At low redox conditions (Figure ), log S is always negative for all tested ions. This means that in waterlogged conditions PDMA primarily coordinates Zn II since there is minimal competition from other metal ions. Above pH 6 we observe an increasing selectivity of PDMA for Fe II but Zn II remains the dominant complex at all pHs (logS = -0.5). In contrast, in the aerobic system (Figure ) at pH < 6, the selectivity of PDMA for Cu II increases (log S = 4.65 at pH 3), whilst log S is ≤ 0 for Fe III , Fe II , Mn II and Mg II . Above pH 6 the selectivity of PDMA for Cu II decreases but it always remains above zero (logS = 0.22 at pH 7), whilst at pH > 9 the selectivity for Cu II and Fe III increased, with logS values of 0.85 and 0.31, respectively, highlighting the high competition of Cu II and Fe III against Zn II in alkaline pH.