Wild sharks off the coast of Brazil have tested positive for cocaine, according to a new study by Brazilian scientists, the latest to show how human consumption of illegal drugs is harming marine life.
According to a study published in the journal Cocaine Sharks, Comprehensive Environmental ScienceScientists dissected the bodies of 13 sharpnose sharks (Rhizoprionodon larandiiA pike caught in a fisherman’s net off the coast of Rio de Janeiro.
All 13 tested positive for drugs.
Previous studies have found cocaine in rivers, oceans and sewage, and traces of the drug have been found in other marine organisms such as shrimp.
another study High levels of cocaine residues were recently found to be causing “severe toxic effects” in animals such as mussels, oysters and eels in the Bay of Santos, São Paulo state, Brazil.
But the concentrations found in the Rio sharks were 100 times higher than those found in other marine animals, the researchers said.
How the cocaine got into the shark’s body remains a mystery.
There are several possibilities. One is that the drugs fell into the sea during a transfer, or were dumped overboard by smugglers trying to evade authorities.
Brazil does not produce significant amounts of cocaine but it is a major exporter, with powerful street gangs such as the First Capital Command (PCC) sending tonnes of the drug by the container to Europe.
Another possible explanation is that the cocaine reached the ocean through sewage, and from there entered the sharks’ bodies.
“Although we cannot yet determine the source of the drugs, the results show that cocaine is widely trafficked and moved in Brazil,” said Enrico Mendes Saggiorno, research coordinator at the Oswaldo Cruz Institute.
“Cocaine has a short half-life in the environment, so finding it in these animals means that large amounts of the drug are getting into the biota,” he said.
“Other studies have found cocaine in rivers flowing into the ocean off the coast of Rio, but we were surprised to find it in sharks, and in such high concentrations,” Saggiolo said.
Another concern is that because the shark is commonly eaten in Brazil, cocaine residues could be transferred from the fish to humans.
“The extent to which this will affect humans remains unclear and will be the focus of future research, but in any case, this serves as a warning,” the researchers said.
