activieies cwld be used to survey lead and uranium contamination.