Whole organism concentration ratios in freshwater wildlife from an Australian tropical U mining environment and the derivation of a water radiological quality guideline value

Abstract

More than 10,000 whole organism concentration ratio (CR_wo-water) values for freshwater wildlife were derived from radionuclide and stable element data representing an Australian tropical U mining environment. The CR_wo-water values were summarised into five wildlife groups (bird, fish, mollusc, reptile and vascular plant). The summarised CR_wo-water values represented 77 organism-element combinations. The CR_wo-water values for U decay series elements were used in a tier 3 ERICA assessment. The assessment results were used to derive a water radiological quality guideline value (GV) for radiation protection of freshwater ecosystems in the context of the planned remediation of the Ranger U mine. The GV was an above-background water ²²⁶Ra activity concentration of 14 mBq L^-1 (filtered fraction) or approximately 22 mBq L^-1 (total fraction). The GV was based on the results of mollusc-bivalve as the limiting organism for the freshwater ecosystem.

Keywords: Environmental exposure; Radionuclide transfer; Radium-226; Remediation; Tropical radioecology; Uranium mining.