Personal care ingredient may react with chlorine to produce carcinogen
consumers to significant quantities of chloroform, thought to be a
human carcinogen, said US researchers this week.
Peter Vikesland, assistant professor in civil and environmental engineering at Virginia Tech, has shown that when the chemical triclosan, present in many antimicrobial soaps and some moisturizers, reacts with chlorine in tap water, it produces chloroform which is classified by the Environmental Protection Agency (EPA) as a probable human carcinogen.
Triclosan is a synthetic antimicrobial agent, which is classified as a Class III drug by the Food and Drug Administration (FDA). As the result of its broad-spectrum bacteria-fighting ability, it has found increasingly popular use in personal care products, cosmetics, antimicrobial creams, acne treatments, lotions, hand soaps, and dish soaps. It is also sometimes used to preserve a product, including food.
The American Medical Association (AMA) has been urging the FDA to closely monitor and possibly regulate the home use of antimicrobials such as triclosan.
Past research has shown that chloroform is produced when free chlorine reacts with organic material.
"This is the first work that we know of that suggests that consumer products, such as antimicrobial soap, can produce significant quantities of chloroform," said Vikesland.
The implications of these reactions to consumers are not known however.
"There are numerous potential exposure pathways that can be envisioned, such as inhalation and skin exposure, when using antimicrobial soaps to wash dishes or when taking a shower. There is also risk of exposure when using triclosan laden moisturizers as they may also react with chlorine in the water," said Vikesland.
Vikesland and his associates have conducted research closely mimicking conditions found when washing dishes in the home. The results show that it is possible that the chloroform produced when the antimicrobial soap containing triclosan mixes with chlorinated water could be absorbed through skin or inhaled.
Vikesland's research is funded by the American Water Works Association Research Foundation (AWWARF) and by a National Science Foundation (NSF) graduate research fellowship to Krista Rule, the lead student on the project.
A report on Vikesland's work appears in the 6 April online edition of Environmental Science & Technology's ,a href="http://pubs.acs.org/subscribe/journals/esthag-w/2005/apr/science/kb_chlorine.html"target="_blank">science news.
