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

More than 10,000 whole organism concentration ratio (CRwo-water) values for freshwater wildlife were derived from radionuclide and stable element data representing an Australian tropical U mining environment. The CRwo-water values were summarised into five wildlife groups (bird, fish, mollusc, reptile and vascular plant). The summarised CRwo-water values represented 77 organism-element combinations. The CRwo-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.