The drug could have entered the animals' bodies through smugglers
According to scientists, wild sharks off the coast of Brazil tested positive for cocaine. Recent studies show that illegal drug use by people harms marine life.
Wild sharks off the coast of Brazil tested positive for cocaine, according to a new study by Brazilian scientists. It's the latest study to show how human illicit drug use is harming marine life, The Guardian writes.
According to a study entitled «The Cocaine Shark» published in the journal Science of the Total Environment, scientists dissected the bodies of 13 sharpnose sharks (Rhizoprionodon lalandii) caught by fishermen in a net off the beach in Rio de Janeiro.
All 13 sharks tested positive for the drug, The Guardian notes.
Previous studies have found cocaine in river, sea and sewer water, and traces of the drug have also been found in other marine life such as shrimp.
A separate study recently found that high levels of cocaine residue caused “serious toxicological effects” in animals such as brown mussels, oysters and eels in Santos Bay in the Brazilian state of Sao Paulo.
But the concentration, found in Rio sharks was 100 times higher than in other marine animals, the researchers reported.
How cocaine ended up in sharks remains a mystery, notes The Guardian.
There are several theories: one is that the drug ended up at sea during a transshipment or was dumped by smugglers trying to evade authorities.
Brazil does not produce much cocaine, but is a major exporter, and influential Street gangs such as First Capital Command (PCC) ship tons of the drug in shipping containers to Europe, The Guardian highlights.
Another possible explanation is that the cocaine found its way into the sea via sewage, and then fell to the sharks.
“Regardless of where the drug came from — which is still impossible to determine — the results show that cocaine is widely sold and moved in Brazil,” said study coordinator Enrico Mendes Saggioro of the Oswaldo Cruz Institute.
“ Cocaine has a low half-life in the environment… so if we found it in an animal like this, it means a lot of drugs are getting into the biota,” the researcher comments.
“Others During my research, I had already found cocaine in the rivers that flow into the sea off the coast of Rio, but it was a surprise to me to find it in sharks — and in such large quantities,” Saggioro said.
Another problem is that that the sharpnose shark is a common part of the Brazilian diet, raising the possibility that cocaine residues could pass from fish to humans.
“We don't know what effect this might have on people and this should be a subject for future research. But in any case, this serves as a warning,” the researcher said.