FUNGAL ACTIVITY IN REDUCTION OF THE URANIUM CONTENT AND THE ACTIVITY CONCENTRATION OF OTHER RADIONUCLIDES IN SOME TENORM

The granitic tailing (GW) and the phosphogypsum (PG), solid wastes resulted from the leaching process
of the U-bearing granite and manufacturing of the phosphoric acid from the phosphate rocks respectively,
are considered as TENORM. Both of them retain considerable uranium concentration in addition to most
of the original radium content as well as other radionuclides. Due to their enhanced radionuclide contents
and their huge produced quantities, these wastes represent a real risk on man and the environment. The
present work employed the fungal activity to reduce the uranium content and radium activity concentration
in these radioactive solid wastes. Strain of the Aspergillus terreus (A. terreus) was isolated from the tested
TENORM and was propagated on the appropriate Dox liquid media. Four controlling factors affecting
the fungus leaching capability were investigated; the incubation period, solid/liquid ratio, incubation
temperature and the initial pH where their optimum values were recorded as three days, 1%, 30 oC and 4
respectively. Testing of the optimum conditions together on the solid wastes revealed that the A. terreus
reduced 66.9% and 62.5% of the uranium content in both the GW and PG wastes respectively. In parallel,
the A. terreus removed 76.5% and 63% of the radium activity concentration in the GW and PG wastes.