THE RA-226 BA-RATIO AS INDICATOR FOR PHOSPHOGYPSUM CONTRIBUTIONS TO RA-226 LEVELS IN SEDIMENTS/

Phosphogypsum discharges by phosphate-ore processing industries pollut e sediments of the Rotterdam harbour area with Ra-226. Direct measurem ent of this radionuclide in sediments does not provide a reliable indi cation of the elevation of the levels, since Ra-226 levels in sediment s depend on the particle size. To eliminate the size effect, the Ra-22 6/Ba ratio in sediments was tested as a possible indicator for the Ra- 226 in the discharges. The results indicate almost a doubling of the R a-226 levels in sediment samples due to phosphogypsum discharges. The contribution of phosphogypsum to the sediment mass was calculated in t he order of a few percent equivalent.