Mass Exhalation Rate Research Articles

MEASUREMENT OF INDOOR RADON-THORON IN AIR AND EXHALATION FROM SOIL IN THE ENVIRONMENT OF WESTERN HARYANA, INDIA.

Measurement of indoor radon and thoron is important because the inhalation of radon-thoron and their daughters contributes more than 50 % of the total dose from natural sources. One of the important parameters to find out the contribution of soil and building materials towards indoor radon is radon exhalation rates, which can be used for estimation of indoor radon levels. The indoor radon and thoron levels from the air and radon exhalation rates from soil samples collected from two districts (Hisar and Fatehabad) of Western Haryana are measured using pin-hole-based radon-thoron dosimeter and LR-115 solid-state nuclear track detector by canister technique. The results show that the indoor radon and thoron levels from Hisar district varied from 11 to 112 and 11 to 80 Bq m-3, while for Fatehabad district from 5 to 24 and 59 to 105 Bq m-3, respectively, in summer season. In winter season, indoor radon and thoron levels from Hisar district varied from 15 to 43 and 32 to 102 Bq m-3, while for Fatehabad district from 18 to 31 and 11 to 80 Bq m-3, respectively. The indoor radon levels of 95 % locations lie well below the limit recommended by International Commission of Radiation Protection, 2011. The radon mass exhalation rate varied from 6 to 56 mBq kg-1 h-1 The radon mass exhalation rates from the soil samples were lower than the worldwide average, i.e. 56 mBq kg-1 h-1 There exists a poor correlation between indoor radon and exhalation rates. More investigations of measurement of radionuclide contents from rock and stone of study area can improve the understanding.

RADIUM AND RADON EXHALATION RATE IN SOIL SAMPLES OF HASSAN DISTRICT OF SOUTH KARNATAKA, INDIA.

The radon exhalation rate was measured in 32 soil samples collected from Hassan district of South Karnataka. Radon exhalation rate of soil samples was measured using can technique. The results show variation of radon exhalation rate with radium content of the soil samples. A strong correlation was observed between effective radium content and radon exhalation rate. In the present work, an attempt was made to assess the levels of radon in the environment of Hassan. Radon activities were found to vary from 2.25±0.55 to 270.85±19.16 Bq m-3 and effective radium contents vary from 12.06±2.98 to 1449.56±102.58 mBq kg-1 Surface exhalation rates of radon vary from 1.55±0.47 to 186.43±18.57 mBq m-2 h-1, and mass exhalation rates of radon vary from 0.312±0.07 to 37.46±2.65 mBq kg-1 h-1.

A Study of Radium Concentration and Radon Exhalation Rate in Soil Samples from Kassala Town, Sudan Using SSNTDs

In this work, we are presenting the results of radium concentration, surface and mass radon exhalation rates for a number of 209 soil samples collected from different locations of Kassala town, Sudan, by using the can technique, containing CR-39. The values of radium concentrations from soil samples were found to be ranging from 3.9 to 34.2 Bq.kg-1, with an average of 16.3 ± 1.6 Bq.kg-1. The surface and mass exhalation rates of radon were found to be from 0.84 to 7.35 Bq.m-2.h-1 and 17 to 148 mBq.kg-1.h-1, with an averages of 3.50 ± 0.35 Bq.m-2.h-1 and 70 ± 7 mBq.kg-1.h-1, respectively for the studied soil samples. From the results of this study we found that, there was a good correlation between radium concentration and radon exhalation rates in soil samples. The values of radium concentration determined in soil samples are less than the permissible value of 370 Bq.kg-1 recommended by Organization for Economic Cooperation and Developments, which is acceptable for safe use. Thus, results reveal that the area is safe as far the health hazard effects are concerned. Finally we compare our results with similar findings in different regions of Sudan and among other Countries.

Radiometric analysis of volcanic tuff stones used as ornamental and structural building materials in Turkey and evaluation of radiological risk

Volcanic tuff stones are widely used to coat the interior and exterior surfaces of buildings for ornamental purposes in the construction industry in Turkey, and are also used as structural material in the construction of masonry buildings, especially in the Cappadocia region, which is a popular tourist destination. In this study, seventy-six volcanic tuff stone samples collected from different quarries located in different geographical regions in Turkey were surveyed for radiometric analysis, and the radiological risk to human health caused by ionizing radiation from natural radionuclides in the volcanic tuff stone samples was evaluated. The activity concentrations of 238 U, 232 Th, 226 Ra and 40 K analyzed in volcanic tuff stone samples were very variable, ranging from 3 to 389, 8 to 401, 2 to 263 and 99 to 2107 Bq kg -1 , respectively. The emanation coefficient and mass exhalation rate of 222 Rn measured for the volcanic tuff samples ranged from 2 to 68% with an average of 34%, and 1 to 194 μ Bq kg -1 s -1 with an average of 43 μ Bq kg -1 s -1 , respectively. The external (gamma) and internal (alpha) hazard indices, indoor absorbed gamma dose rate and the corresponding annual effective dose were estimated to evaluate the potential radiological risk to human health. The results showed that all of the surveyed volcanic tuff stone samples can be used as covering building materials for ornamental or insulating covering purposes. However, the use of some volcanic tuff stone samples as structural building materials should be restricted.

Study of Radium and Radon Exhalation Rate in Soil Samples from Areas of Northern Rajasthan

Abstract The health hazards of the radioactive gas radon on the humans are well known. Radon from soil gas is the main cause of radon problems. The “can technique” using LR-115 type II plastic track detectors have been used for the measurement of radon exhalation rate in soil samples from areas of northern Rajasthan, India. The radon exhalation values were calculated in terms of mass (EM) and area (EA). The mass exhalation rate in these samples vary from 8.27 to 23.19 mBq kg-1 h-1 with an average of 14.96 mBq kg-1 h-1, whereas, surface exhalation rate vary from 273.80 to 768.04 mBq m-2 h-1 with an average of 495.32 mBq m-2 h-1. The radium concentration ranges from 6.88 to 19.31 Bq kg-1 with an average value of 12.45 Bq kg-1. The observed values of effective radium concentration in all the soil samples are less than the permissible value of 370 Bq kg-1 as recommended by Organization for Economic Cooperation and Development (OECD). Hence, the result shows that this area is safe as for as the health hazard effects of radium and radon exhalation rate are concerned.

Measurement of Uranium Concentrations, Radium Content and Radon Exhalation Rate in Iraqian Building Materials Samples

Uranium, radium concentration and radon exhalation rate in twenty one building material samples collected from markets of Iraq were measured using the sealed-can technique based on the CR-39 SSNTDS. The values of effective radium content were found to vary from (0.037 to 4.986) Bq/kg with a mean value of 0.745Bq/kg. The values of mass exhalation rates of radon vary from (0.688 ×10−8 to46.910×10−8) Bq/kg.day with a mean value 7.012×10−8Bq/kg.day, while the surface exhalation rates of radon vary from (0.344×10−6to23.472×10−6)Bq/m2.day with a mean value of 3.508×10−6Bq/m2.day. Uranium content in these samples has been found, it is varying from 0.074 to 5.055 ppm with a mean value of 0.755ppm. The mean values of radon exhalation rate, radium content and uranium concentration in building material samples of study area were found well below the values of 57.600 mBq/m2.h , 370 Bq/kg and 3ppm, respectively.

A study of radon emitted from building materials using solid state nuclear track detectors

Radon is a natural radioactive gas derived from geologic materials. Inhalation of the short-lived decay products of radon has been linked to an increase in the risk of developing lung cancers if present at elevated levels. Accurate knowledge of exhalation rate plays an important role in characterization of the radon source strength in some building materials.For this purpose, in this study the Can Technique using CR-39 plastic track detectors was used to measure radium content and exhalation rates of radon in building samples collected from Jizan districts-a province in southern Saudi Arabia. The values of effective radium content are found to vary from 0.21 to 2.2 Bq kg−1 with a mean value of 0.92 Bq kg−1 and a standard deviation of 0.81. All the values of radium content in all samples under test were found to be quite lower than the permissible value of 370 Bq kg−1 recommended by Organization for Economic Cooperation and Development. The values of mass exhalation rates of radon vary from 1.6 to 16.7 mBq kg−1 h−1 with a mean value of 6.9 mBq kg−1 h−1, while the surface exhalation rates vary from 29.7 to 998.9 mBq m−2 h−1 with a mean value of 219.6 mBq m−2 h−1. Alpha index and annual effective doses have also been estimated.

The Measurements of Natural Radioactivity, (Radon and Gamma concentrations), around the old fertilizer factory in Basrah/Iraq

Radon concentration, exhalation rate, annual effective dose, radium activity, thorium, uranium potassium and radium equivalent have been measured in the present investigation for soil in the area around the old fertilizer factory in southern of Basrah Governorate. The measurements based on CR39 track detector for passive method, RAD7 for active method and NaI(Tl) for gamma concentration measurements. Average values for radon concentration in soil were 112.04±10.76 Bq/m3 using passive technique and 104.56±6.05 Bq/m3 using RAD7. From the result of the passive technique, area and mass exhalation rates and the annual effective dose were calculated. Gamma ray spectroscopy for the soil samples were performed and found that the average concentrations of 226Ra, 232Th and 40K were 50.89 Bq/kg, 21.74 Bq/kg and 640.4 Bq/kg respectively. Gamma ray hazard indices were calculated and found they are within the world average.

Radon Concentration in Soil and Radon Exhalation Rate at Al-Dora Refinery and Surrounding Area in Baghdad

Radongas concentrations in soil samples were determined from depths (surface, 15, and 30) cm for nine locations in Al-Dora refinery and surrounding area using “sealed can technique” and CR-39 solid state nuclear track detectors. The radon concentration in surface samples ranged from 810.08 to 1380.08 Bq/m3 with an average 1137.71 Bq/m3. The radon concentration in soil at the depth 15 cm was ranged from 490.5 to 1197.52 Bq/m3 with an average 732.78 Bq/m3 and at the depth 30 cm was ranged from 362.07 to 889.53 Bq/m3 with an average 529.41 Bq/m3. The surface exhalation rate in surface soil samples ranged was 0.44, to 0.99 Bq·m-2·h-1 with average 0.61 Bq·m-2·h-1. The surface exhalation rate in soil samples at the depth 15 cm was ranged from 0.22 to 0.64 Bq·m-2·h-1 with average 0.39 Bq·m-2·h-1. The surface exhalation rate in soil samples at the depth 15 cm was ranged from 0.22 to 0.64 Bq·m-2·h-1 with average 0.39 Bq·m-2·h-1. The surface exhalation rate and the mass exhalation rate in soil samples at the depth 30 cm ranged from 0.19, to 0.48 Bq·m-2·h-1 with average 0.28 Bq·m-2·h-1. The mass exhalation rate in surface soil samples ranged from 0.09 to 0.21 Bq·kg-1·h-1 with average 0.12 Bq·kg-1·h-1. The mass exhalation rate in soil samples from depth 15 cm was ranged from 0.046 to 0.14 Bq·kg-1·h-1 with average 0.08 Bq·kg-1·h-1. The mass exhalation rate in soil samples at the depth 30 cm was ranged from 0.042 to 0.1 Bq·kg-1·h-1 with average 0.06 Bq·kg-1·h-1.

Radon exhalation rates of some granites used in Serbia

In order to address concern about radon exhalation in building material, radon exhalation rate was determined for different granites available on Serbian market. Radon exhalation rate, along with mass exhalation rate and effective radium content were determined by closed chamber method and active continuous radon measurement technique. For this research, special chambers were made and tested for back diffusion and leakage, and the radon concentrations measured were included in the calculation of radon exhalation. The radon exhalation rate ranged from 0.161 Bq/m2h to 0.576 Bq/m2h, the mass exhalation rate from 0.167 Bq/kgh to 0.678 Bq/kgh, while the effective radium content was found to be from 12.37 Bq/kg to 50.23 Bq/kg. The results indicate that the granites used in Serbia have a low level of radon exhalation.

Radon-thoron measurements in air and soil from some districts of northern part of India

Radon, thoron and their progenies in the indoor environment are considered as one of the health hazards. The alpha emitting nature of these gases made it possible to detect in indoor environment with the help of nuclear track detector techniques. The soil is the main source of indoor radon as it contains varying amounts of uranium and thorium. Thus the exhalation of radon from soil and its environmental activity needs to be studied. In the present study, the measurement of the indoor radon-thoron from the indoor environment and exhalation from soil are carried out using solid state nuclear track detector technique from Sirsa and Bhiwani districts of northern part of India. The canister technique was used to measure the radon ex- halation rate from the soil samples collected from the study area and pinhole based radon-thoron dosimeters were used to measure indoor radon and thoron concentration. The results show that indoor radon concentration varied from 9 to 28 Bq/m3, with an average of 18.9 Bq/m3 and from 5 to 21 Bq/m3, with an average of 13.8 Bq/m3, for Bhiwani and Sirsa, respectively. Similarly, thoron concentration varied from 14 to 48 Bq/m3, with average of 28.9 Bq/m3 and 27 to 54 Bq/m3, with the average of 39.0 Bq/m3, for Bhiwani and Sirsa, respectively. The mass exhalation rates from soil samples were also measured, to estimate their contribution to indoor radon. A correlation study was carried out between soil exhalation rates and indoor radon concentration.

The Effect of Grain Size on Radon Exhalation Rate in Natural-dust and Stone-dust Samples

Radiation dose to human population due to inhalation of radon and its progeny contributes more than 50% of the total dose from the natural sources which is the second leading cause of lung cancer after smoking. In the present work the dependence of radon exhalation rate on the physical sample parameters of stone dust and natural dust were studied. The samples under study were first crushed, grinded, dried and then passed through sieves with different pore sizes to get samples of various grain sizes (μm). The average value of radon mass exhalation rate is 5.95±2.7 mBqkg-1hr-1 and average value of radon surface exhalation rate is 286±36 mBqm-2 hr-1 for stone dust, and the average value of radon mass exhalation rate is 9.02±5.37 mBqkg-1hr-1 and average value of radon surface exhalation rate is 360±67 mBqm-2 hr-1 for natural dust. The exhalation rate was found to increase with the increase in grain size of the sample. The obtained values of radon exhalation rate for all the samples are found to be under the radon exhalation rate limit reported worldwide.

Measurement of Radon Exhalation Rate in Sand Samples from Gopalpur and Rushikulya Beach Orissa, Eastern India

Natural radioactivity is wide spread in the earth's environment and exists in various geological formations like soils, rocks, water and sand etc. The measurement of activities of naturally occurring radionuclides 226Ra, 232Th and 40K is important for the estimation of radiation risk and has been the subject of interest of research scientists all over the world. Building construction materials and soil beneath the house are the main sources of radon inside the dwellings. Radon exhalation rate from building materials like, cement, sand and concrete etc. is a major source of radiation to the habitants. In the present studies radon exhalation rates in sand samples collected from Gopalpur and Rushikulya beach placer deposit in Orissa are measured by using “Sealed Can technique” with LR-115 type II nuclear track detectors. In Samples from Rushikulya beach show radon activities varying from 389 ± 24 to 997 ± 38 Bq m-3 with an average value of 549 ±28 Bq m-3. Surface exhalation rates in these samples are found to vary from 140 ± 9 to 359 ± 14 mBq m-2 h-1with an average value of 197 ±10 mBq m-2 h-1, whereas, mass exhalation rates vary from 5 ± 0.3 to 14 ± 0.5 mBq kg-1 h-1 with an average value of 8 ± 0.4 mBq kg-1 h-1. Samples from Gopalpur radon activities are found to vary from 371 ± 23 to 800 ± 34 Bq m-3 with an average value of 549 ± 28 Bq m-3. Surface exhalation rates in these samples are found to vary from 133 ± 8 to 288 ± 12 mBq m-2h-1 with an average value of 197 ± 10 mBq m-2 h-1, whereas, mass exhalation rates vary from 5 ± 0.3 to 11 ± 1 mBq kg-1 h-1 with an average value of 8 ± 0.4 mBq kg-1 h-1.

Measurement of radon exhalation rates from some building materials used in Serbian construction

The rates of radon exhalation from building materials available on the Serbian market were measured using RAD7 device. Fitting the growth curves of radon activity concentration provided the information on radon exhalation rates from the samples. The results were quite low and they ranged from 1.4 to 855 mBq m−2 h−1 for surface exhalation rate and from 1.3 to 11.4 mBq kg−1 h−1 for mass exhalation rate. The effect of moisture on radon exhalation was confirmed. For powdered samples with dimensions smaller than radon diffusion length, the mass exhalation rate is independent of sample mass and its exhalation area.

Distribution of natural radionuclide along Main Central Thrust in Garhwal Himalaya

Study of natural radionuclide is important to assess the radiation level in a particular area. Radionuclide present in earth's crust is different for different geological areas because of the variety of soil and rocks present in a particular area. In present study, the estimation of natural radionuclides have been carried out along the Main Central Thrust (MCT) in Uttarkashi, Budhakedar, Ukhimath and Healang regions of Garhwal Himalaya, India. The large variations in the radionuclide distribution have been estimated along the Main Central Thrust. The 226Ra, 232Th and 40K contents in MCT area varies from 8 ± 1 Bq.kg−1 to 285 ± 28 Bq.kg−1 with an average of 64 Bq.kg−1, 7 ± 1 Bq.kg−1 to 136 ± 15 Bq.kg−1 with an average 69 Bq.kg−1 and 115 ± 18 Bq.kg−1 to 1588 ± 162 Bq.kg−1 with an average 792 Bq.kg−1, respectively. The radon exhalation rate and radon concentration in the soil of study area varies from 2.20 × 10−5 Bq.kg−1h−1 to 3.2 × 10−5 Bq.kg−1h−1 and 287 Bq/m3 to 417 Bq/m3, respectively. It was observed that the distribution of natural radionuclide in the soil of study area is not uniform and concentrated along geological active region. These values of radionuclide and radon mass exhalation rate may be used as baseline data for further study in the area.

Ventilation effect on indoor radon–thoron levels in dwellings and correlation with soil exhalation rates

This paper reports the measurements of indoor radon and thoron concentrations in selected Northern Indian dwellings (differing in ventilation rate). These were carried out using single entry pin hole based radon thoron dosimeters. In order to correlate the indoor levels with source term, the radon and thoron exhalation rates from soil samples collected from the same dwellings were also measured. Active measurement techniques with scintillation radon monitor and scintillation thoron monitor were used for exhalation measurements from soil sample. For thoron exhalation rate measurements, a small volume chamber was used. The indoor radon and thoron concentration in different rooms varied from 14 to 97 Bq/m3 and 23 to 189 Bq/m3, respectively. The radon mass exhalation and thoron mass emanation rates of soil samples varied from 28.2 to 91.2 mBq/kg/h and 3.42 to 12.1 mBq/kg/h, respectively. A weak correlation was found between indoor concentration and soil exhalation rates for these dwellings. Indoor radon concentrations from various rooms in the dwellings were lower than the limit (100 Bq/m3) recommended by WHO (2009).

Radon exhalation rates from some building materials used in Sudan

Measurements of radon concentration, surface and mass exhalation rates were made for 12 types (264 measurements) of building material samples frequently used in Sudan. In this survey, we used the can technique, containing CR-39, to estimate the radon exposure from building materials. The results of radon concentrations in the selected building materials ranged from 506 ± 79 Bq.m−3 in mud bricks of Aroma area to 128 ± 39 Bq.m−3 in ceramic material. The surface and mass exhalation rates ranged from 949 ± 70 mBq.m−2.h−1, 11.25 ± 1.76 mBq.kg−1 h−1 to 240 ± 35 mBq.m−2 h−1, 2.84 ± 0.87 mBq.kg−1.h−1, respectively. The effective dose was calculated that ranged from 3.59 ± 1.10 mSv.y−1 to 14.21 ± 2.23 mSv.y−1, for ceramic and mud materials, respectively. These results agreed with similar findings that mud contributes in a higher indoor concentration than the other investigated materials, mud was found to constitute an effective dose above the action level as quoted by the International Commission on Radiological Protection (ICRP).

Measurement of fertilizers induced radioactivity in tobacco plants and elemental analysis using ICAP–AES

It is widely accepted that tobacco smoke is the leading cause of lung cancer worldwide. The alpha radioactive content present in tobacco smoke and increasing number of lung cancer cases explain the importance of investigation. The use of different fertilizers may cause alteration in the metabolism of plants causing different response towards uptake of different element and radionuclides. In the present study, the estimation of alpha radioactivity induced by use of different fertilizers in tobacco leaves was made using solid state nuclear track detector (LR-115) to identify the relative presence of radionuclides in the plants. The radon exhalation rates from the tobacco plant were carried out to confirm the presence of radium or emission of radon from plant. The elemental analysis of tobacco plant by inductively coupled argon plasma atomic emission spectrometry provides a way to understand the difference occurred in metabolism caused by the use of fertilizers. The alpha track densities were found to vary with nature of fertilizers added to the soil and an increase was also observed with time. The radon mass exhalation rates in various tobacco plants were found to vary with type of fertilizers used.

Measurement of radon activity and exhalation rate in soil samples from Banda district, India

Radon activities and radon exhalation rates have been measured in soil samples collected from different location of Banda district of Uttar Pradesh in India using LR-115 type II solid state nuclear track detectors. Radon activity has been found to vary from (101.0) to (505.1) Bq/m 3 with an average value of (278.3) Bq/m 3 . Surface exhalation rate has been found to vary from (84.0) to (419.8) mBq/m 2 /h with an average value (231.3) mBq/m 2 /h, whereas mass exhalation rate has been found to vary from (2.1) mBq/kg/h to (10.6) mBq/kg/h with an average value of (5.8) mBq/kg/h. Effective dose from indoor inhalation exposure (radon) has been estimated, which is found to vary from (6.1) to (30.5) μSv/year with an average value of (16.8) μSv/year.

Radon exhalation rate from the building materials of Tiruchirappalli district (Tamil Nadu State, India)

Tiruchirappalli district has enriched resources of building materials such as stone, granite, sand, brick, cement, etc., which are also supplied to the neighboring districts. Since radon is considered as one of the causative factors for human lung diseases, the measurement of the radon level in these building materials is imperative for the assessment. The samples of building materials were collected from their original sources spread over Tiruchirappalli district. The sealed can technique with solid state nuclear track detector (SSNTD) was employed for the measurement of radon exhalation. The activity concentrations of radon in sedimentary rocks analyzed ranged from 13.2 Bq/m 3 to 218.0 Bq/m 3 with the geometric mean activity of 46.3 Bq/m 3 . However, radon concentrations in igneous rocks are distinctly higher than those of sedimentary rocks and ranged from 95.6 Bq/m 3 to 1140 Bq/m 3 with the geometric mean activity concentration of 392.6 Bq/m 3 . The radon exhalation from sand, brick, and cement were found to be non-uniform (sand: 119.8-656 Bq/m 3 , brick: 31-558 Bq/m 3 , cement: 172-300 Bq/m 3 ). The activity concentration of radon in these building materials follow a descending order: Granite > sand > cement > brick > sand stone. The mass and surface exhalation (E M and E A ) rates also follow the same order. The study concludes that since the radon exhalation from the building materials was less than the International Commission on Radiological Protection limit of 1500 Bq/m 3 , they do not pose any radiological risk.