Natural radioactivity in select metamorphic and sedimentary rocks of the Opava Mountains (Poland)

rocks from the Opava Mountains region (Eastern Sudetes, Poland) as
measured in the laboratory and under in situ field conditions. Activity
concentrations for 232Th, 238U, and 40K were obtained using an HPGe
gamma-ray spectrometry system. Activities for 232Th ranged from 2
to 39 Bq kg−1 as measured in the laboratory and from 5 to 38 Bq kg−1
measured under in situ field conditions. For 238U, the activity
concentrations ranged from 4 to 37 Bq kg−1 in the laboratory and from
7 to 42 Bq kg−1 under in situ field conditions. For 40K, activity
concentrations ranged from 12 to 820 Bq kg−1 in the laboratory and
from 60 to 826 Bq kg−1 under in situ field conditions. Measured
activity concentrations were compared with average activity
concentrations of radionuclides in similar types of rocks from
different global localities. The in situ field measurement and
laboratory measurements did not show significant differences
indicating that both methods provide reliable 232Th, 238U, and 40K
results for different lithologies.