Poly(2-hydroxyethyl methacrylate/itaconic acid) [P(HEMA/IA)] hydrogels were prepared by the gamma-ray irradiation of aqueous solutions. In the presence of lead and cadmium ions, the UO22+ ion uptake on P(HEMA/IA) hydrogels was investigated with two types of hydrogel systems prepared by nonprestructuring and prestructuring methods. A differential pulse polarographic technique was used for the determination of trace quantities of uptake elements by the measurement of the reduction peak currents at -200, -410, and -580 mV for UO22+, Pb(II), and Cd(II) ions, respectively. Hydrogels prestructured with UO22+ ions took up approximately 45% more UO22+ ions than hydrogels prepared by the usual procedure. The UO22+ ion uptake capacity of the hydrogels increased with an increasing percentage of itaconic acid in the hydrogel systems and an increasing concentration of UO22+ ions in the presence of Pb(II) and Cd(II) ions. Uptake studies showed that other stimuli, such as the temperature and ionic strength of the solutions, also influenced the UO22+ ion uptake capacity of the P(HEMA/IA) hydrogels. (C) 2003 Wiley Periodicals, Inc.