A November 20 Sustainable Cities Network article reports on a study finding that a common antibacterial agent is leading to the creation of resistant bacteria in streams and rivers, with the problem being acute in more urban areas.  The article states that triclosan is currently found in around half of liquid soaps and also in toothpastes, deodorants, cosmetics, liquid cleansers, and detergents.  The chemical is entering waterways through wastewater and sewer systems.  Systems that utilize combined sewer overflows are particularly vulnerable.

Emma Rosi-Marshall, one of the paper’s authors and an aquatic ecologist at the Cary Institute of Ecosystem Studies in Millbrook, explains: “The bacterial resistance caused by triclosan has real environmental consequences. Not only does it disrupt aquatic life by changing native bacterial communities, but it’s linked to the rise of resistant bacteria that could diminish the usefulness of important antibiotics.”  …

Urbanization was correlated with a rise in both triclosan concentrations in sediments and the proportion of bottom-dwelling bacteria resistant to triclosan. A woodland creek had the lowest levels of triclosan-resistant bacteria, while a site on [Chicago’s] North Shore Channel downstream of 25 combined sewer overflows had the highest levels.

The report also supports prior research that wastewater treatment plants should be able to remove or reduce triclosan from wastewater.

A copy of the study can be purchased here.