The radionuclide transfer between compartments is commonly described by transfer parameters representing the ratio of concentrations of an element in two compartments for equilibrium conditions. This ...is a comprehensive study on the soil-to-grass transfer factor (F
) and grass-to-cow milk transfer coefficient (F
) for stable strontium (Sr) for soil-grass (pasture)-cow (Bos taurus) milk environmental pathway under field conditions for a high rainfall tropical monsoonal climatic region of the Indian subcontinent. The study was conducted in the vicinity of the Kaiga nuclear power plant (NPP), situated ~ 58 km inland of the West Coast of the Indian subcontinent. A grass field was developed exclusively for this study, and two cows of the native breed were raised to graze on it. The soil, grass, and milk were analyzed to evaluate the F
and the F
values for the stable Sr. For comparison, several pasture lands and the cows raised by the villagers and a dairy farm were also studied. The F
values were in the range 0.18-8.6, the geometric mean (GM) being 1.8. The correlations of F
values with a range of physicochemical parameters are presented. The GM values for F
were 2.2 × 10
d L
and 7.2 × 10
d L
for the two cows raised for this study, 2.6 × 10
d L
for those raised by the villagers, and 4.2 × 10
d L
for the dairy farm. The site-specific F
value for the region was determined as 3.2 × 10
d L
. The concentration ratio (CR), defined as the ratio of Sr concentration in milk to that in feed under equilibrium conditions, exhibited less variability (1.8 × 10
-5.4 × 10
) among the three categories of cows.
This article aims to study the modification in the structural, optical and electrical properties of indium oxide thin film after gamma irradiation and estimation of sensitivity for gamma sensing ...applications. The thin film of indium oxide was deposited on a 450 °C preheated glass substrate using the spray pyrolysis technique. The deposited thin film of molar concentration 0.15 M and thickness of around 600 nm was irradiated with different gamma doses (100 Gy, 200 Gy, 300 Gy and 400 Gy). The optical properties of the irradiated film are studied using UV–Visible spectroscopy. Transmittance increased after irradiation up to 200 Gy and beyond that, it decreased. Indium oxide is an
n
-type semiconductor which exhibits both direct and indirect transitions. Both direct and indirect bandgap energy are calculated using Tauc’s plot. Extinction coefficient and refractive index variation with irradiation were also estimated. Photoluminescence study confirmed the gamma-induced defect formation and annihilation for an irradiation dose of 400 Gy and 200 Gy, respectively. Resistivity also decreased up to 200 Gy and beyond that, it increased. The sensitivity of the deposited film was estimated from the electrical measurements, and it lies between 10.7 and 53.4 mA/cm
2
/Gy.
Graphical abstract
Measurement of radiation dose has the utmost importance in the field of medicine and research. This work aims the estimation of the sensitivity of Indium oxide thin film for dosimetry application. ...Indium oxide thin film prepared using spray pyrolysis on a glass substrate with an optimized concentration of 0.1 M and temperature of 450 0C was exposed to different gamma radiation doses using Co- 60 as the radiation source. The impact of irradiation on the structural properties of the film was investigated by XRD and a higher crystallite size was obtained for a dose of 200 Gy. The phase purity and vibrational modes of the irradiated films were investigated using Raman spectra. The optical characterization of the irradiated film shows negligible variation in bandgap with irradiation. The optical parameters like refractive index and extinction coefficient are also extracted from optical data. The reduction in the intensity of PL peaks after irradiation was attributed to the annihilation of gamma-induced defect levels. The thermoluminescence curve indicates the suitability of In2O3 as dosimeters. XPS analysis also supports the annihilation of defects at 200 Gy. The electrical measurement was used to find the sensitivity of the film at different applied voltages and it lies in the range of 101 − 380 mA/cm2/Gy. The fact that irradiated material undergoes a change in physical properties due to the influence of gamma-ray can be utilized for gamma dosimetry applications. The changes induced by gamma-ray in structural, optical and electrical properties have been investigated in detail.
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•Sensitivity estimation of INO up to a gamma dose of 200 Gy was carried out for gamma dosimetry applications.•The variation in the intensity of the Raman peak can be ascribed to dampened vibrational modes of INO.•XPS analysis supports the annihilation of defects occurring at 200 Gy.•The thermoluminescence curve indicate the suitability of indium oxide for dosimeters.•The estimated sensitivity lies in the 101-308 mA/cm2/Gy range.
India is the second largest producer of rice (Oryza sativa L.) in the world and rice is an essential component of the diet for a majority of the population in India. However, detailed studies aimed ...at the evaluation of radionuclide transfer factors (F(v)) for the rice grown in India are almost non-existent. This paper presents the soil to rice transfer factors for natural ((226)Ra, (228)Ra, (40)K, and (210)Pb) and artificial ((137)Cs) radionuclides for rice grown in natural field conditions on the West Coast of India. A rice field was developed very close to the Kaiga nuclear power plant and the water required for this field was drawn from the cooling water discharge canal of the power plant. For a comparative study of the radionuclide transfer factors, rice samples were also collected from the rice fields of nearby villages. The study showed that the (226)Ra and (228)Ra activity concentrations were below detection levels in different organs of the rice plant. The soil to un-hulled rice grain (40)K transfer factor varied in the range of 6.5 × 10(-1) to 2.9 with a mean of 0.15 × 10(1), and of (210)Pb varied in the range of <1.2 × 10(-2) to 8.1 × 10(-1) with a mean of 1.4 × 10(-1), and of (137)Cs varied in the range of 6.6 × 10(-2) to 3.4 × 10(-1) with a mean of 2.1 × 10(-1). The mean values of un-hulled grain to white rice processing retention factors (F(r)) were 0.12 for (40)K, 0.03 for (210)Pb, and 0.14 for (137)Cs. Using these processing retention factors, the soil to white rice transfer factors were estimated and these were found to have mean values of 1.8 × 10(-1), 4.2 × 10(-3), and 3.0 × 10(-2) for (40)K, (210)Pb, and (137)Cs, respectively. The study has shown that the transfer of (40)K was higher for above the ground organs than for the root, but (210)Pb and (137)Cs were retained in the root and their transfer to above the ground organs of the rice plant is significantly lower.
As a part of establishing a regional database on natural radioactivity, the atmospheric concentrations of 210Pb and 7Be were measured over a three and half year period (2014–2017) in Mangalore and ...Kaiga in the South West Coast of India. A total of 99 air samples, collected in the different months of the year, were analysed in this study. The mean activity concentrations of 7Be and 210Pb were found to be 5.5 ± 3.1 mBq m−3 and 1.1 ± 0.73 mBq m−3, respectively. Both the radionuclides exhibited strong seasonal variations, with maximum concentration of 7Be occurring in the summer and that of 210Pb in the winter season. The concentration of both the radionuclides was minimum in the rainy season. Higher 210Pb concentration during winter was attributed to the ingression of continental air masses due to the wind regime from the North East. The sunspot number index of the solar activity also plays an important role in the increase and decrease of 7Be concentration in the air. A clear trend of increased and lowered concentration of 7Be with lower and higher solar activity (low and high sunspot number), respectively, in accordance with the 11-year solar cycle, was observed in this study. The temporal variation of PM10 concentration was also studied and it showed maximum value in the winter and minimum in the rainy season with an average of 56.9 μg m−3. Statistically significant positive correlation was observed between the PM10 and 210Pb activity concentration, whereas a weak correlation was observed between PM10 and 7Be. This is due to the fact that 7Be is largely associated with sub-micrometer size particles, whereas PM10 is contributed by larger sizes. The dependence of the activity concentrations of 7Be and 210Pb with meteorological parameters such as rainfall, temperature, and humidity was studied through linear regression analysis. A significant correlation was observed between 7Be and 210Pb concentrations with rainfall intensity (with identical correlation coefficients), which suggested that the removal mechanisms of these two radionuclides were similar. 7Be showed a strong correlation with temperature, whereas 210Pb with humidity. A comparison of the data obtained in the present study for the South West Coast of India with the global literature values of 7Be and 210Pb in aerosols showed that the values did not reflect the well-known latitudinal dependence of the 7Be tropospheric fluxes. Overall, the study provides an improved understanding of the correlation and variability of 210Pb and 7Be concentrations in the atmosphere in the South West Coast of India.
•Regional database on activity of atmospheric 7Be and 210Pb in Southwest Coast of India was established.•Rainfall is the major removal pathway for the 7Be and 210Pb from the atmosphere.•Dependence of solar activity with cosmogenic 7Be was studied.•A clear dependence of 7Be activity on solar activities was observed.•Causal factors for the temporal variability of 7Be and 210Pb concentrations were identified.
The activity concentration of (226)Ra, (232)Th and (40)K was measured for soil samples collected from 34 locations of Tumkur District, Karnataka, India, using HPGe detector. The activity ...concentration of (226)Ra, (232)Th and (40)K varied from 9.6 to 71.6, 12.3 to 333.3 and 194.3 to 1527.7 Bq kg(-1) with an average value of 33.15, 123.01 and 877.76 Bq kg(-1), respectively. The absorbed and annual effective outdoor doses were found to be highest at Ponnasamudra with 258.98 nGy h(-1) and 317.62 μSv and lowest at Sira with 36.42 nGy h(-1) and 44.67 μSv, respectively. The external hazard index ranged from 0.21 to 1.58 with an average of 0.75. It was significant in 11 locations as it exceeded unity.
Radon (222Rn), thoron (220Rn), and their decay products contribute a major fraction (more than 50%) of doses received from ionisation radiation in public domain indoor environments and occupation ...environments such as uranium mines, thorium plants, and underground facilities, and are recognised as important radiological hazardous materials, which need to be controlled. This paper presents studies on the removal of 222Rn and 220Rn from air using coconut shell-based granular activated charcoal cylindrical adsorber beds. Experiments were conducted to evaluate the 222Rn and 220Rn adsorption characteristics, and the mitigation efficiency of coconut-based activated charcoal available in India. The performance parameters evaluated include breakthrough time (τ) and adsorption coefficient (K), and degassing characteristics of the charcoal bed of varying dimensions at different flow rates. While the breakthrough for 222Rn occurred depending on the dimension of the adsorber bed and flow rates, for 220Rn, the breakthrough did not occur. The breakthrough curve exhibited a stretched S-shape response, instead of the theoretically predicted sharp step function. The experiments confirm that the breakthrough time individually satisfies the quadratic relationship with respect to the diameter of the bed, and the linear relationship with respect to the length, as predicted in the theory. The K value varied in the range of 2.3–4.12 m3 kg−1 with a mean value of 2.99 m3 kg−1. The K value was found to increase with the increase in flow rate. Heating the charcoal to ∼100 °C resulted in degassing of the adsorbed 222Rn, and the K of the degassed charcoal and virgin charcoal were found to be similar with no deterioration in performance indicating the re-usability of the charcoal.
•222Rn and 220Rn removal from air using activated charcoal bed is demonstrated.•Breakthrough time and adsorption coefficient were evaluated.•A sustained mitigation factor exceeding 105 was demonstrated for 220Rn.•Degassing characteristics excellently demonstrate the reusability of charcoal.•Results would find application in designing 220Rn mitigation systems for workplaces.
•Gamma dose rate was measured around a region indentified as prospective uranium mining area.•Dose was evaluated by GM based survey meter, TLDs, and analyses of soil samples for radionuclides.•Dose ...evaluated from radionuclide activities is an underestimation when compared to in situ measurement.•In situ measurement of dose by survey meter accounts for non-uniform distribution of radionuclides.
Indoor and outdoor gamma dose rates were evaluated around a prospective uranium mining region – Gogi, South India through (i) direct measurements using a GM based gamma dose survey meter, (ii) integrated measurement days using CaSO4:Dy based thermo luminescent dosimeters (TLDs), and (iii) analyses of 273 soil samples for 226Ra, 232Th, and 40K activity concentration using HPGe gamma spectrometry. The geometric mean values of indoor and outdoor gamma dose rates were 104nGyh−1 and 97nGyh−1, respectively with an indoor to outdoor dose ratio of 1.09. The gamma dose rates and activity concentrations of 226Ra, 232Th, and 40K varied significantly within a small area due to the highly localized mineralization of the elements. Correlation study showed that the dose estimated from the soil radioactivity is better correlated with that measured directly using the portable survey meter, when compared to that obtained from TLDs. This study showed that in a region having localized mineralization in situ measurements using dose survey meter provide better representative values of gamma dose rates.
Air-to-grass mass interception factors for radionuclide are important basic input parameter for the estimation of radiation dose to the public around a nuclear power plant. In this paper, we present ...the determination of air-to- grass mass interception factors for iodine using a 2 m × 2 m × 2 m (l × b × h) size environmental chamber. The temperature, humidity, and rainfall inside the environmental chamber was controlled to required values to simulate different environmental conditions. Grass (Pennisetum purpureum, Schum), grown in pots, was kept inside the environmental chamber and stable iodine in elemental form was sublimed quickly inside the chamber to simulate an accidental release of iodine to the environment. The concentration of iodine in the air was measured periodically by drawing air through a bubbling setup, containing 1% sodium carbonate solution. The mass interception factor for dry deposition varied in the range of 0.25–7.7 m2 kg−1 with mean value of 2.2 m2 kg−1 with respect to fresh weight of grass, and that due to wet deposition varied in the range of 0.6–4.8 m2 kg−1 with mean value of 2.3 m2 kg−1. The mass interception factor was inversely correlated with the total iodine deposited through dry deposition as well as with the rainfall.
•Mass interception factor of iodine for grass was estimated by chamber experiments.•Mean value of mass interception factor for dry depositions was 2.2 m2 kg−1.•Mean value of mass interception factor for wet deposition was 2.3 m2 kg−1.•Mass interception factor was inversely correlated with the total iodine deposited.•Mass interception factor was inversely correlated with total rainfall.
Detailed studies were carried out to establish site-specific soil to grass transfer factors (Fv) and grass to cow milk transfer coefficients (Fm) for radioactive cesium (137Cs) and stable cesium (Cs) ...for Kaiga region, where a nuclear power station has been in operation for more than 10 years. The study included adopted cows, cows of local farmers, and cows from the dairy farm. A grass field was developed specifically for the study and 2 local breed cows were adopted and allowed to graze in this grass field. The soil and grass samples were collected regularly from this field and analyzed for the concentrations of 137Cs and stable Cs to evaluate the soil to grass Fv values. The milk samples from the adopted cows were analyzed for the 137Cs and stable Cs concentrations to evaluate Fm values. For comparison, studies were also carried out in dominant grazing areas in different villages around the nuclear power plant and the cows of local farmers which graze in these areas were identified and milk samples were collected and analyzed regularly. The geometric mean values of Fv were found to be 1.1 × 10−1 and 1.8 × 10−1 for 137Cs and stable Cs, respectively. The Fm of 137Cs had geometric mean values of 1.9 × 10−2 d L−1 and 4.6 × 10−2 d L−1, respectively, for adopted Cows 1 and 2; 1.7 × 10−2 d L−1 for the cows of local farmers, and 4.0 × 10−3 d L−1 for the dairy farm cows. The geometric mean values of Fm for stable Cs were similar to those of 137Cs. The Fm value for the dairy farm cows was an order of magnitude lower than those for local breed cows. The Fm values observed for the local breed cows were also an order of magnitude higher when compared to the many values reported in the literature and in the IAEA publication. Possible reasons for this higher Fm values were identified. The correlation between Fv and Fm values for 137Cs and stable Cs and their dependence on the potassium content (40K and stable K) in the soil and grass were also studied. In order to estimate the ingestion dose accurate data of the dietary habits of the population was necessary and this data was collected through a well planned demographic survey. The internal doses to a child due to the ingestion of 137Cs along with the milk of the local cows and from the dairy farm were found to be 0.29 μSv y−1 and 0.04 μSv y−1,while that to an adult were 0.39 μSv y−1 and 0.05 μSv y−1, respectively.
•This is a detailed study on Fv and Fm for 137Cs and stable Cs around the Kaiga nuclear power plant, India.•The geometric mean values of Fv were found to be 1.1 × 10−1 and 1.8 × 10−1 for 137Cs and stable Cs, respectively.•The Fm value for 137Cs for the local breed cows was estimated to be 2.4 × 10−2 d L−1.•The Fm value for dairy farm cows (4.0 × 10−3 d L−1) was an order of magnitude lower than those for local breed cows.•The reasons for the higher Fm values for 137Cs for the local breed cows are identified.
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