A survey of natural radiation levels in soils and rocks from Aliaga-Foca region in Izmir, Turkey

The gamma spectroscopic analysis of Ra-226, Th-232 and K-40 has been carried out in surface soil samples collected from Aliaga-Foa industrial region. The rock samples as parent materials of the soils are also collected and analysed for relevant radionuclides in order to evaluate the natural radiation levels. In the present study, the mean activity concentrations and ranges of the related radionuclides in the soil samples from 60 sites distributed all over the region are as follows: Ra-226 is 38 (14123) Bq kg(1); Th-232, 63 (27132) Bq kg(1) and K-40, 633 (1411666) Bq kg(1). Meanwhile, the ranges of natural radionuclide activities in the rock samples characterising the region are 4195 Bq kg(1) for Ra-226, 10122 Bq kg(1) for Th-232 and 2641470 Bq kg(1) for K-40, respectively. Based on the available data, the radiation hazard parameters associated with the surveyed soils/rocks are calculated and the results do not exceed the permissible recommended values except for soils originated from Foa rhyolites and tuffs. Furthermore, the collected data allowed for the mapping of the measured activities and corresponding gamma dose rates.