Sharks intoxicated with cocaine detected «for the first time in the world» in Brazil

Rio de Janeiro .- A group of scientists detected, «for the first time in the world», sharks intoxicated with cocaine in Brazil, as disclosed this Tuesday by the Oswaldo Cruz Foundation (Fiocruz), an organization linked to the Ministry of Health.

The study, already published in the journal ‘Science of The Total Environment’, identified the presence of cocaine in 13 sharks of the species Rhizoprionodon lalandii, known as the Brazilian beaked dogfish.

The samples were collected in the Recreio dos Bandeirantes neighborhood, in the western area of ​​Rio de Janeiro, between September 2026 and August 2026, within a project to monitor possible changes in marine life, whether natural or caused by the human action.

In the 13 specimens analyzed, the substance was detected and even in 12 of them they found benzoylecgonine, which is the main metabolite of cocaine.

«The result is impressive,» said pharmacist Enrico Mendes, one of the authors of the study, along with biologist Rachel Ann Hauser-Davis. Both are part of the Fiocruz Environmental Health Evaluation and Promotion Laboratory.

To reach this «unpublished» conclusion, they analyzed muscle tissue and the liver of thirteen sharks, three males and ten females.

«In Brazil, there are studies that have already detected cocaine in the water and in some aquatic beings, such as mussels. Our analysis is the first to find the substance in sharks,” explained Mendes.

Intoxicated via sewer

Researchers believe that the animals became intoxicated from «overexposure» to the «large amount» of cocaine that is discarded into the sea through the sewers of Rio de Janeiro.

They were also surprised to find a higher concentration of cocaine in the muscles than in the liver of the sharks analyzed, which may indicate the «abundant» presence of cocaine in the marine environment of Rio.

«The sharks would be becoming poisoned in various ways, either by inhabiting the region or feeding on other contaminated animals,» Mendes noted.

Ann Hauser-Davis stated that the Brazilian beaked dogfish is a non-migratory species that lives near the coast, so it surely became poisoned in that western area of ​​Rio, the most populous and the fastest growing in the city, with almost three million inhabitants, according to the last census.

«It is believed that there may be an impact on the growth, maturation and, potentially, the fecundity of sharks, since the liver acts on the development of embryos,» the researcher warned.

“Minimal” risk to human health
Regarding possible impacts on human health, researchers believe that these are «minimal», since contact with water is sporadic and it is not used for eating or drinking.

However, Ann Hauser-Davis recalls that «many times» these types of sharks are sold «irregularly» in the markets, so more studies would be needed to answer this question.

In this sense, she announced that they intend to collect and analyze samples of water and other animals, from that and other regions of the coast of Rio de Janeiro, to see the scope of this phenomenon.

The most recent world report from the United Nations Office on Drugs and Crime places Brazil as one of the largest global consumers of cocaine.

The country is also one of the main exit routes, through its ports, for drugs that are produced in other countries in the region, such as Colombia, Peru and Bolivia.