title: The importance of physico-chemical parameters on the speciation of natural radionuclides in riverine ecosystems.
abstract: External gamma radiation levels were measured in the catchment areas of the Sharavathi River and the dose rates in air were found to be in the range 26.0-61.0 nGy h(-1). Soil and sediment samples of the riverine environment were analysed for natural radionuclides such as (226)Ra, (232)Th and (40)K using a NaI(Tl) gamma spectrometer. The activity concentration of (210)Pb and (210)Po in soil and sediment samples was determined by radiochemical separation techniques. Evaluation of the activity concentration of radionuclides with grain size revealed an increase in the activity of (226)Ra, (232)Th and (40)K towards fine grain size. The activity concentrations for all isotopes in all samples were not significantly correlated with pH. However, the activity of (210)Po and (210)Pb in sediment showed a moderate positive correlation with organic matter content and a good correlation with clay content of sediment.
authors.affiliation: Department of Studies in Physics, Mangalore University, Mangalagangotri, India. narayanay@yahoo.com
authors.forename: Y
authors.initials: Y
authors.lastname: Narayana
authors.forename: K M
authors.initials: KM
authors.lastname: Rajashekara
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D017753:Ecosystem; D005720:Gamma Rays; D019015:Geologic Sediments / Q000737:chemistry; D007856:Lead Radioisotopes / Q000032:analysis / Q000737:chemistry; D011059:Polonium / Q000032:analysis / Q000737:chemistry; D011197:Potassium Radioisotopes / Q000032:analysis / Q000737:chemistry; D011834:Radiation Monitoring; D011886:Radon / Q000032:analysis / Q000737:chemistry; D045483:Rivers / Q000737:chemistry*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013910:Thorium / Q000032:analysis / Q000737:chemistry
chemical_list: D000396:Air Pollutants, Radioactive; D007856:Lead Radioisotopes; D011197:Potassium Radioisotopes; D012990:Soil Pollutants, Radioactive; D013910:Thorium; D011059:Polonium; D011886:Radon