Fig. 1. Variable surface charge of three organic soils from Sudbury (SUD 12), Rouyn-Noranda (RN 7), and Valleyfield (VAL 4) (: measured by the back-titration; solid line: predicted by the non-ideal competitive adsorption [NICA]–Donnan model).
: measured by the back-titration; solid line: predicted by the non-ideal competitive adsorption [NICA]–Donnan model).