Modelling and mitigating dose to firefighters from inhalation of radionuclides in wildland fire smoke

Abstract

Firefighters responding to wildland fires where surface litter and vegetation contain radiological contamination will receive a radiological dose by inhaling resuspended radioactive material in the smoke. This may increase their lifetime risk of contracting certain types of cancer. Using published data, we modelled hypothetical radionuclide emissions, dispersion and dose for 70th and 97th percentile environmental conditions and for average and high fuel loads at the Savannah River Site. We predicted downwind concentration and potential dose to firefighters for radionuclides of interest (137Cs, 238Pu, 90Sr and 210Po). Predicted concentrations exceeded dose guidelines in the base case scenario emissions of 1.0 × 107 Bq ha–1 for 238Pu at 70th percentile environmental conditions and average fuel load levels for both 4- and 14-h shifts. Under 97th percentile environmental conditions and high fuel loads, dose guidelines were exceeded for several reported cases for 90Sr, 238Pu and 210Po. The potential for exceeding dose guidelines was mitigated by including plume rise (>2 m s–1) or moving a small distance from the fire owing to large concentration gradients near the edge of the fire. This approach can quickly estimate potential dose from airborne radionuclides in wildland fire and assist decision-making to reduce firefighter exposure.

Cesium emissions from laboratory fires

“…Wildfires have the potential to be a significant source of secondary contamination and exposure during and following the initial response. A large wildfire may generate large amounts of radioactive materials suspended in the atmosphere to cause exposure risk to firefighters and the nearby public and contaminate or recontaminate wide areas by atmospheric dispersion (Kashparov et al 2000;Hohl et al 2012;Evangeliou et al 2014;Viner et al 2015;Goldammer, Statheropoulos, and Andreae 2009;Goldammer et al 2017). Inhalation of even small amounts of radioactive material has the potential to raise the risk of developing cancer later in life.…”

4th Symposium on Occupational Safety and Health Proceedings Book

“…However, the measurement in real-time in a forest fire proves to have great difficulty in the application of equipment and the innovation of the process of sampling. In this way, some ways of assessing radioactivity are known through the use of autonomous large-volume samplers, portable aerosol samplers (Carvalho et al, 2014), by estimating the effective dose by inhalation using the Gaussian model (Viner et al, 2015) or through the use of other models. These authors use the Linear No-Threshold model to assess the risk to human health of a forest fire in a forest with radiological contamination.…”

Predicted cumulative dose to firefighters and the offsite public from natural and anthropogenic radionuclides in smoke from wildland fires at the Savannah River Site, South Carolina USA

“…When radionuclides are considered individually, the concentration thresholds for a dose that exceeds the established worker limits are uncommon except for extreme values observed in wildland fuels contaminated in nuclear incidents (Viner et al 2015). To date, no assessment has been made of cumulative dose to firefighters or to the public from natural radionuclides in conjunction with anthropogenic radionuclides from wildfires.…”

“…A method was recently developed to model emission, exposure, and dose to firefighters for any individual radionuclide during fires knowing only certain basic terms like fuel load and consumption, fire spread, the properties of the radionuclides, and their concentrations in the fuel (Viner et al 2015). These components can then be coupled to a firefighter's physical location on the fire line, breathing rate, and shift length.…”

“…The potential dose to a firefighter or a member of the public is a consequence of the cumulative dose from all radionuclides released during a fire, which can be calculated using this method. However, worldwide measurements contain very few observations of more than one radionuclide in wildland fuels either man-made or natural (Hejl et al 2013, Viner et al 2015. No published observations exist of a complement of manmade and dominant natural radionuclides in wildland fuels from which cumulative dose can be estimated.…”