Sorption of Sulfachloropyridazine in Brazilian Soils

Sulfonamides are among the most widely employed antibacterial in veterinary medicine. Because a substantial proportion of sulfonamides are excreted unchanged as parent compounds after administration or are excreted as their metabolites through urine and feces, their presence in soils is a matter of concern. Adsorption and desorption are important processes that influence the transport, transformation and bioavailability of antimicrobials in soils, and data related to sorption capacity are therefore needed for environmental risk assessments. The sorption potential of sulfachloropyridazine (SCP) was assessed in four Brazilians soils using batch equilibrium experiments. The adsorption/desorption data fit well Freundlich isotherms. The sorption coefficients (KD) ranged from 1.00 to 4.48 cm3 g-1, and the Freundlich adsorption coefficient (KF) ranged from 1.89 to 5.63 µg1-1/n (cm3)1/n g-1 showing that SCP adsorption is generally low in the studied soils. The results were compared with previously published data obtained for the sorption of other sulfonamides in the same four soils.