RADON INHALATION EXPERIMENTS TO TEST RADON EXHALATION KINETICS.

Three experiments were conducted with a volunteer to test the kinetics of the 222Rn exhalation after a short-time exposure to an elevated 222Rn air concentration. Radon concentration in an exhaled air was measured, complemented by whole body counting of 222Rn decay products in a body. Exhaled activities are compared with the prediction of the recent ICRP biokinetic model for radon. While a rapid equilibration of the exhaled radon activity concentration with that in the air inhaled corresponded with the model, the measured 222Rn exhalation rate was significantly less than modelled. Five hours after termination of the inhalation phase, the radon concentration in the exhaled air decreased to levels expected for non-elevated indoor radon activity concentration. Whole body activities of the 222Rn decay products were found higher than expected. Inhalation of the unattached fraction or residual activity of decay products in the air inhaled may be the explanation.

National radon programmes and policies: the RADPAR recommendations.

Results from epidemiological studies on lung cancer and radon exposure in dwellings and mines led to a significant revision of recommendations and regulations of international organisations, such as WHO, IAEA, Nordic Countries, European Commission. Within the European project RADPAR, scientists from 18 institutions of 14 European countries worked together for 3 y (2009-12). Among other reports, a comprehensive booklet of recommendations was produced with the aim that they should be useful both for countries with a well-developed radon programme and for countries with little experience on radon issues. In this paper, the main RADPAR recommendations on radon programmes and policies are described and discussed. These recommendations should be very useful in preparing a national action plan, required by the recent Council Directive 2013/59/Euratom.

A fast and simple approach for the estimation of a radiological source from localised measurements after the explosion of a radiological dispersal device.

After an explosion of a radiological dispersal device, decision-makers need to implement countermeasures as soon as possible to minimise the radiation-induced risks to the population. In this work, the authors present a tool, which can help providing information about the approximate size of source term and radioactive contamination based on a Gaussian Plume model with the use of available measurements for liquid or aerosolised radioactivity. For two-field tests, the source term and spatial distribution of deposited radioactivity are estimated. A sensitivity analysis of the dependence on deposition velocity is carried out. In case of weak winds, a diffusive process along the wind direction is retained in the model.

Reassessment of individual dosimetry of long-lived alpha radionuclides of uranium miners through experimental determination of urinary excretion of uranium.

Urinary excretion of uranium of 40 uranium miners was determined by the high-resolution inductively coupled mass spectrometry method. The concentration of uranium in the urine of the miners was converted to daily excretion of (238)U either under the assumption that the daily urinary excretion is 1.6 l or daily urinary excretion of creatinine is 1.7 g and compared with the excretion of (238)U calculated with a biokinetic model. Input data to the excretion model were derived from personal three- component ALGADE dosemeters, using the component for the estimation of inhalation of long-lived alpha radionuclides. Experimentally found contents of uranium in the urine of uranium miners are generally lower than the modelled ones, which means that the dosimetric approach is conservative. The uncertainty of inhalation intakes, derived from the measurements of filters from personal dosemeters, and the uncertainty of the concentration of uranium in the urine are discussed.

Field tests using radioactive matter 2.

Results of field tests with explosive dispersal of a radioactive substance (RaS) are presented. The paper deals with tests exploiting artificial obstacles as a continuation and expansion of the tests used in this study performed in free area described previously. The essential goal of the tests was to estimate the distribution of the released RaS in the case of intentional abuse of radioactive sources and to get a set of data applicable to testing physical or mathematical models of propagation. Effects of different geometrical and meteorological conditions on the distribution of dispersed RaS were studied via the assessment of dose rate, surface and volume activities, aerosol mass and activity aerodynamic diameters. The principal results can be summarised as follows: the prevalent proportion of the activity of the radionuclide dispersed by an explosion (born by the blast wave and by air convection) is transferred to the detection system/collecting pads essentially within the first minute. Enhanced aerosol mass concentrations were also detected within the same period. The RaS carried by the blast wave passed through the polygon (50 m) within <1 s. An expected crucial impact of meteorological conditions at the moment of the explosion and shortly after was proved by the tests.

Estimates of the annual average indoor radon concentration in Telecí in the Czech Republic.

Indoor radon concentrations are subject to diurnal and seasonal variations. In order to obtain an unbiased estimate of the annual mean radon concentration, measurements made over periods less than 12 months have to be adjusted accordingly. In this paper, hourly radon measurements from one uninhabited rural house in Telecí in the Czech Republic have been analysed. The data were collected over a period of 1 y. The behaviour of the radon concentration with time and its relationship with the outdoor temperature, wind speed and atmospheric pressure have been studied. Different estimates of the annual mean radon concentration based on short-term continuous measurements have been assessed.

Retrospective determination of 137Cs specific activity distribution in spruce bark and bark aggregated transfer factor in forests on the scale of the Czech Republic ten years after the Chernobyl accident.

The (137)Cs specific activities (mean 32Bq kg(-1)) were determined in spruce bark samples that had been collected at 192 sampling plots throughout the Czech Republic in 1995, and were related to the sampling year. The (137)Cs specific activities in spruce bark correlated significantly with the (137)Cs depositions in areas affected by different precipitation sums operating at the time of the Chernobyl fallout in 1986. The ratio of the (137)Cs specific activities in bark and of the (137)Cs deposition levels yielded bark aggregated transfer factor T(ag) about 10.5×10(-3)m(-2)kg(-1). Taking into account the residual specific activities of (137)Cs in bark 20Bq kg(-1) and the available pre-Chernobyl data on the (137)Cs deposition loads on the soil surface in the Czech Republic, the real aggregated transfer factor after and before the Chernobyl fallout proved to be T*(ag)=3.3×10(-3)m(-2)kg(-1) and T**(ag)=4.0×10(-3)m(-2)kg(-1), respectively. The aggregated transfer factors T*(ag) for (137)Cs and spruce bark did not differ significantly in areas unequally affected by the (137)Cs fallout in the Czech Republic in 1986, and the figures for these aggregated transfer factors were very similar to the mean bark T(ag) values published from the extensively affected areas near Chernobyl. The magnitude of the (137)Cs aggregated transfer factors for spruce bark for the pre-Chernobyl and post-Chernobyl period in the Czech Republic was also very similar. The variability in spruce bark acidity caused by the operation of local anthropogenic air pollution sources did not significantly influence the accumulation and retention of (137)Cs in spruce bark. Increasing elevation of the bark sampling plots had a significant effect on raising the remaining (137)Cs specific activities in bark in areas affected by precipitation at the time when the plumes crossed, because the sums of this precipitation increased with elevation (covariable).

Content of uranium in urine of uranium miners as a tool for estimation of intakes of long-lived alpha radionuclides.

Uranium in the urine of 10 uranium miners (hewers), 27 members of general population and 11 family members of miners was determined by the High-Resolution ICP-MS method. Concentration of uranium in urine of the miners was converted to daily excretion of (238)U under the assumption that the daily excretion of urine is 2 l and compared with the modelled excretion of (238)U. Daily excretion of (238)U was modelled using input data from personal dosemeters from a component for measurement of intake of long-lived alpha radionuclides. A reasonable agreement between evaluated and measured values was found. The uncertainty of inhalation intakes, derived from measurements of filters from personal dosemeters, and uncertainty of concentration of uranium in urine are discussed.

Field tests using radioactive matter.

During recent years, the assessment of possible radiological consequences of a terrorist attack associated with a release of radioactive substances (RaS) has been in the focus of interest of emergency preparedness and radiation protection specialists, as well as experts dealing with the dispersion of harmful substances in the atmosphere. Suitable tools for these analyses are applications of mathematical and physical models and simulation of this attack under 'realistic' conditions. The work presented here summarises the results of four tests, in which a RaS (a Tc-99 m solution) was dispersed over a free area with the use of an industrial explosive. Detection methods and techniques employed in these tests are described and values characterising the RaS dispersion--dose rates, surface activities in horizontal and vertical directions, volume activities, their space and time distributions and mass concentrations of aerosols produced after the explosion are presented and compared. These data will be applied to a comparison of outcomes of models used for the assessment of radiation accidents as well as in future field tests carried out under conditions of more complex geometry (indoor environment, terrain obstacles, etc.).

An evaluation of the response of a scintillation detector for estimating the radionuclide composition of a contaminated cloud.

We have made Monte Carlo calculations of the scintillation spectrometer response for the photon field from a cloud of contaminated air after selected scenarios of a nuclear power plant accident. Calculations (using MCNP5 code-X-5 Monte Carlo Team, 2005) were performed for 36 main energy lines of the expected radionuclides. The evaluated spectra enable us to simulate real composite spectra and their evolution in time, and to assess the applicability of a specific spectrometry system for a semi-qualitative and semi-quantitative analysis of the composition of the cloud.

Radon in context of natural radiation exposure: the Czech experience.

Radon issue should be seen in the context of other human exposures and harms. The range of doses from the internal (inhalation and ingestion) and external exposure pathways is presented. Indoor radon regulation is compared with regulation of other natural exposures.

Radon programme: presence and future.

An overview of radon programme experience is presented. The paper summarises broad topics concerning radon issue: philosophy of radon policy, radon measurements strategies with respect to indoor radon variation, progress in radon measurement of an individual house (radon diagnosis), national programmes, the role of preventive measures and interventions with respect to existing and future exposure and knowledge of radon risk, problems of remediation strategies, radon mapping process and sense of delineation of radon prone areas, public awareness on radon issue and publicity campaign. Some research activities are proposed aiming at effective solutions for radon issues in the future.

The weekly measurement deviations of indoor radon concentration from the annual arithmetic mean.

The difference between weekly measurements and the annual arithmetic mean of radon indoor concentration CRn,Indoor was studied in the Czech Republic. The deviations were analysed for 1537 weekly measurements which were consecutively obtained in 29 rooms over a period of 1 year and the annual arithmetic mean was calculated for each particular room. The relationship of the deviations to three meteorological parameters (i.e. outside temperature, atmospheric pressure, and weekly rainfall) and to the sequential number of a calendar week was studied. The effect of atmospheric pressure and weekly rainfall was not significant. The deviation between a weekly measurement and the annual arithmetic mean depended significantly on outside weekly average temperatures. If the average outside weekly temperature was below 10 degrees C, the radon concentration was systematically higher than that of the annual arithmetic mean. The deviation variability was lower up to a temperature of 10 degrees C. If the weekly average outdoor temperature was higher than 10 degrees C, the uncertainty of a weekly measurement of radon concentration was also higher.

Radon exposure and lung cancer risk--Czech cohort study on residential radon.

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of men employed underground in mines where exposures are relatively high in comparison to indoor exposure. Nevertheless, direct evidence of risk from residential radon is desirable. In 1990, a study was started comprising 12,000 inhabitants of an area with elevated radon concentrations. The mean level in the houses was higher than general mean of the country by a factor of five. In the period 1961-1995, a total of 173 lung cancers were observed. Comparing to nationally expected numbers (E), the observed number (O) of cases is elevated (O/E = 1.11), in contrast to generally low figures for cancers other than lung (O/E = 0.85). Lung cancer risk related to cumulative exposures experienced in the past 5-24 or 5-35 years were both significant. In relation to standard radon progeny concentration 100 Bq/m3, the excess relative risk coefficient was 0.103 (95% CI, 0.039-0.168), the value somewhat lower than findings in other indoor studies.

Applicability of various insulating materials for radon barriers.

The effectiveness of various insulating materials for limiting radon entry into houses has been investigated under laboratory conditions. Results for the radon diffusion coefficient measurements in more than 80 insulating materials are summarized. We have discovered that great differences exist in diffusion properties, because the diffusion coefficient varies within four orders from 10(-13) m2/s to 10(-10) m2/s. A methodological approach is proposed in order to identify the minimal thickness of radon-proof membranes, depending on building and soil characteristics. General guidelines for the selection of radon-proof insulation are presented.

Laparoscopic-assisted vaginal hysterectomy: American Association of Gynecologic Laparoscopists' 1995 membership survey.

A questionnaire was mailed to all members of the AAGL to determine the current performance of laparoscopic-assisted vaginal hysterectomy (LAVH), and to assess the relative frequencies of techniques and complications. Answers of the 1092 members who responded were entered into a database computer program and analyzed. The analysis revealed 14,911 LAVHs performed by 767 members. Complication rates appeared to be in the same range as those reported for vaginal hysterectomy and total abdominal hysterectomy. Inferior epigastric injury was the most common complication. Physicians showed a shift in their practices away from abdominal hysterectomy after they learned LAVH.

Cervical cancer screening in Bali: a public health issue.

Cervical cancer is the most common cancer in women in developing countries. Regarding cervical cancer in Bali, we sought to determine the incidence, to evaluate existing preventive and screening programs, to identify the population being screened, and to examine the methods of testing. The records of the Udayana Teaching Hospital pathology laboratory and Cancer Registry were reviewed, retrospectively. The incidence of cervical cancer in Bali is 7/100,000. There has already been a substantial increase in the number of Papanicolaou tests (PT) from 767 in 1990 to 1,355 in 1992. In 63% of these tests the results were Class II, indicating a need for attention to infection. Cervical intraepithelial neoplasia has a statistically significant increase with age. The number of PT performed peaks in the 35-44 year age group, with a sharp decline thereafter. Fifty-four percent of PT are performed in the capital city, which has only 20% of the female population. Bali Hindu women make up 94% of the female population, but receive only 81% of PT, while Muslim women make up 5% of the population and receive 12% of PT. Seventy-eight percent of PT contain no endocervical cells. There has already been a promising increase in the number of PT performed in Bali. Public health promotion efforts as well as outreach programs should be expanded, perhaps using the Banjar system, to reach older and rural women. Collectors of Pap smears should be instructed on the importance of endocervical sampling.