Atrazine bioaccumulation and biotranformation in cattail (Typha latifolia) over the exposure time

PÉREZ, DÉBORA JESABEL; DOUCETTE, WILLIAM; MOORE, MATTHEW; MENONE, MIRTA LUJÁN

Workshop; 8° Latin American Pesticide Residues Worshop; 2021

Atrazine (ATZ) is a widely used herbicide primarily applied to genetically modified corn fields for weed control. Due to its ubiquitous occurrence in water resources, it is considered a recalcitrant pollutant in aquatics ecosystems. Vascular macrophytes play an essential role in structuring the physical, chemical, and biological characteristics of aquatic ecosystems. Typha latifolia is an emergent macrophyte widely used in phytoremediation process, due to its ability to bioaccumulate contaminants. Some reports have described ATZ bioaccumulation and biodegradation pathways in terrestrial plants1 but there is scarce information for aquatic macrophytes.2 Research goals were to (1) analyze ATZ bioaccumulation and distribution patterns in T. latifolia tissues over the time; and (2) determine ATZ biodegradation metabolites in tissues, as desethylatrazine (DEA) and desisopropylatrazine (DIA). Cattails were hydroponically exposed to 20 µg/L of ATZ (18 exposed plants and 18 non-exposed control plants) at 7, 14, 21, 28, 35 and 42 days. The plants were separated into root, rhizome, stem, and base, middle and upper leaf sections. Atrazine was determined by LC-MS/MS analyses, and DIA and DEA were determined by LC-DAD. Atrazine bioaccumulation pattern, expressed as bio-concentration factor was (in L/kg): middle leaf (81.8 ± 4.8) > upper leaf (66.1 ± 4.3) > base leaf (52.8 ± 2.2) > stem (8.2 ± 0.4) > root (7.2 ± 0.3) > rhizome (5.3 ± 0.2). In belowground tissues DEA and DIA was detected. In leaves, DIA was the main metabolite rather than DEA. Results indicated T. latifolia has the ability to take up ATZ from the media, translocate it from root to shoot, bioaccumulate it in tissues (mainly leaf), and biodegrade via different metabolic pathways. In this sense, T. latifolia could be used in water phytoremediation to bioaccumulate and biodegrade ATZ.