Sains Malaysiana 33(2): 137-145 (2004)                                                                                      Sains Bumi /

Earth Science

Perubahan Kepekatan Aktiviti Ra-226 dan Ra-228 di Sepanjang

Sungai Langat dan Sungai Semenyih, Selangor

(Variation in Concentration of Ra-226 and Ra-228 activities along

Langat and Semenyih River, Selangor)

Phuah Chai Shia, Che Abd Rahim Mohamed

Pusat Pengajian Sains Sekitaran dan Sumber Alam

Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E.

Zaharudin Ahmad

Malaysian Institute for Nuclear Technology Research (MINT)

43650 UKM Bangi, Selangor D.E.

ABSTRAK

Penentuan kepekatan aktiviti Ra-226 dan Ra-228 dalam sampel air dan sedimen dilakukan masing-masing dengan Pembilang Sintilasi Cecair (LSC) dan Spektrometri Gamma Germanium Lampau Tulen (HPGe). Kepekatan aktiviti Ra-226 dalam sampel sedimen adalah berjulat dari 18.93 Bg/kg hingga 236.06 Bq/kg dan kepekatan aktiviti Ra-228 berjulat dari 12.59 Bg/kg hingga 410.60 Bq/kg. Kepekatan aktiviti Ra-226 dalam sampel air yang diperolehi pula berjulat dari 0.064 Bg/L hingga 0.199 Bq/L. Ini menunjukkan taburan Ra-228 dan Ra-226 di kawasan kajian adalah berubah mengikut lokasi kajian dan berkemungkinan dipengaruhi oleh sifat kandungan bahan terampai.

ABSTRACT

Concentration of Ra-226 and Ra-228 activities in water and sediment samples were measured using the Liquid Scintillation Counter (LSC) and High Purity Germanium Gamma Spectrometry (HPGe). respectively. Concentrations of Ra-226 activity in sediment samples range from 18.93 Bg/ kg to 236.06 Bq/kg and for Ra-228 activity range from 12.59 Bg/kg to 410.60 Bq/kg. Meanwhile, concentrations of Ra-226 activity obtained in water samples range from 0.064 Bg/L to 0.199 Bq/L. These data indicate, that the distribution of Ra-228 and Ra-226 in the study area were varied from one sampling stations to another and is probably related to the contents of suspended particles.

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