Fig. 1. Cadmium (a) and copper (b) concentrations, corrected for mixing, in the percolate collected from different standard-size suction cups at pH 4.5. For the conditions at Steps 1 to 4 of the experiment refer to the Materials and Methods section and Table 3. Volumes are given in multiples of the pore volume (V₀) of the respective cup. The reference lines show the expected metal concentrations if no interaction with the cup materials occurred (i.e., the concentration measured in the initial solution).