Measurement of ampicillin and penicillin G antibiotics in wastewater treatment plants during the COVID-19 pandemic: A case study in Isfahan

Background: In recent years, the world has faced with the COVID-19 pandemic, followed by a significant increase in the use of antibiotics to control the COVID-19 and other secondary infections. The nonbiodegradable characteristics of antibiotics and their residues in the environment leads to increased microbial and drug resistance. Therefore, due to the high importance of antibiotics, two antibiotics, ampicillin and penicillin G, were studied in Isfahan municipal wastewater treatment plants (WWTPs). Methods: Sampling was performed for two months during 13 sampling periods and antibiotics were measured using high-performance liquid chromatography with UV detector (HPLC/UV) instrument. Results: Ampicillin and penicillin G were identified in all samples taken from the both WWTPs. The average concentration of penicillin G in WWTP E and S at the influent, effluent and its removal efficiency were 1050.54 ± 761.43 μg/L, 52.89 ± 49.27 μg/L, 89.80 ± 19.42%, 2055.12 ± 1788.08 μg/L, 143.01 ± 162.59 μg/L and 82.76 ± 21.85%, respectively. Also, the average concentration of ampicillin in WWTP E and S in the influent (796.44 ± 809.6 and 447.1 ± 322.39 μg/L), effluent (48.94 ± 24.25 and 90.31 ± 75.91 μg/L), and its removal efficiency (86.22 ± 19.84% and 66.85 ± 24.88%) were determined. Conclusion: In two studied WWTPs, the concentration of antibiotics was higher during the COVID-19 pandemic in comparison with previous studies. The statistical analysis showed that there was no significant relationship between the concentration of antibiotics in WWTPs (P < 0.05). Also, the statistical results indicated that the correlation is not significant between removal efficiency of antibiotics and removal efficiency of wastewater main parameters.