Derived intervention levels for edible parts of foodstuffs consumed in Iran.

Measures to protect the public following an accidental release of radionuclides to the environment will depend on the circumstances including the extent of the potential hazards. The projected level of risk is an important precondition in emergency planning. The levels can be expressed in terms of concentration levels in the environment or in foodstuffs. These derived intervention levels (DILs) can be determined for the range of important radionuclides that could be released to the environment in the event of a nuclear accident. Derived intervention levels for 90Sr, 131I, 134Cs + 137Cs, 238Pu + 239Pu + 241Am and 103Ru + 106Ru radionuclide groups were calculated for the most consumed foodstuffs in Iran. These nine radionuclides are expected to deliver the major portion of the radiation dose during the first year following an accidental episode of radiological food contaminations. Calculations for DILs were based on recommendations from international and national organizations and average food consumption rate data for Iran. From our research it was found that DILs for foodstuffs consumed in Iran for the above mentioned radionuclide groups (excluding the ruthenium group) are equal to 390, 250, 1000, and 3 Bq kg(-1), respectively.

Assessment of natural radioactivity and the associated hazards in Iranian cement.

This paper presents the finding of a study undertaken to determine natural radioactivity and associated hazards in local types of cement in Iran. A total of 42 samples were collected from various manufacturers and suppliers and analysed using a shielded HPGe gamma-ray spectrometer. The specific activities of 232Th, 226Ra and 40K were measured in samples and results ranged from minimum values of 8, 16, 101 Bq kg(-1) to maximum values of 17, 43 and 141 Bq kg(-1), respectively. On the basis of activity concentration index (I), it could be shown that, the radioactivity of local cement samples was not greater than the established standard values in other countries.

The natural radioactivity in the bricks used for the construction of the dwelling in Tehran areas of Iran.

This paper presents the finding of a study undertaken to determine the natural radioactivity present in bricks in Tehran. A total of 45 samples of commonly used bricks were collected from various manufacturers and suppliers and analyzed using a shielded HPGe gamma ray spectrometer. The specific activities of (226) Ra, (232) Th, and (40) K were measured in all brick samples, and results ranged from minimum values of 26, 24, and 524 Bq kg(-1) to maximum values of 38, 36, and 820 Bq kg(-1) with mean values of 33, 30, and 700 Bq kg(-1) ,respectively. In general, these activities were comparable to the results of similar studies undertaken in another countries. These activities would suggest that the use of such bricks in construction of dwellings or work places in Tehran is unlikely to give rise to any significant radiation exposure to the occupants.

Environmental study of fall-out (239+240)Pu in soil samples in Iran.

The result of a general survey on the concentration of fall-out (239+240)Pu in soil collected from several regions in Iran are presented. The samples represent mixed soil averaged over the depth of 0-50 mm. According to the results obtained by alpha spectrometry on 96 soil samples from 32 locations, the (239+240)Pu concentrations vary in the range 80-360 mBq kg(-1). Under normal operating conditions and present counting setup, the minimum detectable activity (MDA) was approximately 8 mBq kg(-1) for soil samples.

Concentrations of natural radionuclides in imported mineral substances.

Levels of natural radionuclides, such as thorium-232 (232Th), radium-226 (226Ra) and potassium-40 (40K), were determined in about 2,000 samples of imported mineral substances using gamma spectrometry. The maximum concentration levels of 232Th, 226Ra and 40K were 1,260 +/- 54, 13,400 +/- 94 and 1,256 +/- 260 Bq kg(-1), respectively, in zirconium compounds. Due to relatively high concentrations of the above-mentioned radionuclides in some imported mineral substances, the National Radiation Protection Department (NRPD), as the competent authority, has established national limits (900 Bq kg(-1) for 232Th, 1800 Bq kg(-1) for 226Ra and 11,000 Bq kg(-1) for 40K), based on the external exposures, for general importation permits of these materials.