The future of activation analysis: A case study of solid waste leachability

In the light of the remarkable strides in radioactivation analysis methods and techniques that haved been achieved progressively in the 34 years since Modem Trends conferences began, some speculations on the future directions that the field might take in the foresceable future seem appropriate at MTAA-9. Together with improvements that will likely occur in instrumentation, in prompt and ion-beam methods, there would seem to be yet a further potential for extending the range of information that radioanalytical techniques can provide by complementing RAA measurements on samples with an increased use of manipulative chemistry. Among complementary chemical methods are not only pre-activation chemistry for speciation studies and matrix removal but also, radiotracer/INAA combinations, isotopic exchange/INAA (as illustrated in this paper through recent studies on the behavior in the environment of solid waste residues), substoichiometric-RAA and classical radiochemical, post-activation separations for specific element(s). Results are presented on the toxic element content of solid waste ashes by INAA and on their uptake of65Zn and109Cd in which there is evidence of two interaction processes between waste particles and simulated groundwater: a rapid exchange (within a few minutes) and slow exchange extending over days. This tends to confirm results on leachability of toxic elements from solid wastes but serves to distinguish adsorption processes from isotopic exchange.