Aquatic Macrophytes in the Remediation of Atrazine in Water: A Study on Herbicide Tolerance and Degradation Using <i>Eichhornia crassipes</i>, <i>Pistia stratiotes</i>, and <i>Salvinia minima</i>

Aquatic macrophytes can be used for herbicide remediation provided they exhibit tolerance to the contaminants. This research assessed the remediation potential of <i>Salvinia minima</i>, <i>Echhornia crassipes</i>, and <i>Pistia stratiotes</i>, some common aquatic macrophytes native to Brazil, and their tolerance to atrazine, an herbicide commonly detected in waterbodies. Plants were cultivated under controlled conditions with five atrazine concentrations (0, 2, 20, 200, and 1000 μg L^-1) for 15 days. <i>S. minima</i> and <i>E. crassipes</i> tolerated atrazine concentrations equal to or less than 20 μg L^-1 and died at 200 and 1000 μg L^-1, indicating the herbicide's potential toxicity and its selectivity against sensitive species. <i>P. stratiotes</i> tolerated the herbicide concentration up to 200 μg L^-1 and had its growth reduced at 1000 μg L^-1. All species demonstrated the ability to reduce atrazine concentrations in water at 20 μg L^-1 or lower, <i>E. crassipes</i> being the most efficient, reducing concentrations by 43% and 22% at 2 and 20 μg L^-1, respectively. Atrazine levels within Brazilian (2 μg L^-1 by CONAMA 2005) and European (0.1 μg L^-1 by Directive 2013/33) regulatory limits do not selectively affect these species. Thus, they show potential for use in arazine phytoremediation programs.