Fig. 8. Concentration distributions of the tracers vs. depth. The total tracer concentration per volume of soil, _t, was horizontally averaged and normalized by the total mass of tracer recovered per unit area, m₀. Concentration distributions for sampling directly after application are shown for (a) Br^– and (b) Brilliant Blue (BB), as well as for sampling after 90 d for (c) Br^– and (d) Brilliant Blue. The data for Brilliant Blue represent averaged concentrations of 15 sampling locations corresponding to those where Br^– was sampled (local scale).