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Water and Health: Global Issues and Our Shared Responsibilities

Water and Health
Reported by
Chris Williams

Posted January 12, 2010


Ensuring that people have access to sufficient supplies of clean water has become one of the great challenges of the 21st century. Demand for water is growing rapidly and lack of access is implicated in malnutrition and widespread disease. At a November 13, 2009, NYAS symposium organized in collaboration with the Johns Hopkins Bloomberg School of Public Health, four experts provided a wide-ranging set of perspectives on the importance of water in our lives, from its role in global social, economic, and political trends, all the way down to the individual human cell. Topics discussed included the role of climate change in exacerbating cholera epidemics, threats to the U.S. water supply, high- and low-tech inventions for water treatment, and the implications of water shortages for economic development worldwide.

Nobel laureate Peter Agre surveys some examples of pressing problems in the United States and around the world arising from threats to water supplies.

Use the tabs above to find a meeting report and multimedia from this event.

Presented by

  • Johns Hopkins Bloomberg School of Public Health
  • Johns Hopkins School of Advanced International Studies

Photo credit: Shehzad Noorani

Aquaporin Water Channels: Nature's Plumbing System

Peter Agre (Johns Hopkins Bloomberg School of Public Health)
  • 00:01
    1. Introduction
  • 03:22
    2. Water selective channels and red cell membranes; Aquaporin-1
  • 09:55
    3. AQP1 and human renal function
  • 14:36
    4. The aquaporin family
  • 20:58
    5. Glycerol transporters; Malaria; Obesity; Arsenic toxicity
  • 27:21
    6. Aquaporin functions in plants
  • 27:54
    7. Conclusio

Staying Above the Surface: Global Water Futures

Erik R. Peterson (Center for Strategic and International Studies)
  • 00:01
    1. Introduction
  • 05:31
    2. Unsustainable water use patterns
  • 09:57
    3. Future water shortages
  • 15:09
    4. Water dislocations and supply
  • 18:16
    5. Future water policy
  • 25:04
    6. The bottom lines; Conclusio

Water in the 21st Century: Public Health on the Front Lines

Kellogg J. Schwab (Johns Hopkins Bloomberg School of Public Health)
  • 00:01
    1. Introduction
  • 03:48
    2. A global water program
  • 10:19
    3. Bottled vs. tap water
  • 14:13
    4. Water and sanitation in the developing world; Overall basic water requirement
  • 16:34
    5. Water treatment technologies
  • 17:53
    6. Summary and what we can do; Conclusio

Panel Discussion

  • 00:01
    1. Introduction; Moderator's questions to the panel
  • 09:54
    2. Water reuse
  • 13:59
    3. Giardiasis
  • 17:01
    4. Infrastructure
  • 19:35
    5. PlayPumps
  • 22:08
    6. Conservation incentives
  • 25:21
    7. Integration with other development efforts
  • 27:23
    8. Aquaporins, inflammation, and aging
  • 30:20
    9. Resolving international water disputes
  • 34:05
    10. Water purity, population density, and rural culture
  • 42:05
    11. Agricultural use
  • 44:18
    12. Scarcity and population growth
  • 50:05
    13. Water policy prospects
  • 54:20
    14. Cholera reduction in unpurified water
  • 56:47
    15. The Safe Drinking Water Act; Water and energy
  • 62:07
    16. Privatization
  • 64:46
    17. Friends of the Earth; Israeli policy
  • 69:35
    18. The question of quotas
  • 72:12
    19. Judging risk; Microcontaminants
  • 77:25
    20. Cholera and climate change
  • 79:15
    21. City of New York policy
  • 80:41
    22. Closing remarks and conclusio

Climate, Oceans, Global Warming, and Infectious Disease:
the Cholera Paradigm

Rita R. Colwell (University of Maryland College Park)
  • 00:01
    1. Introduction
  • 03:27
    2. Water quality and human health; The case of cholera
  • 07:20
    3. Model for transmission; The geographic picture
  • 13:40
    4. Environmental relationships; Temporal patterns of transmission risk
  • 20:40
    5. Prevention through water filtration; Filtering arsenic
  • 27:09
    6. The molecular genetics of cholera
  • 29:49
    7. Conclusio

Web Sites

100 Ways to Conserve Water
Tips for simple things you can do at home to avoid wasting water.

American Society of Civil Engineers Report Card
In 2009, the ASCE gave the U.S. water infrastructure a grade of D−. Learn why here, and find out more about other infrastructure needs.
Basic information about aquaporin function and their importance in human disease, and updates in aquaporin research.

Global Strategy Institute
The Global Strategy Institute is exploring the implications of water scarcity for global security in its Global Water Futures initiative. See Erik Peterson and Rachel Posner's report, Global Water Futures: A Roadmap for Future U.S. Policy.

Johns Hopkins Center for Water and Health
Learn more about the wide range of water research being conducted at Hopkins.

Johns Hopkins School of Advanced International Studies
The 2008 issue of the school's SAISPHERE magazine, titled Water: the New Reality, includes an essay from Erik Peterson.

Potters for Peace
Since 1998 Potters for Peace has traveled the world teaching the fabrication of a low-cost ceramic water filter, helping to bring clean, potable water to those who need it most.

Running Dry
A grassroots campaign working to ensure access to safe, affordable, and sustainable drinking water and adequate sanitation around the world.

United States Agency for International Development (USAID)
Information about USAID's water projects on topics including watershed protection, coastal management, and freshwater systems management.

United States Environmental Protection Agency—Office of Water
The USEPA works work to: ensure drinking water is safe; protect and restore oceans, watersheds, and other aquatic ecosystems; and provide healthy habitats for fish and wildlife, plants, and people.

UN Water
Information from the United Nations' water development efforts. See their flagship publications and statistics for more information.

Water in the U.S. Congress
The U.S. Congress has begun taking steps toward supporting water security around the world. Passed in 2005, the Paul Simon Water for the Poor Act set the goal of providing 100 million people around the world with sustainable access to clean water and sanitation by 2015. Currently under development, Senator Richard Durbin's Water for the World Act would set more robust goals.

World Health Organization—Water, Sanitation, and Health
WHO works on aspects of water, sanitation, and hygiene where the health burden is high, where interventions could make a major difference, and where the present state of knowledge is poor.


Peter Courtland Agre, MD

Bloomberg School of Public Health
e-mail | web site | publications

A native Minnesotan, Peter Agre studied chemistry at Augsburg College and medicine at Johns Hopkins. He completed his residency at Case Western Reserve University in Cleveland and an oncology fellowship at the University of North Carolina at Chapel Hill. Agre joined the Johns Hopkins School of Medicine faculty in 1984 and rose to the rank of professor of biological chemistry and professor of medicine. In 2005, he moved to the Duke University School of Medicine, where he served as vice chancellor for science and technology and James B. Duke Professor of Cell Biology. Agre returned to Johns Hopkins in January 2008, where he is university professor and director of the Malaria Research Institute at the Bloomberg School of Public Health.

In 2003, Agre shared the Nobel Prize in Chemistry for discovering aquaporins, a family of water channel proteins that is found throughout nature, is responsible for numerous physiological processes in humans, and is implicated in multiple clinical disorders. He has received other honors including 15 honorary doctorates, Commandership in the Royal Norwegian Order of Merit from King Harald V, and the Distinguished Eagle Scout Award from the Boy Scouts of America. Agre is a member of the National Academy of Sciences and the Institute of Medicine, for which he chaired and serves on the Committee on Human Rights. In February 2009, he became president of the American Association for the Advancement of Sciences.

Rita R. Colwell, PhD

Johns Hopkins University Bloomberg School of Public Health;
University of Maryland College Park; CosmosID, Inc.
e-mail | web site | publications

Rita Colwell is Distinguished University Professor both at the University of Maryland at College Park and at Johns Hopkins University Bloomberg School of Public Health. She is also senior advisor and chairman emeritus of Canon U.S. Life Sciences, Inc., and president and CEO of CosmosID, Inc. Her work focuses on global infectious diseases, water, and health, and she is currently developing an international network to address emerging infectious diseases and water issues, including safe drinking water for both the developed and developing world.

From 1998 to 2004 Colwell served as the 11th director of the National Science Foundation. She has held many advisory positions in the U.S. government, nonprofit science policy organizations, and private foundations, as well as in the international scientific research community. She was president of the University of Maryland Biotechnology Institute and professor of microbiology and Biotechnology at the University Maryland. She was also a member of the National Science Board from 1984 to 1990.

Colwell has previously served as chairman of the Board of Governors of the American Academy of Microbiology and also as president of the American Association for the Advancement of Science, the Washington Academy of Sciences, the American Society for Microbiology, the Sigma Xi National Science Honorary Society, and the International Union of Microbiological Societies. She is a member of the National Academy of Sciences, the Royal Swedish Academy of Sciences, Stockholm, the Royal Society of Canada, the American Academy of Arts and Sciences, and the American Philosophical Society. She is president of the American Institute of Biological Sciences (AIBS).

Colwell has also been awarded 54 honorary degrees from institutions of higher education, including her Alma Mater, Purdue University and is the recipient of the Order of the Rising Sun, Gold and Silver Star, bestowed by the Emperor of Japan, and the 2006 National Medal of Science awarded by the President of the United States. Colwell is an honorary member of the microbiological societies of the UK, Australia, France, Israel, Bangladesh, and the U.S. and has held several honorary professorships, including the University of Queensland, Australia. A geological site in Antarctica, Colwell Massif, has been named in recognition of her work in the polar regions.

Erik R. Peterson, MBA, MA

Center for Strategic and International Studies
e-mail | web site

Erik Peterson is senior vice president at the Center for Strategic and International Studies (CSIS), a Washington, DC-based bipartisan and nonprofit think tank on foreign policy and national security issues. He also serves as director of the Global Strategy Institute—a "think tank within a think tank" he established at CSIS in 2003 to assess long-range trends. Prior to assuming his role as director of the Global Strategy Institute, Erik was director of Studies at CSIS. In that capacity, he oversaw and coordinated programs, projects, and publications across the organization. Before joining CSIS, Peterson was director of research at Kissinger Associates, the international consulting firm chaired by former Secretary of State Henry A. Kissinger.

Peterson serves on several advisory boards, including the X Prize Foundation, the Center for Global Business Studies at Pennsylvania State University, and the Center for the Study of the Presidency. He has also served as a fellow of the World Economic Forum and a member of the Forum's Global Risk Network. In October 2008, he was appointed visiting scholar at the John Hopkins University School of Advanced International Studies (SAIS). He lectures regularly for a wide array of U.S. government institutions, including the Army Medical Strategic Leadership Program, Army War College, Coast Guard, Department of Agriculture, Department of Defense, Department of Energy, Department of State, Interagency Institute for Federal Health Care Executives, Internal Revenue Service, Joint Chiefs of Staff, National Defense University, Proteus, Reserve Forces Policy Board, and USAID. The author of several publications, he is now completing a book on global strategic trends and their effects on governance structures in societies across the world.

Peterson received his MBA from the Wharton School at the University of Pennsylvania, his MA from the Johns Hopkins University SAIS, and his BA from Colby College. He holds the Certificate of Eastern European Studies from the University of Fribourg (Switzerland) and the Certificate in International Legal Studies from the Hague Academy of International Law (The Netherlands).

Kellogg Schwab, PhD, MS

Johns Hopkins University Bloomberg School of Public Health
e-mail | web site | publications

Kellogg Schwab is an associate professor in the Department of Environmental Health Sciences at the Johns Hopkins University Bloomberg School of Public Health and Director of the JHU Center for Water and Health. In January 2009, in collaboration with JHU colleagues, he initiated the JHU Global Water Program. This program integrates Hopkins researchers from public health, engineering, behavior, policy, and economic disciplines to address the critical triangle of water, food, and energy. The goal of this program is to achieve sustainable, scalable solutions for disparate water needs both internationally and domestically.

Schwab's research focuses on environmental microbiology and engineering with an emphasis on the fate and transport of pathogenic microorganisms in water, food, and the environment. Applying advanced molecular diagnostic tools, he has developed and participated in multiple research projects designed to evaluate the public health impacts of improving water access and potable water quality, the effectiveness of point-of-use water treatment, and the health effects of inadequate management of human and animal waste. He has also been involved in assessing novel water treatment processes and developing approaches for microbial risk assessment. Recent international work has focused on evidence-based assessments of point of use and community level water treatment systems designed to provide potable water to individuals in low income countries. Schwab earned his masters and doctoral degrees at the University of North Carolina at Chapel Hill School of Public Health, and then completed a postdoctoral fellowship at Baylor College of Medicine.

Christopher Williams

Christopher Williams is Executive Web Editor at the New York Academy of Sciences.


Presented by

  • Johns Hopkins Bloomberg School of Public Health
  • New York Academy of Sciences
  • Johns Hopkins School of Advanced International Studies

In most places in the developed world, we take high-quality potable water for granted. It comes out of our taps and flushes away our waste 24 hours a day, 7 days a week, 365 days a year, raising little concern that it will cause us harm. But in many places, ensuring that people have access to sufficient supplies of clean water has become one of the great challenges of the 21st century.

The UN Commission on Sustainable Development projects that demand for water will double by the middle of this century, and increase at a rate of 50% with each subsequent generation. Africa, the Middle East, and Asia are likely to be particularly vulnerable, and it is estimated that the portion of humanity that will not have access to sufficient or clean water supplies will increase from 1/3 to 2/3. Even in the United States, regions spanning a wide band in the South are facing increased threat of water shortages.

Today approximately one-half of all hospitalizations around the world are due to waterborne diseases. Nearly 2.5 billion people have poor sanitation, and lack of access to sufficient water supplies is implicated in approximately half of all malnutrition. Because many people have no choice but to use the same water supplies for both drinking and sanitary purposes, waterborne diseases such as cholera, typhus, E. coli infection, and dysentery are a constant threat in many places, with children paying a particularly high toll. Meanwhile, population growth and climate change threaten to make all of these factors much worse.

"In effect, we are on countdown," remarked Erik Peterson, director of the Center for Strategic & International Studies, at a November 13, 2009, NYAS symposium organized in collaboration with the Johns Hopkins Bloomberg School of Public Health. The meeting featured four experts who provided a wide-ranging set of perspectives on the importance of water in our lives, from its role in global social, economic, and political trends, all the way down to the individual human cell.

Water, global policy, and international security

One of the most disturbing things Peterson finds about water is the global community's inability to understand the magnitude of the problem it poses, and to develop effective public policy for managing the resource. At the same time that patterns of water usage have become unsustainable, he pointed out, there is no commonly accepted pricing and allocation structure, and only limited understanding of how sectors like energy and agriculture are dependent on water availability.

Water is thus not only a public health and environmental issue, but affects social relations, economic prosperity, and—with 260 basins around the world shared by more than two countries—an increasingly important strategic issue. "Clearly, we need to find a better way to build [into] the public policy sphere this critical resource that affects so many people at so many levels," Peterson argued.

Particularly in the developing world, water shortages have many implications for development. Peterson cited data from the United Nations and World Bank about Ethiopia that correlated reductions in gross domestic product with years of less rainfall. Lack of access to safe drinking water and sanitation services also has huge opportunity costs. UNICEF has suggested that lack of sanitary facilities at schools is an important reason for girls' high dropout rates in sub-Saharan Africa. A UN survey of 177 countries also determined that women lose approximately 40 billion working hours each year walking long distances to fetch water for their families.

The challenge of ensuring access to sufficient water is complicated by the fact that energy production is dependent on water availability. As population grows, energy demands are also growing, which means the energy sector will need more water to meet everyone's needs. Peterson pointed out that policymakers considering investments in nuclear power generation need to understand that it requires significantly more water than other generating methods. "As we see countries trying to find energy solutions for increasing populations," he said, "they'll need to be thinking long and hard about how to find sufficient water to deal with that increased energy production."

Some important interactions between water, energy, and agriculture (slide courtesy of Erik Peterson).

Similarly, with 70% of worldwide water use going to agriculture, the dynamic links between water, energy, and farming could lead to political instability. Citing the protests that occurred in the spring of 2008 when rising fuel costs caused food prices to spike, Peterson forecast, "As the global economy revives, the likelihood is that [with] additional increases in demand, especially in the areas of energy and food, we're likely to see the geopolitics of resources assume ever sharper definition."

Developments such as these suggest that there is an "ironclad case" for making water a core element of an integrated international policy strategy in the United States, Peterson said. There is a spectrum of goals and interests in relation to water, from human health, to humanitarian aid, to gender equality, to economic development, to environmental sustainability, to geopolitical stability, although currently there is only minimal integration among the various federal agencies for whom water is a concern.

In a CSIS report published in 2008 with coauthor Rachel Posner, Peterson recommends creating a new Bureau for International Water Policy that be tasked with "speaking for water" in collaboration with the U.S. State Department, the United States Agency for International Development (USAID), and other policy-making bodies. Developing an integrated, far-sighted water policy would recognize that addressing the issue is not just altruism, but is very important to national interests—particularly, he concluded, because "these pressures are growing by the day."

Cholera and climate change

Environmental microbiologist Rita Colwell has studied cholera for 40 years, and sees it as a case study for understanding a disease caused by an environmental bacterium, coupled with the effects of poor sanitation on human health. The cholera story is also one that she sees as emblematic of the ways in which climate change could exacerbate current challenges posed by infectious diseases.

Cholera is caused by ingestion of the bacterium Vibrio cholerae, which replicates in the small intestine of humans. Toxins produced by V. cholerae cause massive loss of fluid and death within hours if not treated. It is an ancient disease and the causative agent, Vibrio cholerae, is found in aquatic environments in many parts of the world. Cholera, in some years, causes approximately 250,000 deaths. In Zimbabwe, an ongoing cholera epidemic that public health officials have connected to corruption in the Mugabe government has had a fatality rate of 30%–40% in some parts of the country.

Although researchers once believed that the only mode of transmission of cholera was from person to person, Colwell and her colleagues have ascertained that Vibrio cholerae is associated with seasonal zooplankton and phytoplankton blooms. These creatures proliferate when seas warm, and can move up into rivers when sea levels rise. These factors combine to cause cholera outbreaks seasonally, typically in spring and fall, when humans ingest water containing the Vibrio-carrying organisms.

Two sets of graphs comparing epidemiologic data (black) with Colwell's team's predictive models (blue and red) in Kolkata, India and Matlab, Bangladesh.

Using satellite-based remote sensing to observe factors such as sea level fluctuations, the presence of chlorophyll, and water temperature, Colwell and her colleagues are developing models to predict cholera epidemics in Bangladesh, India, and Senegal months before they occur. What they have discovered reflects the important role of the aquatic world for human health. "The effect of poor sanitation is, of course, person-to-person transmission, but the source is really the environment," Colwell observed. "This tells us that we are very intertwined with the environment and that water is fundamental to our lives and health. If we do not have access to safe water, we have a devastatingly serious health problem."

Warming and rising seas threaten to make these problems worse, not only from the perspective of disease, but also with regard to the habitability of many low-lying areas of the world. Colwell remarked, "It grieves me to have to point out that with a predicted one-meter rise in sea level, we are going to see 17%–20% of Bangladesh permanently underwater, which means that we will have perhaps 100 million climate change refugees. Furthermore, if the glaciers in the Himalayas recede to the point of disappearance, we will have a water shortage of immense proportions occurring in this country, which already suffers as one of the poorest, economically, in the world."

Water issues in the United States

Although the areas most threatened by water shortages and contamination are in the developing world, Kellogg Schwab, director of the Johns Hopkins Center for Water and Health, reminded the audience that "if you look within the United States, we have extreme water needs within our own country.... It's not an 'us-them' issue, it's a 'we' issue."

Much of the country benefits from an abundance of rain, but areas including California, the Atlanta area, and the Southwest have faced dangerous droughts in recent years. Moreover, much of the nation's water infrastructure is aging and fragile, and will be very expensive to upgrade. And even if the arrival of chlorinated drinking water in the early 1900s effectively ended the era when Americans had to fear dying from cholera or typhoid, a host of emerging contaminants in the U.S. water supply—including pharmaceuticals, endocrine disrupting compounds, methyl tertiary butyl ether (MTBE), tetrachloroehtylene (TCE), and bisphenol A—are posing new kinds of health threats.

Schwab sees a paradox at the core of the water problem. "I attest to you that water is an inalienable right for every one of us," he asserted. At the same time, however, those who own water rights defend them vigorously, and "to produce high-quality, potable water takes money, resources, and energy." Ongoing debate is exploring the question of how to account for this fundamental economic issue, and whether passing the true costs of extraction and delivery along to users could help ensure accountability and financial sustainability.

Technologies for the developing world

Schwab pointed out that a variety of existing technologies—including clay pots, membrane filtration, and community water treatment plants—can improve sanitation in the developing world. The challenge is how to deliver these devices to communities in ways that effectively address their needs.

One new approach that engineers have begun to investigate is whether aquaporins could be used to filter contaminants from water. Peter Agre was awarded the 2003 Nobel Prize in Chemistry for discovering aquaporins, channels in the cell membrane that allow water to move inside the cell without resistance. At the Academy he provided an overview of the roles of various aquaporin subtypes in human health, and their vital roles in maintaining water equilibrium in the body. Aquaporin dysfunction in this class of proteins is implicated in a range of conditions, including pulmonary capillary defects, diabetes, congenital cataracts, malaria, and hyperthermia.

Schwab explained that researchers at Hopkins and elsewhere are exploring whether it might be possible to create a living membrane made of auquaporins that would exclude everything except H2O. This approach would be high-tech in the laboratory, but if developed well, could be low-tech, and therefore more practical, in the field.

Demonstration of a simple water filtration method in Bangladesh. Photo courtesy of Rita Colwell.

Referring to her team's discovery of the role of plankton in cholera, Rita Colwell also described a low-tech intervention they conducted to help defend villagers in Bangladesh against the disease. After testing its effectiveness in the laboratory, they conducted a three-year study educating the women to fold old sari cloth, the material used to make their dresses, over the openings of their pots when gathering water for their families. "We found that we could reduce cholera 50% by this simple filtration technique," she explained. Their effort had a persistent effect, and as word spread, control villages started filtering as well. The strategy helped to reduce the incidence of cholera even in local homes that did not filter due to the herd effect on disease transmission. Colwell is also working with Abdul Hassam, a colleague in Bangladesh, on another low-cost filtration technique to remove arsenic from well water.

Behavioral interventions can also have an effect in the West. Schwab encouraged the audience to be aware of their water consumption. In the United States, where a flush of the toilet is equal to the volume of water consumed by a person in many parts of the world in a day, personal decisions that can help conserve water are also important. In the question and answer period following the formal lectures, discussion considered the roles that taxation, financial incentives, and better education could play in reducing water use.

If there was an overarching message to the meeting, it was that solving the problem of delivering safe water will only occur with a focused, forward-thinking, and interdisciplinary effort. As Colwell observed, the problem "is a scientific, a social behavioral, an economic, an engineering, and a political problem, and you need all these dimensions. This means it's a tough problem, but it's a problem that has to be solved."

Open Questions

Technologies such as canal lining, drip irrigation, desalination, and drought-resistant seeds can reduce water consumption by agriculture. What policies could promote their more widespread adoption?

How can resources be better mobilized to promote the availability of cheap, high-impact technologies for purifying water in developing countries?

What balance of taxation, financial incentives, regulation, and education could effectively promote more sustainable water use practices?

How can greywater recycling, which reduces the energy needed to purify water by using non-potable water for non-drinking uses, be better integrated into residential and commercial buildings?

In 2009, the ASCE gave the U.S. water infrastructure a grade of D-, suggesting that major investments are needed. Will sufficient resources be allocated to make the necessary upgrades? If not, what will the results be?

To date, Erik Peterson's proposals for a new federal bureau focused on water have not received strong support in Congress. Will the federal government develop a more focused and better integrated international water policy?

Could models of water conservation such as those seen in Israel and Singapore be applied in other regions?