Published online by Cambridge University Press: 21 February 2011
A test method based on partial leachant exchange at constant intervals until leachate concentrations become stabilized has been used to obtain a data-base in evaluating long-term leaching patterns. Applied to basalt and granite specimens and compared with ground-water analyses, correlations which can be used in long-term leachability extrapolations have been established. They are based on the following principles: (i) Control of solubilities of major components by combined aluminosilicate species; (ii) Continued increase in levels of soluble species, e.g. Na+ and Cl−, with time; (iii) Initial rapid leaching of SO42−, along with Ca2+ and K+, followed by slowing down, probably due to the presence of selectively leachable phases; (iv) Initial retardation of Mg and Fe leaching followed by regrowth as sorption sites become saturated.