Microbial degradation of triclosan within wastewater treatment plants

Sarah Gollwitzer, The College of Wooster


There are a number of common chemical contaminants released into the environment through wastewater treatment plants (WWTPs) that have recently been found to be an area of concern. One of these contaminants is triclosan (TCS), a common antibacterial that is found in many soap products. Triclosan has been found to be present in both effluent and biosolids from WWTPs. It then reaches the environment when effluent is used for irrigation or is released into streams and when biosolids are applied as fertilizer for crops. It has been found that triclosan can be mildly toxic to fish in the environment, and two of triclosan's degradates can be dangerous as well; methyl triclosan easily builds up in an organism's system and is mildly toxic to fish, and dioxins are carcinogenic. These degradates are potentially being formed within the WWTPs and being introduced into the environment. This senior IS research looked specifically at the biological (microbial) step of WWTPs and the breakdown of triclosan. The focus was on whether or not the microbes degrade triclosan, and if they do at what rate and into what degradate compounds. Microcosms of sludge samples were made, spiked with triclosan, and grown for specific lengths of time to determine the pattern of triclosan break down. Analysis was done using liquid chromatography/mass spectrometry (LC/MS) along with other analytical chemistry techniques. The results supported the conclusion that if degradation was occurring it was not until after at least 28 days.


© Copyright 2009 Sarah Gollwitzer