On the use of retrospective dosimetry to assist in the radiological triage of mass casualties exposed to ionising radiation.

The reconstruction of the Cochabamba (Bolivia) radiological incident (IAEA-International Atomic Energy Agency 2004 The Radiological Accident in Cochabamba STI/PUB/1199 (Vienna: IAEA)) was used to assess and evaluate retrospective dosimetry methodologies. For this purpose an unshielded radioactive source was placed inside a transportation vehicle (bus) resembling a radiological exposure device. External doses were assessed using water and anthropomorphic phantoms that were placed at various positions in the vehicle and equipped with both fortuitous dosimeters (chip cards, mobile phones), individual dosimeters (electronic dosimeters, thermoluminescent and optically stimulated luminescence dosimeters) and in three cases also with blood sample tubes in thermos flasks for cytogenetic methods. This paper gives a detailed description of the experimental setup, the results of the reference dosimetry, including organ dose assessment for the phantom closest to the source, and includes a compilation of the main results obtained by the retrospective dosimetry techniques. Comparison is made to the results of dose reconstruction obtained by IAEA during the response to the Cochabamba incident in 2002.

Guidelines for first responders based on results from deploying a mockup radiological dispersal device.

During the past 7th Security Framework Program the European Commission funded a research project called CATO (CBRN Crisis management, Architectures, Technologies and Operational procedures) to develop a prototype decision support system for crisis management in addition to providing a suite of guidelines for first responders and incident commanders when dealing with chemical, biological, radiological or nuclear incidents. In order to derive these guidelines a proof-of-concept experiment was setup during which several passive agent (Stable CsCl) dispersions with improvised explosive devices and vehicle-borne improvised explosive devices were carried out. Each dispersion was thoroughly characterised by a number of monitoring devices, including high-volume air samplers and size-segregated air samplers. All environmental and forensic samples were collected by the UK counter terrorism police, following strict labelling and chain-of-custody protocols. The samples were analysed at the Belgian Nuclear Research Center suing the k0 method for instrumental neutron activation technique. A full consequence assessment analysis was carried out assuming that the observed concentration of Cs-133 in samples was Cs-137 instead and use was made of the specific activity of Cs-137. Due to the sensitivity of the information the European Commission classified this research. The resulted reported on in this work have been unclassified and are released to assist emergency planners and first responders to take the necessary precautions. The results indicate that, up to distances of 50 m from ground zero radiation levels will be considerable and therefore live-saving actions must be performed by fire/rescue wearing full protective gear. In addition, low-wind conditions will favor a long airborne residence time and therefore the use of full-face protective gear is a must. In order to protect first responders, a radiation protection specialist is to determine how long people can enter and remain in the contaminated area. The recovery of evidence in the case of a car-bomb will be hard or even impossible due to the high level of radioactive material remaining inside the vehicle.

Effective and ecological half-lives of 137Cs in cow's milk in alpine agriculture.

In the mountainous "Hohe Tauern" region of Salzburg (Austria), milk samples have been collected in a long-term montitoring programme since 1988, at eight alpine sites used for extensive, seasonal stock farming. For this alpine environment with its acidic soils developed on silicate bedrock, high soil-to-plant transfer factors and long-lasting (137)Cs contamination levels in milk--the main product of seasonal agriculture at elevated altitudes--are characteristic features. The decrease in (137)Cs concentration in milk measured since 1988 turned out to be best described by one or two effective half-lives. For the period from 1993 to 2007, which can be modelled with one effective half-life for all sites, effective half-lives between 3.7 and 15.0 years (ecological half-lives: 4.3-29.9 years) were obtained. The effective half-life increases with mean altitude of the investigated graze pastures, probably due to reduced migration velocities of (137)Cs and low (137)Cs half-value depths of a few centimetres in the soil.

Reactive oxygen species, especially O2+* in cancer mechanisms.

UNLABELLED: In the nature including the human organism there are 5 reactive oxygen species (ROS): O2, O2-*, O2+*, 1O2, O3 with different electromagnetic characteristics and biological effects. The effects of enrichment of medical oxygen O2 with traces of ROS on various cells were tested in experiments. METHODS: Human embryonic lung fibroblasts WI38 damaged by Radon Rn222 into WI38/ Rn cells and WI38 cells transformed by virus SV40 into VA13 cells were exposed to different ROS gas mixtures, prepared in high - voltage plasma chamber of "Oxygen Ion 3000". Trans-membrane resting potential (TMRP) was measured and cells morphology was visually observed using microscopy during 10 days. RESULTS: Exposition of WI38, WI38/Rn and VA13 to medical O2, alone show no effect in TMRP and in cell morphology. But pico-concentration of O2+* in medical O2 increased the TMRP in WI38/Rn cells from -25mV to -35mV (variance 0.5-2mV) (p < 0.001) with improvement of cells morphology and the TMRP of VA13 cells from -15mV to -32mV (2-3mV) (p < 0.001) with a maximum effect on the 5th day. Later the TMRP strongly decreased and the cell membrane ruptured due to water influx. O2, enriched with O2-* alone or together with O2+* had no significant effect in WI38/Rn and VA13 groups (p > 0.05). CONCLUSION: Radon protective effect on WI38/Rn or destructive effect on VA13 of pico-concentrations of O2+* in medical O2 conforms to the theory of hormesis resp. to hypothesis of cancer induction mechanisms, supporting it's further experimental or clinical use.

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.