Rivers at risks: The interplay of "COVID kit" medication misuse and urban waterway contaminants

This study investigates the environmental impact of the widespread use of "COVID Kit" drugs-azithromycin (AZI), ivermectin (IVE), and hydroxychloroquine (HCQ)-in urban rivers of Curitiba in Brazil, during and after the COVID-19 pandemic. The research focuses on the occurrence and concentrations of these pharmaceuticals in water and sediment samples collected from key urban rivers. Concentrations of AZI, IVE, and HCQ in water ranged from 326 to 3340 ng/L, 130-3340 ng/L, and 304-3314 ng/L, respectively, while in sediment, they ranged from 18 to 249 ng/g, 21-480 ng/g, and 38-673 ng/g, respectively. Results indicate a significant increase in AZI, IVE, and HCQ concentrations during the pandemic. Concentrations of these drugs peaked in September 2020 and March 2021, declining after the start of Brazil's vaccination campaign. However, the levels of these pharmaceuticals remained elevated in some areas even after the decline in their usage. Environmental risk assessments were conducted to evaluate the potential ecological hazards posed by these pharmaceuticals, revealing the long-term persistence of these drugs in aquatic environments and their potential to contribute to antimicrobial resistance. The findings of this study underscore the critical need for robust regulatory measures and improved wastewater treatment processes to prevent pharmaceutical contamination in urban water systems, particularly during global health crises.