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Effects of Poor Water Quality

Poor water quality continues to pose a major threat to human health. Diarrhoeal disease alone amounts to an estimated 4.1 % of the total DALY global burden of disease and is responsible for the deaths of 1.8 million people every year (WHO, 2004). It was estimated that 88% of that burden is attributable to unsafe water supply, sanitation and hygiene and is mostly concentrated on children in developing countries.
A significant amount of disease could be prevented especially in developing countries through better access to safe water supply, adequate sanitation facilities and better hygiene practices.

What may by Causing Illness in the Water

Pathogenic organisms

One of the most widespread and serious classes of water quality contaminants, especially in areas where access to safe, clean water is limited, is pathogenic organisms: bacteria, protozoa, and viruses. These organisms pose one of the leading global human health hazards. The greatest risk of microbial contamination comes from consuming water contaminated with pathogens from human or animal feces.
In addition to microorganisms introduced into waters through human or animal fecal contamination, a number of pathogenic microorganisms are free-living in certain areas or are, once introduced, capable of colonizing a new environment. These free-living pathogens, like some Vibrio bacterial species and a few types of amoebas, can cause major health problems in those exposed, including intestinal infections, amoebic encephalitis, amoebic meningitis, and occasional death (WHO 2008).
Viruses and protozoa also pose human health risks, including Cryptosporidium and Giardia, Guinea worm, and others.

Trace Metals

Trace metals, such as arsenic, zinc, copper, and selenium, are naturally found in many different waters. Some human activities like mining, industry, and agriculture can lead to an increase in the mobilization of these trace metals out of soils or waste products into fresh waters. Even at extremely low concentrations, such additional materials can be toxic to aquatic organisms or can impair reproductive and other functions.
  • For a complete list of trace metal and chemical hazards in drinking water, please see WHO Index.

Effects of Poor Water Quality

Waterborne diseases

Waterborne diseases include those for which water is the agent of transmission, particularly those pathogens transmitted from excreta to water to humans. These include most of the enteric and diarrheal diseases caused by bacteria, parasites and viruses, such as cholera, Giardia, typhoid, and rotaviruses. Drinking water contaminated by human or animal excreta is the main cause of water-related diseases. The first such diseases identified were typhoid and cholera, and both remain a serious problem in many regions of the world.
The most common causes of severe diarrheal disease include Rotavirus, Pathogenic E. coli, Campylobacter jejuni, and protozoan parasites. The leading cause of severe diarrhea in children is Rotavirus, and almost every child who reaches the age of five will have an episode of rotavirus gastroenteritis (UNICEF 2008). Epidemic diarrheal diseases are caused by Shigella and Vibrio cholera. Both are highly infectious and are prone to severe epidemics. There are also non-diarrheal waterborne diseases including Typhoid fever, which causes 600,000 deaths per year.
Two forms of Hepatitis, Hepatitis A and E, are waterborne diseases caused by ingestion of fecally contaminated water.

Water-based diseases

Water-based diseases come from hosts that either live in water or require water for part of their life cycle. These diseases are passed to humans when they are ingested or come into contact with skin. The two most widespread examples in this category are schistosomiasis, which results from contact with snails that serve as hosts, and dracunculiasis (Guinea worm), which results from ingesting contaminated host zooplankton.
There are about 160 million people in 74 countries who are infected with schistosomiasis, a tenth of whom suffer severe effects (UNICEF 2008), and schistosomiasis could be responsible for 200,000 deaths in sub-Saharan Africa alone. The disease continues to spread where irrigation projects produce habitat that favors the host snails. Major outbreaks of schistosomiasis often follow the construction of large dams. In the Sudan, the construction of SennĂ¢r dam led to the infection of nearly the entire nearby population.
  • For a list of Major Water-Based Diseases and other Water Related Diseases, please see The Health Dimension

High Concentrations of Nutrients

High concentrations of nutrients can pose serious risks to human health. The potential health effects of nitrates are numerous and include methemoglobinemia (infant blue baby syndrome); cancers; thyroid disruptions; and birth defects. Blue-baby syndrome occurs when the oxygencarrying capacity of hemoglobin is blocked by nitrites (caused by the conversion of nitrates in the stomach), leading to oxygen deprivation and suffocation. Infants are especially susceptible because their stomachs easily convert nitrates to nitrites.
High levels of nutrients like nitrates have also been linked to stomach cancer and negative reproductive outcomes.

Effects of Poor Water Quality on People Living With HIV/AIDS

The effects of water quality are amplified for people living with HIV/AIDS (PLWHA). Diarrheal diseases are easier to acquire and reduce the effectiveness of any drug treatment a person may be taking. Below are a few well-documented power points regarding the importance of safe water for PLWHA that can provide powerful talking points for sharing the importance of safe water for general advocacy and donor purposes as well as an approach to assessing communities that may have a high incidence of HIV/AIDs residents. These studies were written by the Center for Affordable Sanitation Technologies (CAWST).

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