The very pronounced selectivity of pectinates, especially their potassium-forms, for copper(II), lead(II), barium, cobalt(II), calcium, and strontium ions (log K = 1.60 – 0.85) was established and was presumably due to the presence in the pectin of deacetylated hydroxyls and the greater radii of the bound metal cations. The ion-exchange efficiency of magnesium and calcium polyhyaluronates for strontium, barium, copper(II), and potassium was slightly less (log K 0.91 – 1.18) although it still surpassed the analogous ability of calcium and sodium alginates for copper(II), lead(II), cadmium, strontium, and barium ions (log K 0.45 – 1.05). The polyhyaluronates typically had the lowest selectivity.