The first step
to protect your health and the health of your family is learning
about what may pollute your source of drinking water. Potential
contamination may occur naturally, or as a result of human activity.
What are Some Naturally Occurring Sources of Pollution?
- Microorganisms: Bacteria, viruses, parasites
and other microorganisms are sometimes found in water. Shallow
wells — those with water close to ground level — are
at most risk. Runoff, or water flowing over the land surface,
may pick up these pollutants from wildlife and soils. This is
often the case after flooding. Some of these organisms can cause
a variety of illnesses. Symptoms include nausea and diarrhea.
These can occur shortly after drinking contaminated water. The
effects could be short-term yet severe (similar to food poisoning)
or might recur frequently or develop slowly over a long time.
- Radionuclides: Radionuclides are radioactive
elements such as uranium and radium. They may be present in underlying
rock and ground water
- Radon: Radon is a gas that
is a natural product of the breakdown of uranium in the soil —
can also pose a threat. Radon is most dangerous when inhaled and
contributes to lung cancer. Although soil is the primary source,
using household water containing Radon contributes to elevated
indoor Radon levels. Radon is less dangerous when consumed in
water, but remains a risk to health.
- Nitrates and Nitrites: Although high nitrate
levels are usually due to human activities (see below), they may
be found naturally in ground water. They come from the breakdown
of nitrogen compounds in the soil. Flowing ground water picks
them up from the soil. Drinking large amounts of nitrates and
nitrites is particularly threatening to infants (for example,
when mixed in formula).
- Heavy Metals: Underground rocks and soils
may contain arsenic, cadmium, chromium, lead, and selenium. However,
these contaminants are not often found in household wells at dangerous
levels from natural sources.
- Fluoride: Fluoride is helpful in dental health,
so many water systems add small amounts to drinking water. However,
excessive consumption of naturally occurring fluoride can damage
bone tissue. High levels of fluoride occur naturally in some areas.
It may discolor teeth, but this is not a health risk.
What Human Activities Can Pollute Ground Water?
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Septic tanks
are designed to have a “leach field” around them
— an area where wastewater flows out of the tank.
This wastewater can also move into the ground
water. |
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Bacteria and Nitrates: These pollutants are found
in human and animal wastes. Septic tanks can cause bacterial and
nitrate pollution. So can large numbers of farm animals. Both
septic systems and animal manures must be carefully managed to
prevent pollution. Sanitary landfills and garbage dumps are also
sources. Children and some adults are at extra risk when exposed
to water-born bacteria. These include the elderly and people whose
immune systems are weak due to AIDS or treatments for cancer.
Fertilizers can add to nitrate problems. Nitrates cause a health
threat in very young infants called “blue baby” syndrome.
This condition disrupts oxygen flow in the blood.
- Concentrated Animal Feeding Operations (CAFOs):
The number of CAFOs, often called “factory farms,”
is growing. On these farms thousands of animals are raised in
a small space. The large amounts of animal wastes/manures from
these farms can threaten water supplies. Strict and careful manure
management is needed to prevent pathogen and nutrient problems.
Salts from high levels of manures can also pollute ground water.
- Heavy Metals: Activities such as mining and
construction can release large amounts of heavy metals into nearby
ground water sources. Some older fruit orchards may contain high
levels of arsenic, once used as a pesticide. At high levels, these
metals pose a health risk.
- Fertilizers and Pesticides: Farmers use fertilizers
and pesticides to promote growth and reduce insect damage. These
products are also used on golf courses and suburban lawns and
gardens. The chemicals in these products may end up in ground
water. Such pollution depends on the types and amounts of chemicals
used and how they are applied. Local environmental conditions
(soil types, seasonal snow and rainfall) also affect this pollution.
Many fertilizers contain forms of nitrogen that can break down
into harmful nitrates. This could add to other sources of nitrates
mentioned above. Some underground agricultural drainage systems
collect fertilizers and pesticides. This polluted water can pose
problems to ground water and local streams and rivers. In addition,
chemicals used to treat buildings and homes for termites or other
pests may also pose a threat. Again, the possibility of problems
depends on the amount and kind of chemicals. The types of soil
and the amount of water moving through the soil also play a role.
- Industrial Products and Wastes: Many harmful
chemicals are used widely in local business and industry. These
can become drinking water pollutants if not well managed. The
most common sources of such problems are:
- Local Businesses: These include nearby
factories, industrial plants, and even small businesses such
as gas stations and dry cleaners. All handle a variety of
hazardous chemicals that need careful management. Spills and
improper disposal of these chemicals or of industrial wastes
can threaten ground water supplies.
- Leaking Underground Tanks & Piping:
Petroleum products, chemicals, and wastes stored in underground
storage tanks and pipes may end up in the ground water. Tanks
and piping leak if they are constructed or installed improperly.
Steel tanks and piping corrode with age. Tanks are often found
on farms. The possibility of leaking tanks is great on old,
abandoned farm sites. Farm tanks are exempt from the EPA rules
for petroleum and chemical tanks.
- Landfills and Waste Dumps: Modern landfills
are designed to contain any leaking liquids. But floods can
carry them over the barriers. Older dumpsites may have a wide
variety of pollutants that can seep into ground water.
- Household Wastes: Improper disposal of many
common products can pollute ground water. These include cleaning
solvents, used motor oil, paints, and paint thinners. Even soaps
and detergents can harm drinking water. These are often a problem
from faulty septic tanks and septic leaching fields.
- Lead & Copper: Household plumbing materials
are the most common source of lead and copper in home drinking
water. Corrosive water may cause metals in pipes or soldered joints
to leach into your tap water. Your water’s acidity or alkalinity
(often measured as pH) greatly affects corrosion. Temperature
and mineral content also affect how corrosive it is. They are
often used in pipes, solder, or plumbing fixtures. Lead can cause
serious damage to the brain, kidneys, nervous system, and red
blood cells. The age of plumbing materials — in particular,
copper pipes soldered with lead — is also important. Even
in relatively low amounts these metals can be harmful. EPA rules
under the Safe Drinking Water Act limit lead in drinking water
to 15 parts per billion. Since 1988 the Act only allows “lead
free” pipe, solder, and flux in drinking water systems.
The law covers both new installations and repairs of plumbing.
- Water Treatment Chemicals: Improper handling
or storage of water-well treatment chemicals (disinfectants, corrosion
inhibitors, etc.) close to your well can cause problems.
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