Simazine toxicity and uptake by parrotfeather

摘要

The potential use of Myriophyllum aquaticum L. (parrot-feather) for removing simazine residues from contaminated water was examined by establishing toxicity thresholds and characterizing the uptake and distribution. Toxicity thresholds were determined by growing plants for 7 d in nutrient medium amended with 0, 0.01, 0.03, 0.1, 0.3, 1.0, or 3.0 mg simazine/L. Measured endpoints included: fresh biomass production, stem elongation, and branch production. Pesticide uptake and distribution within plants was determined by growing plants in nutrient medium amended with [~(14)C] ringlabeled simazine at concentrations of approximately 0.242 mg/L simazine. Plants were randomly harvested after exposure, dissected into individual parts, combusted, and analyzed by liquid scintillation counting. In comparison to unexposed plants, fresh weight gains were reduced 47, 98, and 105 percent at 0.3, 1.0 and 3.0 mg/L simazine, respectively, after 7 d exposure. Elongation was reduced 60 and 49 percent at 1 and 3 mg/L,respectively, and branch production was reduced 55, 95, and 95 percent at the 0.3, 1, and 3 mg/L, respectively. Simazine activity in plant-containing solution was reduced 9, 18, 31, and 49 percent, after 1, 3, 5, and 7 days, respectively. Activity levels did not decline significantly in reference solutions lacking plants. By day 5, [~(14)C] activity was detected predominantly in leaves. Simazine uptake was correlated with water uptake throughout the 7 days. Activity in non-plant-containing solution remained relatively constant throughout the experimental period. These results suggest that parrotfeather may be a good candidate for incorporation into a phytoremediation scheme for simazine.