Natural Radioactivity Measurements To Determine The Radiation Hazards From Surface Soil And Effluents In Agbara Industrial Estate , Ogun State , Nigeria (original) (raw)
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Journal of African Earth Sciences, 2016
Ground investigations of the activity concentrations from primordial radionuclides (238 U, 232 Th and 40 K) were conducted in Akpabuyo, southeastern Nigeria. These investigations were aimed at assessing the magnitude and spatial distribution of activity concentrations from primordial radionuclides. Also, radiological hazard assessment and their associated risk to both human environmental healths and suitability of soils in the area for constructing dwellings places will be made. Instrument used for the investigations, which were conducted both randomly and along 6 profiles with inter-profile distance of 100 m, was a potable GRS-2 model of a Pico Envirotec spectrometer. Activity concentrations in the area, which vary with spatial distribution of soil texture, lithology, land use and topography, range between 2.22 and 116.09 Bq kg À1 (mean of 34.67 Bq kg À1) for 238 U, 3.65e87.41 Bq kg À1 (mean of 38.59 Bq kg À1) for 232 Th and 6.26e384.99 Bq kg À1 (mean of 114.66 Bq kg À1) for 40 K. The mean activity concentrations of 238 U and 232 Th are marginally higher than world averages of 30 and 39 Bq kg À1 respectively. However, the activity concentration of 40 K, which is the most abundant radionuclide (60.02%), is less than the world average of 400 Bq kg À1. Results obtained from skew and kurtosis analyses of the activity concentration data show that the distribution of 238 U and 232 Th radionuclides in the soils is nearly symmetrical. The radiological hazard indicators computed from the activity concentrations of the radionuclides are all below maximum permissible limits. For instance, values of radium equivalent, which vary from 41.72 to 171.02 Bq kg À1 (average of 98.68 Bq kg À1), are below the permissible limit of 370 Bq kg À1. External and internal hazard indices vary between 0.11 and 0.46 Bq kg À1 (mean of 0.27 Bq kg À1) and 0.14e0.72 Bq kg À1 (mean of 0.36 Bq kg À1) respectively. These results are below the 1 Bq kg À1 benchmark required for materials to be safe for use in constructing residential buildings. Absorbed dose, indoor and outdoor annual effective dose rates vary from 19.37 to 76.72 nGy h À1 (mean of 44.11 nGy h À1), 0.10e0.38 mSv yr À1 (mean of 0.22 mSv yr À1) and 0.02e0.09 (mean of 0.05 mSv yr À1) respectively. The mean absorbed dose rate is almost equal to the world average of 44 nGy hr À1 , but the means of the indoor and outdoor annual effective doses are below the 0.50 mSv yr À1 limit set for materials to be safe. Thus, the soils in Akpabuyo are safe for use in constructing dwelling places for the population. However, periodical monitoring of the radionuclides and radioisotopes should be performed.
International Journal of Low Radiation, 2009
Abeokuta and Jos Plateau, towns in the southwestern and northern parts of Nigeria, respectively, are situated in areas of high background radiation. The use of farm soil for the construction of dwellings by local residents and for agricultural purposes in these areas may present scenarios for both enhanced external and internal exposure pathways to the population. In order to assess the gamma radiation exposure levels, soil samples from 65 farms in Jos Plateau and 47 farms in Abeokuta were collected. Using gamma-ray spectroscopy the activity concentrations of 226 Ra, 232 Th and 40 K in the samples were determined. From the activity concentrations of these radionuclides, the absorbed gamma dose rates were calculated. The obtained mean total absorbed gamma dose rates varied between 194 ± 59 nGy h-1 and 350 ± 270 nGy h-1 in Jos Plateau, whereas in Abeokuta, it was 167 ± 140 nGy h-1. These results, along with the results of the estimated annual effective dose rates, radium equivalent (Ra eq), external hazard index (H ex), internal hazard index (H in) and gamma index (I γ), are presented in this paper. The results of this study indicate that the populations in the investigated areas are likely subjects for high radon burden in their dwellings.
Soil samples collected from five states in the southwestern part of Nigeria have been analyzed for activity concentration of gamma-ray emitters. The States were Oyo, Lagos, Ondo, Ogun, and Osun. Activity concentration measurement was carried out using a co-axial type high purity germanium (HPGe) detector. Spectral analyses were performed using spectrometry software. The activity concentration measured ranged from 0.03 ؎ 0.2 Bq kg ؊1 for 137 Cs to 1,358.6 ؎ 28.5 Bq kg ؊1 for 40 K. 40 K accounted for most of the activity. The calculated absorbed dose rates in air at 1.0 m above the ground ranged from 6 to 303 nGy h ؊1 with a mean and standard deviation of 60.5 nGy h ؊1 and 63.2 nGy h ؊1 , respectively. Estimated annual outdoor effective dose equivalent varied from 8 to 370 mSv y ؊1 . The calculated collective dose equivalent values for the five states ranged from 87,000 person-Sv to 600,000 person-Sv. The estimated annual outdoor effective values were considerably higher than the world soil average value of 70 Sv y ؊1 reported by the International Commission on Radiological Protection. Health Phys. 94(6):558 -566; 2008
Natural radiation levels and health hazard indices of soil in Owerri Nigeria
The natural radiation of soil samples from three local governments areas that make up Owerri city in Imo state, Nigeria were measured using gamma ray spectrometer. The mean values obtained were 167.2 ± 10.5 ( ), 19.7 ± 1.9 ( ) and 18.1 ± 3.3 ( ) for 40 K , 226 Ra and 232 Th respectively. These values were used to evaluate the radiological health hazard indices using standard analytical methods. The results showed that the mean value of radium equivalent activity is 58.5 , while the values of absorbed dose rate ( ) and annual effective dose equivalent ( ) are 27.1 and 132.78 respectively. The values of external and internal health hazard indices are 0.16 and 0.21 respectively. All these values obtained are lower than their world permissible United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR) values for such environment. This shows that the risk due to radiation contamination in the city of Owerri is low.
Radioactivity of surface soils from Oyo state, South Western Nigeria
The ac vity concentra ons of some radionuclides in soil samples collected from 20 loca ons in 8 major towns in Oyo State, Southwestern Nigeria have been determined by gamma-ray spectrometry technique. Materials and Methods: The ac vity concentra ons were determined using high-purity germanium (HPGe) detector (Canberra Industries Inc.). The outdoor absorbed dose rates in air at about 1.0 m height were es mated from the ac vity concentra ons and dose rate conversion factors for the radionuclides. The annual outdoor effec ve dose equivalent rates were also es mated for urban and rural areas of the state using the calculated absorbed dose rates in air. Results: Determined specific ac vity concentra ons of the radionuclides ranged from 1±0.4 Bq kg -1 for 137 Cs to 1190±30 Bq kg -1 for 40 K. The es mated outdoor absorbed dose rates in air varied from 52 nGy h -1 in Egbeda (a rural area) to 414 nGy h -1 in Eruwa (also a rural area). The mean annual outdoor effec ve dose equivalent for the urban areas in the state was 0.1 mSv y -1 while that of rural areas was 0.3 mSv y -1 with a standard devia on of 0.02 mSv y -1 and 0.3 mSv y -1 respec vely. The mean for the study area was 0.2 mSv y -1 . Conclusion: The mean annual outdoor effec ve dose values for the urban and rural areas, for the whole study area are higher than the world average annual outdoor terrestrial radia on value of 0.07 mSv y -1 reported by the United Na ons Scien fic Commi ee on Effects of Atomic Radia on (UNSCEAR) for individual members of the public.
Radiation hazard in soil from Ajaokuta North-central Nigeria
International journal of radiation research, 2017
Background: Measurement of the radia on dose distribu on is important in assessing the health risk a popula on and serve as reference in documen ng changes to environmental radioac vity in soil due to man-made ac vi es. Materials and Methods: The ac vity concentra on of 238 U, 232 Th and 40 K in soil samples obtained from different loca ons in Ajaokuta Local Government area was measured using Hyper Pure germanium Detec on System (HPGe). Results: The calculated average concentra on of the radionuclides ranged from 12 ± 1 Bqkg-1 to 59 ± 2 Bqkg-1 for 238 U, 14 ± 1 Bqkg-1 to 78 ± 5 Bqkg-1 for 232 Th and 49 ± 2 Bqkg-1 to 1272 ± 23 Bqkg-1 for 40 K. In order to evaluate the radiological hazards due to natural radionuclides within Ajaokuta, the absorbed dose rate, gamma index, radium equivalent and excess life me cancer risk were es mated. According to measured data from the top soil (0-10 cm), the es mated radium equivalent (Ra eq) ranges from 55.7 Bqkg-1 at Steel Complex to 253.3 Bqkg-1 obtained from Forest samples. Conclusion: The mean absorbed dose rate, annual effec ve dose and gamma radia on index evaluated were 66.2 nGyh-1 , 81.2 µSvy-1 and 1.05 respec vely which are higher than the recommended limit for normal background radia on. Thus, we conclude that people living in these loca ons may be exposed to higher radia on.
In this work, the activity concentration of some radionuclides in soil samples collected from 10 locations in Guma local government area of Benue State Nigeria have been determined using Gamma ray spectroscopy. (Model: 3M3/3). The soil activity for urban areas ranged from 38.12-58.10Bq/kg, 3.53-4.41Bq/kg, and3.35-7.11Bq/kg for 40 K, 238 U and 232 Th respectively for urban areas while in the rural areas the concentrations ranged from 54.06-76.17Bq/kg, 3.66-5.27Bq/kg and 4.74-7.18Bq/kg 40 K, 238 U and 232 Th respectively. The absorbed dose and annual effective dose range from 5.89-7.70nGy/h and 0.01mSv/y in the urban areas with mean of 6.48nGy/h and 0.01mSv/y while in the rural area, the values ranges from 7.48-8.52nGy/h and 0.01-0.02mSv/y with mean values of 8.00nGy/h and 0.01mSv/y. All the computed values are much lower than permissible value recommended by the United Nation for Scientific Committee on Effect of Atomic Radiation UNSCEAR but lower than the values reported by (Avwiri and Ononugbo, 2012) and (Ajayi et al; 2013).
International Journal of Scientific and Research Publications (IJSRP), 2018
Studies on the gamma radiation level and the radionuclide distribution in the soil of Ladoke Akintola University of Technology (LAUTECH), Ogbomoso, Oyo state were carried out. This study is to provide a baseline data on the radiation level as well as the distribution of some naturally occurring radionuclides present in the University that was established in 1990 with population of about thirty thousands. The analysis was carried out through the use of a well calibrated NaI(TI) detector system. The range of activity concentration of (40 K, 234 U and 232 Th) were found to be (50.23±1.41 to 183.55±1.42, 9.81±3.11 to 22.70±3.15 and 9.07±0.95 to 34.42±0.78) Bq/kg respectively. The mean absorbed dose rate and annual effectively dose equivalent (AEDE) were calculated and found as presented: 23.06µSvy-1 and 23.16µSvy-1 respectively. The values obtained were below the safety limit of 1mSv/y as recommended by the International Commission on Radiological Protection.
Baseline Radionuclide Distribution Patterns in Soil and Radiation Hazard Indices for Abak, Nigeria
Advances in Physics Theories and Applications, 2014
A gamma spectroscopy analysis for the naturally occurring radionuclides 226 Ra, 232 Th and 40 K has been carried out for soil samples collected from communities in Abak Local Government Area of Akwa Ibom State to determine the concentration and distribution patterns of these radionuclides in the study area and to assess the possible radiological risks from the soil. The activity concentration of the samples range from 14.80±1.16Bq/kg to 150.20±11.47Bq/kg with a mean value of 98.709±7.693Bq/kg for 40 K; from 14.52±3.49Bq/kg to 42.04±8.59Bq/kg for 238 U with a mean of 24.826±5.425Bq/kg and from 3.05±0.27Bq/kg to 7.00±0.58Bq/kg with a mean of 5.172±0.31Bq/kg for 232 Th. These values are within international regulatory standards. Assessment of the radiation hazard levels for the area gave values of 18.789±3.102nGy/h for absorbed dose, 0.3±0.05Bq/kg for representative level index, 39.82±6.65Bq/kg for radium equivalent, 0.11±0.02 for external hazard index, 0.18±0.032 for internal hazard index and 0.023±0.004mS/yr for effective dose rate. These indices are much lower than the ICRP permissible limits for soil showing that the soil of the study area poses no radiological threats to the public.
This study assesses the level of natural radioactivity due to radionuclides, 238U, 232Th and 40K, in 16 soil samples collected from 16 locations in Akure township, Ondo State, Nigeria. The activity concentrations of 238U, 232Th and 40K varied from 0.15 to 4.41 Bq kg−1, 4.21 to 9.92 Bq kg−1, and 167.79 to 419.52 Bq kg−1, respectively, with mean values of 1.29±1.39 Bq kg−1, 6.98±1.82 Bq kg−1 and 278.16±69.40 Bq kg−1 respectively, measured from all the soil samples studied. The mean total absorbed dose rate was obtained and the value is 16.89 nGy.h-1 . This average calculated absorbed dose rate in air was found to be much lower than the world average of 57 nGy h−1. The outdoor annual effective dose equivalent ranged from 12.82 to 30.25 μSv.y-1 with mean of 20.71 μSv y-1. This is considered to be low when compared to natural external radiation of about 2000 μSvy-1 to which no harmful effect is expected directly.