The development of a voltammetric microsystem for monitoring and speciation studies of trace elements in natural waters is presented. This system was designed to provide an efficient coupling of the square-wave anodic stripping voltammetry (SWASV) detection with the permeation liquid membrane (PLM) technique. It consists of a voltammetric microcell, based on a gel-integrated Ir(Hg) microdisk array, a PLM and two micromachined channels for the sample and strip solutions respectively. The analytical performance of the microsystem was first assessed for Pb(II) and Cd(II) and then the simultaneous accumulation and detection of Cd(II), Pb(II) and Cu(II) from a synthetic sample solution was performed. The estimated detection limit of the free metal ion is 2pM for Pb(II) and 75pM for Cd(II) using 5min as deposition time.