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Sharks living off the coast of Brazil have tested positive for cocaine, according to new research, the first time that the drug has been detected in free-ranging sharks.
Scientists tested 13 Brazilian sharpnose sharks in the waters off the city of Rio de Janeiro and found cocaine present in both the liver and muscle tissue of all 13 specimens, according to a paper by researchers at the Oswaldo Cruz Foundation in Brazil sent to CNN on Tuesday.
The species was chosen due to its small size and the fact that it lives in a small area of coastal waters, where it is exposed to significant contaminant discharges for its entire life cycle, according to the study.
Cocaine levels were around three times higher in muscle tissue than liver tissue, according to the study, while female sharks had higher cocaine concentrations in muscle tissue compared to males.
Cocaine pollutes the sea due to sewage discharges from humans who use the drug, as well as the illegal laboratories that produce it, study co-author Enrico Mendes Saggioro, an ecotoxicologist at the foundation, told CNN on Tuesday.
Cocaine consumption has risen massively around the world in recent decades, according to the study.
Around 22% of users live in South America, the paper added, with Brazil the second largest consumer market in the region. Increased consumption and poor sewage treatment infrastructure has made for increased cocaine levels in the sea, say researchers.
