Malaysian Journal of Analytical Sciences Vol 19 No 2 (2015): 300 – 308

 

 

 

PENENTUAN AKTIVITI RADIONUKLID SERTA IMPAK RADIOLOGI MELALUI PENGAMBILAN SUSU TEPUNG, TEPUNG GANDUM, TEH DAN KOPI

 

(Determination of Radionuclide Activity and Radiological Impact from the Intake of Milk, Wheat Flour, Tea and Coffee)

 

Nik Nadia Hazwani Nek Kamal¹*, Norafatin Khalid², Che Nor Aniza Che Zainul Bahri²,  Amran Ab Majid²

 

¹Program Pengimejan Diagnostik,

Fakulti Perubatan & Sains Kesihatan,

Universiti Sultan Zainal Abidin Kampus Gong Badak, 21300 Terengganu

²Program Sains Nuklear, Pusat Pengajian Fizik Gunaan,

Fakulti Sains dan Teknologi,

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

 

*Corresponding author: niknadiahazwani@gmail.com

 

 

Received: 23 January 2014; Accepted: 20 November 2014

 

 

Abstrak

Pengambilan makanan yang mengandungi radionuklid boleh menyumbang kepada dos dalaman. Kajian berkaitan kandungan radionuklid dalam beberapa jenis makanan perlu dilakukan untuk melihat kesan yang bakal diterima oleh manusia. Objektif penyelidikan ini dijalankan adalah i) menentukan kepekatan aktiviti di dalam susu tepung, teh, tepung gandum dan kopi, ii) mengira dos dedahan tahunan melalui produk makanan tersebut dan risiko kanser sepanjang hayat rakyat Malaysia. Kepekatan aktivti radionuklid ²²⁶Ra, ²³⁸U, ²³²Th dan ⁴⁰K ditentukan menggunakan kaedah spektrometri sinar gama. Hasil kajian mendapati purata kepekatan aktiviti dalam susu tepung, teh, tepung gandum dan kopi masing-masing adalah 1.6 ± 0.8, 3.3 ± 0.4, 1.2 ± 0.2, 2.1 ± 0.7 Bq kg^-1 bagi ²²⁶Ra, 1.6 ± 0.2, 10.7 ± 3.3, 2.1 ± 0.6 dan 1.8 ± 0.2 Bq kg^-1 bagi ²³⁸U, 1.8 ± 0.5, 9.5 ± 2.2, 1.9 ± 0.1, 2.2 ± 0.3 Bq kg^-1 bagi ²³²Th dan 190.2 ± 49.6, 395.4 ± 11.9, 57.4 ± 28.5, 429.4 ± 305.5 Bq kg^-1 bagi ⁴⁰K. Dos dedahan dalaman tahunan bagi kanak-kanak melalui pengambilan susu tepung masing-masing adalah 63.5 µSv bagi ²²⁶Ra, 32.2 µSv bagi ²³²Th, 2.8 µSv bagi ²³⁸U dan 326.5 µSv bagi ⁴⁰K. Manakala, dos dedahan dalaman tahunan bagi orang dewasa melalui pengambilan tepung gandum, teh dan kopi masing-masing adalah 13.7 µSv bagi ²²⁶Ra, 18.0 µSv bagi ²³²Th, 5.1 µSv tahun^-1 bagi ²³⁸U dan 24.2 µSv tahun^-1  bagi ⁴⁰K. Dos dedahan kesemua radionuklid adalah 425 µSv tahun^-1 bagi kanak-kanak dan 61.0 µSv tahun^-1 bagi orang dewasa. Nilai ini memberikan faktor risiko kanser sebanyak 1.8 x 10^-3 bagi kanak-kanak dan 1.7 x 10^-4 bagi orang dewasa. Ia bermaksud kebarangkalian peningkatan risiko kanser sepanjang hayat sebanyak 0.18 % bagi kanak-kanak (18 orang dalam 10 000) dan 0.017 % bagi orang dewasa (1.7 orang dalam 10 000). Nilai-nilai ini adalah lebih rendah berbanding faktor risiko kanser ICRP bagi orang awam iaitu 2.5 x 10^-3 dan jumlah risiko daripada semua sumber sinaran berdasarkan purata nilai dos tahunan dunia 2.4 mSv tahun^-1 iaitu 6 x 10^-3. Oleh itu, kajian ini menunjukkan bahawa pengambilan susu tepung, tepung gandum, teh dan kopi tidak memberikan bahaya kesihatan yang signifikan dan dianggap selamat secara radiologi untuk diambil oleh manusia.

 

Kata kunci: radionuklid, kepekatan aktiviti, dos dedahan dalaman, risiko kanser, kanak-kanak, orang dewasa

 

Abstract

Consumption of food containing radionuclides may contribute to internal dose. Studies on radionuclide content in several types of food should be done to determine effects to human. The objectives of this research are to i) determine the activity concentration in milk powder, tea, flour and coffee samples, ii) to calculate the annual exposure dose in food products and iii) to determine the lifetime cancer risk amongst Malaysians. The concentrations of ²²⁶Ra, ²³⁸U, ²³²Th and ⁴⁰K were determined using gamma ray spectrometry. The study found that the mean activity concentration in milk powder, tea, flour and coffee are 1.6 ± 0.8 , 3.3 ± 0.4 , 1.2 ± 0.2, 2.1 ± 0.7 Bq kg^-1 for ²²⁶Ra , 1.6 ± 0.2, 10.7 ± 3.3 , 2.1 ± 0.6 and 1.8 ± 0.2 Bq kg^-1 for ²³⁸U , 1.8 ± 0.5, 9.5 ± 2.2 , 1.9 ± 0.1 , 2.2 ± 0.3 Bq kg^-1 for ²³²Th and 190.2 ± 49.6 , 395.4 ± 11.9 , 57.4 ± 28.5 , 429.4 ± 305.5 Bq kg^-1 for ⁴⁰K, respectively. The annual internal exposure dose for children through consumption of milk powder are 63.5 μSv for ²²⁶Ra, 32.2 μSv for ²³²Th, 2.8 μSv for ²³⁸U and 326.5 μSv for the ⁴⁰K, respectively. Whereas, the annual internal exposure dose for adults through consumption of wheat flour, tea and coffee are 13.7 μSv for ²²⁶Ra , 18.0 μSv for ²³²Th , 5.1 μSv year^-1  for ²³⁸U and 24.2 μSv year^-1  for ⁴⁰K, respectively. All radionuclide exposure doses are 425 μSv year^-1 for children and 61.0 μSv year^-1 for adults. This value provides a risk factor of 1.8 x 10^-3 cancer for children and 1.7 x 10^-4 for adults. It means that the probability of lifetime cancer risk increment of 0.18 % for children (18 people in 10 000) and 0.017 % for adults (1.7 people in 10 000). These values ​​are lower than the ICRP cancer risk factors for the public of 2.5 x 10^-3 and the total risk from all sources of radiation dose based on the global annual dose of 2.4 mSv year^-1 which is 6 x 10^-3. The study revealed that the intake of milk powder, flour, tea and coffee do not contribute a significant health hazard and is considered radiological safe to be taken by humans.

 

Keywords: radionuclides, specific activity, annual exposure dose, cancer risk, children, adult

 

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