Radiological consequences of amending soils with bauxite residue gypsum mixtures

Abstract

This paper reports on the gamma (�) radiation flux from sandy soils of the Swan Coastal Plain treated with bauxite residue/gypsum at various application rates and assesses the radiological significance of soil amendment in relation to currently accepted standards. Amendment rates of up to 2000 t ha-1 of bauxite residue were used. There is a linear increase of incremental � dose with increasing rate of residue. The 1 mSv limit for incremental � dose exposure for the general public is reached for 100% occupancy at an amendment rate of 1500 t ha-1 of bauxite residue. The gamma rate of approximately 0.15 �Gy h-1 is similar to that for soils of much of the area between Bunbury and Capel in the south-west of Western Australia and is significantly lower than levels for Minninup beach where there are deposits of mineral sands.