title: Natural radioactivity measurements in beach-rock samples of south-east coast of Tamilnadu, India.
abstract: The concentration of primordial radionuclides in beach-rock samples of the south-east coast of Tamilnadu, India has been measured using gamma ray spectrum of rock. The mean activities of 232Th, 238U and 40K are 144.18, 29.25 and 267.48 Bq kg(-1) respectively. In situ measurements were also carried out using environmental radiation dosemeter. The linear correlation coefficient was obtained. The average activity of concentration of 232Th in the present study is 2.5 times higher than the world median value while the activity of 238U and 40K were found to be lower. This may be due to the heavy minerals present in the study area. In the present study, the calculated activity ratio (Th/U) is higher than the crustal rocks. This may be due to changes in the crustal composition through time (mafic to felsic) that are reflected by a change in the Th and U abundances in sedimentary rocks, and also increase in carbon content with time resulted in the decrease in U content and increase in Th/U ratio.
authors.affiliation: Department of Physics, Annamalai University, Annamalai Nagar, 608 002, India. srsaranram@rediffmail.com
authors.forename: V
authors.initials: V
authors.lastname: Ramasamy
authors.forename: M
authors.initials: M
authors.lastname: Dheenathayalu
authors.forename: R
authors.initials: R
authors.lastname: Ravisankar
authors.forename: V
authors.initials: V
authors.lastname: Ponnusamy
authors.forename: G Victor
authors.initials: GV
authors.lastname: Rajamanickkam
authors.forename: DajKumar
authors.initials: D
authors.lastname: Sahayam
authors.forename: V
authors.initials: V
authors.lastname: Meenakshisundram
authors.forename: V
authors.initials: V
authors.lastname: Gajendran
mesh_terms: D001417:Background Radiation; D005843:Geography / Q000379:methods; D019015:Geologic Sediments / Q000032:analysis*; D007194:India / Q000453:epidemiology; D011829:Radiation Dosage; D011868:Radioisotopes / Q000032:analysis*; D011874:Radiometry / Q000379:methods*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive