Washing dishes can be bad for your health

Posted on June, 15 2005

Most people find washing dishes at home a chore, but new evidence has shown that it could have other more unpleasant effects.
Most people find washing dishes at home a chore, but new evidence has shown that it could have other more unpleasant effects.

Scientific research carried out in the United States have found that when dishwashing liquid containing triclosan, an anti-bacterial agent, was mixed with chlorinated tap water it produced significant quantities of chloroform*

Chloroform has been classed as a probable human carcinogen by the US Environmental Protection Agency, and according to the scientists at Virginia Polytechnic, USA, who carried out the research, "The presence of trihalomethanes such as chloroform in drinking water has been linked with human bladder cancers and miscarriages".
Triclosan has been on the market for more than 30 years, used as an anti-bacterial agent in cosmetics, personal care products (toothpastes, acne creams, deodorants, lotions) and hand and dishwashing soaps. It is also incorporated into a wide range of plastic consumer goods, including kitchenware and chopping boards. Its popularity stems from the fact that it stays on skin or surfaces, providing long-lasting action against germs. 

Unfortunately, it also stays in the human body and the environment. Triclosan is bioaccumulative and it has been found in human breast milk, and one of its variations, Methyltriclosan (formed by the biodegradation of triclosan in sewage treatment works), has also been accumulating in fish from Swiss Lakes.
While researchers had known that chlorine could react with compounds like triclosan to produce chloroform, noone had proved until now that this could happen in a domestic setting. By mimicking the conditions under which dishes would be washed at home – such as water temperature and concentration of chlorine -, it was found that chloroform could be produced and absorbed through the skin or inhaled.
It also appears that people who use moisturisers or children who have used antimicrobial soap containing triclosan who go swimming could also be a potential source of chloroform and other dioxins. As Peter Vikesland, one of the scientists at Virginia Polytechnic pointed out, "If someone who has a moisturiser containing triclosan jumps into the swimming pool….they’re a potential source for chloroform and chlorinated dioxin formation". 

Triclosan finding its way into rivers
However it is not just in domestic use that triclosan is potentially harmful. Scientists from the University of Minnesota** recently demonstrated that triclosan in river water can be converted by sunlight into dioxins.

This means that domestic products containing triclosan that are flushed down domestic drains into rivers could be converted into potentially harmful dioxins. Because this water eventually finds its way into wastewater treatment plants scientists are calling for more research to see whether these plants are releasing dioxins.
Dioxins are persistent and bioaccumulative chemicals, meaning they do not degrade over time, and can be accumulated in body tissues. Therefore even low-level inputs in to the environment can contribute to increasing concentrations further up the food chain. 

REACH doesn’t go far enough in treating mixtures
This recent research reveals the unintended result of mixing triclosan with chlorinated water and clearly demonstrates why WWF would like all available data on everyday chemicals to be provided through REACH.
Mixtures of a different kind are the focus of another piece of interesting research from the United States which highlights the kinds of challenges presently facing toxicologists and some shortcomings of the proposed EU chemicals legislation, REACH.

Research from the Harvard School of Public Health demonstrated that when two chemicals – PCBs and phthalates - interact they affect the human sperm’s ability to fertilise eggs properly. As the HSPH researchers say, "an understanding of how chemical classes interact is essential to determining risk because humans are concurrently exposed to numerous classes of chemicals".
This research has ramifications for the scope of REACH and chemical control in the European Union. While chemical companies had complained that REACH was too broad a proposal, it now appears that in some respects it does not go far enough. REACH as envisaged will evaluate the potential harm of individual chemicals but it does not stipulate that mixtures of chemicals should be tested. 

This new research demonstrates that while individual chemicals could be tolerated in small amounts, when they interact with others they might have more serious consequences. By omitting the possibility of evaluating chemical mixtures, the legislation leaves the door open for considerable sources of chemical risk for wildlife and humans.

* Formation of chloroform and chlorinated organics by free-chlorine mediated oxidation of triclosan. Krista L.Rule, Virginia R.Ebbett and Peter Vikesland, Envir.Sci.Technology; 2005

** Kristopher McNeill and William Arnold, Envir.Toxicol.Chem. 2005, 24, 517-525

For more information: 
Noemi Cano, Communications Manager
WWF DetoX Campaign
Tel: +32 2 743 8806
E-mail: ncano@wwfepo.org
New evidence has shown that wahsing dishes could have other more unpleasant effects.