Zaini Hamzah

Experimental Determination of the HPGe Spectrometer Efficiency Calibration Curves for Various Sample Geometry for Gamma Energy from 50 keV to 2000 keV

Detection efficiency of a gamma‐ray spectrometry system is dependent upon among others, energy, sample and detector geometry, volume and density of the samples. In the present study the efficiency calibration curves of newly acquired (August 2008) HPGe gamma‐ray spectrometry system was carried out for four sample container geometries, namely Marinelli beaker, disc, cylindrical beaker and vial, normally used for activity determination of gamma‐ray from environmental samples. Calibration standards were prepared by using known amount of analytical grade uranium trioxide ore, homogenized in plain flour into the respective containers. The ore produces gamma‐rays of energy ranging from 53 keV to 1001 keV. Analytical grade potassium chloride were prepared to determine detection efficiency of 1460 keV gamma‐ray emitted by potassium isotope K‐40. Plots of detection efficiency against gamma‐ray energy for the four sample geometries were found to fit smoothly to a general form of e = AEa+BEb, where e is efficiency, ...

Determination of radon activity concentration in water using gamma spectrometry and liquid scintillation counter techniques

Naturally occurring radionuclides in water such as, 226Ra and 222Rn, emit gamma radiation through their decaying process which could reach to the human. The water samples were collected from, Kelantan, Perak and Pahang. At each sampling points, in situ measurement was done whereupon test were performed using GPS, LUDLUM rate meter, and HYDROLAB. Marinelli beakers and glass bottles were used to prepare the water samples. The samples were kept for a month to allow equilibrium between 226Ra, and 222Rn and its progenies to reach. The measurement was done using two different methods, and radon activities were ranged from (0.156–1.876 Bq/l).

An assessment of natural radionuclides in water of Langat River estuary, Selangor

An estuary is an area that has a free connection with the open sea and it is a dynamic semi-enclosed coastal bodies. Ex-mining, aquaculture and industrial areas in Selangor are the sources of pollutants discharged into the estuary water. Radionuclides are considered as pollutants to the estuary water. Gamma radiations emitted by natural radionuclides through their decaying process may give impact to human. The radiological effect of natural radionuclides which are 226Ra, 228Ra, 40K, 238U and 232Th, were explored by determining the respective activity concentrations in filtered water along the Langat estuary, Selangor. Meanwhile, in- situ water quality parameters such as temperature, dissolve oxygen (DO), salinity, total suspended solid (TSS), pH and turbidity were measured by using YSI portable multi probes meter. The activity concentration of 226Ra, 228Ra and 40K were determined by using gamma-ray spectrometry with high-purity germanium (HPGe) detector. The activity concentrations of 226Ra, 228Ra and 40K in samples are in the range of 0.17 - 0.67 Bq/L, 0.16 - 0.97 Bq/L and 1.22 - 5.57 Bq/L respectively. On the other hand, the concentrations of uranium-238 and thorium-232 were determined by using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The thorium concentrations are between 0.17 ppm to 0.28 ppm and uranium concentrations were 0.25 ppm to 0.31 ppm. The results show activity concentrations of radionuclides are slightly high near the river estuary. The Radium Equivalent, Absorbed Dose Rate, External Hazard Index, and Annual Effective Dose of 226Ra, 228Ra and 40K are also studied.An estuary is an area that has a free connection with the open sea and it is a dynamic semi-enclosed coastal bodies. Ex-mining, aquaculture and industrial areas in Selangor are the sources of pollutants discharged into the estuary water. Radionuclides are considered as pollutants to the estuary water. Gamma radiations emitted by natural radionuclides through their decaying process may give impact to human. The radiological effect of natural radionuclides which are 226Ra, 228Ra, 40K, 238U and 232Th, were explored by determining the respective activity concentrations in filtered water along the Langat estuary, Selangor. Meanwhile, in- situ water quality parameters such as temperature, dissolve oxygen (DO), salinity, total suspended solid (TSS), pH and turbidity were measured by using YSI portable multi probes meter. The activity concentration of 226Ra, 228Ra and 40K were determined by using gamma-ray spectrometry with high-purity germanium (HPGe) detector. The activity concentrations of 226Ra, 228Ra and 40K...

Assessment of outdoor radiation hazard of natural radionuclides in tourism beach areas

Tourism beaches are main attractions visited by members of the public for leisure and holidays. Knowledge of radiation hazard would enable the radiation risk estimation to be made, and suggest mitigation steps if needed. Surface radiation dose, activity concentration of ²³⁸U, ²³²Th and ⁴⁰K, and radiation hazard index in 18 beaches at eastern, south western and southern coast of Peninsular Malaysia were determined. In-situ surface radiation dose measurements were done using portable radiation survey meter, while gamma-ray activities of sand samples were measured by using gamma-ray spectrometry method. The surface dose rates were found to range between 0.04 to 0.12 (μSv hr⁻¹. Mean activity concentration of ²³⁸U varies between 7.3 to 51.0 Bqkg⁻¹, ²³²Th between 5.9 and 58.4 Bqkg⁻¹ while ⁴⁰K between 32.7 and 1293 Bqkg⁻¹ respectively. The corresponding annual effective dose from these natural radiations ranged between 0.051 and 0.552 mSv/y. This average is way below the average worldwide exposure of 2.4 mSv/y. The external radiation hazard index calculated for the eighteen samples ranged between 0.05 and 0.51. No obvious correlation was observed between in-situ dose measurement with the annual effective dose as well as radiation hazard index.

Effectiveness of mineral soil to adsorb the natural occurring radioactive material (norm), uranium and thorium

A study has been performed on U-soil and Th-soil adsorption of three types of soil collected from Selangor State of Malaysia which are Saujana Putra, Bukit Changgang and Jenderam Hilir. In this study, natural radionuclide (U and Th) soil adsorption based on batch experiments with various initial concentrations of the radionuclide elements were carried out. Parameters that were set constant include pH at 5;amount of soil used was 5 g each, contact time was 24 hour and different initial concentration for each solution of U and Th which is 5 mg/L, 10 mg/L, 15 mg/L, 20 mg/L, 25 mg/L and 40 mg/L were used. The Kd values for each type of soil were determined in this batch experiments which was based on US-EPA method, in order to estimate adsorption capacity of the soil.The Kd values of Th found higher than Kd values of U for all of the soil samples, and the highest was found on the soil collected from Bukit Changgang. The soil clay content was one of factors to influence the adsorption of both U and Th from dil...

Measurement of natural radioactivity levels in soil samples in research station at National Park area in Malaysia

Taman Negara or National Park is a reserve for natural or semi natural land and restricted from most development. In this area, depending on the geological condition of the surrounding, it may contain some natural radionuclides which emit certain amount or levels of radiation In this study natural radionuclides (226Ra, 228Ra and 40K) activity concentrations in soil and the corresponding surface doses at eleven locations around UiTM-Perhilitan Research Station Taman Negara, Pahang were determined to assess the possible radiation hazard to visitors in that area. The gamma activities and the surface doses were determined using high resolution gamma-ray spectrometer and portable radiation survey meter. The mean activity concentrations in the area for 226Ra, 228Ra and 40K are 99.13 Bq/kg, 139.98 Bq/kg and 598.24 Bq/kg respectively, while on average the doses are 0.215 μSv/hr on the ground and 0.193 μSv/hr at one meter from ground. The activities were higher than world average and doses were in the ranges, while radiation hazard indices were slightly greater than unity in four locations.

Determination of heavy metals concentrations in airborne particulates matter (APM) from Manjung district, Perak using energy dispersive X-ray fluorescence (EDXRF) spectrometer

Airborne particulates trace metals are considered as public health concern as it can enter human lungs through respiratory system. Generally, any substance that has been introduced to the atmosphere that can cause severe effects to living things and the environment is considered air pollution. Manjung, Perak is one of the development districts that is active with industrial activities. There are many industrial activities surrounding Manjung District area such as coal fired power plant, quarries and iron smelting which may contribute to the air pollution into the environment. This study was done to measure the concentrations of Hg, U, Th, K, Cu, Fe, Cr, Zn, As, Se, Pb and Cd in the Airborne Particulate Matter (APM) collected at nine locations in Manjung District area within 15 km radius towards three directions (North, North-East and South-East) in 5 km intervals. The samples were collected using mini volume air sampler with cellulose filter through total suspended particulate (TSP). The sampler was set up for eight hours with the flow rate of 5 L/min. The filter was weighed before and after sample collection using microbalance, to get the amount of APM and kept in desiccator before analyzing. The measurement was done using calibrated Energy Dispersive X-Ray Fluorescence (EDXRF) Spectrometer. The air particulate concentrations were found below the Malaysia Air Quality Guidelines for TSP (260 µg/m3). All of the metals concentrations were also lower than the guidelines set by World Health Organization (WHO), Ontario Ministry of the Environment and Argonne National Laboratory, USA NCRP (1975). From the concentrations, the enrichment factor were calculated.Airborne particulates trace metals are considered as public health concern as it can enter human lungs through respiratory system. Generally, any substance that has been introduced to the atmosphere that can cause severe effects to living things and the environment is considered air pollution. Manjung, Perak is one of the development districts that is active with industrial activities. There are many industrial activities surrounding Manjung District area such as coal fired power plant, quarries and iron smelting which may contribute to the air pollution into the environment. This study was done to measure the concentrations of Hg, U, Th, K, Cu, Fe, Cr, Zn, As, Se, Pb and Cd in the Airborne Particulate Matter (APM) collected at nine locations in Manjung District area within 15 km radius towards three directions (North, North-East and South-East) in 5 km intervals. The samples were collected using mini volume air sampler with cellulose filter through total suspended particulate (TSP). The sampler was set u...

Heavy Metals in Lichens and Mosses of a Tea Plantation in Cameron Highlands, Malaysia

Lichen species Platismatia glauca and moss species Meiothecium microcarpum were used as bio-indicator for heavy metals pollutants of anthropogenic origins. These species are found to grow extensively and abundantly on the stems and branches of tea plant in the study area. The elemental analyses of heavy metals were carried out using Energy Dispersive X-rays Fluorescence Technique (EDXRF). Results showed that the mean concentration of the metals can be arranged in decreasing order as Zn > Cu > Pb > Cr > Cd > As > Ni for lichen and Zn > Cu > Pb > Ni > Cr > Cd > As for moss. Analysis of pollution based on anthropogenic factor (AF) indicated that only Cd shows slightly polluted, and Zn potentially polluted. However, the mean pollution impact based on pollution index (PI) shows a value of 0.38 and 0.29 for lichen and moss respectively, indicating the impact is still low. The sources of the two important metals, Cd and Zn can be traced to solid waste disposal, fossil fuel burning and application of phosphate fertilizers, which are the peculiar anthropogenic activities of the area.

Measurement of natural radionuclides in the soil of Highlands agricultural farmland

Natural occuring radioctive material (NORM) is distributed in the environment including soil. It consist the gamma emmiting radionuclides such as 40K, the decay products of 238U and 232Th such as 214Bi, 214Pb (representing 226Ra) and 228Ac (representing 228Ra). This study was carried out to determine the radioactivity concentration of NORM in soil, to calculated the radium equivalent, absorbed dose, annual effective dose and external hazard index level for the study area. The measurement was done by using gamma spectrometer with high resolution hyperpure germenium (HPGe) detector. Soil samples were collected using hand auger from the highland agricultural farm area in Cameron Highlands. These samples were dried, pulverized and sieved prior to analysis. The range of the radionuclides activity concentration for 40K is 363.6 to 1244.1Bq Bq/kg; range for 226Ra is 131.1 to 200.0 Bq/kg 228Ra 18.6 to 237.7 Bq/kg and Radium equivalent activity range 222 to 453 Bq/kg; 153.2 to 263.8 nGy/h is the range for absorbed dose rate while annual dose range from 0.17 to 0.30 mSv. External hazard index is in the range of 0.92–1.54, which are higher than unity. These value should be less than unity in order to keep the radiation hazard to be insignificant. Therefore, it can be concluded that soil from this study area might be contaminated by the fertilizer applied to the the plants itself and from the geological and geographial location soil types.

Measurements of natural radioactivity in soil of Fraser’s Hill, Pahang, Malaysia

Surface soils of 2 cm depth were sampled at developed and undeveloped areas in Fraser’s Hill, Pahang, Malaysia. Thirty one (31) locations were collected and 226Ra, 232Th and 40K activity concentrations were measured using HPGe Gamma Counting System. The mean radium equivalent activity concentration (Raeq) for the sampled area was 463.37 Bq/kg. The Undeveloped area was found to have higher mean of Raeq compared to Developed area. The mean Raeq for each area was found to be 614.07 Bq/kg and 354.53 Bq/kg respectively. The external hazard index (Hex) were calculated and found to have a mean of 1.251. Undeveloped area was found to have higher mean of 1.658 compared to developed area with a mean of 0.957. Many locations were found to have Hex higher than 1.000.