Sains Malaysiana 47(4)(2018): 797-803

http://dx.doi.org/10.17576/jsm-2018-4704-19

Determination of Uranium Internal Dose Exposure through Soil Digestion Using

RDRC and URODC Software

(Penentuan Dos Dedahan Dalaman Uranium Melalui Penghadaman Tanih Menggunakan

Perisian RDRC dan URODC)

MOHD IZWAN ABDUL ADZIZ, NOR AMIRA AMALINA MOHD BADRI & KHOO KOK SIONG*

Pusat Pengajian Fizik Gunaan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

Diserahkan: 14 September 2017/Diterima: 25 Oktober 2017

ABSTRACT

This study was conducted to determine the dose of internal exposure through ingestion of soil in the vicinity of the repository facility in Bukit Kledang, Ipoh, Perak. Data from this study can assess the risk of radiation exposure to the health of local population, specifically blood, liver and bone cancers. Activities of radionuclide ²³⁸U in MG and M10 in the gastric phase are 1.118 ± 0.062 and 1.232 ± 0.073 Bq/kg, while the respective activities in the gastrointestinal phase are 0.553 ± 0.051 and 0.905 ± 0.082 Bq/kg. Samples of M10 recorded the highest reading of internal exposure in both phases. Digestion of 2 g soil from M10 samples on gastric phase generated the annual effective dose of 3.168 μSv/year with an assessment of cancer risk by 0.001% within 70 years to public. Organ dose for blood, liver and bone were 0.59, 11.60 and 65.95 μSv, respectively. Analysis of organ doses based on the concentration of ²³⁸U found that M10 has higher dose compared to MG. Risk assessment predicted for 70 years after the ingestion of the soil for blood cancer was 0.003% and liver cancer was 0.004% while the highest cancer risk was for bone cancer with 0.023%. Although the concentration of specific activity of  ²³⁸U identified is low, it is shown that the internal dose exposure as a result of digestion of radionuclides are below the standard and can be considered as safe for public.

Keywords: Cancer risk; internal dose exposure; repository facility; soil sample; ²³⁸U

ABSTRAK

Kajian ini dijalankan untuk menentukan dos dedahan dalaman melalui penghadaman tanih di kawasan sekitar fasiliti repositori di Bukit Kledang, Ipoh, Perak. Data daripada kajian ini dapat menilai risiko dedahan sinaran terhadap kesihatan penduduk setempat khususnya penyakit kanser darah, hati dan tulang. Aktiviti spesifik radionuklid ²³⁸U di MG dan M10 pada fasa gastrik masing-masing adalah 1.118 ± 0.062 dan 1.232 ± 0.073 Bq/kg, manakala nilai aktiviti spesifik tanih di MG dan M10 pada fasa gastrousus pula masing-masing adalah 0.553 ± 0.051 dan 0.905 ± 0.082 Bq/ kg. Sampel M10 merekodkan bacaan dos dedahan dalaman tertinggi berbanding dengan sampel MG pada kedua-dua fasa. Penghadaman 2 g tanih pada fasa gastrik sampel M10, merekodkan dos berkesan tahunan sebanyak 3.168 µSv/ tahun dengan penilaian risiko kanser sebanyak 0.001% dalam jangka masa 70 tahun untuk orang awam. Dos organ bagi darah, hati dan tulang masing-masing adalah sebanyak 0.59, 11.60 dan 65.95 µSv. Dos organ ini juga dianalisis berdasarkan kepekatan ²³⁸U. Didapati bahawa dos ini lebih tinggi untuk M10 berbanding MG. Penilaian risiko dalam jangka masa 70 tahun bagi kanser darah adalah 0.003%, kanser hati sebanyak 0.004% manakala paling tinggi untuk mendapat kanser tulang iaitu sebanyak 0.023%. Lantaran nilai kepekatan aktiviti ²³⁸U yang dikenal pasti adalah rendah maka ia membuktikan bahawa dedahan sinaran dan dos dedahan dalaman sinaran akibat penghadaman radionuklid ini adalah di bawah piawai yang ditetapkan.

Kata kunci: Dos dedahan dalaman; fasiliti repositori; risiko kanser; sampel tanih; ²³⁸U

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*Pengarang untuk surat-menyurat; email: khookoksiong@gmail.com