Distribution and Accumulation of Monensin in Water-Sediment-Biota Microcosms Assays.

URRUCHUA, F.C.; MARINO, D.J.; NAVARRO, M.; ALONSO L.L.; SANCHEZ URDAY, C.

Valdivia

Congreso; SETAC Latin America 14th Biennal Meeting; 2021

Society of Environmental Toxicology and Chemistry

The occurrence of veterinary antibiotics in water courses has been reported in the recent years. Particularly monensin (MON) stands out as a drug widely used in animal production and has been quantified in more than 20 water streams from Argentina. However, information about its environmental distribution is still scarce. The objective of the present work was to characterize the distribution and bioaccumulation of MON in microcosm systems of different composition. For this purpose, sediment samples were collected from a site of low agricultural impact previously characterized by the working group (A° El Pescado, BA, Argentina). The microcosm systems were assembled in glass jars with dechlorinated water, in combination with sediment, specimens of an aquatic plant (Pistia stratiotes) and tadpoles (Boana Pulchella). Once assembled, MON was incorporated into each system at a nominal concentration of 250 µg/L and maintained under controlled T and photoperiod conditions for 7 and 14 days. After the assay, all samples from each assay and matrix were pre-treated and analysed by LC-MS/MS. Regarding the biphasic water-sediment systems, MON accumulation was observed in the sediment, reaching between 21 and 52% of the initial aggregate mass. These percentages decreased in the presence of organisms, both individually and jointly. The distribution coefficients calculated in the different scenarios resemble values reported in real environmental scenarios but differ from those expected according to the physicochemical characteristics of the molecule. It is noteworthy the relevance of the soluble fraction of the compound, being the major compartment of occurrence of MON. In relation to the organisms, it was observed that the plant presented levels of MON concentrations in leaves up to 8 times higher than those detected in roots. These values increased in the presence of tadpoles, which presented significantly lower concentrations than the rest of the compartments, with incorporated mass percentages