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Frequently Asked Question (FAQ)
How Safe Is
Your Drinking Water?
Nationwide, drinking water systems have spent Crores of rupees
to build drinking water treatment and distribution systems,
and they spend Lakhs of rupees every year to operate and maintain
them.
There is a network of government agencies whose job is to ensure
that public water supplies are safe. However, problems with
local drinking water can, and do, occur.
All sources of drinking water contain some naturally occurring
contaminants. Because water is the universal solvent, many materials
are easily dissolved upon contact. At low levels, these contaminants
generally are not harmful in our drinking water. Removing all
contaminants would be extremely expensive and in nearly all
cases would not provide greater protection of health. A few
of the naturally occurring substances may actually improve the
taste of drinking water and may have nutritional values at low
levels. 
What Problems Can Occur?
As development in our modern society increases, there are growing
numbers of threats that could contaminate drinking water. Suburban
sprawl has encroached upon once-pristine watersheds, bringing
with it all of the by-products of our modern life style. Actual
events of serious drinking water contamination occur infrequently,
and typically not at levels posing near-term health concern.
Nonetheless, with the threats of such events increasing, we
cannot take drinking water safety for granted. Greater vigilance
by you, your water supplier, and your government is vital to
ensure that such events do not occur in your water supply.
Microbiological and chemical contaminants can enter water supplies.
These materials can be the result of human activity or can be
found in nature. For instance, chemicals can migrate from disposal
sites and contaminate sources of drinking water. Animal wastes
and pesticides may be carried to lakes and streams by rainfall
runoff or snow melt. Human wastes may be discharged to receiving
waters that ultimately flow to water bodies used for drinking
water. Coliform bacteria from human and animal wastes may be
found in drinking water if the water is not properly treated
or disinfected. These bacteria are used as indicators that other
harmful organisms may be in the water.
The potential for health problems from drinking water is illustrated
by localized outbreaks of water-borne disease. Many of these
outbreaks have been linked to contamination by bacteria or viruses,
probably from human or animal waste.
Nitrate in drinking water at levels above the national standard
poses an immediate threat to young children. Excessive levels
can result in a condition known as "blue baby syndrome."
If untreated, the condition could be fatal.
Boiling water contaminated with nitrate increases the nitrate
concentration and the potential risk. Persons worried about
nitrate should talk with their doctor about alternatives to
using boiled water in baby formula.
Naturally occurring contaminants also are being found in drinking
water. For example, the radioactive gas radon-222 occurs in
certain types of rock and can get into ground water. People
can be exposed to radon in water by drinking it, while showering,
or when washing dishes. The primary source of exposure to radon
in the home is radon seeping out of the soil and into the basement
air.
Where Can
You Get More Information About Your Water?
Information on water quality in your area is available from
several sources, including your local public health department
and your water supplier. You can determine whom to contact by
checking your water bill or by calling your local town hall.
State agencies also can provide extensive information on your
water supply and its quality. Each state has a department responsible
for drinking water quality.
Who Makes
Sure That Your Drinking Water Supply Is Safe ?
Local governments, public water systems, the states, work together
towards the goal of ensuring that all public water supplies
are safe. For households on private wells, state and local health
departments usually have some standards for the drinking water,
but it is generally up to the homeowner to maintain the quality
of the drinking water.
Local governments have a direct interest in protecting the quality
of their drinking water source, be it ground water or surface
water. They may be responsible for overseeing land uses that
can affect the quality of untreated source water. Public water
systems have a responsibility to maintain sound treatment works
and water distribution networks. They are responsible for ensuring
that the water they supply does not contain contaminants at
levels higher than the law allows.
Boil Water Notices
When microorganisms such as those that indicate fecal
contamination are found in drinking water, water suppliers
may be required to issue "boil water notices."
Boiling water kills the organisms that can cause disease.
Therefore, the notices serve as a precaution for the
public.
What Do
You Need To Know To Protect Your Private Drinking Water Supply?
Approximately 10 % Indian citizens rely on their own private
drinking water supplies. Most of these supplies are drawn from
ground water through wells, but some households also use water
from streams or cisterns. These households must take special
precautions to ensure the protection and maintenance of their
drinking water supplies. How Can You Test The Quality Of Your
Private Drinking Water Supply? Private water supplies should
be tested annually for nitrate and coliform bacteria to detect
contamination problems early. They should be tested more frequently
and for more potential contaminants, such as radon or pesticides,
if a problem is suspected. Many laboratories are available to
test water quality. Lists of laboratories certified by your
state may be available from your local or state public health
department. Some local health departments also test private
water for free. Phone numbers for your local, county, or state
health department are available under the government listings
in your phone book. How Can You Protect Your Private Water Supply?
You can protect your water supply by carefully managing activities
near the water source. For households using a domestic well,
this includes keeping contaminants away from sinkholes and the
well itself. Hazardous chemicals also should be kept out of
septic systems.
water-borne disease Disease associated with poor water supply.
In the Third World four-fifths of all illness is caused by water-borne
diseases, with diarrhea being the leading cause of childhood
death. Malaria, carried by mosquitoes dependent on stagnant
water for breeding, affects 400 million people every year and
kills 5 million. Polluted water is also a problem in industrialized
nations, where industrial dumping of chemical, hazardous, and
radioactive wastes causes a range of diseases from headache
to cancer.
Protecting Your Ground Water Supply· Periodically inspect exposed
parts of the well for problems such as: - cracked, corroded,
or damaged well casing - broken or missing well cap - settling
and cracking of surface seals. · Slope the area around the well
to drain surface runoff away from the well. · Install a well
cap or sanitary seal to prevent unauthorized use of, or entry
into, the well. · Disinfect drinking water wells at least once
per year with bleach or hypochlorite granules, according to
the manufacturers directions. · Have the well tested once a
year for coliform bacteria, nitrates, and other constituents
of concern. · Keep accurate records of any well maintenance,
such as disinfection or sediment removal, that may require the
use of chemicals in the well. · Hire a certified well driller
for any new well construction, modification, or abandonment
and closure. · Avoid mixing or using pesticides, fertilizers,
herbicides, degreasers, fuels, and other pollutants near the
well. · Do not dispose of wastes in dry wells or in abandoned
wells. · Do not cut off the well casing below the land surface.
· Pump and inspect septic systems as often as recommended by
your local health department. · Never dispose of hazardous materials
in a septic system.
Where Does
Your Drinking Water Come From ?
Drinking water comes from surface water and ground water. Large-scale
water supply systems tend to rely on surface water resources,
and smaller water systems tend to use ground water.
Surface water includes rivers, lakes, and reservoirs. Ground
water is pumped from wells that are drilled into aquifers. Aquifers
are geologic formations that contain water. The quantity of
water in an aquifer and the water produced by a well depend
on the nature of the rock, sand, or soil in the aquifer where
the well withdraws water. Drinking water wells may be shallow
(50 feet or less) or deep (more than 1,000 feet). Your water
utility or your public works department can tell you the source
of your public drinking water supply.
Public & Private Water Supply
System : -
Public water supply system is one that serves piped water to
several homes round the year. Water that does not come from
a public water supply, and which serves one or only a few homes,
is called private supply.
How Does
Water Get To Your Taps?
In a typical community water supply system, water is
transported under pressure through a distribution network of
buried pipes. Smaller pipes, called house service lines, are
attached to the main water lines to bring water from the distribution
network to your house. In many community water supply systems,
water pressure is provided by pumping water up into storage
tanks that store water at higher elevations than the houses
they serve. The force of gravity then "pushes" the
water into your home when you open your tap. Houses on a private
supply usually get their water from a private well. A pump brings
the water out of the ground and into a small tank within the
home, where the water is stored under pressure.
How Do Public Water Suppliers Treat My Water To Make It Safe?
Water suppliers use a variety of treatment processes to remove
contaminants from drinking water. These individual processes
may be arranged in a "treatment train" to remove undesirable
contaminants from the water. The most commonly used processes
include filtration, flocculation and sedimentation, and disinfection.
Some treatment trains also include ion exchange and adsorption.
A typical water treatment plant would have only the combination
of processes needed to treat the contaminants in the source
water used by the facility. If you want to know what types of
treatment are used for your water supply, contact your local
water supplier or public works department.
How Can
You Help To Protect Your Drinking Water Supply?
Drinking water protection is a shared responsibility, involving
water suppliers, local and state governments, business, and
individuals. We all have an important role to play, and as private
citizens we have many opportunities. Environmental protection
activities such as watershed protection projects are taking
place across the Nation. Clean and healthy watersheds are vital
to safe drinking water.
Other opportunities to be involved in drinking water protection
are discussed in the rest of this section.
Sole source aquifer protection programs also protect ground
water supplies, but usually over a much larger area than that
covered by wellhead protection programs. They focus on government-funded
projects that may affect the aquifer.
Source water protection should be a critical part of all community
water programs. In the past, water suppliers used most of their
resources to treat water from rivers, lakes, and underground
sources of drinking water before supplying it to our homes as
drinking water. Now, we understand that if we place greater
emphasis on protecting our sources of drinking water, the need
for treatment can be reduced.
The general components of a source
water protection program includes:
- Delineation: Identifying the area of land that water passes
through to reach the drinking water intake.
- Contaminant source inventory: Mapping the locations of potential
sources of drinking water contamination.
- Source water protection area management: Using regulatory
controls, such as zoning or health ordinances, or non regulatory
controls, such as technical assistance to businesses and public
education, to keep contaminants out of drinking water supplies.
- Contingency planning: Plan special actions in case a sudden
event (for instance, a flood or spill) occurs that threatens
the drinking water supply.
How Can You Get Involved To Protect Water Supplies?
Many communities are in the process of implementing source water
protection programs. Your local water supplier can tell you
whether your community has a source water protection program.
Source water protection works by involving all members of the
community. Citizens can voice their support for controlling
how land is used near drinking water intakes.
Citizens can also educate their neighbors about the danger that
household chemicals pose to drinking water supplies. Many communities
sponsor household hazardous waste disposal days to promote proper
handling of waste paints and thinners, pesticides, used oil,
and other hazardous materials. Your state or local environmental
agency should have information about such programs in your community.
Successful Source Water Protection Elkhart, Indiana began developing
a source water protection program in the late 1980s, after being
forced to close one of its drinking water wellfields when dangerous
chemical solvents were found in the drinking water supply. Officials
in Elkhart realized that they needed an efficient way to inventory
and map all of the potential sources of contamination that could
reach their new drinking water supply. They discovered that
retired senior volunteers are an excellent resource for conducting
the inventories. By working with the Service Corps of Retired
Executives and the American Association of Retired Persons,
Elkhart recruited 20 senior volunteers, from a list of over
400 potential volunteers, to conduct the inventories. Working
with city staff, the senior volunteers visited homes and businesses
throughout Elkhart and mapped 280 potential contaminant sources
for management. Management controls include zoning/land use
control and technical assistance. So far, Elkhart has been successful
in keeping its drinking water sources clean.
water
is
a chemical compound of hydrogen and oxygen elements, H2O. It
can exists as a solid (ice), liquid (water), or gas (water vapour).
Water is the most common element on Earth and vital to all living
organisms. It covers 70% of the Earth's surface, and provides
a habitat for large numbers
of aquatic organisms. It is the largest constituent of all living
organisms - the human body consists of about 65% water. Pure
water is a colorless, odorless, tasteless liquid which freezes
at 0ºC/32ºF, and boils at 100ºC/212ºF. Natural water in the
environment is never pure and always
contains a variety of dissolved substances. Some 97% of the
Earth's water is in the oceans; a further 2% is in the form
of snow or ice, leaving only 1% available as fresh water for
plants and animals. The recycling and circulation of water through
the biosphere is termed the water cycle,
or `hydrological cycle´; regulation of the water balance in
organisms is termed osmoregulation.
The water cycle
Water occurs on the Earth's surface as standing
water in oceans and lakes, as running water in rivers and streams,
as rain, and as water vapour in the atmosphere. Together these
sources comprise the hydrosphere which is in a constant state
of flux as water vapour condenses to fall as rain, and after
flowing through rivers and streams into lakes and oceans is
returned to the atmosphere by evaporation. And so the cycle
continues. Since the hydrological cycle is a closed system,
the amount of water in the Earth's hydrosphere is constant.
The cycle is powered by solar radiation which provides the energy
to maintain the flow through the processes of evaporation, transpiration,
precipitation, and runoff.
Osmoregulation
Water is very important to living organisms: it
helps cells to maintain their form; as a solvent, it dissolves
salts, sugars, proteins, and many other substances that are
involved in metabolism and the digestion of food; it enables
the transportation of bodily wastes, and the maintenance of
a stable body temperature through perspiration and evaporation.
But too much water can be dangerous. The process that maintains
an equable balance of water content in an organism is osmoregulation.
Organisms gain water in a number of ways - by osmosis, in food,
and by
respiration. They lose water by evaporation, in urine, and by
osmosis. In humans, the kidneys play a very important role in
the regulation of water balance.
Water makes up 60-70% of the human body or about 40 l/70 pt
of which 25 l/53 pt are inside the cells, 15 l/26 pt outside
(12 l/21 pt in tissue fluid, and 3 l/5 pt in blood plasma).
A loss of 4 l/7 pt may cause hallucinations; a loss of 8-10
l/14-18 pt may cause death. About 1.5 l/2.6pt a day are lost
through breathing, perspiration, and faces, and the additional
amount lost in urine is the amount needed to keep the balance
between input and output. In temperate climates, people cannot
survive more than five or six days without water, or two or
three days in a hot environment. A family of two adults and
two children uses approximately 200 l/ 350 pt per day (UK figures).
The British water industry was privatized in 1989, and in 1991
the UK was taken to court for failing to meet EC drinking-water
standards on nitrate and pesticide levels.
Properties of
water
With a relative molecular mass of 18, water has unusual properties
for a molecule of its size, and many of these properties have
biological significance. It is a polar molecule with a slight
positive charge at one end and a slight negative charge at the
other. The oxygen molecule has a negative charge and attracts
the positively charged hydrogen atoms of other water molecules,
with the result that hydrogen bonds are formed between the water
molecules holding them together. This makes water a very good
solvent for other polar molecules and ionic substances which
become more reactive in solution. Thus it provides the medium
for metabolic reactions in organic cells and is vital in the
transport of substances around the bodies of organisms. For
example, food substances, hormones, and urea are dissolved and
transported in blood plasma which consists of over 90% water.
Water has a high heat capacity, which means that it requires
large amounts of heat energy to produce small rises in temperature.
Consequently, temperature changes in water are usually quite
small, and this is important in cells where metabolic reactions
are controlled by enzymes; externally, it also provides a fairly
constant environment for aquatic organisms. A great deal of
heat is required to change water from its liquid state to vapour
and this is important in temperature control in mammals. When
the body becomes overheated, the animal sweats; thus the heat
used for the vaporization of water in sweat is lost from the
body, thereby cooling it.
In liquid form, water cannot be compressed; when frozen, it
expands by 1/11 of its volume. It has its maximum density at
4ºC/39.2ºF (one cubic centimeter of water has a mass of one
gram forming the unit of specific gravity). When cooled below
this temperature, the density of water
decreases so that ice floats on the surface. This has been an
important factor for the evolution of life on Earth, particularly
in Arctic and temperate regions.
The individual molecules of water have great attraction for
one another, producing high surface tension, and this is important
in the conduction of water through the xylem tissue of plants.
Plants require water to carry nutrients from the root zone into
the body of the plant, to enable photosynthesis to take place,
and to aid transpiration.
Human impact
Water is not evenly distributed across the
planet's surface - in some places there is too little, in others
too much. Expanding populations are making greater and greater
demands on supplies, although human impact on the water cycle
is mainly in the runoff sector, with water being diverted for
domestic, industrial, and agricultural uses. However, modern
society interferes with almost all aspects of the cycle: agricultural
and forestry practices disrupt evaporation and transpiration;
boreholes and wells allow access to the groundwater system;
and the construction of dams and reservoirs creates additional
storage. Since the cycle is a closed system, human activities
cannot deplete the overall supply, but excess withdrawal from
the runoff or groundwater sectors can create localized shortages
of water. Most human uses involve only short- term withdrawal
from the system, but often the water is returned with its quality
greatly impaired by pollutants. Pesticides and fertilizers used
in agriculture and weed killers from road verges are washed
into ground water used for public water supplies; industrial
chemicals get into drinking water from rivers.
Human consumption
The major demand is for fresh water, but the proportion
of fresh water to saline is very small - only 3 %of the total
volume of the hydrosphere. According to two UN reports in January
1997, large areas of the globe will start running critically
short of water in the next 30 years. Total worldwide water consumption
has been growing at 2.5% a year, roughly twice as fast as the
population, and by 1997 it had reached 4,200 cubic kilometers
annually. During the 20th century,
water consumption has risen six fold and, as many rivers cross
national boundaries, there is a danger that growing demands
for this resource in the future could lead to conflict.
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