distribution of natural radionuclides on coasts of bushehr, persian gulf, iran

a reconnaissance study has been made on the distribution of 238u, 232th, 40k, 137cs andgeochemical features in soil and sediment samples at various locations on the coast of bushehr in the persiangulf. in this study a gamma-ray spectrometer based on a high purity germanium detector and a pc basedmca and x-ray fluorescence (xrf) method were used. estimation of the measured radionuclide contenthave been made for the absorbed dose rate of gamma radiation. the activity concentration (a), the equivalentradium (req), and the external hazard index (hex) which resulted from the natural radionuclides in soil andsediment are also calculated. the base-line data of radionuclides and heavy metals in view of thecommissioning of nuclear and non-nuclear industries for the coast of bushehr, which does not yet exist, wasobtained.activity concentration levels due to radionuclides were measured in 50 soil and sediment samplescollected from this region. the measurement was performed with respect to their gamma radioactivity for acounting time of 24 hour intervals. from the accumulated spectra, activity concentration were determined for40k (range from 108 to 520 bq kg-1), 137cs (from 6 to 40 bq kg-1), 238u (from 12 to 75 bq kg-1) and 232th(from 8 to 33 bq kg-1) with the lowest limit detection (lld) of, respectively, 68, 3.2, 4.3 and 4.3 bq kg-1.the dose rate from ambient air at the soil ranges was between 14 to 44 ngy h-1 with an average of 30.56±7.86 ngy h-1.