Radiometric evaluation and analysis of commonly consumed vegetables in Selangor, Malaysia / Hariandra Muthu

Hariandra , Muthu (2022) Radiometric evaluation and analysis of commonly consumed vegetables in Selangor, Malaysia / Hariandra Muthu. PhD thesis, Universiti Malaya.

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Abstract

The activity concentration of naturally occurring radionuclides in vegetables and peat soil was measured in this research to determine the transfer factors (TFs) of radionuclides from soil to vegetables collected from farms located in Klang, Selangor using a High Purity Germanium Detector. The results showed that the activity concentration ranges for 137Cs (Caesium-137), 226Ra (Radium-226), 232Th (Thorium-232) and 40K (Potassium-40) in the soil of the vegetable were (0.34 – 3.21) Bqkg-1, (2.72 – 46.54) Bqkg-1, (9.01 - 54.84) Bqkg-1and (19.22 – 477.76) Bqkg-1, respectively. The activity concentration ranges for 226Ra, 232Th and 40K in various vegetable samples were (0.41 – 3.41) Bqkg-1, (0.02 - 3.56) Bqkg-1and (16.22 - 317.49) Bqkg-1, respectively. The activity concentration for 137Cs in the vegetable samples were below the detection limit (BDL). The TF from soil-to-plant for 226Ra, 232Th and 40K was in the range of (0.01 - 0.67), (0.00 - 0.17) and (0.26 – 2.52), respectively. The values obtained, including the radium equivalent, Raeq, were compared to the internationally recommended values. Raeq calculated in the soil samples from the vegetable farm are in the range of (17.09 – 161.75) Bqkg-1, which is lower than the suggested value of 370 Bq/kg by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Radiological hazards from the soil and consumer exposure were evaluated using soil and vegetable activity concentrations. It is found that the External Hazard Index, Hex and Internal Hazard Index, Hin are ranged from 0.05 to 0.44 and from 0.05 to 0.56, respectively, which are lower than the limit established by the European Commission of Radiation Protection(ECRP). The Radiological Level Index, Iγ for the soil ranges between 0.12 to 1.18. However, one of the soils surrounding four angles bean has a Radiological Level Index, Iγ of 1.18 higher than the recommended value of 1. For the vegetable sample, it is found that the absorbed dose rate, DN is ranged between 1.75 to 16.94 nGy h-1. The value of Annual Ingestion Dose (Aeff) ranges from 2.54 μSv y-1 to 22.89 μSv y-1. The range of Annual Effective Dose Equivalent (AEDE) is between 2.15 μSv y-1 to 20.78 μSv y-1. The value of Excess Life-time Cancer Risk (ELCR) ranges between 0.80 × 10-5 to 7.79 × 10-5. The Annual Ingestion Dose, Annual Effective Dose Equivalent and ELCR are found to be lower than the value recommended by UNSCEAR. Results showed that the activity concentration of 137Cs in the soil samples ranged between 0.34 ± 0.09 to 3.21 ± 0.17 Bqkg-1. Dose rate computed from the corresponding value of activity concentration ranged from 0.01 to 0.10 nGyh-1. The annual effective dose rate ranged between 1.25 to 11.8 μSv y-1. The values of ELCR ranged between 0.47 × 10-5 to 4.45 × 10-5 which is lower than the safety limit of 0.29 × 10−3. The results of this investigation show that the assessed values are below the UNCSEAR and ICRP recommended values and do not present radiological hazards to the general population.

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