Investigations into the nature of the binding of ^110mAg, K, Ca, Al and Fe in soil

Eleven extraction procedures have been used to determine the chemical association of ^110mAg with the major phases of soil. The effectiveness of these extraction procedures have been further evaluated by determining the extractability of K, Ca, Al(III) and Fe(III). The ready extractability of ^110mAg(I) by diethyldithiocarbamic acid (DDC), a soft base complexing agent, indicates that it must be present in the soil as a complexed form from which Ag⁺ is readily released to diethyldithiocarbamic acid. In contrast to this ready extractability of ^110mAg⁺ by DDC, its extractability by another soft base complexing agent the thiacrown ether 1,5,9,13-tetrathia-cyclohexa-decane-3-11-diol (TTCD) is moderately low. The extractability of ^110mAg into dimethylformamide on in situ trimethylsilylation of soil implies that some of these binding sites must be on the humic matter of soil. The data indicate that K was held mainly in the silicate matrix whereas Ca appeared to be held on ion exchange sites of soil which are part of humic matter. Some Al(III) and Fe(III) appeared to be bound to the organic substances in soil.