Prabhjot Singh

A study of indoor radon, thoron and their progeny measurement in Tosham region Haryana, India

Abstract In the present study indoor radon, thoron and their decay products concentrations have been measured using the newly developed LR-115 type-ІІ based Radon-Thoron discriminating twin-cup dosimeters with single entry face, direct radon and thoron progeny sensors (DRPS/DTPS) respectively. The annual annihilation dose has been assessed from measured radionuclide concentration to find out major contributor of lung cancer in the study area. The measurements have been carried out in NINETY dwellings of THIRTEEN different villages situated in and around the Tosham region. This region is known to be composed of acidic volcanic and associated granites. Dwellings were selected mainly targeting different type building material used in construction of houses like concrete–brick, mud-brick, and mud-thatches along with an idea of different ventilation conditions which affects the equilibrium factor (EF). The EF in this region has been varying from 0.20 to 0.72 and 0.03–0.13 for indoor radon and thoron respectively. The average inhalation dose observed in dwellings of different villages varies from 1.33 ± 0.31–3.36 ± 0.72 mSv/y that lies within the safe limits recommended by ICRP (2011).

Cytogenetic Damage in Mobile Phone Users: Preliminary Data

Abstract Mobile telephones, sometimes called cellular (cell) phones or handies, are now an integral part of modern life. The mobile phone handsets are low-powered radiofrequency transmitters, emitting maximum powers in the range of 0.2 to 0.6 watts. Scientific concerns have increased sufficiently over the possible hazard to health from using cell phones. The reported adverse health effects include physiological, behavioural and cognitive changes as well as tumour formation and genetic damage. However findings are controversial and no consensus exists. Genotoxicity has been observed either in lower organisms or in vitro studies. The aim of the present study hence was to detect any cytogenetic damage in mobile phone users by analysing short term peripheral lymphocytes cultures for chromosomal aberrations and the buccal mucosal cells for micronuclei (aneugenicity and clastogenicity). The results revealed increased number of micronucleated buccal cells and cytological abnormalities in cultured lymphocytes indicating the genotoxic response from mobile phone use.

A follow-up study on indoor 222Rn, 220Rn their decay product concentrations in a mineralised zone of Himachal Pradesh, India

A follow-up study was taken up in a mineralised zone situated in Hamirpur district, Himachal Pradesh, India, to investigate high values of radon concentrations reported in past studies as well to update the old radon data based on bare SSNTD technique. In the present investigation, the concentrations of indoor radon, thoron and their decay products have been measured using the newly developed radon/thoron discriminating diffusion chamber with single entry face, direct radon and thoron progeny sensors (DRPS/DTPS), respectively. The measurements have been carried out in 75 dwellings of 14 different villages where the previous studies were carried out using bare SSNTD technique. It was observed that high values of earlier reported radon concentrations were mainly due to thoron interference in the Solid State Nuclear Track Detector (LR-115 type II) exposed in bare mode. Now, the average concentration values and the estimated annual inhalation dose in these villages have been found to be within the reference level as recommended by the ICRP. The annual average indoor radon and thoron concentrations observed in these dwellings have been found to vary from 44±12 to 157±73 Bq m(-3) and 44±11 to 240±125 Bq m(-3), respectively. The equilibrium equivalent concentrations of radon and thoron decay products have been observed to be in the range of 10 to 63 and 1 to 5 Bq m(-3), respectively.

Theoretical modeling of indoor radon concentration and its validation through measurements in South-East Haryana, India.

A three dimensional semi-empirical model deduced from the existing 1-D model has been used to predict indoor radon concentration with theoretical calculations. Since the major contributor of radon concentration in indoors originates from building materials used in construction of walls and floor which are mostly derived from soil. In this study different building materials have been analyzed for radon exhalation, diffusion length along with physical dimensions of observation area to calculate indoor radon concentration. Also calculated values have been validated by comparing with experimental measurements. The study has been carried out in the mud, brick and cement houses constructed from materials available locally in South-East region of Haryana. This region is also known for its protruding land structure consisting volcanic, felsite and granitic rocks in plane. Further, exhalation (Jw) ratio from wall and floor comparison has been plotted for each selected village dwelling to identify the high radon emanating source (building material) from the study region. All those measured factors might be useful in building construction code development and selection of material to be used in construction.

Seasonal variability of equilibrium factor and unattached fractions of radon and thoron in different regions of Punjab, India.

A survey was conducted to estimate equilibrium factor and unattached fractions of radon and thoron in different regions of Punjab state, India. Pin hole based twin cup dosimeters and direct progeny sensor techniques have been utilized for estimation of concentration level of radon, thoron and their progenies. Equilibrium factor calculated from radon, thoron and their progenies concentration has been found to vary from 0.15 to 0.80 and 0.008 to 0.101 with an average value of 0.44 and 0.036 for radon and thoron respectively. Equilibrium factor for radon has found to be highest in winter season and lowest in summer season whereas for thoron highest value is observed in winter and rainy season and lowest in summer. Unattached fractions of radon and thoron have been found to vary from 0.022 to 0.205 and 0.013 to 0.212 with an average value of 0.099 and 0.071 respectively. Unattached fractions have found to be highest in winter season and lowest in rainy and summer season.

Investigation of bismuth borate glass system modified with barium for structural and gamma-ray shielding properties

In the present paper, transparent and non-toxic Bi2O3-B2O3 glasses doped with BaO have been prepared by the authors which may replace the standard radiation shielding concretes and lead based commercial glasses for gamma ray shielding applications. The effects of BaO on the structural and optical properties of the prepared glass system have been investigated by Raman, FTIR and UV-Visible techniques. It has been observed that barium plays the role of a modifier and it is responsible for conversion of triangular [BO3] units to tetrahedral [BO4] units along with formation of non-bridging oxygen and increase in ionic character. It also improves the radiation shielding abilities of the glass system. The mass attenuation coefficients for gamma-ray photons at 662 keV energy by using 137Cs radioactive source have been measured by employing narrow beam transmission geometry. This was accompanied by theoretical computation of mass attenuation coefficients in the wide photon energy range varying from 1 keV to 100 GeV. It has been found that values of mean free path and tenth value layer decrease whereas, density and effective atomic number increase with the increase of barium oxide content. As compared with barite concrete and commercial shielding glass RS-360, our prepared Bi2O3 - BaO - B2O3 glasses have shown better gamma ray shielding properties. This implies that the prepared glass system is a better gamma ray absorber and it has the potential for use in gamma-ray shielding applications.

INVESTIGATION OF THERMOLUMINESCENCE CHARACTERISTICS OF Y2O3:Er3+ NANOPHOSPHORS.

Thermoluminescence (TL) characteristics of Y2O3:Er3+ nanophosphor exposed to UV radiations were investigated. Combustion synthesis method was employed to synthesise the nanophosphors. The confirmation for the pure cubic phase was done by powder X-ray diffraction. The particles formed were found to have 23.19 nm size and it was calculated by the Debye-Scherrer formula for [222] plane and is in close agreement with those obtained using transmission electron microscopy analysis. scanning electron microscopy micrograph reveals porous, irregular shaped particles with large agglomeration of particles whereas Fourier transform infrared spectroscopy studies confirm the presence of organic residua OH and CO in the samples. TL characteristics of UV irradiated Y2O3:Er3+ for (1-5) mol % were investigated. All the TL glow curves show almost similar glow curves having a single broad peak at 113.26, 113.82 113.72, 113.74 and 113.72°C for 1, 2, 3, 4 and 5 mol %, respectively, of Er3+ ions. The effects of heating rate were also studied and the trapping parameters, namely activation energy (E), order of kinetics (b) and frequency factor (s) were determined using Chens peak shape method and computerised glow curve deconvolution technique suggested by Kitis for second-order kinetics. They were also discussed in detail for their possible usage in dosimetry.

Measurement of Indoor Radon, Thoron and Their Progeny Concentrations in the Dwellings of District Hamirpur, Himachal Pradesh, India

In the present investigation indoor radon (222Rn), thoron (220Rn) and their progeny concentrations have been measured in the wide range of dwellings from 12 different villages of Hamirpur district, Himachal Pradesh, India by using LR-115 type-II based Pin-hole Radon-Thoron discriminating twin cup dosimeters, direct radon and thoron progeny sensors (DRPS/DTPS). As inhalation doses are predominantly due to daughter products of radon and thoron and not due to gases, it is important to measure the decay products directly for health risk assessments. In the study region different types of houses were selected randomly according to methodologies described by Radiological Physics and Advisory Division (RPAD), Bhaba Atomic Research Centre (BARC), Mumbai. The indoor radon concentrations in these villages have been found vary from 36.1 to 272 Bq/m3, with average value of 125.54 Bq/m3 and for thoron vary from 38.5 to 331 Bq/m3, with average value of 140 Bq/m3. The progeny concentrations of radon and thoron are found within the limits of 10.5 to 106.9 Bq/m3 and 0.9 to 6 Bq/m3 respectively, with average values 43.7 Bq/m3 and 3.34 Bq/m3 respectively. The average concentration values observed in these dwellings have been found within the safe limits as recommended by International Commission on Radiological Protection (ICRP) and United Nation Scientific Committee on the Effect of Atomic Radiation (UNSCEAR).

Perspectives Revisited - The Buccal Cytome Assay in Mobile Phone Users

Abstract Buccal cell preparations previously scored for micronuclei were re-investigated for genomic instability and other biomarkers to assess DNA damage, cell-proliferation and cell-death in healthy mobile phone users (n=25; 30.96±2.09y) using mobile phones for 3-5y and the non-mobile phones users (n=25; 32.28±2.01y) according to the buccal micronucleus cytome (BMCyt) assay which was then not available. The frequency of micronuclei (13.66x), nuclear buds (2.57x), basal (1.34x), karyorrhectic (1.26x), karyolytic (2.44x), pyknotic (1.77x) and condensed chromatin (2.08x) cells were highly significantly (p=0.000) increased in mobile phone users whereas the binucleated cells (4.03x) and repair index (8.36x) showed significant decrease (p=0.000). DNA damage and nuclear anomalies scored in BMCyt assay are indicative of genetic damage that has not been repaired and this may predispose the mobile phone users to malignancy and cytotoxicity ramifications. Therefore, despite the benefits of communication technology, measures need to be taken so that better connectivity is not at expense of health.