Cocaine contamination in Rio de Janeiro waterways

Research led by the Oswaldo Cruz Institute (Fiocruz) has identified cocaine and its primary metabolite, benzoylecgonine, in several rivers and canals within the Rio de Janeiro metropolitan area. The study analyzed water samples collected between July 2022 and June 2023 from five waterways flowing into Guanabara Bay, including the Irajá, Carioca, and Meriti rivers.

Benzoylecgonine was present in every sample, and cocaine was detected in nearly all samples. Researchers noted that contamination levels in these Brazilian waters exceeded those recorded in similar studies in the United States, Spain, and Belgium.

Scientists indicate that the presence of these substances reflects both drug circulation and deficiencies in sewage treatment, as untreated waste allows these substances to reach local waterways. The contamination poses significant risks to aquatic ecosystems; experiments on zebrafish embryos showed increased mortality, physical deformities, and neurological and cardiovascular alterations when exposed to the concentrations found in the rivers.