Similar patterns were found in the other 17 experiments. The relation between the soil pH
and normalized concentration is in focus in thiswork, and the results from all 18 experiments
are summarized in Fig. 3, where data points for the slices (pH, normalized concentration)
are given.
Two of the experimental soils, 2 and 3, were polluted with all three heavy metals of this
investigation: Cu, Zn and Pb. In Fig. 3, the data points for these two soils are shown with
white symbols. The pH below which all data points for these soils show more that 50%