The dietary intake of238U,234U,230Th,232Th,228Th and226Ra from food and drinking water by inhabitants of the Walbrzych region

Intake with food and water of the natural radionuclides of the uranium and thorium series was determined for adult population of the south-western region in Poland, where in the 1950-ies an exploration of uranium ore was conducted. Concentration of the radionuclides was determined in food products and drinking water and their annual intake was estimated on the basis of the average annual consumption. The intake of²³⁸U,²³⁴U and²³⁰Th occurred mainly with water (33% to 68%), whereas the intake of²³²Th,²²⁸Th and²²⁶Ra was mainly with vegetables, potatoes, milk and flour. From the intake and dose coefficients the annual effective doses from the ingested radionuclides were calculated. The total dose was 5.6 Sv, of which 74% originated from²²⁶Ra.     

Distribution of 238U, 226Ra, 232Th and 40K in soil samples around Tarapur,India

The radioactivity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K in soil samples around Tarapur vary from 11.5 ± 2.6 to 50.3 ± 6.6, 14.9 ± 0.6 to 40.5 ± 1.2, 18.1 ± 0.4 to 75.0 ± 1.5 and 130.1 ± 1.6 to 295.1 ± 2.6 Bq/Kg respectively. The measured activity concentrations for ²³⁸U and ²²⁶Ra were compared and found in good agreement with the Indian as well as world average. The average ²³²Th and ⁴⁰K concentrations in Tarapur were lower than the Indian average value.     

Measurements of238U,234U and230Th in impure carbonates for age determination

The carbonate cements of conglomeritic deposits of late Pleistocene age have been leached with 0.2N hydrochloric acid and analyzed radiochemically. The leachate and the residue fractions were separately measured for²³⁸U,²³⁴U and²³⁰Th, using isotope-dilution and alpha-spectrometric techniques. The data are used to estimate the isotopic activities of uranium and thorium in the carbonate phase. These activities give age information for the carbonate cementation. Ages in the range of 185–320·10³ years were obtained for the samples studied.     

226Ra, 228Ra and 210Pb Isotopes in Some Water Samples of Mines

A method for the determination of ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb in water samples of mining regions by measuring the and intensities with the help of a liquid scintillation counter is presented. The high-energy part of the -particle spectrum emitted by ²¹⁰Bi is used for the determination of ²¹⁰Pb content in the samples. An attempt is also given to explain the radioactive disequilibrium between ²²⁶Ra and ²¹⁰Pb in the samples investigated.     

Comparison of transfers for natural radionuclides (238U, 234Th, 226Ra, 210Pb & 210Po) from five different soils to four different barley genotypes

Transfer Factors (Fv) of ²³⁸U, ²²⁶Ra, ²³⁴Th, ²¹⁰Po and ²¹⁰Pb from five different agricultural soils in semi-arid region (Syria) to four different barley genotypes were studied in an agricultural potted experiment. The geometric mean of the Fv values were (0.08) for ²¹⁰Pb, and (0.02) for ²¹⁰Po, while it ranged from 0.18 to 0.42 ,from 0.08 to 0.15 and from 0.22 to 0.4 for ²³⁸U, ²³⁴Th and ²²⁶Ra, respectevily. The Fv values of ²³⁸U and ²²⁶Ra were within the recommended global medians, while the Fv values of ²³⁴Th, ²¹⁰Pb and ²¹⁰Po were higher. There is no clear relationship between the soil properties and Fv of all studied radionuclides to barley genotypes. Moreover, the expression of glutathione (GSH) gene, which is belived to be involoved in heavy metal removal was generally low in all studied varieties grown in all soil types.

     

Determination of228Th,230Th,and232Th in environmental samples from uranium mining and milling operations

A method is described for the determination of²²⁸Th,²³⁰Th, and²³²Th in environmental samples from uranium mining and milling operations. The analytical procedure is based on the direct determination of²²⁸Th in the sample by high resolution γ-spectrometry followed by extraction and purification of the thorium fraction using high molecular weight amines and an anion-exchange technique, respectively, prior to α-spectrometry to determine isotopic ratios. The lowest level of detection for each thorium isotope is 0.01 pCi/g for solid samples and 20 pCi/l for aqueous samples. Replicate analyses of a typical mine waste stream gave a standard deviation of ±3% for²²⁸Th. Standard deviations of the²³⁰Th and²³²Th increased to ±11% apparently due to traces of²¹⁰Po interfering in the α-spectrometry.     

Rapid method for 226Ra and 228Ra analysis in water samples

Summary The measurement of radium isotopes in natural waters is important for oceanographic studies and for public health reasons. Radium-226 (T_1/2 = 1620 y) is one of the most toxic of the long-lived alpha-emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The analysis of ²²⁶Ra and ²²⁸Ra in natural waters can be tedious and time-consuming. Different sample preparation methods are often required to prepare ²²⁶Ra and ²²⁸Ra for separate analyses. A rapid method has been developed at the Savannah River Environmental Laboratory that effectively separates both ²²⁶Ra and ²²⁸Ra (via ²²⁸Ac) for assay. This method uses MnO₂ Resin from Eichrom Technologies (Darien, IL, USA) to preconcentrate ²²⁶Ra and ²²⁸Ra rapidly from water samples, along with ¹³³Ba tracer. DGA Resin^ò (Eichrom) and Ln-Resin^ò (Eichrom) are employed in tandem to prepare ²²⁶Ra for assay by alpha-spectrometry and to determine ²²⁸Ra via the measurement of ²²⁸Ac by gas proportional counting. After preconcentration, the manganese dioxide is dissolved from the resin and passed through stacked Ln-Resin-DGA Resin cartridges that remove uranium and thorium interferences and retain ²²⁸Ac on DGA Resin. The eluate that passed through this column is evaporated, redissolved in a lower acidity and passed through Ln-Resin again to further remove interferences before performing a barium sulfate microprecipitation. The ²²⁸Ac is stripped from the resin, collected using cerium fluoride microprecipitation and counted by gas proportional counting. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.     

Gamma spectrometry of 234Th (238U) in environmental samples

Environmental samples from a wide-range of aquatic and soil deposits, mainly of Scandinavian origin, were analysed for 234Th (238U) using low-level gamma-spectrometry. The diversity of the samples, in terms of composition and ages, allowed a detailed evaluation of the analytical problems associated with gamma-ray spectrometry with focus on the reliability of the 234Th peaks for absolute determination of the 234Th activities. The X-ray contributions in the 93 keV peak were compared with the corresponding self-absorption corrected activities of the 63 keV peak. These X-ray contributions were, also, correlated with the 238U, 232Th, 235U, 40K and 137Cs activities of the samples. Despite the difficulties imposed by the self-absorption corrections, the 63 keV peak is still the best option. Large variability in the 93 keV peak interferences, due to X-rays from Th, exists in sediment and soil samples. Only in the case of young ombrotrophic peat samples was it possible to conclude that the 93 keV peak is free from X-ray contributions and can be as good as the 63 keV Monte-Carlo self-absorption corrected peak. X-ray contributions in the samples correlated with the 238U and 232Th activities, only, in closed environmental systems where a secular equilibrium with the daughters of the U/Th series can occur.     

Activity concentrations of238U and226Ra in agricultural samples

Distributions of²³⁸U and²²⁶Ra in agricultural samples and cultivated soils have been studied over ten years. The crops are rice, spinach and Chinese cabbage. Two investigated areas have been selected (35° 18 N, 113° 35 E). The agricultural samples and soils were collected annually from May 1982 through October 1991. The activity concentrations of²²⁶Ra in agricultural samples are greater than those of²³⁸U. The transfer factors of²³⁸U,²²⁶Ra are from 0.06·10^–3 to 1.2·10^–3. The²²⁶Ra/²³⁸U ratios for three agricultural samples have their characteristic values.     

The determination of134Cs,137Cs,210Pb,226Ra and228Ra concentrations in nearshore marine sediments and seawater

Multi-radionuclide analyses of coastal marine sediments and seawater can be of considerable value in defining rates and mechanisms of nearshore processes. A preliminary study of¹³⁴Cs,¹³⁷Cs,²¹⁰Pb,²²⁶Ra and²²⁸Ra in the Clyde Sea Area has been performed. A summary of the marine geochemistries of these species and a detailed account of methods involved in their routine analysis are described.     

Rapid determination of 226Ra in environmental samples

A new rapid method for the determination of ²²⁶Ra in environmental samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for emergency response or routine sample analyses. The need for rapid analyses in the event of a Radiological Dispersive Device or Improvised Nuclear Device event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. ²²⁶Ra (T1/2?=?1,620?years) is one of the most toxic of the long-lived alpha-emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The new method to determine ²²⁶Ra in environmental samples utilizes a rapid sodium hydroxide fusion method for solid samples, calcium carbonate precipitation to preconcentrate Ra, and rapid column separation steps to remove interferences. The column separation process uses cation exchange resin to remove large amounts of calcium, Sr Resin to remove barium and Ln Resin as a final purification step to remove ²²⁵Ac and potential interferences. The purified ²²⁶Ra sample test sources are prepared using barium sulfate microprecipitation in the presence of isopropanol for counting by alpha spectrometry. The method showed good chemical recoveries and effective removal of interferences. The determination of ²²⁶Ra in environmental samples can be performed in less than 16?h for vegetation, concrete, brick, soil, and air filter samples with excellent quality for emergency or routine analyses. The sample preparation work takes less than 6?h. ²²⁵Ra (T1/2?=?14.9?day) tracer is used and the ²²⁵Ra progeny ²¹⁷At is used to determine chemical yield via alpha spectrometry. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory radium particles are effectively digested. The preconcentration and column separation steps can also be applied to aqueous samples with good results.     

On the use of232U and its daughters for the determination of226Ra in water samples

The authors propose a method to determine 226Ra by using a solution of²³²U and its daughters in equilibrium as a tracer.²²⁴Ra of the²³²U solution can be used as yield determinant for²²⁶Ra. The growth of²¹⁴Po from²²⁶Ra and of²¹²Po from²²⁴Ra is measured at different times after the isolation of the radium fraction.     

226Ra, 228Ra and 228Ra/226Ra in surface marine sediment of Malaysia

Surface sediment samples were collected at the West (east coast and west coast of Peninsular Malaysia) and East (Sabah and Sarawak) Malaysia in several expeditions within August 2003 until June 2008 for determining the level of natural radium isotopes. Activity concentrations of ²²⁶Ra and ²²⁸Ra in surface marine sediment at 176 sampling stations were measured. The activity concentrations of both radionuclides in Malaysia (East and West Malaysia) display varied with the range from 9 to 158 Bq/kg dry wt. and 13 to 104 Bq/kg dry wt., respectively. Meanwhile, the ratio distributions of ²²⁸Ra/²²⁶Ra were ranged from 0.62 to 3.75. This indicated that the ratios were slightly high at west coast of Peninsular Malaysia compared to other regions (east coast of Peninsular Malaysia, Sabah and Sarawak). The variation of activity concentrations of ²²⁶Ra and ²²⁸Ra and its ratios were also supported by the statistical analyses of one-way ANOVA and t test at 95 % confidence level, whereby there were proved that the measured values were different between the regions. These different were strictly related to their half-life, potential input sources (included their parents, ²³⁸U and ²³²Th), parent’s characteristic, the geological setting/formation of the study area, environment origin and behavior.     

Rapid method for determination of 228Ra in water samples

A new rapid method for the determination of ²²⁸Ra in natural water samples has been developed at the SRNL/EBL (Savannah River National Lab/Environmental Bioassay Laboratory) that can be used for emergency response or routine samples. While gamma spectrometry can be employed with sufficient detection limits to determine ²²⁸Ra in solid samples (via ²²⁸Ac), radiochemical methods that employ gas flow proportional counting techniques typically provide lower minimal detectable activity levels for the determination of ²²⁸Ra in water samples. Most radiochemical methods for ²²⁸Ra collect and purify ²²⁸Ra and allow for ²²⁸Ac daughter ingrowth for ~36 h. In this new SRNL/EBL approach, ²²⁸Ac is collected and purified from the water sample without waiting to eliminate this delay. The sample preparation requires only about 4 h so that ²²⁸Ra assay results on water samples can be achieved in <6 h. The method uses a rapid calcium carbonate precipitation enhanced with a small amount of phosphate added to enhance chemical yields (typically >90 %), followed by rapid cation exchange removal of calcium. Lead, bismuth, uranium, thorium and protactinium isotopes are also removed by the cation exchange separation. ²²⁸Ac is eluted from the cation resin directly onto a DGA Resin cartridge attached to the bottom of the cation column to purify ²²⁸Ac. DGA Resin also removes lead and bismuth isotopes, along with Sr isotopes and ⁹⁰Y. La is used to determine ²²⁸Ac chemical yield via ICP-MS, but ¹³³Ba can also be used instead if ICP-MS assay is not available. Unlike some older methods, no lead or strontium holdback carriers or continual readjustment of sample pH is required.     

A practical and accurate method for the determination of 234Th simultaneously with 210Po and 210Pb in seawater

A practical technique has been developed for the determinations of (234)Th simultaneously with (210)Po and (210)Pb in seawater samples, which greatly simplifies the on-board chemical procedures and enables an accurate correction of (234)Th ingrowth. A unique feature of this technique lies in the exact determination of co-precipitated (238)U following Fe(OH)(3) precipitation which leads to an exact correction of ingrown (234)Th between Fe(OH)(3) precipitation and U/Th separation. Such a correction eliminates several cumbersome on-board chemistry steps (such as Po plating, Fe(2+) oxidation, and 9 N HCl anion exchange) required in regular procedures to eliminate the (234)Th ingrowth. The total time required for on-board sample treatment (spike equilibration, Fe (OH)(3) co-precipitation and filtration) could be less than 10 h which significantly increases the sample processing efficiency and data throughput.     

A comparison of methods for the determination of the dating-nuclides210Pb and226Ra

Lead-210 is often used to date recent (100 y) environmental samples. Three different methods for its determination are compared:²¹⁰Pb -counting with a low level proportional counter,²¹⁰Pb -spectroscopy and²¹⁰Po -spectroscopy. Agreement within analytical errors was found for the three methods in two sediment cores from Lake Zurich, Switzerland and in IAEA SD-A-1 deep sea reference material. For²¹⁰Po -spectroscopy, the detection and determination limit is an order of magnitude lower than these for the other methods. Methods for the determination of²²⁶Ra are also discussed. Measurements on low level proportional counters are difficult to interpret and not suitable for routine work. A better way to measure²²⁶Ra is -spectroscopy of colloidal Ba(Ra)SO₄.     

A new analytical approach for 226Ra and 228Ra in environmental waters

The concentration of Ra isotopes in environmental water can be determined from the amount of Ra isotopes recovered in two successive batch operations a using cation exchange resin. The present analytical method is applicable to 10 liter of sample water having a Ra concentration larger than 10 mBq/l and is also applicable to the ordinary underground water of less than 1 mBq/l by use of 50 liter of sample water. In case where Ra concentration is extremely low, Mn-impregnated acrylic fiber can be used with a larger volume of water sample as an absorbent by soaking it in the water.     

Radioanalytical methods for the accurate determination of227Ac and228Th in irradiated226Ra targets

Alpha spectrometry is proposed for the quantitative analysis of²²⁷Ac and²²⁸Th in irradiated²²⁶Ra targets. The chemical separation and the radiochemical determination is described.