Water Quality and Human Health

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Water Quality and Human Health

The distribution of water-rich and water-poor regions is of course not the whole story – access to clean water isn’t just about the amount of water that falls as precipitation. It’s also about the infrastructure needed to obtain, treat, transport, and deliver potable water. And that’s just the water supply. Disposal and sanitation of dirty water are equally important and require a means of transporting waste away from the distributed sources, collecting it and treating it, and discharging it safely. Ideally, both supply and waste conveyance systems should also be monitored for performance and for their impacts on water quality.

In some areas, water is plentiful, but access to clean water is not (Figures 7-8). The converse is also true, mainly in developed nations where water projects, desalination, or dams provide a water supply to regions that receive little precipitation. There is also a clear distinction between access to clean water in rural and urban areas (Figure 7), wherein access in rural areas, even in developed nations, lags behind that in urban areas.

Bar graph shows urban and rural access to clean water supply. see text description
Figure 7: Access to clean water supply and sanitation in urban and rural areas. Note that rural areas lag behind urban ones in access to clean water and sanitary disposal, and developing nations lag behind developed ones.

Click the link to expand for a text description of Figure 7.8
Access to clean water supply and sanitation in urban areas.
Year Status Water Supply Improved Sanitation
1990 World 95% 79%
1990 Developing 92% 61%
2004 World 96% 80%
2004 Developing 91% 70%
Access to clean water supply and sanitation in rural areas.
Year Status Water Supply Improved Sanitation
1990 World 63% 26%
1990 Developing 61% 19%
2004 World 72% 39%
2004 Developing 70% 35%
Source: United Nations Environment Programme Vital Water Graphics

Learning Checkpoint

1. What is the primary trend shown in Figure 7 above, with respect to urban vs. rural areas?

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ANSWER: Urban areas have better access to both sanitation and potable water.

2. Is there a major difference in access to clean water supply and sanitation when comparing developed and developing nations?

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ANSWER: There is. In general, access is better in developed nations (solid colored bars) than developing nations (outlined bars).

3. Which is the bigger difference – urban vs. rural, or developed vs. developing nations?

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ANSWER: The discrepancy between rural and urban areas is larger than that between developed and developing nations.

4. Do you find your answer to question #3 surprising – or is it what you had expected?

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ANSWER: Your answer may vary. The instructors did find this surprising – our preconceived notion was that the major difference would be between developed and developing countries, and that access to water and sanitation in developed nations would be better than shown.

Access to clean water differs between rural and urban areas, and between developed and developing nations. In general, in rural areas, even in developed nations, access to water and sanitation lags behind that in urban areas. Globally, the areas with the poorest access to clean drinking water are in equatorial and sub-Saharan Africa, and parts of South America and southeast Asia (Figure 8).

One might imagine that access to clean water and sanitation would be strongly correlated with water-related illnesses and death. For example, compare the maps in Figures 8 and 9.

World map shows global access 2 clean water supply. African citizens have the least followed by south east asia and some arab countries
Figure 8: Global access to clean water supply by nation.
Source: World Health Organization, WHO
World map shows deaths attributed to water supply and sanitation. Most deaths in Africa, India followed by central and southern America
Figure 9: Deaths attributed to water supply and sanitation problems.
Source: World Health Organization, (WHO)

Learning Checkpoint

1. Compare the maps in Figures 8 and 9. Is there a correlation between access to improved water and water-related illness? Note two areas where there is a correlation, either positive or negative. See Figures 8 and 9 above.

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ANSWER: There are many areas where poor access to improved water sources coincides with high rates of death and disease from water-related illnesses. The most prominent are equatorial nations in Africa, parts of the Middle East, and to a lesser extent Indonesia and S. America (Ecuador, Peru). Likewise, there are numerous examples of regions with near-universal access to improved water (>90%) and the lowest rates of death and disease – notably North America, Australia, and much of Europe.

2. Based on Figure 8 and the distribution of water availability, do you think that these problems are related to water scarcity, or more related to water treatment and infrastructure?

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ANSWER: Although not a clear cut story everywhere, in some areas the problem seems unlikely to be water scarcity – for example in central Africa, where rainfall is plentiful, there are still high rates of death and disease. This suggests that the root of the problem is not scarcity. In other areas, like the Middle East (e.g. Egypt, Saudi Arabia), there is access to improved water, but the prevalence of disease – suggesting a possible link to water scarcity.