The Study of Natural Radiation Distribution in Soil of São Bernardo do Campo.

We have studied the distribution of natural radioactivity in the soil of five sites of the city São Bernardo do Campo, São Paulo, Brazil. The main contribution of the radiation dose is due to the isotope 40K, with smaller contributions from the elements of the series of 238U and 232Th. The results indicate the dose in all of the studied areas is around the average international dose due to external exposure to gamma rays (0.48 mSv/yr) proceeding from natural terrestrial elements. [ABSTRACT FROM AUTHOR]