Seasonal Variation of 210Po in Different Salinity: Case of Kuala Selangor River, West Coast Peninsular Malaysia

Che Abd Rahim Mohamed, Tan Chin Siang

Abstract: The relationship, input and output of 210Po has been investigated in the dissolved (0.4 ?m) samples collected from six stations in the Kuala Selangor River, where each station selected had a different salinity; ranging from the low salinity of surface layer water to the coastal oceanic water. The sampling discussed in this paper was undertaken on three dates; 22 May 2005 (during the dry season), 19 November 2005 (during the wet season) and 26 March 2006 (at the end of the wet season). Water samples were collected to measure the activities of 210Po after spontaneous deposition on a silver disc; with their activitiy determined through the use of an alpha spectrometry analyzer. The mean activity of total 210Po, which was found to alter according to the sampling dates, was noted as 57.83 ? 12.26 dpm L-1, 22.90 ? 3.21 dpm L-1 and 11.83 ? 4.13 dpm L-1 for the samples from 22 May 2005, 19 November 2005 and 26 March 2006, respectively. The highest concentration of activity of 210Po was obtained during the dry season, whilst the lowest activity found was during the end of the wet season. In March 2006, at the end of the wet season, the behavior of 210Po was found to behave in the manner of a conservative element. From the calculation model, approximately 82.14 % of the polonium input was found in the dissolve phase and around 144.94 % of the removed polonium remained in the particulate phase.

Keywords: radionuclide; polonium; coastal water; particulate; salinity