Natural background radiation in the Kinta District, Perak Malaysia

Measurement of natural background radiation levels in the Kinta District was carried out between 2003 and 2005. Gamma dose rates were measured from 1007 locations using a portable gamma-ray survey meter, Model 19 Micro R meter manufactured by Ludlum. The measured dose rates ranged from 39 to 1039 nGy h-1 and have a mean dose rate of 222 ± 191 nGy h-1 (1.36 mSv y-1). Two small areas of hot spots around Kampung Sungai Durian with dose rates of 1039 nGy h-1 were found. This is the highest dose rate recorded in Perak to date. A total of 128 soil samples collected were analyzed for the activities of the naturally occurring radionuclides, gross alpha and gross beta activities. The activity concentrations of 238U, 232Th and 40K were analyzed by using a HPGe detector. The ranges are 12 – 426 Bq kg-1 for 238U, 19 – 1377 Bq kg-1 for 232Th and from less than 19 – 2204 Bq kg-1 for 40K. Based on the radioactivity levels determined, the gamma absorbed dose rates in air at 1 meter above the ground were calculated using the procedure applied by UNSCEAR 2000. The total calculated dose rates and measured dose rates have shown good correlation coefficient of 0.94. The calculated Radium Equivalent Activity (Raeq) range from 0.14 to 6.01 mSv y-1. The gross alpha activity of the soil samples range from 15 to 9634 Bq kg-1 with a mean value of 1558 ± 121 Bq kg-1. The gross beta activity range from 142 to 6173 Bq kg-1 with a mean value of 1112 ± 32 Bq kg-1. The mean population weighted dose rate for the Kinta district is 1.2 mSv y-1. Gamma isodose map for the Kinta District was plotted. The isodose map is the most recent and can be used as a reference

Pembinaan dan pengujian kebok optik pantulan penuh sinar-x

Optical box for the TXRF system was developed. Alignment for the total reflection point of the x-ray beams has been done manually. Sampel targetted at the reflection point has been tested. Sampels with difference concentrations have been used. Linearity of the system was good. The detection power of the system is better for quarts compared to perspects

Natural gamma background radiation dose rate and its relationship with geological background in the Kinta District, Perak, Malaysia

A survey of natural gamma background radiation (NGBR) levels in the Kinta District was carried out for three years between 2003 and 2005. Dose rates were measured from 1007 locations by using a portable gamma-ray survey meter manufactured by Ludlum,Model 19 MicroR Meter. The measured dose rates ranged from 39 to 1039 nGy h-1. It has a mean dose rate of 222 ± 191 nGy h-1. Small areas of hot spot around Kampung Sungai Durian with dose rates of 1039 ± 104 nGy h-1. This is the highest recorded in Perak to date. Geological type G5 is Jurassic – Triassic, the rock type is mainly granites. It exhibits the highest mean dose rate of 432 ± 259 nGy h-1. The dose rates range from 91 to 1039 nGy h-1. The lowest recorded was on sandstones, the dose rate is 39 nGy h-1. The mean population weighted dose rate for the Kinta District is 1.12 mSv y-1. Gamma isodose map for the Kinta District was plotted

Concentration of uranium and thorium in the product and by-productof amang and ilmenite tailings process

Amang are by-products obtained when tailings are processed into concentrated ores and other economical products such as monazite, (Ce, La, Th)PO4; zircon, ZrSiO4; ilmenite, FeTiO3; struverit; and xenotime, YPO4. Its could be extracted from amang for further usage. Tailings from these ores may have a significant potential to cause elevated radiation exposures. This project was carried out to measure the concentration of uranium and thorium in the waste and products produced after the processing of the amang and ilmenite ore. The concentration of uranium and thorium was determined using gamma ray spectrometer with HPGe detector. The concentration of uranium was determined by measuring the intensity of gamma ray emitted from its daughter nuclei 214Pb at 352 keV and 214Bi at 609 keV while the concentration of thorium was determined by measuring the intensity of gamma rays emitted from its daughter nuclei 228Ac at 911 keV and 208Tl at 583 keV. The concentration of uranium and thorium in ppm obtained in this study are as follows: raw amang (83 -383) and (174 - 1566); ilmenite (149 - 290) and (301- 575); monazite (2303 - 4070) and (9641 – 60061); zircon (963 - 1192) and (353 - 583) and waste (22 - 98) and (44 - 223) respectively. Rutile and iron oxide was obtained from ilmenite. The concentration of uranium and thorium in rutile was 50 and 72 ppm and from iron oxide was 336 and 379 ppm respectively. These values are considered high compare to normal sand and could pose danger to the surrounding

Comparison of activity concentration of 238U, 232Th and 40K in different layers of subsurface structures in DeiDei and Kubwa, Abuja, North Central Nigeria

The study of activity concentration of 232Th, 238U and 40K of rock samples from site one (S1L1–S1L11, 70 m) and site two (S2L1–S2L9, 60 m) boreholes in Dei-Dei and Kubwa was presented and the first time in the region to be compared. Activity concentrations were analysed using a high resolution co-axial HPGe gamma ray spectrometer system. The activity concentration ranges in site one borehole were from 45±1 to 98±6 Bq kg−1 for 232Th, from 18±2 to 37±4 Bq kg−1 for 238U and from 254 ±32 Bq kg−1 to 1195 ±151 Bq kg−1 for 40K. The activity concentration ranges in site two borehole were from 32±3 to 84±7 Bq kg−1 for 232Th, from 15±2 to 52±5 Bq kg−1 for 238U and from 119±15 to 705±94 for 40K Bq kg−1. Significantly higher concentration of 232Th and 238U occurs in samples collected from S1L7, S1L11 and S2L1 layers. These zones experienced granitic intrusions produced by denudation and tectonism. 40K in rock samples of S1L4 and S2L4 activity concentrations is close; it could be that biotite granitic intrusion that is inferred as the formation in that layer reflects the same activity of potassium in rock's radioactivity measurement. The area requires further investigation of soil geochemistry and activity concentration of radionuclides in groundwater

Radioactivity level and toxic elemental concentration in groundwater at Dei-Dei and Kubwa areas of Abuja, north-central Nigeria

The activity concentrations of uranium and toxic elements in Dei-Dei borehole, Kubwa borehole, Water Board and hand-dug well water samples in Abuja area were measured using inductively coupled plasma mass spectrometry (ICP-MS) system. The results obtained were used to calculate human radiological risk over lifetime consumption by the inhabitants in the area. The activity concentrations of 238U in all the water supplies for drinking ranges from 0.849mBqL-1 to 2.699mBqL-1 with the highest value of 2.699mBqL-1 noted at Dei-Dei borehole whereas the lowest value of 0.849mBqL-1 was noted in Kubwa borehole. The highest annual effective dose from natural 238U in all the water samples was found in Dei-Dei borehole with a value of 8.9×10-5mSvy-1 whereas the lowest value was noted in Kubwa borehole with a value of 2.8×10-5mSvy-1. The radiological risks for cancer mortality were found distinctly low, with the highest value of 1.01×10-7 reported at Dei-Dei borehole compared to Kubwa borehole with a value of 3.01×10-8. The cancer morbidity risk was noted higher in Dei-Dei borehole with a value of 1.55×10-7 whereas lower value of 4.88×10-9 was reported in Kubwa borehole. The chemical toxicity risk of 238U in drinking water over a lifetime consumption has a value of 0.006µgkg-1day-1 in Dei-Dei borehole whereas lower value of 0.002µgkg-1day-1 was found in Kubwa borehole. Measured lead (Pb) and chromium (Cr) concentrations reported higher in Water Board compared to Dei-Dei and Kubwa borehole samples. Significantly, this study inferred that the 238U concentrations originate from granitic strata of the tectonic events in the area; thus, there was a trend of diffusion towards north to south and re-deposition towards Dei-Dei area

Radiological monitoring: terrestrial natural radionuclides in Kinta District, Perak, Malaysia

Natural background gamma radiation and radioactivity concentrations were investigated from 2003 to 2005 in Kinta District, Perak, Malaysia. Sample locations were distant from any 'amang' processing plants. The external gamma dose rates ranged from 39 to 1039 nGy h-1. The mean external gamma dose rate was 222 ± 191 nGy h-1. Small areas of relatively enhanced activity were located having external gamma dose rates of up to 1039 ± 104 nGy h-1. The activity concentrations of 238U, 232Th and 40K were analyzed by using a high-resolution co-axial HPGe detector system. The activity concentration ranges were 12-426 Bq kg-1 for 238U, 19-1377 Bq kg-1 for 232Th and <19-2204 Bq kg-1 for 40 K. Based on the radioactivity levels determined, the gamma-absorbed dose rates in air at 1 m above the ground were calculated. The calculated dose rates and measured dose rates had a good correlation coefficient, R of 0.94. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the gamma-absorbed dose rate and the mean population weighted dose rate were calculated. An isodose map for the Kinta District was also produced