Keywords: body burdens, high level background radiation area, HLBRA, Iran, radionuclides, Ramsar, low radiation, public exposure, natural radiation, polonium-210, lead-210, foodstuffs, food
Radionuclide content of human samples in the Ramsar area of Iran
As part of a survey to determine public exposure to natural radiation and to estimate radionuclide levels in the diet and human tissues, the radionuclide content of different biological samples of residents in Ramsar, a high level background radiation area (HLBRA) in Iran, has been measured. The main route of 210Po and 210Pb intake in the human body is ingestion via foodstuffs. The absorption of 210Po into the blood from the digestive system was estimated to be 30–40%. The highest concentrations of 210Po and 210Pb in the body were accumulated in the skeleton and hair. The average 226Ra in ashed bone samples was 30.02 fci. A surprisingly high 210Po content was found in human hair, with levels of 0.182 P cig-1 and 0.161 P cig-1 in nine males and six females, respectively. The calculated annual radiation doses of 210Po in the bone, liver and kidneys was 2.5–4.5 mrad.a-1 and in other soft tissues 0.4–0.8 mrad.a-1. The mean concentration of 210Po in 100 ml of urine was 2.00 (±0.86 SE) mBq and for control samples was 0.86 (±0.03 SE) mBq. It is concluded that the 210Po concentration in residents is significantly elevated in proportion to background levels but so far there is no evidence of health problems arising from this.