Saflufenacil is an herbicide that is leachable in soil and has the potential to contaminate groundwater, besides having moderate toxicity to aquatic organisms. Some macrophyte species may interfere with the availability of herbicides in water, increasing dissipation in this environment. Thus, the objective of this work was to evaluate the absorption and dissipation of 14C-saflufenacil in water by Egeria densa and Pistia stratiotes. Dissipation was performed with 14C-saflufenacil applied directly in water and quantified by liquid scintillation spectrometry (LSS). The evaluation times were 0, 3, 6, 24, 48, 72 and 96 h after application (HAA) for E. densa and 0, 12, 24, 36, 48, 60, 84 and 108 HAA for P. stratiotes. Absorption was analyzed through plant combustion in a biological oxidizer. The presence of the macrophytes increased the dissipation of 14C-saflufenacil in water. The half-life time (DT50) of the herbicide decreased by 82.6% in the presence of E. densa at 96 HAA. For P. stratiotes, the reduction in DT50 was 94.8% at 108 HAA. The absorption of 14C-saflufenacil was low for both macrophytes during the evaluated time. However, the macrophytes E. densa and P. stratiotes showed potential for the phytoremediation of water contaminated with saflufenacil.
Keywords: Bioremediation; dissipation; macrophytes; radiolabeled herbicide.