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Christa E.P.,Center for Advanced Research in Physical science | Jojo P.J.,Center for Advanced Research in Physical science | Jojo P.J.,University of Malaya | Vaidyan V.K.,Center for Advanced Research in Physical science | And 2 more authors.
Radiation Protection Dosimetry | Year: 2012

A systematic radiological survey has been carried out in the region of high-background radiation area in Kollam district of Kerala to define the natural gamma-radiation levels. One hundred and forty seven soil samples from high-background radiation areas and five samples from normal background region were collected as per standard sampling procedures and were analysed for 238U, 232Th and 40K by gamma-ray spectroscopy. External gamma dose rates at all sampling locations were also measured using a survey meter. The activities of 238U, 232Th and 40K was found to vary from 17 to 3081 Bq kg -1, 54 to 11976 Bq kg -1 and BDL (67.4 Bq kg -1) to 216 Bq kg -1, respectively, in the study area. Such heterogeneous distribution of radionuclides in the region may be attributed to the deposition phenomenon of beach sand soil in the region. Radium equivalent activities were found high in several locations. External gamma dose rates estimated from the levels of radionuclides in soil had a range from 49 to 9244 nGy h -1. The result of gamma dose rate measured at the sampling sites using survey meter showed an excellent correlation with dose rates computed from the natural radionuclides estimated from the soil samples. © The Author 2011. Published by Oxford University Press. All rights reserved. Source


Pereira C.E.,Center for Advanced Research in Physical science | Vaidyan V.K.,Center for Advanced Research in Physical science | Sunil A.,Center for Advanced Research in Physical science | Byju S.B.,Center for Advanced Research in Physical science | And 3 more authors.
Indian Journal of Pure and Applied Physics | Year: 2011

Building materials are one of the potential sources of indoor radioactivity because of the naturally occurring radio nuclides in them. External as well as internal exposures are the two pathways of radiation dose imparted to the human beings from the building materials. Natural clay is the main raw material for the production of bricks and tiles. In the present study, samples of cement, bricks, floor and wall tiles have been analyzed for the primordial radio nuclides namely, uranium, thorium and potassium using gamma ray spectrometry. Radon exhalation rates of these materials were also measured. Among the samples analyzed, the minimum radium equivalent activity was found in bricks (66.08 Bqkg-1) and the maximum was found in cement (225.46 Bqkg-1). External gamma dose, effective dose equivalent, internal and external hazard indexes resulting from the radio nuclides were also determined. The radon exhalation rates from building materials were found to vary between 10.5±2.8 and 82.8±8.2 mBqh-1m-2. Source


Ben Byju S.,Center for Advanced Research in Physical science | Sunil A.,Center for Advanced Research in Physical science | Reeba M.J.,Center for Advanced Research in Physical science | Christa E.P.,Center for Advanced Research in Physical science | And 4 more authors.
Iranian Journal of Radiation Research | Year: 2012

Background: The South-west coast of India is known to have very high levels of natural background radiation due to the monazite beach sand. Uranium is the heaviest trace element found in all terrestrial substances at varying levels with chemical and radio toxicities. It supports several short-lived radioisotopes in its decay series including radium. Uranium in drinking water is important in terms of the ingestion dose. Materials and Methods: The present study reports the results of uranium analysis of 346 drinking water samples from the three costal districts of Kerala using fission track registration technique. Results: Results obtained show that uranium concentrations vary from 0.31 μg/l to 4.92 μg/l equivalent to the specific activity of 3.9 Bq/m3 and 62 Bq/m3, respectively. Conclusion: The estimated daily intake of uranium through drinking water is lower than the recommended limits. The distribution of uranium in water bodies shows a heterogeneous nature of distribution. Source


Wilson E.V.,Center for Advanced Research in Physical science | Bushiri M.J.,Cochin University of Science and Technology | Vaidyan V.K.,Center for Advanced Research in Physical science
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

Urinary stones resected from urinary bladders of patients hailing from Kollam district of Kerala State, India were analyzed by SEM, XRD and by thermal analysis techniques. The analytical results indicate that, stones have different composition, i.e., calcium phosphate, calcium phosphate hydroxide and sodium calcium carbonate. Infrared spectral studies also reveal the presence of phosphates or carbonates in these samples. Further, IR spectral investigations have revealed that amorphous carbonated species are occupied in PO 4 sites in calcium phosphate type stone and OH sites in calcium phosphate hydroxide sample. Thermal studies of these samples also reveal that, carbon dioxide is released from carbonated samples upon heating which is related to amount of carbon content and bond strength. Crystals with defects and irregular morphology are grown inside the urinary bladder due to variation in crystal growth conditions. © 2010 Elsevier B.V. Source


Sunil A.,Center for Advanced Research in Physical science | Byju S.B.,Center for Advanced Research in Physical science | Jojo P.J.,Center for Advanced Research in Physical science | Ramachandran T.V.,Center for Advanced Research in Physical science | Ramachandran T.V.,Bhabha Atomic Research Center
Asian Journal of Chemistry | Year: 2010

Uranium is the ubiquitous heaviest radioactive element found in all terrestrial substances in different level and is important because of its chemical and radioactive properties. Water comes into contact with minerals under the earth's surface and uranium is transferred into water due to its leaching property. Studies on levels of uranium in water bodies will help to understand the mobilization of the tracer amount of uranium in the ecosystem. Water samples from various water sources distributed around the high background region of south India were collected and analyzed for uranium, using dry fission track registration technique, capable of determining the uranium levels even in sub-ppb (particles per billion) level. It is observed that the concentration of uranium is high in seawater as compared to that in tap water. Present work discusses the methods of measurements and the results obtained in detail. From the measured concentration of uranium in water samples, ingestion dose were calculated for an individual using the dose coefficients. Source

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