The fate of antibiotics reaching soils is a matter of concern, given its potential repercussions on public health and the environment. In this work, the potential bio-reduction of the antibiotic amoxicillin (AMX), affected by sorption and desorption, is studied for 17 soils with clearly different characteristics. To carry out these studies, batch-type tests were performed, adding increasing concentrations of AMX (0, 2.5, 5, 10, 20, 30, 40, and 50 μmol L-1) to the soils. For the highest concentration added (50 μmol L-1), the adsorption values for forest soils ranged from 90.97 to 102.54 μmol kg-1 (74.21-82.41% of the amounts of antibiotic added), while the range was 69.96-94.87 μmol kg-1 (68.31-92.56%) for maize soils, and 52.72-85.40 μmol kg-1 (50.96-82.55%) for vineyard soils. When comparing the results for all soils, the highest adsorption corresponded to those more acidic and with high organic matter and non-crystalline minerals contents. The best adjustment to adsorption models corresponded to Freundlich's. AMX desorption was generally <10%; specifically, the maximum was 6.5% in forest soils, and 16.9% in agricultural soils. These results can be considered relevant since they cover agricultural and forest soils with a wide range of pH and organic matter contents, for an antibiotic that, reaching the environment as a contaminant, can pose a potential danger to human and environmental health.
Keywords: Adsorption; Amoxicillin; Desorption; Emerging pollutants; Soils.
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