(RIO DE JANEIRO) Brazilian scientists say they have found traces of cocaine in tiny sharks off the coast of Rio de Janeiro, a sign of pollution they are exposed to.
“We took 13 male and female samples and cocaine was found in all of these animals”, in muscles and liver, Osvaldo Cruz, one of the leaders of the study carried out for the company (IOC/Fiocruz).
The organization said that this is the first time in the world that this has happened.
As predators at the top of the food chain, sharks are considered “sentinel” species for environmental damage.
Photo courtesy of Osvaldo Cruz Foundation, Reuters
A Brazilian sharknose shark (Rhizoprionodon Lalandii) is analyzed in a laboratory in Rio de Janeiro, Brazil.
The analyzed specimens belong to the Brazilian needle shark (scientific name Rhizoprionodon lalandii) and collected between September 2021 and August 2023 along the coast of the Recreio dos Bandeirantes district in western Rio.
Benzylconine, a substance derived from the metabolism of cocaine, was found in their bodies.
“Many studies around the world have already shown the presence of cocaine in aquatic matrices, seawater, rivers and sewers. In Brazil, the world’s second largest market for cocaine, we wondered if the drug had reached the biota. […]. We showed that too [la flore et la faune] actually exposed to this pollution,” explained Enrico Mendes Sachioro.
The main hypothesis, the scientist said, was that the pollution was caused by “disposable consumers” going to the toilet and sewage discharged into the sea “through treatment laboratories”. “International sea transport” is another hypothesis, “but this still needs to be studied,” he said.
As this is a non-migratory species, pollution may have occurred near the Carioca coast.
According to the researchers, the analyzed shark is a species that is consumed in Brazil and other parts of the world, but further studies are needed to determine whether people can be affected by its consumption.
Further analysis is needed to determine the exact effects of cocaine contamination on sharks, including effects on growth or fertility, according to scientists who have already detected other contaminants in these animals. The research results were published in the journal The science of the total environment.
