, fingers, flies, fields, fluids, food), showing pathways of
fecal–oral disease transmission. The vertical blue lines show barriers:
toilets,
safe water,
hygiene and
handwashing. The
World Health Organization considers access to safe drinking-water a basic human right.
Contaminated water is estimated to result in more than half a million deaths per year. According to the WHO, the most common
diseases linked with poor water quality are
cholera,
diarrhea,
dysentery,
hepatitis A,
typhoid, and
polio. One of the main causes for contaminated drinking water in developing countries is lack of sanitation and poor hygiene. For this reason, the quantification of the
burden of disease from consuming contaminated drinking water usually looks at water, sanitation and hygiene aspects together. The
acronym for this is
WASH - standing for
water, sanitation and hygiene.
Diarrhea, malnutrition and stunting and
hygiene.
Consumption of contaminated groundwater Sixty million people are estimated to have been poisoned by well water contaminated by excessive
fluoride, which dissolved from granite rocks. The effects are particularly evident in the bone deformations of children. Similar or larger problems are anticipated in other countries including China, Uzbekistan, and Ethiopia. Although helpful for dental health in low dosage, fluoride in large amounts interferes with bone formation. Long-term consumption of water with high fluoride concentration (> 1.5 ppm F) can have serious undesirable consequences such as
dental fluorosis, enamel mottle and
skeletal fluorosis, bone deformities in children. Fluorosis severity depends on how much fluoride is present in the water, as well as people's diet and physical activity. Defluoridation methods include membrane-based methods, precipitation, absorption, and electrocoagulation. Natural
arsenic contamination of groundwater is a
global threat with 140 million people affected in 70 countries globally.
Examples of poor drinking water quality incidents Some examples of water quality problems with drinking water supplies include: • In 1854, a
cholera outbreak in London's Soho district was identified by
John Snow as originating from contaminated water from the Broad Street pump. This was a founding event of the science of
epidemiology. •
Contamination of groundwater with arsenic in Bangladesh; the largest-scale mass poisoning of a population (began in the 1970s–1980s, officially recognized in 1993) •
Hinkley groundwater contamination (Chromium-6 contamination of private groundwater wells in Hinkley, California, United States (settled in 1996). •
Walkerton E. coli outbreak (
Escherichia coli O157:H7 and
Campylobacter contamination of water supply in Walkerton, Ontario, Canada in 2000). In 2000, an
E. coli outbreak occurred in
Walkerton, Ontario, Canada. Seven people died from drinking contaminated water. Hundreds suffered from the symptoms of the disease. •
Flint water crisis (lead and
Legionella contamination of water supply in Flint, Michigan, United States, started in 2014) •
Jackson, Mississippi water crisis, United States (2022) • In 1987, a
cryptosporidiosis outbreak in western Georgia • In 1993,
Milwaukee Cryptosporidium outbreak • In 1998, an outbreak of
typhoid fever in northern Israel, which was associated with the contaminated municipal water supply • In 1997, 369 cases of
cryptosporidiosis occurred, caused by a contaminated fountain in the Minnesota zoo. Most of the sufferers were children • In 1998, a non-chlorinated municipal water supply was blamed for a
campylobacteriosis outbreak in northern Finland • In 2000, a
gastroenteritis outbreak that was brought by a non-chlorinated community water supply, in southern Finland • In 2004, contamination of the community water supply, serving the Bergen city centre of Norway, was later reported after the outbreak of waterborne
giardiasis • In 2007, contaminated drinking water was pinpointed which had led to the outbreak of gastroenteritis with multiple
aetiologies in Denmark Examples of chemical contamination include: • In 1988 many people were poisoned in
Camelford, when a worker put 20 tonnes of
aluminium sulphate coagulant in the wrong tank. • In 1993 a fluoride poisoning outbreak resulting from overfeeding of fluoride, in Mississippi. • In 2007 the water supply of
Spencer, Massachusetts became contaminated with excess
sodium hydroxide (lye) when its treatment equipment malfunctioned. • In 2019 electric
transformer oil entered the water supply for the city of
Uummannaq in Greenland. A cargo ship in harbour was able to maintain a minimum supply to the city for two days until the mains supply was restored and flushing of all the pipework was started. ==Treatment==