Dissolved and colloidal fraction transport of antibiotics in soil under biotic and abiotic conditions

Veterinary antibiotics, leached from contaminated manure that is applied as fertilizer, could be transported to surface water as runoffor infiltrated to groundwater after a significant rainfall. The main objective of this study was to evaluate the transport behaviour of ten antibiotics belonging to four different groups in soil through the column leaching study under biotic and abiotic conditions. Among compared antibiotic groups, tetracyclines (TCs) were found to have no residual in the leachate and mainly remained sorbed to the fixed column soil ranging 34~81% of initially applied mass. In contrast, sulfamethazine (SMTs), one of the sulfonamides (SAs) group, was mostly recovered in the leachate at the ranges of 74~83% of the total mass applied. Also, colloidal-facilitated transport of antibiotics was observed. Depending on the antibiotics, recovered mass of colloidal-facilitated transport was 0.4~22.7% for biotic and 0.2~62.5% for abiotic treatment as compared to total mass applied in soil. In general, a less mass was recovered in biotic leachate and soil columns indicating that microorganism activity might be a minor attenuation mechanism. Results indicated that phase partitioning of antibiotics would be a major factor to be assessed in evaluation of fate and transport of antibiotics in soil.