The effects of temperature on the bioaccumulation of the phenylurea herbicide isoproturon (IPU) and on the growth inhibition induced on two freshwater rooted macrophytes--Elodea densa and Ludwigia natans--were investigated using indoor microcosms. The experimental protocol was based on five temperatures (12, 16, 20, 24, and 28 degrees C) and two contamination levels of the water column (30 and 60 micrograms IPU.liter-1), plus a control condition. Variations in temperature had little effect on the decrease in [IPU] in the water column during the 21-day experiment. The IPU concentration in the two macrophyte species was not significantly modified by the large range of temperatures when results were expressed using the concentration criterion. IPU burdens in the E. densa cuttings, on the other hand, increased significantly when the temperature rose from 12 to 28 degrees C; small differences were observed between the two exposure conditions, in relation to the antagonistic effects of IPU and temperature on the growth of the cuttings. Bioconcentration factors in the plants (stems + leaves) were close to 10 and 13 after exposure to 30 and 60 micrograms IPU.liter-1, respectively.