Natural radioactivity and its gamma dose rate in Mission (Texas) soils

The activity concentration of radionuclides in ²³⁸U, ²³²Th, and ⁴⁰K were determined in Mission (Texas) surface soils through gamma-ray spectrometry measurements using hyper pure germanium detector. Activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were 13–32 Bq kg^?1 (mean value: 23 Bq kg^?1), 17–47 Bq kg^?1 (mean value: 31 Bq kg^?1), and 100–460 Bq kg^?1 (mean value: 300 Bq kg^?1) respectively. The absorbed gamma dose rate in air from these soils were found in the range of 23 to 56 nGy h^?1 with an average value of 42 nGy h^?1. The contribution to the absorbed gamma dose rate in air was observed as 26 % from ²³⁸U, 45 % from ²³²Th, and 29 % from ⁴⁰K. The outdoor annual effective dose equivalent varied between 28 and 69 μSv y^?1 with the mean value of 52 μSv y^?1.The evaluated data were compared with the data from different countries and also with the world mean value.     

Measurement of activity concentration of primordial radionuclides in soil samples from Thirthahalli taluk and the assessment of resulting radiation dose

The activity concentration of primordial radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K in soil samples of Thirthahalli taluk were measured systematically by using a low background HPGe detector coupled to 16 K MCA. The measured activity concentration of ²²⁶Ra lies between 5.1?±?0.2 and 79.5?±?1.7 Bq kg^?1with an average activity of 25.99 Bq kg^?1, ²³²Th ranges from 5.1?±?0.3 to 95.3?±?2.2 Bq kg^?1with an average activity of 33.60 Bq kg^?1and that of ⁴⁰K varies from 18.3?±?1.5 to 833.4?±?17.5 Bq kg^?1with an average activity of 175.52 Bq kg^?1. Higher concentration of these radionuclides were found in the soil samples where the regional geology is granites. The consequential gamma dose and the corresponding radiation hazard was also estimated and is found to be within the permissible limits. The possible radiological impact on the public was also determined and these results are presented in this paper.     

Gamma background measurements in the Boulby Underground Laboratory

To determine background radiation levels that might influence experiments, we measured in situ gamma-ray emissions at ten locations in the Boulby Underground Laboratory. For gamma radiation in the energy range of 7–2,734 keV, the counts varied from 6.5 to 28 γ s^?1. For measurements inside the Lab, the arithmetic mean was 24 γ s^?1. The sedimentary rocks that surrounded the Lab, halite and mudstone, were characterized by very low activity concentrations of uranium (0.8–7.1 Bq kg^?1) and thorium (0.6–3.9 Bq kg^?1).     

Measurement of naturally occurring radioactive materials (NORM) in beach sand minerals using HPGe based gamma-ray spectrometry

This paper discusses the measurement of naturally occurring radioactivity materials (NORM) in beach sand minerals using high resolution gamma spectrometry. In India, the beach sand minerals of economic interest from coastal Kerala, Tamil Nadu and Orissa are enriched with NORM due to the occurrence of monazite deposits and heavy minerals such as zircon, ilmenite, magnetite, garnet, rutile etc. Since many of these ores are rich in ²³²Th and other radio elements, certification of radioactivity levels has become mandatory in recent years. The average activity concentrations of ²²⁶Ra in zircon, rutile and garnet were 3,531, 1,134 and 17 Bq kg^?1, respectively. The average activity concentration of ²³²Th observed in zircon, rutile and garnet were 618, 454 and 64 Bq kg^?1, respectively. Concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K in ilmenite ore ranged from 17.6–444 Bq kg^?1, 80.4–1971 Bq kg^?1 and ≤5.5–25.0 Bq kg^?1, respectively.     

Natural radioactivity in granites and gneisses of the Opava Mountains (Poland): a comparison between laboratory and in situ measurements

The natural radioactivities of five characteristic igneous rocks of the eastern foreland of the Opava Mountains (Eastern Sudetes, Poland), obtained in the laboratory and under in situ conditions, are presented. The activity concentrations of ²³²Th, ²³⁸U, and ⁴⁰K were measured using an HPGe gamma-ray spectrometry system. The ranges of the activity concentrations of ²³²Th were 7–71 Bq kg^?1 in the laboratory and 6–68 Bq kg^?1 for the in situ measurements. For ²³⁸U, the ranges of the activity concentrations were 5–52 Bq kg^?1 in the laboratory and 9–48 Bq kg^?1 for the in situ measurements, and for ⁴⁰K, the ranges were 520–1560 Bq kg^?1 in the laboratory and 537–1700 Bq kg^?1 for the in situ measurements. These determined activity concentrations were compared with the average activity concentrations of the radionuclides in similar types of rocks and with data from the Sudetes available in the literature. No significant differences were found between the in situ and laboratory measurements.     

Evaluation of natural gamma radiation and absorbed gamma dose in soil and rocks of Perambalur district (Tamil Nadu,India)

The activity concentrations and absorbed gamma dose of primordial radionuclides ²³⁸U, ²³²Th and ⁴⁰K were determined employing γ-ray spectrometry in 31 soil samples from the land area earmarked for house construction in Perambalur district and 14 rock samples from quarries that supply stones for the entire district. The soil samples registered relatively a higher mean value of 13.2 Bq kg^?1 for ²³⁸U, 66 Bq kg^?1 for ²³²Th and 340.3 Bq kg^?1 for ⁴⁰K as compared to mean values for rock samples (²³⁸U—8.0 Bq kg^?1; ²³²Th—65.1 Bq kg^?1; ⁴⁰K—199.1 Bq kg^?1). The mean absorbed gamma dose rate for soil (61.4 nGy h^?1) marginally exceeded the prescribed limit of 55 nGy h^?1 while, rocks registered the mean absorbed gamma dose rate of 10.4 nGy h^?1. The mean radium equivalent activity was distinctly higher in soil (130.6 Bq kg^?1) than in rock (20.0 Bq kg^?1). However, these values were lower than the limit (370 Bq kg^?1) set by OECD for building materials. It is evident from the data that the soil and rocks do not pose any radiological risk for house constructions in Perambalur district.     

Natural radionuclides in Italian diet and their annual intake

This study was dedicated to the evaluation of the background activity concentration of natural radionuclides as ²²⁸Ra and ²²⁸Th of ²³²Th family, ²²⁶Ra of ²³⁸U family and ⁴⁰K in the Italian daily diet. These radionuclides were determined by gamma spectrometry. ⁴⁰K activity concentration, in the samples taken into account in the present paper, ranged between 70.5 (milk) and 181.1 Bq kg _ww ^?1 (pasta), ²²⁶Ra activity concentration ranged between 1.1 (milk) and 5.7 Bq kg _ww ^?1 (pasta), ²²⁸Ra and ²²⁸Th activity concentration, in the same samples, ranged between 0.7 (milk) and 3.7 Bq kg _ww ^?1 (pasta) and between 1.4 (milk) and 6.1 Bq kg _ww ^?1 (flours) respectively. The annual intake of every radionuclide from foodstuffs ingestion was also calculated. The 94–95 % of the total intake comes from ⁴⁰K. For adults and children, the highest activity intake of all radioisotopes was from grain products, for infants it was from milk products.     

Radioactivity in coffee

This research was dedicated to the study of the background levels of ²¹⁰Po and natural gamma emitters as ⁴⁰K, ²¹⁴Pb, ²¹⁴Bi, ²²⁸Ac, ²¹²Pb and ²¹²Bi in coffee powder and in coffee beverage; also the artificial ¹³⁷Cs was determined. In the coffee powder the mean ²¹⁰Po activity resulted 7.25 ± 2.25 × 10^?2 Bq kg^?1. ⁴⁰K showed a mean activity of 907.4 ± 115.6 Bq kg^?1. The mean activity concentration of ²¹⁴Pb and ²¹⁴Bi, indicators of ²²⁶Ra, given as mean value of the two radionuclides, resulted 10.61 ± 4.02 Bq kg^?1. ²²⁸Ac, ²²⁸Ra indicator, showed a mean activity concentration of 13.73 ± 3.20 Bq kg^?1. The mean activity concentration of ²¹²Pb, ²²⁴Ra indicator, was 8.28 ± 2.88 Bq kg^?1. ²⁰⁸Tl, ²²⁴Ra indicator, presented a mean activity concentration of 11.03 ± 4.34 Bq kg^?1. In all samples, the artifical ¹³⁷Cs resulted below the detection limit (2.0 Bq kg^?1). The arithmetical mean value of percentage of ²¹⁰Po extraction in coffee beverage resulted 20.5 ± 6.9. The percentage of transfer of gamma emitters,⁴⁰K, ²¹⁴Pb, ²¹⁴Bi, ²²⁸Ac, ²¹²Pb, ²⁰⁸Tl resulted of 80.0, 33.5, 24.7, 30.0, 35.1 and 53.5 % for ⁴⁰K, ²¹⁴Pb, ²¹⁴Bi, ²²⁸Ac, ²¹²Pb and ²⁰⁸Tl respectively.     

Measurement of gamma radiation from rocks used as building material in Tiruchirappalli district,Tamil Nadu,India

Tiruchirappalli district is naturally endowed with rich building material resources which are also used in neighboring districts. Hence, measurements of activity concentrations and absorbed dose rate of primordial radionuclides (²³⁸U, ²³²Th and ⁴⁰K) in the rock samples collected from 14 sedimentary rocks and 9 igneous rocks were carried out employing gamma ray spectrometry. In sedimentary rocks the geometric mean activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K were found to be 7.4, 29.5 and 233.6 Bq kg^?1, respectively. On the other hand in igneous rocks geometric mean activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K were distinctly higher and found to be 13.1, 105.7 and 888.8 Bq kg^?1, respectively. The mean radium equivalent activity (Ra_eq) recorded in both sedimentary (20.8 Bq kg^?1) and igneous rocks (245.4 Bq kg^?1) were well within the limit prescribed for dwellings (370 Bq kg^?1) except Vilathupatti (689.3 Bq kg^?1) and Narthamalai (371.6 Bq kg^?1). The mean absorbed dose rate from igneous rock (115 nGy h^?1) exceeded the prescribed limit of 55 nGy h^?1. The mean indoor annual effective dose from the sedimentary rock (0.056 mSv y^?1) and igneous rock (0.580 mSv y^?1) did not exceed the prescribed limit (1 mSv y^?1) except the igneous rock from Vilathupatti (1.51 mSv y^?1). The study concludes that sedimentary and igneous rocks analyzed were radiologically safe when used as building materials except igneous rock from Vilathupatti and Narthamalai.     

Assessment of natural and fallout radioactivity in soil samples of Visakhapatnam

Environmental gamma radiation levels around the new Bhabha Atomic Research Centre site at Visakhapatnam have been assessed. Natural and anthropogenic radionuclide activity concentrations in soil samples collected were determined using high-resolution gamma spectroscopy. Average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 38, 38, 230 and 520 Bq kg^?1, respectively. No anthropogenic radionuclide except fallout ¹³⁷Cs having mean concentration range ≤ 0.2–2.2 Bq kg^?1 was detected in the soil samples. The observed values are compared with the values reported for different areas in India and other parts of the world. The annual total external gamma radiation dose to the members of public estimated using the above observations ranged from 0.13 to 0.38 mSv y^?1 with an average of 0.25 mSv y^?1.     

Dose rates and seasonal variations of 238U, 232Th, 226Ra 40K and 137Cs radionuclides in soils along Thrace, Turkey

Concentrations of ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs are measured in collected soil samples from various locations in the Thrace region of Turkey. The activity concentrations range from 12.82 to 101.75 Bq kg^?1 d.w. (dry weight) for ²³⁸U, from 5.16 to 73.34 Bq kg^?1 d.w. for ²³²Th, from 185.54 to 5399 Bq kg^?1 d.w. for ⁴⁰K and from 11.42 to 90.73 Bq kg^?1 d.w. for ²²⁶Ra. In addition to naturally occurring radionuclides, ¹³⁷Cs activity concentration is determined between 3.05 and 46.78 Bq kg^?1 d.w. for soil samples. Determination of the radiological hazard is achieved through calculations of the external terrestrial gamma dose rate in air (nGy h^?1) and annual effective dose rate (mSv year^?1) and the results are compared with the similar works in different countries.     

A preliminary study on 226Ra, 232Th, 40K and 137Cs activity concentrations in vegetables and fruits frequently consumed by inhabitants of Elazığ Region, Turkey

Determining radioactivity levels in foodstuffs is of great importance for the protection of human health. In addition, the literature includes few studies related to this subject in Turkey. In this study, gamma spectroscopic system was used in order to measure ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs activity concentrations in vegetables and fruits produced in Elaz?? Region. The average activity concentrations in vegetables was calculated as 0.64 ± 0.26 Bq kg^?1 for ²²⁶Ra, 0.65 ± 0.14 Bq kg^?1 for ²³²Th, 13.98 ± 1.22 Bq kg^?1 for ⁴⁰K, and 0.54 ± 0.04 Bq kg^?1 for ¹³⁷Cs. The average activity concentrations in fruits were 1.52 ± 0.34, 0.98 ± 0.23, 18.66 ± 1.13 and 0.59 ± 0.16 Bq kg^?1, respectively for ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs. Total committed effective dose value was determined as 20 and 30.55 μSv y^?1, respectively for vegetables and fruits. The findings were compared with previous data reported for Turkey and other regions of the world.     

Terrestrial gamma exposure in the granodiorite area of Bergama (Pergamon)�CKozak, Turkey

As higher radiation levels are associated with granite and Bergama (Pergamon) has increasingly become a large market for granite use over the last years, an extensive investigation was started in 2009. Samples from the granites and soils underlying this area were collected and analyzed by HPGe gamma spectrometry system. The specific activities of the naturally occurring radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be in the range of 29?C111 Bq kg^?1 for ²²⁶Ra, 35?C87 Bq kg^?1 for ²³²Th and 698?C1100 Bq kg^?1 for ⁴⁰K in granite samples. The ranges of ²²⁶Ra, ²³²Th, and ⁴⁰K activity concentrations for soils were 32?C82, 42?C88 and 667?C1127 Bq kg^?1, respectively. From these data radiological parameters were calculated and compared with respective data from the UNSCEAR reports.     

Gamma background measurements in the Gran Sasso National Laboratory

In situ gamma-ray measurements were taken at eight locations in the Gran Sasso National Laboratory (Italy). Count rates for gamma radiation within the energy range of 7–2,734 keV varied from 8 to 60 γ s^?1. The arithmetic mean was 49 γ s^?1 for measurements taken without a collimator. The average gamma flux inside the Lab was 0.25 γ cm^?2 s^?1. The sedimentary rocks surrounding the Lab are characterized by low activity concentrations of uranium and thorium, equal to 1.7 and 1.4 Bq kg^?1, respectively.     

Radioactivity levels and radiation hazard of healing mud from San Diego River, Cuba

Healing mud core samples were collected in the San Diego River (Southwest Cuba), in order to determine the behaviour of the radioactivity levels of ²²⁶Ra, ¹³⁷Cs, ²³²Th and ⁴⁰K and to evaluate their possible radiological impact on peloide therapeutic uses. The radionuclide concentration ranges in healing mud profiles on Bq kg^?1 dry weight varied as follows: ²²⁶Ra = 22–26, ¹³⁷Cs = 4.6–33.0, ²³²Th = 18–31 and ⁴⁰K = 208–433. The calculated average radium equivalent activity (82 Bq kg^?1), total absorbed dose rate (40 nGy h^?1), external hazard index (0.23), annual gonadal dose equivalent (280 μSv h^?1) and annual effective dose equivalent (48.5 μSv y^?1) are less than international recommended values. Hence, the levels of radioactivity in healing muds from San Diego River are not an impediment for its use for medical proposes.     

137Cs, 40K, alkali–alkaline earth element and heavy metal concentrations in wild mushrooms from Turkey

In 2002, an extensive study was performed in forest sites of Izmir. This first study results led on the one hand, to quantify of ¹³⁷Cs and ⁴⁰K concentration in mushrooms collected in the Izmir region and to a first evaluation of dose in people due to the ingestion of radionuclide-contaminated mushrooms. The mushroom concentration values varied over a wide range from below detection limit to 401 ± 4 Bq kg^?1 (dry wt) for ¹³⁷Cs. The ⁴⁰K concentration values obtained for different species of mushrooms ranged from 588 ± 26 Bq kg^?1 to 2024 ± 63 Bq kg^?1 (dry wt). The annual effective dose values due to mushroom ingestion for ¹³⁷Cs are lower than the ICRP-2007’s reference level value of 1 mSv for “existing” exposure situation. Inductively coupled plasma-mass spectrometry was used to measure many alkali–alkaline earth elements and heavy metals in mushroom samples. The relationships among the concentrations of ¹³⁷Cs and the stable elements were presented and the occurrence of metals in mushrooms was evaluated.     

Natural radioactivity studies of Bidar soil samples using gamma spectrometry

The activity of the terrestrial primordial radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K are measured for Bidar soil samples. The collected soil samples are analyzed using HPGe detector based on high resolution gamma spectrometric system. The activity of the three radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K were found to be in the range of BDL–47.68, 7.65–59.08 and BDL–260.65 Bq kg^?1 respectively. The mean gamma absorbed dose rate in air above 1 m from ground is estimated to be 34.47 nGy h^?1. Annual effective dose equivalent and the radium equivalent activity were within the limits in the present study and it is found that the activity of the radionuclides are comparable with the worldwide literature values. Also the external hazard indices for the soil samples of Bidar district were within the limit of unity.     

Measurement of natural radioactivity and radiation hazards for some natural and artificial building materials available in Romania

As building materials are known to be the second source regarding high radon concentrations, it is very important to determine the amounts of natural radionuclides from every building material in use. In the present study the most frequently used Romanian natural (sand, gypsum, limestone) and artificial (portland cement, lime, clinker, electrofilter powder, fly ash, cement-lime plaster mortar, cement plaster mortar) building materials were analyzed. The absorbed dose rate and the annual effective dose equivalent rate for people living in dwelling buildings made of these building materials under investigation were also calculated. The analysis was performed with gamma-ray spectrometry, with two hyper-pure germanium detectors. The activity concentrations of natural radionuclides were in the ranges: 5.2–511.8 Bq kg^?1 for ²²⁶Ra; 0.6–92.6 Bq kg^?1 for ²³²Th and <1–1,720.7 Bq kg^?1 for ⁴⁰K, respectively. The radium equivalent activity in the fifty-one (51) samples varied from 9 to 603 Bq kg^?1. By calculating all the radioactivity indices (Ra_eq, H _ext, I _α, I _yr) it was found that all the building materials under investigation can be used to erect dwelling buildings. Except for sample SA6, SA7 and SA11 among the natural building materials and sample SG1, SG2, FAH1, CLM1, CM1 among the artificial building materials that are considered hazardous materials when are used in large quantities.     

Radiometric analysis of rock and soil samples of Leepa Valley; Azad Kashmir, Pakistan

In this article, we present results obtained from a radiometric survey that was conducted in the Leepa Valley of Azad Jammu & Kashmir, Pakistan. The purpose of current study is to appraise the radioactivity levels and the associated health hazards due to the terrestrial radionuclide in soil and rock samples. In this regard, 16 soil and 17 rock samples were collected from different locations of the Leepa Valley. After processing the samples, activity concentrations of primordial (²³²Th, ²²⁶Ra and ⁴⁰K) and anthropogenic (¹³⁷Cs) radionuclides were determined using a P-type coaxial high purity germanium detector. From the results obtained the mean activity concentrations of radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in the soil samples were found to be 31.25 ± 0.46, 44.1 ± 1.07 and 575 ± 8.89 Bq kg^?1 respectively. Whilst, in rock samples ²²⁶Ra, ²³²Th and ⁴⁰K mean activities were found as 28.46 ± 0.45, 48.63 ± 1.12 and 666.7 ± 9.39 Bq kg^?1, respectively. The ¹³⁷Cs concentration level in soil and rock samples is found to be 15.04 ± 0.29 and 5.7 ± 0.16 Bq kg^?1, respectively. The average radium equivalent activity (R _aeq) was found as 143.16 and 142.93 Bq kg^?1 in soil and rock samples, respectively. These findings are less than the recommended safe value of 370 Bq kg^?1 as given in OECD report (1979). The values of external (H _ex) and internal hazard index (H _in) are also less than unity. Mean value of absorbed dose rate was found as 69.78 nGy h^?1 for the soil samples, which is in good agreement with the world wide average value (70 nGy h^?1). Mean value of absorbed dose rate from rock samples was found as 70.01 nGy h^?1. Mean values of the annual effective dose is also lower than the values reported for different other countries of the world.     

Determination of plutonium-239,240 in environmental samples from surroundings of the Atomic Power Station Jaslovské Bohunice

Specific activity of^239,240Pu in contaminated soils from the bank of Manivier channel was determined to be in the range of 5–40 Bq·kg^?1 and for soils from the bank of Dudvah river 0.6–8 Bq·kg^?1. The ratio of^239,240Pu/¹³⁷Cs found in the samples is about 1·10^?4, which is very close to the ratio found in the pulp of high activity concentrate in the collecting tank of nuclear power plants (NPP).