Natural and fallout radioactivity measurement in Indian soils

The paper presents the results of high resolution gamma-spectrometric measurements of ¹³⁷Cs, ⁴⁰K, ²³²Th and ²³⁸U in Indian soils collected from 24 different places from normal natural radiation background areas. The depth profile of ¹³⁷Cs was studied at sampling sites. The paper also presents ¹³⁷Cs levels in top soil at Mumbai during 1986 to 2000. The results in Mumbai soil indicate clearly the accumulation from fallout only on the top soil and seasonal peaking during the beginning of the monsoon season.     

The use of INAA technique in provenance studies of ancient pottery from the Greater Accra region of Ghana

The field of Archaeological in Ghana has been in existence for a very long time, gaining respect in some areas in the West African sub-region. The history of some early societies in Ghana with relation to pottery making and its uses still has a lot to be discovered. Provenance or source analyses are vital in exchange studies by finding the sources of artifacts. Through characterization studies, archaeological materials can be shown to have originated from particular areas enabling archaeologists to demonstrate human interaction. The Ga (Ayawaso) and the Dangme-Shai had cultural contacts and trade with neighboring towns and with the various European factors that traded in the coasts of Accra. The archaeological material remains recovered from these communities (Ayawaso, Wullf and Shai) during excavation were investigated using Scientific Nuclear Analytical technique. In all, the concentrations of 15 trace elements (i.e. Ce, Co, Cr, Eu, Fe, Hf, La, Lu, Mn, Rb, Sc, Ta, Tb, V, Yb) were determined in 40 pottery samples and clay samples from Afuamang (Ayawaso) and Doryumu (Shai) using instrumental neutron activation analysis (INAA). Raw clay samples from Doryumu and Afuamang normalized perfectly with pottery samples from the Shai and Ayawaso Township, respectively. Pottery samples from Wullf also normalized well with clay from Afuamang than it did with those from Doryumu. This is construed that the Wullf community did not produced their own pots but traded more with the potters from Ayawaso which was the closest potting town.     

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.     

Natural radioactivity and their radiological effects for different types of rocks from Egypt

The present work investigated the radioactivity level of the rocks samples collected from different sites in Egypt. Twenty one rocks samples were analyzed by gamma-ray spectrometry using NaI(Tl) detector with specially designed shield. The concentration of three natural radionuclides namely ²²⁶Ra, ²³²Th and ⁴⁰K has been determined and compared with chemical data obtained by XRF analysis. The results showed that these radionuclides were present in concentration ranges (3.4-99, 7.5-134 and 93-3382 Bq kg⁻¹), (54.9-211.6, 20.71-170.5 and 2068-2344 Bq kg⁻¹) and (13-106, 29.25-106.1 and 682-755 Bq kg⁻¹) for gneiss, granite and basalt rocks, respectively, while the values were (7.5, 12.5 and 263.9 Bq kg⁻¹) and (113, 148.5 and 1672 Bq kg⁻¹) for ²²⁶Ra, ²³²Th and ⁴⁰K in sandstone and siltstone rocks, respectively. Also radium equivalent activity, total dose rates and external hazard index of the rocks samples under consideration were calculated. The results showed that granite rocks contain a high proportion of natural radioactive elements, while sandstone rocks have lesser radioactivity concentration compared with other types of rocks.     

Natural and artificial radioactivity levels of greenhouse soils and relations with soil properties

Journal of Radioanalytical and Nuclear Chemistry - In this study, natural (226Ra, 232Th, 40K) and artificial (137Cs) radionuclide activity concentration levels of 63 greenhouse soils collected from...     

Natural radioactivity levels of limestone rocks in northern Iraq using gamma spectroscopy and nuclear track detector

The activity concentration of radionuclides, such as ²³⁸U, ²²⁶Ra and ⁴⁰K of limestone rocks in northern Iraq was measured using gamma spectroscopy. The radionuclide activities were obtained and discussed. CR-39 nuclear track detector was used to measure the radon exhalation rates as well as the effective radium contents of these samples and are found to correspond with uranium concentration values measured by NaI(Tl) detector in the corresponding limestone rocks samples. The absorbed gamma dose rates in air due to the presence of ²³⁸U, ²²⁶Ra, ⁴⁰K and cosmic ray contribution varied between 105.3 and 223.11 nGy/h. The annual effective dose of each sample has been calculated. The correlation between activities of ²²⁶Ra, ²²²Rn exhalation rates and ²³⁸U is explained. Results show a symmetrical distribution of activity concentrations of primordial of radionuclides in selected samples. The values of all studied radionuclides are considered to be a typical level of natural background and compared with results of similar investigations carried out else where.     

Natural radioactivity and radiological hazard evaluation in surface soils at the residential area within Ban Gie monazite placer,Nghe An

Journal of Radioanalytical and Nuclear Chemistry - 226Ra, 238U, 232Th(228Ra), and 40K activities of 51 surface soils samples at Ban Gie monazite placer, Vietnam were measured by HPGe detector. The...     

Natural radioactivity and radiological implications of granite rocks,El-Sela area,Southeastern Desert,Egypt

Journal of Radioanalytical and Nuclear Chemistry - In the present study, the 238U and 232Th radioactivity afford a perfect indication of the attendance of heavy minerals. Herein, integrated ground...     

Natural radioactivity of building materials

Experiments were designed to measure trace uranium concentration and the rate of radon exhalation from masonry structural materials, both bare and surface finished and coated. LR115 cellulose nitrate track detectors were used to record the alpha emission from structural material surface. Fission track, neutron activation and fluorometric analysis methods were used to determine the uranium content. Most types of paints studied will reduce alpha contribution and radon emanation from building materials.     

Changes in radioactivity of phosphate rocks during the process of production

A gamma-spectrometric method has been developed for the determination of radioactivity of phosphate rocks, products and residues of technologies. After discussing an introduction of the phosphate processing technology, the experimental results concerning U, Th and their daughter elements and⁴⁰K are presented. Furthermore, the results of investigations on the assay of radon are summarized.     

Natural radioactivity in Algerian bottled mineral waters

The activity concentrations of some radionuclides in Algerian bottled mineral waters were determined using CR-39 nuclear track detectors for ²²²Rn, and a high resolution gamma-ray spectrometry for ²²⁶Ra, ²³²Th and ⁴⁰K. The mean specific activities of ²²²Rn , ²²⁶Ra, ²³¹Th and ⁴⁰K in the drinking mineral waters were 7±4 Bq^.l^-1, 26±11 mBq^.l^-1, 30±13 mBq^.l^-1 and 1±0.5 Bq^.l^-1, respectively. These values are comparable with concentrations reported for other countries. The effective doses due to intake of these radionuclides as a consequence of direct consumption of drinking mineral waters have been determined. The estimated effective doses were 56.8 mSv^.y^-1 for ²²²Rn, 3.94 mSv^.y^-1 for ²²⁶Ra, 4.45 mSv^.y^-1 for ²³²Th and 3.33 mSv^.y^-1 for ⁴⁰K. Contribution of these radionuclides to the effective dose due to ingestion and inhalation of all terrestrial radionuclides is estimated to be only 0.012%.     

Natural radioactivity in bioassay by alpha-spectrometry measurements

Personnel of nuclear facilities are checked regularly for internal contamination by bioassay measurements. Although these persons are generally not involved in any incident, natural radioactivity from U, Th and Ra can be found in their urine or faeces. Uranium total activity in urine has been found with a range of 0.051 to 3.0 mBq/24 h and in faeces from 14.5 to 380 mBq/d. ²³⁴U/²³⁸U ratio for urine is 1.48 but this ratio varies from 0.47 to 19. By comparison, the ²³⁴U/²³⁸U ratio found in urine from workers in volved with natural uranium or 4.5% enriched uranium is 1.0 and around 4.0 respectively. ²³⁰Th, ²²⁸Th and sometimes ²³²Th have also been detected. The total thorium activity varies from 0.137 to 5.6 mBq/24 h in urine and from 9 to 183 mBq/d in faeces. ²²⁸Th has generally been found in excess of ²³²Th. All these measurements were performed by alpha-spectrometry. The few ²²⁶Ra results have been measured using the Lucas or emanation method.     

Natural radioactivity of Zambian coal and coal ash

²²⁶Ra and²³²Th specific activities in coal from Maamba Collieries in Zambia have been measured at 46±8 and 56±9 Bq kg^–1, respectively. These values are nearly two and a half times larger than the world average for coal and are close to those for lignite or brown coal. Determination of specific activities in coal waste at Maamba and coal ash at the fertilizer factory in Kafue showed enhancement factors of 2.6 and 2.0, respectively. These values are well within the world range of enhancement factors in coal ash.     

Preliminary studies on 222Rn concentration in ground water from selected areas of the Accra metropolis in Ghana

Preliminary studies on groundwater samples from selected wells in three communities in the Greater Accra region of Ghana have been carried out to determine the concentration of ²²²Rn. The studies were carried out in the dry season when the weather conditions were fairly stable and the communities depend mostly on groundwater sources for domestic use during this period. Measurements were carried out using gamma spectrometry. The average activity concentration obtained was 8.1 Bq/L with an average annual effective dose of 59.2 μSv. The result is within the range published by other countries and the recommended limit for radon in drinking water set by the World Health Organization.     

Natural radioactivity in the Guadalquivir river at the South of Spain

U, Th and Ra isotopic activities have been measured in water and sediment samples collected over three years from the Guadalquivir river channel (South of Spain). The study of the radioactivity levels and activity ratios evolution in space and time has provided information on the behavior of the radionuclides mentioned above in the estuarine and non-estuarine zones of the river.     

Natural radioactivity in building materials utilized in the State of Kuwait

A simple radiochemical procedure is described for the determination of⁹⁰Sr in brines, which are very highly concentrated in sodium, calcium, potassium, magnesium, chloride and sulfate ions. The method is based on the different solubility of yttrium as compared to that of strontium, calcium and magnesium in ammonium chloride solutions, and utilizes Eichroms resin TRU·Spec for the purification of the yttrium fraction. The overall time required for the⁹⁰Sr analysis (excluding the counting time) is less than one day. Because the procedure involves only rather simple steps, it is well suited for routine analyses of large sample numbers.     

Natural radioactivity and hazard-level assessment of Portland cements in Turkey

The natural radioactivity levels and some radiological parameters of Turkish Portland cements (PC) originated in various regions were determined in this study. The activity concentration of cement samples for ²²⁶Ra, ²³²Th, and ⁴⁰K were measured using a gamma-ray spectrometer with high purity germanium radiation detector. The PC samples had activity concentrations of 33.0, 16.7, and 239.5 Bq kg⁻¹ for ²²⁶Ra, ²³²Th, and ⁴⁰K, respectively. The mean value of radium equivalent value (Ra_eq) was found to be 75.4 Bq kg⁻¹. The radium equivalent values in the cement samples were lower than the acceptable level of 370 Bq kg⁻¹. The calculated radiological parameters were found to be below the acceptance levels.

     

Natural radioactivity of geothermal water in Beijing,China

In this work, we collected 101 geothermal water samples to investigate comprehensively the radioactivity of geothermal water in Beijing. The concentrations of gross beta, ²²⁶Ra and ²²²Rn were measured and the obtained values were in the range of 0.032–7.060, 0.023–0.363 and 0.470–29.700 Bq/L, respectively. The samples with higher concentration of ²²²Rn were found to be located near large faults. The effective dose of ²²²Rn in the air for three cases were calculated to be greater than radiation dose limit of 1 mSv/a.