Aquatic plants mitigate pollution by enhancing the degradation of atrazine and diuron present in agricultural runoff

Vegetated ditches have been demonstrated to be an effective method for pollutant remediation. This study assesses the removal potential and pathways for herbicide runoff pollution utilizing Canna indica, Thalia dealbata, Typha latifolia, and Juncus effuses ditches. Resultes show these vegetated ditches significantly outperform unvegetated ones in removing atrazine and diuron during runoff events (p < 0.05). The removal rates of atrazine and diuron varied among the four aquatic macrophytes, with C. indica and T. latifolia exhibiting the highest efficiencies, achieving 43.02–72.61% and 56.42–53.11% removal, respectively, under varying runoff pollution. The half-lives of herbicides were significantly reduced from 231.01 to 693.15 h in unvegetated ditches to 99.02–230.05 h in vegetated ones. Furthermore, the release rates of herbicides were significantly reduced from 48.95 to 55.79% in unvegetated ditches to 34.10–42.32% in vegetated ones, particularly during high-dose rainfall events (p < 0.05). Mass balance analysis indicated that biodegradation was the primary removal pathway for herbicides (atrazine 36.20%; diuron 45.76%), followed by sorption (atrazine 6.00%; diuron 12.19%) in vegetated ditches. Plants boosted biodegradation, by 0.5 times for diuron and 1 time for atrazine. The study confirms that vegetated ditches effectively reduce herbicide runoff pollution.