Illegal drugs harming stream aquatic ecosystems
As if toxic waste from chemical manufacturing and other industrial processes weren’t enough, scientists say some streams are also being fouled by remnants of amphetamines — in some cases at high enough levels to alter the base of aquatic food chain.
A new study, published in the journal Environmental Science & Technology, traced the presence of illicit drugs at six stream sites around Baltimore, focusing on the Gwynns Falls watershed, which is part of the Baltimore Ecosystem Study Long-Term Ecological Research program. Two rural streams were also sampled in the Oregon Ridge watershed, the closest forested region.
“Around the world, treated and untreated wastewater entering surface waters contains pharmaceuticals and illicit drugs that originate from human consumption and excretion, manufacturing processes, or improper disposal,” said lead author Sylvia S. Lee conducted the work as a postdoctoral researcher at the Cary Institute of Ecosystem Studies. “We were interested in revealing how amphetamine exposure influences the small plants and animals that play a large role in regulating the health of streams,” said Lee, now with the EPA.
After sampling the streams, the researchers followed up with a lab experiments to determine how amphetamine affects stream life.
In recent years, there has been an increase in the use of amphetamine medications in the treatment of conditions like attention-deficit hyperactivity disorder. At the same time, stimulants like methamphetamine, ecstasy, and cocaine are also used illicitly.
“We have every reason to suspect that the release of stimulants to aquatic environments is on the rise across the globe, yet little is known about the ecological consequences of this pollution,” said co-author Emma J. Rosi-Marshall, a freshwater ecologist at the Cary Institute.
When the artificial streams were exposed to amphetamine at a concentration similar to levels found in parts of the Gwynns Falls watershed, there were “measurable and concerning effects to the base of the aquatic food web,” she said.
Among their findings: in streams with the amphetamine addition, the growth of biofilms was significantly suppressed, the composition of bacterial and diatom communities changed, and aquatic insects emerged earlier.
“As society continues to grapple with aging wastewater infrastructure and escalating pharmaceutical and illicit drug use, we need to consider collateral damages to our freshwater resources,” Rosi-Marshall said. “More work is needed on the ecological fate of these pollutants and the threat they pose to aquatic life and water quality. Ultimately, solutions will lie in innovations in the way we manage wastewater.”