The radiological hazards associated with naturally occurring radioactive materials in soil samples from different geological locations have been studied using gamma spectrometry. The average activity concentration of ²²⁶ Ra, ²³² Th, and ⁴⁰ K were (16.4-74.6 Bq/kg), (12.0-44.7 Bq/kg), and (215.4-498.6 Bq/kg). The highest values of ²²⁶ Ra and ²³² Th occurred in Dodowa and Oyibi respectively. The ⁴⁰ K recorded the highest activity concentration of 498.6 Bq/kg, measured in soil from McCarthy Hills. The radium equivalent activity (Ra _eq ; 46.9-135.7 Bq/kg), the internal hazards index (H _in ; 0.29-0.52) the external hazard index (H _ex ; 0.22-0.37), the absorbed dose rate in air (23.3-75.8 nGy/h), and the annual effective dose (E _T ) (44.4-79.4 uSv/y) were evaluated to assess the radiation hazard to the populace living in dwellings made of these soil as a building material. The results obtained were found to be within the acceptable limits for public exposure control recommended by the European Commission, International Commission on Radiological Protection, and Organization for Economic Cooperation and Development-Nuclear Energy Agency.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Context: The soil is a complex mixture of different compounds and rocks. In the natural environment, it is an important source of exposure to radiation due to naturally occurring, gamma emitting radionuclides which include ²²⁶ Ra, ²³² Th and ⁴⁰ K present in the soil. Aims: The study of distribution of these radionuclides in soil and rock is of great importance for radiation protection and measurements. Materials and Methods: The activity concentrations of ²²⁶ Ra, ²³² Th, and ⁴⁰ K in soil and rock samples collected in Mandya District, Karnataka state, India have been measured by gamma ray spectrometry. Results: The average activity concentrations of ²²⁶ Ra, ²³² Th, and ⁴⁰ K (Bq/kg) are found to be 40.2, 62.3, and 317.5 Bq/kg, respectively, in soil samples and 30.5, 34.4, and 700.2 Bq/kg, respectively, in rock samples. Conclusion: The concentrations of radionuclides in soil samples are found to higher than in rock samples. The concentrations of radionuclides in soil and rock samples in the study area are slightly higher than Indian average and world average values

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

The distribution of natural radioactivity in beach sand samples collected from naturally high background radiation areas of south west coast of Tamil Nadu in India is studied by gamma spectrometry. The activity concentration of radionuclide collected from the study area ranges from 18.9 ± 4.6 Bq/kg to 260.5 ± 29.4 Bq/kg for ²²⁶ Ra, 534.5 ± 34.0 Bq/kg to 2961.4 ± 33.7 Bq/kg for ²³² Th, and 40.6 ± 7.2 Bq/kg to 148.7 ± 17.9 Bq/kg for ⁴⁰ K. The measured activity of ²²⁶ Ra and ²³² Th in soil samples collected from the study area is higher than the activity of ⁴⁰ K. The external hazard index, internal hazard index, absorbed dose rate, and annual effective dose equivalent are calculated and tabulated. It is found that all the evaluated values are higher than the safe limit. The annual effective dose of radiation ranges from 0.41 mSv to 2.35 mSv due to naturally occurring radionuclide.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

[FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

[FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Context: Natural radionuclides are wide spread in air, water, soil, plants and in consequence in the human diet. ²²² Ra is the daughter product of ²²⁶ Ra which belongs to ²³⁸ U radioactive series. Aims: Radon enters the human body through ingestion of water and inhalation. Since alpha emitters are the most dangerous, studies on water containing dissolved radon are very important. Materials and Methods: The activity concentration of ²²² Ra has been analyzed in water samples collected from lakes, open wells, drilled wells, taps and rivers in and around Mysore city, Karnataka State, India using radon emanometric technique. Results: The present study shows a wide range of radon concentration in water, which varies from below detection limit to 643.9 BqL ^-1 with a median of 15.8 BqL ^-1. An annual effective dose with a median of 0.043 μSv y^-1 was estimated from the ingestion of ²²² Ra through water. Conclusions: ²²² Rn concentration in 80% of bore-well water samples are higher than the maximum acceptable contaminant level of 11.1 BqL ^-1 as prescribed by the environmental protection agency.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

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 ( I_g) and total gamma dose rate were above the worldwide average values.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Neutron activation analysis (NAA) is a well-established analytical technique. It has many advantages as compared to the other commonly used techniques. NAA can be performed in a variety of ways depending on the element, its activity level in the sample, interference from the sample matrix and other elements, etc., This technique is used to get high analytical sensitivity and low detection limits (ppm to ppb). The high sensitivity is due to the irradiation at high neutron flux available from the research reactors and the activity measurement is done using high resolution HPGe detectors. In this paper, the activity estimation of soil samples using neutron activation and direct gamma spectrometry methods are compared. Even though the weights of samples considered and samples preparation methods are different for these two methods, the estimated activity values are comparable.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Radiation sources are used in various industrial applications like industrial radiography, industrial irradiation, industrial fluoroscopy, nucleonic gauges, well logging etc.. Gamma, beta X-ray as well as neutron sources are used for various applications. Number of radiation workers in this field has increased over the years. Due to operating conditions prevailing during the exposure as well as the strength of the sources used in some of the applications, radiation protection plays an important role in this field. Analysis of doses received by radiation workers in industry provides information on trends of doses as well as adequateness of radiation protection practices followed in this sector. In India, National Occupational Dose Registry System (NODRS) of Radiological Physics and Advisory Division (RPAD), Bhabha Atomic Research Centre (BARC) maintains personnel dose information of monitored radiation workers in the country. Analysis of occupational dose data of industrial radiation workers for last 10 years, i.e., 1999-2008 has been presented in this paper. It is observed that even though there is an increase in monitored radiation workers, percentage of persons receiving radiation exposure has come down during this period. There is also a decrease in the average annual dose as well as the collective dose. Further analysis of sub-categories shows that industrial radiography operations are the main contributor for collective dose (about 77%) followed by well logging and industrial X-ray operations (about 8% each). Thus, in addition to industrial radiography, attention is also to be given to operations in these areas.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Background and Aim: Gamma radiation is commercially used in food preservation by extending shelf life and the success of radiation preservation of food depends upon the ability of the processor of successful measurement of the radiation dose delivered to the foods. Several dosimeters are already used in radiation processing plant to measure the delivered dose. The aim of the present study was to develop a simple and appropriate chemical dosimetry system covering a wide dose range (1-30kGy) of food irradiation. Materials and Methods: The response of the ferrous ammonium sulfate (Fe(NH ₄ ) ₂ (SO ₄ ) ₂ ,6H ₂ O) - cupric sulfate (CuSO ₄ ,5H ₂ O) dosimetry system was studied at two different gamma chambers of GC-5000 and GC-900 and at a radiation processing plant with four different salt concentrations and at the dose range of 1-30kGy. Results and Discussion: The system with highest salt concentration i.e. with 6x0.001mmol Fe(NH ₄ ) ₂ (SO ₄ ) ₂ ,6H ₂ O + 6x0.01mmol CuSO ₄ ,5H ₂ O showed linear response in the applied dose range of 1kGy to 30kGy. Good reproducibility of the system was observed at both GC-5000 and GC-900 with different dose rate and irradiation temperature. Routine dosimetry and dose mapping at radiation processing plant with the standard Ceric-cerous dosimetry system with same salt concentration also showed good agreement with ΁5% difference. The system was stable upto 7 days before and after irradiation at 4 ^o C and at darkness. The estimated overall precision for the dose assessment over the dose range of interest was about ΁2% irrespective of the dose rate and irradiation temperature. Conclusion: The ferrous ammonium sulfate (Fe(NH ₄ ) ₂ (SO ₄ ) ₂ ,6H ₂ O) - cupric sulfate (CuSO ₄ ,5H ₂ O) dosimetry system with highest salt concentration i.e. with 6x0.001mmol Fe(NH ₄ ) ₂ (SO ₄ ) ₂ ,6H ₂ O + 6x0.01mmol CuSO ₄ ,5H ₂ O can be successfully used as chemical dosimeters in the dose range of 1-30kGy.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Protective wear (like boiler suits, hand gloves etc.) is necessary while handling radioactive material in plants/laboratories. During the course of work, it is quite possible that protective wear may get contaminated. These protective wear are packed in laundry bags and send to Decontamination Centre (DC) for washing. There is a need for monitoring the laundry bags at the time of receipt, as well as before dispatch to respective locations to comply with AERB guidelines. To avoid cross contamination during wash cycle, contaminated bags (>0.5 mR/h on surface) need to be segregated. Present paper describes the development of such system for monitoring surface dose rate on bags at the time of receipt.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]