Metalaxyl and simazine toxicity to and uptake by Typha latifolia

This research focused on the potential use of common cattails (Typha latifo lia) for removing metalaxyl and simazine residues from contaminated water. Specifically, it established toxicity thresholds to the herbicide simazine and characterized the uptake and distribution of simazine and metalaxyl by the plants. Simazine tolerance levels were determined by exposing plants to a series of six concentrations (0-3.0 mg L-1) in aqueous nutrient media fo r 7 days. Metalaxyl toxicity was not evaluated because other studies indica ted it was relatively nontoxic to plants. Toxicity endpoints measured inclu ded fresh mass production after 7 days of exposure and 7 days postexposure. Pesticide uptake and distribution were determined by growing plants in nut rient media amended with C-14-ring-labeled metalaxyl (0.909 mg L-1) or sima zine (0.242 mg L-1) for 1, 3, 5, or 7 days. Plants were dissected, and tiss ues were combusted and analyzed by liquid scintillation spectroscopy. Catta il fresh mass production was reduced 84 and 117% at 1.0 and 3.0 mg L-1 sima zine, respectively, after 7 days of exposure. Metalaxyl and simazine activi ty in solution was reduced 34 and 65%, respectively, after 7 days. By day 7 , activity from both pesticides was detected predominantly in the leaves. U ptake of each pesticide was correlated with water uptake throughout the 7 d ays. These results suggest that the common cattail may be a good candidate for incorporation into a phytoremediation scheme for metalaxyl and simazine .