Browsing by Author "Garavaglia, M."
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Item Assessment of natural radioactivity and radon exhalation rate associated with rock properties used for construction in greater Accra region, Ghana(Springer, 2021) Otoo, F.; Darko, E.O.; Garavaglia, M.; Adukpo, O.K.; Amoako, J.K.; Tandoh, J.B.; Inkoom, S.; Nunoo, S.; Adu, S.Natural radioactivity, radon exhalation and rock properties have been studied using gamma spectrometry, CR-39 detectors and weighing methods. Statistical tool was used to study the relationship between the activity concentration and properties associated with the rocks. The purpose is to determine the rocks with good properties and lower radioactivity levels in order to reduce radiological efect when used as building materials. Gneiss recorded good properties while quartzite was found to contain poor and lower value of radiological parameters as compared to granite and sandstone. Radon-222 was found to correlate well with the properties than radionuclides of radium-226, thorium-232 and potassium-40.Item Public exposure to natural radioactivity and radon exhalation rate in construction materials used within Greater Accra Region of Ghana(Scientific African, 2018-12) Otoo, F.; Darko, E.O.; Garavaglia, M.; Giovani, C.; Pividore, S.; Andam, A.B.; Amoako, J.K.; Adukpo, O.K.; Inkoom, S.; Adu, S.The natural radioactivity of 238U, 232Th, 40K, radiological hazards and 222Rn exhalation rate in building materials used within Greater Accra Region of Ghana, have been measured using Gamma spectrometry and CR-39. The results obtained are as follows 238U (2.6–47.1 Bq/kg), 232Th (3.6–43.0 Bq/kg), 40K (62.8–1222.2 Bq/kg), radium equivalent (32.7–174.3 Bq/kg), internal hazard index (0.04–0.51), external hazard index (0.04–0.23), activity concentration index (0.10–0.63 mSv/y) absorbed dose rate (9.5–76.3 nGy/h), outdoor effective doses (11.6–93.6 μSv/y), indoor effective doses (46.5–374.1 μSv/y,) and excess lifetime cancer risk (0.04 × 10−3–0.33 × 10−3). 222Rn exhalation rate (3.1 × 10−5–11.4 × 10−5 Bq/m2 h), 222Rn activity (17.4–42.6 Bq/m3), effective radium (0.19–0.64 Bq/kg). Positive correlation was found between 238U and 222Rn. The results were discussed in terms of limits to the accepted natural radioactivity levels and compared with similar studies reported in other countries. The gneiss rocks recorded excess lifetime cancer risk values of (0.32 × 10−3 and 0.33 × 10−3) greater than the world value of 0.29 × 10−3 proposed by UNSCEAR, 2000. With exception gneiss rocks from Shai hills which recorded high value of cancer risk as compare to the world average value, all the studied building materials do not pose any radiological effects to the people of Greater Accra Region when used for construction.Item Seasonal indoor radon studies in buildings of Accra Metropolis of Greater Accra region of Ghana(Radioprotection, 2018-06) Otoo, F.; Darko, E.O.; Garavaglia, M.; Giovani, C.; Pividore, S.; Andam, A.B.; Amoako, J.K.; Adukpo, O.K.; Tandoh, J.B.; Inkoom, S.Indoor radon concentration for annual, rainy and dry season have been studied in 228 buildings which includes bedroom, kitchen, sitting room, laboratories and offices in Accra metropolis of Greater Accra of Ghana. The passive radon CR-39 SSNTD was used for this study. The cumulative frequency distribution, normalizing Q-Q plots, Kolmogorov-Smirnov and Shapiro-Wilk statistical test showed that the result of both workplaces and dwellings are not normally distributed. The strong positive correlation between the two seasons occurred at 95% confidence level with 2 tailed. The rainy season recorded highest coefficient variation of r2 = 0.982. Statistical analysis of median (39.3), AM (103.4), GM (57.9) and GSD (3.2) for rainy season were greater than that of the dry season of median (26.9), AM (88.2), GM (49.2) and GSD (2.8) respectively. Rainy season was found to contain high radon concentrations than the dry season for all the studied locations. In general, workplace had radon concentration far greater than dwellings. The results obtained from this study ranged between 13.6 to 533.7 Bq/m3, out of which 9.6%, 12.7% and 3.5% were found to be greater than action levels proposed by WHO, EC and ICRP.