B.A. Almayahi

Radiation hazard indices of soil and water samples in Northern Malaysian Peninsula.

The radioactivity quantity and quality were determined in soil and water samples in Northern Malaysian Peninsula (NMP) using HPGe spectroscopy and GR-135 spectrometer. The (226)Ra, (232)Th and (40)K concentrations in soil samples are 57±2, 68±4 and 427±17 Bq kg(-1), respectively, whereas in water samples were found to be 2.86±0.79, 3.78±1.73 and 152±12 Bq l(-1), respectively. These concentrations are within those reported from literature in other countries in the world. The radiological hazard indices of the samples were also calculated. The mean values obtained from soil samples are 186 Bq kg(-1), 88 nGy h(-1), 108 μSv y(-1), 0.50 and 0.65 for Radium Equivalent Activity (Ra(eq)), Absorbed Dose Rates (D(R)), Annual Effective Dose Rates (ED), External Hazard Index (H(ex)) and Internal Hazard Index (H(in)) respectively, whereas, for water samples were found to be 20, 10, 13, 0.05 and 0.06, respectively. All the health hazard indices are well below their recommended limits, except in two soil sampling sites which were found to be (*)025 (1.1 H(ex)) and (*)026 (1.1 H(ex), 1.6 H(in)). The calculated and the measured gamma dose rates had a good correlation coefficient, R=0.88. Moreover, the average value radon is 20 (in the range of 7-64) Bq m(-3), a positive correlation (R=0.81) was observed between the (222)Rn and (226)Ra concentrations in samples measured by the SNC continuous radon monitor (model 1029, Sun Nuclear Corporation) and HPGe detector, respectively. Some soils in this study with H(in) and H(ex)<1 are suitable for use in agriculture and as building materials. Also, in this study H(in) and H(ex)<1 for water samples, therefore, water after processing and filtration is safe and suitable for use in household and industrial purposes.

Radiobiological long-term accumulation of environmental alpha radioactivity in extracted human teeth and animal bones in Malaysia

In this study, the radiobiological analysis of natural alpha emitters in extracted human teeth and animal bones from Malaysia was estimated. The microdistributions of alpha particles in tooth and bone samples were measured using CR-39 alpha-particle track detectors. The lowest and highest alpha emission rates in teeth in the Kedah and Perak states were 0.0080 ± 0.0005 mBq cm(-2) and 0.061 ± 0.008 mBq cm(-2), whereas those of bones in the Perlis and Kedah states were 0.0140 ± 0.0001 mBq cm(-2) and 0.7700 ± 0.0282 mBq cm(-2), respectively. The average alpha emission rate in male teeth was 0.0209 ± 0.0008 mBq cm(-2), whereas that of female teeth was 0.0199 ± 0.0010 mBq cm(-2). The alpha emission rate in teeth is higher in smokers (0.0228 ± 0.0008 mBq cm(-2)) than in non-smokers (0.0179 ± 0.0008 mBq cm(-2)). Such difference was found statistically significant (p < 0.01).

Backscattering factor measurements of gamma rays of the different thickness of pure concrete

Abstract Backscattering peak is one of the main features of the pulse height spectrum from a gamma ray detector. This arises mainly from materials outside like source baking, photomultiplier tube housing, shielding etc. The effect of source backing on the relative importance of the backscattered peak for gamma ray using a NaI (Tl) scintillation detector is measured. Gamma energies in the range from 0.088MeV to 1.253MeV are used. Backscattering factor (Fb) measurements have been carried out (2>Fb≥1) of various pure concrete thickness from 2cm to 30cm.

Heavy Metals Concentration in Different Soil Samples in Najaf City, Iraq

In this study, the concentration of selected heavy metals including Co, Cd, Pb, and Cr in soils was assessed in Najaf city, Iraq using a Flame Atomic Absorption Spectrophotometer. Soil samples are collected from 12 different locations in Najaf city. The results revealed that the mean concentrations were in the order Pb > Co > Cr > Cd, in all the sites. The highest Pb (3.35 ppm) was found in sample S4 (Kufa river (surface)). All soil samples had lower values of total heavy metal concentrations than those recommended by the U.S. Environmental Protection Agency. Keywords— Heavy metals, soil, Najaf city, EPA