Assessment of natural radionuclides in rivers of Pahang State Malaysia

Investigations were conducted to determine the radionuclide concentration levels in the major rivers in Pahang state, Malaysia. Since the rivers are the main sources for water supply in the state, it is important to measure natural radionuclide concentrations in the rivers. Seventeen water samples were collected from major rivers in Pahang state. The concentration of uranium, thorium and potassium were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The samples were found to contain permissible levels of radionuclides with a mean activity concentrations of uranium, thorium and potassium found to be 8.49 ± 0.34 mBq L-1, 1.74 ± 0.27 mBq L-1and 77.85 ± 0.96 mBq L-1respectively. The ratio between thorium and uranium concentration is found to be 3:4 due to the higher solubility of uranium than thorium in water. Radionuclide concentrations obtained were compared with the terrestrial gamma radiation dose rate measured around the area. A good relation was observed between uranium and thorium concentrations with gamma dose rate obtained around the area while no relation was found between the potassium concentrations with gamma dose rate. Significance of the results obtained is discussed

Radiological mapping of Kelantan, Malaysia, using terrestrial radiation dose rate

Measurements of the environmental terrestrial gamma radiation dose rate (TGRD) in each district of Kelantan state, Malaysia, were carried out using a portable hand-held radiation survey meter and global positioning system. The measurements were done based on geology and soil types of the area. The mean TGRD was found to be 209 nGy h–1. Few areas of relatively enhanced activity were observed in Pasir Mas, Tanah Merah and Jeli districts, which have a mean TGRD between 300 and 500 nGy h–1. An isodose map of the area was produced using ArcGIS software version 9.3

Natural radioactivity measurements in Pahang State, Malaysia

This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176 ± 5 nGy h-1. Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides226Ra,232Th and40K are 110 ± 3, 151 ± 5 and 542 ± 51 Bq kg-1, respectively.226Ra and232Th concentrations were found to be three times the world average, while that of40K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for226Ra (215 ± 6 Bq kg-1),232Th (384 ± 12 Bq kg-1) and40K (1564 ± 153 Bq kg-1). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg-1 and the unity value, respectively

The potential health hazards of chronic exposure to low-dose natural radioactivity in Terengganu, Malaysia

Measurement of terrestrial gamma radiation dose (TGRD) rate and activity concentrations of naturally occurring radionuclides in environmental media such as soil and air play an important role in the setting national average permissible doses to members of public. Malaysia is planning to add nuclear energy to its national electricity grid; hence the knowledge of the levels of exposure to natural background radioactivity is important for policies and law making with regards to radiological protection of both human and the environment. The aim of this work was to measure the variation of background radiation with respect to geological formations of Terengganu (Malaysia) and assess the potential health hazards that are associated with the chronic exposure to natural radiation in the area. Ludlum 19 micro survey meters with NaI[Tl] detectors and HPGe gamma ray spectrometer were used for in situ TGRD and laboratory analysis, respectively. The measured TGRD rates ranged from 35 to 340 nGy h−1 with mean value of 150 nGy h−1 and the annual effective dose to population was 0.92 mSv year−1. The mean (range) activity concentrations of 226Ra, 232Th, and 40K in the soil samples were 79 ± 3 (20 ± 1–151 ± 5) Bq kg−1; 84 ± 3 (8 ± 1–182 ± 6) Bq kg−1; and 545 ± 55 (47 ± 5–1056 ± 107) Bq kg−1, respectively. Upon comparing these values with the world averages for specific activities of 226Ra, 232Th and 40K (i.e. 33, 36 and 474 Bq kg−1 for 226Ra, 232Th and 40K respectively), It is revealed that the mean activity concentrations of 226Ra and 232Th in the soil of Terengganu are higher than the world averages by a factor of two. The mean activity concentration of 40K in the soil of Terengganu is ~15 % higher than the world average. Acid intrusive geological formation (due to the granite composition from igneous rocks), which is the most dominant in the state was found to contained higher mean TGRD values as well as 226Ra and 232Th concentration this was consistent with some previous studies