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Journal Article

Effective dose from natural background radiation in Keffi and Akwanga towns, central Nigeria

15 Jan 2014-Iranian Journal of Radiation Research (International Journal of Radiation Research)-Vol. 12, Iss: 1, pp 47-52

AbstractBackground: Human is exposed to radiaƟ on in their environment with or without their consent; and the exposure to natural background radiaƟ on is an unpreventable event on earth. Materials and Methods: An in situ assessment of the indoor and outdoor background radiaƟ on in Akwanga and Keffi towns of Nasarawa state Nigeria was carried out using a halogen-quenched Geiger Muller (GM) detector (Inspector alert Nuclear radiaƟ on monitor SN: 3544). Each of these towns was divided into at least 20 sampling areas where at least ten readings were taken in order to have a reliable data. Results: The mean indoor and outdoor annual effecƟ ve dose of Akwanga were 1.29± 0.13mSv/yr and 0.31±0.04 mSv/yr respecƟ vely; and that of Keffi were 1.08± 0.15mSv/yr and 0.25±0.04 mSv/yr respecƟ vely. The radiaƟ on levels in both highly populated towns were found to be within the safe limit for areas of normal background set by UNSCEAR (2.4 mSv/yr). Conclusion: These results would serve as a baseline upon which other exposures would be assessed and in the future, serve as reference for dosimetry and decontaminaƟ on in situaƟ ons of radiaƟ on poisoning of these towns.

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Journal ArticleDOI
TL;DR: A pioneer data for ecological risk from ionizing contaminants due to mining activity in Nasarawa State, Nigeria is presented and could be adopted for future work on radioecology of mining.
Abstract: Nasarawa State is located in north central Nigeria and it is known as Nigeria's home of solid minerals. It is endowed with barite, copper, zinc, tantalite and granite. Continuous releases of mining waste and tailings into the biosphere may result in a build-up of radionuclides in air, water and soil. This work therefore aims to measure the activity concentration levels of primordial radionuclides in the soil/sediment samples collected from selected mines of the mining areas of Nasarawa State. The paper also assesses the radiological and radio ecological impacts of mining activities on the residents of mining areas and their environment. The activity concentrations of primordial radionuclides ((226)Ra, (232)Th and (40)K) in the surface soils/sediment samples were determined using sodium iodide-thallium gamma spectroscopy. Seven major mines were considered with 21 samples taken from each of the mines for radiochemistry analysis. The human health hazard assessment was conducted using regulatory methodologies set by the United Nations Scientific Committee on the Effects of Atomic Radiation, while the radio ecological impact assessment was conducted using the ERICA tool v. 1.2. The result shows that the activity concentrations of (40)K in the water ways of the Akiri copper and the Azara barite mines are 60 and 67% higher than the world average value for (40)K, respectively. In all mines, the annual effective dose rates (mSv y(-1)) were less than unity, and a maximum annual gonadal dose of 0.58 mSv y(-1) is received at the Akiri copper mine, which is almost twice the world average value for gonadal dose. The external hazard indices for all the mines were less than unity. Our results also show that mollusc-gastropod, insect larvae, mollusc-bivalve and zooplankton are the freshwater biotas with the highest dose rates ranging from 5 to 7 µGy h(-1). These higher dose rates could be associated with zinc and copper mining at Abuni and Akiri, respectively. The most exposed terrestrial reference organisms are lichen and bryophytes. In all cases, the radio ecological risks are not likely to be discernible. This paper presents a pioneer data for ecological risk from ionizing contaminants due to mining activity in Nasarawa State, Nigeria. Its methodology could be adopted for future work on radioecology of mining.

20 citations


Cites background from "Effective dose from natural backgro..."

  • ...Map of Nasarawa State in Nigeria and the area of investigation [39]....

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Journal ArticleDOI
Abstract: A study to assess the outdoor Background Ionizing Radiation (BIR) levels in Emene Industrial Layout of Enugu State, Nigeria has been conducted. An in-situ measurement of BIR exposure rate in mRh-1 for 30 locations was done using a well calibrated portable GQ GMC-320 PLUS nuclear radiation detector at an elevation of 1.0 m above ground level with a geographical positioning system (GPS) for geographical location. The measured BIR exposure rates were used to evaluate the radiological health hazards and radiation effective doses to different body organs using well established radiological relations. The obtained values were compared with recommended permissible limits to ascertain the radiological health status of the environment. The mean values of BIR exposure levels (0.015±0.001 mRh-1), absorbed dose rates (126.15±5.10 ηGyh-1) and excess lifetime cancer risk (0.541±0.032×10-3) are higher than their recommended safe limits of 0.013 mRh-1, 84.0 ηGyh-1, 0.29×10-3 respectively as recommended by ICRP and UNSCEAR. The mean annual effective dose equivalent (0.155±0.006 mSvy-1) is within recommended permissible limits of 1.00 mSvy-1 for general public exposure. Also, the effective doses to different body organs are all below the recommended limits of 1.0 mSvy-1. Generally, the study shows that Emene Industrial Layout is radiologically contaminated due to industrial activities taking place. However, the contamination does not constitute any immediate radiological health effect on resident of the area but there is the potential for long-term health hazards in the future such as cancer due to accumulated doses. Key words: BIR exposure level, effective dose, industrial activities, Emene Industrial Layout.

14 citations


Journal ArticleDOI
Abstract: Terrestrial gamma radiation dose rates (TGRD) of Kelantan State were measured in situ using a portable [NaI(TI)] micro roentgen (µR) survey meter. The TGRD rates ranged between 44 and 500 nGy h−1 with a mean value of 209 ± 8 nGy h−1. The distribution of these measurements in various districts of the state shows the statistically the influence of geology and soil types on the dose rate values. The data obtained could be used in formulating safety standard and radiological guidelines.

10 citations


Cites background from "Effective dose from natural backgro..."

  • ...Men are exposed to radiation in their environment with or without their consent and the exposure to natural background radiation is an unpreventable event [1, 2]....

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Journal ArticleDOI
Abstract: A study of the external background ionizing radiation (BIR) levels in eight solid mineral mining sites in Enugu State has been carried out using two Digilert radiation monitors Radalart-50 and Radalart-100. Thirty two readings of four samplings in each point were taken at different solid mineral sites of the state following standard procedure. The measured BIR levels obtained ranged from 0.012 mR/hr in Nkpologwu silica mining site to 0.028 mR/hr in clay mining site in Enugu-Ekulu with an average of 0.018 ± 0.004 mR/hr, while the corresponding calculated equivalent dose rate ranged from 1.0 mSv/yr to 2.35 mSv/yr with a mean value of 1.51 ± 0.04 mSv/yr. The result obtained indicates that the average exposure level of the studied area is 38.5% higher than the international standard. This suggests the possibility of the presence of radionuclide in the solid minerals mined in Enugu state. However, the values obtained may not cause immediate health challenge to miners and those engaging in commercial activities around these mining sites in Enugu, but may result in long-term health side-effects to residence and miners who put in over twenty-five years in the job. From the forgoing, it is recommended that control mechanism should be adopted for the members of the public, residence, commercial traders as well as miners working in these sites, and to protect the environment.

7 citations


Cites background from "Effective dose from natural backgro..."

  • ...The International Atomic Energy Agency (IAEA) estimate of the dose contribution to the environment shows that, over 85% of background radiation received by man is derived from natural radionuclides, while the remaining 15% is from cosmic rays and nuclear process [3]....

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Journal ArticleDOI
Abstract: Mining of tin and other related activities have been active and thus leading to economic growth in the Jos area of Nigeria for more than a century. However, mining of minerals has been confirmed to enhance the concentrations of heavy metals and natural radioisotopes in the soil, air and water bodies in the environment. In an attempt to evaluate the radiological burdens resulting from tin mining activities at Rayfield-Du area of Jos, specific activities of naturally occurring radioactive nuclei (238U, 232Th and 40K) concentrations were evaluated in soil samples collected from the mine site. The soil samples were classified as normal soil (S), tailings (T) and mineral soils (M) and their corresponding mean activities for 238U, 232Th and 40K were analysed using an HpGe detector-based gamma spectrometric system. The mean activity concentration for 238U, 232Th and 40K were 323.44, 877.63 and 864.99 Bq/kg, 138.84, 469.31 and 578.65 Bq/kg and 168.83, 436.08 and 346.1 Bq/kg, respectively for M, T and S samples. The calculated radiation dose parameters for the soil samples were all higher than the recommended safety limit. For all the collected soil samples, the external hazard risk Hext were 2.21, 2.81 and 4.44 for S, T and M, respectively while the mean calculated radium equivalent was 819, 1057 and 1645 Bq/kg for S, T, and M, respectively. The excess lifetime cancer risk estimated for the mine was more than the world average value. The radio-ecological dose rate estimate for non-human biota in the mine revealed that all non-human species except lichen and bryophyte had absorbed dose rate less than the 10 µGy/h screening dose.

5 citations


Cites background from "Effective dose from natural backgro..."

  • ...Similar uranium enrichment has been reported earlier in mine soils (Arogunjo et al. 2009; Ibeanu 2003; Ramli et al. 2014; Olise et al. 2014)....

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  • ...The geochemical composition and description of an area has been confirmed to influence the radiological content in the soil and rocks found in such area (Ademola 2008; Ramli et al. 2014; Arogunjo et al. 2009; Olarinoye et al. 2010)....

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References
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Abstract: GEOLOGY - IGNEOUS AND METAMORPHIC ROCKS.- The Basement Complex.- The Younger Granites.- GEOLOGY - SEDIMENTARY BASINS.- Cretaceous - Cenozoic Magmatism and Volcanism.- The Benue Trough.- The Bornu Basin (Nigerian Sector of the Chad Basin).- The Sokoto Basin (Nigerian Sector of the Iullemmeden Basin).- The Mid-Niger (Bida) Basin.- The Dahomey Basin.- MINERAL RESOURCES.- The Niger Delta Basin.- Solid Mineral Resources.- Petroleum Resources.- Policy Issues and Development Options.

475 citations


Journal ArticleDOI
TL;DR: Inhabitants of high background radiation areas had about 56% the average number of induced chromosomal abnormalities of normal background radiation area inhabitants following this exposure, which suggests that adaptive response might be induced by chronic exposure to natural background radiation as opposed to acute exposure to higher levels of radiation in the laboratory.
Abstract: People in some areas of Ramsar, a city in northern Iran, receive an annual radiation absorbed dose from background radiation that is up to 260 mSv y−1, substantially higher than the 20 mSv y−1 that is permitted for radiation workers. Inhabitants of Ramsar have lived for many generations in these hig

369 citations


"Effective dose from natural backgro..." refers background in this paper

  • ...Previous studies have shown that areas with high background radiation are found in Yangjiang, China; Kerele, India; and Ramsar, Iran (7); and in Asia, maximum outdoor measurement was recorded in Malaysia and the maximum indoor measurement was recorded in Hong A....

    [...]

  • ...Previous studies have shown that areas with high background radiation are found in Yangjiang, China; Kerele, India; and Ramsar, Iran (7); and in Asia, maximum outdoor measurement was recorded in Malaysia and the maximum indoor measurement was recorded in Hong Background: Human is exposed to radia on in their environment with or without their consent; and the exposure to natural background radia on is an unpreventable event on earth....

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Journal ArticleDOI
Abstract: The outdoor radiation exposure dose rates due to the radioactivity concentration of 40 K, 238 U and 232 Th in the soil across different environments in Nigeria have been carried out using the low-cost method of in situ γ ray spectrometry. Measurements were made in 18 cities, spread across the three major zones of the country. The radioactivity concentrations of these radionuclides in the soil were used to determine their radiation absorbed dose rates in the air. The range of average total dose rate due to the three radionuclides in the Eastern zone is between 0.025 and 0.081 μGy.h -1 with an average of 0.040 ± 0.006 μGy.h -1 , 0.041 and 0.214 μGy.h -1 with a mean of 0.089 ± 0.014 μGy.h -1 for the Western zone and between 0.066 and 0.222 μGy.h -1 with a mean of 0.102 ± 0.032 μGy.h -1 for the Northern zone. The average annual outdoor effective dose equivalents of 51 ± 8 μSv.y -1 114 ± 18 μSv.y -1 and 130 ± 41 μSv.y -1 have been estimated for the Eastern, Western and Northern zones, respectively. The average annual effective dose equivalent for the country has been estimated to be 98 ± 15 μSv.y -1 and the collective effective dose equivalent as 9.7 X 10 3 man.Sv.y -1 . Measurements have been taken as representing the baseline values of natural radioactivity as no artificial radionuclide was detected at any of the sites surveyed.

67 citations


Journal Article
TL;DR: The average annual effective dose for gamma background radiation in Lorestan province has been 0.72 mSv, which was more than the global value (0.48 mSV) and a poor correlation coefficient between was observed altitude and absorbed dose rates.
Abstract: Background: The exposure of human being to ionize radiation from natural sources is a continuing, inescapable feature of life on earth. Direct measurement of absorbed dose rates in air has been carried out in many countries of the world during the last few decades. Such investigations can be useful for assessment of public dose rates, the performance of epidemiological studies, and keeping reference-data records to ascertain possible changes in the environmental radioactivity duo to nuclear, industrial, and other human activities. Materials and Methods: The measurements of the outdoor and indoor- environmental exposures including cosmic and terrestrial components were accomplished by a portable Geiger Muller detector (RDS -110). The measurements were made during daylight from September to October 2009, in five areas within nine big cities of Lorestan province. In each area, one building was randomly selected for indoor and outdoor measurements. Measurements were made for each region and an average value was used to calculate the exposure rate from gamma background radiation. Results: The results showed the Maximum and minimum outdoor dose rates as 166±44 and 65±8 nSvh-1 in Borujerd and Pol-e- dokhtar, respectively. The average of outdoor dose rates was determined 113±26 nSvh-1. Also the maximum and minimum values of indoor dose were 157±52 and 74±14 nSvh-1 in Borujerd and Pol-e-dokhtar, respectively. The average indoor dose rates were determined as 119±27 nSvh-1. Conclusion: The average annual effective dose for gamma background radiation in Lorestan province has been 0.72 mSv, with the range of 0.3– 0.6 mSv which was more than the global value (0.48 mSv). A poor correlation coefficient between was observed altitude and absorbed dose rates. Iran. J. Radiat. Res., 2011; 9(2): 89­93

29 citations


Journal ArticleDOI
TL;DR: Results indicate that the indoor background gamma radiation is comparable for both mining environments, and the outdoor gamma dose rates appear to be generally lower at the Okaba open cast mine than at Okpara.
Abstract: Measurements of the background terrestrial gamma radiation dose rates at different indoor and outdoor locations on the surfaces of Okpara underground and Okaba open cast mines in Nigeria were made. Two duly calibrated low-level gamma survey metres were held 1 m above the ground surface for these measurements. Measurements were also made at various locations inside the mine tunnel at the Okpara mine. Results indicate that the indoor background gamma radiation is comparable for both mining environments. The mean outdoor gamma dose rate determined for the Okaba mining environment is 10.4 nGy h - 1 as against 11.7 nGy h - 1 for Okpara. The ranges are 8.5-16.5 nGy h - 1 for the Okpara measurements and 7.5-14.0 nGy h - 1 for Okaba. Thus, the outdoor gamma dose rates appear to be generally lower at the Okaba open cast mine than at Okpara. The indoor dose rate values range from 11.0 to 17.0 nGy h - 1 in both environments. These indoor measurements have nearly the same mean values 14.4 and 14.5 nGy h - 1 for Okpara and Okaba environments, respectively. The indoor to outdoor dose rate ratio is 1.2 for Okpara and 1.4 for Okaba. These values are in consonance with the corresponding ratio given in literature. Dose rate measurements inside the mine tunnel at the Okpara mine are higher than the surface indoor measurements ranging from 13.5 to 20.5 nGy h - 1 with a mean of 16.5 nGy h - 1 . The higher dose rate values measured in the mine tunnel are attributable to the concentration of radon in the 'closed' environment of the mine tunnel.

15 citations