Behaviour of sulfadimethoxine on farming soils from Buenos Aires, Argentina

MA. LAURA GALOTTA; ANALÍA IRIEL; ALICIA FERNÁNDEZ CIRELLI

ENVIRONMENT, DEVELOPMENT AND SUSTAINABILITY

Springer Netherlands

Año: 2022

1387-585X

Therapeutic drugs are routinely supplied to farm animals to prevent bacterial infections,coccidiosis, and as growth promoters as intensive livestock production systems becomemore common. It is required to develop local data to be used in environmental risk assessmentsin order to predict the fate of these compounds. In this work, a sulfadimethoxine(SDM) adsorption study was conducted in soils used for agricultural and livestock activities.To carry out the adsorption/desorption experiments, two soil samples from the PampaPlain region (Argentina) were obtained. Both soils, denoted as MS and US, presented similarphysicochemical properties and textural classification of clay loam. Batch experimentsrevealed that the adsorption/desorption isotherms of SDM on soils were well adjustedto the Freundlich model, where adsorption constants resulted in 5.35 and 8.94 g 1–1/nmL 1/n g−1 for MS and US, respectively. These values were normalized according to theorganic matter content in both soils, obtaining values of 171.52 and 195.62 μg1−1/nmL1/ng−1, respectively. Regarding kinetics results, adsorption processes followed a pseudosecond-order law whose rate constants showed major differences, being 3.8 × 10–3 and 0.012 g g−1 min−1, respectively. Moreover, the equilibrium period ranged from a few minutes(US) to 5 h (MS) suggesting that SDM mobility in soils could be different besides theSDM adsorption constants were similar in both. In conclusion, equilibrium studies couldnot be sufficient to predict the quantity of SDM adsorbed on soils because the adsorbedquantity predicted only from equilibrium studies could be overestimated in a real-lifescenario.