Sharks Off The Coast Of Brazil Test Positive For Cocaine

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“We were actually dumbfounded,” said Rachel Ann Hauser Davis, a co-author of the study and a biologist at the Oswaldo Cruz Foundation in Brazil. “We were excited in a bad way, but it’s a novel report. It’s the first time this data has ever been found for any top predator.”

However, it is important to note that the sample size was relatively small, leaving questions about the possible effects on the sharks themselves and on any predators that may consume them.

“I thought it was pretty remarkable that they got it published even with just 13 animals,” said Daniel Snow, the director of the Water Sciences Laboratory at the University of Nebraska, who did not participate in the research.

Dr. Snow was among the first researchers to measure an illicit drug, methamphetamine, in wastewater in Nebraska. “It’s not too big of a stretch to imagine that these chemicals that wind up in the water can affect aquatic organisms that live in that same water,” he said.

Dr. Hauser Davis said there were several hypotheses as to how cocaine found its way to the marine creatures, including illegal labs refining cocaine or cocaine packages lost or dumped by traffickers. However, she believes these account for only a small amount of the drug found in the ocean.

“We feel that the major source would be excretion through urine and feces from people using cocaine,” she said. Most wastewater treatment plants worldwide cannot effectively filter these substances, leading to their release into the ocean.

Tracy Fanara, an environmental engineer in Florida who led the research team for a 2023 documentary titled Cocaine Sharks, which served as an inspiration for the title of last week’s study, noted that the drug was still a small part of the larger problem of pollutants in natural habitats.

“Cocaine gets people interested,” she said. “But we have antibiotics, antidepressants, pharmaceuticals, sunscreen, insecticides, fertilizers. All of these chemicals are entering our ecosystem.”

Dr. Hauser Davis expressed similar concerns. “Why isn’t anyone surprised when you find metals, pesticides, and PFAS?” she said.

But she hopes their research will open new doors to testing other animals for cocaine.

“We’re hoping to do other sharks, rays, and even sea turtles.”