Vegetative filter strips (VFS) have been shown to effectively reduce herbicide transport in runoff. However, the efficacy of VFS may be significantly affected by the choice of plant species used. Grasses in the Poacea family have been shown to produce benzoxazinone (Bx) compounds that enhance degradation of the herbicide atrazine. Previous research demonstrated that switchgrass (Panicum virgatum) enhances atrazine degradation in soil, but the degrading phytochemical(s) is/are unknown. Objectives of this research are to: 1) determine if atrazine degradation is different among several switchgrass varieties; 2) identify phytochemicals responsible for degradation; 3) determine if atrazine degradation in soil is affected by switchgrass variety and compare to eastern gamagrass (Tripsacum dactyloides), a known Bx producing species. Degradation was determined in mixtures of atrazine plus root extracts from 7 switchgrass varieties using 16 hour incubations. Three switchgrass varieties degraded between 79% and 85% of atrazine compared to control values. The identification of atrazine metabolites formed and the phytochemicals responsible are presently under investigation. Results from a greenhouse experiment conducted to compare atrazine degradation in soil over 112 days using replications of 2 varieties of switchgrass, eastern gamagrass, and bare soil control samples will be presented. Lastly, batch equilibration experiments are currently being conducted to measure the sorption and reactivity of a Bx compound, DIBOA-glucoside, to pure clay and field soil in the presence and absence of atrazine. Results of these experiments should improve our understanding of chemical sorption and reactivity of Bx compounds. Overall, this work will provide needed information regarding the ability of switchgrass varieties to degrade atrazine and further determine the usefulness of switchgrass for use in VFS.

Phytoremediation of atrazine using switchgrass (Panicum virgatum)

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.