CS-137 AND RA-226 DETERMINATION IN SOIL AND LAND SNAILS FROM A RADIOACTIVE-WASTE SITE

Environmental radioactivity studies related to nuclear facilities can provide information concerning the transfer of radionuclides to the su rrounding soils, water and the local biota. A study of Ra-226, Cs-137 and K-40 content in soils and in land snails, Helix aspersa Muller, ha s been performed at the confined Storage Centre for Radioactive Waste (Maquixco, Mexico). At this site, solid and liquid radioactive waste h as been stored for two decades; tailing piles of radiometric ore also stood for some time before being buried in specific containers. The nu clear technique used was gamma spectrometry. Atomic absorption spectro photometry was used for soil and land snails chemical analysis. The pr eliminary results obtained in soil samples show Ra-226 and Cs-137 valu es ranging from 88 to 19 979 and from 89 to 4961 Bq/kg (dry wt.), resp ectively, depending on the sampling region. For the snails, Ra-226 lev els in shell samples up to a factor of 9 greater were obtained for the site samples as compared with reference samples collected 100 ion awa y. The results are discussed as a function of the uranium ore tailings localization at the site; a preliminary estimation of concentration f actors (soil/snail) is also intended.