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The incidence of "acid attacks" (vitreolage) is a global concern, with those affected often receiving lifelong medical care due to physical and psychological damage. The purpose of this study was to evaluate the effectiveness of several emergency skin decontamination approaches against concentrated (>99 %) sulphuric acid and to identify the effective window of opportunity for decontamination. The effects of four decontamination methods (dry, wet, combined dry & wet and cotton cloth) were assessed using an in vitro diffusion cell system containing dermatomed porcine skin. Sulphuric acid (H 2 SO 4) was applied to the skin with decontamination protocols performed at 10 s, 30 s, 8 min, and 30 min post exposure. Skin damage was quantified by tritiated water (3H 2 O) penetration, receptor fluid pH and photometric stereo imaging (PSI), with quantification of residual sulphur (by SEM-EDS) to determine overall decontamination efficiency. Skin translucency (quantified by PSI) demonstrated a time-dependent loss of dermal tissue integrity from 10 s. Quantification of dermal sulphur content confirmed the rapid (exponential) decrease in decontamination efficiency with time. The pH of the water effluent indicated complete neutralisation of acid from the skin surface after 90 s of irrigation. Wet decontamination (either alone or immediately following dry decontamination) was the most effective intervention evaluated, although no decontamination technique was statistically effective after 30 s exposure to the acid. These data demonstrate the time-critical consequences of dermal exposure to concentrated sulphuric acid: we find no practical window of opportunity for acid decontamination, as physical damage is virtually instantaneous. • Response to an acid exposure requires rapid intervention. • Immediate flushing with water reduces skin damage, other methods exacerbate damage. • Effectiveness of washing deteriorates as soon as 30 s following exposure to acid. [ABSTRACT FROM AUTHOR]

The treatment of tritiated water(HTO) produced during the operation of nuclear power plants involves the challenging process of H2O/HTO separation, for which non-radioactive H2O/HDO separation is usually used as a research model in laboratories. Recently, membrane distillation processes based on multi-layered graphene oxide membranes showed good performance for H2O/HDO separation, but further improvement still need developing novel membrane materials or structures. In view of this, mono-layered graphene oxide nanoplatelets with different lateral sizes were utilized to prepare PTFE supported graphene oxide composite membranes for H2O/HDO separation in membrane distillation:(1) two types of mono-layered graphene oxide nanoplatelets with different lateral sizes were chosen to investigate the impact of lateral size of mono-layered graphene oxide nanoplatelets on the performance of H2O/HDO separation. The graphene oxide membrane based on GO nanoplatelets with the smaller lateral size gives the permeation flux of 0.944 L/(m2·h) and the separation factor of 1.043, and its overall separation performance is higher than that of graphene oxide membrane obtained with the larger lateral size of graphene oxide nanoplatelets; (2) mono-layered graphene oxide nanoplatelets with different lateral sizes were mixed in various mass ratios for the combination of their structural characteristics to prepare composite membranes. When the mixing mass ratio of the two sizes of graphene oxide nanoplatelets is 1:1, the resultant graphene oxide membrane exhibits permeation flux of 0.806 L/(m2·h), higher than that of the graphene oxide membrane prepared with the larger lateral size, and the separation factor of these two membranes is similar; (3) mono-layered graphene oxide nanoplatelets with the larger lateral size were etched to introduce in-plane pores. The resulted GO membrane gave enhanced H2O/HDO separation performance. These results demonstrate that the lateral size of mono-layered graphene oxide nanoplatelets can affect the performance of corresponding membranes for the separation of H2O/HDO in membrane distillation, and the membranes based on mono-layered graphene oxide nanoplatelets with smaller lateral size or mono-layered graphene oxide nanoplatelets with different lateral sizes mixed in a certain ratio has better performance for the separation of H2O/HDO in membrane distillation. Moreover, the separation performance of H2O/HDO in membrane distillation can also be improved by introducing in-plane pores to graphene oxide nanoplatelets. Therefore, this work can guide the development of novel membrane materials or structures to achieve better H2O/HDO separation performance in membrane distillation and provide solutions for the treatment of radioactive wastewater containing tritiated water.

Background: The in vitro permeation test (IVPT) using exvivo human skin is a sensitive and robust model system that has been vital in elucidating the fundamental parameters surrounding the absorption of both therapeutic agents and industrial chemicals through skin. FDA and OECD IVPT Guidances recommend that each skin section selected for study should be screened prior to use to ensure that the stratum corneum integrity is retained. Three methods are currently considered acceptable: 1) transepidermal water loss (TEWL), 2) electrical resistance, and 3) tritiated water (3H2O) absorption. Methods: A retrospective analysis of data from the authors' laboratory has been performed with the objective of addressing a number of questions regarding the 3H2O and TEWL integrity tests, and the population attributes of a large database consisting of 17,330 individual skin sections obtained from 459 skin donors. The applicability and usefulness of these tests, when compared to companion permeation data obtained from 25 topical drug products, has also been examined. Results: Both integrity tests found water permeability to be equal in White and Hispanic races but higher than in Blacks, 3H2O being more discriminating than TEWL. Male skin is more permeable than female and there is a slight decrease in permeability with advancing age in both groups. Correlation between 3H2O absorption and drug absorption revealed a minimal relationship between the two in most cases, the Pearson correlation coefficient ranging from -0.417 to 0.953. Additionally, drug outliers were not always identified with a failing integrity test. Conclusion: The results call for a critical reexamination of the value of the 3H2O integrity test, and by extension, TEWL, for use in IVPT studies. [ABSTRACT FROM AUTHOR]

The processes of phase formation enabling the separation of water isotopologues in their solutions are studied and the physicochemical factors facilitating the extraction of heavy-water isotopologues are identified. The thermodynamic conditions for obtaining heavy water and heavy-oxygen water, as well as the optimal raw-material sources for their production, are determined. The productivity of the application of tritiated water, involving its electrosonolysis with the release of molecular tritium, is justified. [ABSTRACT FROM AUTHOR]

Large amounts of tritiated water (HTO) will be produced during the operation of nuclear power plants and fusion devices, which is harmful to the environment and human due to its radioactivity and toxicity. So, the tritium concentration of tritiated water must be reduced to a very low value before discharge. Hydrogen-water isotope exchange reaction (H 2 + HTO→H 2 O + HT) based on palladium membrane reactor has been proposed to process tritiated water. However, a comprehensive study about the influence of operation parameters on the membrane reactor performance is insufficient, which is not conducive to the design of reactor in practical application. Moreover, the commonly used Pt/Al 2 O 3 or Ni/SiO 2 catalysts are not active for tritiated water dissociation, so the catalytic activity of these catalysts is not high. In order to process tritiated water more effectively, a two-stage membrane reactor has been designed and established in this work, and Pt/TiO 2 catalyst with rich oxygen vacancies is used to catalyze the hydrogen-water isotope exchange reaction for the first time. The membrane reactor performance shows an approximate linear relationship with a new combined parameter S 0.5 P 1.5 R / F 2 (S is membrane area, F is water flow rate, P is vapor partial pressure, R is swamping ratio), which can be used predict the membrane performance. The isotope exchange reaction activity of Pt/TiO 2 is better than that of Pt/Al 2 O 3 due to its good ability for water dissociation and the hydrogen spillover effect. At last, a tritiated water processing experiment by using two-stage membrane reactor with Pt/TiO 2 catalyst with rich oxygen vacancies has been carried out. The tritium decontamination factor reaches 40588, which is the highest experimental value so far. The results indicate that the two-stage Pd membrane reactor based on hydrogen-water isotope exchange reaction is an efficient technology for tritiated water processing. • A two-stage membrane reactor has been designed and established to process tritiated water. • The reactor performance shows an approximate linear relationship with a new combined parameter. • The catalytic activity of Pt/TiO 2 with rich oxygen vacancies is better than that of Pt/Al 2 O 3. • Tritium concentration of tritiated water can decrease by 4 orders of magnitude by using our reactor. [ABSTRACT FROM AUTHOR]

Nuclear sites require regular measurements of the air, soil, and groundwater to ensure the safety of the surrounding environment from potentially hazardous levels of contamination. Although high-energy beta and gamma emitters can often be detected instantly using fixed dosimeters, the detection of low-energy beta emitters is a difficult challenge, especially in groundwater, as its radiation is easily self-absorbed by the surrounding medium. Therefore, it is common practice to sample groundwater and transfer it to a laboratory for analysis using Liquid Scintillation Counting. This work demonstrates a new detector design for the real-time monitoring of tritiated water, a weak beta emitter. This design utilizes a flow cell filled with a granulated scintillator to maximize the surface area of the sample. The cavity is made from plastic sheets, which allow rapid manufacture using readily available lamination sheets. A column of SiPMs in coincidence counting mode has been implemented to reduce noise and allow future extensions to the flow cell for greater detection rates while allowing the detector to fit within limited spaces such as groundwater monitoring boreholes. Using multiple concentrations of tritiated water, this detector has been validated and calibrated, obtaining a minimum detection activity of 26.356 ± 0.889 Bq/mL for a 1-day counting period.

The distribution of tritium in the soil-vegetation complex was studied on a series of combined samples taken in the area of the radioactive waste storage facility (RWSF). It is shown that bioaccumulation of tritium by vegetation is determined mainly by the position of each specific object (testing point) in relation to the predominant direction of atmospheric transport of the nuclide. In locally selected samples of herbaceous and arboreal vegetation, the content of the nuclide changes according with a high degree of correlation, and its distribution in fractions of freely migrating (transpirational) tritiated water (TW) and in the form of organically bound tritium (OBT) also changes according with a high degree of correlation. In the zones of intense and persistent atmospheric migration tritium forms radiogeochemical anomalies in the soil and vegetation. Under the conditions of stationary atmospheric migration flows, pseudoequilibrium ratios of nuclide concentration in the components of the soil-vegetation system are established, while under the conditions of the functioning of short-term soil flows, the concentration equilibrium of the nuclide in the components of the soil-vegetation system is not observed. Higher concentrations of tritium are observed in more tightly bound forms in both soil and vegetation, which obviously reflects a large dynamic dependence of the mobile form on weather and climate conditions. The ratios of activity concentration of tritium in different forms of presence determined for different types of vegetation as concentration ratio (CR) indicate that tritium accumulates more effectively in arboreal plants - bushes, trees than in herbaceous ones (grass), it is equal to 1.10 and 1.20, respectively. Freely migrating (transpirational) tritiated water possibly due to greater mobility and greater dependence on changes in the activity concentration of tritium in the atmospheric plume and moisture saturation of the air, has a lower activity concentration of tritium than the organically fixed form (OBT), respectively 1.14 and 1.29, which does not have such temporal dependence. During the emission of tritium from RWSF there was a significant accumulation of the heavy isotope of hydrogen in an organically bound form, that is more than half of the tritium absorbed by vegetation is retained during the existence of organic matter and is temporally excluded from the biological cycle in the case of arboreal vegetation. In conditions of the forest landscape of the sanitary protection zone (SPZ) of the RWSF, root absorption of tritium by grass from the humus layer is from 20 to 31% of its total amount accumulated in the soil. The degree of absorption of tritium from the soil is almost the same in herbaceous and arboreal vegetation. This indicates that during the long-term existence of the atmospheric-radio-geochemical anomaly caused by the constant emission of tritium from the storage of RW in organic matter, an equilibrium balance of the content of transpirational HTO and OBT has been formed. In turn, the establishment of such a balance in plant matter can be used as an indicator of a prolonged regime of tritium emission from RWSF. Herbaceous and arboreal vegetation make it possible to determine the spatial position of atmogeomigratory paths of tritium distribution. Plant indicators indirectly reflect the impact of this migration flow on the direct absorption of tritium by organic matter from the air, or its absorption from the root layer of the soil, where the heavy isotope of hydrogen enters with atmospheric precipitation.

In nature, mosshead sculpins (Clinocottus globiceps) are challenged by fluctuations in temperature and oxygen levels in their environment. However, it is unclear how mosshead sculpins modulate the permeability of their branchial epithelia to water and O2 in response to temperature or hypoxia stress. Acute decrease in temperature from 13 to 6 oC reduced diffusive water flux rate by 22% and ṀO2 by 51%, whereas acute increase in temperature from 13 to 25 oC increased diffusive water flux rate by 217% and ṀO2 by 140%, yielding overall Q10 values of 2.08 and 2.47 respectively. Acute reductions in oxygen tension from >95% to 20% or 10% air saturation did not impact diffusive water flux rates, however, ṀO2 was reduced significantly by 36% and 65% respectively. During 1-h or 3-h recovery periods diffusive water flux rates were depressed while ṀO2 exhibited overshoots beyond the normoxic control level. Many responses differed from those seen in our parallel earlier study on the tidepool sculpin, a cottid with similar hypoxia tolerance but much smaller gill area that occupies a similar environment. Overall, our data suggest that during temperature stress, diffusive water flux rates and ṀO2 follow the traditional osmo-respiratory compromise pattern, but during hypoxia and re-oxygenation stress, diffusive water flux rates are decoupled from ṀO2. [ABSTRACT FROM AUTHOR]

After decades of research, the biological effects of tritium have been basically clear. Compared with many studies on tritium biology and RBE value, the research on the toxicity mechanism is relatively lacking. Previous research on the mechanism of tritiated water toxicity focused on oxidative stress, cell apoptosis, and DNA damage, but the specific molecular mechanism is lacking. With the development of molecular biology technology, it has become possible to elucidate the molecular mechanism of internal tritium radiation damage at multiple levels. In this paper, we reviewed our studies over the past ten years to clarify the mechanism of tritium toxicity from different aspects such as miRNA, DNA methylation, and gene expression changes. Some key target molecules were found and tried to be used to evaluate the tritium toxicity. [ABSTRACT FROM AUTHOR]

Marine flatfishes have a low metabolic rate and routinely encounter large fluctuations in salinity, and are therefore of interest in the study of diffusive water flux (a proxy for transcellular water permeability), oxygen consumption (ṀO2), ammonia excretion and urea-N excretion as a function of salinity and seawater [Ca2+]. These parameters were measured in two coastal marine flatfishes, Pacific sanddab and Rock sole acclimated to 31 ppt and exposed acutely (for up to 3 h), to environmentally relevant salinities of 45, 15.5, or 7.5 ppt. In both species, diffusive water flux and ammonia excretion rates increased as salinity decreased. ṀO2 and urea-N excretion rates remained relatively unchanged. Nitrogen quotient analysis indicated increased oxidation of protein at lower salinity. A second experimental series was performed on Rock sole to separate the effects of salinity from those of ambient [Ca2+]. In direct contrast to the significant increase seen at 7.5 ppt, reducing salinity from 31 ppt to 7.5 ppt while maintaining [Ca2+] at 10 mM or increasing it to 20 mM resulted in no change in diffusive water flux rate, demonstrating that reduced [Ca2+], rather than reduced salinity itself, is the primary cause for the increases in diffusive water flux. However, ammonia excretion rate increased when salinity was decreased and [Ca2+] was increased compared to 31 ppt with added [Ca2+]. Our results demonstrate that both diffusive water flux and ammonia excretion rates are a function of salinity, that neither are coupled to ṀO2, and that ambient [Ca2+] also plays a role in these rates. [ABSTRACT FROM AUTHOR]

[Display omitted] Comparative analysis of the alkaline phosphatase post-inactivation dynamics in natural and tritiated water (H 2 O and HTO, respectively) after ultrasonic or γ-irradiations was performed. It has been established that in HTO, unlike in H 2 O, the enzyme retains its activity up to 15 days. It is hypothesised that different hydrogen bond structure of tritiated water results in a lower effect of ultrasound or gamma-irradiation reactive species onto enzyme globules. [ABSTRACT FROM AUTHOR]

Simple Summary: Tritium is one of the most abundant radioactive elements in nuclear waste and is difficult to remove. In addition, tritiated water can enter an organism through the skin, respiratory and digestive systems. Tritiated water damages a large portion of organs or even causes cancer due to internal radiation. In our study, the changes in the cell viability of the immortal human keratinocyte HaCaT cell line after exposure to tritiated water were investigated, and the related molecular mechanisms were analyzed using sequencing technology and bioinformatics methods. Meanwhile, a Western blot assay was conducted to verify some of the sequencing results. The results provide a theoretical basis for researching the mechanisms of tritiated water hazards. Radioactive elements, such as tritium, have been released into the ocean in large quantities as a result of the reactor leakage accident. In this study, an MTT assay demonstrated that the viability of HacaT cells decreased after tritiated water treatment. Bioinformatics analysis was used to analyze gene changes in the HacaT cells. The sequencing results showed 267 significantly differentially expressed genes (DEGs), and GO enrichment analysis showed that the DEGs were mainly divided into three parts. The KEGG pathway analysis showed that the up-regulated DEGs were involved in Wnt and other pathways, while the down-regulated DEGs were involved in Jak–STAT and others. A Western blot assay was used to verify the parts of the sequencing results. This study was the first to explore the mechanism of tritiated water on HacaT cells using Transcriptome analysis. The results will provide a theoretical basis for the study of tritiated water hazard mechanisms. [ABSTRACT FROM AUTHOR]

• Real-time monitoring of deuterium in water has been shown via an industrial FTIR. • FTIR is fast, produces no secondary waste and has a large existing supplier base. • Detection limits for a benchtop and industrialised FTIR system were determined. • FTIR is a viable means of quantifying high activity tritiated water non-destructively. Tritiated water will be present in many demonstrator class fusion devices in a wide array of locations and concentrations. Accurate and fast measurement will be a key requirement to ensure suitable process monitoring, safety assurance and tritium tracking is in place. This work quantifies the deuterium detection limits achievable using a benchtop transmission Fourier transform infrared (FTIR) instrument and an industrialised attenuated total reflectance (ATR)-FTIR instrument to understand the capabilities of these techniques for real-time monitoring of aqueous tritium. Deuterium limits of detection of 4.62 × 10-5 mol mL-1 and 1.07 × 10-3 mol mL-1 were demonstrated with measurement times of 10s for the transmission FTIR and ATR-FTIR, respectively. These instruments are considered viable for the measurement of high concentration tritiated water and have many potential benefits associated with their deployment. [ABSTRACT FROM AUTHOR]

• A mathematical model is built for the prediction of operation temperature and RH of exhaust moist gas for tritiated water transportation. • The relationship between the curve of saturated moist air and the line linked atmospheric point and operation point illustrate the occurrence of condensation. • The critical temperature of the exhaust gas emit under saturation is obtained by the calculation according to the tangent line from the atmospheric point and is tangent to the fitting curve of saturated moist air. A mathematical model is built for the prediction of operation parameters for tritiated water transferred by air from nuclear reactors. Exhaust moist gas containing tritiated water vapor is emitted and diffused into the atmosphere. It should be ensuring that no condensate water formation during the mixture of exhaust moist gas and atmosphere to avoid local radiation. The occurrence of water condensation during the mixture of exhaust moist gas and atmospheric air is analyzed according to a fitting equation of saturated moist gas in a psychrometric chart. The mathematical model which predict operation temperature and RH of exhaust moist gas for certain atmospheric temperature and RH is built. The mathematical model is verified in CFD for five typical operating conditions. The effect of atmosphere temperature/RH on operation temperature and RH is analyzed. The operation strategy for tritiated water transferred by air under different atmospheric conditions is discussed and presented. [ABSTRACT FROM AUTHOR]

A photoacoustic detection of tritiated water (HTO) is presented. The method uses cantilever-enhanced photoacoustic spectroscopy (CEPAS) to reach sub-ppb sensitivity for HTO in the gas phase. A noise equivalent concentration of 0.88 ppb is reached with a sampling time of 1 min. The high performance and small sample volume of CEPAS allows sensitive detection of HTO from a sample with low total activity.

Tritium extraction from radioactively contaminated cement mortar samples was performed using heating and liquid scintillation counting methods. Tritiated water molecules (HTO) can be present in contaminated water along with water molecules (H2O). Water is one of the primary constituents of cement mortar dough. Therefore, if tritium is present in cement mortar, the buildings and structures using this cement mortar would be contaminated by tritium. The radioactivity level of the materials in the environment exposed to tritium contamination should be determined for their disposal in accordance with the criteria of low-level radioactive waste disposal facility. For our experiments, the cement mortar samples were heated at different temperature conditions using a high-temperature combustion furnace, and the extracted tritium was collected into a 0.1 M nitric acid solution, which was then mixed with a liquid scintillator to be analyzed in a liquid scintillation counter (LSC). The tritium extraction rate from the cement mortar sample was calculated to be 90.91% and 98.54% corresponding to 9 h of heating at temperatures of 200 °C and 400 °C, respectively. The tritium extraction rate was close to 100% at 400 °C, although the bulk of cement mortar sample was contaminated by tritium.

The exchange behaviors of hydrogen isotopes between protonated lithium metal compounds and deuterated water or tritiated water were investigated. The various protonated lithium metal compounds were prepared by acid treatment of lithium metal compounds with different crystal structures and metal compositions. The protonated lithium metal compounds could more effectively reduce the deuterium concentration in water compared with the corresponding pristine lithium metal compounds. The H+ in the protonated lithium metal compounds was speculated to be more readily exchangeable with hydrons in the aqueous solution compared with Li+ in the pristine lithium metal compounds, and the exchanged heavier isotopes were speculated to be more stably retained in the crystal structure compared with the light protons. When the tritiated water (157.7 kBq/kg) was reacted with the protonated lithium metal compounds, the protonated lithium manganese nickel cobalt oxide was found to adsorb and retain twice as much tritium (163.9 Bq/g) as the protonated lithium manganese oxide (69.9 Bq/g) and the protonated lithium cobalt oxide (75.1 Bq/g) in the equilibrium state.

Large volumes of water containing tritium are generated during the operation, decommissioning, and incident-management of nuclear installations and related facilities, and are expected to increase with the ongoing expansion of nuclear power generation. If released into the environment, this water could pose a substantial environmental threat to living organisms. However, conventional isotope separation techniques, such as cryogenic distillation and catalytic exchange, are inadequate for efficiently isolating significant quantities of low-level tritiated water because of the complex machinery and excessive energy required, and the potential for hydrogen-gas detonation. In contrast, water distillation (WD), as a traditional technology, has the unique advantages of simple operation, no corrosive and toxic substances, and no hydrogen explosion risk, but problems of small separation coefficient and low efficiency always exist in this technique. However, the separation effect of WD can be effectively improved by improving the process variables in the process of WD, such as temperature, distillation column diameter, and packing dimensions, so as to adapt WD to the separation of industrial tritiated water. This study provides a thorough exposition of the basic principles and distinctive features of water distillation and examines the effect of various operational parameters on separation efficiency to adapt the process for the industrial separation of tritiated water. The impact of various process variables on the separation efficiency of tritiated water via distillation was investigated, and results show that optimizing these variables can markedly improve the separation efficiency of water distillation. In particular, decreasing the dimensions of the packing material or altering its properties can lead to higher separation factors and lower residual tritiated water concentration. These findings suggest that water distillation can be used for the separation of tritiated water. By optimizing its operational parameters, water distillation can become a viable method for the industrial separation of tritiated water and is expected to play a significant role in this field in the future.

The paper considers the application of nuclear magnetic resonance for measurement of fluid-flow. The paper is of an experimental nature. Flowmeter based on nuclear magnetic resonance is extremely precise. The combined measurement uncertainty can be 0.1 %. Such a value of measurement uncertainty indicates that it is a matter of a deterministic and not of a stochastic quantity. This high degree of reliability of the method is theoretically and mathematically described. The paper presents a measurement scheme for flow measurement. Water flow measurement was performed on the principle of nuclear magnetic resonance and on the basis of tritiated water (which is considered to be the most accurate classical method). The obtained results show that the measurement of flow based on nuclear magnetic resonance is more accurate (especially at higher flow). This is explained by the higher inertial mass of HTO tritiated water molecules than the standard H2 O mass and the possible transition of tritiated water to H3HeO. In this way, it has been proven that tracing water based on nuclear magnetic resonance is the only real tracing of water by water. The obtained results show that tracing water with tritiated or heavy water is not tracing water by water which is explained by different inertial masses.

The suitability of cryogenic vacuum extraction for sampling free water (F-water) extracted from environmental materials (grass and soil) was examined with respect to low-level (~ 1 Bq L−1) and precise determination of tritium (3H) concentrations in the extracted water. Tests were conducted using addition-recovery experiments of water containing low 3H activity concentrations (0.43 ± 0.046 Bq L−1) added to dried grass or soil. The results revealed that 3H concentrations in F-water did not significantly differ before and after cryogenic vacuum extraction in both experiments. This suggests that the cryogenic vacuum extraction is useful for sampling F-water to determine 3H concentration in the water. [ABSTRACT FROM AUTHOR]

In the greenhouse experiment in time dynamics the peculiarities of tritiated water transpiration flux from an aqueous feeding solution to the white willow (Salix alba L.) tissues were studied. The experimental results are analyzed from the standpoint of chemical kinetics. From the experimental data, the rate constants of the processes of tritium removal by the biogenic flow from the aquatic food environ-ment, its entry into the intracellular sap of wood and leaves, and transformation into an organically bound form were calculated. Up to 70% of tritium absorbed by plants from the aqueous feeding solution takes part in the transpiration-assimilation cycle through the aquatic tissues of the plants; about 30% evaporates through the leaves into the atmosphere. The water of the nutrient medium rises up through the plant by the transpiration flux at high speed (1.6 ± 28% mg×s–1) rises along the xylem by the plant. Within two weeks, the concentration of tritium in the intercellular sap of different parts of the trunk is almost equalized. In the leaf during photosynthesis, the main process of fractionation of hydrogen isotopes occurs. The tritium concentration in the leaves is significantly lower (29%) than in the trunk due to transpiration into the atmosphere through the stomata and cuticle. The obtained data testify to the "threshold" mecha-nism of tritium assimilation in the organic phase of the plants and the cyclicity of the migration processes in the aqueous phase of the living matter. The organically bound tritium concentration reaches a maximum value (7% of the activity of water in the aqueous feed-ing solution) during the first week, then decreases and equalizes in all parts of the trunk. Using a radioactive marker (tritiated water) the specific velocity of the ascending xylem flux of water in the white willow seedlings is assessed to (9.5±0.3)×10–5g×s–1

The features of tritium adsorption by clay rocks, which mainly consist of clay minerals with high adsorption abilities for tritium oxide (НTO) and super heavy water (T2O), were studied after their thermal treatment at a temperature of 105 and 500 °C. The observation was carried out in a closed system "tritiated water - clay rock". Indicators of the dynamics of growth of tritium adsorption by heat-treated clay rocks over 380 days are obtained. It was found that the adsorption of tritium in this observation system actively grows for the first 30 - 40 days for all the studied minerals, and then slows down. White clays retain an increase in adsorption over the entire observation period of 380 days.

Radioactive elements, such as tritium, have been released into the ocean in large quantities as a result of the reactor leakage accident. In this study, an MTT assay demonstrated that the viability of HacaT cells decreased after tritiated water treatment. Bioinformatics analysis was used to analyze gene changes in the HacaT cells. The sequencing results showed 267 significantly differentially expressed genes (DEGs), and GO enrichment analysis showed that the DEGs were mainly divided into three parts. The KEGG pathway analysis showed that the up-regulated DEGs were involved in Wnt and other pathways, while the down-regulated DEGs were involved in Jak–STAT and others. A Western blot assay was used to verify the parts of the sequencing results. This study was the first to explore the mechanism of tritiated water on HacaT cells using Transcriptome analysis. The results will provide a theoretical basis for the study of tritiated water hazard mechanisms.

As the decommissioning of Fukushima Daiichi nuclear power plant (NPP) progresses, the issue of how to deal with tritiated water has been attracting attention, both domestically and internationally. This article summarises the live discussion at the International Symposium on Tritiated Water, which was held by the Japan Health Physics Society (JHPS) in June 2020. Two issues – the scientific safety of tritiated water and social consensus building – were covered in the live discussion. The importance of further disclosure and dissemination of information based on steady monitoring was highlighted. It was also pointed out that scientific knowledge and scientific research data are merely the bottom line to achieve social consensus. Through the discussions, it was recognised that the role of JHPS is not only to look at the technical issues of safety, but also to look at social issues from the point of view of radiation protection, and to support the solution of these issues. [ABSTRACT FROM AUTHOR]

The determination of the 'source-term' based on previous measurements of tritiated water in water samples (Part 1), as well as the possible effluent plumes from Cernavoda Nuclear Power Plant Romania led to a emission scenario as working basis for a future real-time simulation and sampling exercise within Dobrogea that will include event scenarios for radioactive atmospheric releases assessed by an expert software platform, developed at IFIN-HH. [ABSTRACT FROM AUTHOR]

• Selective adsorption characteristics of layered titanate for hydrogen isotope water. • Selective adsorption is from the difference in penetration rate between H2O and HTO. • The penetration rate in the interlayer was responsible for the adsorption mechanism. • The technology could lead to the development of tritium water separation technology. Inorganic materials, such as concrete used in many fusion reactor facilities, adsorb tritiated water, which makes decontamination difficult and causes the generation of a large amount of nonflammable radioactive waste. Water strongly adsorbed by surface with inorganic materials causes tritiated water to be adsorbed more strongly than light water as an isotope effect, resulting in the accumulation of tritium within inorganic materials. In response to this well-known phenomenon, we found that the composition-controlled titanate, an inorganic material, can selectively inhibit the adsorption of tritiated water onto the material, a characteristic that is the exact opposite of common knowledge. Focusing on "layered titanate," a general-purpose inorganic material that can be given various characteristics by controlling its shape and composition, we examined adsorption properties of tritiated water on the material experimentally by the method of indirectly contacting inorganic materials with tritiated water as vapor in an airtight container. Molecular sieve as an inorganic material that selectively adsorbs tritium concentrates tritiated water within itself, resulting in a lower concentration of tritiated water in the container. In contrast, it was found that titanate with composition control showed the exact opposite tendency of tritiated water concentration. This result is considered as a selective inhibition of tritiated water adsorption on the material. It was shown that it is possible to control the composition of titanate to selectively inhibit the adsorption of tritiated water onto materials based on a new concept. [ABSTRACT FROM AUTHOR]

The diffusion of tritiated water (HTO) vapor from the spent fuel storage bay to the spent fuel storage building (SFSB) may lead to internal exposure to occupational workers. In order to reduce this internal exposure, air curtains are provided over the spent fuel storage bay to effectively remove HTO diffusing from spent fuel storage bay to SFSB. The radiation doses to the occupational workers are controlled well below the permissible level by monitoring the air concentration of HTO in the SFSB area. In the present study, it is brought out that few additional monitoring of air concentration of HTO above the spent fuel storage bay can give useful information about the effectiveness of air curtains in the removal of HTO and the estimation of environmental releases of HTO. A three-dimensional advection-diffusion-based model is developed to demonstrate the effectiveness of air curtains in the removal of HTO and for the estimation of environmental releases of HTO, utilizing these additional measurements. The study showed that air curtains are an effective mechanism to reduce the air concentration of HTO in SFSB and remove almost 50% of HTO activity using only around 24% of the ventilation air supplied to the SFSB. The environmental release rate of HTO estimated in this study was in good agreement with the measured release rate. The methodology developed here can also be utilized to carry out parametric studies to see the impact of changes in the parameters related with air curtains in the removal of HTO, thus for better designing of air curtains.

The waters of two lakes and two streams that dominate in the Šar Mountains aquatorium were analyzed. The tritium profile of soil was also recorded. All samples were taken at approximately the same time, together with samples of precipitation. During the period of taking samples, the ambient temperature conditions were taken into account for ten days around the time of sampling. Monitoring of the seasonal maximum with taking into account the obtained tritium soil profile and the temperature on and around the day of sampling unambiguously showed that all tested water in the Šar Mountains aquatorium is of atmospheric origin and as such unsuitable for any major transformation for commercial purposes. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 171007]

Possible scenarios, correlation factors and propagation intervals of direct releases in liquid effluents and through indirect contributions by gaseous effluents from Cernavoda Nuclear Power Plant Romania to the tritium inventory in water samples from the central-northern area of Dobrogea are proposed. Part 1 focuses on experimental data. [ABSTRACT FROM AUTHOR]

We aimed to determine the toxic effects of tritiated water (HTO) on 12 generations (T1-T12) of human umbilical vein vascular endothelial cells (HUVECs) and elucidate the underlying mechanisms. We evaluated cellular senescence, interleukin (IL) 8 concentrations, and angiogenesis using β-galactosidase staining, enzyme-linked immunosorbent assay, and in vitro assays, respectively. The adhesion properties of contaminated cells and differentially expressed genes were assessed using the xCELLigence RTCA SP system and gene chip analysis, respectively. We found that long-term exposure to low levels of HTO can reduce the adhesion of HUVECs to the cellular matrix as well as their angiogenic capacity, while increasing their permeability, senescence, and adhesion to monocytes. Interleukin 8 activated the p38 and Epidermal Growth Factor Receptor (EGFR) pathways in HTOtreated cells and hence was identified as a key candidate of biomarker. The present study clarified the toxicity of HTO in vascular endothelial cells and identified IL8 as a novel protective target with important theoretical and practical values. [ABSTRACT FROM AUTHOR]

The features of tritium adsorption by clay rocks, which mainly consist of clay minerals with high adsorption abilities for tritium oxide (НTO) and super heavy water (T2O), were studied after their thermal treatment at a temperature of 105 and 500 °C. The observation was carried out in a closed system “tritiated water - clay rock”. Indicators of the dynamics of growth of tritium adsorption by heat-treated clay rocks over 380 days are obtained. It was found that the adsorption of tritium in this observation system actively grows for the first 30 - 40 days for all the studied minerals, and then slows down. White clays retain an increase in adsorption over the entire observation period of 380 days. [ABSTRACT FROM AUTHOR]

Our understanding is limited on how fish adjust the effective permeability of their branchial epithelium to ions and water while altering O2 uptake rate (MO2) with acute and chronic changes in temperature. We investigated the effects of acclimation temperature (8 °C, 13 °C and 18 °C) and acute temperature challenges [acute rise (acclimated at 8 °C, measured at 13 °C and 18 °C), acute drop (acclimated at 18 °C, measured at 8 °C and 13 °C) and intermediate (acclimated at 13 °C, measured at 8 °C and 18 °C)] on routine MO2, diffusive water flux, and net sodium loss rates in 24-h fasted rainbow trout (Oncorhynchus mykiss). In the temperature challenge tests, measurements were made during the first hour. In acclimated trout at all temperatures, allometric mass scaling coefficients were much higher for diffusive water flux than for MO2. Furthermore, the diffusive water flux rate was more responsive (overall Q10 = 2.75) compared to MO2 (Q10 = 1.80) over the 8–18 °C range, and for both, Q10 values were greater at 8–13 °C than at 13–18 °C. The net Na+ flux rates were highly sensitive to acclimation temperature with an overall Q10 of 3.01 for 8–18 °C. In contrast, very different patterns occurred in trout subjected to acute temperature challenges. The net Na+ flux rate was temperature-insensitive with a Q10 around 1.0. Both MO2 and diffusive water flux rates exhibited lower Q10 values than for the acclimated rates in response to either acute increases or decreases in temperature. These results fit Pattern 5 of Precht (undercompensation, reverse effect) and more precisely Pattern IIB of Prosser (reverse translation). These inverse compensatory patterns suggest that trout do not alter their rates very much when undergoing acute thermal challenges (diurnal fluctuations, migration through the thermocline). The greater changes seen with acclimation may be adaptive to long-term seasonal changes in temperature. We discuss the roles of aquaporins, spontaneous activity, and recent feeding in these responses. [ABSTRACT FROM AUTHOR]

Tritium, a radioactive isotope of hydrogen of natural and anthropogenic origin, is ubiquitously present in the environment. Effluents of nuclear centers of production are significant anthropogenic sources. With the upcoming project of thermonuclear fusion, tritium releases in the environment may increase. It is therefore important to characterize the ecological risk linked to tritium. The effects of tritiated water (HTO) were therefore studied in zebrafish larvae exposed for 10 d to different dose rates, 1.1 × 102, 4.1 × 102, and 3.8 × 103 µGy/h for larvae corresponding, respectively, to a water contamination of 104, 105, and 106 Bq/mL of HTO. Those dose rates were higher than 10 μGy/h, which is the threshold recommended to start monitoring ecosystems where radiological contaminants are present. Mortality, embryo‐larval development, immune toxicity, genotoxicity, neurotoxicity, and alterations of tissues were investigated. The results showed that HTO exposure induced DNA damage and reactive oxygen species production and modulated the expression of genes involved in detoxification processes. Moreover, modifications of the muscular tissues (degradation of myofibrils at 4 d post fertilization and disorganization of mitochondria at later stages) were observed. The results differed with HTO dose rates and with developmental stages. These results will drive future research for the development of new HTO‐sensitive biomarkers and will allow us to progress in the characterization of the modes of action of tritium in fish. Environ Toxicol Chem 2020;39:648–658. © 2019 SETAC [ABSTRACT FROM AUTHOR]

• No impurities or vacancies of the monolayer graphene were observed after immersing in tritiated water for six months. • The TEM diagram showed the complete structure of monolayer graphene. • The copper foil substrate was oxidized during the immersing process. • XPS results showed that the graphene monolayer was not doped with oxygen atoms after immersion. Graphene has been successfully applied for the "protium (P)-deuterium (D)" separation, while theoretical studies have shown higher feasibility for "protium (P)-tritium (T)" separation. However, graphene for "P-T" separation is facing the challenge of radiation damage due to the beta (β) rays in the tritiated water and its radiolysis byproducts, which will reduce the separation efficiency and the lifetime of the graphene separation membrane. In this study, the radiation resistance ability of graphene in the tritiated water was studied by immersing the monolayer graphene samples in different solutions (protium water, deuterium water, and tritiated water with the specific activities of 5.32 × 105 Bq/L∼5.32 × 109 Bq/L). Raman spectroscopy, transmission electron microscope, and the X-ray energy spectrum (EDS) were used for the characterization. The six-month immersion in tritiated water did not damage the structure of monolayer graphene samples on copper foil substrate at the detectable level under the present analysis conditions. From the perspective of resisting radiation damage, this study preliminarily shows that using monolayer graphene for "P-T" separation in tritiated water has specific practical feasibility. [ABSTRACT FROM AUTHOR]

Tritium is one of the factors of internal exposure of the humans both in occupational and public environments. It enters the body mainly as tritiated water through inhalation, with food, drinks and through the skin; part of tritium gradually transforms into the metabolised organically bound tritium as a result of biochemical reactions. The purpose of this study was to evaluate organically bound tritium contribution to the effective dose of an adult using the biokinetic model and real dosimetric data. The data of long term monitoring from 6 studies with 17 workers or volunteers following single intake of tritiated water in the body were selected from 9 publications (1968-1997). Three two-compartment models of tritium biokinetics were used in this study: recurrent model with gradual transformation of tritium from tritiated water into organically bound tritium and tritiated water excretion; model with instant transformation of tritium into organically bound tritium and tritiated water excretion; model with instant transformation of tritium into organically bound tritium and both tritiated water and organically bound tritium excretion (according to ICRP). The ICRP model doesn’t properly reflect the real tritiated water metabolism in the human body: second exponent of the tritiated water content in the body water and accumulation of the organically bound tritium fraction are absent. The organically bound tritium fraction composes 3% of tritiated water in ICRP model. It is significantly higher compared to two other models (0,4% and 0,8%). According to the first model the contribution of OBT fraction to the mean dose varied from 1,8 to 4,6% for individuals; mean value was 3,0 ± 0,9%. According to the second model the contribution of organically bound tritium fraction was slightly higher: 3,6 ± 1,1%, according to the ICRP model – 9%. The dynamic of excretion of tritium with urine can be described with double-exponential curves and provides the basis for two-compartment modeling. The recurrent model with tritiated water excretion was more adjusted to human physiology. Contribution of organically bound tritium to effective dose can be somewhat higher than that to absorbed dose defined in this work. The presented dose assessment system can be used when specified individual absorbed dose reconstruction in tissues is necessary following accidental intake of large tritium activities.

The diffusion of tritiated water (HTO) vapor from the spent fuel storage bay to the spent fuel storage building (SFSB) may lead to internal exposure to occupational workers. In order to reduce this internal exposure, air curtains are provided over the spent fuel storage bay to effectively remove HTO diffusing from spent fuel storage bay to SFSB. The radiation doses to the occupational workers are controlled well below the permissible level by monitoring the air concentration of HTO in the SFSB area. In the present study, it is brought out that few additional monitoring of air concentration of HTO above the spent fuel storage bay can give useful information about the effectiveness of air curtains in the removal of HTO and the estimation of environmental releases of HTO. A three-dimensional advection-diffusion-based model is developed to demonstrate the effectiveness of air curtains in the removal of HTO and for the estimation of environmental releases of HTO, utilizing these additional measurements. The study showed that air curtains are an effective mechanism to reduce the air concentration of HTO in SFSB and remove almost 50% of HTO activity using only around 24% of the ventilation air supplied to the SFSB. The environmental release rate of HTO estimated in this study was in good agreement with the measured release rate. The methodology developed here can also be utilized to carry out parametric studies to see the impact of changes in the parameters related with air curtains in the removal of HTO, thus for better designing of air curtains. [ABSTRACT FROM AUTHOR]

Tritium (³H) readily combines with oxygen to form water, so its behavior in aqueous systems is controlled by hydro logic processes and it migrates at essentially the same velocity as surface and ground water. In this study removal of tritium from radioactive aqueous solution by using a strongly acidic resin (KU-2) and weakly basic resin (AN-31) by batch and column technique was investigated. Batch studies were performed to estimate the effect of pH, contact time and resin weight in the removal process as well as desorption process. The optimum pH was found to be 7.8. The maximum uptake was reached within one hour and the equilibrium was reached within 1.5 h. Desorption of radioactive tritium was achieved using 3 M HNO3 and 2 M NaOH. The removal of tritium from liquid radioactive waste using the sequential cationic and anionic columns exchangers that are being used in Egyptian liquid radioactive waste treatment plant was applied. The obtained purified water reaches the permissible level to save our environment. Finally, results indicate that KU-2 resin is an efficient ion exchanger for the removal of ³H from aqueous solution. [ABSTRACT FROM AUTHOR]

There is no doubt that estimating the exposure risk of external and internal low-dose radiation is an imperative issue in radiobiological study. Human mesenchymal stem cells (hMSCs) are multipotent and self-renewing, supporting the regeneration of damaged tissue, including tissue damaged by radiation. However, the responses of hMSCs to internal exposure to radionuclides are still insufficiently understood. In order to evaluate the adverse effects produced by internal exposure to tritiated water (HTO) at a low dose, hMSCs were exposed to 2 × 107 Bq/ml HTO, and the biological effects after the exposure were examined. Apoptosis and DNA double-strand breaks (DSBs) were assayed to analyze the cellular response to the damage induced by HTO. Slight enhancement of apoptosis was found after treatment, except at the dose of 9 mGy. The number of DSBs at 24 h post-irradiation showed that the DNA damage was able to be efficiently repaired by the hMSCs. Moreover, the increasing proportion of the cell population in S phase proved that the persistence of residual γH2AX foci at lower concentrations of HTO was attributable to the secondary production of DSBs in DNA replication. Our work adds to the available data, helping us understand the risk of stem cell transformation due to internal exposure and its correlation with low-dose radiation–induced carcinogenesis. [ABSTRACT FROM AUTHOR]

The Pacific hagfish (Eptatretus stoutii) is a representative of the most basal extant craniates, and is a marine osmoconformer with an extremely low metabolic rate (MO2 = 475 µmol O2/kg/h at 12 °C). We investigated potential physiological trade-offs associated with compensatory changes in gill ventilation and perfusion when 12 °C-acclimated hagfish were acutely exposed to 7 °C or 17 °C, as reflected in diffusive unidirectional water flux (JH2O, measured with tritiated water: 3H2O), net ammonia flux (Jamm), and plasma ion and acid-base status. JH2O was high (~ 1.4 L/kg/h at 12 °C) in comparison to marine teleosts and elasmobranchs. MO2 increased linearly with temperature (R2 = 0.991), and was more sensitive (Q10 = 3.22) in the 12-7 °C range than either Jamm (1.86) or JH2O (1.35), but the pattern reversed from 12 to 17 °C (Q10s: MO2 = 2.77, Jamm = 2.88, JH2O = 4.01). Heart rate, ventilatory index (a proxy for total ventilation), and coughing frequency also increased but with different patterns. At 17 °C, plasma [Ca2+] and [Mg2+] decreased, although osmolality increased, associated with elevations in plasma [Na+] and [Cl−]. Blood pH and PCO2 were unaffected by acute temperature changes while [HCO3−] increased. Hyperoxia (PO2 > 300 Torr) attenuated the increase in JH2O at 17 °C, did not affect Jamm, and had diverse effects on plasma ion and acid-base status. Our results suggest a clear osmorespiratory compromise occurring for the diffusive water fluxes as a result of acute temperature changes in this osmoconformer. [ABSTRACT FROM AUTHOR]

Abstract This work presents the capability of digital autoradiography, a non-destructive technique, to improve diffusion parameters determination by mean of high resolution radionuclide mapping. The results show a good agreement between Cl-36 diffusion profiles acquired by digital autoradiography compared to the classic protocol based onto multi-step-abrasive-surface-peeling procedure. The digital autoradiography technique has been successfully used to localize and quantify Cl-36-labelled radiotracer on the surface of a concrete sample and into the contaminated depth. This study shows how optimized in-diffusion investigations can be performed in only 100 days to assess the diffusion parameters of Cl-36 in a low diffusive concrete sample, prepared from a composite cement (CEM V/A), while a through-diffusion experiment would take several years to reach diffusion steady state for tritiated water, considered as the reference tracer, and consequently, to allow the estimation of the diffusion parameters for Cl-36. Highlights Cl-36 localization and quantification in concrete by digital autoradiography. Cl-36 diffusion parameters determination using optimized in-diffusion investigations. Highlighting the complementarity between two diffusion profile determination methods. [ABSTRACT FROM AUTHOR]