Uptake and degradation of atrazine utilizing phytoremediation technology with switchgrass (Panicum virgatum)

Abstract

Atrazine is a widely used herbicide in agriculture. Non-point source (NPS) contamination of groundwater and drinking water may pose a significant threat to humans, wildlife, and the environment. Phytoremediation may provide a cost-effective strategy for reducing NPS contamination from agricultural runoff. Previous laboratory and greenhouse studies have shown that switchgrass (Panicum virgatum) and other prairie grasses can enhance atrazine degradation in contaminated soils. Phytoremediation is partially a result of microbial processes in the rhizosphere. Degradation may also occur within the plant biomass; however the extent to which this occurs remains unknown for phytoremeidation of contaminated soils. We hypothesize that switchgrass plants have the capacity for degrading atrazine. The goal of this study was to: 1) characterize the ability of switchgrass plants to accumulate atrazine from soils; 2) quantify the amount of degradation occurring in the plant; and 3) quantify the amount of degradation occurring in the rhizosphere. Switchgrass seedlings were transplanted in autoclaved and non-autoclaved sand containing 10 μg of atrazine per gram of sand. Treatments were sacrificed on Days 0, 15, and 30. Sand and plant tissue were extracted via mechanical shaking and tissue grinding, respectively. The extracts were analyzed on a gas chromatograph equipped with a thermionic specific detector to determine the concentration of atrazine and metabolites in sand and plant tissues.