Natural radioactivity in the soils of some eastern counties of Hungary.

Soil samples were collected from six East-Hungarian counties at 98 different sites and the radionuclides (238)U, (226)Ra, (232)Th and (40)K were determined in these samples by gamma spectrometry. The means and ranges of the activity concentrations obtained for the above isotopes were 33.3 (6-68), 29.7 (10-61), 32.1 (9-56) and 418 (218-670) Bq kg(-1) (dry mass), respectively. Significant differences between certain counties were revealed. (226)Ra/(238)U activity ratio <1 was found at near-river sites lying on the plain terrain. The results were compared with those of the only nationwide survey published for Hungary till now. The mean activity concentrations obtained in this work for the East-Hungarian counties were slightly lower than those resulted for the whole country in the nationwide survey. Its main reason is possibly the different average geological character of the two areas. The computed mean terrestrial absorbed dose rate in air in the East-Hungarian region is 41.0 nGy h(-1).