A sequential extraction scheme to ascertain the role of organic matter in radionuclide retention in Mediterranean soils

A sequential extraction scheme which indicates the role of organic matter in radionuclide retention was applied to two types of Mediterranean soil (sandy-loam and sandy), with low percentages of organic matter and with different contents of clay mineral, which had been previously contaminated with a radioactive aerosol, containing⁸⁵Sr,¹³⁴Cs and^110mAg. Different distributions were obtained for the three radionuclides, depending on the type of soil.⁸⁵Sr was the most available radionuclide for both types of soil, showing significant binding to organic matter in sandy-loam soil.¹³⁴Cs was the most retained radionuclide: for low-organic-matter soils, its availability seemed to depend on clay mineral content.^110mAg associated with available organic sites showed a positive correlation with organic matter content.