Evaluation of Absorbed Dose Rate and Annual Effective Dose Equivalent due to Terrestrial Gamma Radiation in Rocks in a Part of Southwestern Nigeria

2002 ◽  
Vol 98 (4) ◽  
pp. 441-444 ◽  
Author(s):  
O.S. Ajayi
2021 ◽  
Vol 5 (1) ◽  
pp. 34-51
Author(s):  
E C D K Addison ◽  
R A Opoku ◽  
C E B N Addison ◽  
W I Aniagyei

Purpose: A study was conducted to estimate the Annual Effective Dose Equivalent (AEDE) and Excess Lifetime Cancer Risk (ELCR) caused by the presence of an artificial cobalt-60 radioactive source producing ionizing radiation levels within the radiotherapy facility at Komfo Anokye Teaching Hospital (KATH) in Ghana. This study validated the safety of cobalt-60 radioactive sources, as well as the notion of calculating the Annual Effective Dose Equivalent (AEDE) and Excess Lifetime Cancer Risk (ELCR), which contributed to reducing occupational and public exposures inside the facility. Methodology: The investigation was carried out with the use of a portable OD-01 Ionization Chamber Survey Meter. The absorbed dose rate (ADR) in air was changed between 5 m and 40 m, with measurements taken inside and around the cobalt 60 bunker, as well as at sixteen other sites within the radiation facility. Findings: From 5 m to 40 m surrounding the Cobalt-60 source, the estimated Absorbed Dose Rate in air inside the cobalt-60 bunker ranged from 0.299 0.001 to 0.977 0.005 Sv/h, with an average of 0.498 0.005 Sv/h. The estimated Annual effective dose equivalent varied from 1.100 mSv/yr to 3.595 mSv/yr around the cobalt-60 source inside the Co-60 bunker. Radiation exposure levels ranged from 0.268 0.008 Sv/h to 0.678 0.005 Sv/h, with an average of 0.440 0.004 Sv/h observed around the fifteen sites chosen. Excess Lifetime Cancer has values ranging from 3.85 10-3 to 12.58 10-3 and 3.45 10-3 to 8.73 10-3. Risks were evaluated for the cobalt and the sixteen places inside the plant. The absorbed dose values at 5 m, 10 m, and 15 m inside the Co-60 bunker and the location Co-60 bunker as part of the facility exceeded the ICRP-recommended limit of 0.57. The AEDE and ELCR levels were within the ICRP's acceptable limits. The AEDE and ELCR statistics acquired indicate that the Cobalt-60 unit and its surroundings are radiation safe, although the likelihood of employees contracting cancer from the absorbed dose and background ionizing radiation is significant over a lifetime. Recommendation: However, it is recommended that absorbed dose level monitoring and evaluation of the Radiation Therapy Technologist (RTT) and other workers surrounding the unit be monitored on a regular basis. It is also recommended that Occupational Staff, such as RTTs, spend as little time as possible in the bunker  


2020 ◽  
Author(s):  
Manoj Kumar Jindal ◽  
Santosh Kumar Sar

Abstract The study aimed to find the impact of COVID-19 on values of Annual Effective Dose Equivalent of the natural Gamma dose rate from Balod, Durg and Bemetara districts of Chhattisgarh (India). COVID-19 is a severe problem for many countries and to control and prevent the spread of this problem implemented the lockdown approach in many countries, including India. In this lockdown situation, almost all people are staying at home for 24 hours. Due to the present status of COVID-19, the Indian government also fixed the 67 days lockdown and one day was already successfully done as Janta Curfew, which worked the same as a lockdown. The value of indoor gamma dose rates was reported higher in most places as compared to the outdoor gamma dose rate, but in this pandemic situation, occupancy factor values are not applicable as recommended by UNSCEAR for calculation of Annual Effective Dose Equivalent (AEDE). Therefore, the present study introduces the new equations, which can measure the extra AEDE value during the lockdown for adults, children and infants.


2020 ◽  
Author(s):  
Manoj Kumar Jindal ◽  
Santosh Kumar Sar

Abstract The study aimed to find the impact of COVID-19 on values of Annual Effective Dose Equivalent of the natural Gamma dose rate from Balod, Durg and Bemetara districts of Chhattisgarh (India). COVID-19 is a severe problem for many countries and to control and prevent the spread of this problem implemented the lockdown approach in many countries, including India. In this lockdown situation, almost all people are staying at home for 24 hours. Due to the present status of COVID-19, the Indian government also fixed the 67 days lockdown and one day was already successfully done as Janta Curfew, which worked the same as a lockdown. The value of indoor gamma dose rates was reported higher in most places as compared to the outdoor gamma dose rate, but in this pandemic situation, occupancy factor values are not applicable as recommended by UNSCEAR for calculation of Annual Effective Dose Equivalent (AEDE). Therefore, the present study introduces the new equations, which can measure the extra AEDE value during the lockdown for adults, children and infants.


Author(s):  
A. Ibitola, Gilbert ◽  
Ajanaku Olanrewaju ◽  
Ilori, Abiola Olawale ◽  
R. O. Aremu ◽  
I. A. A. Omosebi

The aim of this present study is to collect soil samples and some commonly consumed food materials in Ondo State, Nigeria such as tubers (cassava, Manihot esculent and yam, Dioscorea alata) samples and vegetables (waterleaf, Talinium triangulare and bitter leaf, Vernonia amygdalina) samples at some selected locations in Okitipupa, Ondo state, Southwestern, Nigeria in order to determine the following natural radionuclides (40K, 238U and 232Th) levels using a well calibrated NaI(TI) which is well shielded with a detector coupled to a computer resident quantum MCA2100R Multichannel. The transfer factors, annual absorbed dose rate and the annual effective dose in the samples collected were estimated. The results showed that the measured natural radionuclides were present in the mean concentrations of 323.79 ± 12.45 Bqkg-1, 81.87 ± 45.30 Bqkg-1 and 57.62 ± 18.04 Bqkg-1 for 40K; 11.76 ± 36.03 Bqkg-1, 4.67 ± 10.12 Bqkg-1 and 3.45 ± 2.10 Bqkg-1 for 238U and 9.66 ± 0.89 Bqkg-1, 3.07 ± 2.45 Bqkg-1  and 2.45 ± 0.92 Bqkg-1  for 232Th for soil, yam and cassava samples respectively. The results also showed that the radionuclides were present in the concentrations of 11.76 ± 36.03 Bqkg-1 and 9.66 ± 0.89 Bqkg-1 for 40K; 9.67 ± 8.53 Bqkg-1 and 7.87 ± 1.89 Bqkg-1 for 238U and 8.63 ± 6.08 Bqkg-1 and 6.58 ± 0.76 Bqkg-1 for 232Th for waterleaf and bitter leaf samples respectively. The soil-to-yam transfer factors were found to be 0.26, 0.40 and 0.32 for 40K, 238U and 232Th and soil-to-cassava yam transfer factors were found to be 0.18, 0.29 and 0.25 for 40K, 238U and 232Th respectively. The soil-to-waterleaf transfer factors were found to be 0.37, 0.82 and 0.82 for 40K, 238U and 232Th while the soil-to-bitter leaf transfer factors were found to be 0.32, 0.74 and 0.68 for 40K, 238U and 232Th respectively. The mean absorbed dose rate was 25.08 ± 0.57  and the mean annual outdoor effective dose was 46.17 . The annual effective dose reported for this present study area represents 65.95% of the world average value of 70.00 and 47.11% of Nigeria value of 98.00 mSvy-1  


2021 ◽  
Vol 8 (S1-Feb) ◽  
pp. 97-103
Author(s):  
Niranjan R S ◽  
Ningappa C ◽  
Nandakumar V ◽  
Harshavardhana C N

All individual living beings on the earth are exposed continuously to the radiations coming from terrestrial and extraterrestrial sources and also from their own bodies. The indoor and outdoor ambient gamma radiations are measured in and around Nuggihalli- Holenarasipura schist belts of Hassan district in Karnataka state. The measurements are carried out using the environment radiation dosimeter UR 705 which is a portable detector. Absorbed dose rate and annual effective dose rate are estimated by measuring the exposure rate. The total annual effective dose calculated from both indoor and outdoor varies from 0.68 to1.62 mSv.y-1 with an average value of 1.16 mSv.y-1. The calculated indoor and outdoor annual effective doses are found to be higher than the world average.


2013 ◽  
Vol 3 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Heiyam Najy Majeed ◽  
Ali . K. Hasan

Al-Najaf Al-Ashraf city on of the most important cities in Iraqi country it was chosen as the cultural Islamic capital for 2012 by the Islamic world ,Kufa university will be played big role of liability, cultural and education efficacies, this city had been exposed to artillery bombard expand along different areas in 1991 and 2003 in our research we try to test the studying area to know The total absorbed dose rate and the most possible hazards for this reasons the study was done. The natural radiation of thirty two samples of soil which collected randomly in June 2012 from the new Kufa University location were measured using Na(Tl) detection. The mean values activity concentrations of 238U, 232Th and 40K was (25.73±11.23 , 3.72±0.81 and 165.16±9.39 ) Bq kg-1 respectively . The highest value of the Radium equivalent activity was (30.870) Bq.kg–1 in (S2) which mean that all the soil samples values lower than (370Bq kg-1) the world average . External and internal hazard and gamma activity concentration (representative level index) indexes were lower than unity for all samples . The average value of absorbed dose rate calculated from activity concentration of 238U , 232Th and 40K was (20.553) nGy h-1 this value coincident to recommended. Annual effective dose in (?Sv/y) varies from (36.912) (?Sv/y) in (S15) to (15.460) (?Sv/y) in (S8) , all the soil samples have the annual effective dose less than the world average 460 (?Sv/y). The results can be consider as base values for distribution of natural radionuclides in the region and will be used as references information to assess any changed in the radioactive background level due to geological processes.


Author(s):  
S. S. Kerinja ◽  
U. Ibrahim ◽  
S. D. Yusuf ◽  
M. M. Idris ◽  
A. A. Mundi

In this study, the radiation exposure rate emanating from the scrap metals dumpsite was assessed using an Interceptor Spectroscopic personal radiation detector (SPRD). Sixteen (16) scrap metal dumpsites were selected at random across four Local Government Areas (Nasarawa, Lafia, Akwanga, and Keffi) of Nasarawa State, Nigeria. The gamma activity level in µrem/hr on three (3) randomly selected points on each of the scrap metal dumpsites was determined. A reading was taken on point 100 m away from each of the scrap metal dumpsite. Results show that the highest annual effective dose equivalent was observed in Akwanga (AKW4) scrap metal dumpsite with an annual effective dose equivalent of 0.2167 mSv/yr. The scrap metal dumpsite with the lowest annual effective dose equivalent was observed in Lafia (LAF3) and (LAF4) with an annual effective dose equivalent of 0.0613 mSv/yr. The excess lifetime cancer risk of 0.7585 × 10-3 was the highest value recorded in AKW4, while the lowest value was found to be 0.2146 × 10-3 in LAF3 and LAF4. The control radiation exposure level, 100 m from scrap metal dumpsites, shows the value of gamma activity level and annual effective dose equivalent obtained is ranged between 13 µrem/hr and 0.1594 mSv/yr respectively on location KEF1 to 3 µrem/hr and 0.0368 mSv/yr on locations LAF2 and LAF3 respectively. The annual effective dose equivalent values obtained were below the ICRP dose limit of 1 mSv/yr, indicating that, the environments around these scrap metal dumpsites are safe. The excess lifetime cancer risk value (ELCR) obtained in some locations is higher than the world average value of 0.29 × 10-3. Therefore, we recommend that scavengers, workers at the scrap dumpsites are to minimise the period of their stay within the dumpsites, and also the residential homes are to maintain a distance of 500 meters around the scrap metal dumpsites so as to minimise the risk of developing any health problem relating to cancer in future.


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