Sadly, some 1.2 billion people – one-sixth of the world’s population – still rely on unsafe water from rivers, lakes and open wells to meet their daily household needs. And every year, infectious diarrhea spread by contaminated water kills 2.5 million people, mostly children under five years old.

While the long-term goal should be safe water piped to every home, it will take many years to build the necessary municipal water systems. For those without access to safe water supplies, simple techniques – including chlorine disinfection with tablets or dilute bleach, boiling and ceramic filtration – for treating water at home and storing it in containers can save lives today. The World Health Organization has stated: “Household approaches, including treatment with chlorine disinfectants, have been shown to be extremely cost effective, rapidly deployable, and can lead to significant health gains.”

The Chlorine Chemistry Foundation, sponsored by the global chlorine industry, is helping to address the global water challenge, working with partners to build permanent water systems for small communities in developing countries. For more information on this important initiative, visit www.chlorinefoundation.org.

Chlorine destroys germs and has helped to virtually eliminate waterborne illnesses such as cholera and typhoid that once killed thousands of Americans each year. Indeed, as the 20th century neared its conclusion, Life magazine declared: “The filtration of drinking water plus the use of chlorine is probably the most significant public health advancement of the millennium.”

Efforts to improve drinking water date to the time when ancient civilizations established themselves around water sources. As early as 4,000 B.C., Sanskrit and Greek writings recommended filtering water through charcoal, exposing it to sunlight, boiling and straining to reduce visible cloudiness. Other ancient civilizations as diverse as Chinese, Arabian, Egyptian and Indian tried other coagulants, including alum, almonds, powdered ginger, cornmeal, crushed oyster shells and even toasted biscuits.

These early attempts were based on the notion that clear water not only tasted and smelled better, but was not apt to make a person sick. What went unrecognized until the 19th century was that the cause of most waterborne illnesses was not visible and could not necessarily be filtered out.

Dr. Snow and Removal of a Pump Handle
The year was 1854 and London was experiencing an epidemic of cholera -- an acute, diarrheal illness caused by infection of the intestine. While physician John Snow did not know what caused this sometimes fatal illness (and indeed the “germ theory” had not been formulated at this time), he was skeptical of the prevailing theories that cholera was caused by breathing foul air or was due to the alignment of the planets. After plotting cholera cases on a map and talking to residents, Dr. Snow pinpointed a public water pump as the probable source.

“On proceeding to the spot, I found that nearly all the deaths had taken place within a short distance of the pump,” Snow wrote in a letter to the editor of the Medical Times and Gazette. He persuaded the local council to remove the Broad Street pump handle, and the epidemic ended.

It was discovered later that the Broad Street well had been dug only three feet from an abandoned and covered cesspit that had begun to leak fecal bacteria into the water supply. Snow’s study was a major event in the history of public health. Many regard this English physician as the father of modern epidemiology – the study of factors affecting health and illness of populations and the cornerstone of public health research.

In 2003, the readers of Hospital Doctor magazine voted Snow the “greatest doctor” of all time, with Hippocrates, the father of medicine – coming in second. Not coincidentally, Hippocrates also addressed the importance of boiling and straining water to prevent disease. The cloth sack he endorsed for filtering water was called “Hippocrates’ sleeve.”

Killing Germs that Cause Disease
Standing on the sturdy shoulders of their predecessors, Louis Pasteur and other scientists in the 1800s verified “germ theory,” which explained how organisms too small to see with the naked eye could transmit disease through water and other media. During the very late 19th and early 20th centuries, scientists turned their attention to removing “germs” in public water supplies that caused epidemics of typhoid and dysentery, as well as cholera. They tried slow sand filtration first.

“While filtration was a fairly effective treatment method for reducing turbidity, it was disinfectants like chlorine that played the largest role in reducing the number of waterborne disease outbreaks in the early 1900s,” according to the U.S. Environmental Protection Agency.

In 1905, chlorine was added to London’s water supply and a typhoid epidemic ceased. Three years later, chlorination of Jersey City’s Boonton Reservoir and Chicago’s Bubbly Creek started a revolution that made chlorine the most widely used disinfectant in the United States. In that same momentous year, British scientist Harriet Chick figured out a relationship between germ kill efficiency and contact time with a disinfectant.

Based on Chick’s Law, cities across the United States adopted water chlorination rapidly, with more than 1,000 water systems using this life-saving technology by 1918. Then in the 1920s, Maryland Department of Health engineer Abel Wolman perfected the formula for the appropriate application of chlorine to water supplies.

In The Quest for Pure Water, which tells the story of water purification through Europe and the United States, M.N. Baker wrote in 1948: “Nothing in the field of water purification came into use as rapidly and widely, once it got started, as chlorination.” And what a difference chlorine made.

Chlorine Saves U.S. Lives, Helps Extend Lifespan
In the years before chlorine’s introduction, waterborne diseases claimed thousands of American lives every year. For example, there were more than 27,000 typhoid deaths during the Civil War. The widespread use of chlorine and improved sanitary engineering practices reduced the number of reported waterborne disease outbreaks and individual cases of waterborne illness dramatically.

In the decade 1900-1910, average U.S. life expectancy was 49 years. By 2005, a child born in the United States could expect to live 77.9 years, the U.S. Centers for Disease Control and Prevention (CDC) reported in September 2007. According to the CDC, the steep decline in infectious diseases made possible by vaccinations, chlorination of drinking water and other advances in public sanitation and hygiene directly contributed to this nearly 60 percent increase in life expectancy.

Chlorine: The Backbone of U.S. Drinking Water Infrastructure
Over the past 100 years, a national infrastructure has been developed using chlorine as a drinking water disinfectant. Chlorinated systems deliver water through nearly 900,000 miles of pipe to more than 200 million Americans. U.S. water systems provide some of the safest water in the world right to the home at a cost of up to 1,000 times less than bottled water – representing arguably the biggest bargain in a family budget.

Today, nearly nine out of 10 U.S. public water systems rely on chlorine in one form or another. Many systems use chlorine gas (elemental chlorine). Others use liquid chlorine bleach (sodium hypochlorite) or calcium hypochlorite (often also used in swimming pools). Each form produces “free chlorine” to destroy disease-causing microorganisms. Chlorine offers numerous other benefits, as well. For example, chlorine removes many unpleasant tastes and odors and certain metal contaminants, such as iron and manganese. Chlorine also provides a residual level of disinfectant to help keep water safe from the treatment plant to consumers’ taps.

All of the vast water-treatment infrastructure and the public health benefits it delivers track back to 1908, when Jersey City and the Union Stockyards of Chicago made very wise decisions to add chlorine to their water supplies. So, lift your glass of America’s finest and toast the health of all Americans on this 100th anniversary of water chlorination.

References
Chlorine’s Proven Benefits as a Drinking Water Disinfectant, Chlorine Institute, Arlington, Va.

Chlorine’s Proven Value in Assuring Safe Drinking Water, Chlorine Institute, Arlington, Va.

“Disinfection Contact Time and Kinetics” by Eric Karch and David Loftis, Water Treatment Primer, Civil Engineering Department, Virginia Tech

Drinking Water Chlorination: A Review of Disinfection Practices and Issues (2003), a publication of the Chlorine Chemistry Division of the American Chemistry Council and the Canadian Chlorine Coordinating Committee.

Drop of Life: Delivering Safe Water to the World, World Chlorine Council

“History of water disinfection,” Lenntech Water treatment & air purification Holding B.V., Delft, The Netherlands

“John Snow – a historical giant in epidemiology,” University of California – Los Angeles School of Public Health, Department of Epidemiology, Los Angeles, Calif.

“Safe Water Should Always Be on Tap” by Kathy Jesperson, National Drinking Water Clearinghouse, West Virginia University

“The History of Drinking Water Treatment (2000)”, U.S. Environmental Protection Agency, Washington, D.C.

The Importance of Safe Drinking Water, Chlorine Institute, Arlington, Va.

The Quest for Pure Water (1948), M.N. Baker, American Water Works Association, Denver, Colo.

“U.S. Life Expectancy Hits New High of Nearly 78 Years” (Sept. 12, 2007), U.S. Centers for Disease Control and Prevention, Atlanta, Ga.

Water Quality & Treatment: A Handbook of Community Water Supplies, 5^th Edition, American Water Works Association, 1999.

World Health Organization