The Lorado uranium mill tailings, near Uranium City, Saskatchewan are characterized by low pH, high salinity and high concentrations of elements such as copper, nickel, lead, uranium, vanadium and zinc. In 1982, we measured the concentrations of 30 elements in plant tissues of water sedge (Carex aquatilis Wahl.) , a natural invader of wet tailings. Concentrations of copper, lead, uranium and vanadium in plants on the tailings were higher than in plants from background sites off the tailings . More detailed analyses of these elements in 1983 showed that relative concentrations in plant parts for all four metals were: roots > rhizomes > green leaves. Radium-226 and uranium were elevated in aboveground tissue (leaves) compared to samples from background sites off the tailings .