Occurrence of 28 Human and Veterinary Antibiotics Residues in Waters, North-Eastern Tunisia by Liquid Chromatography-Tandem Mass Spectrometry

Drug residues are now ubiquitous in the environment due to the extensive and widespread use for animal and human health care. Current technologies do not allow to completely remove drug residues during waste water treatment process. Consequently, drug residues are widespread in the aquatic environment and present thus potential impacts on biodiversity, ecosystem functioning, and public health. As a result, their residues have attracted particular attention from government and research community. High concentrations of antibiotic residues detected in the environment have prompted scientists to advocate for the implementation of various laws around the world. This work aims to contribute to the lack of information on this emerging and essential subject. Twenty-eight antibiotics including five tetracyclines, two macrolides, seven fluoroquinolones, and seven sulfonamides were analyzed in the input and output of two wastewater treatment plans (WWTP) in Tunis, in Northern Tunisia, in a tap and well water. The quantification was performed using online SPE-LC-MS/MS after the sample’s extraction/purification with offline SPE. At least 19 drugs were present at the quantifiable level. In the input and output of WWTP, drug residues were determined at high level with the Σ28drugs can be up to 239.8 ± 47.1 ng/L and 139.4 ± 31.9 ng/L, respectively. One WWTP was not operational during the sampling. The concentration level in the output was similar to which found in the input (no elimination process). Another WWTP allowed eliminating only 48% of the Σ28drugs. As a result, the Σ28drugs were detected at 109.5 ± 25.5 and 36.8 ± 8.7 ng/L respectively in well and tap water.