Occurrence and effects of antibiotics on the environment

Abstract

Antibiotics are one of the most significant discoveries of the 20th century, but over the last few years, a new problem has emerged due to their excessive use and persistence in the environment. The presence of these drugs in ecosystems has led to the spread of antimicrobial resistance, prompting the World Health Organization to warn that by 2050, if nothing changes, 10 million deaths caused by bacterial infections could be reached. For this reason, this study analyzes the occurrence of antibiotics in aquatic environments to determine their risk in ecosystems and for antimicrobial resistance. Different samples from river, sea and around wastewater treatment plants (WWTPs) in Barcelona, Valencia (Spain), Paris (France) and Helsinki (Finland), areas of considerable interest due to their anthropogenic impact and different climate conditions, were examined to determine the occurrence of antibiotics by HPLC-HRMS, using either target analysis focused on 18 antibiotics and suspect screening for the identification of other drugs. The results obtained were used to perform a statistical analysis of environmental factors and to evaluate ecotoxicological risk using the Hazard Quotient. The most frequently detected antibiotics with the highest risk were sulfamethoxazole, metronidazole, azithromycin and tetracycline. On the other hand, the highest concentrations were found in samples near WWTPs, while sea samples have the lowest concentrations due to the dilution effect. Finally, this study shows that these drugs could represent a significant risk to aquatic ecosystems, as in several cases they exceed environmental risk thresholds, demonstrating the need for improved removal treatments for these substances and stricter environmental regulation