Six vascular plant species (sweet gum, black willow, pickleweed, smartweed,
water-lily and duckmeat) were used to determine the uptake and transformat
ion of perchlorate at three concentrations (0.2, 2.0, and 20.0 mgl(-1)) for
10 days under laboratory conditions. Perchlorate uptake followed a first-o
rder reaction, with rate constants ranging between 0.001 to 0.007 h(-1). Ac
cumulation of perchlorate was between 0 to 981 mg kg(-1) of plant weight fo
r various plants. Based on the results the accumulation of perchlorate was
in the order: smartweed > pickleweed > sweet gum > water-lily > willow. Ana
lysis of plant tissues (roots, stems, and leaves) confirmed the presence of
transformation products, chlorate, chlorite and chloride. The distribution
of perchlorate and its products indicate that the transformation reaction
occurred in each tissue independently of the other and accumulation of bypr
oducts was significantly higher in leaves than in roots or stem. No externa
l signs of perchlorate toxicity were observed at these high concentrations
in plant tissues suggesting that these plant species show potential for phy
toremediation.