Measuring Radionuclides Concentration in Rice Field Soils Using Gamma Spectroscopy in Northern Iran

Background: a few elements of soil are radioactive. soil can transfer radionuclide into plants feeding human. some- times their levels are as high as to be concern of human healthy. rice has an important share for iranian foods espe- cially in north of iran. therefore we decided to obtain radionuclides concentration emitting g rays in lahijan city (northern iran) rice fields using γ spectroscopy. methods: twenty eight samples from rice field's soils and 12 samples from superficial soils were collected at a square of 10*10 m2 to get 2kg weight. to make dry samples were put into oven at 105°c for 24h. then they were milled and 950 gr of each sample was transferred to marinelli container with 1000cc volume, sealed and left for 40 days to get secu- lar equilibrium. after measuring ph, electric conductivity and organic carbon, g spectroscopy was done to get sample gamma spectrum at 2000-6000 sec using hpge detector. results: it was found 226ra activity in rice fields of 29.273±0.72 bqkg-1 and city soil of 31.02±1.1 bqkg-1 and also 232th activity of 37.47±1.12 bqkg-1 for rice fields’ soils and 40.47±1.68 bqkg-1 for city soil were in standard mode. conclusion: 40k activities mean value according to unscear; 2000 was found a little greater than standard. a little value of 137cs was found in lahijan rice fields and city soils that could be as a result of chernobyl accident. in except of 137cs, for three other under studied city soil elements, activities were greater than that of rice fields.