Occurrence of pharmaceuticals in selected wastewaters, the Las Vacas River, and its Tributaries in Guatemala

ABSTRACT Emerging contaminants, including pharmaceuticals, pose risks to human health and aquatic environments. In Guatemala, their research remained limited; as such, this study evaluates 35 pharmaceuticals, including antibiotics and antipyretic drugs, in wastewater and river water. In wastewater, antibiotics' detection frequency ranges from 7 to 93%, and the highest concentration was observed for trimethoprim at 1,790 ng/L. The detection frequencies of all antipyretics were above 91%, with maximum concentrations of acetaminophen, ibuprofen, naproxen, and ketoprofen at 68,200, 7,230, 1,850, and 9,430 ng/L, respectively. In contrast, river water exhibited antibiotics at concentrations between 1.42 and 647 ng/L. The maximum concentrations of acetaminophen, ibuprofen, and naproxen were 8,580, 7,860, and 2,420 ng/L, respectively. However, river water exhibited both a higher detection frequency, with 24 pharmaceuticals found in a greater percentage of its sampling points than in wastewater, and a higher median concentration in 26 compounds. The highest median concentration in wastewater was in caffeine, 4,210 ng/L, while in river water, it was ibuprofen, 848 ng/L. Caffeine exhibited the highest concentration in both wastewater, 77,000 ng/L, and river water, 26,400 ng/L. These findings align with data from neighboring countries, providing valuable insights into the occurrence and distribution of these contaminants in Guatemala.