Study of uptake, translocation, and metabolic behavior of pesticides in water milfoil

Water milfoil is a sediment-rooted macrophyte contributing to the aquatic ecosystem, and the risk evaluation of pesticides on this new assessment species has attracted much attention. Knowledge of the shoot/root uptake, inner-plant translocation, and the metabolism of pesticides in water milfoil is essential for a detailed risk assessment and understanding toxicological mechanisms thereof; however, the behaviors have not been studied in detail. Using model studies, the author clarified shoot and root uptake dynamics of 3-phenoxybenzoic acid via water and sediment exposure, respectively, followed by transportation and metabolism at each plant portion; uptake and metabolism kinetics of simple phenols amended with regression analysis on physico-chemical parameters of the compounds; detailed metabolic fate of flumioxazin in various aquatic plants/phytoplankton, and an interspecies comparison. Similar approaches are fully applicable to clarifying the fate of pesticides in water milfoil and are expected to be useful for implementing advanced risk characterizations.