The aim of this study was to characterize the biological treatment of heavy metal-contaminated water employing Myriophyllum species, namely M. spicatum L. and M. triphyllum. Both species were found to be capable of removing cadmium (Cd) from water; the latter significantly outperformed. Myriophyllum species were treated with 0, 2, 4, 6, 8, 16 mg l(-1) cadmium solutions for 24, 48, 72, 96 h, respectively. Cd uptake of both species was the lowest at 2 mg l(-1) and the highest at 16 mgl(-1). Concentration related cadmium stress on both species exhibit significant difference on pigment levels (8-16 mg l(-1)). These findings contribute to the fact that submerged aquatic plants can be used for the removal of heavy metals. (C) 2004 Elsevier Ltd. All rights reserved.