New Study Led by Bard Biology Professor Finds that Even Small Concentrations of Triclosan Could Have Long-Lasting Impact on Bacterial Diversity in Freshwater StreamsANNANDALE-ON-HUDSON, N.Y.— Triclosan is a synthetic antimicrobial agent used extensively for more than 40 years in clinical settings and in personal care products such as soap and toothpaste. Its widespread use has resulted in low levels of triclosan being detected in freshwater streams, including the Hudson River. While the effects of triclosan on microbial communities found in soil and sediments is well documented, little is known regarding the possible effects of triclosan on microbial communities in freshwater streams as it is released from sediments or treated wastewater outflows. A new study led by Bard College Assistant Professor of Biology Gabriel Perron shows that even small concentrations of triclosan commonly found in streams can disrupt freshwater microbial communities in favor of bacteria that are associated with human disease and antibiotic resistance. In the study, “Triclosan Alters Microbial Communities in Freshwater Microcosms,” published in Water, Perron and collaborator M. Elias Dueker, assistant professor of environmental and urban studies—both faculty of the Bard Center for the Study of Land, Air, and Water—contend that understanding the impact of triclosan on these microbial populations is crucial from a public health perspective because of people’s frequent recreational exposure to freshwater lakes, streams, and rivers.
Using water samples from collected from the Saw Kill—a freshwater tributary of the Hudson River that flows through the towns of Milan, Red Hook, and Rhinebeck, New York—Perron, Dueker, and Bard students Alexandra Clarke ’16 and Daniella Azulai ’17, along with Michiel Vos from the European Center for Environmental and Human Health at the University of Exeter in Truro, UK., established experimental microcosms in their laboratory where they could monitor the evolution of microbial communities growing in the presence of small concentration of triclosan. Investigating the whole microbial communities using DNA sequencing, Perron and colleagues were able to track minute changes in microbial composition and observe the growth of potentially dangerous pathogenic bacteria.
“Even though the use of triclosan is slowly being regulated in most developed countries, our study shows that we are likely to see the lasting impacts of triclosan on our streams given the long half-life of the antimicrobial in the environment,” says Perron. “Not only does triclosan have the potential to increase the abundance of human pathogens in our streams, but it could also disrupt the important ecological functions carried out by our freshwater ecosystems, such as wetlands and aquifers.”
To read the full study, click here. For more information on the Bard Center for the Study of Land, Air, and Water, please visit landairwater.bard.edu.
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