By Kelly A. Reynolds, MSPH, Ph.D.

The year 2008 marks the 60th anniversary of the World Health Organization (WHO). Headquartered in Geneva Switzerland since 1966, the WHO is the premiere public health authority for the United Nations system. Since the organization’s beginning, it has contributed to major public health achievements including the introduction of poliovirus vaccines, the eradication of smallpox and development of strategies for controlling tuberculosis.

Other modern milestones include: establishment of The Global Outbreak Alert and Response Network (GOARN) (2000) for identifying and controlling the international spread of outbreaks; declaration of the Millennium Development Goals (MDG) (ca. 2000) challenging countries to achieve specific health-related targets by 2015; numerous initiatives to detect, control and treat HIV/AIDS, measles and SARS; promulgation of new International Health Regulations (2007) with 194 countries legally bound to prevent and respond to acute public health risks that may cross international borders; and a commitment to protect health from climate change (2008).[1]

More recently (December 2008) the WHO released updated guidelines for drinking water quality, identifying current threats, future considerations and other recommendations related to drinking water and human health.

A world in need
Drinking water and sanitation are two key components for reducing global mortality rates. Estimates of more than 2.5 billion people without improved drinking water and sanitation are staggering. The year 2008 was declared the International Year of Sanitation but global improvements lag far behind our public health goals. Diarrheal disease remains one of the top three causes of death in the world, with over 1.8 million deaths per year, primarily in children under the age of five.

There is some good news to report, however. From 1990 to 2006, approximately 1.5 and 1.1 billion people gained access to improved drinking water sources and sanitation, respectively. This is an increase from 77 percent of the population with access to improved water sources to 87 percent.

At this rate, the world’s overall Millennium Development Goals for 2015 are within reach. But some regions, such as sub-Saharan Africa and Oceania, are far below development goals, leaving large segments of the population vulnerable to disease.[2]

As countries progress toward a commitment to improved drinking water sources, many are following the WHO Guidelines for Drinking Water Quality. Aimed at health regulators, policymakers and other stakeholders, these published Guidelines provide tools for the development of national quality standards for safe drinking water.

The UN General Assembly declared the period from 2005 to 2015 as the International Decade for Action, ‘Water for Life.’ The Guidelines provide an important resource for countries to initiate practical improvements, which often yield a net economic benefit to the region.

Rolling revisions
In 1958, the WHO published the first edition of the International Standards for Drinking Water with successive editions published in 1963 (second edition) and 1971 (third edition). The next version of the document was published in 1984 under the new name of Guidelines for Drinking-water Quality, First Edition. This name better reflected the intention of the WHO to promote and advise, rather than regulate, international agencies for water quality.

The first edition was released in three volumes:

  • Volume 1, Recommendations—provides essential information on guideline values for various drinking water contaminants and the criterion used to evaluate the various microbiological, chemical and radiological contaminants considered.
  • Volume 2, Health Criteria and Other Supporting Information—focuses on health criteria for specific contaminants, listing guideline values and going into greater depth on the health risks of the contaminants listed in Volume 1.
  • Volume 3, Surveillance and Control of Community Water Supplies—deals primarily with small communities such as those in rural areas of developing countries and how to control contaminants and minimize potential risks.

The second Guidelines edition, released in 1993, included updated volumes listed above with the addition of documents on select chemical substances and microbes in water. As new information arises, the guidelines continually evolve through a process of rolling revision.

Addenda are routinely published and made available as supplemental information to the current guidelines edition, keeping up to date with the ever-changing database. Therefore, the third edition was released circa 2004, and differed from previous editions with a trend toward promotion of a preventive management and more holistic approach toward attaining quality water, utilizing tools of risk assessment and risk management.

Preparation of the third edition spanned a time frame of more than a decade and involved the participation of over 490 experts from 90 countries (developing and developed). This edition focused on source water protection and the scaling back of current end-use monitoring schemes to implement online monitoring for key contamination indicators (i.e., turbidity). Shortly thereafter (2006) the first addendum and an online Spanish translation of the document became available.

Significant updates
Most recently (December 2008), the WHO released an online version of the Guidelines for Drinking-water Quality, Second Addendum to the Third Edition, Volume 1, Recommendations.[3] Updates include much needed guidance on point of use (household) water management, alternative water supplies (rainwater harvesting, vended water and temporary water supplies) and pesticides used in drinking water sources, primarily for vector control. In addition, fact sheets on priority microbes and chemicals are available for select risks.

Furthermore, texts on the Health aspects of plumbing; Legionella and the prevention of legionellosis; Protecting groundwater for health-managing the quality of drinking-water sources; and Tolerable health based targets have been added. The next addendum is also expected to provide information on “Guidelines for the microbiological performance evaluation of point-of-use (POU) drinking water technologies.”

These detailed descriptions will likely provide fodder for On Tap in the coming year as we continue to provide summaries on current topics related to chemicals and microbes in drinking water.

The role of POU treatment
Due to the massive expense associated with centralized water treatment, approaches for de-centralized and household water treatment technologies are practical and desired in both the developed and developing world. There are many different types of household water treatment technologies but maintenance of a quality water supply is often affected by a lack of sanitation and hygiene.

Furthermore, regardless of the achievement of desired quality water, emergencies, engineering delays and periodic treatment failures occur. POU technology can provide effective controls; however, choosing the right POU treatment technology is largely dependent on the target contaminant and regional resources for treatment.

Globally, nitrates, arsenic and fluoride are the chemical contaminants of greatest concern and can be challenging to remove. Sometimes, chemical contaminants are detectable by the consumer because of an unacceptable taste, odor or appearance whereas the presence of harmful or even deadly microbial agents can easily go unnoticed.

The WHO Guidelines for Drinking-water Quality provide additional clarity on how better water can be achieved with both centralized and household treatment interventions.

References

  1. WHO 2008, WHO in 60 years: a chronology of public health milestones. World Health Organization, Geneva, Switzerland. www.who.int/features/history/who_60th_anniversary_chronology.pdf.
  2. UN-Water, 2008. Global annual assessment of sanitation and drinking water. 2008 Pilot Report. World Health Organization, Geneva, Switzerland.
  3. Guidelines for Drinking-water Quality, Second Addendum to the Third Edition, Volum 1, Recommendations (2008). World Health Organization, Geneva, Switzerland. http://www.who.int/water_sanitation_health/dwq/secondaddendum20081119.pdf.

About the author
Dr. Kelly A. Reynolds is an associate professor at the University of Arizona College of Public Health. She holds a Master of Science degree in public health (MSPH) from the University of South Florida and a doctorate in microbiology from the University of Arizona. Reynolds has been a member of the WC&P Technical Review Committee since 1997. She can be reached via email at reynolds@u.arizona.edu.

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