Study Finds Cocaine in Sharks Along the Coast of Brazil

Reports show that sharks near the coast of Brazil have tested positive for cocaine, marking the first instance of the drug being found in freely swimming sharks, according to researchers.

Researchers noted that the concentrations of cocaine and BE found in the sharks were higher than what had been reported in previous studies on fish and other aquatic organisms, surpassing them by up to two orders of magnitude.

The sharks were captured by fishing fleets in the Recreio dos Bandeirantes neighborhood off the coast of Rio de Janeiro in southeastern Brazil between September 2021 and August 2023.

Cocaine Detected in All 13 Specimens

Out of the 13 sharks, three were males and the remaining ten were females. Five of the female sharks were pregnant, as per the study authors.

Researchers discovered cocaine in both the liver and muscle tissues of all 13 sharks, with 12 out of 13 testing positive for BE.

The average concentration of cocaine in the animals was three times higher than that of BE.

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Additionally, levels of cocaine in muscle tissue were approximately three times greater compared to liver tissue, with female Brazilian sharpnose sharks showing higher drug concentrations in their muscle tissue than males, as per the study.

“The findings suggest that all sharks were exposed to cocaine within their natural habitats,” the authors stated.

Cocaine Use Soaring

The researchers pointed out that global cocaine use has significantly increased in recent decades, citing data from the United Nations World Drug Report 2023.

As per the report, around 4.8 million, equivalent to approximately 22 percent of the estimated 22 million cocaine users globally, are located in South America as of 2021, with Brazil emerging as the second-largest consumer market in the region.

“Indeed, in these regions, rising COC use rates align with insufficient sewage treatment infrastructure, where treatment rates are only at around 50 percent,” the researchers mentioned.

The study authors highlighted the potential consequences of having illicit drugs present in ecosystems, noting that cocaine is considered “pseudo-persistent” due to continuous environmental release from inadequate sewage treatment facilities and clandestine refining operations.

One of the reasons for the drug being detected in water bodies is also attributed to “drifting cocaine packs not retrieved by sellers or authorities,” which could become significant sources of cocaine in water and biota and potentially be consumed by larger fish, including sharks, the authors added.

Further research is essential to better comprehend how shark behavior may be influenced by consuming cocaine, the authors concluded.

“Understanding the absorption of drugs of abuse and other emerging contaminants in this species can provide valuable insights into human health risk assessments and the safety of seafood consumption,” they emphasized.