The idea that the behaviors of humans end up in the water and impact our ecosystems and endangered species is an important one to keep in mind. Much like we share a water supply, we also share a drug supply.
European eel by Lorenz-Seebauer via Wikimedia Commons (CC BY-SA
4.0)
This summer many media outlets smelled blood in the water and went
on a feeding frenzy, publishing sensationalized reports about sharks
getting high on cocaine off the coast of Florida.
The story originated with a Discovery Channel “Shark Week” program,
which posited that odd, manic shark behavior observed off the
Florida Keys originated after the predators consumed bales of
cocaine dropped in the water by smugglers.
Shark scientists quickly debunked this theory by pointing out that
sharks would only be attracted to cocaine if it smelled like meat,
and that cocaine has never been found in wild sharks’ systems.
Still, the damage was done: The media had drummed up one more excuse
to be afraid of sharks.
But cocaine in the water — that’s something we should still be
afraid of. Only it’s not coming from bales of drugs dropped from the
sky. It’s coming from human urine, the same way antidepressants and
other pharmaceuticals end up in our sewers and waterways.
And it’s not causing the animals who consume it to get high or
stoned. New research published in the journal Fishes reveals that
this human-excreted cocaine could cause a host of health problems
for wildlife — and people.
Cocaine’s a Hell of a Drug
To understand this potential threat, researchers looked to the
critically endangered European eel (Anguilla anguilla), a species
known to science for its usefulness in studying environmental
pollutants.
“Eels are excellent biomonitors,” says Anna Capaldo, a biology
professor at the University of Naples Federico II and the study’s
senior author. “They are very sensitive to aquatic contaminants,
live in the same place for many years, and have a large percentage
of fat that promotes the accumulation of many contaminants. They
also represent a source of food for humans.”
Eels regularly swim in waterways where cocaine has been detected,
like the Thames River in London. Previous studies have detected the
drug in eels’ systems, but Capaldo and her team wanted to find out
exactly what that meant. They exposed young eels to levels of
cocaine equivalent to those found in the environment (20 ng/L−1) for
30-50 days. (All experiments were conducted under ethical guidelines
for animal experimentation.)
The result: The cocaine accumulated at various levels in — and
caused damage to — the eels’ brains, muscles, livers, kidneys,
digestive tracts, gills, skin, spleens and gonads.
“That cocaine could cause damage to a living organism, such as an
eel, was somewhat predictable,” Capaldo says. “However, the fact
that this damage was also induced by a chronic exposure to very low
concentrations of cocaine (20 ng of cocaine per liter of water
equals 20 billionths of a gram of cocaine per liter) surprised us.”
The study concluded that even this relatively low concentration of
cocaine could put European eels further at risk in the wild. “[T]he
alterations in nervous and endocrine systems, and in peripheral
tissues, induced by cocaine, could decrease its ability to survive
and its reproductive fitness,” the authors wrote. “Moreover, the
presence of cocaine in the muscle, which is the edible part of the
animal, can be a problem not only for the eel, which needs a healthy
muscle to complete reproductive migration, but also for human
consumption of this fish.”
As for the “Cocaine Shark” effect? That remains to be seen.
“Drugs are particularly dangerous because they affect mood and
behavior of living organisms, and this in turn can interfere with
their survival skills,” Capaldo says. “In this regard, there are
many studies concerning the effects of antidepressants on behavior
of aquatic fauna. The effects of cocaine on eels’ behavior are a
topic that we’d like to explore with further studies.”
They also hope to repeat the study using more than one contaminant,
so they can better understand the compound effect of multiple
pollutants or drugs on animals’ health.
The eels in this study were actually lucky. They were weaned off the
cocaine, and many of the health effects receded. But eels
encountering illicit drugs in the wild would remain exposed to
environmental cocaine throughout their time in a polluted habitat —
a situation that’s likely to worsen as the world gets hotter.
The Climate-Cocaine Connection
Capaldo points out that pharmaceuticals and illicit drugs are just
one threat to European eels; climate change poses a danger to all
eel species across the world. But the two threats remain linked, as
temperature fluctuations can cause chemical interactions to change
and become more toxic.
“All these findings would suggest that climate change, and in
particular the rise in temperatures, could pose a problem for eels’
survival,” she says.
Meanwhile the study cites research that points out how cocaine poses
its own threat to the climate — and a major one, at that:
“It is estimated that 1982 tons of pure cocaine were produced in 2020, an increase of 11% over the previous year. The carbon footprint … of cocaine, related to cultivation of coca plants, processing of cocaine, disposal of waste generated in the manufacturing process and land-use change, is 4500 kg CO2e per kg of cocaine produced. Therefore, referring to the 2020 data, we obtain a mean value of the total emissions per year of 1.9 million tons of CO2e, a value significantly higher than that of other crops, as sugar cane or cocoa beans.”
And the problem is only going to get worse. Cocaine production
increased another 35% between 2021 and 2022, according to a recent
United Nations report. Meanwhile a commentary published this July in
the Journal of Addiction Medicine predicts that climate change — and
its resulting human suffering — will worsen the opioid epidemic and
increase abuse of fentanyl, cocaine, and other legal and illegal
stimulants.
Which just goes to show: It’s all connected.
“We are all linked by our environment,” says Dr. Emily Einstein,
chief of the Science Policy Branch at the National Institute on Drug
Abuse, who was not affiliated with either study. “The idea that the
behaviors of humans end up in the water and impact our ecosystems
and endangered species is an important one to keep in mind. Much
like we share a water supply, we also share a drug supply. I think
this idea that humanity is kind of linked by these shared resources
is an important one to remember. We all have to care about each
other, the impact we’re having on each other, and on our environment
as well.”