Status of trace and toxic elements pollution in creek ecosystem using TXRF method

The economic development worldwide has brought in its wake many changes in the environment. Marine ecosystem which forms a part of this environment has been subjected to impact of industrialisation and urbanization. The study has been carried out in the creek ecosystem of Mumbai receiving the effluents from industrial and urban settlements. The trace elements such as P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb, As, Rb and Sr were analysed in the creek water collected from the side receiving industrial effluent and discharges from the urban settlements using total reflection X-ray fluorescence spectrometry. On comparing the concentration of the trace element from the mid stream water of the creek with the water samples collected from the industrial and city effluent receiving side, it was found that the concentration of P, Ca, Mn, Fe, Co, Cu, Zn, Pb and As were found higher in the industrial side of the creek whereas V, Cr and Ni concentration were found higher in the samples collected from the side receiving city effluent.     

Distribution of uranium in human lungs

Several human lung samples were dissected into lobes and uranium and silicon contents in each lobe were determined by the fission track method and the inductively coupled plasma-atomic emission spectrometry (ICP-AES), respectively. It was found that both uranium and silicon concentrations were high in the upper lobe compared with those in the lower one. Though the tendency may be mainly interpreted by the deposition way of airborne dust in the lung, the higher U/Si concentration ratio in the upper part than that in the lower part of lungs may suggest the partial removal of uranium deposited in the lower part of the tissue.     

Distribution of uranium in human bones

Uranium and calcium contents in human bones (skull, rib and femur) were determined by the fission track method and the inductively coupled plasma-atomic emission spectroscopic method (ICP-AES), respectively. The U/Ca concentration ratio in the bones was found to decrease in the order of rib greater than femur greater than skull, which is in accordance with the decreasing order of the mean annual replacement percentage of bone components. Several femur bones were cut into several longitudinal segments, and uranium and calcium contents in each segment were determined. Among these, the U/Ca ratio in the epiphysis was higher than those in the diaphysis.     

Studies on processes for recovering uranium from sediment wastes

Journal of Radioanalytical and Nuclear Chemistry - Sediment wastes generated from nuclear facilities often contain uranium and iron. From the viewpoint of reduction of environmental impact,...     

Distribution of uranium and thorium in fractionated sediment samples obtained from different locations across Thane Creek area (Mumbai,India)

Uranium concentration varies from 9.01 to 12.7, 8.03 to 11.5, 9.1 to 14.0 and 10.1 to 14.2 mg/kg in grab sediment, coarse sand fraction, fine sand fraction, silt and clay fraction respectively. Thorium concentration varies from 20.0 to 29.4, 17.3 to 28.6, 19.6 to 30.4 and 21.1 to 35.9 in grab sediment, coarse sand fraction, fine sand fraction, silt and clay fraction respectively. Uranium and thorium concentrations vary in different size fractionated sediment samples like silt and clay fraction > fine sand fraction > coarse sand fraction.     

Radiochemical analysis of uranium isotopes in soil and sediment samples with extraction chromatography

An accurate and simple analytical technique for uranium isotopes in highly contaminated soil samples was developed and validated by application to IAEA-Reference samples and environmental samples. For overcoming the demerits of the TBP extraction method, sample materials were decomposited with HNO(3) and HF and uranium isotopes were purified with an anion exchange resin and a TRU Spec resin. With the extraction chromatography method, hindrance elements were completely removed from the uranium fraction. The chemical yields with the extraction chromatography method were <10% higher than those with the TBP extraction method. The concentrations of uranium isotopes using the extraction chromatography method were consistent with the reference values reported by the IAEA.     

Distribution of Cd and Pb in a wetland ecosystem

Cadmium and lead contents in sediments, dominant species of plants (Phargmites aus-tralis and Scripus mariquter), benthos (Helice tridens tientsinensis, llyoplax deschampsi, and Bul-lacta exarata), and waders (Calidris ruficollis) on the Eastern End of Chongming Island were measured. The results showed that, for cadmium, there are clear stratification in the sediment of reclaimed area and bio-amplification in food chain. However, for lead, a phenomenon was different. The amplification factors (AFs) for cadmium of primary producers, primary consumers, and secondary consumers were 2.59-12.38, 0.09-8.44, and 51.1, respectively. For lead, AFs of primary producers, primary consumers and the top trophic layer were 0.29-2.62, 0.06-5.62, and 7.31, respectively. Each species of macrobenthos showed different strategies to cadmium and lead. Large-sized crabs accumulated more lead, while small-sized crabs and snails accumulated more cadmium. Waders had significantly highest AFs for cadmium and lead in the study. Tha     

Determination of uranium in pore water from coastal sediment by standard addition ICP-MS analysis

Mass spectrometry using ICP-MS was applied to determine the uranium content in pore water samples through the standard addition method. This method requires less than 0.2 ml of a water sample, without any chemical separation. The sample solution (50 mg) was diluted with ∼1% HNO₃ to make a total weight of 5.00 g, after the addition of uranium standard. The method introduced 1% of analytical precision for measured uranium in the samples. This rapid and simple technique allows multi-trace elemental quantification using mixed standards. The behavior of uranium in pore water and the variations of uranium content at different depths of pore water are discussed.     

The transfer of uranium from sediment to water along Jucar River, Spain

The effect of sediment size, pH, temperature and conductivity on the transfer of uranium from sediment to water has been studied. The uranium concentration and the²³⁴U/²³⁸U,²³⁵U/²³⁸U activity ratios were measured in water, sediments and suspended matter sampled from Jucar River, using low level alpha-spectrometry. Distribution factors were obtained from these measurements. A more detailed sampling was done in the neighbourhood of the Cofrentes Nuclear Plant (Valencia, Spain). Total uranium activity,²³⁴U/²³⁸U activity ratio and distribution factors for²³⁴U and²³⁸U were found to vary with pH. Leaching and dilution, which depend on pH and salinity, are the probable mechanisms for these changes.     

Distribution of uranium at Mumbai Harbour Bay (MHB)

Mumbai Harbour Bay (MHB) is a recipient of low level treated effluents from BARC, Trombay. In addition, the Bay is also a recipient of domestic and industrial wastes from the city of Mumbai and adjoining areas. The average value of uranium concentration reported for Indian Bay water at Tarapur and Mumbai is ~3.0 ppb which is comparable with the reported value for Arabian sea. As such the global average is reported to be ~3.3 ppb by Oceanologists. The present study deals with the distribution of uranium in seawater of MHB. The uranium activity in MHB by alpha spectrometry was found to be between 1.0 and 4.4 ppb with an average concentration of 2.5 ppb which is comparable with the earlier reported average activity of 2.6 ppb in the MHB as well as those reported globally. To compare the results obtained by alpha spectrometry, uranium estimation was also carried out using Laser fluorimeter and the levels of uranium concentration have ranged between 0.8 and 4.9 ppb with an average concentration of 2.7 ppb.     

Distribution of environmental radionuclides in sediment cores of the Jinheung catchment

Sediment core samples taken from the Jinheung catchment located in the middle of the Korean Peninsula were used to know environmental radionuclide distribution. The grain sizes of the sediment cores were found at depth of about 17 cm suggesting that it might have occurred during a dry period of 1969. The radionuclides, ¹³⁷Cs, ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, ²³⁴U, ²³⁸U, ²²⁸Th, ²³⁰Th, ²³²Th, were analyzed by sector type ICP-MS and gamma-spectrometry. The Cs and Pu distribution changed with the depth, in which the maximum ranged from 14 to 22 cm. This was due to the high activity of the results of nuclear bomb tests in the air from 1960s and showed different distribution pattern on the soil surface. The average activity ratio of ²⁴⁰Pu/²³⁹Pu and ²³⁷Np/²³⁹Pu was 0.173 and 0.45, respectively. These values were similar to the north hemisphere global fallout ratio of ²⁴⁰Pu/²³⁹Pu (0.18) and ²³⁷Np/²³⁹Pu (0.45). The ²³⁷Np/²³⁹Pu ratio showed a higher value than the global fallout ratio above 14 cm depth. The U, Th and their daughter radionuclides kept secular equilibrium in the sediment core because the average activity ratios were nearly 1.     

Voltammetric determination of uranium in rocks, soils and sediment by using the catalytic nitrate reduction

The differential pulse voltammetry with a hanging drop mercury electrode using catalytic reduction was used to determine uranium at trace level in rocks, soils and sediments. Some the instrumental parameters were established at optimal conditions. A softer digestion than the normal high pressure method was applied to dissolve the samples. A liquid liquid extraction procedure was used to separate the uranium from matrices. The precision and accuracy of method were evaluated, using certified Soil-7, 312 and 314 samples from IAEA which uranium concentrations lie from 2 to 60g/g. The results are in good agreement with those obtained from other techniques and reference materials.     

Determination of uranium in marine sediment pore waters by isotope dilution inductively coupled plasma mass spectrometry

Inductively coupled plasma mass spectrometry (ICP-MS) was used in an isotope dilution mode to assay small-volume (0.25 ml) sediment pore waters for their uranium contents, using ²³⁶U as the spike. The only pretreatment required was a simple dilution by a factor of 20, which gave sufficient volume for three replicate analyses per sample. Rapid and accurate results were obtained for a variety of samples and standards, ranging in concentration from 0.05 to 10 ng U ml^?1. A suite of 30 samples can be analysed in less than 6 h by this method. The relative standard deviation was better than 1.9%, with a detection limit, based on 3σ background, of 2 pg U ml^?1 in solution (40 pg ml^?1 in samples). Sea water is a difficult matrix for ICP-MS and thus the method is generally suitable for uranium determinations in many other sample solutions.     

Distribution and mean residence time of natural radionuclides in the forest ecosystem

Activity concentrations of radionuclides,⁷Be,²¹⁰Pb and²¹⁰Po, in precipitation (rain, throughfall and stemflow), wood and soil were determined by using gamma-ray and alpha-ray spectrometry to estimate the migration behavior of these radionuclides in the forest canopy. The activity ratios between output and input precipitations for the forest canopy were 0.53 of⁷Be, 0.79 of²¹⁰Pb and 1.5 of²¹⁰Po for Pasania edulis forest. A dynamic model of the transport and fate of radionuclides in the forest ecosystem was constructed. Mean residence times of radionuclides were 56 days for⁷Be, 765 days for²¹⁰Pb and 653 days for²¹⁰Po for Pasania edulis forest.     

Determination of naturally occurring uranium concentrations in seawater,sediment, and marine organisms in Japanese estuarine areas

For safety assessments of geological repositories of nuclear waste, understanding of uranium (U) fate in estuarine areas is important because U chemical behavior in the areas is expected to be complex. Environmental transfer parameters such as sediment–water distribution coefficients (K _d) and concentration ratios (CRs) for marine organisms are useful in mathematical models for the assessment. However, due to its low concentration in estuarine water, K _d and CF data for U are scarce. Thus we studied a rapid method for separation and concentration of U from estuarine water samples using NOBIAS-CHELATE PA1 resin columns followed by inductively coupled plasma mass spectrometry (ICP-MS) for U measurement. Chemical recovery was about 100% at pH of 5.7 ± 0.1 from the water samples and alkali and alkaline earth metals were removed. The method was used to measure U concentrations in estuarine water samples collected at eight Japanese estuarine areas; they ranged from 0.1 to 3.8 μg L⁻¹. We also measured U concentrations in sediment and marine organism samples by ICP-MS after acid digestion. Using these values, we observed K _d (range: 39–284 L kg⁻¹) and CRs (0.86–52 L kg⁻¹ for macroalgae, 0.087–15 L kg⁻¹ for crustaceans, and 0.52–93 L kg⁻¹ for molluscs).     

Concentration, distribution and characteristics of depleted uranium (DU) in the Kosovo ecosystem: A comparison with the uranium behavior in the environment uncontaminated by DU

The smear samples of the penetrator were analyzed for the determination of the uranium composition. The obtained relative composition (m/m) of uranium isotopes in all the smear samples is in the range of 99.76-99.78% for ²³⁸U, 0.000659-0.000696% for ²³⁴U, 0.213-0.234% for ²³⁵U, and 0.00274-0.00328% for ²³⁶U, showing characteristics of depleted uranium (DU). The uranium concentrations in Kosovo soil and water samples as well as biological samples were investigated. It was found that the uranium concentrations in the Kosovo soil samples are in the range of 11.3-2.26·10⁵ Bq·kg^-1 for ²³⁸U, 10.3-3.01·10⁴ Bq·kg^-1 for ²³⁴U, 0.60-3251 Bq·kg^-1 for ²³⁵U, and ￡0.019-1309 Bq·kg^-1 for ²³⁶U. The obtained activity ratios are in the range of 0.112-1.086 for ²³⁴U/²³⁸U, 0.0123-0.1144 for ²³⁵U/²³⁸U, and 0-0.0078 for ²³⁶U/²³⁸U, indicating the presence of DU in about 77% of the surface soil samples. At a specific site, the DU inventory in the surface soil is about 140 mg·cm^-2, which is 1.68·10⁶ times higher as the estimated mean DU dispersion rate in the region. The uranium concentrations in Kosovo lichen, mushroom, bark, etc., are in the range of 1.97-4.06·10⁴ Bq·kg^-1 for ²³⁸U, 0.48-5158 Bq·kg^-1 for ²³⁴U, 0.032-617 Bq·kg^-1 for ²³⁵U, and ￡0.019-235 Bq·kg^-1 for ²³⁶U with mean activity ratios of 0.325±0.0223 for ²³⁴U/²³⁸U, of 0.0238±0.0122 for ²³⁵U/²³⁸U, and 0.0034±0.0028 for +U/²³⁸U, indicating the presence of DU in the entire sample. On the contrary, the uranium concentrations in Kosovo water samples are low, compared with the water samples collected in central Italy, indicating the presence of negligible amount of DU. The uranium isotopes in Kosovo waters do not constitute a risk of health at the present time. This revised version was published online in July 2006 with corrections to the Cover Date.     

Determination of uranium in uranium hexafluoride material

A rapid and precise method has been developed for the determination of uranium in uranium hexafluoride material that contains essentially no non-volatile impurities. Approximately 7 g of uranium hexafluoride is transferred into a tared fluorothene tube, weighed, frozen, and hydrolyzed in 150 ml of ice-cold water in a platinum dish. The solution is evaporated to dryness, and the residue is ignited to urano-uranic oxide and weighed. The precision of a single analysis at the 95% confidence interval is ± 0.06% of the value, with no significant bias     

Distribution coefficient and redox behaviour of uranium in Authie Bay (northern France)

Some mechanistic aspects associated with uranium release/immobilization and sedimentation in Authie Bay are presented in the present work. For this purpose, U contents in estuarine oxic waters, porewaters and sediment solids are determined. These analytical data allow us to appraise the partitioning of this metal between the liquid phase and the particulate matter/sedimentary material by calculating its distribution coefficient. Our findings further reveal that the distribution coefficient varies significantly with depth probably in response to the microbial activities in these sediments. This is confirmed by our studies on the geochemical behaviour of Fe and Mn in Authie Bay sediments. Finally, studies on the thermodynamic characteristics of sedimentary U in Authie Bay are undertaken in order to select possible U water–mineral equilibria that could involve in this environment, and to help define conditions of sedimentary U bioreduction.     

Precise determination of uranium in pure uranium and uranium compounds by constant-current coulomeric titration

A procedure is described for very precise determination of uranium in high-purity uranium and uranium compounds. Uranium(VI) is reduced in a concentrated hydrochloric acid solution by metallic aluminium in the presence of cadmium ions to uranium(III). This is oxidized to uranium(IV) by protons on addition of an excess of orthophosphoric acid, and then oxidized to uranium(VI) by adding a weighed quantity of potassium dichromate in small excess. The excess of potassium dichromate is determined by constant-current coulometry. The coefficient of variation does not exceed 0.003%.     

Distribution of137Cs and239,240Pu in the sediment of the Seto Inland Sea

The contents and distribution patterns of¹³⁷Cs and^239,240Pu in the sediments of the Seto Inland Sea were determined. In most of the sediment columns, approximately uniform concentrations were found to a depth of around 20 cm, probably due to bioturbation. Total amounts of¹³⁷Cs in the sediment column are considerably lower than the global fallout inputs. It is suggested that a significant portion of¹³⁷Cs input was removed from the Seto Inland Sea to the open ocean. Large excess inventories of^239,240Pu over fallout input were observed in the investigated sediment columns.