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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