Cocaine found in sharks’ bodies in Rio de Janeiro

Brazilian researchers have identified the presence of cocaine and benzoylecgonine (a metabolite of cocaine or coca leaves) in sharpnose sharks (Rhizoprionodon lalandii) in Brazil. The study was published in the international journal Science of The Total Environment in July 2024.

The data was prepared at the Federal University of Santa Catarina, in conjunction with the Federal University of Rio de Janeiro and the Oswaldo Cruz Foundation. The study analyzed 13 sharks captured in the seas of Rio de Janeiro.

About the study

The journal Science of The Total Environment revealed that the study investigated the presence of COC (cocaine) and BE (benzoylecgonine) levels in Brazilian sharpnose sharks. The results revealed that 100% of the sharks analyzed tested positive for the presence of cocaine. For the presence of benzoylecgonine, 92% of them tested positive.

The concentrations of cocaine found were more than 3 times higher than benzoylecgonine. The presence of cocaine in the muscles (23.0 μg kg −1 ) was three times higher, compared to the amount found in the liver (7.0 μg kg −1 ) of the animals.

The study analyzed the difference in the presence of the drug between males and females. In females, there are higher concentrations (40.2 ± 35.8 μg kg −1) of cocaine in the muscles, compared to males (12.4 ± 5.9 μg kg −1 ).

The analysis also reveals that the level of benzoylecgonine is equal to that of cocaine in non-pregnant females. This points to a relationship between the presence of benzoylecgonine and the weight of the sharks. The presence of cocaine is linked to the presence of the metabolite benzoylecgonine in females, indicating that systemic metabolism is more efficient in females.