Isolation and alpha-particle spectrometric determination of238Pu and239,240Pu in sediments

A simple method is described for the isolation and determination of plutonium isotopes in sediments. The method involves leaching of sample with nitric acid and subsequent separation of plutonium on an anion-exchange column. Major matrix elements and several potential radiochemical interferences are removed during 8M HNO₃ sample loading on the column. Thorium is removed by thorough washing with 10M HCl. Plutonium (IV) is eluted with 4M HCl. Source for alpha-particle spectrometry is prepared by LaF₃ coprecipitation technique at which stage a complete separation from uranium(VI) is also achieved. The entire analytical procedure is completed in about two days.     

Rapid method for plutonium-241 determination in soil samples

A simple and rapid procedure for the determination of plutonium isotopes in the environment is presented. The procedure combines alpha spectrometry, solvent extraction and liquid scintillation measurements to ensure that both alpha- and beta-emitting isotopes are determined. Of five tested extractants, bis-(2-ethylhexyl) phosphoric acid was found to be the best choice. The procedure was applied to soil samples contaminated with Chernobyl fallout.     

Metals for the containment of nitric acid solutions of plutonium-238

Results of a study of the corrosion of various transition-metal alloys, tantalum, and tantalum/2.5% tungsten are reported. The solvent contained nitric acid, hydrofluoric acid, and ammonium hexanitratocerate. It was designed to imitate the corrosiveness of the nitric acid, hydrofluoric acid mixture used to dissolve 238-plutonium dioxide.     

A simple method for the determination of natural uranium and226Ra in waters and soils

A procedure for the determination of natural uranium and²²⁶Ra in waters and soils has been carried out and applied to the analysis of samples for environmental radiological monitoring.²²⁶Ra determination consists of co-precipitation with BaSO₄,²²²Rn emanation in toluene and finally liquid scintillation counting. Natural uranium is then determined by a fluorometric technique. This paper describes the method and the conditions that were tested to optimize it. The technique was found to be suitable for the analysis of surface and ground waters, samples from rivers, streams and lakes and soil samples, because of its few steps, short processing time, high recovery percentages and suitable detection limits.     

Determination of plutonium-239,240 in environmental samples from surroundings of the Atomic Power Station Jaslovské Bohunice

Specific activity of^239,240Pu in contaminated soils from the bank of Manivier channel was determined to be in the range of 5–40 Bq·kg^?1 and for soils from the bank of Dudvah river 0.6–8 Bq·kg^?1. The ratio of^239,240Pu/¹³⁷Cs found in the samples is about 1·10^?4, which is very close to the ratio found in the pulp of high activity concentrate in the collecting tank of nuclear power plants (NPP).     

Extraction-chromatographic determination of hydrazine in natural water as a 5,7-Dinitrobenzofurazan derivative using diode-array detection

The conditions for the derivatization of hydrazine withp-dimethylaminobenzaldehyde and 4-chloro-5,7-dinitrobenzofurazan, extraction preconcentration of derivatives from natural water, and HPLC determination of the toxicant with diode-array detection were studied. The 5,7-dinitrobenzofurazan derivative was quantitatively extracted from water with isoamyl alcohol and a mixture of isoamyl alcohol with methylene chloride at pH 3–4. A procedure was developed for the extraction-chromatographic determination of hydrazine in water with c_min = 0.05 Μg/L and the analytical range 0.12-60 Μg/L. The concentration of hydrazine in lake Kaban water was determined.     

On peculiarities of vertical distribution of 239,240Pu, 238Pu and 137Cs activity concentrations and their ratios in lake sediments and soils

Distributions of ^239,240Pu, ²³⁸Pu and ¹³⁷Cs activity concentrations in the cores of sediments in the shallow lake, flooded and upland forest soils taken in the vicinity of Vilnius city were analyzed. The radiochemical, α-spectrometric and mass spectrometric methods were used for the plutonium evaluation and γ-spectrometry was used for the radiocesium evaluation. The only peak of enhanced radionuclide activity concentrations was determined for the lake bottom sediments, whereas vertical profiles of the radionuclide activity concentrations in flooded and upland forest soil cores were distinguished by two peaks. The obtained values of the activity concentration ratio ²³⁸Pu/^239,240Pu and the isotopic ratio ²⁴⁰Pu/²³⁹Pu indicated that the global fallout was a source of plutonium in the investigated environment. Chernobyl-derived radiocesium was detected solely in the surface layers (2–11 cm) of the studied sample cores. The contribution of the Chernobyl deposits amounted to about 2.26, 6.11 and 20.9 % of the total radiocesium inventory in the bottom sediments, the upland soil and flooded soil, respectively.     

Extraction-chromatographic preconcentration with chromatomembrane separation of extract from aqueous phase for luminescence determination of oil products and phenols in natural water by flow injection analysis

The new method of preconcentration by extraction for flow injection analysis (FIA) with luminescence and photometric detection is proposed. Preconcentration is carried out on extraction-chromatographic column, extract is eluted by extragent with the following separation of extract from aqueous phase in chromatomembrane cell. Possibilities of the proposed method are illustrated in the examples of FIA with luminescence determination of oil products and phenols in natural water.     

Extraction-chromatographic determination of sulfonated azo dyes in aqueous solutions

The extraction of sulfonated azo dyes E102, E110, E122, E124, and E129 from aqueous solutions using hydrophilic solvents and their mixtures in the presence of a salting-out agent (ammonium sulphate) has been studied. Some regularities of extraction have been revealed. The composition of the mobile phase has been optimized and a procedure has been proposed for the identification and determination of the dyes in aqueous solutions by thin-layer chromatography in concentrations of 0.1–0.01 μg/L. An office scanner and a personal computer have been used to process the results of the separate determination of the dyes.     

An analytical method for determination of fullerenes and functionalized fullerenes in soils with high performance liquid chromatography and UV detection

Fullerenes are carbon-based nanomaterials expected to play a major role in emerging nanotechnology and produced at an increasing rate for industrial and household applications. In the last decade a number of novel compounds (i.e. fullerene derivatives) is being introduced into the market and specific analytical methods are needed for analytical purposes as well as environmental and safety issues. In the present work eight fullerenes (C60 and C70) and functionalized fullerenes (C60 and C70 exohedral-derivatives) were selected and a novel liquid chromatographic method was developed for their analysis with UV absorption as a method of detection. The resulting HPLC-UV method is the first one suitable for the analysis of all eight compounds. This method was applied for the analysis of fullerenes added to clayish, sandy and loess top-soils at concentrations of 20, 10 and 5 μg kg⁻¹ and extracted with a combination of sonication and shaking extraction. The analytical method limits of detection (LoD) and limits of quantification (LoQ) were in the range of 6–10 μg L⁻¹ and 15–24 μg L⁻¹ respectively for the analytical solutions. The extraction from soil was highly reproducible with recoveries ranging from 47 ± 5 to 71 ± 4% whereas LoD and LoQ for all soils tested were of 3 μg kg⁻¹ and 10 μg kg⁻¹ respectively. No significant difference in the extraction performance was observed depending of the different soil matrices and between the different concentrations. The developed method can be applied for the study of the fate and toxicity of fullerenes in complex matrices at relatively low concentrations and in principle it will be suitable for the analysis of other types of functionalized fullerenes that were not included in this work.     

Effect of the natural radioactivity concentrations and 226Ra/238U disequilibrium on cancer diseases in Penang,Malaysia

Natural radioactivity measurements and assessment of radiological hazards in soil and sand samples obtained from Penang, Malaysia were carried out using the Exploranium GR-135 Plus “Identifier” Radioisotope Identification Device and high-resolution High Purity Germanium (HPGe) detector system. The activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 184±11, 396±22, 165±14, and 835±28 Bq kg^?1 respectively, and the external gamma dose rate is 315±44 nGy h^?1 for soil samples. For sand samples, the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 31±8, 62±16, 36±6, and 369±17 Bq kg^?1, respectively, and the external gamma dose rate is 66±12 nGy h^?1. To assess the radiological hazard of radioactivity present in the samples, the radium equivalent activity, annual effective dose, annual gonadal dose equivalent, external hazard, and internal indices were calculated.The Ra_eq values of soil samples were higher than the limit of 370 Bq kg^?1, which is equivalent to a gamma dose of 1.5 mSv yr^?1, whereas the Ra_eq for sand samples was lower than 370 Bq kg^?1. The calculated concentrations by HPGe spectroscopy were compared with the measured concentrations detected by a GR-135 spectrometer. The calculated and measured gamma dose rates had an ideal correlation coefficient R of 0.72. The gamma dose rates in Penang increased with the average annual age-standardized rates (ASR) for all cancers between 1994 and 2010. The effects of the pH value of soil and sand samples on natural radionuclides concentrations were investigated. The high concentration of ²²⁶Ra/²³⁸U ratio disequilibrium (²²⁶Ra/²³⁸U of 1.76–2.33) was observed in the sampling sites. Moreover, a portable continuous radon monitor (SNC, model 1029, Sun Nuclear Corporation) was used to measure the radon concentration of the soil surface. The radon concentrations were found to vary from 7 to 50 Bq m^?3. A positive correlation was observed between the radon and radium concentrations in samples measured by the SNC continuous radon monitor and HPGe detector.     

Concentrations of239,240Pu and238Pu in the surface air of Prague in 1993, 1994 and 1995

The activity concentration of^239,240Pu and²³⁸Pu in the surface air of Prague in the years 1993, 1994 and 1995 have been determined. The content of^239,240Pu in air in different monitoring periods of the years studied ranged from <0.5 to 5.5 nBq.m^–3. The source of^239,240Pu in air is the resuspension of fallout plutonium from the opsoil layer.     

Fluorimetric method for the determination of uranium in natural waters

A method is described for the fluorimetric determination of uranium in natural waters. The limit of detection is 0.3 ppM. Ion-exchange is used to preconcentrate the uranium by a factor of 22 and separate it from quenching ions in the sample. The fluorescence is measured in a medium that is 1.35M in both sulphuric and phosphoric acids. The uranyl ions are excited by radiation of wavelength 280 nm and bandwidth 40 nm. The emitted signal is scanned from 470 to 510 nm. After spiking of the sample solution with a small volume of standard uranium solution, the fluorescence signal is scanned again and the uranium content of the sample calculated from the two readings. The coefficient of variation is 8.5% for determinations of U in a synthetic water sample having a uranium content of 1.9 ppM. Destruction of organic matter in the eluates gives 0.1 ppM detection limit.     

The Dutch norm for the determination of natural radioactivity levels in construction materials applied to concrete samples

In the near future, Dutch legislation will set an upper limit for thenatural radiation exposure of inhabitants in newly built houses. Therefore,it is necessary to have standardized procedures available for the determinationof the radon exhalation rate of and the activity levels in construction materials.In this paper we describe a method for determination of activity levels inconstruction materials. This method comprises radionuclide-specific calibrationof Marinelli-beaker geometries with a range of material densities. This standardmethod was validated in a round-robin involving 6 laboratories, organizedby two of the authors (M.B. and H.J.G.) of this paper. In this paper, resultsobtained according to the norm are compared with results obtained at IRI witha more elegant but possibly less robust method.     

Improved method for the determination of sulfur components in natural gas

Determination of trace concentrations of sulfur components in natural gas is a true analytical challenge. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by environmental regulation institutions and modern chemical industry. In the present contribution the sample pretreatment and chromatographic separation steps have been evaluated and optimized based on the use of a flamebased sulfur chemiluminescence detector (SCD) for target compound detection. The proposed instrument consists of a programmed temperature vaporizing (PTV) injector employing a liner packed with Chromosorb 104, a 4 μm thick film apolar column and a flame-based SCD. Using a 13 mL sample loop the detection limit achievable with the new method is 3 μg S/m³. The precision of replicate measure. ments is generally in the range of 5–15% relative standard deviation. Lower detection limits can be achieved by preconcentrating larger sample volumes, e.g. 100 mL.     

Depth distribution of239,240Pu and137Cs in soils of South Korea

Depth distribution of^239,240Pu and¹³⁷Cs in the soils of South Korea have been studied. The average accumulated depositions were estimated roughly to be 54.8±32.1 Bq·m^–2 for^239,240Pu, 1.6±1.0 Bq· ·m^–2 for²³⁸Pu and 1982.8±929.1 Bq·m^–2 for¹³⁷Cs. The activity ratios of^239,240Pu/¹³⁷Cs in soils were found to be in the narrow range of 0.0153 to 0.0364 with a mean value of 0.0230±0.006. The concentrations of^239,240Pu and¹³⁷Cs in soils decrease exponentially with increasing the soil depth. A significant correlation was found between the concentration of^239,240Pu and that of¹³⁷Cs. The activity ratios of^239,240Pu/¹³⁷Cs tend to increase slightly with increasing soil depth.     

Natural and fallout radioactivity measurement in Indian soils

The paper presents the results of high resolution gamma-spectrometric measurements of ¹³⁷Cs, ⁴⁰K, ²³²Th and ²³⁸U in Indian soils collected from 24 different places from normal natural radiation background areas. The depth profile of ¹³⁷Cs was studied at sampling sites. The paper also presents ¹³⁷Cs levels in top soil at Mumbai during 1986 to 2000. The results in Mumbai soil indicate clearly the accumulation from fallout only on the top soil and seasonal peaking during the beginning of the monsoon season.     

Concentration of 238U and 232Th among constituent minerals of two igneous plutonic rocks exhibiting elevated natural radioactivity levels

The concentrations of ²³⁸U and ²³²Th of the constituent minerals in two plutonic rock samples, from N. Greece, exhibiting elevated levels of bulk rock natural radioactivity were determined by using LA-ICP-MS. The available data of whole rock ²³⁸U and ²³²Th concentrations were also used. The minerals were separated using a combination of heavy liquids of various densities, shaking table and magnetic separation techniques. The great variation in the concentrations of ²³⁸U and ²³²Th is probably indicative of the different distribution of U and Th within the same rock, as well as to secondary post-magmatic processes that were responsible for the redistribution of U and Th. An estimation of the contribution of each mineral constituent to the natural radioactivity levels of the bulk rock is attempted. Thorite and zircon contribute the most to the whole rock ²³⁸U and ²³²Th content, while the contribution of apatite is moderate. The contribution of the rest of the minerals examined (fluorite, quartz, plagioclase, K-feldspar, amphibole, pyroxene, magnetite and biotite) is not important.     

A semi-automated method for the determination of total arsenic and selenium in soils and sediments

Acid digestion with nitric, perchloric and hydrofluoric acids under oxidizing conditions with addition of permanganate and persulfate is utilized to extract inorganic and organic forms of arsenic and selenium from all phases of sediments including the silicate lattice. After sample dissolution a completely automated system is used to reduce arsenic and selenium to their corresponding hydrides and determine them by quartz-tube atomic absorption spectrometry. The method is directly applicable to batch routine analysis of large numbers of environmental samples.