processes Review Tetracycline and Sulfonamide Antibiotics in Soils: Presence, Fate and Environmental Risks Manuel Conde-Cid 1, Avelino Núñez-Delgado 2 , María José Fernández-Sanjurjo 2 , Esperanza Álvarez-Rodríguez 2, David Fernández-Calviño 1,* and Manuel Arias-Estévez 1 1 Soil Science and Agricultural Chemistry, Faculty Sciences, University Vigo, 32004 Ourense, Spain;
[email protected] (M.C.-C.);
[email protected] (M.A.-E.) 2 Department Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University Santiago de Compostela, 27002 Lugo, Spain;
[email protected] (A.N.-D.);
[email protected] (M.J.F.-S.);
[email protected] (E.Á.-R.) * Correspondence:
[email protected] Received: 30 October 2020; Accepted: 13 November 2020; Published: 17 November 2020 Abstract: Veterinary antibiotics are widely used worldwide to treat and prevent infectious diseases, as well as (in countries where allowed) to promote growth and improve feeding efficiency of food-producing animals in livestock activities. Among the different antibiotic classes, tetracyclines and sulfonamides are two of the most used for veterinary proposals. Due to the fact that these compounds are poorly absorbed in the gut of animals, a significant proportion (up to ~90%) of them are excreted unchanged, thus reaching the environment mainly through the application of manures and slurries as fertilizers in agricultural fields. Once in the soil, antibiotics are subjected to a series of physicochemical and biological processes, which depend both on the antibiotic nature and soil characteristics. Adsorption/desorption to soil particles and degradation are the main processes that will affect the persistence, bioavailability, and environmental fate of these pollutants, thus determining their potential impacts and risks on human and ecological health.