Shaky Science Can Cause Scare Over Chlorination

03/09/2002 The Dallas Morning News

By RALPH MORRIS

Since Hippocrates composed the ancient physician's oath that bears his name, the dictum "first, do no harm" has functioned as a cornerstone of medical ethics. While the Hippocratic oath clearly forbids direct action by a physician that might injure a patient, it also prohibits the irresponsible dissemination of misleading information that might cause people to act against their best health care interests.

A recent report by the Environmental Working Group alleges a link between miscarriages and "disinfection byproducts" in drinking water. While those assertions generate considerable public concern, definitive scientific evidence to support such accusations has been in much shorter supply. If such information isn't reported in the proper context, it may lead to unwise choices.

For more than a century, American water utilities have added chlorine to drinking water in order to destroy disease-causing bacteria and viruses. As a result of that disinfection process, waterborne diseases like cholera and typhoid that were the scourge of previous generations essentially have been eliminated in the United States.

Since the early 1970s, scientists have known that chlorine and other disinfectants can react with certain organic materials in water to produce "disinfection byproducts," including a group of chemicals known as "trihalomethanes." Some research has suggested a possible link between adverse reproductive effects and exposure to such byproducts. Yet the link is far from conclusive.

Even though the science is uncertain, the Environmental Protection Agency has taken precautionary measures designed to protect the public. It brought together a diverse group of experts that included environmental groups, water utility officials, public health agencies and others to reach an agreement that lowers exposure to disinfection byproducts while continuing to protect consumers from waterborne bacteria, viruses and other disease-causing organisms.

And what does the EPA have to say about the Environmental Working Group report? A statement from the agency asserted, "The EPA agrees with the EWG on the importance of continued research on the potential adverse reproductive and developmental effects from exposure to [disinfection byproducts]. However, the studies cited in the report don't support their argument that there is a link between current levels of exposure to [disinfection byproducts] and an increased risk of adverse reproductive and developmental health effects."

In other words, the EPA rejects the Environmental Working Group's assertions that the childbearing population of the United States is endangered by the tap water it drinks.

Moreover, one always must bear in mind the indispensable contribution made by water disinfection to the higher living standards and life spans that are part of our modern world. Life magazine cited the filtration of drinking water and use of chlorine disinfection as "probably the most significant public health advance in the millennium." Yet in poor nations, the World Health Organization estimates that 3.4 million people, mostly children, die each year from water-related diseases and that an additional 2.4 billion lack ready access to basic water sanitation. For that reason, the WHO has declared "the risk to health from disinfection byproducts is extremely small in comparison with inadequate disinfection."

The most troubling aspect of the Environmental Working Group's report stems from the potential that its scientifically unfounded allegations might induce some expectant mothers to adopt habits that could endanger their pregnancies. Drinking water is essential for health, especially during pregnancy. Yet not all women can afford to purchase large amounts of commercially bottled water. Thus, the report could sow the seeds of a health scare that might deter women from drinking the recommended eight glasses of water per day. That is precisely the sort of indirect harm of which Hippocrates would disapprove.

Dr. Ralph Morris is with the Galveston County Health District.

Reprinted with permission of The Dallas Morning News. ©2002, All rights reserved.