Standards Of Water For Human Consumption

Clean water is one of the most important needs of our bodies. It is a sad fact
that something as essential to life as clean drinking water can no longer be
granted to us. According to research articles and news, most tap and well
water now are not safe for drinking due to heavy industrial and environmental pollution. We have reached to a point that, all sources of our drinking water,
including municipal water systems, wells, lakes, rivers, and even glaciers,
contain some level of contamination.

Standards Of Water For Human Consumption

Sources of Contaminants in Drinking Water

Several contaminants occur in nature that may present a health risk if they are
found in drinking water. The various pollutant /contaminants are bacteria,
viruses, uranium, radium, nitrate, arsenic, chromium and fluoride. 
sources of contamination are a result of human activity such as manufacturing
or agriculture, or individual misuse. The following activities may cause
harmful microorganisms and chemicals to enter the well water owner’s water
• Leakage from waste disposal, treatment, or storage sites. 
• Discharges from factories, industrial sites, or sewage treatment facilities. 
• Leaching from aerial or land application of pesticides and fertilizers on
yards or fields. 
• Accidental chemical spills. 
• Leakage from underground storage tanks.

Contamination due to Harmful Microorganisms

The most common and widespread health risk associated with drinking water
is microbial contamination, either directly or indirectly, by human or animal
excreta and micro-organisms contained in faeces.
The pathogenic agents involved include bacteria, viruses and protozoa, which
may cause diseases that vary in severity from mild gastroenteritis to severe
and sometimes fatal diarroea, dysentry, hepatitis or typhoid fever. 
Most of
them are widely distributed through out the world. Fecal contamination of
drinking water is only one of the several faeco-oral mechanisms by which they
can be transmitted from one person to another, or in some cases, from animal
to people. 
The human pathogens potentially transmitted in drinking water are
Bacteria viz. Escherichia coli,Salmonella, Shigella, Vibrio cholera, Yersinia
enterocolitica, Campylobacter jejuni; viruses viz, Adenoviruses, Enterovirus,
Hepatitis A, Hepatitis E, Norwalk virus, Rotavirus, and small round viruses;
The parasites, Giardia, Cryptosporidium, Entamoeba histolytica and
Drancunculus. The removal of these agents from drinking water should be
given top priority.
Apart from the above said pathogens of high health significance, there are
some more organisms that are present in environment and not normally
regarded as pathogen, may caue disease opportunistically. When such
organisms are present in water they cause infection predominantly among
people whose local or general defence mechanisms are impaired. 
Those most
likely to be at risk include the very old, the very young and patients in the
hospitals,e.g. those with burns or immunosuppressive therapy, and those
suffering from acquired immunodeficiency syndrome(AIDS). Water used by
such patients for drinking or bathing, if it contains excessive number of these
agents, may produce a variety of infections involving the skin and mucous
membrane of the eye, ear, nose and throat. 
Pseudomonas, Flavobacterium,
Acinetobacter, Klebsiella and Serratia are examples of such opportunistic
pathogens. Legionella infects the lung. These organisms while clearly of
medical importance, acquire public health significance only under certain
conditions. There removal from drinking water may therefore be given
moderate priority

Drinking Water Standards

Microorganisms, including pathogenic organisms, may enter water supplies at
every stage of the collection and distribution cycle. Emphasis should be
placed on the need for an active watershed protection program, including an
emergency plan for responding to major pollution events such as spills or
Drinking water standards
Let us know in brief about the above contaminants

Coliform bacteria

These are common in the environment and are generally not harmful.
However, the presence of these bacteria in drinking water is usually a result of
a problem with the treatment system or the pipes which distribute water, and
indicates that the water may be contaminated with germs that can cause
Fecal Coliform and E.Coli are bacteria whose presence indicates that
the water may be contaminated with human or animal wastes. Microbes in
these wastes can cause short-term effects, such as diarrhoea, cramps, nausea,
headaches, or other symptoms.
Turbidity has no health effects. However, turbidity can interfere with
disinfection and provide a medium for microbial growth. Turbidity may
indicate the presence of disease causing organisms. These organisms include
bacteria, viruses, and parasites that can cause symptoms such as nausea,
cramps, diarrhoea, and associated headaches.
Cryptosporidium is a parasite that enters lakes and rivers through sewage and
animal waste. It causes cryptosporidiosis, a mild gastrointestinal disease.
However, the disease can be severe or fatal for people with severely weakened
immune systems.
Giardia lamblia is a parasite that enters lakes and rivers through sewage and
animal waste. It causes gastrointestinal illness (e.g. diarrhoea, vomiting,
Hence, it is important that our drinking water does not contain any
concentration of microorganisms, parasites or any other substance which
constitutes a potential human health risk and it meets the minimum
requirements (microbiological and chemical parameters and those relating to
radioactivity) laid down by the directives.

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