Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AIR POLLUTION, RADIOACTIVE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
PubMed2003

Bioindication of the anthropogenic effects on micropopulations of Pinus sylvestris, L. in the vicinity of a plant for the storage and processing of radioactive waste and in the Chernobyl NPP zone.

Results of a comparative analysis of the frequency and spectrum of cytogenetic anomalies are presented for reproductive (seeds) and vegetative (needles) samples taken from Scotch pine (Pinus sylvestris, L.) micropopulations growing at sites with differing levels of radioactive contamination in the Chernobyl NPP 30 km zone, and at the location of a facility for the processing and storage of radioactive wastes (the 'Radon' LWPE, near the town of Sosnovy Bor in the Leningrad Region). The data obtained indicate the presence of genotoxic contaminants in the environment of the tree micropopulations. Chemical toxins make the main contribution to the environmental contamination in the Sosnovy Bor area as compared with the influence of ionising radiation in the Chernobyl 30 km zone. The higher radioresistance of seeds of Scotch pine growing on the area of the 'Radon' LWPE and in the centre of Sosnovy Bor town was revealed with acute gamma-radiation.

Air Pollution, Radioactive↗
PubMed2005

Radon exhalation of cementitious materials made with coal fly ash: Part 1--scientific background and testing of the cement and fly ash emanation.

Increased interest in measuring radionuclides and radon concentrations in fly ash, cement and other components of building products is due to the concern of health hazards of naturally occurring radioactive materials (NORM). The current work focuses on studying the influence of fly ash (FA) on radon-exhalation rate (radon flux) from cementitious materials. The tests were carried out on cement paste specimens with different FA contents. The first part of the paper presents the scientific background and describes the experiments, which we designed for testing the radon emanation of the raw materials used in the preparation of the cement-FA pastes. It is found that despite the higher (226)Ra content in FA (more than 3 times, compared with Portland cement) the radon emanation is significantly lower in FA (7.65% for cement vs. 0.52% only for FA).

Air Pollutants, Radioactive↗
PubMed2004

Influence of radioactive aerosol and biological parameters of inhaled radon progeny on human lung dose.

The present work focuses on assessing the influence of biological and aerosol parameters on human lung dose. The dose conversion factor (DCF), which gives the relationship between the effective dose and the potential alpha energy concentration of inhaled short-lived radon progeny (218Po, 214Pb, 214Bi/214Po) is estimated using a dosimetric approach related to the International Commission on Radiological Protection(ICRP). The calculations are based on the measurements of the distribution of activity size of indoor radon progeny, their unattached fraction (f(b)) and potential alpha energy concentration (E). These experimental data are measured using a low-pressure cascade impactor and a wire-screen diffusion battery. Because of the short half-lives of the investigated nuclides, modifications that simplify the dose calculation are possible. The radioactive aerosol and biological parameters are varied in order to assess the DCF arising from the uncertainty of these parameters. The main emphasis is on the variation of the ventilation rate, breathing mode, critical cells for the induction of lung cancer and the parameters of the attached and unattached activity size distribution of the radon progeny. The investigation shows that the DCF is more than a factor of two higher than the values recommended by the ICRP, namely 3.9 mSv WLM(-1) for the public and 5.1 mSv WLM(-1) for working places. The dose results for indoor aerosol conditions are in the range 2.3-2.6 mSv WLM(-1) depending on the breathing mode.

Administration, Inhalation↗
PubMed1995

Thorium lung burdens of mineral sands workers.

Thorium lung burdens have been measured in workers in the dry separation plants operated by the mineral sands industry in Western Australia. The data have been compared with historical employment records of the worker's exposure to thorium-bearing airborne dusts in order to assess the reliability of personal air sampling and with the predictions of the new Task Group lung model. The thoron exhaled in the breath of 62 workers was measured using a double filter tube. Six of the workers also underwent in-vivo gamma counting to determine their thorium lung burden. A thoron exhalation rate of 4.7% was obtained from a comparison of the two data sets. The estimated thorium lung burdens from the thoron-in-breath measurements had a geometric mean value of 10 Bq. The workers had a geometric mean employment period in the industry of 9.2 y and a geometric mean total inhaled alpha activity of 9,000 Bq, estimated from contemporary personal air sampling data and a retrospective assessment of previous workplace conditions. This exposure corresponds to a mean daily intake of 232Th of 0.45 Bq. Predictions from the new Task Group lung model indicate that, for the 45 workers with a thorium lung burden in excess of the minimum detectable level (6 Bq), the daily intake of 232Th is a factor of 1.6 higher than expected. This result suggests that previous intake of radioactive dust was higher than generally assumed for some workers. The application of the new Task Group lung models to the bioassay data results in an estimated mean annual committed effective dose for the workers of 8 mSv. Two workers (3%) were found to have been exposed for many years in excess of the 50 mSv y-1 annual limit for occupational exposure, while eight workers (13%) exceeded the ICRP's proposed new occupational standard of an average of 20 mSv y-1. All eight had been employed for more than 6 y and the majority of their exposure was attributed to early employment years, prior to extensive workplace improvements in dust control.

Air Pollutants, Radioactive↗
PubMed1999

Radiocaesium and radiostrontium uptake by turnips and broad beans via leaf and root absorption.

One of the immediate consequences of massive radioisotope release into the atmosphere is contamination of the biosphere. This contamination can affect plants either by direct deposition onto the leaves, or by contaminating the soil followed by absorption by the roots. Knowledge of the efficacy of the two routes of radionuclide incorporation into the food chain is fundamental to understanding the mechanisms by which radioactive contamination reaches man. The present work analyzes the incorporation of 134Cs and 85Sr via root and leaf uptake into the parts consumed by man, for two very different crops: turnip (Brassica napus) and broad bean (Vicia faba). The root uptake studies consider the available soil fraction for these two radionuclides, and indicate greater availability for 85Sr than for 134Cs which is fixed rapidly in the soil. For the study of leaf uptake, leaves were contaminated at three different stages of plant growth; the results indicate an inverse dependence of the transfer coefficients on the time elapsed from the moment of the contamination to harvesting of the edible parts.

Air Pollutants, Radioactive↗
PubMed2004

Kalman filtration of radiation monitoring data from atmospheric dispersion of radioactive materials.

A Kalman filter method using off-site radiation monitoring data is proposed as a tool for on-line estimation of the source term for short-range atmospheric dispersion of radioactive materials. The method is based on the Gaussian plume model, in which the plume parameters including the source term exhibit a 'random walk' process. The embedded parameters of the Kalman filter are determined through maximum-likelihood estimation making the filter essentially free of external parameters. The method is tested using both real and simulated radiation monitoring data. For simulated data, the method is shown to retrieve the embedded parameters employed in generating the data and to reconstruct the plume model parameters, including the source term. When tested against experimental radiation monitoring data the method is found accurately to uncover the known source term.

Air Movements↗
PubMed1991

Perceived susceptibility and self-protective behavior: a field experiment to encourage home radon testing.

Tested in a field experiment (N = 647) the hypothesis that perceptions of personal susceptibility are important in decisions to test one's home for radioactive radon gas. Experimental group subjects received a personal telephone call to tell them they lived in a high-risk area and a personal letter to reinforce the telephone message. After the intervention, experimental subjects were significantly more likely than minimal-treatment subjects to acknowledge the possibility of high radon levels in their homes. Perceptions of susceptibility and illness severity were significantly correlated with orders of radon test kits and with testing intentions. Nevertheless, there were no differences between groups in test orders or intentions. Results are discussed in terms of the difficulty of getting people to acknowledge susceptibility and the factors other than risk perceptions that influence self-protective behavior.

Air Pollutants, Radioactive↗
PubMed1987

Radionuclide monitoring in Northern Ireland of the Chernobyl nuclear reactor accident.

Northern Ireland received higher radiation doses due to the radionuclide contamination from the Chernobyl nuclear reactor accident than did the south of England. Levels of radioactive iodine ((131)I) and caesium ((137)Cs) in cows' milk in Northern Ireland increased to 166 and 120 Bq/l respectively in May 1986, but had decreased by factors of one million, and of twenty-five, respectively, by 1 September 1986. The resultant radiation doses represent less than one per cent of those received by a Northern Ireland individual over a period of 40 years from natural background radiation sources. The added risk to any individual from the Chernobyl accident will therefore be very small and may best be judged in the context of the enormously greater risk of death due to potentially preventable diseases, such as smoking-related lung cancer, and coronary heart disease.

Adult↗
PubMed2001

Natural radioactivity and gamma dose from Sri Lankan clay bricks used in building construction.

The specific radioactivity concentrations of 226Ra, 232Th and 40K have been determined by gamma ray spectrometry with an HPGe detector in clay brick samples from kiln sites located in 17 towns. The average values of the measured activities are 35, 72, and 585 Bq kg(-1), respectively, for the above radionuclides. The average estimated radium equivalent concentration is 183 Bq kg(-1) and is comparable with reported values for many countries in the world. This value and the value obtained from the criteria formula suggest that the use of local clay bricks do not pose a radiological hazard. The calculated average absorbed dose rate in air within buildings was found to be 102 nGy h(-1) while the population weighted indoor annual effective dose was 0.20 mSv.

Air Pollutants, Radioactive↗
PubMed1988

Continuous monitoring for airborne alpha emitters in a dusty environment.

Disposal of radioactive wastes in underground facilities requires continuous monitoring for airborne radioactive materials, both on the surface and underground. In addition to a natural background of nonradioactive and radioactive aerosols, there may be a sizeable dust contribution from ongoing work such as mining and vehicular traffic. In the monitoring of alpha-emitting radionuclides, these aerosols may lead to self-absorption in the source and a deterioration of the energy spectrum of the detected alpha particles. In this paper, the influence of a realistic background aerosol on the performance of an alpha monitoring system is evaluated theoretically. It is shown that depositing alpha emitters and background aerosol on a surface for counting leads rapidly to a considerable loss of counts, a deterioration of the alpha spectra, an eventual saturation of the count rates, and interference from the natural background of Rn daughters.

Air Pollution, Radioactive↗
PubMed1978

Airborne concentration of I-131 in a nuclear medicine laboratory.

This study measures the airborne radioactivity during the handling of millicurie quantities of I-131 in the liquid and capsule form. The data indicate there is significant airborne activity when bottles containing 100--145 mCi of liquid I-131 are opened, and that the Nuclear Regulatory Commission level for airborne activity of I-131 in restricted areas (9 X 10(-9) muCi/ml) is exceeded. However, the airborne activity of I-131 is below the Nuclear Regulatory Commission level for restricted areas when 100-mCi quantities of I-131 in the capsule form are used, or during handling of liquid I-131 in the 20- to 30-mCi range. Thyroid counting is a better method than film badge for monitoring the personnel.

Air Pollutants↗
PubMed1992

Post-Chernobyl accident radioactivity measurements in the Comunidad Autonoma de Valencia, Spain.

Increased atmospheric radioactivity after the accident in Chernobyl was first detected on air filters. Measurements were begun in Valencia on May 2, 1986, with the maximum activity being observed around May 3-4, 1986. As a consequence of this accident, annual campaigns of measurements on migrating birds (several species of aquatic birds and song-thrushes) were started. The data corresponding to the campaign immediately after the accident (1986/87) show a generalized contamination (approximately 50% of the measured specimens). Significant levels of 134Cs, 137Cs and 110Agm were found. It is important to note that 110Agm is only present in Aythya ferina. In the successive campaigns in 1988/89 and 1989/91 few samples were found to be contaminated and only 137Cs was identified. Strontium-90 was measured and identified in some specimens, mainly in their bones.

Accidents↗
PubMed1992

Study on the environmental behavior of Chernobyl-derived radionuclides in Kyushu Island, Japan.

The environmental behavior of Chernobyl-derived radionuclides in Kyushu Island was investigated for one month after the accident. The radioactivity level in airborne dusts was two orders of magnitude lower than that observed in Western Europe. The distribution of 131I in airborne dusts shifted to a larger particle size compared with other radionuclides. The radionuclide concentration in seaweeds varied depending on the geographical situation where the sampling was done. The biological half-lives in red algae were calculated to be 17.4 d and 32.9 d for 131I and 103Ru, respectively. The concentration factors in red algae were estimated to be 3 x 10(3) and 5 x 10(3) for 131I and 103Ru, respectively. The cooking effect of 131I in seaweeds and the committed effective dose equivalent through ingestion of seaweed were also evaluated.

Accidents↗
PubMed2001

The use of a modified technique to reduce radioactive air contamination in aerosol lung ventilation imaging.

The aim of this study was to reduce airborne contamination resulting from the use of aerosols in lung ventilation scintigraphy. Lung ventilation imaging is frequently performed with 99mTc-diethylenetriaminepentaacetate aerosol (DTPA), derived from a commercial nebuliser. Airborne contamination is a significant problem with this procedure; it results in exposure of staff to radiation and can reduce gamma camera performance when the ventilation is performed in the camera room. We examined the level of airborne contamination resulting from the standard technique with one of the most popular nebuliser kits and tested a modification which significantly reduced airborne contamination. Air contamination was measured while ventilating 122 patients. The modified technique reduced air contamination by a mean value of 64% (p = 0.028) compared with the standard control technique. Additionally, differences in contamination were examined when a mask or mouthpiece was used as well as differences between operators. A simplified method of monitoring air contamination is presented using a commonly available surface contamination monitor. The index so derived was proportional to air contamination (r = 0.88). The problems and regulations associated with airborne contamination are discussed.

Aerosols↗
PubMed1985

Radiological health implications of lead-210 and polonium-210 accumulations in LPG refineries.

Radon-222, a naturally occurring radioactive noble gas, is often a contaminant in natural gas. During fractionation at processing plants, Radon tends to be concentrated in the Liquified Petroleum Gas (LPG) product stream. Radon-222 decays into a number of radioactive metallic daughters which can plate out on the interior surfaces of plant machinery. The hazards associated with gamma-emitting short-lived radon daughters have been investigated previously. The present work reports an analysis of the hazards associated with the long-lived daughters; Pb-210, Bi-210, and Po-210. These nuclides do not emit appreciable penetrating radiation, and hence do not represent a hazard as long as they remain on the inside surfaces of equipment. However, when equipment that has had prolonged exposure to an LPG stream is disassembled for repair or routine maintenance, opportunities for exposure to radioactive materials can occur. This paper reports a series of measurements made on an impeller taken from a pump in an LPG facility. Alpha spectroscopy revealed the presence of Po-210, and further measurements showed that the amount on the impeller surface was well above the exempt quantity. Breathing zone measurements made in the course of cleaning the impeller showed that an inhalation exposure equivalent to breathing Po-210 at the Maximum Permissible Concentration (MPC) for 60 hours could be delivered in less than half an hour. It was concluded that maintenance and repair work on LPG and derivitive product stream equipment must be carried out with the realization that a potential radiological health problem exists.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution, Radioactive↗
PubMed2001

Determination of neutralisation rates of 218Po ions in air.

The electric charge of the radon decay product, 218Po, has an influence on its mobility characterised by the diffusion coefficient, which chiefly controls the formation of the radioactive aerosol by attachment and the plateout processes on surfaces. These processes strongly affect the dose relevant quantities like concentration and particle size distribution of the short-lived radon decay products. The neutralisation rate of the positive 218Po ions in environmental air was determined quantitatively in chamber experiments. The experimental results show the great influence of the ionisation rate and the humidity concentration on the neutralisation rate of the 218Po ions in air. The obtained neutralisation rates were described by equations, taking into account the neutralisation processes like ion recombination, charge transfer and electron scavenging. In 'normal' environmental air with an ionisation rate of 45 muR.h(-1) = 1.16 x 10(-8) C/(kg.h) and a relative humidity of 50% (T = 20 degrees C), a neutralisation rate of the 218Po ions of 1.54 x 10(-2) s(-1) was obtained. Taking into account this neutralisation rate leads to a fraction of about 51% of the Po cluster that are neutral in air.

Air Pollutants, Radioactive↗
PubMed2004

Intercomparison experiments of systems for the measurement of xenon radionuclides in the atmosphere.

Radioactive xenon monitoring is one of the main technologies used for the detection of underground nuclear explosions. Precise and reliable measurements of (131m)Xe, (133g)Xe, (133m)Xe, and (135g)Xe are required as part of the International Monitoring System for compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). For the first time, simultaneous testing of four highly sensitive and automated fieldable radioxenon measurement systems has been performed and compared to established laboratory techniques. In addition to an intercomparison of radioxenon monitoring equipment of different design, this paper also presents a set of more than 2000 measurements of activity concentrations of radioactive xenon made in the city of Freiburg, Germany in 2000. The intercomparison experiment showed, that the results from the newly developed systems agree with each other and the equipment fulfills the fundamental requirements for their use in the verification regime of the CTBT. For 24-h measurements, concentrations as low as 0.1 mBqm(-3) were measured for atmospheric samples ranging in size from 10 to 80 m(3). The (133)Xe activity concentrations detected in the ambient air ranged from below 1 mBqm(-3) to above 100 mBqm(-3).

Air Pollutants, Radioactive↗
PubMed2006

Natural radioactivity and evaluation of effective dose equivalent of granites in Turkey.

Annual effective dose equivalent due to natural gamma radiation from (238)U, (232)Th and (40)K have been evaluated from granites in Turkey. Forty samples were taken for spectrometric analysis. Specific concentrations of (238)U, (232)Th and (40)K in granite samples were determined. Spectroscopy system was used with 1.8 keV (FWHM) coaxial high purity germanium (HPGe) detector. Average values of concentrations of (238)U, (232)Th and (40)K were detected at 15.85, 33.76 and 359 Bq kg(-1), respectively. The average value of radon varies from 0.073 to 0.185 Bq m(-2) h(-1) exhalation depends on the specific concentration of uranium. The dose rate due to this highest activity which have been evaluated by a Monte Carlo transport calculations does not exceed 0.4 mSv a(-1).

Air Pollutants, Radioactive↗