Mean Activity Concentrations Of 226Ra Research Articles

Activity Concentration of Natural Radionuclides in Surface Sediments of Major River Watersheds in Korea and Assessment of Radiological Hazards

The assessment of potential radiation hazards in accumulated sediments in aquatic ecosystems is vital for the management and disposal of sediments. Furthermore, preemptive management of radionuclides in terrestrial ecosystems is critical for marine ecosystem conservation. We analyzed the activity concentrations of natural radionuclides (226Ra,232Th, 238U, and 40K) in the surface sediments of major river watersheds in Korea and evaluated the radiation hazards stemming from these activity concentrations. The mean activity concentrations of 226Ra and 238U were lower than the global average, whereas those of 232Th and 40K were higher. The mean values of radium equivalent activity, external hazard index, and internal hazard index calculated from these activity concentrations did not exceed the recommended maximum values. The mean values of absorbed gamma dose rate in air and annual outdoor effective dose rate (AEDRout) were higher than the global average by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) but remarkably lower than the recommended and background values by the International Commission on Radiological Protection (ICRP) and the Korea Institute of Nuclear Safety (KINS). The contribution of 40K and 232Th to the AEDRout mean value was predominant. In conclusion, the surface sediments of major river watersheds in Korea are associated with negligible radiation hazards. These findings provide fundamental data for the management and treatment of sediments in terrestrial and marine ecosystems.

Assessment of radiological contamination due to gold mining in soil and food crops of Babban Tsauni, Gwagwalada, Nigeria.

This work assessed the activity concentrations of 238U(226Ra), 232Th, and 40K and their associated radiological risks due to exposure to soil and consumption of food crops in Babban Tsauni artisanal gold mine, Gwagwalada, Nigeria, using the gamma spectrometry technique. The mean activity concentrations of 226Ra, 232Th, and 40K in the mine soil were 60.2±9.9, 161.4±16.2, and 664.6±138.2, while they were 46.4±4.9, 79.9±39.3, 266.4±185.4 for tubers and 46.9±15.7, 100.5±35.8, 311.4±132.7 (Bq/kg) for grains, respectively. The results reveal that the activity concentrations of radionuclides in all samples exceeded the recommended values set by United Nations Scientific Committee on the Effects of Atomic Radiation (33, 45, and 420 Bq/kg) except 40K, which fell within the acceptable limit in all food crop sample types. Estimated results for radiological hazard parameters, radium equivalent, annual effective dose due to ingestion, and excess life cancer risk were within safe limits, while the annual effective dose due to external gamma radiation in soil and annual gonadal equivalent dose were significantly high in all investigated samples; these call for constant radiological monitoring.

Determination of Natural Radioactivity Levels and Radiation Hazards from the Soil of Tin Mining in Kyerwa District, Tanzania

Gamma spectrometry was used to determine the activity concentrations of the natural radionuclides 226Ra, 232Th, and 40K in soil samples from the Tin mining in Kyerwa District, Tanzania. The study findings revealed that the mean activity concentrations of 226Ra, 232Th, and 40K were 90.68, 65.45, and 630.95 Bq/kg, respectively. These values were all greater than the average global activity concentrations for 226Ra, 232Th, and 40K which are 32 Bq/kg, 45 Bq/kg, and 420 Bq/kg, respectively. Assessments of the radiological risks associated with these naturally occurring radionuclides were done. In this case, the radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), and radioactivity level index (Iγ) were calculated. The results show that the mean values of Raeq, Hex, Hin, and Iγ were 230.6 Bq/kg, 0.628, 0.861, and 0.831, respectively. These results were below the global criteria levels for Raeq, Hex, Hin, and Iγ, which are 370 Bq/kg, 1, 1, and 2, respectively. Estimates for the absorbed dose rate in the air (DR), the annual effective dose equivalent (AEDE), and the annual gonadal equivalent dose (AGED) were also made. The findings revealed that the corresponding mean values for DR, AEDE, and AGED were 106.8 nGy/h, 1.07 mSv/y, and 744.4 μSvy-1. The mean values exceeded the global average value of 57 nGy/h for DR, 0.07 mSv/y for AEDE, and 2984 Sv/y for AGED. Therefore, Tin mining activities in the Kyerwa District could endanger the mining community from natural radioactive sources. In this study, therefore, we recommend performing a periodic inspection of the mining areas, monitoring the mining workers, and determining the level of activity and concentrations of different radionuclides in the mining area.

Natural radioactivity in food crops and soil and estimation of the concomitant dose from tin mining areas in Nigeria

Mining of mineral ore is considered one of the anthropogenic sources of elevating the activity concentrations of the natural radionuclides in the environment, which in turn causes an increased risk of human exposure via the food chain. In an attempt to evaluate the radiological burdens resulting from tin mining activities in Nigeria, farm soil and sixty-two samples of different food crops grown around tin mining areas were evaluated for the activity concentrations of 226Ra, 232Th, and 40K using a high-purity germanium detector. The mean activity concentrations of 226Ra, 232Th and 40K in soil were 64.6 ± 29.5, 72.03 ± 28.73 and 680.6 ± 324.3 Bq/kg, respectively. These values were found to be higher than their corresponding world average values. However, the mean activity concentrations of the measured radionuclides in plants were below their respective world average values, as reported by UNSCEAR. The overall average annual ingestion dose due to the consumption of the analysed plants was 151 µSv/y, which is below the reported world average value of 290 µSv/y. The results obtained show that the hazard indices were low enough to cause any immediate radiological health complications due to the ingestion of the crops grown in the studied areas.

Standard addition method for the rapid analysis of 226Ra, gross alpha–beta and total radium isotope activities in surface water of Maritsa River, Türkiye

This research aimed to determine the activity concentration of 226Ra in the natural radioactivity of the surface water of the Maritsa River, Türkiye. The gamma spectrometric analysis was conducted by using 3′′ × 3′′ NaI(Tl) and (HPGe) detector. Since the direct measurement method could not acquire reliable results, the mean activity concentration of 226Ra was calculated as 0.62 Bq L−1 with the “standard addition method”. The mean values of the gross alpha/beta activities and the total radium alpha activity concentration were measured. The results are 0.013 Bq L−1, 0.304 Bq L−1, and 0.014 Bq L−1 respectively.

Radiometric and health risk assessment of building materials collected from Tamil Nadu using gamma-ray spectrometry

ABSTRACT The radiometric analysis was carried out on different building materials collected from Tamil Nadu, using gamma-ray spectroscopy with NaI(Tl) detector. The mean activity concentrations of 226Ra (38 Bq kg−1) and 40K (643 Bq kg−1) in all building materials were higher than the world-populated weighted average of 33 Bq kg−1 and 420 Bq kg−1, respectively, while for 232Th (28 Bq kg−1), it was lower than 45 Bq kg−1, as reported by UNSCEAR (2000). These results were compared with similar studies carried out around the world. The calculated radiological parameters, radium equivalent activity (127 ± 11 Bq kg−1), absorbed dose rate (61 ± 5 nGy h−1), annual effective dose equivalent (0.30 ± 0.02 mSv y−1), internal and external hazard index (0.45 ± 0.04 and 0.34 ± 0.03) and activity utilisation index (0.74 ± 0.08), are within the world-populated weighted average and safest limits. Moreover, the radiogenic heat production rate (RHP) due to the natural radionuclides in the building materials was calculated, and the total RHP was 0.94 µWm−3. Multivariate statistical analyses, such as Pearson correlation analysis, hierarchical cluster analysis and factor analysis, were implemented on activity concentration and radiological parameters to evaluate the interrelationship between them.

Assessing the radiological hazards due to radionuclides in sediments and tailings around Kilembe copper mines, Western Uganda

ABSTRACT Copper mining in Kilembe Valley, Western Uganda, between 1956 and 1982 resulted in multiple tailing sites, raising concerns about potential increases in the natural background radiation. In this study, the radioactivity concentrations of 226Ra, 232Th, and 40K in 31 sediments and tailing samples from the Kilembe copper mines area were determined using HPGe-based gamma spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K in sediment samples were 38.6 ± 8.9, 37.4 ± 7.8, and 708.0 ± 147.3 Bq kg−1, respectively. While in tailing samples, the mean values were 171.3 ± 31.7, 34.8 ± 14.9, and 792.4 ± 208.2 Bq kg−1, respectively. These values exceeded global averages of 35, 30, and 400 Bq kg−1 for 226Ra, 232Th, and 40K, respectively. To assess the radiological hazards due to radionuclides in sediments and tailings, several parameters such as the radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), gamma representative index (Iγ), absorbed dose rate (D), total annual effective dose (Etot), and total excess lifetime cancer risk (ELCRtot) were determined. In sediments, most of these hazard parameters were above the world’s average values, except Raeq, Iγ, Hex, and Hin. While in tailings, all the hazard parameters surpassed the global average values except Raeq and Hex. Pearson correlation coefficient and hierarchical cluster analysis showed that 226Ra was the main contributor to the assessed radiological hazards. The study suggests potential radiological risks linked to natural radioactivity from sediments and mine tailings, especially when used as building materials.

Natural radionuclides and radiological risk assessment in the stream and river sediments of a high background natural radiation area Kanyakumari, India.

The Kanyakumari coast is known to be a high background natural radiation area due to the placer deposits of heavy minerals such as ilmenite, monazite, and rutile. The Kanyakumari river sediments that could be the source of the elevated amounts of natural radionuclides in the coastal sands have been studied in this paper. The activity concentrations of primordial radionuclides 226Ra, 232Th, and 40K were determined using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 75Bqkg-1, 565Bqkg-1, and 360Bqkg-1, respectively. The mean absorbed dose rate was 395 nGy h-1. Radiological hazard parameters were studied and compared with the world average values. The contribution of 232Th to the total dose rate was found to be higher than that of the two other radionuclides. The high mean ratio of 232Th/226Ra suggested an enrichment of 232Th and the occurrence of 226Ra leaching due to an oxidizing environment. Principal component analysis (PCA) was carried out for the radionuclides in order to discriminate the source of the sediments. This study provides new insights into the distribution of natural radionuclides in sediments of rivers and streams.

A Study on Determination of Natural Radionuclide Concentrations in Tap Water Samples Collected from the Districts of Sinop Province, Türkiye

Since Turkey's second nuclear power plant is planned to be built in Sinop province, it is very important to determine the background levels of radioactivity in this region. In the present study, activity concentrations of 226Ra, 232Th and 40K natural radionuclides in nine tap water samples collected from the districts of Sinop province located in the north of Turkey were determined using a high purity germanium detector (HPGe). The coordinates of sampling areas were also recorded by GPS device (Magellan Explorist 510). The mean activity concentrations of 226Ra, 232Th and 40K radionuclides in the studied waters were calculated to be 1.74 ± 0.49 Bq/L, 1.39 ± 0.35 Bq/L and 5.32 ± 1.41 Bq/L. In addition, annual effective dose equivalents from the intake of these radionuclides in the tap water samples were calculated for infants, children and adults and the found results were compared with the values recommended by international organizations. As a result, there is no risk in terms of natural radioactivity in the consumption of studied waters by humans.

Assessment of Background and Soil Dumpsites Radioactivity in Plateau State, Nigeria

Assessment of background and dumpsites radioactivity level plays a significant role in the protection of man from excessive radiation exposure. Exposure to high radiation levels causes a wide range of health problems such as cancer of the lung, bone and skin, kidney ailments and blood infections. The background radiation levels of 51 selected dumpsites (3 in each LGA) were obtained at 1m above it using a well-calibrated International Medcom CRM-100 Digital Radiation Monitor. Soil samples were also collected, packed, prepared and analysed with Gamma ray Spectrometer [NaI (Tl) detector]. The mean activity concentrations of 226Ra, 232Th and 40K in this study are 61.93±5.90Bq kg-1,123.37±34.05 Bq kg-1 and 276.54±62.44 Bq kg-1 respectively. The mean absorbed dose, AEDE (outdoor) and ELCR in the state have the value of 111 nGyh-1, 0.13 mSv/hr and 0.45 x 10-3 respectively, which are greater than the world average value of 58 nGy h-1, 0.07 mSv/hr and 0.29 x 10-3 respectively. The mean background radiation of the dumpsites recorded in Plateau State was 204 nGy h-1 with the outdoor AEDE of 0.25 mSv/yr and ELCR of 0.88 x 10-3 . These values are greater than the world average. The results obtained for the background radiation are higher than those from the radionuclides analysis. The study revealed that the health risks associated with the radionuclide concentrations of soil dumpsites and the background radiation are relatively high, and the use of dumps as manure and other re-cycling processes therefore raises radiological concern.

Distribution of naturally occurring radionuclides and gamma dose rate assessment in the soils of high background natural radiation area Odisha, India.

A study on the activity concentration of primordial radionuclides 226Ra, 232Th and 40K was carried out on the surface soil samples collected from the coastal villages between Chhatrapur and Gopalpur regions of high background natural radiation area Odisha, India, using high purity germanium gamma spectroscopy. The mean activity concentrations of 226Ra, 232Th and 40K were found to be 231, 1692 and 250Bq/kg, respectively. The total mean absorbed dose owing to the presence of 226Ra, 232Th and 40K was 1139nGy/h. The mean annual effective dose was found to be 1397μSv/y and higher than the UNSCEAR average value 70μSv/y.

Distribution and impacts of contamination by natural and artificial radionuclides in attic dust and urban soil samples from a former industrial Hungarian city: A case study from Salgótarján

Primordial radionuclides can be found in all environmental compartments. Since coal-fired power plants (CFPP) can be a source of additional radionuclide contamination because coal contains natural radioactive isotopes such as 238U (226Ra) and 232Th. This study investigated the impact of such possible radionuclide contamination from former heavy industrial activities, namely a former local coal-fired power plant, in urban soils and attic dust in Salgótarján, Hungary. Even today, industrial by-products, e.g., coal ash, in this city represent significant threat to its residents. A total of 36 attic dust samples (family houses, kindergartens, churches and blockhouses) were collected and 19 urban soil samples (playgrounds, kindergartens, parks and others) were selected no further than 500 m from the corresponding attic dust sampling sites. Additionally, a coal ash and a brown forest soil sample were also collected to differentiate between the anthropogenic and geogenic sources in the residential area. The sampled houses, built between 1890 and 1990, are considered to be representative sampling sites for long-term accumulations of attic dust. The mean values of the total U, Th and Cs (mg kg−1) concentrations as well as those of K (m/m %) in attic dust and urban soil samples are 2.4, 3.6, 1.7 and 0.6 and 1.1, 4.4, 1.2 and 0.3, respectively, measured using ICP-MS. The mean activity concentrations of 226Ra, 232Th, 40K and 137Cs in attic dust and urban soil samples are 43.3, 34.0, 534.4 and 88.5 and 25.1, 32.8, 386.4 and 5.6 Bq kg−1, respectively, by using a low-background iron chamber with a well-type HPGe and a n-type coaxial HPGe detector.The elemental compositions (U, Th) and activity concentrations (226Ra, 232Th) along with their abundances in coal ash from the CFPP increase in both studied media as the distance of the sampling sites from the CFPP decreases. Two outlier attic dust samples in particular show significantly high activity concentrations of 226Ra: 145 and 143, of 232Th: 83 and 94 Bq kg−1, which can be considered as a proxy of unweathered coal ash. The calculated total absorbed gamma dose rate (D) and annual effective dose (E) received from urban soils indicate that the presence of the CFPP, coal ash cone and slag dumps does not cause an increase in the level of background radiation in Salgótarján. However, the concentrations of the studied radionuclides are much higher (except for 232Th) and exhibit higher degree of variability in the samples of attic dustthan in those of urban soils. The study suggests that attic dust preserves the undisturbed ‘fingerprints’ of long-term atmospheric deposition thanks to its chemical and physical properties unlike urban soil.

Assessment of natural radioactivity levels in soil samples from Dejen district, Ethiopia.

Gamma ray spectrometry was used to determine the activity concentrations of naturally occurring radionuclides in 12 soil samples collected at random from Dejen district, Ethiopia. In agricultural soils, the calculated mean activity concentrations of 226Ra, 232Th and 40K were 33.44 ± 2.01, 66.02 ± 4.54 and 214.16 ± 8.90 Bq kg-1, respectively, and in virgin soils, they were 38.05 ± 2.48, 61.78 ± 4.76 and 240.32 ± 10.79 Bq kg-1, respectively. The findings were discussed and compared to other studies' findings. The mean values of absorbed dose rate, annual effective dose rate and radium equivalent activity in agricultural land soils are 67.24 nGyh-1, 0.083 mSvy-1 and 144.57 Bq kg-1, and in virgin land soils are 67.53 nGyh-1, 0.082 mSvy-1 and 144.90 Bq kg-1, respectively. These findings were discussed and compared to the internationally recommended value. As a result, it is possible to conclude that the soil samples are safe for residents and those involved in agricultural activities.

Assessment of radioactivity in particulate matter and soil from selected mining towns of Erongo region, Namibia

The presence of radionuclides in particulate matter (PM) associated with mining operations in communities located at the edge of the mine sites have been either greatly ignored or poorly understood, leading to the underestimations of the radionuclides concentrations in PM and health impact. In this study, measurements of radioactivity in PM and soil were made in the two mining towns of Karibib and Arandis to assess the human health radiological impact on the people around the mining sites. Dust fall samples were collected for a period of six months i.e. May 2017 to October 2017 using open bucket sampler procedure according to the American Society for Testing and Materials Standard Method (ASTM D1739) while some soil samples were collected using a soil auger. The samples were measured for the presence radionuclides using a well calibrated gamma-ray spectrometer coupled with a high purity germanium detector.In particulate matter samples, the mean activity concentrations of 226Ra, 238U, 232Th, 210Pb, and 40K were found to be 81.24±1.00, 57.99±2.61, 72.10±1.67, 55.89±6.21, 682±19.81 Bq.kg−1, respectively. Similarly, in soil samples, the mean activity concentrations were found to be 66.41±1.77 Bq.kg−1 for 226Ra, 52.79±3.40 Bq.kg−1 for 238U, 71.30±2.40 Bq.kg−1 for 232Th, Bq.kg−1 for 71.50±5.99 210Pb and 797.36±18.26 Bq.kg−1 for 40K. The activity concentrations revealed higher levels of radionuclides associated with the 238U series, which were distributed unevenly across the sites. The results were comparable to global values of 11 to 64 Bq.kg−1 for 238U, 17 to 60 Bq.kg−1 for 232Th, and 140 to 850 Bq.kg−1 for 40K.The activity concentrations were used to compute the absorbed dose (D), annual effective dose equivalent (AEDE), radium equivalent activity concentrations (Ra eq), external and internal hazard indices (H ex and H in), Gamma Index (Iγ), Alpha Index (Iα) and excess lifetime cancer risk (ELCR). The mean radiological parameters in most samples were found to be within acceptable limits, with Raeq 370 Bq.kg−1, which corresponds to an upper safe limit of AEDE of 1 mSv.yr−1, the prescribed safe limit by the International Commission on Radiological Protection (ICRP), and thus the potential radiological health effects may not be significant.

Environmental radioactivity assessment of the Brunei Darussalam coastline of the South China Sea

Radioactivity levels of naturally occurring radionuclides at the coast of Brunei Darussalam were evaluated along with their dose rates. Twenty-six berm and intertidal sediment samples were measured using gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th and 40K in berm sediments were 10.07 ± 1.02 Bq/kg, below the minimum detectable activity, and 21.44 ± 1.23 Bq/kg, respectively, whereas for intertidal sediments they were 7.01 ± 0.87, 1.67 ± 0.15 and 4.99 ± 0.42 Bq/kg, respectively. With respect to the radiological health risk, the average hazard indices, absorbed gamma dose rate, effective dose equivalent, and excess lifetime cancer risk were found to be less than the global average. Calculation of the activity ratio showed that 40K is the main source of radiation in the coastal sediments. Furthermore, the difference in radioactivity levels between the berm sediments and intertidal sediments collected at the same location was investigated. Finally, a standard geological terminology of the littoral zone profile is proposed for describing coastal samples for universal communication among researchers.

Assessment of occupational radiation exposure of NORM scales residues from oil and gas production

Radiological hazards from external exposure of naturally occurring radioactive materials (NORM) scales residues, generated during the extraction process of oil and gas production in southern Algeria, are evaluated. The activity concentrations of 226Ra, 232Th, and 40K were measured using high-purity gamma-ray spectrometry (GeHP). Mean activity concentration of 226Ra, 232Th and 40K, found in scale samples are 4082 ± 41, 1060 ± 38 and 568 ± 36 Bq kg−1, respectively. Radiological hazard parameters, such as radium equivalent (Raeq), external and internal hazard indices (Hex, Hin), and gamma index (Iγ) are also evaluated. All hazard parameter values were greater than the permissible and recommended limits and the average annual effective dose value exceeded the dose constraint (0.3 mSv y−1). However, for occasionally exposed workers, the dose rate of 0.65 ± 0.02 mSv y−1 is lower than recommended limit of 1 mSv y−1 for public.

Measurements of natural radioactivity and evaluation of radiation hazard indices in soils around the Manyoni uranium deposit in Tanzania

Pre-mining natural radioactivity levels in soils over a 27.96 km2 site around the Manyoni Uranium Project in Tanzania were determined by a high purity germanium detector. The mean activity concentrations of 226Ra, 232Th, and 40K in soils were 227.43 ± 38.79 Bq/kg, 65.22 ± 3.70 Bq/kg, and 107.32 ± 23.07 Bq/kg, respectively. The average radium equivalent activity (Raeq), external hazard index (Hex), and internal hazard index (Hin) at these concentrations were 328.95 Bq/kg, 0.89, and 1.50, respectively. The mean absorbed dose rate in air at 1 m above the ground (Da) was 148.94 nGy/h, and the mean outdoor annual effective dose (Ed) was 0.18 mSv/y. Additionally, natural radioactivity levels in soils over a 0.71 km2 site, which is inside the 27.96 km2 site, which is prone to mine dust pollution above healthy levels, were also determined. The mean activity concentrations of 226Ra, 232Th, and 40K in the soils from this site were 380.4 ± 59.93 Bq/kg, 78.69 ± 8.99 Bq/kg, and 70.40 ± 7.91 Bq/kg, respectively. The corresponding means for Raeq, Hex, and Hin were 498.35 Bq/kg, 1.35, and 2.37, respectively. The mean Da and Ed were 226.21 nGy/h and 0.28 mSv/y, respectively. The average values of Ed at both sites were less than the public exposure limit of 1 mSv/y. This means that the sites have normal background radiation levels that do not endanger people's health when they engage in outdoor activities. When mining begins, the natural radioactivity levels obtained in this study, rather than national or global averages, can be used by mine owners or government agencies to assess the environmental effects of mining. Even after mining and during decommissioning, these baseline levels can also be used to measure how well the land has been restored.

Transfer factor of radionuclides from soil to cereal crops around gold mining and evaluation of corresponding radiological hazard levels Oromia, Ethiopia

ABSTRACT Radionuclide distribution and transfer factors in plants are decisive parameters used to evaluate radioactive contamination in the environment and its radiological health risks to humans. In this study, the activities concentration of 226Ra, 232Th, and 40K were measured using NaI(Tl) gamma-ray spectrometry on soils and on corresponding teff and wheat plant samples analyzed collected from Sakaro gold mining area from Reji kebele, Oromia, Ethiopia. The results of mean activity concentration of 226Ra, 232Th, and 40K samples analyzedzed in soil, teff, and wheat samples were found to be 33.05 ± 0.72, 13.7 ± 0.51 and 220.18 ± 0.61 Bq.kg-1, 3.93 ± 0.4,27 ± 0.61 and 148.3 ± 0.5 Bq.kg-1 and 3.22 ± 0.43, 4.59 ± 0.64 and 229.8 ± 0.5 Bq.kg-1 respectively. Results showed that the activity concentration of radionuclides in this study area was within the limit. The transfer factors from soil to cereal crops (teff and wheat) were compared with the study done in a different country of the world and its values were below unity except for 40K in wheat samples. The absorbed dose rate, annual effective dose rate, external and internal hazards index, lifetime cancer risk, and annual effective ingestion dose were estimated and were also compared with the internationally accepted values. It was found that none of the results exceeded the recommended limit value.

Evaluation of Radionuclides Transfer Factors and Ingestion Dose from Plants Around Mining Sites in Adamawa State Nigeria

Illegal mining activities has become rampant in Adamawa State Nigeria, contaminating the soil with radionuclides which can be transferred to the food crops farmed in the host communities. Ingestion of such plants could cause harmful effects. In this study, radionuclide transfer factor from soil to plants and internal exposure dose around mining sites in Adamawa State were evaluated. 30 (15 soil, 15 plant) samples were analyzed for activity concentrations of 226Ra, 232Th and 40K. The transfer factor from soil to plant was calculated and the ingestion dose was also calculated using the Integrated Module for Bioassay Analysis (IMBA). Result shows that the mean activity concentrations of 226Ra, 232Th and 40K in the soil are 106.32Bq/kg, 84.34Bq/kg and 466.14Bq/kg, while for plants are 98.42Bq/kg, 72.69Bq/kg and 274.07Bq/kg respectively. These values were above the world average by United Nations Scientific Community on the Effects of Atomic Radiation (UNSCEAR) 35Bq/kg, 30Bq/kg and 400Bq/kg except for 40K which was lower in plant samples. Mean transfer factors were 0.942, 0.919 and 1.149 respectively, corresponding to a mean ingestion dose of 1.02E-01mSv/y, indicating high transfer factor in all the mining sites and high ingestion doses. Even though the mean ingestion dose was low, ingestion of such plants may pose radiation risk to the host communities in a long time. Therefore, proper policy by regulatory authorities must be put in place to protect the host community and the public from high ingestion doses that accounts for internal radiation exposure especially mining sites A, B and C.

Radiological hazard assessment of natural radioactivity in Avcilar region, Turkey: a case of Istanbul University-Cerrahpasa Avcilar Campus

ABSTRACT Radionuclides 226Ra, 232Th, and 40K can be found in various concentrations in the surface soil. High concentrations of radionuclides in the surface soil may cause radiological risks. This study investigated natural radioactivity levels and artificial radionuclide (137Cs) levels in the Istanbul University-Cerrahpasa, Avcilar region, Istanbul, Turkey. Radioactivity concentrations were analyzed using the gamma-ray spectrometer. The mean activity concentration of 226Ra, 232Th, 40K, and 137Cs is 28.55, 29.57, 385.72, and 3.09 Bq kg−1, respectively. Radiological parameters radium equivalent activity, absorbed dose rate, annual effective dose equivalent, external hazard index, and excess lifetime cancer risk were calculated using activity concentrations. The radiological parameters values were lower than UNSCEAR values, except for the annual gonadal dose equivalent (approximately 10% higher). There is a strong correlation between radiological parameters and radionuclides. Generally, the activities of radionuclides in the region fall within the recommended limits, thus Istanbul-Avcilar region can be considered safe for settlement.