Inhalation Doses for Aboriginal People Reoccupying Former Nuclear Weapons Testing Ranges in South Australia

Abstract

The Australian Government plans to rehabilitate the former nuclear weapons testing ranges at Maralinga and Emu in South Australia and to allow access to the areas for the Pitjantjatjara (Aboriginal) people who are the traditional owners of the land. The major radiological hazard posed by reoccupation of the ranges arises from inhalation of residual plutonium. The committed effective dose that these people might receive from inhalation on reoccupation of the lands is computed for a range of sites. The estimated doses for permanent occupancy range up to 300 mSv y-1 indicating the need for substantial rehabilitation before these areas are suitable for unrestricted access.

Modeling the inhalation enhancement factor in prospective radiological risk assessment

“…For the conditions of heavy atmospheric aerosol loading, e.g., during mechanical soil disturbances or very strong winds, the particle size distribution tends to be bimodal, with a large particle component [5,[9][10][11]. This component is transient and residence times in air of large particulates, suspended as a result of mechanical soil disturbance, are only on the order of seconds due to gravitational settling [5].…”

Soil-Related Input Parameters for the Bioshere Model

“…These fractions had MAD of 5 to 6 µm and more than 11 µm (Johnston et al 1992 [DIRS 177227], p. 632).…”

“…Measurements of the enhancement factor in Southern Australia at the sites of British nuclear tests resulted in values typically greater than unity (Shinn 2003 [DIRS 177226], Table 2; Johnston et al 1992 [DIRS 177227], Table 4). …”

Studies of Plutonium Aerosol Resuspension at the Time of the Maralinga Cleanup

“…A considerable amount of research had been conducted at Maralinga by the Australian Radiation Laboratory, now the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), prior to the cleanup (Johnston et al, 1992, Williams 1993, Johnston et al 1993, Burns et al 1994, Burns et al 1995. ARPANSA staff made major contributions to delineate the areas with Pu in the soil, to determine the degree of secondary soil contamination by fission products from nuclear testing, to measure Pu resuspension by wind erosion of the undisturbed soil, and to prepare assessments of the human health risk from residual soil Pu.…”