Fig. 4

Gibbs plot for anion and cation (a) cations (spatial dynamics), (b) anions (spatial dynamics), (c) cations (seasonal dynamics), (d) anion (seasonal dynamics) (note: 34 samples for spatial variations and seasonal variations (N = 39 for pre-monsoon, 40 each for monsoon and post-monsoon; the variables are explained in Sect “Methodology”).