Removal of atrazine from submerged soil using vetiver grass (Chrysopogon zizanioides L.)

Abstract

The long-term widespread application of atrazine poses significant threats to the eco-environment and human health. To investigate the potential of vetiver (Chrysopogon zizanioides L.) for phytoremediation of the environmental media contaminated by atrazine, an indoor incubation experiment was conducted in submerged soil over 30 days. Results showed that the chlorophyll level of the vetiver was not significantly affected by exposure to atrazine. Vetiver could take up and accumulate atrazine from submerged soil and peaked around the 20th day with a concentration of 1.0 mg kg−1 in leaf. The metabolites Hydroxyatrazine (HA), deethylatrazine (DEA), Deisopropylatrazine (DIA), and didealkylatrazine (DDA) were detected in the leaf on the 30th day, indicating vetiver could degrade atrazine inside the leaf tissue. The atrazine removal rate in the vetiver planted and unplanted jars were 69.72 and 60.29%, respectively, indicating that 9.43% higher atrazine removal was achieved in the presence of vetiver (p < 0.05). The atrazine dissipation in the submerged soil followed first-order kinetics, the degradation constant was 0.066, and the half-life of atrazine dissipation was shortened by 6.86 days in the presence of vetiver. The present study suggests that vetiver can take up atrazine from submerged soil and accumulate in the leaf, which could then degrade in the leaf. Novelty statement: Although the fate of atrazine in agricultural soils has been extensively investigated through various experiments, little is known about the effect of vetiver grass on atrazine dissipation from submerged soil. With the identification of soil-leaf transportation and four metabolites in vetiver leaf and soils, significantly accelerated atrazine dissipation from the submerged soil was achieved in the presence of vetiver. Particularly, the formation of less toxic dealkylated products in the leaf indicated vetiver is a promising grass for atrazine removal from submerged soil.