Radon exhalation rate and natural radionuclide content in building materials of high background areas of Ramsar, Iran.

Radon exhalation rates from building materials used in high background radiation areas (HBRA) of Ramsar were measured using an active radon gas analyzer with an emanation container. Radon exhalation rates from these samples varied from below the lower detection limit up to 384 Bq.m(-2) h(-1). The (226)Ra, (232)Th and (40)K contents were also measured using a high resolution HPGe gamma- ray spectrometer system. The activity concentration of (226)Ra, (232)Th and (40)K content varied from below the minimum detection limit up to 86,400 Bq kg(-1), 187 Bq kg(-1) and 1350 Bq kg(-1), respectively. The linear correlation coefficient between radon exhalation rate and radium concentration was 0.90. The result of this survey shows that radon exhalation rate and radium content in some local stones used as basements are extremely high and these samples are main sources of indoor radon emanation as well as external gamma radiation from uranium series.

Terrestrial outdoor exposures in the south-west Caspian region.

Natural radionuclides (40)K, (232)Th and (238)U present in soil and anthropogenic (137)Cs a fission product released to the environment mainly through atmospheric testing of nuclear arms and accidents in nuclear installations are the major contributors to terrestrial outdoor exposures. As part of a comprehensive study of environmental radioactivity in the south Caspian region, soil inventories of these radionuclides have been measured in more than 50 locations throughout Guilan, a northern province of Iran with the highest population density. In the case of natural radionuclides, outdoor absorbed dose rates in air have been inferred from concentrations of radionuclides in soil on the basis of which annual effective dose values have been estimated using the method described in UNSCEAR 2000. Calculation of (137)Cs contribution to dose has been performed by considering its soil inventory profiles and associated numerically estimated photon fluxes at 1 m above the ground. Maps representing the contribution of natural and anthropogenic radionuclides to annual effective dose in the study area have been produced using relevant geostatistical technique. Combined annual effective dose equivalent ranges from 33.1 ± 4.9 to 91.9 ± 16.5 µSv · y(-1) with a mean value of 64.7 ± 15.2 µSv · y(-1).

Measurement of 210Po in Iranian smokers' and non-smokers' teeth.

Thirty human tooth samples were collected from smoker and non-smoker groups with different ages and different sexes from north of Iran. The samples were analysed by a radiochemical procedure, and the prepared source by spontaneous electrolysis was measured by an alpha spectrometry to determine activity concentrations of (210)Po in teeth. The results indicated that the average (210)Po concentration in Iranian human teeth is 3.94 +/- 2.38 mBq g(-1.) The measured mean activity concentrations of (210)Po in smokers' and non-smokers' teeth were 5.89 +/- 3.59 and 2.55 +/- 1.00 mBq g(-1), respectively. The detailed analysis of 30 tooth samples of Iranian population revealed that smoking habits and age may have some influence on (210)Po content in teeth, although this is not the case of difference in sex.