Partial purification of neutron-activation 99Mo from cross-contaminant radionuclides onto potassium nickel hexacyanoferrate(II) column

Potassium nickel hexacyanoferrate(II) matrix was prepared and characterized. Purification of neutron-activation ⁹⁹Mo–molybdate(VI) solutes from some residual cross-contaminant radionuclides including ¹³⁴Cs, ⁸⁶Rb, ¹²⁴Sb, ⁶⁰Co and ⁵¹Cr was carried out onto small chromatographic columns of the matrix (each of 1.0 g). Gamma-ray spectrometric analysis data showed that the purification process was not affected by either Mo(VI) concentrations (0.13 and 0.02 M Mo) in the feeding solution of 3.5 M NaNO₃ at pH 9.5 or flow rates (0.2 and 5.0 mL/min) at room temperature. Molybdenum(VI) average loss onto the column matrix did not exceed 7.7 × 10^?2 mmol Mo. Except for ⁵¹Cr, the matrix has very high selectivity for ¹³⁴Cs, ⁸⁶Rb and ¹²⁴Sb with ~50% ⁶⁰Co elimination. The obtained data were briefly discussed.     

Cesium,manganese and cobalt water–sediment transfer kinetics and diffusion into mangrove sediments inferred by radiotracer experiments

A study on the trace elements transfer from tidal water to mangrove sediments from Guanabara Bay (southeastern Brazil) was performed in laboratory microcosms. Sediment cores were covered with tidal water spiked with ¹³⁷Cs, ⁵⁴Mn and ⁵⁷Co during 5-h experiments, and water samples were taken at regular intervals to measure uptake kinetics at the sediment–water interface. At the end of the experiments, the uptake and diffusional penetration into the sediments was evaluated. Half-removal times from water to sediments were slightly higher for ¹³⁷Cs (3.4 ± 1.7 h) than observed for ⁵⁴Mn (2.3 ± 0.2 h) and ⁵⁷Co (2.6 ± 1.1 h). After these experiments, all radioisotopes presented decreasing activities with increasing sediment depth, being the distribution of ¹³⁷Cs indicative of higher diffusion within the upper 2 cm. This study on the removal of ¹³⁷Cs, ⁵⁴Mn and ⁵⁷Co from tidal water by mangrove sediments suggests that while ⁵⁷Co and ⁵⁴Mn presented closer behaviors, there was a slightly higher mobility of ¹³⁷Cs.     

The effect of environmental factors on the uptake of 60Co by Paecilomyces catenlannulatus

Paecilomyces catenlannulatus (P. catenlannulatus), a kind of important pathogenic fungi of forest pests, can be regarded as an excellent material to retard the fate and transport of radionuclides. The effect of environmental factors (i.e., pH, ionic strength, temperature and solution concentration) on the uptake of ⁶⁰Co by P. catenlannulatus was investigated by batch technique. The results showed that the uptake of ⁶⁰Co by P. catenlannulatus was independent of pH at pH < 5.0, whereas the enhanced uptake of ⁶⁰Co was observed with increasing pH from 5.0 to 8.0, then remained the high-level uptake at pH > 8.0 due to occurrence of precipitates. It is found that ⁶⁰Co uptake significantly decreased with increasing ionic strength at low pH, whereas little change was observed at high pH. The pH dependence adsorption indicates that the interaction mechanism between ⁶⁰Co and P. catenlannulatus is ion exchange at low pH and surface complexation at high pH conditions, respectively. Compared to Freundlich model, the adsorption isotherms can be fitted by Langmuir model very well. The thermodynamic data calculated from the temperature adsorption isotherms indicated that the uptake process of ⁶⁰Co by P. catenlannulatus was an endothermic and spontaneous process. This paper focused on potential application of P. catenlannulatus as suitable bio-materials for the preconcentration and removal of radionuclides from aqueous solutions in environmental pollution management.     

HPLC-spectrophotometric detection of trace heavy metals via ‘cascade’ separation and concentration

A cascade pre-concentration and separation system involving continuous solid-phase extraction and one-drop solvent concentration was developed to enable high-performance liquid chromatography (HPLC) determination of trace levels of Ni(II), Co(II), Cu(II), Se(IV) and Cr(VI) ions in aqueous solution via complexation with sodium diethyldithiocarbamate. The metal complexes were almost completely adsorbed on the solid phase (octadecylsilyl packed column). Ethyl acetate (eluent) containing the metal complexes was then placed in a centrifuge tube, to which a microvolume of dimethyl sulfoxide (DMSO) was added. Successful pre-concentration of the metal complexes into the DMSO phase was accomplished by removing the ethyl acetate using a compact evaporator in a water bath (40°C); 1000-fold concentration was achieved within 45 min. A portion of the residual DMSO phase was then subjected to HPLC analysis. The proposed method has high reproducibility and high sensitivity with detection limits (3σ) for Ni(II), Co(II), Cu(II), Se(IV) and Cr(VI) ions of 0.08, 0.11, 0.12, 0.44 and 0.20 µg/L, respectively. Relative standard deviations (RSDs) (n = 5) at Ni(II) 5.87 µg/L, Co(II) 5.89 µg/L, Cu(II) 6.35 µg/L, Se(IV) 7.90 µg/L and Cr(VI) 5.20 µg/L (1.0 × 10^?7 mol/L each) were 4.0%, 4.6%, 4.6%, 7.2% and 3.4%, respectively.     

Bioaccumulation of <Superscript>137</Superscript>Cs and <Superscript>60</Superscript>Co by bacteria isolated from spent nuclear fuel pools

This paper is focused on a characterization of bacterial contamination in pool water of the interim spent fuel storage (JAVYS Inc.) in Slovak Republic and on bioaccumulation of ¹³⁷Cs and ⁶⁰Co by isolated bacteria. Bacterial community in pool water is kept on very low level by extremely low concentration of solutes in deionized water and by the efficient water filtration system. Based on standard methods and sequencing of 16S rDNA four pure bacterial cultures were identified as Kocuria palustris, Micrococcus luteus, Ochrobactrum spp. and Pseudomonas aeruginosa. Isolated aerobic bacteria were able to bioaccumulate ¹³⁷Cs and ⁶⁰Co in laboratory experiments. The mechanism of Co and Cs binding involve rapid interactions with anionic groups of the components of cell surface and in the case of Cs⁺ ions is followed by transport processes across cytoplasm membranes and by intracellular distribution. The maximum specific uptake of Cs⁺ after 48 h cultivation in mineral medium (MM) reached 7.54 ± 0.48 μmol g^?1 dw (Ochrobactrum spp.), 19.6 ± 0.1 μmol g^?1 dw (M. luteus) and 20.1 ± 2.2 μmol g^?1 dw (K. palustris). The maximum specific uptake of Co²⁺ after 24 h cultivation in MM reached 31.1 ± 3.5 μmol g^?1 dw (Ochrobactrum spp.), 86.6 ± 12.2 μmol g^?1 dw (M. luteus) and 16.9 ± 1.2 μmol g^?1 dw (K. palustris). These results suggest that due to the long lasting uptake of ¹³⁷Cs, ⁶⁰Co and other radionuclides by biofilm in pool water high specific radioactivities (Bq m^?2) can be expected on stainless steel walls of pools.     

Radionuclide concentrations in two sewage treatment plants on Western Lake Ontario,Canada

Radionuclide concentrations in digester sludge and effluent samples from Hamilton and Dundas sewage treatment plants, located at the western tip of Lake Ontario, have been determined by high-resolution γ-ray spectrometry. The radionuclides⁵¹Cr,⁷⁵Se and¹³¹I, which are used in nuclear medicine procedures, were found in sludge samples. Very low concentrations of⁵¹Cr, entering Lake Ontario through the Hamilton plant effluent discharge, have little effect on lake water quality.     

Applicability of Microaerobic Technology to Enhance BTEX Removal from Contaminated Waters

As the addition of low concentrations of oxygen can favor the initial degradation of benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds, this work verified the applicability of the microaerobic technology to enhance BTEX removal in an anaerobic bioreactor supplemented with high and low co-substrate (ethanol) concentrations. Additionally, structural alterations on the bioreactor microbiota were assessed throughout the experiment. The bioreactor was fed with a synthetic BTEX-contaminated water (~ 3 mg L^?1 of each compound) and operated at a hydraulic retention time of 48 h. The addition of low concentrations of oxygen (1.0 mL min^?1 of atmospheric air at 27 °C and 1 atm) assured high removal efficiencies (> 80%) for all compounds under microaerobic conditions. In fact, the applicability of this technology showed to be viable to enhance BTEX removal from contaminated waters, especially concerning benzene (with a 30% removal increase), which is a very recalcitrant compound under anaerobic conditions. However, high concentrations of ethanol adversely affected BTEX removal, especially benzene, under anaerobic and microaerobic conditions. Finally, although bacterial community richness decreased at low concentrations of ethanol, in general, the bioreactor microbiota could deal with the different operational conditions and preserved its functionality during the whole experiment.     

The distribution coefficient of60Co in sediments from the Solway Firth, UK

The behaviour of⁶⁰Co in sea water and sediments typical of the Solway Firth has been investigated. The distribution coefficient,K _d, of⁶⁰Co²⁺ in sediments was determined using the batch sorption method and theK _d variation with aqueous phase composition, sediment type and pH has been studied. Adsorption of⁶⁰Co by sediments was found to be highest in de-ionised water and lower in NaCl solution (31 salinity). Adsorption was lowest in natural sea water, where theK _d range was 2,270 to 2,750. Variation ofK _d with sediment grain size was observed. It was shown that⁶⁰Co adsorption was strongly dependent on pH in de-ionised water, with less variation in NaCl solution. Variance of⁶⁰CoK _d values were lowest in sea water in the range pH 5–8 indicating a more conservative behaviour of⁶⁰Co than previously recognised. Hence⁶⁰Co dispersion will be predominantly govemed by tidal behaviour.     

Loss of trace impurities during NAA of liquid reagents

The loss of trace elements during NAA of five liquid reagents, hydrofluoric acid, hydrochloric acid, nitric acid, hydrogen peroxide and deioniyed water, has been investigated using 17 radioactive tracers of⁴⁶Sc,⁵¹Cr,⁵⁴Mn,⁵⁹Fe,⁶⁰Co,⁶⁴⁵Zn,⁷⁵Se,⁸⁵Sr,⁹⁵Zr,¹¹³Sn,¹²⁴Sb,¹⁵¹Eu,¹⁶⁰Yb,¹⁷⁷Lu,¹⁸²Ta,²³³Pa. Two kinds of container quartz and polyethylene have been used for irradiation and also for preconcentration of the reagents. The containers were cleaned before use by washing-leaching-rinsing procedure. The reagents were preconcentrated by subboiling evaporation under the infrared lamp in clean bench. The loss of trace elements has been revealed to be severer for the reagents of hydrochloric acid and nitric acid in the container of quartz than for the other cases, while that is lowest for hydrogen peroxide.     

Removal of cobalt- and mercury-EDTA chelates from aqueous solutions with a macroporous char

A bench-scale method was developed to remove cobalt- and mercury-EDTA chelates from water onto macroporous char. Experimental parameters included variations on solution pH, char pre-treatment, cobalt oxidation state, and apparatus configuration. The use of ⁶⁰Co and ²⁰³Hg radiotracers allowed for total accountability of the metals in the char and effluents. Overall experimental results demonstrate the applicability of treated macroporous chars for the effective removal of both cobalt and mercury EDTA chelates from aqueous solutions. The char system was optimized to sequester 97.5% and 99.8% of the cobalt- and mercury-EDTA from 20 ppm solutions, respectively.     

A rapid method for the determination of radionuclides in reactor coolant by ion exchange membranes

This paper deals with a rapid method to determine radionuclides in reactor coolant by anion, cation, and anion-cation exchange membranes. A high pressure filtration device was established to simulate the THOR cooling water sampling system by means of several membranes mentioned above. The experimental results indicate that the adsorption efficiency of each membrane for several radionuclides is /1/ >95% with cation exchange membrane for Zn, Co, Na, Mn, Cu, Cs, Ba, La, W etc., /2/ >98% with anion exchange membrane for I, and /3/ <98% with anion-cation exchange membranes for Fe and Cr. The results are obtained using cooling water of Tsing Hua Open-Pool Reactor and the following radionuclides were identified:^99mTc,¹⁴⁰Ba,¹⁴⁰La,⁵¹Cr,¹³¹I,⁵⁸Co,⁶⁰Co,⁵⁴Mn,⁴⁶Sc,⁵⁹Fe,²⁴Na, etc.     

Impact of environmental conditions on the sorption behavior of 60Co(II) on illite

In this work, a naturally occurring illite was characterized by using FT-IR and XRD technique to determine its surface functional groups and crystal structure. Sorption of ⁶⁰Co(II) on illite as a function of contact time, pH, ionic strength, foreign ions, humic substances and temperature was studied under ambient condition using batch technique. The results indicated that the sorption of ⁶⁰Co(II) on illite is strongly affected by pH values (2–9) and ionic strength. A positive effect of humic substances on ⁶⁰Co(II) sorption was found at pH < 7.0, whereas a negative effect was observed at pH > 7.0. At low pH, the sorption of ⁶⁰Co(II) was dominated by outer-sphere surface complexation and ion exchange with Na⁺/H⁺ on illite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The Langmuir and Freundlich models were used to simulate the sorption isotherms of ⁶⁰Co(II) at three different temperatures of 298.15, 323.15 and 343.15 K. The thermodynamic parameters (ΔH ⁰, ΔS ⁰ and ΔG ⁰) calculated from the temperature dependent sorption isotherms indicated that the sorption process of ⁶⁰Co(II) on illite was endothermic and spontaneous.     

Removal and preconcentration of lead(II), cadmium(II) and chromium(III) ions from wastewater samples using surface functionalized magnetite nanoparticles

The potential removal and preconcentration of lead(II), cadmium(II), and chromium(III) ions from wastewaters were investigated and explored. Magnetite nanoparticles were chemically modified with p-nitro aniline. The aniline-coated magnetite nanoparticles (ANMNPs) were fully characterized by FT-IR, XRD, SEM, and TEM measurements. Batch studies were performed to address various experimental parameters for the removal and determination of these ions. ANMNPs showed high tendency to investigated metal ions, in this order: Cr(III) > Cd(II) > Pb(II), owing to the strong contribution of surface loaded aniline. The potential applications of ANMNPs adsorbent for removal and preconcentration of Pb(II), Cr(III), and Cd(II) from wastewaters as well as drinking tap water samples were successfully accomplished giving recovery values of (98–101 %), without any noticeable interference of the wastewater or drinking tap water matrices.     

Determination of elements in different parts of goat brain using k 0 instrumental neutron activation analysis

Researcher’s interest is increasing worldwide to study the role of trace elements in brain tissues. This paper discusses the application of k ₀-instrumental neutron activation analysis to study the distribution of trace elements in seven different anatomical regions of goat brain. These regions include cerebellum, cerebrum, medulla oblongata, meninges, midbrain, pons and thalamus. The analysis protocol followed 1 h irradiation at 10 MW material testing type nuclear research reactor with nominal thermal neutron flux of 2 × 10¹³ cm^?2 s^?1. A total of 14 elements, namely Br, Co, Cr, Eu, Fe, Hg, K, Na, Rb, Sb, Sc, Se, Tb and Zn were determined in all parts. Reliability of the method was assessed by analyzing biological reference material IAEA-336 (lichen). On comparing the analytical results with the healthy human brain data, it showed that eight elements (Eu, K, Na, Rb, Sb, Sc, Se, Tb) were found with relatively higher elemental concentrations in human brain. Principal component analysis revealed distribution of seven parts in different three groups having similar elemental concentrations of elements.     

Concentrations and Sources of Polycyclic Aromatic Hydrocarbons in Water and Sediments from the Huaihe River,China

Surface water and sediments were collected from eleven locations on the middle region of Huaihe River to evaluate the environmental effects of urban and industrial activities. The concentrations of sixteen polycyclic aromatic hydrocarbons (PAHs) in water and sediments were between 1.2–5.1 µg/L and 72–139 ng/g, respectively. High levels of PAHs in water were recorded in comparison to those of other countries, while the concentrations in sediments were low to moderate levels. A weak positive correlation was observed (R² = 0.49, P = 0.13) between PAHs and total organic carbon in water. However, a significant positive correlation (R² = 0.79, P = 0.004) was found in sediments, which indicated that total organic carbon was a factor in PAH levels in sediments but not in water. The parent ratios were studied by principal component analysis that showed the PAHs from water were predominantly derived from coal combustion (34%), oil spills (49%), and vehicular emissions (17%), while the major PAH sources to sediments were coal combustion. Using the ecological toxic equivalency factor index, it was concluded that the PAHs levels may provide a potential risk in water but not in sediments.     

Utilization of low-cost sorbent for removal and separation of 134Cs, 60Co and 152+154Eu radionuclides from aqueous solution

Eggshell material was used as low-cost and eco-friendly biosorbent for removal of ¹³⁴Cs, ⁶⁰Co and ^152+154Eu radionuclides from aqueous solution. The eggshell material was calcined at 500 and 800 °C, and then characterized. Comparative studies on the natural and calcined eggshell for sorption of the three radionuclides were carried out. It was found that, the uptake is in the order: Eu(III) > Co(II) > Cs(I). Further, column chromatography was used in separation of ¹³⁴Cs, ⁶⁰Co and ^152+154Eu using 0.15, 0.2 and 0.5 mol/l nitric acid, respectively. Eggshell material can be considered as a promising material for separation of radionuclides from radioactive waste solution.     

Trace element content of medicinal plants from Algeria

Neutron activation analysis (INAA) has been applied to multielemental determination of eleven medicinal plants used to cure the urinary tract diseases observed in Algeria. These plants include Androgena Citratus, Ceratonia Siliquata, Punica Granatum, Glyryrrhiza Glabra, Lausaunia Alba, Fragaria Vesca, Arbutus Unedol, Hordeum Vulgaris, Papieteria Officinalis, Zea Mays L, and Davallia Seae. Concentrations of twenty elements Ba, Br, Ca, Cl, Co, Cu, Cr, Fe, I, Mn, Na, Mg, Rb, Sb, Se, Sc, Sr, Ti, V, and Zn have been determined by short, and long irradiation times with a thermal and epithermal flux of 1.4·10¹² n·cm⁻²·s⁻¹ and 1.4·10¹¹ n·cm⁻²·s⁻¹, respectively. These analyses were performed in conjunction with Compton suppression. In almost herbs studied the Co, Cr, Cu, Rb, Sb, Sc, Se and V are found to be present at trace levels, Br, Mn, and Zn at the minor level, and Ca, Cl, Fe, Mg and Na are generally at the major level. The accuracy of the measurements has been evaluated by analyzing NIST-botanical references materials.     

A comparative study of trace elements in water from various sources in surrounding areas of Nagpur city (India) by instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) has been used for the determination of 27 elements (Ag, Au, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Ga, Hg, Hf, K, La, Mn, Na, Sb, Sc, Se Sr, Th, P, Ta, Tb, Zn and Zr) in 15 water samples collected from different sources (reservoirs, well, borewell, sewage tank, river, rain) in and around Nagpur city (central India) including doubly distilled and a sea water sample from Bombay. Sample residues after evaporation were irradiated at a thermal neutron flux of 10¹²–10¹³ n·cm^–2·s^–1 for 10 min, 1d and 1wk and counted using a HPGe detector and an 4k MCA at different intervals. Several environmental standards from NIST (USA), NIES (Japan) and USGS rock were also analysed for quality assurance. Wide variations in elemental concentrations have been observed in water samples from different sources. Most elemental concentrations in drinking water from various sources, are within ISI/WHO limits. Sea water showed very high concentrations of Ba, Cr, Co, Fe, Hg, Sb, Se and Zn. For doubly distilled and rain waters, however, very low elemental concentrations of Ba, Ce, Fe, Sc, Hg, Se, Sr and Th were observed.     

Electrocatalytic oxidation and sensitive determination of l-cysteine at a poly(aminoquinone)-carbon nanotubes hybrid film modified glassy carbon electrode

A matrix removal procedure has been developed for the determination of trace elements, including As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Tl, Zn and V, in siliceous materials by inductively coupled plasma mass spectrometry (ICP-MS). Soil and sediment samples were dissolved in a mixture of HNO₃ and HF in sealed vessels by using a microwave oven. Silicon matrix in the solutions was precipitated as sparingly soluble sodium fluorosilicate (Na₂SiF₆) by adding 0.5 mL of 300 mg mL⁻¹ NaCl solution. Simultaneous precipitation of sodium and silicon was achieved in highly acidic solutions containing 30–40% (v/v) HNO₃. A mixture of methanol and nitric acid afforded back-extraction of the trace elements without significant dissolution of the Na₂SiF₆. Samples were analyzed by ICP-MS for trace elements and residual silicon. Calibration was made by aqueous multi-element standard solutions. Up to 95% of the silicon was successfully removed yielding solutions suitable for introduction to ICP-MS. The method was validated by analysis of two NIST certified reference materials; SRM 2711 (Montana Soil) and SRM 2704 (Buffalo River Sediment). Accurate results were obtained for all elements, including those for As, Hg and Se that suffer from losses due to the presence of their volatile species when silicon was converted to volatile SiF₄ via heat-assisted evaporation to dryness. The recoveries from the SRM samples varied between 80% (Cr) and 109% (Hg). No significant interferences were observed from molecular ions of chloride and residual sodium on ⁷⁵As, ⁶³Cu, ⁶⁰Ni, ⁷⁷Se and ⁵¹V. Correspondence: Zikri Arslan, Department of Chemistry, Jackson State University, Jackson, MS 39217, USA     

Concentration and pollution assessment of hazardous metal elements in sediments of the Xiangjiang River, China

The concentrations of 21 metals in surface sediments collected from 16 stations in lower reach of Xiangjiang River (Zhuzhou–Xiangtan–Changsha section) were determined by using high-resolution inductively coupled plasma mass spectroscopy and their pollution levels were assessed by applying enrichment factor (EF), the geo-accumulation index (I _geo) and pollution index (PI). The results show the total concentrations in μg g^?1 are as follows: 1.80–14.88 for Sc, 16.66–144.29 for V, 13.27–87.99 for Cr, 159.50–2413.74 for Mn, 2.21–23.14 for Co, 4.71–42.45 for Ni, 5.31–188.89 for Cu, 38.41–1250.47 for Zn; 5.1–22.15 for Ga, 91.8–161.57 for Rb, 20.4–62.51 for Sr, 0.2–2.45 for Mo, 0.9–81.79 for Cd, 3.8–30.3 for Sn, 5.9–18.33 for Cs, 208.10–464.74 for Ba, 1.6–22.05 for W, 18.90–198.01 for Pb, 0.3–8.54 for Bi, 2.6–18.27 for Th, 0.6–13.62 for U. The mean concentrations in sediments divided by the UCC value decrease in the order of Cd > Bi > W > Zn > Pb > Cs > Sn > Mn > Cu > 1.5 times > Cr > U = Ni > V > Co > Rb > 1.0 time > Th > Ga > Sc > Mo > Ba > Sr. The calculated EF and I _geo of metals implied the lower reach of Xiangjiang River had widespread been polluted by Cd, Bi, W, Cs, Pb, Zn, Sn, and locally been polluted by Cu and Mn, and not been polluted by other 12 metals. The PI values indicated almost all stations had been polluted by metals in this river.