Comprehensive evaluation of antibiotic pollution in a typical tributary of the Yellow River, China: Source-specific partitioning and fate analysis

The partitioning and migrating of antibiotic residues pose a considerable pollution to the river environment. However, a source-specific approach for quantifying the fate of antibiotics is lacking. To further elucidate the migration behavior of antibiotics from different pollution sources in aquatic environments, we introduced a source-specific partition coefficient (S-Kp) based on Positive Matrix Factorization (PMF) model to improve the multimedia model. This study identified six sources of antibiotic pollution in the water and sediment of the Fenhe River. Farmland drainage contributed 2.6 times more antibiotics to sediment than to surface water, whereas livestock sources contributed 0.3 times less to sediment than to water. High S-Kp values were primarily obtained from livestock, aquaculture, and farmland drainage pollution sources, with an average S-Kp value exceeding 200 L/kg. Sulfaquinoxaline (SQX) in sulfonamides (SAs) from livestock sources exhibited the highest S-Kp value of 34,740.04 L/kg. The predicted environmental concentrations indicated that almost 99 % of the antibiotics from the six sources remained in the water phase, with the highest contribution (99.9 %) of azithromycin (AZM) from livestock, pharmaceutical wastewater, and domestic sewage. This study provides novel insights into the migration of antibiotics from source-specific partitions in multimedia environments of watersheds.