Quantification of saflufenacil fate in water using two species of macrophytes

Abstract

Saflufenacil is a highly persistent herbicide in the environment, and is very toxic to aquatic organisms such as algae and fish. It is a highly mobile product in the soil, often reaching groundwater and contaminating aquatic ecosystems. However, some algae may produce substances that interfere in the degradation of the herbicide, making the dissipation of the product in the environment faster. No studies have been registered quantifying the potential of macrophytes to degrade 14C-saflufenacil, therefore, studying the possibilities of mitigation of this herbicide using these species is of paramount importance for the preservation of the environment. The objective of this research will be to study the potential of Elodea densa and Pistia stratiotes in influencing the degradation of 14C-saflufenacil. Four different densities of both algae (0, 250, 400 and 500 g dry mass m-3) will be used. In stainless steel tanks containing ultrapure water, the same known radioactivity of 14C-saflufenacil will be applied together with the different densities of both algae and the radioactivity will be measured by liquid scintillation spectrometry (ECL) at 0, 2, 4, 24, 48, 72 and 96 hours after application (HAA). After the last analysis (96 h), radiographs will be taken on a radioscanner to know to which parts of the plant the herbicide has translocated. After the images, the plants will be oxidized in a biological oxidizer for the quantification of the absorbed residue and analysis of the mass balance. With this study, the chosen macrophytes are expected to accelerate considerably the degradation of 14C-saflufenacil in water, as well as to absorb the herbicide, making the water cleaner for consumption.