Average Concentrations Of 226Ra Research Articles

Lifetime Cancer Risk of Gamma Radioactivity Results from Smoking

Smoking is one of the causes of heart attack, lung cancer and cancers of mouth and larynx. The latter could be arises from exposure of those sensitive organs to a combination of both chemical carcinogenic and radiological exposure results from naturally occurring radionuclides in tobacco leaves. Coal is also used in smoking some types of tobacco products that could be carcinogenic due to presence of a high percentage of an organic matter with inorganic matter such as minerals and trace elements. Varieties of commonly available tobacco products as well as coal samples were examined for their radioactivity content using gamma ray spectroscopy and calculate associated radiological hazards. Results shows that the average concentrations of 226Ra, 232Th, and 40K in tobacco samples vary from 2.6±0.2 to 8.9±0.7 (average 5.4), 1.9±0.1 to 9.5±0.8 (average 4.5), and 517.4±15.5 to 2401.2±72 (average 1360.4) Bqkg-1. Measured activity concentration for coal samples ranged from 10.8±1.1 to 64.4±2.1 (average 40.2), 3.5±0.1 to 28.3±0.3 (average 15.7), and 49.2±0.4 to 301.2±9.5 (average 215) Bqkg-1 for 226Ra, 232Th, and 40K respectively. 137Cs activity concentrations in cigarettes and coal samples were ranged from 0.1±0.01 to 1.3±0.02 (average 0.5) and 2±0.01 to 5.8±0.8 (average 3.1) Bqkg-1 respectively. Radium equivalent, total annual effective dose and excess lifetime cancer risk were calculated. ELCR was higher than world's average of 1.45x10-3 for tobacco and coal samples. In Egypt no special and clear regulations for monitoring radioactivity content in imported coal and tobacco leafs or its products, which appear to be necessary.

Factors controlling 226Ra, 228Ra and their activity ratio in groundwater – an application in Polish Carpathian mineral waters

The influences of aquifer formations and water chemical composition on the occurrence and activity ratio of radium isotopes in groundwater are discussed. Based on the model of desorption/adsorption processes of natural radionuclides in the rock-water system, the concentrations of radium isotopes and their activity ratio in groundwater are evaluated by the numerical Monte Carlo method (MC). In cases where the groundwater is of a similar age, limited flow (up to several meters/year), the physical conditions and the uranium and thorium activity ratios in host water formations are similar, the activity concentrations of radium isotopes (226Ra, 228Ra) and their activity ratio (226Ra/228Ra) are the highest in the water of high desorption coefficient for chloride sodium water (domination of Cl− , Na+ ions), medium in water of moderate desorption (bicarbonate water – HCO3 − , Ca2+) and the lowest in waters with a low desorption coefficient (sulfate ions prevailing – SO4 2−, Ca2−). The statements are well confirmed in the case of the natural mineral waters from the Polish Outer Carpathians. The total dissolved solids (TDS) of the Polish Carpathians waters varies from several hundred milligrams per liter to several tens of thousands milligrams per liter. The minimum, maximum and average concentrations of 226Ra, 228Ra and their activity ratio (226Ra/228Ra) are 82, 1340, 456 mBq/L, 19, 1240, 354 mBq/L and 0.89, 7.6 and 2.0 for chloride waters; 4, 140, 45.8 mBq/L, 12, 171, 62.7 mBq/L and 0.3, 1.7 and 0.70 for bicarbonate waters and 0.8, 9.3, 3.6 mBq/L, 5.3, 54, 20.1 mBq/L and 0.1, 1.0, 0.3 for sulfate ones, respectively. The desorption coefficients are the highest for the Cl-Na, moderate for the HCO3-Ca and the lowest for the SO4-Ca waters (in contrast to the adsorption properties of these waters).

The Measurements of Natural Radioactivity, (Radon and Gamma concentrations), around the old fertilizer factory in Basrah/Iraq

Radon concentration, exhalation rate, annual effective dose, radium activity, thorium, uranium potassium and radium equivalent have been measured in the present investigation for soil in the area around the old fertilizer factory in southern of Basrah Governorate. The measurements based on CR39 track detector for passive method, RAD7 for active method and NaI(Tl) for gamma concentration measurements. Average values for radon concentration in soil were 112.04±10.76 Bq/m3 using passive technique and 104.56±6.05 Bq/m3 using RAD7. From the result of the passive technique, area and mass exhalation rates and the annual effective dose were calculated. Gamma ray spectroscopy for the soil samples were performed and found that the average concentrations of 226Ra, 232Th and 40K were 50.89 Bq/kg, 21.74 Bq/kg and 640.4 Bq/kg respectively. Gamma ray hazard indices were calculated and found they are within the world average.

Evaluation of excessive lifetime cancer risk due to natural radioactivity in the rivers sediments of Northern Pakistan

Naturally occurring radionuclides 226Ra, 232Th and 40K present in the rivers sediments of Northern Pakistan were measured using HPGe γ-ray spectrometer to evaluate the radiation health hazard indices and excess lifetime cancer risk (ELCR). Average concentrations of 226Ra, 232Th and 40K in the sediments were found to be 50.66 ± 1.29, 70.15 ± 1.45 and 531.70 ± 5.45 Bq kg−1 respectively. Radium equivalent activity (190.89 Bq kg−1), outdoor external dose (87.47 nGy h−1), indoor external dose (165.39 nGy h−1), and total average annual effective dose (0.92 mSv) were calculated. The hazard indices are higher than the world's average values. Total excess lifetime cancer risk (ELCR) was found to be 3.21 × 10−3 which is relatively higher. Numerous cancer deaths are annually reported from the Northern areas of Pakistan, which may be related to high radioactivity in the area.

Estimates of the occupational exposure to tenorm in the phosphoric acid production plant in Iran

Phosphate rock is used world wide for manufacturing phosphoric acid and several chemical fertilisers. It is known that the phosphate rock contains various concentrations of uranium, thorium, radium and their daughters. The subject of this study is the evaluation of the radiation exposure to workers in the phosphoric acid production plant due to technologically enhanced naturally occurring radioactive materials that can result from the presence of naturally occurring radioactive materials in phosphate ores used in the manufacturing of phosphoric acid. Radiation exposure due to direct gamma radiation, dust inhalation and radon gas has been investigated and external and internal doses of exposed workers have been calculated. Natural radioactivity due to (40)K, (226)Ra and (232)Th have been measured in phosphate rock, phosphogypsum, chemical fertilisers and other samples by gamma spectrometry system with a high-purity germanium. The average concentrations of (226)Ra and (40)K observed in the phosphate rock are 760 and 80 Bq kg(-1), respectively. Annual effective dose from external radiation had a mean value of ∼0.673 mSv y(-1). Dust sampling revealed greatest values in the storage area. The annual average effective dose from inhalation of long-lived airborne was 0.113 mSv y(-1). Radon gas concentrations in the processing plant and storage area were found to be of the same value as the background. In this study the estimated annual effective doses to workers were below 1 mSv y(-1).

Elements of Natural Radioactive Decay Series in Iranian Drinking Water and Cigarettes

The uranium (238U) decay series provides the most important isotopes of elements radium (226Ra), radon (222Rn), and polonium (210Po) with half-lives of about 1600 years, 3.8 days, and 140 days, respectively. Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. In this study, we used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose. In the other part of the study, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the lung tissues of smokers. The results indicate that the average concentration of 226Ra in Iranian drinking water was below the 100 mBq L(-1) recommended by the World Health Organization while the average concentration of 210Po and 210Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market.

Activity concentration of radium-226 in agricultural soils

Fourty two soil samples were collected to a depth of 20 cm from the Aegean Region of Turkey. The activity concentrations of 226Ra in the samples were determined by a radioanalytical method. The radiochemical yield for pure 226Ra was found to be 90.02±2.74%. The average concentration of 226Ra was 0.150 Bq.g-1 and its distribution fitted a normal curve. The average absorbed dose rate was found to be 61 nGy.h-1. The data were evaluated to explain of 226Ra distribution in the agricultural area and compared with other results in the literature.

Natural radionuclides contents and radon exhalation rates in building materials used in South Korea.

The natural radionuclide (226Ra, 232Th and 40K) contents of building materials commonly used in South Korea have been determined by a gamma ray spectroscopy system using a high purity germanium detector. The radon exhalation rates and emanation coefficients of building materials have also been studied. The average concentrations of 226Ra, 232Th and 40K in building materials were in the range of 6.47-271 Bq.kg-1, N.D.-89.9 Bq.kg-1 and 16.8-1081 Bq.kg-1, respectively. The average radon exhalation rates and emanation coefficients were in the range of 0.0061-0.2404 Bq.kg-1.h-1 and 2.39-11.5%, respectively.

Distribution of 226Ra, 232Th, and 40K in soils of Rio Grande do Norte (Brazil)

A survey programme aimed at studying the environmental radioactivity in the Brazilian state of Rio Grande do Norte was undertaken. Fifty-two soil samples, together with two rock and two uraniferrous ore samples were collected from the eastern and central regions of this state. Concentrations of radioelements in samples were determined by γ-ray spectrometry. The average concentrations of 226Ra, 232Th, and 40K in the surveyed soils were 29.2 ± 19.5 (SD), 47.8 ± 37.3, and 704 ± 437Bq kg −1, respectively. Higher values were found in the rock samples. The distributions of 226Ra and 232Th were fitted by log-normal curves. Radiological measurements carried out with a portable scintillometer at the sampled sites revealed an average absorbed dose rate of 55 ± 27 (SD) nGy h −1. Computed dose rates obtained through the Beck formula ranged from 15–179nGy h −1, with a mean value of 72.6 ± 38.7 (SD) n Gyh −1, and their distribution fitted a log-normal curve. An annual average effective dose equivalent of 552 μSv (range: 117–1361 μSv) was estimated for 51 sites in Rio Grande do Norte.

Soil characterization for indoor radon potential at eighteen schools in New York State

During the two school years between 1991 and 1993, 60 schools were measured for indoor radon in New York State. Schools were solicited from areas considered to be at risk for above-average indoor radon based on residential indoor radon measurements and on the geology of the area. Eighteen of the sixty schools participating in the New York State study were selected for soil-radon potential characterization. Soils near the perimeter of the school, in the school yard, and in crawl spaces were measured for soil 226Ra concentration, soil-gas 222Rn concentration, and permeability for gas flow. In general, above-average indoor radon concentrations in the schools were found to correlate with highly permeable, gravelly soils. At 10 schools, the average soil permeability for gas flow was greater than 3 × 10 −10m 2 for each school, and 47% of the rooms tested in these 10 schools had long-term indoor radon concentrations greater than 150 Bq/m 3. The soils near the 10 schools were generally glacial outwash gravel deposits containing average concentrations of 226Ra and soil-gas 222Rn.

Radioactivity levels in jurak and moasel, comparison with cigarette tobacco

Jurak and moasel are tobacco products that contain, in addition to tobacco, juice of sugar cane, fruits, spices, tar and nicotine. These products are smoked by hubble-bubble, a popular smoking habit in the Middle Eastern and North African countries. Charcoal is put directly on these products during smoking and the smoke passes through water for cooling purpose before it goes to the lung, without filtering. Radioactivity levels were measured in these products, tobacco leaves, charcoal and in cigarette tobacco of most well known brand names by gamma spectrometry system consisting of HPGe detector coupled to a PC-based 8192 channel multichannel analyzer. The average226Ra concentrations in jurak, moasel, tobacco leaves, charcoal and cigarette tobacco in Bq/kg were: 3.4, 1.8, 3.2, 2.9 and 7 respectively; that of232Th were: 3.8, 2.6, 3.5, 2.2 and 7.8 respectively; that of40K were 620, 445, 511, 163 and 876 respectively. It is expected that a jurak smoker inhales 10 times the radioactivity and a moasel smoker twice that compared to a 25 cigarette/d smoker.

Assessment of the natural radioactivity in the Brazilian state of Rio Grande do Norte.

Fifty-one soil samples were collected to a depth of 30 cm in the central and eastern region of the Brazilian state of Rio Grande do Norte. Concentrations of background radionuclides in soil samples were determined by gamma ray spectrometry with an HPGe detector. The average concentrations of 226Ra, 232Th, and 40K in the surveyed soils were 29.0 +/- 19.4 Bq kg-1, 46.6 +/- 36.2 Bq kg-1, and 677.8 +/- 434.9 Bq kg-1, respectively. The bedrock of Santana do Matos (Rio Grande do Norte) showed fairly high radioactivity (90 Bq kg-1 of 226Ra, 285.6 Bq kg-1 of 232Th, and 1,414 Bq kg-1 of 40K). Radiological measurements carried out in Santana do Matos with a hand-held scintillometer revealed external gamma radiation ranging from 200-330 nGy h-1 in the down-town area. Higher values were recorded in the surroundings of that town.

Local Distribution and Dosimetry of 226 Ra in the Trabecular Skeleton of the Beagle

Young adult beagle dogs received a single injection of 38.1 kBq/kg body wt 226Ra and were serially sacrificed at 4 to 2955 days postinjection. Samples of sites of trabecular bone in the lumbar vertebral body, proximal ulna, and distal femoral metaphysis and epiphysis were analyzed autoradiographically. The time-dependent changes in the average 226Ra concentrations in the four regions were analyzed in terms of a compartmental model. The clearance rate from the lumbar vertebral body was about four times more rapid than for the proximal ulna and distal femoral epiphysis. Ratios of hotspot to diffuse label concentrations varied from about 10 to 23. The dose rate to the endosteum ranged between 8.7 and 39.5 mGy/day initially and 4 and 10.5 mGy/day toward the end of the observation period. Mean marrow dose rates were lower by a factor of 3 to 9.5. During their residence time the nuclei of bone lining cells receive a maximum dose of 8 Gy in the proximal ulna (2955 days after injection) and a minimum dose of 0.63 Gy in the lumbar vertebra (2955 days after injection). This corresponds on the average to 17 and 1.4 alpha-particle hits to the cell nuclei, respectively.