Natural radionuclide assessment of soil from Tasik Paya Bungor, Gambang. / Izzah Amirah Hazlinda Medar

The environment is definitely exposed to radiation. There are many sources that
contribute to the natural background; one of them is natural radionuclides.
Radionuclides are including Uranium-238 (238U), Thorium-232 (232Th) and
Potassium-40 (40K) with an unstable nucleus. The concentration of naturally
occurring radionuclides materials (NORM) in the surrounding may cause by human
activities such as agricultures activities, fertilizers and fossil fuels combustion. The
unexpected exposure to radionuclides usually will affect the living organisms
including human health in long term effect. The study was done to know the
concentration of naturally occurring radioactive material (NORM) in the soil aside
from to find the radiological risk in Tasik Paya Bungor, Gambang. The sample was
collected by using hand auger and then survey meter is used to obtain the absorbed
dose rate of that place. The concentration of 238U, 232Th, 4<1<. were obtained by using
EDXRF are 67.80 ± 11.87 Bq / kg, 149.74 ± 15.76 Bq / kg and 543.10 ± 16.34 Bq /
kg respectively. The results obtained are higher than the concentrations of world limit
for 238U, 232Th and 40K which are 33 Bq kg-I, 40 Bq kg-I and 420 Bq kg-I,
respectively. For the radiological risk studied in Tasik Paya Bungor, Gambang area
are based on the radium equivalent activity, absorbed dose rate, annual effective dose
and external hazard index. The mean averages of the radiological risks are 323.76 Bq
kg-I, 151.44 nGy / yr, 0.186 mSv / yr and 0.874 Hex respectively. The results obtained
are averagely lower compared to the world limit for the radium equivalent activity,
absorbed dose rate, annual effective dose and external hazard index which are 370 Bq
kg-I, 58 nGy / yr, 0.3 mSv / yr and 1 Hex respectively. Finally, the isodose map was
generated by using Surfer 15 software.