Tritium activity levels in drinking water of Adana,Turkey

Tritium activity in potable drinking water samples from Adana city were measured using liquid scintillation counting after distillation procedure. The results exposed that the activity concentrations of the tritium measured in one-third of these samples were lower than minimum detectable activity which has a value of 2 Bq/L for counting time of 1,500 min. However, the maximum and mean value of the tritium activity was found to be 9.1 Bq/L (77.3 TU) and 7.0 Bq/l (59.4 TU), respectively. These values were substantially below the 100 Bq/L which is normative limit in Turkey for waters intended for human consumption. The highest values of annual effective dose received by infants, children and adults due to measured tritium activity were estimated as 0.041, 0.057 and 0.120 μSv/y, respectively.     

Determination of 36Cl in biological shield concrete using pyrohydrolysis and liquid scintillation counting

A method for the determination of 36Cl in biological shield concrete of nuclear reactors was developed. Cl in the concrete sample was extracted quantitatively by pyrohydrolysis at 900 degrees C and recovered in Na2CO3 solution for subsequent measurement of 36Cl by liquid scintillation counting. WO3 was used as an accelerator in the pyrohydrolysis. The Cl extraction procedure was optimized by investigating experimental conditions with the use of ion chromatography and its recovery was evaluated by the analysis of the geochemical reference samples. The detection limit of 36Cl was 0.02 Bq g(-1) for a sample weight of 2 g. The relative standard deviation was 3-7% for the samples containing 0.5 Bq g(-1) levels of 36Cl. The method was applied to determine 36Cl in biological shield concrete of the Japan Power Demonstration Reactor.     

Development and validation of Ni–Ni electrolytic enrichment method for tritium determination in samples of underground waters of Jeju Island

A method of tritium electrolytic enrichment was developed, optimized and validated. The enrichment parameters were compared with different current and total current charge variation and tritium separation factor was from 8 to 36 with a current density variation. The detection limit of tritium measurement is about 0.5 TU using 1,000 mL sample and 600 min counting time. Several samples of groundwaters were processed in our and another laboratory with good agreement of results within 15% deviation. Developed and validated method of tritium determination was applied groundwaters in Jeju Island with a liquid scintillation counter (LSC) and electrolytic enrichment method using Ni–Ni electrodes. The tritium concentrations in fifty eight groundwaters in Jeju Island were ranged <0.5 TU-3.9 TU and averaged value was 2.12 TU.     

Methodology for rapid tritium determination in urine

Summary The present work proposes a methodology for a rapid determina-tion of the tritium content in urine. The urine is treated with active carbon and tritium is determined by liquid scintillation counting. Different kinds of active carbon were experimented for the metabolites removal from urine samples. The counting efficiency was calculated by a quench curve using yellow food dye as a quenching agent. It was obtained a procedure which maintained a good reproducibility, low uncertainty and detection limit of 7 Bq/l (10 ml of urine, 120 minutes of counting time and efficiency of 23.9%).     

Effect of chemical quenching on background counting rate in tritium channel of a large volume liquid scintillation counter

Background counting rate in tritium channel of a large volume liquid scintillation counter increased with water content ranged 0 to 50% of liquid scintillator. This phenomenon can be explained as follows: The height of scintillation pulses of Compton electrons induced by background gamma radiation is lowered by chemical quenching and shifts to tritium channel. The background counting rate in tritium channel showed a linear relationship with external standard channel ratio of background samples. This relationship is applicable to determine the correct background counting rate for quenching samples and to achieve higher precision of tritium measurement.     

Ultraviolet photolysis of urine for suppression of color quenching prior to liquid scintillation counting of tritium

In order to reduce the color quenching in the measurement of tritium in urine by liquid scintillation counting , UV irradiation was applied to decompose the organic substances in the sample. Urine was decolorized under UV irradiation in the presence of hydrogen peroxide. As a result, color quenching was considerably suppressed and higher counting efficiency of tritium was obtained. This UV treatment made it possible to increase the urine content in the sample from 2 to 40% (v/v) without significant decrease of counting efficiency. Either higher sensitivity or shorter analysis time was achieved in the tritium measurement by the augmentation of urine content. When the measurement time was 30 min, the detection limit of tritium defined as 3s was 0.03 Bq/ml. At the expense of some sensitivity (set at a detection limit of 0.3 Bq/ml), the measurement time was shortened to 0.5 min. These results will make a great improvement to routine tritium monitoring as well as to emergency monitoring in mass tritium exposure.      

Field deployable tritium analysis system for ground and surface water measurements

Researchers from the Savannah River Technology Center, the Center for Applied Isotope Studies (CAIS) and Sampling Systems have developed a prototype Field Deployable Tritium Analysis System (FDTAS) for near-real-time measurements of environmental levels of tritium in ground and surface water. The device consists of a modified liquid scintillation counter coupled to an automatic sampler which incorporates on-line water purification. The FDTAS has been field tested at several Savannah River Site locations and has produced results comparable to laboratory analyses for low concentrations of tritium. Figures of merit obtained in the field include an average tritium background count rate of 1.5 counts per minute (cpm), tritium detection efficiency of ≈25%, and a detection limit of <10 Bq/l for a 100 minute count.     

Levels of tritium concentration in the environmental samples around JAERI TOKAI

By the operation of research reactors, tritium-handling facilities, nuclear power plants, and a reprocessing facility around JAERI TOKAI, tritium is released into the environment in compliance with the regulatory standards.To investigate the levels of tritium concentration in environmental samples around JAERI, rain, air (vapor and hydrogen gas), and tissue-free water of pine needles were measured and analyzed from 1984 to 1993. Sampling locations were determined by taking into consideration wind direction, distance from nuclear facilities, and population distribution. The NAKA site (about 6 km west-northwest from the TOKAI site) was also selected as a reference point.Rain and tissue-free water of pine needles were sampled monthly. For air samples, sampling was carried out for two weeks by using the continuous tritium sampler. After the pretreatment of samples, tritium concentrations were measured by a low background liquid scintillation counter (detection limit is 0.8 Bq/l).Annual mean tritium concentrations in rain observed at six points for 10 years was 0.8 to 8.9 Bq/l, which decreased with distance from the nuclear facilities. Tritium concentrations in rain obtained at Chiba City were around 0.8 Bq/l (1987–1988) and those at the NAKA site were 0.8 to 3.8 Bq/l.Annual mean HTO concentrations in air at three points for 10 years were 9.2×10^–2 to 1.1 Bq/m³, although HT concentrations in air, ranging from 1.7×10^–2 to 5.8×10^–2 Bq/m³, were not influenced by the operation of the nuclear facilities.Annual mean tritium concentrations in tissue-free water of pine needles at four points for 10 years were 1.4 to 31 Bq/l. Those at the NAKA site ranging from 1.4 to 6.2 Bq/l were in good agreement with the reported value by Takashima of 0.78 to 3.0 Bq/l at twenty-one locations in Japan.Monthly mean HTO concentrations in air for 10 years showed a good correlation with absolute humidity, while other samples showed no seasonal variation.Higher level tritium concentrations in rain, in air (vapor), and in tissue-free water of pine needles at the TOKAI site were caused by the tritium released from the nuclear facilities.The committed effective dose equivalent to the member of general public, estimated using the maximum tritium concentration in air (1.1 Bq/m³), was 0.23 Sv, which was about 1/4000 of dose limit for general public.     

Experimental investigation on tritium gettering with hydrogen uranyl phosphate (HUP)

At room-temperature and atmospheric pressure, using electrode disks of various sizes, under the action 4 7Vdc eletric field, we gettered tritium gas from 2.2L of air containing (0.15 18.61)×10⁸ Bq of tritium and (3000 12000) ppm of moisture during 50 hours or so the efficiency of gettering tritium was over 95%. Applying liquid scintillation counting method, we measured the tritium in the disks after gettering, and found that the amounts of tritium in the disks were equal to those reduced in the tested tritiated air.     

Neutron activation analysis of low level lithium in water samples

For determining low level lithium concentrations in water, a neutron activation method based on the measurement of tritium radioactivity produced by⁶Li(n,)³H reaction has been developed. This method is specific and free from interference by other chemical elements. Using a low background liquid scintillation counter for tritium measurement, the detection limit is approximately 0.3 ppm during irradiation at a thermal neutron flux density of 1.1·10⁷n·cm^–2·s^–1 for 6 hours by a small nuclear reactor and liquid scintillation counting for 2000 minutes     

Efficiency of tritium enrichment by electrolytic cell with multi-nickel-plates electrode and its application to the determination of tritium in environmental water

For the purpose of speeding up the tritium enrichment by electrolysis, we have produced an electrolytic cell with the multi-plate-electrode system instead of the commonly used single-plate-electrode, and examined the efficiencies for the tritium enrichment under the conditions of different current densities and electrode gaps. From the results, the tritium recovery and the separation factor beta were found to be maximized under the condition of 70 mA/cm2 of current density and 1.6 mm of electrode gap, and they were 90 percent and 23, respectively. Using this cell, it took 28 hours to reduce 100 ml of a sample water to 10 ml, and took 2 days, including the time required for other operations, to determine the tritium concentration of 1.85 Bq/l (50 pCi/l) with the counting error of within +/- 10 percent. This method has been applied to determining the tritium concentrations of environmental samples from Yamato River region during July 1981-February 1983. They were in the range of 1.11-9.48 Bq/l (30-256 pCi/l).     

Radioactivity in deuterated compounds

Commercially available D₂O and deuterated toluene have been measured with a liquid scintillation spectrometer and were found to contain 2.71–6.15 Bq of tritium in 1 ml of D₂O, and 1.10 Bq of tritium in 1 ml of deuterated toluene.     

Radon measurement in carbonated water with the Lucas cell and charcoal adsorption methods

There have been developed several different methods for measuring radon concentration in water which are now widely used, such as: liquid scintillation counting, Lucas cell counting, gamma and alpha spectroscopy. However, as far as the radon measurements in carbonated water are concerned, there are some issues caused by the gas excess. The aim of our work was to develop a simple method for measuring radon concentration in carbonated water that can be used for in situ measurements. Nevertheless, we propose not one, but two methods for measuring radon concentration in carbonated water. Thus, the first one is based on Lucas scintillation cells, and can be used for on-site measurements, while the second one utilizes activated charcoal adsorption, and needs a setup laboratory for gamma spectrometry measurements. For the evaluation of the methods, we compared the results of the Lucas cell-Luk3C method and of the activated charcoal method, both for non-carbonated and carbonated water. The simplest method for radon concentration determination—Lucas cell method—was successfully applied to fourteen natural carbonated water samples from Borsec to Bilbor area. The radon concentrations obtained ranged from 5.6 ± 0.5 to 39.6 ± 4.0 Bq/L, with a mean of 15.9 ± 2.6 Bq/L, these values are lower than 100 Bq/L, the maximum value recommended by the World Health Organization.     

Determination of131I in soil using a liquid anion exchanger and liquid scintillation technique

A simple method for rapid determination of¹³¹I in soil is described. The method is based on the specific separation and concentration of radioiodine from the soil extract with a liquid anion exchanger and measuring its radioactivity with liquid scintillation counting. The¹³¹I from soil is extracted with aqueous solution of sodium hydroxide. The method permits the determination of¹³¹I with a lower limit of detection less than 0.1 Bq/10 g of soil.     

Magnetic solid‐phase extraction or dispersive liquid–liquid microextraction for pyrethroid determination in environmental samples

The determination of 15 pyrethroids in soil and water samples was carried out by gas chromatography with mass spectrometry. Compounds were extracted from the soil samples (4 g) using solid–liquid extraction and then salting‐out assisted liquid–liquid extraction. The acetonitrile phase obtained (0.8 mL) was used as a dispersant solvent, to which 75 μL of chloroform was added as an extractant solvent, submitting the mixture to dispersive liquid–liquid microextraction. For the analysis of water samples (40 mL), magnetic solid‐phase extraction was performed using nanocomposites of magnetic nanoparticles and multiwalled carbon nanotubes as sorbent material (10 mg). The mixture was shaken for 45 min at room temperature before separation with a magnet and desorption with 3 mL of acetone using ultrasounds for 5 min. The solvent was evaporated and reconstituted with 100 μL acetonitrile before injection. Matrix‐matched calibration is recommended for quantification of soil samples, while water samples can be quantified by standards calibration. The limits of detection were in the range of 0.03–0.5 ng/g (soil) and 0.09–0.24 ng/mL (water), depending on the analyte. The analyzed environmental samples did not contain the studied pyrethroids, at least above the corresponding limits of detection.     

Polypyrrole‐coated alginate/magnetite nanoparticles composite sorbent for the extraction of endocrine‐disrupting compounds

Magnetite nanoparticles incorporated into alginate beads and coated with a polypyrrole adsorbent were prepared (polypyrrole/Fe₃O₄/alginate bead) and used as an effective magnetic solid‐phase extraction sorbent for the extraction and enrichment of endocrine‐disrupting compounds (estriol, β‐estradiol and bisphenol A) in water samples. The determination of the extracted endocrine‐disrupting compounds was performed using high‐performance liquid chromatography with a fluorescence detector. The effect of various parameters on the extraction efficiency of endocrine disrupting compounds were investigated and optimized including the type and amount of sorbent, sample pH, extraction time, stirring speed, and desorption conditions. Under optimum conditions, the calibration curves were linear in the concentration range of 0.5–100.0 μg/L, and the limit of detection was 0.5 μg/L. The developed method showed a high extraction efficiency, the recoveries were in the range of 90.5 ± 4.1 to 98.2 ± 5.5%. The developed sorbent was easy to prepare, was cost‐effective, robust, and provided a good reproducibility (RSDs < 5%), and could be reused 16 times. The developed method was successfully applied for the determination of endocrine‐disrupting compounds in water samples.     

Removal of the impurities from environmental water samples for tritium measurement by liquid scintillation counting

Liquid scintillation counting is the most popular method for tritium measurement, however, it takes much time and a lot of doing to distill off the impurities before mixing the sample water and liquid scintillation cocktail. We have investigated the possibility of an alternative method to the distillation. We have found out that the filtration can be an alternative to distillation for the environmental water samples before electrolytic enrichment.     

Optimisation of liquid scintillation counting conditions for rapid tritium determination in aqueous samples

Several studies were carried out to optimise rapid tritium analysis in fresh waters by ultra-low background liquid scintillation. These included the optimisation of (1) sample/scintillant ratio, (2) pulse shape analysis, and (3) pulse-amplitude comparator, and studies concerning (1) the combination scintillant/vial and (2) the effect of chemiluminescence. The proposed method involves the mixing of 8 ml sample with 12 ml scintillation cocktail Ultima Gold AB in Zinsser low diffusion vials. These are stored during one day before counting in order to reduce chemiluminescence. The minimum detectable activity achieved was 2.2 Bq·l⁻¹ for a total counting time of 360 minutes. In order to test the method, tritium was determined in Ebro river samples.     

Radon and tritium measurements in drinking water in a region of central Italy (Umbria)

Summary In the last years the interest in drinking and mineral water radioactivity has grown. Recently national and EU regulations replaced the previous drinking water norms with the aim to strengthen consumers security concerning drinking water quality. Perugia and Urbino Universities carried out a joint study on the radiological characterization of the water destined for human consumption in the Umbria region. The aim of this work was to produce a map of the radon and tritium concentrations in the water of this area as a basis for the implementation of hydrogeological knowledge and to determine a possible related radiological risk for the local population.²²²Rn measurements were performed by liquid scintillation and gamma-spectrometry and³H measurements by liquid scintillation. Up to now, the²²²Rn concentrations ranged 5.9-65.79 Bq/l and³H concentrations are always lower than the detection limit (8.6 Bq/l).