Pharmaceutical compounds and their metabolites or degradation products commonly reach waterways when they are flushed as human waste and survive wastewater treatment. A new study demonstrates that these contaminants released from sources such as sewer overflows, septic fields, and storm water runoff also contribute to the widespread distribution of pharmaceuticals in the environment (Environ. Sci. Technol. Lett. 2016, DOI: 10.1021/acs.estlett.6b00170).
A U.S. Geological Survey team led by hydrologist Paul M. Bradley sampled 59 headwater streams, most without wastewater treatment plants, in an area of the southeastern U.S. stretching from Alabama to Virginia. The team used liquid chromatography/mass spectrometry to look for a set of 108 pharmaceuticals in the water samples.
The team detected up to 45 compounds at each test site, with a median of six detected. Cumulative concentrations at each site ranged from 17 to 16,000 ng/L. Several individual compounds were detected at concentrations that would affect multiple aquatic species. “Pharmaceuticals are designed to be bioactive,” Bradley notes.
One compound that was particularly prevalent was metformin, which is used to treat type 2 diabetes. Bradley and colleagues found metformin in water taken from 97% of the test sites.
“It illustrates the connection between human health and environmental health,” Bradley says. “Type 2 diabetes can be prevented by adjusting one’s behavior or treated with drugs. But if you’re using metformin to treat it, you’re also treating the environment.”