Application of a liquid scintillation technique to the measurement of 226Ra and 224Ra in samples affected by non-nuclear industry wastes

Experimental procedures have been developed for the determination of Ra-226 and Ra-224 activity concentration in solid and liquid samples collected around a non-nuclear industrial area by liquid scintillation counting. The different radiochemical procedures developed in this work have been adaptations of a radiochemical procedure previously used, for Ra-226 and Ra-224 determinations by LSC in drinking water, which was improved, refined up and adapted to the type of sample to be applied. These improved radiochemical methods have been applied to waste samples (phosphogypsum) produced by two factories which are engaged in phosphoric acid production, and to waters collected from the Odiel river, where during the sampling period a fraction of these wastes were released. Ra-226 activity concentrations in the phosphogypsum ranged from 673 to 1178 Bq/kg dry weight, indicating that the wastes are particularly enriched in this radionuclide. Consequently, high Ra-226 levels were easily found in the river waters analysed, especially in the neighbouring zones of the waste discharges.