Streams Polluted By Pharmaceutical Waste
April 1, 2013

Streams Polluted By Pharmaceutical Waste

Lee Rannals for — Your Universe Online

Researchers wrote in the journal Ecological Applications that pharmaceuticals commonly found in the environment are disrupting streams.

The latest research highlights the ecological cost of pharmaceutical waste and the need for more research into environmental impacts.

"Pharmaceutical pollution is now detected in waters throughout the world. Causes include aging infrastructure, sewage overflows, and agricultural runoff," said lead author Dr. Emma Rosi-Marshall, a scientist at the Cary Institute of Ecosystem Studies. "Even when waste water makes it to sewage treatment facilities, they aren't equipped to remove pharmaceuticals. As a result, our streams and rivers are exposed to a cocktail of synthetic compounds, from stimulants and antibiotics to analgesics and antihistamines."

With researchers from Indiana University and Loyola University Chicago, Rosi-Marshall looked at six common pharmaceuticals, including caffeine, the antibiotic ciprofloxacin, the antidiabetic metformin, two antihistimines used to treat heartburn (cimetidine and ranitidine), and one antihistamine used to treat allergies for the study.

"We focused on the response of biofilms — which most people know as the slippery coating on stream rocks — because they're vital to stream health," Rosi-Marshall said "They might not look like much to the naked eye, but biofilms are complex communities composed of algae, fungi, and bacteria all living and working together. In streams, biofilms contribute to water quality by recycling nutrients and organic matter. They're also a major food source for invertebrates that, in turn, feed larger animals like fish."

The team found diphenhydramine had negative effects on algae production and microbial respiration. Exposure caused biofilms to experience up to a 99 percent decrease in photosynthesis. The antihistamine also caused a change in the bacterial species present in the biofilms, including an increase in a bacterial group known to degrade toxic compounds and a reduction in a group that digests compounds.

"We know that diphenhydramine is commonly found in the environment. And its effect on biofilms could have repercussions for animals in stream food webs, like insects and fish," Rosi-Marshall said. "We need additional studies looking at the concentrations that cause ecosystem disruption, and how they react with other stressors, such as excess nutrients."

Researchers developed a new model for determining the environmental effects of pharmaceutical products in 2011. The team from the Autonomous University of Barcelona (UAB) developed a new tool to effectively predict what will happen to current and future pharmaceutical products. They found a variety of drugs that could be harmful to wildlife end up in the environment.

The study, published in Water, Air, & Soil Pollution, helps evaluate the environmental risks of current drugs and those that may be marketed in the future.