The synthesis and characterization of poly (ethylenediaminetetraacetic acid-co-lactose) of high molar mass (132 kg mol(-1)) is described. The polycondensate with pendant carboxylic groups was shown to be hydrolytically and microbiologically degradable by using conventional microbiological methods. The metal complexing properties of the polyester were studied for Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sr(II), Cd(II), Pb(II), and Al(III) ions in aqueous solution using the liquid-phase polymer-based retention (LPR) method. In addition, the complexing capacity of the Cu(II)-saturated copolymer was determined by TGA to be 182 mg g(-1) polymer. According to the retention profiles determined as a function of filtration factor by using LPR in conjunction with inductively coupled plasma spectrometry, Cr(III) and Fe(III) showed a strong interaction with this polymer under these conditions, indicated by retention values of 100% at pH 5. (c) 2006 Wiley Periodicals, Inc.