Determination of glyphosate, AMPA and glufosinate in water, sediment and fish tissue by UHPLC-MS/MS

DEMONTE, LUISINA D.; MAGNI, FLORENCIA V.; MICHLIG, MELINA P.; REPETTI, MARÍA R.

Panamá

Workshop; 9TH Latin American Pesticide Residue Workshop (LAPRW); 2023

Ministerio de Desarrollo Agropecuario de Panamá (MIDA)

River basins are generally adjacent to agricultural areas where high concentrations of pesticides are applied. Argentina is among the top five countries to adopt genetically modified crops and this influences the amount of glyphosate used, increasing environmental, wildlife and human risks due to chronic exposures.In the Littoral region of Argentina, extensive agriculture and rice production fields are predominant, both associated to natural wetlands that serve as alternative and temporary habitats for aquatic organisms such as fish.In this scenario, water, sediment and fish are exposed to many pesticides, and as a consequence humans are too.The objective of this study was to determine glyphosate, its main degradation product AMPA, and glufosinate in waters, sediments, and fish tissues from production areas around the lower course of the Salado river in Santa Fe Province.All samples were analyzed following a method based on the pre-column derivatization of glyphosate with FMOC-Cl and reverse phase UHPLC-MS/MS determination.Waters: acidification and neutralization of the sample, derivatization and cleanup with dichloromethane.Sediments: extraction and pre-treatment of the sample with potassium hydroxide, derivatization and cleanup with dichloromethane.Fish tissue: extraction and pre-treatment of the sample with water and dichloromethane, derivatization and cleanup with dichloromethane.To obtain a better analytical performance, the MS/MS parameters were optimized by design of experiments. First, a fractional factorial screening design and then a central composite design were used to optimize the significant factors, resulting in a two-fold increase of the analytical for all the analytes.In this way, were achieve LOQs of 0.6 µg/L in water and 10 µg/kg in sediments and tissue fish, for the three analytes.Muscle fish tissues showed very high incidence of pesticide residues, the maximum detected concentrations being 187 μg/kg, 3116 μg/kg, and 677 μg/kg for glyphosate, AMPA and glufosinate, respectively.In sediments the concentrations were lower with a maximum glyphosate concentration of 24 µg/kg, while AMPA and glufosinate were not detected.The screening of pesticides in waters and sediment samples from a rice field evidenced the presence of glyphosate and AMPA, among other compounds. The maximum concentrations of glyphosate and AMPA found in water were 1.4 and 3.4 µg/L and in sediments 131.2 and 185.0 µg/kg, respectively. Glufosinate was not detected neither in waters or sediments. The results in fish tissue are interesting because it was found that AMPA (persistent) bioaccumulated in liver and muscle tissue of all collected fish. Interestingly, the results from fish evidenced the bioaccumulation of AMPA in liver and muscle tissues of all collected samples.These results highlight the need for periodic monitoring due to the high concentrations of pesticides found and its potential risk in a very important food production region of Argentina.