Radioactivity Level Index Research Articles

Evaluation of natural radioactivity in rocks of Nilgiri hills and their radiation hazard to mankind

Twenty three rock samples were collected from various altitudes of Nilgiri hills, Tamil Nadu, India. A survey was carried out to determine the activity concentration of selected radionuclides ( 238 U, 232 Th, 40 K) by means of gamma-ray spectroscopy using NaI (Tl) detector. From the measured spectra, the mean activity of 238 U, 232 Th, 40 K are 7.13 Bq kg -1 , 30.47 Bq kg -1 and 346.06 Bq kg -1 , respectively. To evaluate the radiological effects, the absorbed dose rate, effective absorbed dose rate, radium equivalent activity, external and internal hazard indices, and radioactivity level index are also calculated. The mean absorbed dose rate of gamma radiation ranged from 11.90 nGy h -1 to 108.22 nGy h -1 . The activity concentration of 238 U, 232 Th, 40 K and the various radiological effects are below the internationally recommended maximum values.

Natural Radioactivity Assessment and Radiological Hazards in Soils from Qarun Lake and Wadi El Rayan in Faiyum, Egypt

The activity concentrations of naturally occurring 238U, 232Th and 40K in surface soils along Qarun Lake and Wadi El Rayan located in Faiyum, Egypt were determined. The measurements were carried out through gamma-ray spectrometry using a coaxial HPGe detector. The results were compared with those reported in the literature. The radiological hazard radium-equivalent activity index, external and internal indices, radioactivity level index, absorbed dose rate, annual effective dose rate and total absorbed dose rate associated with radioactivity in all samples were evaluated and compared with recommended values. Correlation studies between pairs of radionuclides were performed and discussed.

Natural radioactivity and dose rates for soil samples around Tiruchirapalli, South India using γ-ray spectrometry

The activity concentrations and the gamma-absorbed dose rates of the naturally occurring radionuclides 226 Ra, 232 Th, and 40 K were determined for 40 soil samples collected from Tiruchirapalli, South India, using g-ray spectrometry. The average activity concentrations of 226 Ra, 232 Th, and 40 K in the soil samples were found to be 29.9, 39.0, and 369.7 Bq kg−1 , respectively. The measured activity concentrations of both 226 Ra and 40 K in the soil were lower than the world average, whereas, the activity of 232 Th was higher than the world average. The concentrations of these radionuclides were also compared with the average activity of the Indian soil. The radiological hazard index was calculated and compared with the internationally approved values. The average external absorbed gamma dose rate was observed to be 79.9 nGy h−1 , with a corresponding average annual effective dose of 97.9 mSv y−1 , which was above the world average values. The values of Ra eq and H ex were found to be within the criterion limit, whereas, the radioactivity level index ( Ig) and total gamma dose rate were above the worldwide average values.

Natural Radioactivity Levels and Estimation of Radiation Exposure in Environmental Soil Samples from Tulkarem Province-Palestine

The activity concentrations of the natural radionuclides namely 238U, 232Th, 40K and 137Cs are measured for soil samples collected from different locations of Tulkarem district in West Back-Palestine. High-resolution gamma spectrometry (HPGe detector) was used to determine the activity concentration of these radionuclides in 72 surface soil samples taken from areas in and surrounding Tulkarem city. The concentration of 238U varied in the range 9.7 - 83.5 Bq kg–1 with an average value of 34.5 Bq kg–1, 232Th in the range 5.3 - 44.8 Bq kg–1 with an average value of 23.8 Bq kg–1, 40K in the range 10.2 - 404.0 Bq kg–1 with an average value of 120.0 Bq kg–1 and 137Cs in the range 1.0 - 24.5 Bq kg–1 with an average value of 7.8 Bq kg–1. The results have been compared with those of different countries of the world and Palestine. To assess the radiological hazard of the natural radioactivity, the absorbed dose rate (Dr), the radium equivalent activity (Raeq), the effective dose rate (Eeff), the annual effective dose equivalent (AEDE), Excess Lifetime Cancer Risk (ELCR), the radioactivity level index (Iγ), and the external (Hex) and internal (Hin) hazard indices were calculated .It can be concluded that no risk may threat the residents around and center of Tulkarem city except some areas which activity due to fallout 137Cs were high concentration levels. Hence the probability of occurrence of any of the health effects of radiation is low. Hence, measurements have been taken as representing baseline values of these radionuclides in the soil in studying area.

Investigation of the environmental impacts of naturally occurring radionuclides in theprocessing of sulfide ores for gold using gamma spectrometry

The possible environmental impacts of naturally occurring radionuclides on workersand a critical community, as a result of milling and processing sulfide ores forgold by a mining company at Bogoso in the western region of Ghana, have beeninvestigated using gamma spectroscopy. Indicative doses for the workers duringsulfide ore processing were calculated from the activity concentrations measured atboth physical and chemical processing stages. The dose rate, annual effectivedose equivalent, radium equivalent activity, external and internal hazard indices,and radioactivity level index for tailings, for the de-silted sediments of run-offfrom the vicinity of the tailings dam through the critical community, and forthe soils of the critical community’s basic schools were calculated and found tobe lower than their respective permissible limits. The environmental impact ofthe radionuclides is therefore expected to be low in this mining environment.

Natural radioactivity and associated dose rates in soil samples from Kalpakkam, South India

The activity concentration of naturally occurring radioactive elements such as 226Ra, 232Th and 40K were measured for 46 soil samples collected in the vicinity of the Madras atomic power station, Kalpakkam, South India using gamma-ray spectroscopy. The average activity concentration of 226Ra, 232Th and 40K in soil samples were found to be 22.6 ± 12.6, 92.8 ± 44.3 and 434.1 ± 131.1 Bq kg(-1), respectively. The activity concentration of natural radionuclides is higher than the world average except for (226)Ra. The external absorbed gamma dose rates due to 226Ra, 232Th and 40K are observed to be 74.6 ± 30.8 nGy h(-1) with a corresponding annual effective dose of 91.5 ± 37.8 µSv y(-1), which are also above the world average. The values of radium equivalent activity and external hazard index are less than the world average. Whereas, the values of the radioactivity level index (I(γ)) and the total gamma dose rate were found to be above the required criterion.

Radioactivity concentration in soil samples in the southern part of the West Bank, Palestine

The activity concentrations of naturally occurring radioactive materials such as (238)U, (232)Th and (40)K were measured for 38 soil samples collected from diverse zones in the southern area of West Bank, Palestine using gamma-ray spectroscopy. The measured activities of (238)U, (232)Th and (40)K were found to range from 32.9 to 104.7, 14.5 to 76.6 and 297 to 962 Bq kg(-1) with averages value of 68.7, 48.0 and 630 Bq kg(-1), respectively. The obtained values of activity concentrations are higher than the world average of 35, 30 and 500 Bq kg(-1) for (238)U, (232)Th and (40)K, respectively. The measured (137)Cs activity concentration was found to range from 1.8 to 36.1 Bq kg(-1) with an average value of 8.5 Bq kg(-1). The detected activities were attributed to the fallout of (137)Cs, which is the only man-made radionuclide. The calculated average of the total gamma-radiation dose rate of natural radionuclides, (137)Cs and cosmic radiation is 121.4 nGy h(-1). The radium equivalent activity (R(aeq)), dose rate (D(r)), external hazard index (H(ex)) and radioactivity level index (I(gamma)) in all samples are presented. Some values were found to be in the range of worldwide values, whereas others were above the worldwide values.

Distribution and environmental impacts of some radionuclides in sedimentary rocks at Wadi Naseib area, southwest Sinai, Egypt

The present study examines the natural radioactivity in some sedimentary rocks and their associated environmental impacts at Wadi Naseib area. Exposure rate (ER), dose rate (DR), radium equivalent activity (Ra eq), external hazard index ( H ex), internal hazard index ( H in) and radioactivity level index ( I γ) were calculated. Wadi Naseib area is covered with sedimentary rocks of early to late Paleozoic age. These rocks are classified into two types: mineralized and non-mineralized sediments. The radiometric investigations revealed that uranium and thorium contents reached up to 710 and 520 ppm, respectively, in the mineralized rocks. This was attributed to the presence of some secondary uranium minerals. All sediments had low values of eTh and K content. The exposure and dose rates exceeded public permissible values in the mineralized sediments. Exposure and dose rates were within the safety range for workers and the public in the non-mineralized sediments. The expected environmental impacts may be low due to the limited occurrence of U-mineralization and corresponding areas for radiation exposure. Some precautions and recommendations were suggested to avoid any possible environmental impacts from areas and/or raw materials of high intensity of natural radiation sources.