Dear Editor:

The recent article, Chlorine Removal Showerhead Filters [April 2007], does a disservice to your readers. Instead of educating consumers about home filtration products, the article misleadingly criticizes the quality and safety of chlorinated water supplied by public drinking water systems.

While acknowledging chlorine’s essential role in preventing waterborne disease, the article draws together misleading and alarmist statements about this life saving element. What his article does not make clear is that numerous government authorities have reviewed the data and concluded that the amount of chlorine typically used to disinfect tap does not itself pose any foreseeable risk to human health. For example, the U.S. EPA’s maximum allowable level for chlorine in drinking water is 4 mg/liter, a level at which EPA believes “no known or anticipated adverse effects on the health of persons occur and which allows an adequate margin of safety” [emphasis added]. Even this level is significantly higher than what typically comes out at the tap.

The article raises the issue of exposure to disinfection byproducts (DBPs). It has been known since the 1970’s that chlorine and other disinfectants can react with naturally occurring organic material to form chloroform and other DBPs. It is correct that some exposure to chloroform is likely to occur during showering. It should be noted though, that chloroform levels in drinking water are well studied and regulated both in Canada and the U.S. In fact, U.S. EPA’s health-based standard is intended to be protective of human health, even assuming that a person more exposure through showering and other routes as he or she does from consuming tap water.

The author’s reference in the article to carbon tetrachloride and trichloroethylene (TCE) is misleading; while both chemicals have been found as a contaminant in some groundwater supplies, neither are formed during the water treatment process. It is unfair to characterize the use of chlorine in water disinfection as the source.

Chlorine treatment of household water supplies has been called one of the greatest public health advances in history. Organizations that promote the use of household treatment systems should focus on the merits of their own products and services, and not spread misleading allegations about the quality of public water supplies. But Mr. Wong does not have to follow my advice. He only needs to read his organization’s own code of ethics (

Yours sincerely,

Allan Jones Ph.D.
Executive Director
Canadian Chlorine Chemistry Council

Dear Editor:

I am writing to protest the tenor and the details of the article by Kevin Wong, Chlorine Removal Showerhead Filters, which appeared in the April 2007 edition of your magazine.

I have two interests in this. I represent municipal water utilities who are required to provide water that meets the requirements of provincial and federal standards for delivered ‘drinking’ water quality—these requirements include a requirement to have a chlorine/chloramine residual to ensure the safety of the drinking water. I am also Chair of the NSF Joint Committee on Drinking Water Treatment Units which published NSF/ANSI Standard 177: Shower Filtration Systems—Aesthetic Effects and which addresses the performance of these devices.

In respect of both interests, we (and your readers) should be made aware and understand that both Canadian and US drinking water standards require chlorine residuals in water supplied by water utilities that are approximately 25 percent of the level declared by US EPA to be of NO public health concern. Accordingly, Standard 177 is an aesthetics standard, not a health standard.

It is unfortunate that the general public’s fears and concerns about many things, including chlorinated water services, can be raised by ‘scientific’ information that ignores the basic facts that chlorine residuals are there for a purpose and at levels determined by competent public health and environmental agencies that protect public health and are not expected to harm.

The CWQA, like the WQA, has a Code of Ethics which appears to have been contravened by the tenor and details of this article.

T. Duncan Ellison
Executive Director
Canadian Water and Wastewater Association




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