Study reveals presence of fentanyl in Gulf of Mexico dolphins

A team of faculty and student researchers at Texas A&M University-Corpus Christi (TAMU-CC), in partnership with the National Oceanic and Atmospheric Administration and Precision Toxicological Consultancy, have detected traces of human pharmaceuticals in the blubber of live, free-swimming common bottlenose dolphins in the Gulf of Mexico. Dolphins, like humans, consume fish and shrimp, suggesting potential human health impacts.

“Pharmaceutical drugs are therapeutic substances used in human and veterinary medicine to diagnose, treat, cure, or prevent disease,” said Dr. Dara Orbach, Assistant Professor of Marine Biology at TAMU-CC and Principal Investigator on the project.

“Yet, improper use of pharmaceuticals can cause harmful effects including antibiotic resistance, addiction, overdose, and mortality. Furthermore, pharmaceuticals have become emerging micropollutants and are a growing global concern as their presence has been reported in freshwater ecosystems, rivers, and oceans worldwide.”

The study, “Pharmaceuticals in the Blubber of Live Free-Swimming Common Bottlenose Dolphins,” published in the journal iScience, analyzed 89 dolphin blubber samples, including 83 collected through live-animal biopsy and six from deceased dolphins.

Pharmaceuticals were found in 30 of the dolphins. Fentanyl, an opioid analgesic for severe pain that is 100 times more potent than morphine, was present in 18 of the biopsied animals and in all post-mortem dolphins.

The team selected dolphins from three sites around the Gulf of Mexico, including Redfish Bay and the Laguna Madre in Texas, along with 12 historic dolphin tissue samples from the Mississippi Sound collected in 2013.

“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,” Orbach said.

“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.”

Tissue samples from dolphins residing in areas with high threat risks, such as oil spills, vessel traffic, and algal blooms, showed higher levels of pharmaceutical contamination.

“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.”