title: Sorption of fluoroquinolones and sulfonamides in 13 Brazilian soils.
abstract: Animal production is a leading economic activity in Brazil and antibiotics are widely used. However, the occurrence, behavior, and impacts of antibiotics in Brazilian soils are still poorly known. We evaluated the sorption behavior of four fluoroquinolones (norfloxacin, ciprofloxacin, danofloxacin, and enrofloxacin) and five sulfonamides (sulfadiazine, sulfachloropyridazine, sulfamethoxazole, sulfadimidine, and sulfathiazole) in 13 Brazilian soils with contrasting physical, chemical, and mineralogical properties. Fluoroquinolone sorption was very high (Kd≥544 L kg(-1)) whereas sulfonamide sorption ranged from low to high (Kd=0.7-70.1 L kg(-1)), consistent with previous reports in the literature. Soil texture and cation exchange capacity were the soil attributes that most affected sorption. Cation exchange was the most important sorption mechanism for the fluoroquinolones in highly weathered tropical soils, although cation bridging and ion pairing could not be ruled out. Hydrophobic partition played an important role in the sorption of the sulfonamides, but sorption was also affected by non-hydrophobic interactions with organic and/or mineral surfaces. Sorption for both compound classes tended to be higher in soils with high Al and Fe oxihydroxide contents, but they were not correlated with Kd values. No direct effect of soil pH was seen. The fluoroquinolones are not expected to leach even in worst-case scenarios (soils rich in sand and poor in organic carbon), whereas soil attributes dictate leaching potential for the sulfonamides.
authors.affiliation: Laboratório de Ecotoxicologia, Centro de Energia Nuclear na Agricultura - CENA/USP, PO Box 96, 13400-970 Piracicaba, SP, Brazil.
authors.forename: Rafael Marques Pereira
authors.initials: RM
authors.lastname: Leal
authors.forename: Luis Reynaldo Ferracciú
authors.initials: LR
authors.lastname: Alleoni
authors.forename: Valdemar Luiz
authors.initials: VL
authors.lastname: Tornisielo
authors.forename: Jussara Borges
authors.initials: JB
authors.lastname: Regitano
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001938:Brazil; D002412:Cations / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring; D024841:Fluoroquinolones / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D002412:Cations; D024841:Fluoroquinolones; D012987:Soil; D012989:Soil Pollutants; D013449:Sulfonamides
keywords: Retention; Soil pollution; Transport; Veterinary antibiotics; Weathered soils