Surface water transport of radionuclides

Background

Surface water transport of mine-origin radioactivity can occur either due to a controlled release from a working minesite (e.g. release of excess stored water) or uncontrolled release (e.g. erosion of material from a site, or surface expression of groundwater containing radionuclides). The radionuclides can then incorporate in traditional foodstuffs either from areas where mine origin material has deposited or directly from the water column (for mussels or fish), and thus contribute to the radiation dose received by the public.

Current research projects

Surface water transport of uranium in the Gulungul catchment

In January 2004 and in February 2006, samples taken for routine monitoring showed elevated concentrations of uranium at Gulungul Creek downstream (GCDS) compared to Gulungul Creek upstream (GCUS) and an investigation into the metal sources was deemed necessary. A mechanism was suggested in which the metals are leached from acid sulfate soils in the catchment at the start of the wet season, then accumulate and flush down into the creek under specific hydrological conditions. The elevated uranium concentration in 20006 for instance, coincided with the first period of significant overbank flow in Gulungul Creek.

Correlations between turbidity and suspended sediment concentration have been derived for gauging stations in the Gulungul Creek catchment by the HGP group of eriss. The project currently focusses on deriving a relationship between uranium (and other metal) concentrations and suspended sediment concentration in the creek.

Project leader:Peter Medley

Radio- and lead isotopes in sediments of the Alligator Rivers Region

This is a joint project with Charles Darwin University, funded through the ARC Linkage-Projects scheme. The objective of this project is to characterise sources and pathways of pollutants in catchments in the Alligator Rivers Region at Nabarlek mine, Ranger and natural analogues, and to develop a joint lead isotope/radionuclide approach for monitoring erosion from a (rehabilitated) uranium mine site and assessment of post-rehabilitation landform stability.

eriss Project leader: Dr Andreas Bollhöfer.

Some relevant publications

Frostick A, Bollhöfer A, Parry D, Munksgaard N, Evans K 2008. Radioactive and radiogenic isotopes in sediments from Cooper Creek, Western Arnhem Land. Journal of Environmental Radioactivity 99, 468-482.

Hancock G.R, Grabham M.K, Martin P., Evans K.G. and Bollhöfer A. (2006). An erosion and radionuclide assessment of the former Nabarlek uranium mine, Northern Territory, Australia. Science of the Total Environment 354, 103-119.

Sauerland C, Martin P & Humphrey C 2005. Radium 226 in Magela creek, northern Australia: Application of protection limits from radiation for humans and biota. Radioprotection, Suppl. 1, vol 40, S451-S456.

Bollhöfer A & Martin P (2003). Radioactive and radiogenic isotopes in Ngarradj (Swift Creek) sediments: a baseline study. Internal report 404, Supervising Scientist for the Alligator Rivers Region, Darwin.

Murray AS, Johnston A, Martin P, Hancock G, Marten R & Pfitzner J 1993. Transport of naturally occurring radionuclides by a seasonal tropical river, northern Australia. Journal of Hydrology 150, 19-39.

Wasson RJ (ed) 1992. Modern sedimentation and late quaternary evolution of the Magela Creek Plain. Research report 6, Supervising Scientist for the Alligator Rivers Region, AGPS, Canberra.