Daily News Archives
From January 25, 2005
Chemical Found in U.S. Waterways
(Beyond Pesticides, January 25, 2005) Many rivers
and streams in the United States are believed to contain a toxic antimicrobial
chemical whose environmental fate was never thoroughly scrutinized despite
large-scale production and usage for almost half a century, according
to an analysis conducted by researchers at the Johns
Hopkins Bloomberg School of Public Health. The chemical, triclocarban,
has been widely used for decades in hand soaps and other cleaning products,
but rarely was monitored for or detected in the environment. The new
findings suggest that triclocarban contamination is greatly underreported.
The study is published in the current online edition of Environmental
Science & Technology, a peer-reviewed journal of the American
“We’ve been using triclocarban for almost half a century
at rates approaching 1 million pounds per year, but we have essentially
no idea of what exactly happens to the compound after we flush it down
the drain,” said the study’s lead author, Rolf U. Halden,
PhD, PE, assistant professor in the School’s Department of Environmental
Health Sciences and founding member of its Center for Water and Health.
The nationwide assessment of triclocarban contamination is based in
part on an analysis of water samples collected from rivers in and around
Baltimore, MD, as well as from local water filtration and wastewater
treatment plants. From the samples, Dr. Halden and his summer research
intern, Daniel H. Paull, now a graduate student in the Chemistry department
at Johns Hopkins University, observed the occurrence of triclocarban
in the environment correlated strongly with that of triclosan, another
commonly used antimicrobial chemical that has been studied in much greater
detail because it is more easily detectable. Using an empirical model
and published data on the environmental occurrence of triclosan, the
researchers predicted triclocarban concentrations for 85 U.S. streams.
The study results suggest that the antimicrobial contaminant is present
in 60 percent of the U.S. water resources investigated, thereby making
it the fifth most frequent contaminant among 96 pharmaceuticals, personal
care products and organic wastewater contaminants evaluated.
To determine the validity of the analysis, the researchers compared
their predicted nationwide levels of contamination to experimentally
measured concentrations in the Greater Baltimore region, and found no
statistically significant differences. The results also show that the
levels of triclocarban in water resources nationwide are much higher
than previously thought.
In surface water from the Baltimore region, the researchers detected
triclocarban at concentrations of up to 6.75 micrograms per liter (parts-per-billion).
This maximum concentration was 28-fold higher than previously reported
levels, which are currently used by the U.S. Environmental Protection
Agency for evaluation of the ecological and human health risks of triclocarban.
“Along with its chemical cousin triclosan, the antimicrobial compound
triclocarban should be added to the list of polychlorinated organic
compounds that deserve our attention due to unfavorable environmental
characteristics, which include long-term persistence and potential bioaccumulation.
Triclocarban, for example, has an estimated half-life of 1.5 years in
aquatic sediments. Do the potential benefits of antimicrobial products
outweigh their known environmental and human health risks? This is a
scientifically complex question consumers, knowingly or unknowingly,
answer to everyday in the checkout line of the grocery store,”
said Dr. Halden.
of Triclocarban and triclosan in U.S. Water Resources"
was written by Rolf U. Halden and Daniel H. Paull.
TAKE ACTION: When purchasing personal care
products such as deodorant, toothpaste and soap, always check the ingredient
listing and avoid those that contain triclosan and triclocarban. Write
to companies that use these toxic chemicals and demand safer products.
For more information on triclosan, see Beyond Pesticides’ triclosan
Factsheet, or contact