Natural and artificial radioactivity distribution in soil, rock and water of the Central Ashanti Gold Mine, Ghana

Direct gamma spectrometry study was carried out within and around the operational area of the Central Ashanti Gold of Ghana to ascertain the baseline radioactivity levels of naturally occurring radioactive materials (NORM), prior to processing of gold ore at the mine. The average activity concentrations of ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs in the soil/rock samples were 64.3, 68.4, 1243.9 and 3.5 Bqkg^?1, respectively. For the water samples, the average activity concentrations were 2.5, 2.6, 14.7 and 0.7 BqL^?1 for ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs, respectively. The total annual effective dose to the public was estimated to be 0.141 mSv which is below the ICRP recommended level of 1 mSv for public exposure control. The average radium equivalent activity value was 257.8 Bqkg^?1 in the range of 72.9–402.3 Bqkg^?1. The average values of external and internal indices were 0.7 and 0.8, respectively. The concentrations of U, Th and K were variable in soil and rock samples taken from different locations in the study area with values varying in the range of 0.8–10.9, 2.4–39.4 μg/g and 0.7–6.3 %, respectively. The concentration values of gross-α and gross-β for all the water samples were below the Ghana Standards Board and Who Health Organisation recommended guideline values for drinking water quality. The results obtained in this study shows that radiation levels are within the natural background radiation levels found in literature and compared well with similar studies for other countries.     

Assessment of natural radioactivity,associated radiological health hazards indices and soil-to-crop transfer factors in cultivated area around a fertilizer factory in Onne,Nigeria

Concentration of natural radionuclides in three major staple food crops cultivated around a fertilizer plant in Onne, Rivers State Nigeria and the cultivated soil samples were determined using gamma spectroscopy operated on a Canberra vertical high purity 3″ × 3″ NaI(TI) detector. The average activity concentration of ²³⁸U, ²³²Th and ⁴⁰K was determined, for cassava flour (U 19.3 ± 5.0, Th 11.4 ± 3.3, K 426.9 ± 33.8) Bq kg^?1, for yam flour (U 6.3 ± 1.8, Th 8.4 ± 2.6, K 227.0.9 ± 27.3) Bq kg^?1 while for cocoyam flour (U 7.5 ± 2.7, Th 7.1 ± 2.3, K 195.8 ± 25.83) Bq kg^?1. The mean activity concentration for soil samples is 18.7 ± 3.7 Bq kg^?1, 18.0 ± 3.8 Bq kg^?1 and 308.4 ± 22.4 Bq kg^?1 for ²³⁸U, ²³²Th and ⁴⁰K, respectively. These values obtained show enhanced ⁴⁰K concentration which is attributed to the effluent discharge from a fertilizer plant and its applications to farmlands, but ²³⁸U, ²³²Th values are well within the global average and values reported in some regions and countries of the world. Radiation hazard indices obtained to estimate potential radiological health risk in both foodstuffs and soil samples are well below their permissible limit as set by UNSCEAR [Sources and effects of ionizing radiation (Report to the General Assembly), 2000]. The rate of radionuclides transfer from soil to crops was moderate with mean transfer factors of ²³²Th < ²³⁸U < ⁴⁰K.     

Determination of radioactivity levels in Akhisar,Gördes,Gölmarmara and Sindirgi regions,Western Turkey

In this study, radioactivity measurements in the environment of Akhisar, Gölmarmara, Gördes and Sindirgi regions in Western Turkey were investigated in order to evaluate the implications of any excess radioactivity in the environment of geological formation. The radioactivity concentrations of ⁴⁰K, ²³⁸U and ²³²Th radionuclides in the soil samples were measured by a NaI(Tl) gamma spectrometer system, and the radium activity concentrations in the water samples were also analyzed by an ZnS(Ag) alpha counter by the collector chamber method. The radioactivity of ⁴⁰K, ²³⁸U and ²³²Th in soils ranged 2.80–2,347.77, 9.90–256.19 and 9.66–106.53 Bq kg^?1, respectively. The activity of ²²⁶Ra in the water samples ranged from 0.03 Bq L^?1 (0.89pCi/L) to 0.80 Bq L^?1 (21.58pCi/L). In addition, the external terrestrial gamma dose rate in air (nGy h^?1), annual effective dose rate (mSv year^?1) and radium equivalent activity (Bq kg^?1) were calculated and compared with international standard values.     

Distribution of 238U, 232Th and 40K in plutonic rocks of Greece

One hundred and twenty one samples from every major plutonic body (mainly granitic) of Greece have been analyzed by γ-ray spectrometry to determine the specific activities of ²³⁸U, ²³²Th and ⁴⁰K (Bq/kg). The range of the activity concentrations of these radionuclides was 2.3–266.4, 1.8–375.5 and 55.0–1632.0 Bq/kg and their average values were 79.2, 85.3 and 881.4 Bq/kg respectively. Any possible connection between the specific activities of ²³⁸U, ²³²Th and ⁴⁰K and some characteristics of the studied samples (age, rock-type, colour, grain-size, occurrence and chemical composition) is investigated. Samples of particular colour, rock-type, occurrence and chemical composition have been identified for their distinctive levels of natural radioactivity, while age and grain-size do not affect the concentrations of ²³⁸U, ²³²Th and ⁴⁰K. The range of the Th/U ratio was 0.7–12.69. This great variation in the Th/U ratios, especially when it is found among the samples of the same pluton, is also discussed and explained by alteration and tectonic–metamorphic processes.     

Natural radioactivity levels and evaluation of radiological hazards from Beni Haroun dam sediment samples,northeast Algeria

Levels of naturally occurring radioactivity in sediment samples of Beni Haroun dam have been investigated. The activity concentrations of ²³⁸U and ²³²Th decay chains and ⁴⁰K primordial radionuclide have been measured using high-resolution HPGe detector. Activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K radionuclides were found in the ranges 9–66, 14–37, and 177–288 Bq/kg with the mean values 24.67, 25.98, and 208.10 Bq/kg, respectively. Radiological hazard parameters were estimated based on the activity concentrations for ²²⁶Ra, ²³²Th, and ⁴⁰K to find out any radiation hazard associated with the sediments. Correlation studies between pairs of radionuclides were performed and discussed, and the obtained results are compared with international recommended values.     

Anomalous concentrations of radionuclides in the groundwater of Ede area,southwestern Nigeria: a direct impact of geology

An assessment of the groundwater in areas underlain by pegmatite in Ede, southwestern Nigeria was carried out to determine the concentration of Potassium-40 (⁴⁰K), Uranium-238 (²³⁸U) and Thorium-232 (²³²Th) radionuclides. In the earlier work, it was established that zircons in these pegmatites have suffered a high degree of metamictization that has enhanced continuous loss of some radionuclides since the time of emplacement of the pegmatite host rock to the present. The aim of this work is to determine whether or not there is corresponding increase in the concentration of radionuclides in groundwater in the study area. Fifteen groundwater samples were collected from both hand dug wells and boreholes in the area. Ten samples were from Ede town, two samples each from nearby communities of Iddo and Ekuro and one from Iwoye, where the bedrocks were not pegmatites. All the 15 samples were analyzed with the Sodium Iodide scintillator (NaI [Tl]) detector at the Centre for Energy Research and Development, Obafemi Awolowo University, Ile-Ife, Nigeria. The results showed varying concentrations of the radionuclides in the water samples. Activity concentrations of Potassium-40 (⁴⁰K) indicated an average value of 17.149 Bq/L for samples from Ede, 9.265 Bq/L for Iddo, 6.6 Bq/L for Ekuro, while Iwoye has a value of 21.21 Bq/L. The Uranium-238 (²³⁸U) series had an average value of 13.64 Bq/L for Ede, 13.49 Bq/L for Ekuro, 11.685 Bq/L for Iddo and 12.04 Bq/L for the lone sample from Iwoye. Thorium-232 (²³²Th) series had an average value of 11.182 Bq/L for Ede, while average values of 7.79 Bq/L and 9.025 Bq/L, respectively, were recorded for Iddo and Ekuro and 12.25 Bq/L for Iwoye. The annual effective dose level of ⁴⁰K is generally below the World Health Organization (WHO) recommended dosage of 0.1 mSv/y except for three locations, while those of ²³⁸U and ²³²Th are in excess of the standard values. The high radionuclides in the groundwater in the study area were not due to anthropogenic sources but directly due to geological processes which release the radioisotopes from rocks after weathering, continuous loss from metamict minerals and natural lateral mobility from regions of radionuclides’ release to other areas. There is thus the need to carry out systematic studies of the radionuclides concentrations on regional scale in the area which could lead to investigating on both short- and long-term health effects on organic species in these areas, and development of purification systems before utilizing water from the areas for domestic and industrial purposes.     

Natural radionuclide concentrations in thermal springs of east Algeria

The variation of the natural radionuclide concentrations depends on the chemical composition of each site. In this work, two thermal springs in the east of Algeria have been chosen to assess the activity concentration of natural radionuclide, mainly the three natural radioactive series ²³⁸U, ²³⁵U and ²³²Th, and ⁴⁰K. The high-resolution gamma ray spectroscopy was used to determine these concentrations. In these water samples, ²³⁵U, ²³⁴Th, ²¹⁰Pb, ²²⁶Ra radionuclides are less than the minimum detectable activity. The activity of ²³⁸U is dominant. The ²³⁸U activity was determined by taking the mean activity of two separate photo-peaks of daughter nuclides ²¹⁴Pb at 351.92 (37.2%) keV and ²¹⁴Bi at 609.31 (45%) keV. The measured activity concentrations of ²³⁸U in water samples obtained from the concentrations of ²¹⁴Bi and ²¹⁴Pb ranged from 0.56 ± 0.20 to 1.13 ± 0.20 Bq/L. The annual effective dose value due to the ingestion of the measured radionuclide ²³⁸U in 1 L of water, for an adult, ranged from 9.20 to 18.56 µSv.     

Assessment of lifetime cancer risk from natural radioactivity levels in Kadikoy and Uskudar District of Istanbul

The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K are measured in soil samples from various locations in the Kadikoy and Uskudar district of Istanbul (Turkey). The ²²⁶Ra activity concentrations range from 19.97 Bqkg^?1 to 50.80 Bqkg^?1 and average ²²⁶Ra concentration value 31.40 Bqkg^?1 was calculated. The ²³²Th activity concentrations range from 21.38 Bqkg^?1 to 52.61 Bqkg^?1 and average ²³²Th concentration value 34.44 Bqkg^?1 was calculated. The ⁴⁰K activity concentrations range from 464.06 Bqkg^?1 to 711.27 Bqkg^?1 and average ⁴⁰K concentration value 619.59 Bqkg^?1 was calculated. In addition, radium equivalent (Ra_eq), absorbed gamma dose rate (D), annual effective dose equivalent, (AEDE), excess lifetime cancer risk (ELCR) were calculated in this study. All of the calculations have been compared with both national and international standards and similar studies. As a result of this comparison, levels of natural radioactivity and radiological effects were slightly higher than the World average and Turkey.     

Assessment of radiation hazards due to the concentration of natural radionuclides in the environment

A study of natural radionuclides and radon concentration of Hamirpur District of Himachal Pradesh, India is carried out using various methodologies. The activity concentration of the natural radionuclides viz. ²²⁶Ra, ²³²Th and ⁴⁰K is measured using high-resolution-based HPGe detector. Indoor radon measurements in the dwellings of Hamirpur district is carried out using LR-115 type II cellulose nitrate films in the bare mode. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K are 35.58, 54.95 and 580.58 Bq kg^?1, respectively. The annual average indoor radon value in the study area varies from 173.90 to 198.25 Bq m^?3, which is well within the recommended action level given by International Commission on Radiological Protection. The indoor radon values obtained in the present investigation are higher than the world average of 40 Bq m^?3. Radon concentration in water samples is measured using RAD7, an active radon detector. The annual effective dose for stomach and lung is determined from the measured value of radon concentration in water. To assess the radiation hazard of the natural radioactivity in all samples to the people, the radium equivalent activity, external hazard index, lifetime fatality risk, absorbed dose rate and total annual effective dose is estimated. The results signify that the studied area does not possess any radiation hazards due to the presence of natural radioactivity concentration.     

Evaluation of dose parameters and radiological hazards in gravel samples of Konyaaltı Beach,Antalya

It is important to know the distribution and transfer of radionuclides such as uranium, thorium, and potassium, which exist naturally in the environment we live in. For this reason, measurements of these natural radionuclides have been carried out for 15 gravel samples collected from Konyaalt? Beach, Antalya. In order to measure the natural activity concentrations of potassium-40, uranium-238, and thorium-232 radionuclides, we performed the measurements by applying a gamma spectrometry method with a “3?×?3” NaI(Tl) detector, which is a multichannel analytical detector in the Suleyman Demirel University gamma spectrometry laboratory. The minimum, maximum, and mean values for the ²²⁶Ra activity concentration were measured as 19.74 Bq/kg, 37.03 Bq/kg, and 31.64 Bq/kg, respectively. The minimum, maximum, and mean values for the ²³²Th activity concentration were measured as 12.76 Bq/kg, 34.32 Bq/kg, and 26.67 Bq/kg, respectively. The minimum, maximum, and mean values for the ⁴⁰K activity concentration were measured as 196.37 Bq/kg, 421.13 Bq/kg, and 350.42 Bq/kg, respectively. Dose parameters and radiation damage indices were calculated using experimentally measured activity results and the resulting dose and hazard index values were compared with the determined limit values. It can be concluded that no risk may threat in terms of the hazard index values. In addition, all results obtained in terms of calculated dose values except for annual gonadal dose are below the recommended limit values.     

New information on radionuclides concentration in phosphorites originating from Tunisia and Algeria

In this study we investigate the radiological hazard of naturally occurring radioactive material in Tunisian and Algerian phosphorite deposits. Eight samples of phosphorite were collected from the phosphorite mines. The Tunisian and Algerian phosphorites occur in the Late Paleocene and Lower Eocene (Ypresian-Lutetian) in age (Béji Sassi 1984 and Zaïer 1999). Activity concentrations in all the samples were measured by alpha spectrometry and gamma spectrometry. Alpha spectrometry analyses show that the specific activity values of ²³⁸U, ²³⁴U and ²³⁵U in the samples of Tunisian phosphorite were 327?±?7 (321–327), 326?±?6 (325–331) and 14.50?±?0.72 (13.90–15.57) Bq kg^?1, respectively. Specific activity measured by gamma spectrometry in the samples of the Tunisian and Algerian phosphorite shows a small difference. Specific activity levels of ⁴⁰K, ²²⁶Ra, ²³²Th, ²³⁵U and ²³⁸U in the phosphorite samples from Tunisia were, respectively, 71.10?±?3.80, 391.54?±?9.39, 60.38?±?3.74, 12.72?±?0.54 and 527.42?±?49.57 Bq kg^?1 and Algeria were 15.72?±?1.73, 989.65?±?12.52, 12.08?±?1.20, 47.50?±?1.52 and 1,148.78?±?7.30 Bq kg^?1, respectively. The measured value of specific activity of ²³²Th and ⁴⁰K in the Tunisian phosphorite samples is relatively higher than that found in the samples of Algerian phosphorite. The measured activity of uranium (²³⁸U) in the Tunisian phosphorite (527?±?49) Bq kg^?1 is lower than in Algerian phosphorite. The measured activity of ²³⁸U in the Tunisian phosphorite samples was (527–1,315?±?65) ²³⁸U Bq kg^?1 which is higher than its maximum background value of 110 Bq kg^?1 in soils of the various countries of the world (Tufail et al. Radiat Meas 41:443–451, 2006). Different geological origins of phosphorites deposits are the main reason for the large spread in worldwide specific activities. The obtained results of uranium concentrations in phosphorites of different types (Algerian and Tunisian) demonstrate that the uranium concentrations are mainly governed by the phosphatic material. The present study reveals that phosphorite deposits contain natural radioactivity higher than background level.     

Determination of natural radioactivity levels in soil and travertine of the region of Tokat and Sivas,Turkey

In this study, the environmental radioactivity measurements for Tokat and Sivas provinces in the northeast of Turkey were performed. Using gamma ray spectrometry, the activity concentrations of natural radionuclides in soil and travertine samples (²³²Th, ²²⁶Ra, and ⁴⁰K) were determined. The annual effective dose equivalent, the absorbed doses rate in air, the radium equivalent, and the external hazard index were obtained from these activities. The activity concentrations vary from 9.09 to 17.04 Bq kg^?1 for ²³²Th, from 36.53 to 76.95 Bq kg^?1 for ²²⁶Ra, and from 216.56 to 576.59 Bq kg^?1 for ⁴⁰K in soil samples. The activity concentrations in travertines vary from 15.99 to 21.01 Bq kg^?1 for ²³²Th, from 19.89 to 67.71 Bq kg^?1 for ²²⁶Ra, and from 179.89 to 314.43 Bq kg^?1 for ⁴⁰K. The average dose rate in air for soil and travertine samples was 43.41 and 41.05 nGy h^?1 respectively. The obtained results are presented and compared with other studies, and the results of this study are lower than the international recommended value (55 nGy h^?1) given by UNSCEAR ( 2000). The results show that the region has a background radiation level within the natural limits.     

Gamma emitters in Hong Kong water

Water samples, representing seawater, river water, reservoir water, drinking water, and underground water were studied through gamma-ray spectral analysis. Only gamma emitters in the²³⁸U and²³²Th series and⁴⁰K were detected. No fission product was detected with specific activity above 0.1 Bq/kg. The present data could be the baseline for future monitoring of the radioactivity released from a nuclear plant being built at a 50-km distance from Hong Kong. The variation of detected specific activities may be due to geological differences and the effect of plants.     

Radiation impact assessment of naturally occurring radionuclides and magnetic mineral studies of Bharathapuzha river sediments,South India

The natural radioactivity levels and magnetic measurements in sediment samples of Bharathapuzha river for the first time have been determined. Bottom sediments from 33 locations were collected to determine ²²⁶Ra, ²³²Th and ⁴⁰K using a HPGe detector based on the high-resolution gamma spectrometry system, and magnetic susceptibility by using Bartington MS2 magnetic susceptibility meter. The calculated activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K have been found to vary from 21.21 to 66.03 Bq kg^?1, 33.49 to 93.10 Bq kg^?1 and 232.25 to 899.66 Bq kg^?1, respectively. The results have been compared with worldwide recommended values and also with radioactivity measurements in river sediments of India and other parts of the world. The air-absorbed dose rate, indoor and outdoor annual effective dose rates and radium equivalent activity are calculated with an aim to access the radiation hazards arising due to the use of these materials in the construction of buildings and their mean values obtained are 74.83 nGy h^?1, 367.08 μSv y^?1, 91.77 μSv y^?1 and 157.09 Bq kg^?1, respectively. The mass-specific magnetic susceptibility values ranged widely from 35.4 to 2,160.5 × 10^?8 m³ kg^?1 and compared with other rivers in South India. Multivariate statistical analyses were performed to describe the magnetic and radioactivity relevance of the different groups of samples. The data obtained in the present study may be useful for radiological and magnetic mapping of the study area in the future.     

青岛市地表天然放射性水平及其主控因素特征

通过对青岛市1500km^2范围内大密度土壤放射性核素（^238U、^232Th和^40K）和地表γ辐射测量,系统深入地研究了其放射性特征、分布规律及其影响因素。结果表明,青岛市土壤中核素^232Th和咏的放射性比活度偏高,而^238U偏低。地表γ辐射吸收剂量率（平均值91．87nGy·h^-1）略高于全国和世界平均值,研究发现地表93．14％的γ辐射来自地面放射性核素^238U、^232Th和^40K）的．γ辐射,其中^232Th和^40K的贡献占81．21％,是主要的贡献者。地质背景是影响地面γ辐射吸收剂量率的主要因素,燕山期各类花岗岩是导致青岛市区-王哥庄-带γ辐射吸收剂量率偏高的主要原因;同时环境因素（路面材料、地貌景观）对地表γ辐射吸收剂量率也存在一定影响。虽然研究区的γ辐射吸收剂量率较高,但其年有效剂量（0．56 mSv）远低于公众照射年剂量当量限值1.0 mSv,人居环境基本不受影响。     

A study of natural radioactivity levels of soil in the Lincang Basin, Yunnan

Influenced by the Indosinian Lincang granite,the level the natural radioactivity in the Lincang Basin is relatively high.This work deals with the determination of natural radioactivity of soil in this area by using theγ-ray spectrometer.The specific activities of 2 26Ra, 238U, 232Th and 40K obtained were obviously greater than the average values of these nuclides countrywide and worldwide,which were 53.4(from 38.7 to 62.8),161.2(from 127.3 to 211.7),120.9(from 106.5 to 140.6)and 632.2(from 521.7 to 707.5)Bq/kg.Based on the research data,the level of natural radioactivity of the granite was high,which impacts and provides a good source of soil radioactivity in the study area.To assess the radiological hazard of the natural radioactivity in soil,the γ-absorbed dose rate and annual effective dose rate were calculated.The results show that,although the γ-absorbed dose rate in the study area is a little high,the annual effective dose rate is lower than the recommended value.So the Lincang Basin is safe with respect to radiological level and its living environment is not affected.     

Measurement of natural radioactivity in sand samples collected from the Baoji Weihe Sands Park, China

The activity concentrations and the gamma-absorbed dose rates of the primordial naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K were determined for sand samples collected from the Baoji Weihe Sands Park, China, using γ-ray spectrometry. The natural radioactivity concentration of sand ranges from 10.2 to 38.3 Bq kg⁻¹ for ²²⁶Ra, 27.0 to 48.8 Bq kg⁻¹ for ²³²Th and 635.8 to 1,126.7 Bq kg⁻¹ for ⁴⁰K with mean values of 22.1, 39.0 and 859.1 Bq kg⁻¹, respectively. The concentrations of these radionuclides are compared with the typical world values and the average activity of Chinese soil. The measured activity concentration of ²²⁶Ra and ²³²Th in sand is lower than the world average while that of ⁴⁰K is higher. . To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate, and the effective dose rate have been calculated and compared with internationally approved values. The radium equivalent activity values of all sand samples are lower than the limit of 370 Bq kg⁻¹. The values of the external hazard index are less than unity. The mean outdoor air absorbed dose rate is 69.6 nGy h⁻¹ and the corresponding outdoor effective dose rate is 0.085 mSv y⁻¹.     

An analysis of naturally occurring radionuclides and <Superscript>137</Superscript>Cs in the soils of urban areas using gamma-ray spectrometry

This study of environmental radioactivity was carried out in the soils of an urban area. Naturally occurring gamma-emitting radionuclides and man-made ¹³⁷Cs were found in the soil profiles collected from four parks in the central Belgrade city area and the soil layer was examined every 10 cm and to a depth of 50 cm. Radioisotope activity concentrations (Bq kg^?1) in the samples of urban soil using the gamma-ray spectrometry method were in the range of 14–46 for ²³⁸U, 33–50 for ²²⁶Ra, 29–63 for ²¹⁰Pb, 1.2–3.4 for ²³⁵U, 28–50 for ²³²Th, 424–576 for ⁴⁰K and 0.7–35.8 for ¹³⁷Cs. Some of the basic physicochemical soil properties (pH, organic matter content, calcium-carbonate content, particle size distribution) were determined to investigate the impact on the vertical distribution of radionuclides. The results of this investigation showed that variations of activity concentration ratios of radionuclides that belong to the same (²³⁸U/²²⁶Ra) or different radioactive series (²³²Th/²²⁶Ra; ²³⁵U/²³⁸U), including ²¹⁰Pb/¹³⁷Cs ratios could well be explained by the properties of the soil. Alkaline pH reaction, the accumulation of organic matter in the uppermost and of carbonates in the deepest layers of urban soil had an effect on ²³⁸U/²²⁶Ra, and ²¹⁰Pb/¹³⁷Cs activity concentration ratio values, while ²³²Th/²²⁶Ra and partially ²³⁵U/²³⁸U ratios were associated with the particle sizes vertical distribution. A study of radionuclides in the samples of leaves of two deciduous tree species common for these parks was also conducted and ²¹⁰Pb and ⁴⁰K were found concentrated in leaves rather than other investigated radionuclides.     

Gamma radiation levels in the villages of South Konkan,Maharashtra, India

Ambient gamma radiation study was carried out in South Konkan using thermo luminescent dosimeters (TLDs). A statistical analysis was carried out to understand the distribution of gamma radiation in the study area. The annual effective doses (AEDs) received by the local population from the selected villages were 0.31 and 0.09 mSv year^?1 for indoor and outdoor locations, respectively. For indoor conditions, the maximum dose rate occurred for winter season and the minimum occurred in monsoon season while for outdoor conditions the maximum dose rate occurred in spring season and minimum occurred in the monsoon season. The terrestrial radioactivity in the corresponding villages was measured by a HpGe detector. The radiation hazard indices like absorbed dose rate in air (D), radium equivalent activity (Ra_eq), external hazard index (H _ex) and internal hazard index (H _in), and AED were calculated using soil radioactivity data. The minimum absorbed dose rate in air (33.97 nGy h^?1) corresponds to the Dale village and the maximum (101.86 nGy h^?1) corresponds to the Mithgawane village. Radiation hazard indices as Ra_eq, H _ex, and H _in were found to be within the limit. The average AED from natural radionuclides was found to be lower than the worldwide value. The AEDs of this study were compared with previous studies carried out worldwide. A positive correlation was observed for the absorbed dose rate in air and the activity concentration of U-238, Th-232, and K-40. A positive correlation between activity concentrations of U-238, Th-232, and K-40 was also observed. The comparison between the AEDs calculated using absorbed dose measured by TLDs and the values calculated from soil’s gamma spectrometry showed some variation in the villages of South Konkan.     

Estimation of excess lifetime cancer risk and radiation hazard indices in southern Iraq

Relatively high activity concentrations of some radionuclides (²²⁶Ra, ²³⁸U, ²³²Th, and ⁴⁰K) have been measured in surface and subsurface soils in areas (southern Iraq) where many warfare actions have taken place during the Iran–Iraq and Gulf wars. Such high activity concentrations might be related to the increase in cancerous injuries and birth defects recently reported. The study was aimed to estimate the activity concentrations of some nuclides and a comparison of results with international health hazard indices. In addition, the excess lifetime cancer risk (ELCR) was assessed. Soil samples were collected at three depths (0, 30, and 60 cm) in three locations in Abu Al Khasib and Ad Dayr in Basrah governorates. The average activity concentrations were estimated employing hyper-pure germanium HPGe gamma-ray detection technology. The values obtained in Abu Al Khasib were: 58.44 Bq/kg (²²⁶Ra), 43.56 Bq/kg (²³⁸U), 19.38 Bq/kg (²³²Th), and 321.76 Bq/kg (⁴⁰K) whereas in Ad Dayr 45.71 Bq/kg (²²⁶Ra), 35.53 Bq/kg (²³⁸U), 20.33 Bq/kg (²³²Th), and 337.02 Bq/kg (⁴⁰K). According to UNSCEAR (Sources and effects of ionizing radiations: a report on the effects of atomic radiation to the general assembly with scientific annexes, Annex B, United Nations, New York, 2000) report, higher levels of ²²⁶Ra, ²³⁸U concentrations than the world’s average values (35 Bq/kg) were observed in both locations. In addition, some radiation hazard indices were determined for both locations: average outdoor external dose (D _out), average indoor external dose (D _in), total average value of the external dose (D _tot), average annual outdoor effective dose (E _out), average annual indoor effective dose (E _in), and averaged total annual effective dose (E _tot). Values for D _tot and E _tot were higher than the worldwide median (143 nGy/h and 0.48 mSv/y, respectively) in both regions. The measured values of activity concentrations were also used to estimate the outdoor, indoor, and total ELCR. The ELCR values were higher than the worldwide averages. Further analyses and studies need to assess the real risks for human health and possible soil remediation.