| المستخلص: |
A study of environmental radiation from forty-three different soil, water and plant samples acquired from the North Sharqia Region of Sultanate of Oman is presented. This will provide a baseline data for natural and man-made radioactivity of the area. Due to the lack of radiation data in the region, samples are collected from the headwater and stream of Wadi Dama and Altain. In this study the activity concentration for 226Ra, 232Th, 40K and 137Cs were measured by using a hyper pure germanium (HPGe) detector. The activity profile of radionuclide shows low activity concentration across the collected samples. In the soil samples, the range of activity concentration of 226Ra, 232Th and 40K varies from 5.78±0.02 Bqkg-1 to 15.53±0.02 Bqkg-1, 6.06±0.21 Bqkg-1 to 17.03±0.02 Bqkg-1 and 72.31±0.02 Bqkg-1 to 275.82±0.01 Bqkg-1 with overall average 10.14±0.02 Bqkg-1, 10.83±0.04 Bqkg-1 and 150.47±0.01 Bq.kg-1, respectively. While, in the plant samples the activity concentration ranges from 0.04±0.01 Bqkg-1 to 0.19±0.00 Bqkg-1 for 226Ra, 0.09±0.02 Bqkg-1 to 1.26±0.06 Bq.kg-1 for 232Th and 0.15±0.05 Bqkg-1 to 1.97±0.36 Bqkg-1 for 40K. The average activity concentration in water samples for 226Ra, 232Th and 40K are 0.11±0.01, 0.29±0.03 and 1.02±0.08 Bq.L-1, respectively. In all samples (soil, water and plant) the activity concentration for 137Cs is very low. Radiological parameter such as absorbed dose rate(D), radium equivalent activity (Raeq), annual effective dose equivalent (AEDE), and external (Hex) and internal (Hin) hazard indices were calculated to assess the radiological hazard from the natural radionuclides 226Ra, 232Th and 40K. The average value for absorbed dose rate and the annual effective dose equivalent were calculated for soil samples to be 17.5 nGy.h-1and 21.52 Sv.y-1, respectively. While, for plant samples the calculated absorbed dose rate and annual effective dose are in the range of 1.25 to 45.91 nGy.h-1 and 1.54 to 56.48 Svyr-1, respectively. In the water samples, the calculated average values of annual effective dose due to the water ingestion are 0.0414, 0.0641 and 0.0515 mSvy-1 for infants, children and adults, respectively, which are below the recommended level. The external and internal hazard indices for all samples of soil, water and grass are less than unity. Therefore, the monitored areas are safe and the risk of radiation is insignificant.
|
