1. What are the contaminants
found in drinking water?
2. Where does drinking water
come from?
3. What if I have special
health needs?
4. How can I help protect
drinking water?
5. What are the health effects
of contaminants in drinking water?
What are the contaminants found in drinking
water?
There is no such thing as naturally pure water. In nature, all water
contains some impurities. As water flows in streams, sits in lakes,
and filters through layers of soil and rock in the ground, it dissolves
or absorbs the substances that it touches. Some of these substances
are harmless. In fact, some people prefer mineral water precisely
because minerals give it an appealing taste. However, at certain
levels minerals, just like man-made chemicals, are considered contaminants
that can make water unpalatable or even unsafe.
Some contaminants come from erosion of natural rock
formations. Other contaminants are substances discharged from factories,
applied to farmlands, or used by consumers in their homes and yards.
Sources of contaminants might be in your neighborhood or might be
many miles away. Your local water quality report tells which contaminants
are in your drinking water, the levels at which they were found,
and the actual or likely source of each contaminant.
Some ground water systems have established wellhead
protection programs to prevent substances from contaminating their
wells. Similarly, some surface water systems protect the watershed
around their reservoir to prevent contamination. Right now, states
and water suppliers are working systematically to assess every source
of drinking water and to identify potential sources of contaminants.
This process will help communities to protect their drinking water
supplies from contamination, and a summary of the results will be
included in future water quality reports.
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Where does drinking water come from?
A clean, constant supply of drinking water is essential to every
community. People in large cities frequently drink water that comes
from surface water sources, such as lakes, rivers, and reservoirs.
Sometimes these sources are close to the community. Other times,
drinking water suppliers get their water from sources many miles
away. In either case, when you think about where your drinking water
comes from, it's important to consider not just the part of the
river or lake that you can see, but the entire watershed. The watershed
is the land area over which water flows into the river, lake, or
reservoir.
In rural areas, people are more likely to drink ground
water pumped from a well. These wells tap into aquifers--the natural
reservoirs under the earth's surface--that may be only a few miles
wide, or may span the borders of many states. As with surface water,
it is mportant to remember that activities many miles away from
you may affect the quality of ground water.
Your annual drinking water quality report will tell
you where your water supplier gets your water from.
What if I have special health needs ?
People who have HIV/AIDS and
are undergoing chemotherapy, taking steroids, or for any other reason
have a weakened immune system may be more susceptible to microbial
contaminants, including Cryptosporidium, in drinking water. If you
or someone you know fall into one of these categories, talk to your
health care provider to find out if you need to take special precautions,
such as boiling your water.
Young children are particularly susceptible to the
effects of high levels of certain contaminants, including nitrate
and lead. To avoid exposure to lead, use water from the cold tap
for making baby formula, drinking, and cooking, and let the water
run for a minute or more if the water hasn't been turned on for
six or more hours. If your water supplier alerts you that your water
does not meet EPA's standard for nitrates and you have children
less than six months old, consult your health care provider. You
may want to find an alternate source of water that contains lower
levels of nitrates for your child.
How can I help protect drinking water?
Using the new information that is now available about
drinking water, citizens can both be aware of the challenges of
keeping drinking water safe and take an active role in protecting
drinking water. There are lots of ways that individuals can get
involved. Some people will help clean up the watershed that is the
source of their community's water. Other people might get involved
in wellhead protection activities to prevent the contamination of
the ground water source that provides water to their community.
These people will be able to make use of the information that states
and water systems are gathering as they assess their sources of
water.
People may also attend public meetings to ensure that
the community's need for safe drinking water
is considered in making decisions about land use. You may
wish to participate as your state and water system make funding
decisions. And all consumers can do their part to conserve water
and to dispose household chemicals.
What are the health effects of contaminants
in drinking water?
EPA has set standards for more than 80 contaminants that may occur
in drinking water and pose a risk to human health. EPA sets these
standards to protect the health of everybody, including vulnerable
groups like children. The contaminants fall into two groups according
to the health effects that they cause. Your water supplier will
alert you through the media, mail, or other means if there is a
potential acute or chronic health effect from compounds in the drinking
water. You may want to contact the supplier for additional information
specific to your area.
Acute effects occur within hours or days of the time
that a person consumes a contaminant. People can suffer acute health
effects from almost any contaminant if they are exposed to extraordinarily
high levels (as in the case of a spill). In drinking water, microbes,
such as bacteria and viruses, are the contaminants with the greatest
chance of reaching levels high enough to cause acute health effects.
The bodies of most people can fight off these microbial contaminants
the way they fight off germs, and these acute contaminants typically
don't have permanent effects. Nonetheless, higher can make people
ill, and can be dangerous for a person whose immune system is already
weak due to HIV/AIDS, chemotherapy, steroid use, or any other reason.
Chronic effects occur after people consume a contaminant
at levels over EPA's safety standards for many years. The drinking
water contaminants that can have chronic effects are chemicals (such
as disinfection by-products, solvents,
and pesticides), radionuclides (such as radium), and minerals (such
as arsenic). Drinking water contaminants can result in chronic conditions
like cancer, liver or kidney problems, or reproductive difficulties.
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