Natural Radioactivity In Domestic Water Sources In Northern Peninsular Malaysia
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Date
2012-03
Authors
Muhammad, Bashir Gide
Journal Title
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Publisher
Universiti Sains Malaysia
Abstract
Bioaccumulation of dissolved radioactive materials through drinking water is considered an important pathway for long-term health concerns. Thus, the World Health Organization (WHO) guidelines for drinking water radiological quality were adopted to screen the adequately utilized surface water resources in northern peninsular Malaysia for natural radioactivity. The sampling locations were 12, 26, 16 and 19 from the states of Penang, Perlis, Kedah and Perak, respectively. Firstly, gross alpha and gross beta activity concentrations were measured in the raw and subsequently the treated domestic water supply sources using International Standard Organisation (ISO) proceedures. An eight channel gas flow proportional counting system (EURYSIS-IN20) was employed in this analysis. The gross alpha and beta activity concentrations in the raw water were found to range from 90 ± 6.30 Bq m-3 to 490 ± 21.20 Bq m-3 and 370 ± 3.00 Bq m-3 to 1890 ± 26.00 Bq m-3, respectively. The gross alpha values fall below the ICRP and WHO recommended MCL of 500 Bq m-3 while the gross beta values in some samples exceeds the MCL value of 1000 Bq m-3(similarly adopted by the Malaysian National Drinking Water Quality Standards). The high beta activity concentration values in some areas prompted the need for further screening. In this regard, gamma spectroscopic analysis was employed to analyze the natural radionuclides (U-238, Th-232, K-40 and Ra-226) in the water and soil samples from the domestic water sources. Subsequently, the age dependent committed effective doses due to direct
ingestion of these nuclides were estimated using the Dose Conversion Factors (DCF) provided by UNSCEAR. The results indicated the mean committed effective doses to be 0.112 mSv, 0.104 mSv and 0.100 mSv for infants, children and adults, respectively.
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Keywords
Natural radioactivity in domestic water sources , in northern peninsular Malaysia