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ORIGINAL ARTICLES
Effect of gamma irradiation on germination, growth, and biochemical parameters of
Terminalia arjuna
Roxb
Akshatha , KR Chandrashekar, HM Somashekarappa, J Souframanien
January-March 2013, 36(1):38-44
DOI
:10.4103/0972-0464.121826
The impact of gamma irradiation on
Terminalia arjuna
(
T. arjuna
), one of the potent medicinal plants for cardiac disease is described in this article. The seeds of
T. arjuna
were irradiated with different doses of gamma radiation ranging from 0 to 200 Gy using the
60
Co source. The effect of gamma radiation on the growth and biochemical constituents were compared with the control plants. Germination speed at 25 Gy was found to be 0.65, which was double compared to the un-irradiated seeds. An increase in germination percentage, vigor index, and relative growth rate, in terms of dry weight was noticed at lower doses of the radiation treatment. The proline content increased with increasing doses. The chlorophyll content was found to have increased to 12.2 mg/g FW at 100 Gy compared to the control level of 8.44 mg/g FW. Increased phenolic content and radical scavenging capacity was observed at 25 and 150 Gy. Hence, lower doses of radiation treatment may be used to increase the germination, growth, and vigor, and also the enhancement of plant metabolites like proline and phenolics in
T. arjuna
.
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33
11,471
1,478
Antioxidant, antibacterial, and ultraviolet-protective properties of carotenoids isolated from
Micrococcus
spp.
Devihalli Chikkaiah Mohana, Sreerangegowda Thippeswamy, Rayasandra Umesh Abhishek
October-December 2013, 36(4):168-174
DOI
:10.4103/0972-0464.142394
Carotenoids are the most common naturally occurring bioactive terpenoid pigments, which are commonly produced by a wide variety of plants and microbes. The present study was aimed to evaluate the antioxidant, antimicrobial and radio-protective properties of carotenoid pigments isolated from ultraviolet (UV)-C resistant
Micrococcus
spp. The UV-C resistant
Micrococcus roseus
and
Micrococcus luteus
were isolated from the soil samples of Savandurga hills region, Karnataka (India), and their pigments were identified as carotenoids based on spectral analysis. The UV-protective efficacies were determined by cling-film assay. Further, the antioxidant activities of pigments were evaluated by 2,2-diphenyl-1-picrylhydrazyl assay, and antibacterial activities by disc diffusion and broth microdilution assays. The optimum growth and pigment production by
M. roseus
and
M. luteus
were observed at temperature ranged between 35°C and 37°C, pH 7.0-8.0, NaCl 5.0-7.0%, and sucrose as major carbon and KNO
3
as major nitrogen sources. In the present investigation, the isolated carotenoid pigments of
M. roseus
and
M
.
luteus
showed significant UV protective activity along with antioxidant (IC
50
3.5-4.5 mg/mL) and antibacterial (minimal inhibitory concentration 0.25-2.0 mg/mL) properties.
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24
12,316
1,325
Radiation shielding of polymer composite materials with wolfram carbide and boron carbide
Alparslan Erol, Isa Pocan, Emre Yanbay, Onur Alp Ersoz, Fatma Yurt Lambrecht
January-March 2016, 39(1):3-6
DOI
:10.4103/0972-0464.185147
In general, lead is used as shielding material for protection against radiation. In spite of its high density, lead is toxic and lead aprons are very heavy for personal shielding. Thus, there is a need for nontoxic, light, and environmental friendly radiation-shielding materials. Polymers cannot be effective against gamma radiation on their own. High-density metal wolfram carbide could be useful against gamma radiation, and boron carbide could also be useful for neutron shielding. In this study, high-density polyethylene, boron carbide, and wolfram carbide can be mixed in certain amounts and composite discs can be obtained in this way. According to results, a new shielding material is efficient for gamma radiation.
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23
9,042
1,191
A study of radon concentration in drinking water samples of Amritsar city of Punjab (India)
Ajay Kumar, Manpreet Kaur, Sumit Sharma, Rohit Mehra
January-March 2016, 39(1):13-19
DOI
:10.4103/0972-0464.185155
Radon concentration has been estimated in drinking water samples of 17 selected locations in Amritsar city of Punjab, India. RAD7, an electronic solid state radon monitor has been used to evaluate the radon concentration in collected drinking water samples. The corresponding annual mean effective dose for ingestion and inhalation was calculated according to parameters introduced by UNSCEAR (2000) report. The radon concentration in drinking water samples has been found to vary from 0.53 ± 0.11 to 11.20 ± 1.40 Bql
−1
. The values of radon concentration in these samples were found below the recommended limit proposed by USEPA (1991) and European Commission (2001). The range of calculated annual effective dose varied between 1.45 and 30.57 ΅Svy
−1
. These values lie well within the safe limit prescribed by the WHO (2003) and European council (2005). The purpose of this study was to assess the radiological risk, if any, to human health due to consumption of drinking water that is available at Amritsar city.
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20
4,853
516
Laser flourimetric analysis of uranium in water from Vishakhapatnam and estimation of health risk
RC Bhangare, M Tiwari, PY Ajmal, SK Sahu, GG Pandit
July-September 2013, 36(3):128-132
DOI
:10.4103/0972-0464.137478
Uranium is a naturally occurring radioactive element that is both radiologically and chemically toxic. The presence of uranium in the aquatic environment is due to the leaching from natural deposits, release in mill tailings, the combustion of coal and other fuels, and the use of phosphate fertilizers that contain uranium. Intake of uranium through air and water is normally low, but in circumstances in which uranium is present in a drinking water source, the majority of intake can be through drinking water route. The uranium concentrations in ground water samples from Vishakhapatnam, India were estimated using laser fluorimetric technique and were observed to range from 0.6 to 12.3 ppb. The laser fluorimetry technique was found to be an excellent tool for direct measurement of uranium concentration in water samples at ultra-trace levels. The annual effective dose, cumulative dose for 70 years and the lifetime excess cancer risk from drinking of this water were calculated. The risks were low averaging only 10.6 × 10
-6
as none of the samples were observed to exceed the WHO recommended uranium concentration limit of 30 ppb.
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16
5,979
745
Measurement of terrestrial gamma radiation dose and evaluation of annual effective dose in Shimoga District of Karnataka State, India
DR Rangaswamy, E Srinivasa, MC Srilatha, Jadiyappa Sannappa
October-December 2015, 38(4):154-159
DOI
:10.4103/0972-0464.176152
Human beings are continuously exposed to the radiations coming from terrestrial and extraterrestrial sources and inside their own bodies. This study presents the results of indoor and outdoor ambient gamma dose rates in and around granite regions of Shimoga District, and these measurements were carried out by using environmental radiation Dosimeter ER-709 which is a portable detector. By the measured average absorbed dose rates, annual effective dose (AED) has been calculated by a standard method. Results showed that the indoor and outdoor absorbed dose rates in air of Shimoga district ranged between 114.05 ± 2.11 to 332.6 ± 3.99 nGy/h and 87 ± 1.7 to 276.66 ± 4.76 nGy/h. The indoor and outdoor AED ranged between 0.559 to 1.631 mSv/year with an average value of 0.872 mSv/year and 0.106 to 0.339 mSv/year with an average value of 0.235 mSv/year, respectively. The calculated indoor and outdoor AEDs were found to be higher than the world average.
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16
3,720
477
Influence of physico-chemical parameters on the distribution of uranium in the ground water of Bangalore, India
Ningaiah Nagaiah, Gladys Mathews, Karthik Kumar Mysore Balakrishna, Ambika Madalakote Rajanna, Karunakara Naregundi
October-December 2013, 36(4):175-180
DOI
:10.4103/0972-0464.142389
Laser-Induced Fluorimetry has been used to measure the concentration of uranium in the ground water samples collected from the selected study locations of Bangalore city, India. The concentration of uranium in the collected water samples is found to be in the range 0.24 μg/l to 770.1 μg/l, with a geometric mean (GM) value of 18.9 μg/l. About 35% of the water samples show the concentration of uranium above the safe limit of 30 μg/l, set by the United States Environmental Protection Agency (USEPA). The annual effective dose associated with the ingestion of uranium by the adult population of the region has been estimated using the International Commission on Radiation Protection (ICRP) and World Health Organization (WHO) guidelines. Few physicochemical parameters of water such as pH, Total dissolved solids (TDS), major cations, major anions, and trace elements were also measured. The correlation coefficient among the measured parameters was determined to find the dependence, if any, on the concentration of uranium in the water samples.
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15
3,422
338
Distribution of natural uranium in groundwater around Kudankulam
BS Selvi, B Vijayakumar, BK Rana, PM Ravi
January-March 2016, 39(1):25-29
DOI
:10.4103/0972-0464.185164
A systematic study was carried out to estimate the uranium concentration in the ground water around Kudankulam in Southern Tamil Nadu. The uranium concentration in ground water varies from 0.2 to 6.6 μg/l, with a mean value of 2.0 μg/l. The Quantalase uranium analyzer was used to measure the uranium concentration. These groundwater samples were analyzed for the water quality parameters such as pH, conductance, total dissolved solids (TDS), salinity, chloride, and sulfate. An attempt has been made to correlate the uranium concentration with the water quality parameters. It is observed that conductance, TDS, salinity, chloride, and sulfate show positive correlation with uranium concentration.
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15
3,033
350
Estimation of indoor and outdoor effective doses and lifetime cancer risk from gamma dose rates along the coastal regions of Kollam district, Kerala
S Monica, AK Visnu Prasad, SR Soniya, PJ Jojo
January-March 2016, 39(1):38-43
DOI
:10.4103/0972-0464.185180
The exposure of human beings to ionizing radiation from natural sources is a continuously inescapable feature of life on earth. Direct measurement of absorbed dose rates in air has been carried out in many countries of the world during the last few decades. Such investigations are useful for the assessment of public dose rates. Indoor and outdoor gamma dose rates were evaluated along the coastal regions of Kollam district, Kerala, through direct measurement using portable gamma dosimeter, and analysis of soil sample for activity of
238
U,
232
Th, and
40
K concentration was carried out using gamma spectroscopy. Indoor and outdoor exposure rates, the annual effective dose (AED), and lifetime cancer risk of residents along the coastal regions of Kollam district, Kerala, were evaluated. The reduction coefficients were also calculated for the region. The mean indoor effective dose due to background gamma along the coastal region of Neendakara panchayath was found to be 7.56 mSvy
−1
which is larger as compared with the worldwide average of the AED of 0.48 mSv y
−1
and the outdoor mean effective dose of 4.83 mSvy
−1
. Estimated excess lifetime cancer risk (ELCR) from indoor AED equivalent ranges from 22.56 to 26.46 × 10
−3
and ELCR from outdoor ranges from 14.95 to 16.65 × 10
−3
. Excess average lifetime cancer risk estimate from all the values is found to be 20.56 × 10
−3
, which is larger compared with the resulting worldwide average 0.25 × 10
−3
.
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15
5,036
596
Analysis of radon concentration in drinking water in Hanumangarh district of Rajasthan, India
Vikas Duggal, Rohit Mehra, Asha Rani
April-June 2013, 36(2):65-70
DOI
:10.4103/0972-0464.128870
Radon levels were measured in drinking water samples collected from Hanumangarh district of Rajasthan, India. The measurements were performed by RAD7 an electronic radon detector manufactured by Durridge Company Inc. The radon concentration in these samples is found to vary from (1.6 ± 0.6) to (5.4 ± 0.7) Bq/l with a mean value of (3.3 ± 1.1) Bq/l. These recorded values are compared with the safe limit values recommended for drinking water by various health and environmental protection agencies. The recorded values of radon concentration are within the safe limit of 11 Bq/l recommended by the US Environmental Protection Agency. The annual effective dose for ingestion and inhalation is also evaluated in this research. The estimated total effective dose varies from 4.29 to 14.47 μSv/year. The total effective dose in all locations of the studied area is found to be within the safe limit (0.1 mSv/year) recommended by World Health Organization and European Council.
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10
4,057
475
Assessment of natural radioactivity and associated radiation indices in soil samples from the high background radiation area, Kanyakumari district, Tamil Nadu, India
AK Ajithra, B Venkatraman, MT Jose, S Chandrasekar, G Shanthi
January-March 2017, 40(1):27-33
DOI
:10.4103/rpe.RPE_31_16
Assessment of natural radioactivity is very important from different points of view, especially for assessment of radiation exposure to human. In the present study, natural radionuclide concentrations of
238
U,
232
Th, and
40
K were measured by gamma spectrometry using HPGe detector in soil samples collected from Southwest coast of Kanyakumari district, Tamil Nadu. The radiological index parameters due to natural radionuclides such as radium equivalent activity, absorbed dose rate, annual effective dose rate, external hazard index, internal hazard index, and gamma index were calculated for the soil samples. All the calculated radiological index values are higher than world average values and the recommended safety limits. Multivariate statistical techniques such as Pearson correlation, principal component analysis, and cluster analysis were applied to know the relation between radionuclides and radiological parameters and to study the spatial distribution of radionuclides.
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10
4,143
401
Naturally occurring radionuclide transfer from soil to vegetables in some farmlands in Ghana and statistical analysis
Theophilus Adjirackor, Emmanuel Ofori Darko, Frederic Sam
January-March 2017, 40(1):34-43
DOI
:10.4103/rpe.RPE_11_17
Distribution studies of natural radionuclides in soil, statistical analysis of activity concentrations, and transfer factors (TFs) from soil to the vegetables grown in some selected farming communities within the Greater Accra Region in Ghana were carried out. The measurements were carried out through a gamma-ray spectrometry. The mean activity concentrations of
226
Ra,
228
Ra, and
40
K in the fertilized soils were 20.0 ± 3.9 Bq/kg, 39.0 ± 7.0 Bq/kg, and 143.6 ± 23.3 Bq/kg, respectively. For the nonfertilized soils, mean activity concentrations were found to be 12.07 ± 2.55 Bq/kg for
226
Ra, 27.1 ± 6.3 Bq/kg for
228
Ra, and 87.8 ± 18.5 Bq/kg for
40
K. These results were compared with reported ranges in the literature from other location in the world. The TF for
226
Ra,
228
Ra, and
40
K from fertilized soil to vegetables was evaluated.
226
Ra TF values from fertilized soil to vegetables were found to be higher in lettuce in Farm 6. The highest TF for
40
K and
228
Ra was found in cauliflower in Farm 4.
40
K TF was higher than those values reported in other studies. The activity concentration in fertilized and unfertilized soil exhibited slightly positively skewed, negatively skewed, leptokurtic, and platykurtic distribution in terms of skewness and kurtosis. The activity concentration of natural radionuclides in fertilized and unfertilized soil is statistically insignificant at 5% level of significance using independent
t
-test. Pearson's correlation coefficient exhibited a negative correlation between
226
Ra and
228
Ra in fertilized soil and
226
Ra and
228
Ra in vegetables but was statistically insignificant while
40
K in fertilized soil exhibited a positive correlation with
40
K in vegetables and was statistically significant at 5% level of significance with a coefficient of determination of 1%, 61%, and 10% for
226
Ra,
40
K, and
228
Ra, respectively.
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10
3,377
428
Assessment of radon/thoron exhalation rate in the soil samples of Amritsar and Tarn Taran district of Punjab state
Manpreet Kaur, Ajay Kumar, Sandeep Kaur, Kawaljit Kaur
October-December 2018, 41(4):210-214
DOI
:10.4103/rpe.RPE_53_18
In the present study, the radon mass and thoron surface exhalation rates have been measured in the soil samples collected from the villages of the Amritsar and Tarn Taran districts of Punjab using the active portable device, i.e., SMART RnDuo monitor to quantify the level of rate of radon and thoron exhalation. The average values of radon mass exhalation rate were 20 ± 7 mBq kg
−1
h
−1
and 23 ± 5 mBq kg
−1
h
−1
in Amritsar and Tarn Taran districts, respectively. Similarly, the average value of thoron surface exhalation rate was 664 ± 237 Bq m
−2
h
−1
and 1531 ± 1503 Bq m
−2
h
−1
in Amritsar and Tarn Taran districts, respectively.
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10
2,077
191
ARTICLES
Determination of natural radioactivity in beach sand in the extreme south of Bahia, Brazil, using gamma spectrometry
Danilo C Vasconcelos, Claubia Pereira, Arno H Oliveira, Talita O Santos, Zildete Rocha, Maria Ângela de B. C. Menezes
July-September 2011, 34(3):178-184
DOI
:10.4103/0972-0464.101714
The natural radionuclides activity concentrations in beach sand of the extreme south of Bahia, Brazil, was measured by Gamma Spectrometry. The Radium Equivalent Activity, the external hazard index, the absorbed dose rate and the annual effective dose were assessed and compared with internationally published values for external dose and activity concentrations. The activity concentrations of
226
Ra,
232
Th and
40
K in beach sand ranged from 8.4 to 8,300 Bqkg
-1
with a mean value of 910 Bq.kg
-1
, from 21 to 18,450 Bqkg
-1
with a mean value of 2,220 Bqkg
-1
and from 3.4 to 3,110 Bqkg
-1
with a mean value of 352 Bqkg
-1
, respectively. The results indicate that the absorbed dose rates range from 21 to 14,450 nGyh
-1
with mean value of 1,792 nGy.h
-1
. The highest value of gamma dose rates among the studied beaches were found in Cumuruxatiba (14,450 nGyh
-1
). The annual effective dose range between 0.03 and 17.70 mSvy
-1
, with the mean value of 2.20 mSvy
-1
. In four studied beaches, the assessed outdoor annual effective doses are above the worldwide average of 0.07 mSvy
-1
as reported by the United Nations Scientific Committee on the Effects of Atomic Radiation. Especially in the area of black sands, a big part of Cumuruxatiba beach, whose annual effective dose of 17.70 mSvy
-1
is much higher than worldwide average.
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8
4,183
533
ORIGINAL ARTICLES
Para-
tert-
butylcalix[4]arene as promising complexing agent for removal of the strontium from the aqueous medium
Navneet Sharma, Sudha Rana, Hosakote Gurumallappa Shivkumar, Rakesh Kumar Sharma
April-June 2013, 36(2):78-84
DOI
:10.4103/0972-0464.128873
Strontium-90 is one of radioactive nuclear fallout products, can cause serious health effects. Efficient techniques are needed to remove radioactive strontium from contaminated persons. In this study complexation properties of the
p-tert
-butylcalix[4]arene has been evaluated against cold strontium nitrate. Ultra violet-visible (UV-vis) and fluorescence spectrophotometric techniques were used for the qualitative analytical screening and the inductively coupled plasma-atomic emission spectrometry (ICP-AES) technique used for the quantitative complexation of
p-tert
-butylcalix[4]arene with strontium nitrate. UV-vis, fluorescence spectroscopy and ICP-AES studies confirmed the complexation of
p-tert
-butylcalix[4]arene and strontium. Extraction study of strontium from picric acid by trans-chelation method proves that
p-tert
-butylcalix[4]arene is nearly 87% ± 3% effective. Complexation can be attributed to the cation-lone pair interaction and the bonding between the Sr
2+
and the hydroxyl group of the
p-tert
-butylcalix[4]arene implying its promise as a complexing agent for the removal of strontium.
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8
4,019
370
Assessment of natural radioactivity levels and identification of minerals in Brahmaputra (Jamuna) river sand and sediment, Bangladesh
Md. Ibrahim Khalil, Ratan Kumar Majumder, Md. Zafrul Kabir, Farah Deeba, Md. Nazrul Islam Khan, Md. Idris Ali, Debasish Paul, Md. Abu Haydar, Syed Mohammad Azharul Islam
October-December 2016, 39(4):204-211
DOI
:10.4103/0972-0464.199980
Distribution of the natural radionuclides (
238
U,
232
Th, and
40
K) and their specific activities in sands and sediments of the Brahmaputra (Jamuna) river of Bangladesh together with mineral characteristics has been studied to assess the radiation levels as well as to develop a baseline database for comparison in the future in case of any change in the area under study due to anthropogenic activities. The radiological parameters of natural radioactivity were assessed calculating the radium equivalent activity, hazard index, the absorbed dose rate, and annual effective dose. The average activity concentrations of
226
Ra (
238
U),
232
Th, and
40
K in sand and sediment were found to be 59 ± 2 & 60 ± 2 Bq/kg, 113 ± 5 & 135 ± 5 Bq/kg, and 983 ± 42 & 1002 ± 43 Bq/kg, respectively. The calculated average absorbed dose rate and annual effective dose were found to be 150 nGy/h and 0.18 mSv/year respectively. These high values are associated with mineral content of the sediment. X-ray diffraction peaks of sand and sediment samples identify quartz, feldspar, rutile, zircon, monazite, uranium fluoride, hematite, kyanite, and uranium arsenide minerals to be present in the samples.
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8
2,724
347
Measurement and validation of uranium isotope ratio in uranium ore for isotopic fingerprinting
Suchismita Mishra, Sarata Kumar Sahoo, Probal Chaudhury, KS Pradeepkumar
January-March 2017, 40(1):3-8
DOI
:10.4103/rpe.RPE_36_16
Accurate determination of uranium isotope ratio can act as an efficient fingerprint in the nuclear forensics to identify source and intended use of illicit trafficking of uranium material. In this context, a rapid chemical separation technique to isolate uranium from uranium ore sample was developed using commercial extraction chromatographic resin. Uranium isotope ratio was measured using thermal ionization mass spectrometry (TIMS). Standard reference material (NBS U010) was used for validating the accuracy and precision of isotope ratio measurement by TIMS. The method is successfully applied to a natural ore (uraninite ore) for the determination of naturally occurring uranium isotope ratio.
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8
3,051
406
Efficiency of high-purity germanium detector at characteristic gamma energies of
198
Au and
58
Co and covariance analysis
Imran Pasha, B Rudraswamy, E Radha, V Sathiamoorthy
July-September 2018, 41(3):110-114
DOI
:10.4103/rpe.RPE_38_18
Naturally occurring
197
Au and
58
Ni foils were subjected to the neutron irradiation by placing them in a dry tube-I of Kalpakkam Mini reactor to produce gamma emitting
198
Au and
58
Co nuclear reaction products. The efficiency study of high-purity germanium detector corresponding to characteristic gamma energies 0.4118 and 0.8107 MeV of
198
Au and
58
Co was carried out by the methods of calibration of
152
Eu and covariance.
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8
2,783
308
REVIEW ARTICLE
Review on studies in natural background radiation
Abdu Hamoud Al-Khawlany, AR Khan, JM Pathan
October-December 2018, 41(4):215-222
DOI
:10.4103/rpe.RPE_55_18
The environment around us is radioactive due to background radiation emitted from the sky, earth's crust, food, water, and building materials. The human body gets exposed to radiation doses of about 82%, which are out of control; they arise from background radiation sources such as terrestrial, cosmic, and exposure to internal radiation. The background dose from cosmic radiation depends on the altitude, and regions with high altitude have high radiation doses. Natural radioactivity is present in the earth and is present in the different environment geological formations in the rocks and soils. Gamma radiation emitted from naturally occurring radioisotopes, such as
40
K and the radionuclides from the
232
Th and
238
U series and their decay products which exist as trace levels in all ground formations, represents the main external source of irradiation to the human body. Their concentrations in rocks, soils, and sands depend on the local geology of each region in the world. Naturally occurring radioactive materials have terrestrial-origin radionuclides since the creation of the earth. The dose rate of background radiation increases because of the existence of some quarries and springs in some regions which are called high-level background radiation regions. The type of construction materials used in houses can be affecting the dose rate of background radiations. Study of radioactivity in the environment is important to monitor the levels of radiation to which human is exposed directly or indirectly. Recently, several international studies have been done and different values were measured. In this article, a review and literature survey of background radiations such as terrestrial, cosmic, and food radiation was carried out.
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8
3,501
462
ARTICLES
Radiation levels and radionuclide distributions in soils of the gogi region, a proposed uranium mining region in north Karnataka
I Yashodhara, N Karunakara, K Sudeep Kumar, Rudra Murthy, RM Tripathi
October-December 2011, 34(4):267-269
DOI
:10.4103/0972-0464.106196
This paper reports the results of systematic studies aimed at generating a baseline database on the radiation levels and radionuclide distribution in the Gogi region, which has been identified as a prospective uranium mining region. A total of 39 villages in a 0-30 km radius zone of the Gogi region were covered under this study. The ambient gamma absorbed dose rates were measured using portable gamma dosimeters. The activity concentrations of
226
Ra,
232
Th, and
40
K in the soil samples were measured by the HPGe gamma spectrometry method. The ambient gamma absorbed dose rate varied in the range of 126-428 nGy h
-1
, with a median value of 143 nGy h
-1
. The activities of
226
Ra,
232
Th, and
40
K in the soil varied in the range of 5-176 Bq kg
-1
, 9-687 Bq kg
-1
, and 81-1493 Bq kg
-1
, with the corresponding median values of 36 Bq kg
-1
, 85 Bq kg
-1
, and 859 Bq kg
-1
, respectively. The study showed a highly non-uniform distribution of primordial radionuclides in the soil, with activity concentrations varying significantly within a small area. The results observed in the present study were compared with the literature values reported for other parts of India and the worldwide average values, and discussed.
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7
2,400
366
Analysis of neutron streaming through the trenches at linac based neutron generator facility, IGCAR
Usha Pujala, L Thilagam, TS Selvakumaran, DK Mohapatra, E Alagu Raja, KV Subbaiah, R Baskaran
October-December 2011, 34(4):262-266
DOI
:10.4103/0972-0464.106194
Shielded LINAC hall has been built to accommodate a radio frequency quadrupole (RFQ) linear accelerator (LINAC) based pulsed neutron generator at RSD, IGCAR. The concrete neutron shield wall thickness for the LINAC hall is finalized by adopting NCRP-51 methodology. The dimensions of the trenches and labyrinth are decided based on the neutron generator installation requirements. As per the AERB safety criteria, the radiation dose levels in the occupancy area should be less than 1μSv/h. However, the refined dose estimate with the inclusion of actual trench and labyrinth dimensions indicates an increased dose rate of ~3.10 μSv/h in LINAC control room. Hence, the control room is declared as controlled area. Additional shielding has been proposed for the trenches and labyrinth to make the control room as full occupancy area. For designing the additional shielding, experimental and theoretical analyses are needed to estimate the radiation streaming through the trenches and labyrinth. To start with, the neutron streaming through trenches have been studied using 185 GBq (5Ci)
241
Am-Be neutron source for qualifying the trenches. The
241
Am-Be source position is selected at the trench entrance such that it contributes the same neutron flux as that of neutron generator. Neutron dose rate and spectral measurements have been carried out at five locations along the trench from the entrance (LINAC hall side) to the exit (Control room side) of the trench.The experimental results are validated with the theoretical calculations using Monte Carlo N particle (MCNP) code. The analysis shows that the trenches are having a dose reduction factor better than 800 with respect to that of entrance dose. The observed dose rate at the trench exit is found to be less than 450nSv/h. In this paper, both the theoretical and experimental neutron streaming analyses through the trenches of LINAC hall are presented.
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ORIGINAL ARTICLES
Preliminary study on the measurement of background radiation dose at Antarctica during 32
nd
expedition
AK Bakshi, Rupali Pal, Ajay Dhar, MP Chougaonkar
October-December 2013, 36(4):164-167
DOI
:10.4103/0972-0464.142393
A significant proportion (10%) of the natural background radiation is of cosmic origin. Cosmic ray consists of gamma, protons, electrons, pions, muons, neutrons and low Z nuclei. Due to the geomagnetic effect, cosmic radiation levels at poles are higher. As a consequence, personnel working in Antarctica (or Arctic) are subjected to high level of cosmic radiation. The present study gives the details of the estimation of background radiation (neutrons, gamma and electrons) dose rate around the Indian station at Antartica named "Bharati" measured during 32
nd
Indian scientific expedition to Antarctica (32
nd
INSEA). The measurement was carried out by passive dosimeters such as TLDs and CR-39 and active dosimeter such as RadEye G portable gamma survey meter. Gamma and electron components were measured using TLDs and survey meter, whereas CR-39 SSNTDs and neutron sensitive TLDs were used for neutron measurements. These detectors were deployed at few selected locations around Bharati station for about 2 months during summer expedition. The neutron detectors used in the study were pre-calibrated with
241
Am-Be fast/thermal neutron source. The fast neutron dose rate measured based on CR-39 detector was found to about 140-420 nSv/h. The gamma dose rate evaluated by TLDs/survey meter are in the range of 290-400 nSv/h.
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7
2,910
266
Assessment of natural radioactivity in the sea-beaches of Bangladesh
Shyamal Ranjan Chakraborty, Md Kowsar Alam
January-March 2014, 37(1):6-13
DOI
:10.4103/0972-0464.146451
The present research work was aimed to study the ambient radiation environment of the most popular sea-beaches of Bangladesh. The average activity concentrations of radioactive elements such as
232
Th,
238
U and
40
K of beach sand samples were measured by gamma-ray spectrometry using an HPGe detector and found to be higher than the internationally accepted values. The absorbed γ dose rate levels of the study areas are similar to other monazite sand-bearing high background radiation areas (HBRAs) of southern and southwestern coastal regions of India and of the world. The estimated values of the radiological parameters of the present study areas were also higher than the internationally accepted values. Hence, Cox's bazaar, Kuakata and Potenga sea-beach regions can be considered as HBRAs and potential zones for monazite like radioactive sand.
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7
4,053
458
Estimation of annual effective dose rate due to the ingestion of the primordial radionuclide
40
K for the population around the Kalpakkam nuclear site, Tamil Nadu, India
Pew Basu, R Sarangapani, K Sivasubramanian, B Venkatraman
January-June 2015, 38(1):14-22
DOI
:10.4103/0972-0464.162827
A study was carried out to estimate the ingestion dose for the general population residing around Kalpakkam nuclear site due to
40
K activity in the fresh and cooked food samples collected from the surrounding areas. For the estimation of specific activity of
40
K, food samples consisting of 31 numbers of market basket samples (MBS) and 33 numbers of duplicate diet samples (DDS) were collected, conditioned, and analyzed by gamma spectrometry. The annual effective dose (AED) received by the population was estimated based on
40
K activity in the food samples, food consumption data, and ICRP model. Uncertainty associated with the estimates was quantified based on the guide to the expression of uncertainty in measurement framework approach. The
40
K specific activity in MBS ranged from 10.44 ± 1.11 to 129.00 ± 13.64 Bq/kg fresh weight. Similarly, the
40
K specific activity in DDS ranged from 10.85 ± 1.10 to 60.71 ± 6.15 Bq/kg fresh weight. The AED due to the ingestion of
40
K estimated based on MBS was 93.81 ± 7.30 μSv/year. Similarly, the AED due to the ingestion of
40
K estimated based on DDS was 33.47 ± 0.79 μSv/year among males and 26.31 ± 0.62 μSv/year among females.
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Comparison of radiation shielding properties of some coordination polymers
N Nagaraja, HC Manjunatha, L Seenappa, KN Sridhar, HB Ramalingam
Oct-Dec 2019, 42(4):150-158
DOI
:10.4103/rpe.RPE_27_19
We have studied the X-ray and gamma radiation shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, mean free path, half-value layer, tenth-value layer, effective atomic numbers, electron density, exposure buildup factors, specific gamma-ray constant, and mechanical properties in some coordination polymers such as lead monoclinic-(I), lead monoclinic-(II), lead tetragonal, azelato barium (II) polymer, 1-D coordination barium polymer (I), helical lead (II) coordination polymer, calcium bromide polymer (I), calcium bromide polymer (II), 1D-cadmium coordination polymer, and 2D-cadmium coordination polymer. We have also studied the neutron shielding properties in the same coordination polymers. From the detailed study, it is clear that helical lead (II) coordination polymer is a good absorber for X-ray and gamma radiation. The attenuation parameters for neutron are higher for 1D coordination barium polymer (I) compared to that of other studied polymers. This work is useful in the field of radiation shielding.
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Online since 25th June, 2011