The opioid fentanyl has made its presence known in an unexpected place — the blubber of dolphins in the Gulf of Mexico. In a concerning study, researchers detected fentanyl in 27% of analyzed dolphins, linking this potent drug to human-induced pollution in marine ecosystems.

Fentanyl, a synthetic opioid up to 100 times more potent than morphine, is a lifesaver for managing severe pain. However, it’s become a key actor in the escalating opioid crisis that has devastated communities in the US and abroad. Overdose deaths involving fentanyl have surged and show no sign of slowing down — currently, fentanyl is the deadliest drug in the US.

In the new study, a team of researchers and students from Texas A&M University and NOAA analyzed 89 common bottlenose dolphin blubber samples, including 83 collected through live-animal biopsy.

The team found pharmaceuticals such as fentanyl, carisoprodol, and meprobamate in the fat reserves of these dolphins. Overall, pharmaceuticals were found in 30 of the dolphins, and fentanyl in 24 of them.

Why this is so concerning

Dolphins, as apex predators, act as barometers for the marine environment. Their blubber, rich in lipids, not only provides energy but also acts as a reservoir for persistent contaminants. These findings, emerging from advanced chemical analyses, show that dangerous pharmaceuticals are widespread throughout the ecosystems.

“Dolphins are often used as bioindicators of ecosystem health in contaminant research due to their lipid-rich blubber that can store contaminants and be sampled relatively minimally invasively in live animals,” said Dr. Dara Orbach, Assistant Professor of Marine Biology and lead author of the study.”

Orbach also says this is not something that just happened, it’s something that’s been going on for a while.

“We did find one dead dolphin in Baffin Bay in South Texas within one year of the largest liquid fentanyl drug bust in US history in the adjacent county. And the Mississippi dolphins comprised 40% of our total pharmaceutical detections, which leads us to believe this is a long-standing issue in the marine environment.”

Researchers also mention that tissues from dolphins residing in areas closer to vessel traffic and oil spills showed higher levels of pharmaceutical contamination.

How bad is it for ecosystems?

In humans, fentanyl binds to opioid receptors in the brain, significantly altering pain perception and neural activity. While the exact impact on dolphins remains unclear, it’s very likely that it disrupts their behavioral and physiological abilities.

Such disruptions could affect their ability to reproduce, hunt, and navigate, cascading down the food web and altering predator-prey dynamics. Chronic exposure might weaken immune systems or disrupt hormonal balances, leaving dolphins vulnerable to disease and environmental stressors. Given their role as top predators, such effects could ripple through the marine food web, altering ecosystem dynamics.

As a highly potent opioid, fentanyl can accumulate in predators like dolphins, but other creatures (like fish or invertebrates) may also be affected. Unlike some contaminants that degrade quickly, fentanyl persists, posing long-term risks to marine species.

Furthermore, the presence of fentanyl in marine ecosystems is more than a wildlife issue — it’s a public health concern. Humans, too, are part of the food web. The Gulf of Mexico supports a multi-billion-dollar seafood industry — and contaminated fish and seafood can reintroduce fentanyl and other pharmaceuticals into human diets, raising potential health risks. Addressing fentanyl contamination isn’t just about saving dolphins — it’s about protecting entire ecosystems and livelihoods.

Chronic exposure to pharmaceuticals and their cumulative effects on marine mammals are not yet fully understood, yet their presence in three dolphin populations across the Gulf of Mexico underscores the need for large-scale studies to assess the extent and sources of contamination,” Orbach said.

“Our research team emphasizes the need for proactive monitoring of emerging contaminants, especially in regions with large human populations and major fishing or aquaculture industries.”

Where’s the Fentanyl coming from?

The research doesn’t definitively pinpoint the exact sources of the fentanyl found in the dolphins’ blubber, but it suggests possible pathways for contamination. Two potential sources for contamination stand out: wastewater and drug transport.

The study mentions the proximity of one sampling location to a significant fentanyl drug bust in the adjacent county. This raises the possibility of localized sources, such as illicit drug manufacturing or improper disposal of pharmaceuticals. It could be drug transports leaking into the water, illegal manufacturing facilities, or simply people’s urine.

To solve this problem, researchers suggest upgrading wastewater treatment facilities to target and remove pharmaceuticals. This isn’t just about fentanyl, but about other drugs that shouldn’t end up in water. Regulatory frameworks must enforce stricter controls on pharmaceutical waste, especially in regions with dense populations and heavy drug use.

Ultimately, the bigger challenge is reducing fentanyl consumption.

That, however, is something that won’t be easy at all.

Journal Reference: Anya Isabelle Ocampos et al, Pharmaceuticals in the Blubber of Live Free-Swimming Common Bottlenose Dolphins (Tursiops truncatus), iScience (2024). DOI: 10.1016/j.isci.2024.111507