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The hydrogen radioactive isotope, tritium, not only reflects seasonal variation in precipitation but also variations on a local level. To use this radioisotope in authentication and geographical indication procedures, the tritium levels in vines, grapes, and wine were measured in two forms: (1) tissue-free water tritium (TFWT), measured in the free water of the plant or the aqueous phase of the wine; (2) organically bound tritium (OBT), measured in the organic part of the plant or wine (as ethanol). This paper presents the tritium behavior in vines from May to October and in the wine produced from harvested grapes for both tritium forms (TFWT and OBT) in connection with environmental tritium concentrations in air and precipitations during the 2019–2023 vegetation periods near the Râmnicu Vâlcea city. If the tritium of tissue-free water was influenced by precipitation and air humidity during the harvest period, the organically bound tritium recorded a maximum level with a delay of 1–2 months compared with tritium’s seasonal variation in precipitation and air. The tritium values of early mean in precipitation and ethanol from wine were approximately an average value of 11 TU for all 5 years of observations.

The relevance. One of the relatively long-lived nuclear fission products is 151Sm (T1/2~90 years). The total cumulative yield of 151Sm upon fission of the isotopes 235U, 239Pu and 238U is 0,46, 1,29 and 0,83 %, respectively. The estimated amount of 151Sm that could have been dispersed during ground and atmospheric tests at Semipalatinsk test site is 6,1·105 Ci. The current situation with the levels of radioactive contamination of the soil cover with this radionuclide is still unknown. The aim of the research is to develop the method for radiochemical determination of 151Sm in Semipalatinsk test site soils using liquid scintillation spectrometry. Objects. Surface soil samples were taken from the territory of the former Semipalatinsk test site. The main sampling criteria were the presence of 137Cs as a possible indicator of the presence of 151Sm and the absence of radioactive isotopes of Eu as the main interfering radionuclide. The specific activity of 137Cs in the samples under study varied from 3,6 to 780 Bq/kg. Methods. The proposed method for 151Sm determination includes complete dissolution of the samples with concentrated acids (HF and HNO3 and their mixtures), isolation and radiochemical purification with ion exchange resins, as well as precipitation of poorly soluble substances. In order to determine the chemical yield, 0,5 mg of Sm-carrier was added to each sample as an indicator. The quenching curve for 151Sm was prepared using the CIEMAT/NIST approach. The 151Sm specific activity was measured using Quantulus 1220 LSC. Results. The radiochemical purification of the 151Sm fraction from interfering beta emitters was analyzed and evaluated, as well as the effect of natural samarium on the chemical yield. The contribution of natural samarium regarding to the clarke does not exceed 8 % (for 5 g soil sample), and in relation to the experimentally measured amount – 0,5 %. However, it seems more expedient to double the amount of the added carrier (up to 1 mg per sample), which will reduce the contribution of natural samarium to 4 % (relative to the clarke). Gamma-spectrometric measurements of the isolated samarium fraction indicate the possibility of its contamination with some residual amount of strontium isotopes (85Sr was used as an indicator), the maximum amount of which, obviously, does not exceed 5 %. The specific activity of all other considered radionuclides is below the detection limits. MDA value obtained for 151Sm in this work was in the region of 0,01 Bq/g. The mean chemical recovery of 151Sm was 83 %. The specific activity of 151Sm in surface soil ranged from 158 to 290 Bq/kg.

Objective: To figure out the source of uncertainty in the determination of 14C activity concentration in urine samples, and to establish a complete expression of analysis results, in order to improve the accuracy of 14C monitoring method. Methods: Four urine samples of normal people were collected, and wet oxidation method was used in the pretreatment of the samples, then the activity concentration of 14C was determined by liquid scintillation counting (LSC). After the mathematical model was established, the uncertainty components were determined, the standard uncertainty was combined, and the extended uncertainty was calculated. Results: The relative uncertainty of 4 samples was 22.5%, 17.0%, 17.3% and 18.2%. The activity concentration of urine was (0.32 ​± ​0.14), (0.60 ​± ​0.20), (0.86 ​± ​0.30) and (0.74 ​± ​0.27) Bq/L, respectively. In the relative uncertainty of 22.5%, 17.7% was from sample counting, 13.6% from detection efficiency, 2.1% from recovery rate, 0.58% from sample volume, and 0.01% from sample weight. Conclusions: The main factors affecting the uncertainty include the error or deviation of sample counting, detection efficiency and recovery rate. The error of volume and weight also contributes to the measurement uncertainty.

Consumption and drinking of healthy and high-quality water is considered an important matter in human life, so monitoring of drinking water pollution including radioactive contamination and assessing the amount of radiation exposure of people through water consumption is very important. The purpose of this investigation was to measure the concentration of gross beta and alpha activities in water samples collected from Tehran water sources. In the present study, the gross beta and alpha activity concentrations of 35 water samples in Tehran were analyzed and measured to evaluate their radiological quality using liquid scintillation method. The results of the analysis showed the activity concentration of gross alpha ranges from 48 mBq/L to 227 mBq/L with a mean of 137.5 mBq/L. the activity concentration of gross beta in the samples ranged from 49 mBq/L to 328 mBq/L with a mean of 184.7 mBq/L. Also, the correlation coefficient between the results were very strong and equal to 0.87. The results showed that the gross beta and alpha activity concentrations in all waters was lower than the standard limit of the World Health Organization (WHO) and the Institute of Standards and Industrial Research of Iran, which is 500 mBq/L and 1000 mBq/L, respectively and also waters are radiologically healthy.

The approach taken in the WHO Guidelines for controlling radiological hazards in public water supplies has two stages. The first is an initial screening for gross alpha and beta activity to determine whether the activity concentrations are below levels at which no further action is required; and if these screening levels are exceeded, investigation of the concentration of individual radionuclides and comparison with specific guidance levels. Mineral water is obtained directly from natural sources or by extracting groundwater, it is characterized by the quantity of mineral salts, trace elements and other constituents. The bottled water industry is present in the major regions of the world, and the population consumption has increased every year in Brazil and world, also increasing new mineral water mining sites, so it is necessary to constantly check the amount of radioactivity in mineral water. The aim of this study is to quantify the concentration of the natural radionuclides in the bottled mineral water consumed in São Paulo city. The bottled mineral water samples were purchased in a supermarket in São Paulo, with 23 different brands. The determination of gross alpha and beta activity concentration in bottled mineral water by Liquid Scintillation Counting measurement was performed using a 1220 Quantulus™ Ultra Low-Level Liquid Scintillation Spectrometer. The natural radionuclides (226Ra, 228Ra, 210Pb and 40K) were measured by gamma spectrometry, using an HPGe detector. The results obtained in this study can be used for a database on bottled mineral water radioactivity from Brazil.

In this paper, the evaluation of the Rn-222 radioactivity content in drinking water samples from the Calabria region, southern Italy, is reported as a case study. The Rn-222-specific activity in the analyzed groundwater samples for human use was evaluated by using the PerkinElmer Tricarb 4910 TR setup and compared with the parameter value (100 Bq L−1) reported in the reference Italian legislation, i.e., D.Lgs. 28/2016, derived from the European Directive 2013/51/Euratom. The radiological health risk for the population of the investigated area, due to the ingestion and inhalation of Rn-222 dissolved in water, was then evaluated by calculating the total annual effective dose, only in those cases where the parameter value was exceeded. The obtained results represent a main reference for the investigated area and are useful for determining any possible radiological health risk for human beings related to the ingestion of the investigated radionuclide. Moreover, they can also be used as a baseline for future investigations regarding background radioactivity levels.

Non-linear curve fitting of tracer efficiency is one of the uncertainty contributors in CIEMAT/NIST method for specific activity measurement and half-life evaluation of radionuclide. This study applied least squared fitting of four different polynomials to validate the tracer efficiency calibration curve for the specific activity measurements of nine Potassium Chloride samples from which half-life and decay constants were computed. All samples were measured using TR1000 Liquid Scintillation Counter and the results of the relative standard uncertainties in tracer interpolated efficiencies associated with the least square fit analysis were found to be 8.363%, 8.076%, 7.941% and 8.767% for polynomials of n = 2, n = 3, n = 4 and n = 5, respectively. The corresponding values of 40 K specific activity, from the application of empirical efficiencies generated with these polynomials were found to be (16.541, 16.540, 16.537 and 16.548) Bq/g respectively. From these measured specific activity values, the computed half-life and decay constants were found to be (1.2518, 1.2519, 1.2521 and 1.2513) ×109 y (for n = 2, n = 3, n = 4, and n = 5), respectively, and (5.365, 5.5364, 5.5354 and 5.5391) ×10-10 y-1 respectively. All values were found to be in good agreement with results of other literatures. However to minimize uncertainty associated with empirically generated tracer interpolation efficiencies, least squared fit analysis of tracer calibration curve should be done, with control trials using different polynomials so as to obtain the best fit.

In decommissioning of nuclear facilities the presence of activated steel requires the determination, along with other radionuclides, of 55Fe and 63Ni. These can be considered as hard-to-measure-radionuclides because of their low energy beta particles or X radiation emitted. Furthermore, those radionuclides are usually mixed with a relevant fraction of non-radioactive Fe and Ni. This implies that, in those cases involving very low radioactive samples close to background activity level, a significant mass of steel sample must be physically and chemically treated and analyzed to achieve the Minimum Detectable activity Concentration (MDC) required by the Authority for clearance purposes. Due to colour quenching the acquisition time is particularly long. Minimizing the colour effect is therefore important for laboratories that must perform many determinations in a reasonable time, achieving the MDC in accordance with the Authority requests. For this reason, the choice of solvent can be an important information to save analyses time. The intensity of the colour quenching is, in fact, strongly dependent on the type of acid used to solubilize the sample before the mixing with the liquid scintillation cocktail. Some types of acid can even increase the phenomenon while others can drastically reduce such an effect. The aim of this work is to offer, through a correlation study between sample concentration in the LSC vial and type of solvent used in dilution, a reliable method for quantifying 63Ni and 55Fe in steel samples with very low activity, close to the background level.

In the decommissioning of nuclear facilities, it is necessary to assess the radioactivity inventory for waste classification and management. For nuclear fusion experiments or accelerator-driven neutron sources, the main contribution to the radiological inventory comes from activation products and tritium. When water is used as coolant of components, it may be activated by neutrons with the consequent production of tritium, and short-lived oxygen and nitrogen isotopes. In most cases several chemical elements may be in solution or suspension in water, because of metallic pipes corrosion when occurring, or functional reasons, e.g. chemical conditioning, addition of antifreeze agent, etc. In this case other activation products could be present and need to be characterized. In this case study, a sample of the coolant of the ENEA Frascati Neutron Generator (FNG) has been radiologically, chemically and physically characterized. In such a facility, during the operation, a beam of deuterons is accelerated up to 300 keV and impacts on a tritiated target for producing 14 MeV neutrons exploiting the fusion reaction T(d,n)α. To avoid overheating in the area around the target, a water-cooling loop is used. After several years of operation, a sample of the fluid has been extracted to undergo a qualitative and quantitative analysis of the radionuclides inventory. Gamma spectrometry has not shown any presence of gamma emitters. On the other hand, Liquid Scintillation Counting (LSC) has provided evidence of the presence of beta emitters. It is known that tritium is expected to occur in the sample because of releases from the tritiated titanium target. This work concerns the development of a method to discriminate the tritium contribution with respect to the total beta activity within the FNG coolant. Since it is known that an unspecified percentage of an unknown anticorrosive agent was added to the water coolant, vacuum distillation has been used to extract purified water (containing only tritium) from the coolant sample leaving any (activated) non-volatile compound in the undistilled fraction. After distillation, any fraction has been investigated by Raman spectroscopy, to determine: a) the chemical composition of the colored anticorrosive agent, b) the efficiency of the separation. Afterwards, both fractions have been analysed by means of LSC, and results showed that the main contribution to sample activity is due to tritium and the activity values are consistent with the theoretical H atomic concentration in both fractions.

Background55Fe is a low-energy radionuclide that is difficult to measure and decays to a ground state of 55Mn through pure electron capture (EC), accompanied by the emission of Auger electrons and low-energy X-ray. As iron is the main component of nuclear reactor building materials, significant amounts of 55Fe have been produced in nuclear reactors and other neutron-producing nuclear facilities.PurposeThis study aims to develop an 55Fe nuclide standard through the absolute measurement of 55Fe activity and provides activity traceability services for 55Fe measuring instruments to ensure the accuracy and consistency of the measurement results of calibration instruments.MethodsThe liquid scintillation triple-to-double coincidence ratio (TDCR) method was applied to determining the activity of 55Fe. First, based on nuclear and atomic data of 55Fe, the electron deposition spectrum of 55Fe in a scintillator was calculated using a random atomic rearrangement model. Second, the counting efficiency of single-energy electron was computed based on the free parameter model. The total efficiency curve of 55Fe was then obtained by summing the efficiency of all deposited electrons. Finally, the experimental counting efficiency was derived by measuring the TDCR value and combining it with the total efficiency curve to realize an absolute measurement of 55Fe activity.ResultsThe experimental results show that correction factors for the asymmetric effect of photomultiplier tube (PMT) quantum efficiency obtained on test samples are between 1.001 and 1.005. The measured specific activity of 55Fe is 94.15 kBq∙g-1 with a relative standard uncertainty of 0.45%. Experimental efficiency is better than 63% for double coincidence logic sum of liquid scintillation counter.ConclusionsThis study demonstrates that low relative standard uncertainty of 55Fe activity could be achieved using the liquid scintillation TDCR method with high detection efficiency, and more consistent measurement results can be obtained after applying the asymmetry correction of PMT quantum efficiency.

An evaluation of various radiometric methods to analyze 226Ra in water has been employed on a set of 10 standard solutions of different concentrations in the range of 1–10 Bq/L−1. The analysis was carried out using well-established procedures by means of gamma-ray, alpha-particle and liquid scintillation spectrometry. The feasibility of the various methods has been quantified in terms of relative standard error and percentage error. Correlations between the various methods have been presented and discussed. In general, good agreement was found in the results of various methodologies, which assures the accuracy of the methods and allows for the validation of instrumentation and procedures. Of the different methods adopted here, a combined procedure for the determination of 226Ra along with 228Ra using Quantulus 1220 ultra-low level background liquid scintillation counting gave the most accurate results.

Kinetic isotope effects (KIEs) are a very powerful tool for investigating enzyme mechanisms. Precision of measurement is the most important factor for KIE determinations, especially for small heavy atom KIEs. Internal competition is commonly used to measure small KIEs on V/K. Several methods, including such as liquid scintillation counting, mass spectrometry, nuclear magnetic resonance spectroscopy and polarimetry have been used to determine KIEs. In this paper, which does not aspire to be an exhaustive review, we briefly review different experimental approaches for the measurement of KIEs on enzymatic reaction with an emphasis on newer techniques employing mass spectrometry and nuclear magnetic resonance spectrometry as well as some corresponding examples.

We investigated the interference of radiolead in the isolation of radiostrontium using a strontium-specific resin by means of 85Sr and 212Pb radiotracers. The resin was found to be almost equally specific for lead ions as well. Elution of Pb2+, however, was found to occur at very low acid concentrations (£0.02 M HNO3) of the elutant. Even with pure distilled water as the elutant, elution of lead cannot compete with strontium, due to the delayed elution dynamics caused by residual acid in the column. In contrast to strontium, which is eluted quickly from the column and almost quantitatively after 4 mL elutant (practically independently of the acid concentration of the elutant), lead is eluted with much delay and not completely after the 10 mL elution. The Eichrom method for the determination of radiostrontium in water proposes elution with 0.05 M HNO3, which was found extremely useful, because at such an acid concentration, no radiolead is eluted from the column and allows the production of a pure radiostrontium fraction which can be measured by liquid scintillation counting.

On a first attempt, the determination of 14C and 36Cl activity concentrations in basic operational waste (spent ion-exchange resins and perlite mixture), in decommissioning waste (construction concrete, sand, stainless steel and serpentinite) and irradiated graphite from the Ignalina NPP has been performed. The samples for measurement of the specific activity of 14C and 36Cl were obtained from the selected places, where the highest values of the dose rate and the activity concentrations of gamma emitters were found. The performed study of the total 14C and 36Cl activity concentrations was based on estimated chemical forms of 14C (inorganic and organic compounds) and 36Cl as Cl- ion. The tested methods used in this study were found to be suitable for estimation of activity concentrations of measured radionuclides.

The sambaquis are archaeological sites with remains of pre-historical Brazilian civilizations. They look like small hills containing different kinds of shells, animal and fish bones, small artifacts and even human skeletons. Since the sambaqui sites in the Rio de Janeiro state are younger than 6000 years, the applicability of CO2 absorption on Carbo-Sorb® and 14C determination by counting on a low background liquid scintillation counter was tested. The International Atomic Energy Agency standard reference material IAEA-C2 was used in order to standardize the method. Nine sambaqui samples from five different archaeological sites found in the Rio de Janeiro state were analyzed and 14C ages between 2100 and 3600 years BP were observed. The same samples were sent to the 14C Laboratory of the Centro de Energia Nuclear na Agricultura (CENA/USP) where similar results were obtained.

Radiochemical methods for the determination of long-lived radionuclides have been briefly reviewed. Developments in nuclear measuring techniques such as alpha spectrometry and liquid scintillation counting as well as in chemical separations have been comparatively evaluated.

An in vitro method is presented which measures valid, unidirectional uptake rates for lipids across the intestinal brush border. This method combines analysis by a newly devised, double isotope counting system for solubilized tissue with the use of a nonabsorbable marker to correct gross uptake determinations for contamination by adherent mucosal fluid. Of seven markers, only [3H]inulin measured adherent mucosal fluid volumes as much as 20% greater than the other markers. Diffusion of the nonabsorbable marker, as well as of the compound being studied, into the unstirred layer made the time course of uptake critically important. The time lag for diffusion of marker invalidates the use of 1-min incubation periods; however, a linear time course of uptake that intercepts essentially at zero was found for taurocholate and octanoate for periods of from 2 to 5 min. Working within this critical time period with jejunum, it was shown that tissue dry weight was an appropriate measure of the amount of tissue and that uptake rates for taurocholic, octanoic, and lauric acids were linear with respect to concentration. Tissue binding of compounds was not significant. The results demonstrate that careful use of the described method yields accurate measurement of unidirectional uptake rates of lipids across the brush border that are of critical importance in defining the characteristics of membrane penetration and the rate-limiting steps in fat and sterol absorption.

The fatty acids in lipid mixtures are adsorbed on dehydrated hydroxy-charged ion exchange resin, the other lipids are removed by washing with solvent, and the adsorbed fatty acids are released with quaternary ammonium base for counting. All manipulations are carried out directly in scintillation vials