The study looked at freshwater bodies in Minnesota and focused on antimicrobial soaps, disinfectants, and sanitizers used to scrub hands clean of bacteria and discovered that the active ingredient triclocarban may be more worrisome than it’s often cited cousin, triclosan.
According to the study researchers, the active ingredients in these products can be traced from the home to sewers, then on the wastewater treatment plants, and ultimately downstream bodies of water.
"This study underscores the extent to which additives of antimicrobial consumer products are polluting freshwater environments in the US; it also shows natural degradation processes to be too slow to counter the continuous environmental release of these endocrine disrupting chemicals," said Halden, director of Environmental Security at the Biodesign Institute and professor in the Ira A. Fulton School of Sustainable Engineering and the Built Environment.
Triclocarban pollution found to be far higher than triclosan
The ASU study analyzed river, creek and lakebed sediment samples from 12 locations both upstream and downstream from wastewater treatment plants for the presence of antimicrobial compounds
The research focused on two active ingredients found in antibacterical soap, triclosan and triclocarban, which are thought to be slow to degrade in the environment, and are most frequently found in both personal care care and pharmaceutical products.
Interestingly, the results showed that overall concentrations of triclocarban were 3- to 58-times higher than those of the more frequently monitored triclosan.
"We were able to detect these two compounds both upstream and downstream of suspected input sources, and the levels of the antimicrobial soap ingredient triclocarban were usually higher compared to triclosan," said study author Arjun Venkatesan.
"Although triclosan is used in a larger number of formulations and personal care products, we found triclocarban to be more abundant in freshwater environments."
Presence of antimicrobial compounds found both upstream and downstream
Venkatesan also pointed to the fact the study had found detectable levels of the antibacterial ingredients were found both upstream and downstream of the wastewater plants, defying expectations that pollution would be far more prevalent downstream.
"Regulatory agencies are aware of the overuse of antimicrobials but no state or federal restrictions have been implemented yet for either triclosan or triclocarban," said Halden.
"Aside from ecological concerns, widespread environmental occurrence of antimicrobials also is a potential public health concern because unwarranted use of antimicrobials can promote drug resistance of human pathogens."
Ref: A.K. Venkatesan, et al., Occurrence of triclosan, triclocarban, and its lesser chlorinated congeners in Minnesota freshwater sediments collected near wastewater treatment plants, J. Hazard. Mater. (2012), Vol. 229-230