Measurement of natural radioactivity level in surface sediment in southern Kuala Selangor coastal area

Abstract

Kuala Selangor is located in Sungai Selangor estuary in the west coast of Peninsular Malaysia. Kuala Selangor coastal area is susceptible to pollution load as a lot of industrial and human activities are located in the west coast of Peninsular Malaysia and along Sungai Selangor. Surface sediment was taken from 14 points at two locations in southern Kuala Selangor that are in ‘Pantai Remis’ and ‘Pantai Jeram’. This study focused on radioactivity level of naturally occurring radionuclide (mainly 226Ra, 228Ra and 40K) in surface sediment using gamma-ray spectrometry with a high-purity germanium (HPGe) detector. For 40K, the presence of this was measured directly via its 1460 keV energy peak. For 226Ra (of the 238U) and 228Ra (of the 232Th) the γ-ray lines 609.3 keV (214Bi) and 911.1 keV (228Ac) were used. The concentration of 226Ra, 228Ra and 40K in samples obtained from Pantai Remis coastal area ranged between 42.9±1.4-60.0±1.6 (mean 47.6±1.5) Bq/kg, 61.9±2.8-79.3±2.9 (mean 69.5±2.7) Bq/kg and 324.5±10.6-455.8±13.2 (mean 422.2±12.2) Bq/kg, respectively. Meanwhile, the concentration of 226Ra, 228Ra and 40K in samples obtained from Pantai Jeram coastal area ranged between 45.1±1.6-50.4±1.5 (mean 47.2±1.6) Bq/kg, 62.5±2.8-75.9±3.0 (mean 69.2±2.9) Bq/kg and 338.7±10.7-490.6±14.0 (mean 428.2±12.4) Bq/kg, respectively. The mean external hazard index due to these radionuclides is 0.484 for ‘Pantai Remis’ and ‘Pantai Jeram’ (less than unity). Thus, it is expected that no radiation hazard attributed to the radiation from the study radionuclides will be experience by people in the areas.