Activity Concentration of 238U, 232Th and 40K Based on Soil Types in Perak State, Malaysia

The activity concentrations of 238U, 232Th and 40K in soil samples from different soil types has been collected in the state of Perak, Malaysia. The samples were determined using a high resolution co-axial HPGe gamma ray spectrometry system. Mean values for 238U, 232Th and 40K activity concentrations were found to be (127 ± 97) Bq kg-1, (304 ± 28) Bq kg-1, and (302 ± 29) Bq kg-1 respectively. The highest concentration of 238U and 232Th was found for soil of the types Paleudults-Hapludults and 40K for the typic Aeric Tropaquepts. The external hazard values (Hex) are between 0.35 and 3.07. Soil type typic Paleudults and typic Hapludults have a hazard index, Hex value which is greater than 2, and the rest of the soil types (ten soil types) have Hex values between 1 to 2. The concentrations of 238U and 232Th in soil samples in the study area are higher than the reference value.