A startling discovery has emerged off the coast of Rio de Janeiro, Brazil, where sharks have tested positive for cocaine.
According to a study published in Science of the Total Environment, the presence of cocaine in these sharks is linked to ongoing releases of the drug from inadequate sewage treatment systems and illegal refining operations.
Researchers from the Oswaldo Cruz Foundation analyzed 13 Brazilian sharpnose shark specimens collected between September 2021 and August 2023, finding traces of cocaine in both their muscle and liver tissues.
Biologist Rachel Ann Hauser-Davis stressed the need for further research to understand the full impact of this contamination on the sharks, noting that cocaine exposure could affect their growth, maturation, and possibly even their fertility, given the liver’s role in embryo development.
As apex predators, sharks are considered “sentinel species” that can offer early warnings about environmental threats to humans. The study underscores the importance of monitoring pollution’s effects on marine life.
While this research did not investigate the specific impacts of cocaine on sharks, other studies have shown that pollutants, such as methamphetamine, can lead to addiction in brown trout.
Additionally, various pollutants, including antidepressants, heavy metals, and birth control medications, have been found contaminating rivers, lakes, and oceans worldwide.
