Dr. Laura Johnson, the director of 海外吃瓜鈥檚 National Center for Water Quality Research, led new Ohio Sea Grant research that measured veterinary antibiotics in Lake Erie tributaries.
The research found that some medications are indeed prevalent in regional watersheds at low concentrations.
鈥淲e wanted to better understand if we鈥檙e still seeing veterinary medicines in streams and rivers, how prevalent they are, and if we should be concerned about it,鈥 Laura said.
About 1.2 million kilograms of antibiotics are produced for U.S. agriculture each year, and about 90 percent of those veterinary antibiotics can be excreted by livestock unmetabolized. Once in the environment, antibiotics can contribute to the phenomenon known as antibiotic resistance, in which bacteria adapt to overcome the drugs designed to eliminate them.
鈥淚f we have antibiotic resistance for bacteria that would also affect humans, that would be a problem,鈥 Laura said. 鈥淎nd if you think about it from an ecological standpoint, having more antibiotics means that you鈥檙e changing the microbial community structure of an aquatic ecosystem. That can just change who it鈥檚 functioning in general.鈥
To find out whether this is a concern in the western basin of Lake Erie, Laura鈥檚 team measured pharmaceuticals at trace levels in the Sandusky and Maumee River watersheds. The 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鈥檚 Water Science Laboratory for extraction and analysis.
Ultimately the researchers found that some antibiotics, both veterinary and human, were frequently detected in rivers and streams in the Western Basis. The team also confirmed that across watersheds, antibiotic levels were associated with the density of livestock nearby.
Laura said that the levels of these antibiotics are relatively low 鈥 low enough that they鈥檙e 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 the state and regulatory bodies such as the Ohio Environmental Protection Agency and the Ohio Department of Health.
鈥淜nowing the potential for exposure to antibiotics in the environment is useful, even if the levels weren鈥檛 incredibly high,鈥 Laura explained. 鈥淗opefully results like this would encourage farmers and producers to not use antibiotics as often. I think anybody would agree that if there鈥檚 a sick animal or other issues, yes, use antibiotics, but use them smartly.鈥
Ohio Sea Grant is supported by The Ohio State University College of Food, Agricultural, and Environmental Sciences School of Environment and Natural Resources, OSU Extension and NOAA Sea Grant.