Azithromycin in the Sabarmati River as an indicator of aquatic environment contamination

Azithromycin, a widely prescribed macrolide for respiratory infections, poses significant environmental risks due to its persistence in aquatic ecosystems. The study investigated the occurrence of azithromycin considering factors like, monthly and seasonal variations, with estimation of their ecological risks in the Sabarmati River, Gujarat, India. A total of 168 samples were collected from six sites, which were extracted using QuEChERS and analyzed via LC-MS/MS. The measured concentrations were 177 µg/L at Narmada Canal (NC), 165.72 µg/L at Indira Gandhi Bridge (IB), 155 µg/L at Middle Town Riverfront (MTRF), 145.2 µg/L at Riverfront Flower Park (RFFP), 187.6 µg/L at Vasna Barrage (VB), and 162 µg/L at the Wastewater Effluent site (WWE). The highest contamination was observed at VB, followed by NC & IB. Monthly variation data showed that azithromycin concentration was highest in August, while May and June recorded the lowest concentrations. Moreover, concentrations of azithromycin were observed to vary seasonally, with the highest levels during the monsoon, followed by the post-monsoon period, and the lowest during the pre-monsoon period. Further, a Risk Quotient (RQ) assessment identified algae as the most vulnerable organisms, while Daphnia magna and fish showed minimal risk. The contamination of azithromycin in the Sabarmati River might be due to pharmaceutical industries, human disposal activities, including other anthropogenic factors. The present findings underscore the need for urgent regulatory measures to monitor and mitigate antibiotic pollution.