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  Citation statistics : Table of Contents
   2016| January-March  | Volume 39 | Issue 1  
    Online since July 1, 2016

 
 
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ORIGINAL ARTICLES
A study of radon concentration in drinking water samples of Amritsar city of Punjab (India)
Ajay Kumar, Manpreet Kaur, Sumit Sharma, Rohit Mehra
January-March 2016, 39(1):13-19
DOI:10.4103/0972-0464.185155  
Radon concentration has been estimated in drinking water samples of 17 selected locations in Amritsar city of Punjab, India. RAD7, an electronic solid state radon monitor has been used to evaluate the radon concentration in collected drinking water samples. The corresponding annual mean effective dose for ingestion and inhalation was calculated according to parameters introduced by UNSCEAR (2000) report. The radon concentration in drinking water samples has been found to vary from 0.53 ± 0.11 to 11.20 ± 1.40 Bql−1 . The values of radon concentration in these samples were found below the recommended limit proposed by USEPA (1991) and European Commission (2001). The range of calculated annual effective dose varied between 1.45 and 30.57 ΅Svy−1 . These values lie well within the safe limit prescribed by the WHO (2003) and European council (2005). The purpose of this study was to assess the radiological risk, if any, to human health due to consumption of drinking water that is available at Amritsar city.
  14 2,179 322
Estimation of indoor and outdoor effective doses and lifetime cancer risk from gamma dose rates along the coastal regions of Kollam district, Kerala
S Monica, AK Visnu Prasad, SR Soniya, PJ Jojo
January-March 2016, 39(1):38-43
DOI:10.4103/0972-0464.185180  
The exposure of human beings to ionizing radiation from natural sources is a continuously inescapable feature of life on earth. Direct measurement of absorbed dose rates in air has been carried out in many countries of the world during the last few decades. Such investigations are useful for the assessment of public dose rates. Indoor and outdoor gamma dose rates were evaluated along the coastal regions of Kollam district, Kerala, through direct measurement using portable gamma dosimeter, and analysis of soil sample for activity of 238 U, 232 Th, and 40 K concentration was carried out using gamma spectroscopy. Indoor and outdoor exposure rates, the annual effective dose (AED), and lifetime cancer risk of residents along the coastal regions of Kollam district, Kerala, were evaluated. The reduction coefficients were also calculated for the region. The mean indoor effective dose due to background gamma along the coastal region of Neendakara panchayath was found to be 7.56 mSvy−1 which is larger as compared with the worldwide average of the AED of 0.48 mSv y−1  and the outdoor mean effective dose of 4.83 mSvy−1 . Estimated excess lifetime cancer risk (ELCR) from indoor AED equivalent ranges from 22.56 to 26.46 × 10−3 and ELCR from outdoor ranges from 14.95 to 16.65 × 10−3 . Excess average lifetime cancer risk estimate from all the values is found to be 20.56 × 10−3 , which is larger compared with the resulting worldwide average 0.25 × 10−3 .
  7 2,015 360
Radiation shielding of polymer composite materials with wolfram carbide and boron carbide
Alparslan Erol, Isa Pocan, Emre Yanbay, Onur Alp Ersoz, Fatma Yurt Lambrecht
January-March 2016, 39(1):3-6
DOI:10.4103/0972-0464.185147  
In general, lead is used as shielding material for protection against radiation. In spite of its high density, lead is toxic and lead aprons are very heavy for personal shielding. Thus, there is a need for nontoxic, light, and environmental friendly radiation-shielding materials. Polymers cannot be effective against gamma radiation on their own. High-density metal wolfram carbide could be useful against gamma radiation, and boron carbide could also be useful for neutron shielding. In this study, high-density polyethylene, boron carbide, and wolfram carbide can be mixed in certain amounts and composite discs can be obtained in this way. According to results, a new shielding material is efficient for gamma radiation.
  6 3,796 752
Distribution of natural uranium in groundwater around Kudankulam
BS Selvi, B Vijayakumar, BK Rana, PM Ravi
January-March 2016, 39(1):25-29
DOI:10.4103/0972-0464.185164  
A systematic study was carried out to estimate the uranium concentration in the ground water around Kudankulam in Southern Tamil Nadu. The uranium concentration in ground water varies from 0.2 to 6.6 μg/l, with a mean value of 2.0 μg/l. The Quantalase uranium analyzer was used to measure the uranium concentration. These groundwater samples were analyzed for the water quality parameters such as pH, conductance, total dissolved solids (TDS), salinity, chloride, and sulfate. An attempt has been made to correlate the uranium concentration with the water quality parameters. It is observed that conductance, TDS, salinity, chloride, and sulfate show positive correlation with uranium concentration.
  4 1,239 232
Estimation of roughness length Z0 for Kalpakkam site
T Jesan, C Manonmani, J Thulasi Brindha, S Rajaram, PM Ravi, RM Tripathi
January-March 2016, 39(1):44-47
DOI:10.4103/0972-0464.185182  
The accurate knowledge of the surface topographic parameters, which represent terrain characteristics of a site, is required in atmospheric dispersion modeling. The rough surface retards the wind flow from a smooth surface, which results in sharp decrease in wind speed, change in vertical profile along with atmospheric stability. Dispersion models require extrapolation of wind speed URef at measured height ZRef to the wind speed UStack at stack height ZStack , based on power law wind profile. Wind speed profile can be evaluated using site specific surface scaling parameters roughness length Z0 and friction velocity U* . In this paper, sector dependent Z0 and U* for Kalpakkam site is evaluated for neutral category and the sector values of Z0 are explained according to the terrain features. The maximum and minimum Z0 was observed in SSE (0.84 m) and N (0.26 m) upwind sectors due to the presence of more number of residential buildings, sand dunes, and high traffic, in contrast to N sector where mostly agricultural farming lands are present. The site specific wind speed profile index P is calculated based on Z0 for different sectors leads to better estimation of annual dilution factor and gamma dose on the part of neutral category computation. The surface scaling parameter mean surface drag coefficient CD was estimated to be 0.16, which implies urban environment at Kalpakkam site.
  1 1,042 176
Evaluation of tritium dispersion in the atmosphere by Risψ Mesoscale Puff modeling systems using on-site meteorological parameters for the nuclear site Tarapur, India
Vedesh K Varakhedkar, A Baburajan, SV Vanave, DD Rao, PM Ravi, RM Tripathi
January-March 2016, 39(1):30-37
DOI:10.4103/0972-0464.185172  
Dispersion models are important predictive tools that are used to simulate the way the atmosphere transports and diffuses contaminants from industrial sources of pollution. Risψ Mesoscale Puff (RIMPUFF) modeling system is used to simulate the radioactive H-3 released into the atmosphere through stack height of 100 m from a Tarapur Atomic Power Station 3 and 4 (TAPS 3 and 4) to predict downwind tritium ambient air concentrations in the environment around nuclear power plants. The tritium air concentrations by field measurement (measured tritium air concentrations using bubbler setup in the areas adjacent to TAPS 3 and 4, a pressurized heavy water reactor [PHWR]) were compared with that by calculation to validate the modeling system RIMPUFF for the Tarapur site. The computed and measured atmospheric tritium concentrations were quite consistent in trend and magnitude and the value of fractional bias computed is − 0.2524 (i.e., model predictions are within a factor of 2). This RIMPUFF modeling system will be useful in reviewing and evaluating environmental radiological impacts for PHWRs, especially it will be of great help to predict the behavior of tritium in the atmospheric environment around nuclear power plants during emergencies. Tritium concentrations in ambient air computed and measured at various locations around TAPS 3 and 4 showed a best fit regression line passing through the origin as Y (computed concentration) = 0.6725 X (measured concentration) with correlation coefficient of 0.75.
  1 634 134
EDITORIAL
Computation of excess lifetime cancer risk for environmental exposures: Is it needed? - An opinion
DD Rao
January-March 2016, 39(1):1-2
DOI:10.4103/0972-0464.185136  
  - 949 230
NEWS AND INFORMATION
Brief Report on the 32 nd IARP International Conference : IARPIC-2016
MS Kulkarni, DD Rao
January-March 2016, 39(1):48-50
DOI:10.4103/0972-0464.185183  
  - 804 136
ORIGINAL ARTICLES
Radiological safety survey of medical radiographic equipment
Kofi Ofori, Emmanuel Ofori Darko, Isaac Owusu
January-March 2016, 39(1):7-12
DOI:10.4103/0972-0464.185151  
The areas of concern in a medical X-ray equipment are the focal spot, filtration, collimation, kVp calibration, timer accuracy, and exposure linearity, alignment of tube and image receptor, all of which impact exposure. This paper presents an analysis of historical data on 284 X-ray equipment over a 5-year period based on field measurements using well-defined protocols prepared by the National Regulatory Authority responsible for regulating the activities of users of ionizing radiation nationwide. All the data were collected and recorded for posterior analysis and subsequent preparation of quality control reports to be submitted to clients. The safety parameters assessed were the kVp accuracy, mA linearity, half-value layer, collimation accuracy, X-ray/light beam perpendicularity, and the timer accuracy. An electronic parameter such as the kVp which is important not only for radiation protection, but also for image quality showed significant improvements. Again, only 57% of conventional X-ray systems showed kVp conformity in 2010, a percentage that improved to 89% in 2014. Mobile X-ray systems showed an increase in this conformity index from 50% in 2010 to 84% in 2014. All these improvements were attributed to the continuous and extensive enforcement of the provisions of the legislation (Legislative Instrument 1559, Ghana, 1993).
  - 1,137 205
Estimation of diurnal variation of surface layer at Tarapur site using ultrasonic anemometer
Vedesh K Varakhedkar, SV Vanave, A Baburajan, PM Ravi, RM Tripathi
January-March 2016, 39(1):20-24
DOI:10.4103/0972-0464.185159  
Surface layer (SL) is defined by the region above the earth surface (50-100 m) wherein shearing stress is approximately constant with height, and the wind structure is primarily determined by the nature of the surface and the vertical gradient of temperature. During day time due to convection, variation in shear stress with height is less and hence the SL heights are higher and conversely during nights decrease in shear stress with height is higher and hence SL heights are lower. SL height is decreasing with increase in the stability and also SL heights are higher for lower values of for any stability category. Hourly average SL heights for Tarapur site varied from 40 to 142 m with = 0.1. Estimation of SL height for the site will be useful input parameter for the dispersion models.
  - 534 96
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