Drinking Water

The availability of safe water is arguably the most critical environmental issue faced by public health practitioners. Water is essential not only for growing food crops, but access to safe drinking water is a major concern to all human populations and a significant challenge to public health and government planning officials, particularly in the developing world. Despite the vast abundance of water on the planet, only 1% of this is available for use by humans, and only a fraction of that is readily potable, mostly in the form of groundwater reserves.

The link between clean water and health has been recognized for several thousand years, long before the germ theory of disease, which only became widely accepted by the medical community less than a century and a half ago. In 1854, Dr. John Snow conducted the first known field epidemiology study investigating the source of a London cholera outbreak, which turned out to be due to a public water pump supplied by a contaminated source. With respect to drinking water, the germ theory subsequently led to the development of improved sanitation methods, such as chlorination of drinking supplies, which greatly improved public health in the developed world.

Unfortunately, many of those advances are still not readily available in the developing world. Lack of resources to be able to develop the necessary infrastructure is a significant challenge. According to the 2010 WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation (JMP), 2.6 billion people worldwide, most of those in Asia, do not use improved sanitation, and 884 million people lack access to improved sources of drinking water, with Sub-Saharan Africa facing the greatest challenges (JMP, 2010).

My own experience traveling in India reflects the information in the JMP report. In 2009, I spent some time conducting a small scale spay-neuter project in a small village in rural Himachal Pradesh state, in the Himalayan foothills. The JMP report indicates that while improved drinking sources are available to 76-90% of rural areas, improved sanitation facilities are still below 50%. While the village where I stayed did have running water for most homes and a municipal water pump and public toilets for those who did not have indoor plumbing, there was no piped sewage system.

For most homes, toilet facilities were shared among households and typically in separate buildings from the living quarters. My observation was that all toilet facilities appeared to dump directly into small streams, which would be expected to affect communities living downstream. Additionally, water supplies of homes on the mountainside were generally from cisterns which were periodically replenished by the controlling state agency, but which had to be rationed during a recent drought. The friends with whom I stayed had a ceramic micropore filtration system to further ensure the safety of their personal drinking water supply, but they are relatively well off Westerners and my sense was that this was well outside the ability of the bulk of the local populace to afford.

The importance of safe drinking water supply was highlighted relatively recently by the 2010 outbreak of cholera in Haiti, the first in that country in over a century and one of the worst in recent history. Starting in rural Artibonite department, to the northwest of Port-au-Prince, the disease was spread primarily by fecal-contaminated drinking water and lack of clean water for hygiene and came just months after the country’s already strained infrastructure was devastated by the January 2010 earthquake. Over 470,000 cases were reported in the outbreak, with 6,631 known attributable deaths (CDC website).

Anecdotally, a great aunt of mine, who has been involved in an effort through her church to dig community wells in Haiti since before the earthquake and who has made several visits to the country, reports communities having to obtain drinking water from shallow, muddy pits. The outbreak prompted an increased international effort to provide safe wells for drinking water and latrines for improved waste management, but lack of infrastructure and limited access to remote areas still pose challenges.

Another concern at the global level is the presence of persistant organic pollutants in drinking water sources. A recent review of reported contaminant levels in surface waters in China, from which drinking supplies are primarily derived, showed high levels of numerous organic pollutants - including organochlorine pesticides such as DDT, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p­- dioxins (PCDDs), and others (Bao, L.J., et al. 2012). Another recent study conducted in Haryana state in northern India found excessive levels of organochlorine pesticides in 37% of drinking water samples collected (Kaushik, C.P., Sharma, H.R., and Kaushik, A., 2012).

This summary is hardly exhaustive and doesn’t begin to address all the possible considerations of drinking water quality and access. It should, however, provide a glimpse into the complexity of the challenges involved in working toward a goal of ensuring the availability of safe and accessible drinking water for the entire human population.

References

Moeller, D.W. Environmental Health, Fourth Edition. Harvard University Press. 2011.

Joint Monitoring Programme for Water Supply and Sanitation. Progress on Sanitation and Drinking Water: 2010 Update. World Health Organization and UNICEF. 2010.

CDC website on Haiti cholera outbreak. http://www.cdc.gov/haiticholera/haiti_cholera.htm

Bao, L.J., et al. “China’s water pollution by persistent organic pollutants”. Environmental Pollution. 2012 Apr; 163: 100-108. doi: 10.1016/j.envpol.2011.12.022

Kaushik, C.P., Sharma, H.R., and Kaushik, A. “Organochlorine pesticide residues in drinking water in rural areas of Haryana, India”. Environmental Monitoring and Assessment. 2012 Jan;184(1):103-12. doi: 10.1007/s10661-011-1950-9