Browsing by Subject "NATURAL RADIOACTIVITY"

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    Radon Exhalation Rate from Building Materials Using CR-39 Nuclear Track Detector
    (SAGE PUBLICATIONS LTD) Topçu, N; Biçak, D; Çam, S; Erees, FS
    Humans are exposed to radiological hazards from natural radiation sources that exist mainly in the earth's crust. Radon is a noble gas and is formed by the decay of Ra-226, which is one of the nuclides formed in the disintegration series from U-238. Building materials are considered as one of the major sources of radon in the indoor environment. Radon is one of the indoor sources that cause radiological health risk. To study radon exhalation rate, samples of sand, gravel, stone, cement, granite, marble, ashlar, ceramic tile and bricks were collected from Manisa and Izmir provinces of Turkey. The radon exhalation rates (in terms of mass and surface area) for these materials were also calculated by using solid-state nuclear track detector (CR-39). The mass and surface exhalation rates are calculated by following the radon activity growth as a function of time. These values were also compared with literature values.
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    Determination of radioactivity levels in Akhisar, Gordes, Golmarmara and Sindirgi regions, Western Turkey
    (SPRINGER) Kaynar, SÇ; Saç, MM; Erees, FS
    In this study, radioactivity measurements in the environment of Akhisar, Golmarmara, Gordes 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 K-40, U-238 and Th-232 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 K-40, U-238 and Th-232 in soils ranged 2.80-2,347.77, 9.90-256.19 and 9.66-106.53 Bq kg(-1), respectively. The activity of Ra-226 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.
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    Environmental Radioactivity and High Incidence Rates of Stomach and Esophagus Cancer in the Van Lake Region: A Causal Relationship?
    (ASIAN PACIFIC ORGANIZATION CANCER PREVENTION) Akan, Z; Baskurt, B; Asliyuksek, H; Kam, E; Yilmaz, A; Yuksel, MB; Biyik, R; Esen, R; Koca, D
    This study examined the incidence rates of cancer cases (averages for 2006-2010) and relationships with environmental radioactivity levels. Soil and water samples were collected from provincial and district centers of Van city and the outdoor gamma doses were determined using a portable gamma scintillation detector. Gross alpha and beta, (226)Ra, (232)Th, and (40) K activities were measured in both tap water and soil samples. Although high rates of stomach and esophagus cancers have been reported previously in Van the underlying reasons have not hitherto been defined. Incidences of cancers were highest in the Gurpinar (326.0) and Ozalp (377.1) counties (p<0.001). As to the results of the gross alpha and gross beta radioactivity measurements in the drinking water, these two counties also had high beta radionuclide levels: Gurpinar (140 mBq/dm(3)) and Ozalp (206 mBq/dm(3)). Even if within the normal range, a relation between the higher rate of the incidence of stomach and esophagus cancers with that of the higher rate of beta radionuclide activity was clear. On Spearman correlation analysis, the relation between higher beta radionuclide levels and cancer incidence was found to be statistically significant (p<0.01). According to the results of the analysis, Van residents receive an average 1.86 mSv/y annual dose from outdoor gamma radiation, ingestion of radionuclides in the drinking water, and indoor Rn-222 activity. Moreover, gross alpha and beta activities were found to be extremely high in all of the lakes around the city of Van, Turkey. Further investigations with long-term detailed environmental radiation measurements are needed regarding the relationship between cancer cases and environmental radioactivity in the city of Van.
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    Assessment of dose rates around Manisa (Turkey)
    (PERGAMON-ELSEVIER SCIENCE LTD) Erees, FS; Aközcan, S; Parlak, Y; Çam, S
    Natural radionuclide activity concentration of surface soils at 64 locations in central Manisa were measured using gamma spectrometry (ORTEC). The natural gamma radioactivity of the terrestrial radionuclides in soil samples and the gamma-absorbed dose rates of these radionuclides in air were calculated. In this study, track etch film (CR-39) was used to determine the distribution of radon levels in dwellings. The average annual effective dose equivalents from the calculated outdoor terrestrial gamma radiation for a person in Manisa is 66 mu Sv, whilst the annual effective dose equivalent from Rn-222 is calculated to be 4.83 mSv/yr. (c) 2006 Elsevier Ltd. All rights reserved.