Friedrich Steinhausler

Dose calculations for the respiratory tract from inhaled natural radioactive nuclides as a function of age--I. Compartmental deposition, retention and resulting dose.

Abstract The deposition and retention models and the anatomical and physiological data as proposed by the ICRP Task Groups on Lung Dynamics and Reference Man are valid only for adult dosimetry. However, the change of the growing organism causes an age-dependent variation of the radiation burden to the respiratory tract. Therefore, age-dependent functions of anatomical and physiological parameters were defined. For this purpose data were either interpolated from literature or calculated from theoretical modeling. With these functions and defined aerosol composition, age-dependent deposition probabilities in the single regions of the respiratory tract were determined. For the demonstration of lung dosimetry as a function of age the naturally occurring radon daughters were used as an example. By applying typical mean nuclide concentrations found in the atmosphere of an urban environment and defined age-dependent daily life patterns, the annual inhaled amount of radioactivity was computed. With the above data, dose calculations for the single ICRP lung model compartments were performed. This revealed that the inhaled dose in both the tracheobronchial and pulmonary regions showed a strong dependence on age; a pronounced maximum value was reached at the age of about 6 yr for radon and thoron decay products.

Chernobyl And GoiÂnia Lessons For Responding To Radiological Terrorism

The deployment of a radiological dispersal device (RDD) is likely to result in relatively low radiation exposure of the targeted population, insufficient to cause a severe radiation detriment. Nevertheless, due to atmospheric dispersion of the radioactive material, an urban area equaling several city blocks could be affected. The current knowledge base concerning the response to radiological terrorism, focusing mainly on environmental cleanup and site recovery (CSR) of areas with radioactive contamination due to the deployment of an RDD, is largely derived from military scientific tests or exercises assembled over the past 50 y with only limited applicability to the consequences of an RDD detonating in a city. This paper focuses on the extensive experience in CSR gained in the management of the radiological accident contaminating the Brazilian city of Goiânia in 1987, and managing the aftermath of the Chernobyl reactor accident in 1986. The incident in Goiânia demonstrated the numerous practical difficulties of implementing a sound CSR, based on a balanced judgment of all relevant factors, such as radiation safety, environmental issues, economic consequences, and public fear. A review of the different stages of the intervention policy in the former Soviet Union reveals that risk-benefit cost analysis was not used for the decision-making process during the later stages of the post-accident situation. Instead, a CSR policy was adopted that resulted in continuously escalating costs. The results of this analysis are used to develop an Integrated Cleanup and Site Restoration Concept and recommend practically applicable solutions from Lessons Learned. Language: enThe deployment of a radiological dispersal device (RDD) is likely to result in relatively low radiation exposure of the targeted population, insufficient to cause a severe radiation detriment. Nevertheless, due to atmospheric dispersion of the radioactive material, an urban area equaling several city blocks could be affected. The current knowledge base concerning the response to radiological terrorism, focusing mainly on environmental cleanup and site recovery (CSR) of areas with radioactive contamination due to the deployment of an RDD, is largely derived from military scientific tests or exercises assembled over the past 50 y with only limited applicability to the consequences of an RDD detonating in a city. This paper focuses on the extensive experience in CSR gained in the management of the radiological accident contaminating the Brazilian city of Goiânia in 1987, and managing the aftermath of the Chernobyl reactor accident in 1986. The incident in Goiânia demonstrated the numerous practical difficulties of implementing a sound CSR, based on a balanced judgment of all relevant factors, such as radiation safety, environmental issues, economic consequences, and public fear. A review of the different stages of the intervention policy in the former Soviet Union reveals that risk-benefit cost analysis was not used for the decision-making process during the later stages of the post-accident situation. Instead, a CSR policy was adopted that resulted in continuously escalating costs. The results of this analysis are used to develop an Integrated Cleanup and Site Restoration Concept and recommend practically applicable solutions from Lessons Learned.

90Sr and 137Cs in environmental samples from dolon near the semipalatinsk nuclear test site

The (90)Sr and (137)Cs activities of soil, plant, and milk samples from the village of Dolon, located close to the Semipalatinsk Nuclear Test Site in Kazakhstan, were determined. The areal deposition at the nine sampling sites is in the range of <500 to 6,100 Bq m(-2) and 300 to 7,900 Bq m-2 for (90)Sr and (137)Cs, respectively. Similar values have been reported in the literature. At some of the sites both nuclides mainly have remained in the top 6 cm of the soil profiles; at others they were partly transported into deeper soil layers since the deposition. For most of the samples the (90)Sr yield after destruction of the soil matrix is significantly higher than after extracting with 6 M HCl indicating that (90)Sr is partly associated with fused silicates. The low mean (90)Sr activity concentrations of vegetation samples (14 Bq kg(-1) dw) and milk samples (0.05 Bq kg(-1) fw) suggest that this has favorable consequences in terms of limiting its bioavailability.

Fallout strontium and caesium transfer from vegetation to cow milk at two lowland and two Alpine pastures.

Vegetation-to-milk transfer coefficients for 137Cs, 90Sr and stable strontium were determined for cows grazing on two intensively managed lowland pastures and two Alpine pastures in Austria. The 90Sr transfer coefficient at the four pastures ranged from 0.0005 to 0.0012 dl-1 and correlated with the stable strontium transfer coefficient (0.0006-0.0013 dl-1) with the lower values found on the intensively managed pastures. The 137Cs transfer coefficient ranged from 0.0009-0.0045 dl-1.

Radiation exposure of the respiratory tract and associated carcinogenic risk due to inhaled radon daughters.

The atmospheric content of radon and its decay products contributes significantly to the radiation exposure of man even in the normal environment. In this study, the risk for lung cancer induction associated with normal exposure to natural radionuclides is assessed in Salzburg, Austria. Altogether more than a thousand rooms have been investigated by using combined radon grab-sampling methods together with continuous measurements of radon and daughters at different control stations. Dose calculations were carried out for 729 demoscopically selected test persons, considering individual differences in age, sex and life-style and atmospheric nuclide concentrations at different sites. Using a specially developed age-dependent lung model, the dose frequency distribution of the absorbed dose to the basal cells of the bronchial epithelium could be evaluated for the population of Salzburg. Dose modifications caused by anatomical and physiological variabilities as well as microdosimetric considerations of the stochastic events during energy deposition result in a significantly increased dispersion of the dose histogram. Induction of lung cancer due to inhalation of radon and decay products can be correlated with cumulative exposure based on experience with lung cancer incidence amongst uranium miners. Using the recommended range of lifetime risk values of 20-45 X 10(-5)/WLM (UN77), it is shown for Salzburg that about 15% of the observed number of lung cancer cases may be induced by natural radionuclides.

Occupational exposure to radon in treatment facilities of the radon-spa Badgastein, Austria

In the spa Badgastein, Austria, radon is used for therapeutic purposes for various diseases. Radon inhalation is applied in a thermal gallery with atmospheric radon concentrations up to 100 kBq/m3, elevated temperature up to 41°C, and humidity close to 100%, or in the form of radon baths where Rn is emanated from water with high natural Rn activity. Frequently, a combination of both treatment procedures is applied. The high environmental radon concentration levels in the thermal gallery, and in the various radon baths, can result in elevated radiation exposure levels, subject to significant local and temporal changes. Particularly in Rn-baths, the treatment procedures can result in high Rn levels or peaks during the use and replacement of Rn-water. For the assessment of the occupational exposure, a combination of long- and intermediate-term integrating Rn-measurements and continuous Rn and Rn-progeny measurements was used to investigate six different treatment facilities. Long-term integrating Rn-measurements, over a period of 1–13 months, provide reliable average Rn-concentration. However, these values cannot be used directly for the dose calculation of individuals due to the short-term fluctuation of the radiation exposure. Parallel integrating and continuous Rn-measurements and continuous Rn-daughter measurements were made to calculate personal occupancy weighting factors and Rn-equilibrium factors to determine potential alpha energy concentration exposure of daytime personnel.

What It Takes to Become a Nuclear Terrorist

There is justified concern that terrorists may use nuclear or other radioactive material to commit an act of terrorism. However, there are multiple barriers to be overcome by a terrorist to actually be able to deploy such a weapon. This article discusses four threat scenarios involving nuclear and other radioactive materials: radioactive dispersion with criminal intent, radiological malevolence, attack on a nuclear power plant, and nuclear weapons. Altogether, 16 attack modes are identified with largely different logistical and technical requirements for their implementation. However, none of them should be considered as out of realm for a dedicated terror organization with a certain degree of sophistication.

The Austrian Radon Project

Abstract The aim of the Austrian Radon Project (ARP) is to investigate the 222Rn concentration in 0.3-0.5% of all Austrian dwellings to identify areas with elevated radon exposure. The survey is carried out using short-term and long-term integrating radon detectors covering a population of 2 800 000 persons so far. The homes were randomly selected from the telephone directory. The radon concentration distribution showed a log-normal shape. County-means between 60 and 330 Bq/m3 were found. A radon potential was introduced to deduce a geological risk from the data taken under different circumstances in different types of houses. This radon potential was defined as the annual mean radon concentration in a standard dwelling and is computed by normalizing the measured radon data to this standard dwelling.

IAEA/EPA international climatic test program for integrating radon detectors

As an element of the joint IAEA-EPA International Radon Metrology Evaluation Program, a climatic test of long-term integrating radon detectors was conducted at the U.S. EPA Radiation and Indoor Environments National Laboratory. The objective of this study was to test the performance of commonly used commercially available long-term 222Rn detector systems under extreme climatological conditions using filtered polycarbonate CR-39 plastic analyzed by the manufacturer using the track-etch method, unfiltered LR-115 film analyzed by the manufacturer, and Teflon based electrets analyzed in the field by EPA using the manufacturers equipment. The EPA environmental radon chambers were used to expose detectors to extreme cold and dry (less than 4.0 degrees C air temperature and 25% relative humidity) and hot and humid (greater than 35 degrees C air temperature and 85% relative humidity) climatic conditions. During phase I detectors were exposed to low temperatures and low humidities, and during phase II detectors were exposed to high temperatures and high humidities. Typical indoor equilibrium fractions (near 50%) and radon concentrations of about 150 Bq m(-3) were maintained for each phase, which lasted 90 d. The results indicated that the optimal detector for extreme climatic conditions is dependent on the relative importance of bias and precision. Overall, however, the filtered track-etch type detector produced the most reliable results under the extreme conditions.

Elevated indoor exposure in Chinese carbon brick and cave dwellings.

In two rural provinces of China residents are exposed to significantly elevated levels of natural radiation: in Gansu Province millions of people have been living in earth-dug cave dwellings for several generations; in Jiangxi Province several hundred thousand inhabitants reside in carbon-brick dwellings, containing elevated levels of 238U and 226Ra. In a pilot study regional lung cancer mortality rates were investigated in the affected areas and were found to be higher than for control groups in normal dwellings in the same area.