What Human Activities Can Pollute Ground Water?
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:
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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.
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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.
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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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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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