Temporal and spatial trends in the occurrence of human and veterinary antibiotics in aqueous and river sediment matrices.

The occurrence of 15 antibiotics belonging to three different groups, tetracyclines (TCs), sulfonamides (SAs), and macrolides (MLs), mainly used to prevent or treat illness for humans and also to control disease or to promote the growth for animals was studied in aqueous and sediment matrices. The result of spatial and temporal statistical analysis revealed that measured concentrations of individual antibiotics were significantly different depending on sampling location and time periods for aqueous and sediment samples. High concentrations of human-used antibiotics were detected downstream of a wastewater treatment plant, and animal-used antibiotics were mainly found in a region with significant agricultural activity. Generally, the highest concentrations of antibiotics for both water and sediment samples were measured in winter indicating that low flow conditions and cold-water temperatures might enhance the persistence of these compounds. Furthermore, a pseudo-partitioning coefficient(P-PC) was introduced to provide a better understanding of the partitioning of antibiotics into the sediment. Different P-PC values were found depending on the sorption characteristics of the individual antibiotics. Sediment samples showed a greater detection frequency and a much higher concentration compared to aqueous samples taken at the same site. Since microorganism antibiotic resistance can develop in sediments, the importance of analyzing this matrix is underscored.