Pharmaceuticals have been finding their way into streams, rivers, and other surface waterways, and a new study says it’s due to a variety of factors.
To better understand the matter, the team of scientists from the United States Geological Survey examined streams with and without wastewater plants located on them. Streams considered “wadeable” were targeted by the study.
Sewage Plants Not the Only Culprit
The researchers, to correct an information gap, sought to uncover “information about pharmaceutical occurrence, distribution, primary sources, and spatial and temporal variability” for “wadeable headwater stream reaches” on which there are most often no wastewater treatment facilities.
Scientists determined that urban run-off and below-surface water movement could play a role in distributing the unwelcome substances.
Although wastewater treatment plants are commonly implicated in the presence of these types of pharmaceutical contaminants, the researchers say that they detected substances at 71 percent of the sites without any National Pollutant Discharge Elimination System discharges (this type of discharge falls under a permit required by the U.S. Environmental Protection Agency). According to the study, this clearly demonstrates that wastewater treatment plants are not the sole source of such substances, and emphasizes “the need for whole-watershed mitigation approaches.”
Wide Range of Contaminants in Water
In 2014, samples were gathered from 59 streams in four states in the Southeastern U.S. The samples were taken varying distances from wastewater treatment plants. Samples were tested for 108 pharmaceuticals and related substances, some of which are known to cause genetic changes in fish and other aquatic life.
One in particular is metformin, a drug used to treat diabetes, which has reportedly been found in treated wastewater, in surface water sources, and in tap water. It was detected in 89 percent of the water samples and at 97 percent of the sites.
The researchers found at least one pharmaceutical at every site, while several were detected at roughly 10 percent of all of the sites in “concentrations reported to affect multiple aquatic end points.”
Other prevalent substances included nicotine-related compounds, caffeine-related compounds, acetaminophen, the anti-seizure medicine carbamazepine, the antihistamine fexofenadine, lidocaine, the muscle relaxant methocarbamol, pseudoephedrine/ephedrine, the antibiotic sulfamethoxazole, and tramadol, an opioid pain medication.
Other Watersheds Studied
This type of watershed investigation is becoming more commonplace. Washington State’s Puget Sound was studied by NOAA’s Northwest Fisheries Science Center in Seattle, which found 81 substances — including Prozac, Advil, Benadryl, Lipitor, caffeine, and cocaine — in the juvenile Chinook salmon they studied. They also found personal-care products such as the antibacterical chemical Triclosan in the outfall of sewage treatment plants flowing into the sound.
Pharmaceutical wastes and other contaminants of emerging concern are causing unknown impacts on aquatic life and water quality worldwide, which some scientists have said makes additional research into this issue essential.
A 2013 study of streams of similar sizes in New York, Maryland, and Indiana, looked at six pharmaceutical compounds and the stream’s relative health. Scientists concluded that most sewage treatment facilities are not equipped to fully remove pharmaceuticals before treated water is discharged into surface water.
What Can We Do About It?
Reverse osmosis can remove an estimated 99 percent of contaminants from wastewater streams, including “large pharmaceutical molecules,” according to the World Health Organization. It and other organizations are attempting to educate consumers on the importance of the proper disposal of medications, both over-the-counter and prescription. In some areas there are drug take-back programs for consumers.
This growing body of research is aimed at improving wastewater management protocols and treatment technologies, as well as consumer education.
The full article — “Metformin and Other Pharmaceuticals Widespread in Wadeable Streams of the Southeastern United States” was published in the journal Environmental Science & Technology Letters.