Scientists found drugs in the Gulf of Mexico dolphins

Scientists find traces of fentanyl and other drugs in the bodies of dolphins living in the Gulf of Mexico

The findings, published in iScience, underline the seriousness of the problem of ocean pollution and the impact of drugs on marine animals and the entire ecosystem^[1].

The study was launched in September 2020 when a team of marine biologists from Texas A&M University found a dead dolphin while monitoring the dolphin population in the Gulf of Mexico. The body of the small mammal was taken to the university for further study. A few years later, graduate student Makeyla Guinn became interested in analyzing dolphin tissues to study their hormones. As part of her plan, the biologist sucked out some fat from a dead dolphin she brought back. She used a non-targeted analysis method that allows her to identify all the chemical compounds in the tissue samples, including those that she had not originally planned to look for.

Among the thousands of hormonal compounds isolated in the analysis, the researchers found traces of the powerful drug fentanyl, a muscle relaxant and sedatives. This encouraged students and researchers to continue their research^[2].

Fentanyl is a synthetic opioid used to relieve extreme pain, but has a short duration of action. The drug is a potent µ-opioid receptor agonist. Historically, fentanyl has been used to relieve sudden and intense pain caused by a variety of diseases and as an analgesic prior to surgical procedures or as an anesthetic (in combination with benzodiazepine).

Fentanyl is approximately 100 times more potent than morphine and 50 times more potent than heroin. Fentanyl and other opioids are often used in combination with cocaine, heroin, and methamphetamine for intoxication. Between 2020 and 2021, 64,000 people in the US will die from overdoses of this drug.

Anya Ocampos, a student working on her dissertation, decided to delve deeper into this topic

She analyzed 89 dolphin tissue samples, 83 of which were taken from live individuals in the Madre Lagoon near the Texas coast. She found that fentanyl was the most abundant compound found, with traces in 24 samples. All 89 samples also contained at least one of the previously identified substances.

Interestingly, traces of the drug were even found in 2013 samples taken from dolphins in the Mississippi Sound, Dara Orbach, an associate professor of marine biology at Texas A&M University in Corpus Christi and co-author of the study, told ABC News. This shows that the problem of narcotic water contamination in the region has existed for more than a decade. Dolphins do not drink seawater but get their fluids from food, she said, so the presence of drug residues in their system suggests that their prey, fish and other marine organisms, may also be contaminated^[3].

The problem is clear, but what would be the solution?

The sources of contamination can be diverse. Possible causes include the dumping of drugs into the water near the Mexican border, agricultural runoff, spillages of contaminated liquids from production facilities and other effluents. For example, near the site of the dead dolphin found in 2020 is Robstown County, Texas, where the largest shipment of liquid fentanyl in US history was seized in 2023^[3].

Although the concentrations of the substances detected in the animals' bodies were low, their effects can be amplified by other stressors such as noise pollution, shipping, dredging, algal blooms, oil and chemical spills.

"These animals are constantly exposed to a wide range of negative stressors, and at some point their bodies become so vulnerable that they cannot cope," stressed Orbach.