TIFFIN, Ohio — New Ohio Sea Grant research measured veterinary antibiotics in Lake Erie tributaries and found that some medications are prevalent in regional watersheds at low concentrations.
About 1.2 million kilograms of antibiotics are produced for U.S. agriculture each year and up to 90% of those veterinary antibiotics can be excreted by livestock, unmetabolized. Once in the environment, antibiotics can contribute to the phenomenon known as antibiotic resistance — when bacteria adapt to overcome the drugs designed to eliminate them.
To find out whether this is a concern in the western basin of Lake Erie, Dr. Laura Johnson, director of the National Center for Water Quality Research at Heidelberg University, and her team measured pharmaceuticals at trace levels in the Sandusky and Maumee River watersheds. Researchers used passive samplers at various points across the watersheds over time at very low concentrations. Once collected, the samples were sent to the University of Nebraska-Lincoln’s Water Science Laboratory for extraction and analysis.
Ultimately, researchers found that some antibiotics, both veterinary and human, were frequently detected in rivers and streams in the western basin. The team also confirmed that across watersheds, antibiotic levels were associated with the density of livestock nearby.
Johnson said that the levels of these antibiotics are relatively low — low enough that they’re likely not causing antibiotic resistance in the microbial environment of streams and rivers. However, their widespread detection could suggest that antibiotics are being applied to land at high concentrations, meaning that antibiotic resistance could still be a concern.
Results from the study will inform livestock practices in state and regulatory bodies such as the Ohio Environmental Protection Agency and Ohio Department of Health.
