Annual Effective Dose Equivalent Research Articles

Radiological and environmental studies on the metamorphosed sandstones at Wadi Sikait area, southeastern desert, Egypt

Wadi Sikait area lies in the southern part of the Eastern Desert of Egypt along the upper stream of Wadi.Sikait. The exposed rock units in Wadi Sikait area are ophiolitic mélange roccks, metamorphosed sandstones, and porphyritic granites, lamprophyre dykes, in addition to fluorite and quartz veins. The activity concentrations of various radionuclides are measured by NaI-Tl activated detector and the radioactive mineralization were determined by Alpha track technique using CR-39 films. Radiometric investigations indicate that 238U activity concentrations range between 37.2 and 520.4 with average 148.8 BqKg−1, 232Th activity concentrations vary between 8.08 and 366.99 BqKg−1 with 76.75 BqKg−1 as an average. The studied metamorphosed sandstones have higher values relative the world concentration levels. High uranium content of the metamorphosed sandstone is attributed to presence radioactive minerals like uranophane and autonite, in addition to accessory minerals like allanite, zircon and monazite. Other U-bearing minerals are also recorded as biotite, muscovite, iron oxides and clays. Absorbed Dose Rate (D), annual effective dose equivalent (AEDE), radium equivalent activity (Raeq), external (Hex) and internal (Hin) hazard index, in addition to activity gamma index (Iγ) caused by gamma emitting natural radionuclide are determined from the obtained values of 226Ra, 232Th and 40K. Fairly, many of the studied metamorphosed sandstone do not satisfy the universal standards.

Radiometric mapping of terrestrial gamma radiation and evaluation of radiological health risk on the residents in Nigeria state commercial and capital cities

The radiometric mapping of the terrestrial ionizing radiation to evaluate the possible radiological health risk to residents of Agbor and Asaba metropolis have been conducted, using a digilert nuclear radiation monitor meter and geographical positioning system (GPS). The two monitored cities and environs were delineated into five zones. Measured zones mean outdoor background ionizing radiation (BIR) levels in Asaba ranged from 0.012 ± 0.003 mRh−1 (1.01 ± 0.27 mSvy−1 to 0.023 ± 0.009 mRh−1 (1.96 ± 0.82 mSvy−1) with total mean value of 0.018 ± 0.006 (1.52 ± 0.49 mSvy−1). In Agbor, zones mean outdoor BIR levels ranged from 0.012 ± 0.004 mRh−1 (1.01 ± 0.35 mSvy−1 to 0.019 ± 0.004 mRh−1 (1.58 ± 0.37 mSvy−1) with total mean value of 0.016 ± 0.004 (1.38 ± 0.38 mSvy−1). The mean outdoor absorbed dose rate for Asaba and Agbor are 158.34 ± 50.44 and 141.52 ± 29.58 respectively. The mean annual effective dose equivalent (AEDE) for the two cities are 0.19 ± 0.05 and 0.16 ± 0.05 mSvy−1, respectively, while the mean excess lifetime cancer risk (ELCR) are (0.69 ± 0.21 and 0.64 ± 0.17) × 10−3 mSvy−1, respectively. The estimated effective dosage to organs received shows that testes have the highest dose of 0.10 mSvy−1, with liver receiving the lowest dose of 0.06 mSvy−1. The study revealed that of the 100 sampling locations, 76 sampling sites outdoor radiation levels (76%) exceeded the World ambient standard levels of 0.013 mRh−1(1.0 mSvy−1). The overall results obtained shows elevation of BIR levels and all the estimated risk parameters except ELCR and effective doses to organs, above recommended limit for the public. However, these values obtained will not constitute any immediate radiological health risk to the residents of the study areas.

Assessment excess lifetime cancer risk of soils samples in Maysan neighborhood adjacent to the middle Euphrates cancer center in Najaf / Iraq

In this study, 30 samples of soils were taken from in Maysan neighborhood adjacent to the middle Euphrates cancer center in Najaf / Iraq, gamma-ray spectrometer system connected with the NaI detector was used to measure the specific activity of the (238U, 232Th, 40K) nuclei, the specific activity values were varied from(1.41±0.71Bq/kg) to (30.95±0.74 Bq/kg) with an average value(10.03± 1.04) for 226Ra, for 232Th from (0.71±0.27) to (15.44±0.30 Bq/kg) with an average value (4.96±0.37), The measurements of the specific activity of the 40K varied from 92.77±1.95 to 589.77±3.18 Bq/kg with an average value (198.43±3.13).Radium equivalent activity, outdoor and indoor absorbed doses, the Outdoor, Indoor and total annual effective dose equivalent (AEDE), external and internal hazard index (Hex, Hin) in the range of 32.415±1.817(Bq/kg), 16.104±0.827(nGy/h), 20.936±1.075(nGy/h), 0.019±0.001014(mSv/year),0.102±0.0052(mSv/year), 0.121±0.0061(mSv/year), 0.087±0.004, 0.114±0.007 respectively, Representative level index Iγr and excess lifetime cancer risk (ELCR), Representative Alpha index (Iα) and annual gonadal dose rate (AGDE) were calculated with range, 0.248±0.012(Bq kg-1), 0.423*10−3, 0.052(Bq/Kg), 119.404( mSv/y) respectively. These results were compared with recommended values (370 Bq/kg) for Raeq, 59 nGy/h for Dout, 84 nGy/h for Din,0.07 mSv/year for Deffout, 0.41 mSv/year for Deffin,0.48 mSv/year for Defftot, ≤1 for Hex and Hin, <1 for Iγr, <1 for Iα, 300 μSv/y for AGDE by UNSCEAR International Commission on Radiological Protection (ICRP) and European Commission (EC), and Their values were less than the permissible limits except for one sample out of 30 samples have specific activity values of 40K, Annual Gonadal Equivalent Dose (AGED) in sample (S6)higher than the worldwide average value (412 Bq/kg)and( 300 μSv/y) recommended by the UNSCAER, besides, the value of ELCR was lower than the world permissible value of 1.45×10−3 (UNSCEAR,2000). As a result, health hazards originated by natural radiation from soil samples in this region is low and insignificant.

Determination of natural radioactivity levels and radiological hazards in environmental samples from artisanal mining sites of Anka, North-West Nigeria

Artisanal mining of precious metals has become a lucrative venture in Anka, Zamfara State, North-West Nigeria. The use of crude methods of mining and mineral processing and the apparent ignorance of the hazards involved have been linked to some health and environmental consequences. Hence, this study focuses on the assessment of radioactivity levels in rock, soil and sediment samples as well as the radiological hazards of the artisanal mining in Anka. The gamma-ray spectrometry method was employed in the sample analysis. The results show that the estimated mean activity concentrations of 226Ra, 238U, 232Th and 40K in soil were 37.94 ± 6.01 Bqkg−1, 41.60 ± 11.06 Bqkg−1,151.15 ± 21.09 Bqkg−1 and 380.34 ± 116.41 Bqkg−1, respectively. The activity concentrations in rocks and sediments were also analyzed. The radioactivity levels were highest in rock samples. ; For rock samples, mean radium equivalent was 499.18 Bqkg−1, gamma dose rate was 221 ± 35 nGyh−1, internal and external hazard indices were 1.35 and 1.53, respectively and the radioactivity level index was 3.24. The outdoor and indoor annual effective dose equivalents were 271.03 µSvy−1 and 985.39 µSvy−1, respectively. The mean indoor and outdoor excess lifetime cancer risk for soil were 0.55 × 10−3 and 2.18 × 10−3. The evaluation of radiological health risks shows that the values obtained in this study were generally higher than admissible recommended limits and the world averages. The results obtained in this study show that the risk of exposure to ionizing radiation is linked to the artisanal mining and mineral processing in Anka.

On the 30th anniversary of the Chernobyl Nuclear Power Plant Accident, assessment of the activity concentrations and the radiological hazard parameters of soil samples collected from Rize province and districts

Uranium, thorium and potassium are the main terrestrial sources of radiation that are located at different levels in the soil depending on the geographical and geological conditions and contribute to increase of the natural radiation levels of the regions. In addition to the natural radiation sources, Cesium-137 which can spread from nuclear tests and accidents such as Chernobyl Nuclear Power Plant Accident is also an important artificial radiation source of that contributes to the increase of radioactivity in the soil. Determination of both natural and artificial radioactivity levels of soil is important in terms of assessing people's possible exposure to the internal radiation and ensuring that people can be protected from the harmful effects of the external radiation. In this study, on the 30th anniversary of the Chernobyl Nuclear Power Plant Accident, soil samples were collected from Rize province which was affected by the Chernobyl Nuclear Power Plant Accident in 1986 and the activity concentrations of natural and artificial radionuclides were measured and radiological hazard parameters were calculated. Radioactivity measurements were caried out with gamma spectrometry system with a high purity germanium detector. The activity concentrations were measured in range of 4.45 ± 0.39 to 32.19 ± 0.78 Bq kg−1 with an average of 17.68 ± 0.68 Bq kg−1 for 226Ra, 5.58 ± 0.65 to 43.61 ± 1.67 Bq kg−1 with an average of 22.53 ± 1.26 Bq kg−1 for 232Th, 28.82 ± 1.37 to 773.19 ± 12.14 Bq kg−1 with an average of 277.14 ± 6.24 Bq kg−1 for 40K and 1.99 ± 0.17 to 376.85 ± 2.52 Bq kg−1 with an average of 110.11 ± 0.98 Bq kg−1. The average activity concentrations of 226Ra, 232Th and 40K were found below the world median activity concentrations of 35, 30 and 400 Bq kg−1, respectively. Despite the high 137Cs activity concentrations were determined in present study compared to similar works being done in Turkey and other countries, the average activity concentration of 137Cs in investigated samples was significantly found lower than the 137Cs values in soil samples from Rize in 1990 carried out by TAEA. In present study, the average radium equivalent activity (Raeq), external hazard index (Hex) and internal hazard index (Hin) values were below the recommended limits by UNSCEAR. The average absorbed dose rate in air (D) and annual effective dose equivalent (AEDE) values were found lower than the world median values. The calculated excess lifetime cancer risk (ELCR) values for soil samples were obtained less than the precautionary limit of 0.29 × 10−3.

Impact of lockdown during COVID-19 pandemic on annual effective dose equivalent values of natural gamma radiation.

The study aimed to determine the impact of COVID-19 on values of annual effective dose equivalent of the natural gamma dose rate of 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, the lockdown approach has been implemented in many countries, including India. In this lockdown situation, almost all people stay at home for 24 h. 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 to be higher in most places 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 lockdown for adults, children and infants.

Radiological safety of groundwater around a uranium mine in Namibia

Uranium mining activities produce the main element used in nuclear energy production. However, it can also negatively affect the environment including groundwater by release of residues or effluent containing radioactive elements. The study investigated the concentration and radiological hazard of uranium in groundwater and seepage water from the tailings of a uranium mine in Namibia. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to assess the concentration of uranium in the groundwater and seepage water and the radiological hazards were determined. The radiological hazard indices Radium equivalent activity (Raeq), Absorbed dose (D), Annual Effective Dose equivalent (AEDE), External hazard index (Hex) and Internal hazard index (Hin) were determined and compared to limits recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The calculated average value of D and Hin of groundwater is 108.11nGyh−1 and 1.26, respectively and are above the UNSCEAR values (55 nGyh−1 and 1). Further, the average values of Raeq, AEDE and Hex were below the recommended values. The isotopic ratio of uranium radionuclides in groundwater indicates that the uranium in the sampled groundwater is below 1 suggesting it is not natural uranium present but a possible contamination from the mine seepage. The radiological hazard parameters of the seepage water were above the recommended values and thus pose a radiation risk to human and environment.

Environmental radioactivity of groundwater and sediments in the Kuiseb and Okavango-Omatako basins in Namibia

Naturally occurring radionuclides of terrestial origin are ubiquitously present in the environment including groundwater and sediments and their concentrations vary depending on the geology and hence the type of soil. The objective of this study was to evaluate the radioactivity levels and health risk due to radionuclides in ground water and sediments samples collected from Kuiseb and Okavango-Omatako river basins in Namibia. The activity concentrations of radionuclides in groundwater and sediments were measured by a high purity germanium detector and PM1406 Food monitor. The activity concentrations of 238U, 232Th and 40K in sediment samples varied from 7 ± 0.001 Bq.kg−1 to 46 ± 0.001 Bq.kg−1, 8 ± 0.001 Bq.kg−1 to 70 ± 0.002 Bq.kg−1 and 345 ± 0.010 Bq.kg−1 to 776 ± 0.026 Bq.kg−1 respectively. To assess the radiological hazard of radioactivity present in the sediment samples, the absorbed dose (D), the annual effective dose equivalent (AEDE), Radium equivalent (Raeq) and external hazards (Hex) were calculated and these varied from 25.19 to 82.55 nGyh−1, 0.03 to 0.10 mSvy−1, 51.30 to 181.21 Bqkg−1 and 0.14 to 0.49 respectively. Similarly, the mass elemental concentration in all sediment samples collected from the two water basins ranged from 1 ± 0.001 to 4 ± 0.001 mg kg−1 for 238U, 2 ± 0.003 to 17 ± 0.002 mg kg−1 for 232Th and 1 ± 0.001 to 3 ± 0.026% for 40K while the activity concentrations in groundwater samples of 40K were below the detectable limits (BDL) for the two water basins. The Raeq values for sediment samples were lower than 370 Bqkg−1 which is equivalent to a gamma dose rate of 1.0 mSvy−1 - the dose prescribed by International Commission on Radiological Protection (ICRP) for members of the public and thus the use of sediments for construction purposes does not constitute any radiological health hazard to the general population in these areas.

Determination of Natural Radionuclides and Mineral Contents in Environmental Soil Samples

A study of natural radioactivity levels in environmental samples within the northern coastal region of Egypt and the Eastern Province—Khobar, Dammam, Saudi Arabia, has been evaluated. The samples were analyzed using gamma spectrometry based on HpGe detector. The mean activity concentrations of 238U, 232Th, 235U, 40K in addition to 137Cs were 27.03 ± 6.74 Bq/kg, 19.76 ± 0.92 Bq/kg, 0.83 ± 0.06 Bq/kg, 147.11 ± 1.69 Bq/kg and 0.09 ± 0.01 Bq/kg for the first region and 32.9 ± 6.65 Bq/kg, 28.2 ± 0.78 Bq/kg, 1.10 ± 0.3 Bq/kg, 193.8 ± 1.55 Bq/kg and 0.1 ± 0.001 Bq/kg for the second region, respectively. The radiological hazard parameters such as the absorbed dose rate (D), annual effective dose equivalent (AEDE), gamma-ray hazard index (Iγ) and the annual gonadal dose equivalent of the studied samples were estimated. Also, the current work provided the mineralogical composition and the correlations between them and the distribution of radionuclides.

Assessment of Environmental Radioactivity Level and its Health Implication in Imiringi Community Bayelsa State, Nigeria

A total forty two (42) sampled points were investigated for radioactivity level and health implication using standard method. The exposure dose rate ranged from 14 to 32μRh-1 with an average value of μ23Rh-1. Dose rate and equivalent dose rate ranged from 121.8 to 278.4nGyh-1 and 1.18 to 2.69mSvy-1 respectively. The average value of the indoor annual effective dose equivalent (AEDE), outdoor AEDE, and excess lifetime cancer risk (ELCR) were computed to be 0.936 mSvy-1, 0.311 mSvy-1 and 0.810 x 10-3 respectively. Analysis of dose to human organs; testes and ovaries, were 0.61 and 0.43 mSvy-1 respectively. Exposure rate, dose rate and ELCR exceeded the recommended values. All the outdoor AEDEs were within the permissible value of 1.0 mSvy-1 for general public and below the limit of 20 mSvy-1 for radiological workers as recommended by InternationalCommission on Radiation Protection (ICRP).&#x0D; Keywords: Assessment, Environmental radioactivity, Exposure dose, Health impact

EFFECTS OF LOCAL BUILDING MATERIALS ON INDOOR GAMMA DOSES AND RELATED RADIOLOGICAL HEALTH RISKS, AYVACIK, ÇANAKKALE/TURKEY.

In situ indoor gamma dose rate measurements were held in 79 dwellings by NaI(Tl) scintillation probe connected portable dose rate meter. For the building materials and impurities (nodules), spectrometric gamma analysis was applied by a high-resolution HpGe detector. For Ahmetçe and Nusratlı villages in Ayvacik/Çanakkale (Turkey), the measured in situ indoor gamma dose rates and related indoor annual effective dose equivalents (AEDEin) were 3 and 3.3 times, and indoor excess lifetime cancer risks (ELCRin) were 4.25 and 4.68 times higher than those of the world averages, respectively. The used local rocks were mostly ignimbrite and dacitic-rhyolitic tuffaceous (Arıklı tuff), and wall plasters were made of local soil. The highest in situ indoor gamma dose rates of the region belonged to Nusratlı village due to the intense impurities (nodules) and hydrothermal alterations in Arıklı tuff. Spectrometric gamma results revealed that 40K has an important effect on the indoor gamma doses.

Spatial distribution, risk assessment and influence factors of terrestrial gamma radiation dose in China

The current spatial distribution of the risk of terrestrial gamma radiation in China were investigated by using spatial interpolation. And the driving factors influence on the terrestrial gamma radiation dose (TGRD) distribution were identified using the geographic detector, a new statistical method based on the nonlinear hypothesis. The results showed that the values of TGRD were range from 60 to 195 nGy h−1 with the average of 86.5 nGy h−1, and the higher values were recorded in Qingahi–Tibet Plateau, which were all within the range of background value in China. In addition, the radiological indices, ELCR (Excess Lifetime Cancer Risk), TGRD and AEDE (Annual Effective Dose Equivalent) were also within the acceptable range of values by risk assessment. The results by use of the geographic detector showed that sunshine duration, atmosphere pressure, altitude, and rainfall condition have closely related to the TGRD distribution. In addition, these meteorological factors and altitude had more impact on TGRD than the air pollution-related factors. Our study can provide useful information on studying the influence mechanism of the TGRD distribution, the variability of the natural terrestrial gamma radiation in China, and exposure data for risk assessment from low dose chronic exposures.

Reforestation and soil recovery in a Mediterranean mountain environment: Insights into historical geomorphic and vegetation dynamics in the Sila Massif, Calabria, southern Italy

We investigated the genesis and local response of soils in mountain sites of the Sila Massif (Calabria, southern Italy), reforested ca. 60 years ago, and their relationships with geomorphic dynamics and forest stand structure. A multidisciplinary approach is proposed, focused on an often neglected soil profile scale and horizon-wise sampling strategy, and including pedological field observations, physical, chemical, mineralogical analyses, isotope geochemistry including fallout radionuclides (137Cs and 210Pbex), geomorphology, historical documentation of anthropogenic land cover changes, forestry and dendrometric measurements. Reforestation was carried out following extreme land degradation, which took place after forest clearance and field cultivation. Different tree species and soil preparation techniques were used according to site conditions. We focused on the main properties of selected soil profiles and the distribution of some radionuclides, in order to understand the effects of forest stands on hampering soil erosion and promoting novel soil formation, and to evaluate the potential hazard of natural gamma radiation. A comparison with soil profiles developed under naturally regenerated forest and field crops was achieved. The soil profiles in reforested sites showed a poor degree of development and a complex history of reworking processes alternated with soil-formation processes, in line with modern to historical radiocarbon dates increasing downprofile, the presence of buried horizons and 137Cs in the topsoils. Inventory changes obtained for 210Pbex and 137Cs highlight a process of soil stabilization occurred after reforestation, with more efficient effects under Calabrian pine than oak forest, whereas major geomorphic dynamics (erosion and accumulation) were triggered by forest coppicing, thinning and agricultural practices. Our data remark a positive response of the soil ecosystem to reforestation against erosion, trapping mobile material, stabilizing buried soils, promoting humus accumulation leading to new shallow topsoils, and the protective role of forests against anthropogenic and climatic-induced threats. Average values of the annual outdoor effective dose equivalents of gamma-emitting radionuclides calculated for all the soil horizons showed lower values than the population-weighted world’s average, with the exception of the soil profiles under forest stands developed on granite, exceeding this threshold. A deeper comprehension of soil genesis, geomorphic processes, land use and vegetation dynamics in vulnerable ecosystems such as mountain environments represents a fundamental basis for sustainable land management policies.

Assessment of Radiation Exposure Level from Some Scrap Metal Dumpsites in Nasarawa State, Nigeria

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.

Investigation of Outdoor Gamma Dose Rates in Yalova, Turkey

Radioactivity measurements were performed, at the Yalova (Turkey), part of the Marmara Sea, for natural radiation using a scintillation detector SP6 (via using portable counter ESP2, Eberline). Based on the measurement results, the lowest outdoor gamma concentration was calculated to 27.70 nGy/h while the highest one calculated to 66.00 nGy/h. And, the average of the measured gamma dose rates calculated to 48.13 nGy/h while the annual effective dose equivalent was calculated to 59.02 μSv/y. Mean value of excess lifetime cancer risk also obtained 2.07 10-4 from using measurement area. The results checked against the world average determined by UNSCEAR. It was concluded that the calculated gamma dose values in Yalova are below the world average.

Assessment of background nuclear radiation and its health implications in selected cities of Ondo State, Nigeria

This research explores the measurement of background nuclear radiation, rate of exposure and the radiological risk for the inhabitants of South-western Nigeria. The measurement was carried out using Rad*Scanner model 500VBR, which measures radiation dose in count per minute. The mean absorbed dose rate ranges between 147.26 ± 8.13 nGy h−1 and 228.20 ± 20 nGy h−1, the annual and collective annual outdoor effective dose equivalent, with collective health detriment were estimated using the obtained data. The mean annual outdoor effective dose equivalent was estimated at 268.37 ± 38.25 µSv y−1. This value is below 1 mSv y−1 limit recommended by ICRP but greater than 0.1 mSv y−1 recommended by WHO. Using a population of 3,441,024, the mean collective effective dose equivalent was estimated at 923.46 ± 131.619 Man-Sv y−1. The collective health detriment was estimated to be approximately 15 men which could vary depending on hours of exposure.

Assessment of indoor and outdoor radiation levels and human health risk in Sheda Science and Technology Complex and its environ, Abuja, Nigeria

A study to assess the Indoor and Outdoor Background Ionizing Radiation (BIR) of Sheda Science and Technology Complex, Abuja has been conducted. An in-situ measurement using a portable factory calibrated radiation dose rate meter, Radiagem 2000, was used to ascertain the radiation level. The measured radiation dose rates were used to evaluate the radiological health hazards and radiation effective doses to different body organs using well established radiological relations. The results shows that the total Dose Rate (indoor and outdoor), the Total Annual Equivalent Dose (indoor and outdoor), total Annual Effective Dose Equivalent (indoor and outdoor) and the total Excess Lifetime Cancer Risk (indoor and outdoor) are 0.113±0.022 (μSv/h), 0.071±0.016 (μSv/h), 0.794±0.155 mSv/y, 0.0.124±0.074 mSv/y, 0.556±0.109 mSv/y, 0.087±0.020 mSv/y, 1.945±0.379, 0.304±0.104 respectively for the three zones. The dosage to organs received shows that the testes have the highest dose while the liver has the lowest dose (indoor and outdoor) for the three zones. Generally the study shows that the Annual Effective Dose Equivalents were within the permissible limits of 1 mSv/y for general public exposure recommended by the (ICRP). Also, the effective doses to different body organs are all below the recommended limits of 1 mSv/y. The calculated Excess Lifetime Cancer Risk values indicates that the chance of contacting cancer by workers and residents of the study area is not probable hence the study area could be said to be radiologically safe. Keywords: Ionizing Radiation, Equivalent Dose, Effective Dose, Excess Lifetime Cancer Risk

Measurement of natural radioactivity in river sediments of Thamirabarani, Tamilnadu, India using gamma ray spectroscopic technique

ABSTRACT Natural radioactivity is diffuse in earth’s environment and occurs in various geological formations like sand, soil and rocks as well as in plants, water and air. Among the various building materials, river sediment is commonly used in building constructions. Sediment samples were collected from Thamirabarani river belt, Tamilnadu, India. Radiometric analysis was carried out using Gamma ray spectrometry for the sediment samples in this area. Activity concentrations of the natural radionuclides such as 226Ra, 232Th and 40K were determined and other radiological parameters were calculated. The average activity concentration values for 226Ra, 232Th and 40K were 40.85, 51.87 and 838.19 Bq kg−1, respectively. Radium equivalent (Raeq), absorbed dose rate (DR), annual effective dose equivalent (AEDE), hazard indices (Hex and Hin) and activity utilisation index (AUI) were also calculated and compared with world average values. The mean values of the radiological parameters are less than the recommended limit. Hence, there is no radiological hazard involved in using river sediments for construction from in this study area.

Assessment of Radionuclide Concentration in Surface Soil and Human Health Risk Associated with Exposure in Two Higher Institutions of Esan land, Edo State, Nigeria

The aim of this study is to assess the activity concentration of radionuclides and the possible health risk associated with exposure to radiation from the soil samples collected from two higher institutions in Esan land of Edo State, Nigeria. The gamma spectrometry system was used to determine the activity concentrations of radionuclides 238U, 232Th and 40K in the surface soil samples. The activity concentration of radionuclides ranged from 7.16 ± 0.63 to 102.37 ± 2.37 BqKg-1for 40K, from 0.75 ± 0.05 to 3.13 ± 0.11 BqKg-1 for 238U and from 2.25 ± 0.20 to 9.02 ± 0.40 BqKg-1for 232Th. The measured mean activity concentration of radionuclides for 40K, 238U and 232Th from the examined topsoil of Samuel Adegboyega University were 57.80 ± 1.7 BqKg-1; 2.07 ± 0.09 BqKg-1 and 6.89 ± 0.34 BqKg-1 respectively. At the neighbouring higher institution; College of Education, Igueben, the mean activity concentration of 40K, 238U and 232Th in its surface soil were 30.19 ± 1.22 BqKg-1, 1.41 ± 0.07 BqKg-1 and 4.85 ± 0.28 BqKg-1 respectively. The total mean values for radiation dose estimation for Radium Equivalent Activity, Absorbed Dose, Excess Lifetime Cancer Risk, Outdoor and Indoor Annual Effective Dose Equivalent are 13.20 BqKg-1, 6.03 nGy/ℎ, 0.026, 7.40 µSτ/γ and 29.60 µSτ/γ respectively. These values were found to be lower than the global average values. Hence, there is no radiation induced health threat to the students and members of staff in the study area.Keywords: Soil, exposure, health risk, activity concentrations

AT HIGH BACKGROUND RADIATION AREAS THE RELATIONSHIP BETWEEN IN SITU INDOOR GAMMA DOSE RATES AND BUILDING MATERIALS: A CASE STUDY FROM ARIKLI VILLAGE (AYVACIK/ÇANAKKALE/TURKEY).

This study measured in situ indoor gamma dose rates in Arıklı village situated near a uranium mineralisation region, evaluated the risks of radiological health hazards and established a hypothetical relationship between these values and building materials using statistical tools. Eberline brand portable type ESP-2 model Na (I) scintillation probe connected detector was used for the measurements in 45 dwellings. Statistics revealed two groups. The first group consists of the dwellings made of bricks or mixed materials both plastered by cement, while the second group represented the dwellings made of Arıklı tuff plastered with soil (modified Arıklı tuff) or cement. For the first and second groups, respectively, the medians of the indoor gamma dose rates were 188.79 and 261.87 nGy/h; for indoor Annual Effective Dose Equivalents (AEDEin) they were 0.93 and 1.28mSv/h; and for Excess Lifetime Cancer Risks (ELCRin) they were 3.69 and 5.12, respectively. All the values were higher than those of the world averages.