Sains Malaysiana 37(2): 115-122(2008)

Variasi Profil ²¹⁰Po dan ²¹⁰Pb dalam Teras Sedimen

di Pesisir Pantai Perairan Sarawak

(Variation of ²¹⁰Po and ²¹⁰Pb Profile in the Sediment

Core of Sarawak Coastal Waters)

Zal U’yun Wan Mahmood & Che Abd Rahim Mohamed

Pusat Pengajian Sains Sekitaran & Sumber Alam

Fakulti Sains & Teknologi, Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E. Malaysia

Zaharudin Ahmad & Abdul Kadir Ishak

Agensi Nuklear Malaysia, Kompleks MINT, Bangi

43000 Kajang, Selangor D.E. Malaysia

Diserahkan: 16 Ogos 2007 / Diterima: 4 Oktober 2007

ABSTRAK

Kajian ini dijalankan untuk  melihat variasi taburan ²¹⁰Po dan ²¹⁰Pb melalui profil menegak aktivitinya, serta nisbah aktiviti ²¹⁰Po/²¹⁰Pb  di dalam teras sedimen yang diambil di beberapa stesen persampelan  pesisir pantai perairan Sarawak.  Didapati profil taburan radionuklid tersebut dalam teras sedimen adalah berubah-ubah mengikut lokasi persampelan dan telah dibuktikan melalui analisis ANOVA yang menunjukkan bahawa terdapat perbezaan bererti pada 95% aras keyakinan bagi aktiviti ²¹⁰Po (p = 0.000), ²¹⁰Pb (p = 0.035) dan ²¹⁰Po/²¹⁰Pb (p = 0.000) di semua lokasi kajian.  Secara umumnya,  aktiviti  ²¹⁰Po dan ²¹⁰Pb  yang diukur masing-masing dalam  julat 337 ke 2460 Bq/kg, 11 ke 84 Bq/kg di SR 01; 224 ke 2008 Bq/kg, 6 ke 80 Bq/kg di SR 02; 119 ke 1595 Bq/kg, 6 ke 84 Bq/kg di SR 03; 241 ke 2294 Bq/kg, 5 ke 82 Bq/kg di SR 04 dan 175 ke 1340 Bq/kg, 4 ke 44 Bq/kg di SR 05.  Merujuk kepada julat tersebut, didapati aktiviti ²¹⁰Po adalah lebih tinggi daripada aktiviti ²¹⁰Pb dengan purata nisbah ²¹⁰Po/²¹⁰Pb di semua stesen adalah melebihi satu, iaitu dalam julat 20 ke 35.  Variasi profil taburan radionuklid tersebut dipercayai dipengaruhi oleh beberapa faktor sekitaran dan telah dibuktikan terdapat korelasi yang kuat di antara taburan radionuklid dengan komposisi sedimen jenis kelodak (²¹⁰Po:r = 0.701 dan ²¹⁰Pb: r = 0.648), kedalaman air (²¹⁰Po: r = -0.647) dan jarak stesen dari daratan (²¹⁰Po: r = 0.746 dan  ²¹⁰Pb: r = 0.975).  Oleh itu, dapat disimpulkan bahawa faktor-faktor tersebut merupakan penyumbang utama ke atas perubahan yang berlaku kepada taburan ²¹⁰Po dan ²¹⁰Pb.

Kata kunci:  ²¹⁰Po; ²¹⁰Pb; teras sedimen; perairan Sarawak

ABSTRACT 

This study was performed to observe the variation in the distribution of ²¹⁰Po and ²¹⁰Pb through their activity vertical profile and ²¹⁰Po/²¹⁰Pb activity ratio in the sediment cores that ware taken at some sampling stations in the Sarawak coastal waters.  It was found that the distribution profile of those radionuclide in the sediment cores varied depending on the sampling location and ANOVA analysis shows significant difference at 95% confidence level for activities of ²¹⁰Po (p = 0.000), ²¹⁰Pb (p = 0.035) and ²¹⁰Po/²¹⁰Pb (p = 0.000) at  all study locations.  Generally, the measured activity of ²¹⁰Po and ²¹⁰Pb ranged from 337 to 2460 Bq/kg, 11 to 84 Bq/kg at SR 01; 224 to 2008 Bq/kg, 6 to 80 Bq/kg at SR 02; 119 to 1595 Bq/kg, 6 to 84 Bq/kg at SR 03; 241 to 2294 Bq/kg, 5 to 82 Bq/kg at SR 04 and 175 to 1340 Bq/kg, 4 to 44 Bq/kg at SR 05, respectively. In those range it was found that ²¹⁰Po activities were higher than ²¹⁰Pb with  average of ²¹⁰Po/²¹⁰Pb ratios at all stations were from  20 to 35.  The variation in the distribution profile for the radionuclides are believed to be influenced by some environmental factors and have strong correlation between the radionuclide distribution and the sediment composition of silt (²¹⁰Po: r = 0.701 and ²¹⁰Pb: r = 0.648), water depth (²¹⁰Po: r = -0.647) and the distance from the sampling station to the main land (²¹⁰Po: r = 0.746 and ²¹⁰Pb: r = 0.975).  Those factors are a major contributions on the variation of ²¹⁰Po and ²¹⁰Pb in the samples.

Keywords:  ²¹⁰Po; ²¹⁰Pb; sediment core; coastal waters of Sarawak

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