Screening of Commonly Used Antibiotics in Fresh and Saltwater Samples Impacted by Aquacultures: Analytical Methodology, Occurrence and Environmental Risk Assessment

Abstract

Traditionally, antibiotics have been used to treat human and animal diseases caused by pathogenic bacteria. The aquaculture industry, which is massively expanding currently, also makes use of several antibiotic classes, resulting in potential antibiotic residues in the surrounding aquatic environment, as well as the cultured products raising bacterial resistance. The aim of this study was the optimization, validation, and application of a solid-phase extraction (SPE) method in combination with liquid chromatography (LC)-LTQ/Orbitrap mass spectrometry in order to determine the most commonly used antibiotics in waters sampled from fish farms, both saltwater and freshwater, located in Greece. Under optimum conditions, the method was validated, achieving recoveries in the range of 57.7% (for sulfamethoxazole in river water) to 95.8% (for florfenicol in river water). The method quantification limits were within the range of 0.25 and 10 ng·L−1 in all cases, with relative standard deviations (RSDs) < 15.9%. The application of the proposed methodology revealed the presence of oxytetracycline and trimethoprim traces. Finally, an assessment of the environmental risk posed by the detected antibiotics was performed, calculating either the risk quotient (RQ) for three trophic levels (8.013 × 10−6 < RQ < 0.496) or the mixture RQ (0.005 < RQ < 0.682), proving that in all cases, the risk was medium to low.

Screening of Microplastics in Aquaculture Systems (Fish, Mussel, and Water Samples) by FTIR, Scanning Electron Microscopy–Energy Dispersive Spectroscopy and Micro-Raman Spectroscopies

“…Mussels (Mytilus galloprovincialis) were hand-collected from a fish farm in Thesprotia (Epirus, Greece), while sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) samples were obtained from an aquaculture also located in the Northern Ionian Sea. A map of the sampling area was reported in a previously published study from our lab [47]. Before MP separation, mussel and fish samples were stored whole at −20 • C.…”

High-Efficient Elimination of Spiramycin by Fe3O4/ZSM-5/Sch via Heterogeneous Photo-Fenton Oxidation at Neutral pH

“…Spiramycin (SPM), a broad-spectrum macrolide antibiotic, is extensively employed in the livestock industry and clinical hospital treatments [1,2]. Owing to the incomplete absorption of SPM within the animal's intestinal tract, a substantial quantity of unmetabolized SPM and its metabolites are excreted externally via urine and feces, subsequently entering urban wastewater treatment plants [3]. However, conventional wastewater treatment facilities cannot entirely remove antibiotics, leading to their eventual release into aquatic and terrestrial environments through treated wastewater and sewage sludge [4].…”