The, synthesis of the first lactose main-chain copolymer was achieved by means of solution poly-reaction of ethylenediaminetetraacetic acid dianhydride with D-lactose. The water-soluble carboxy-functional material based on EDTA with a high molar mass is shown to be biodegradable. The metal complexing properties of the polymer based on the liquid-phase polymer-based retention (LPR) method showed a strong interaction with Cr(III), Fe(III), and Sr (II) ions.