Radon is a naturally occurring radioactive element that can be found in
soil, underground water, and outdoor air. Some of the properties of this gas
include being odorless, tasteless, and colorless. The concentrations vary
throughout the country depending on the types of rocks that are found in the
soil. Exposure over prolonged periods of time to radon decay products has been
associated with an increased risk of lung cancer.(3) The EPA describes an
elevated concentration as being at or above their suggested guidelines of 4pCi/l
(pico Curies per liter, used as a radiation unit of measure for radon).
Exposures below this level may create a risk of lung cancer, farther reductions
to lower levels may be too difficult or even impossible to achieve.(4)

Radon enters buildings through: exposed soil in crawl spaces, through
cracks, openings in floors, and through below grade walls and floors. This is
the primary source of elevated radon levels in buildings.(5) Outdoor air
contains radon, but it is in extremely low concentrations therefore it is not a
health hazard. Some wells contain water that has radon dissolved in it. This
can be a hazard if the water is agitated or heated, allowing the gas to escape
and elevate the levels that are in the building.(6)

Health Risk

The Surgeon General's office reports that indoor radon gas is a national
health problem. This gas causes thousands of deaths every year.(7) These
deaths are a result of lung cancer, which is caused by the radioactive particles
that make up the gas.(8) The likelihood of getting lung cancer from radon
depends on: the concentration that you are exposed to, the amount of time that
you are exposed, and whether you smoke or not. The radioactive particles are
inhaled when we breathe, and become trapped in the lungs. Once in the lungs
they release small amounts of energy that can damage the tissue of the lungs
which in turn can cause cancer.(9)

Radon is the second leading cause of lung cancer, with smoking being
number one according to the Surgeon Generals office.(10) Smoking greatly
increases the risk of getting lung cancer. Non smokers are allot less likely to
get lung cancer from radon than smokers.(11) Radon is a big problem because a
majority of the population spends most of its time indoors. This increases the
amount of time that they are exposed, and the likelihood that they will get lung

Where Radon Originates

Radon is created by the radioactive decay of uranium found in rocks,
soil, and water. Uranium and its by products of decay, namely radon are
abundant and are constantly being generated.(13) Radon is capable of easily
traveling through rocks and soil.(14) The gas is also found dissolved in water,
due to decay in the soil or rock below.(15)

Radon in Water

The risk from radon in water is much lower than the risk from radon in
air. This is because the water must be heated or agitated to release the gas.
This can happen in a shower, boiling water on a stove, or by using a washing
machine. Most public water supplies don't present a radon risk, this is because
the water is aerated at the treatment site and the gas escapes into the
atmosphere. Most water that contains hazardous amounts of radon comes from
wells. Wells should be tested for radon if the building that they are supplying
contains hazardous amounts in the air. The testing procedures for water are
different from those used on air.(16)

Water containing radon can usually be treated. The most effective
treatment is to remove radon from the water before it enters the home, this is
called point of entry treatment. Water can also be treated at the tap, this is
known as point of use treatment. However this treatment is much less effective
at removing the risk.(17)

Radon Entry

Radon travels through the ground and into the air, allowing the gas to
easily enter buildings and homes. There are many ways that the gas can enter a
building. Cracks in concrete slabs allow the gas to enter through the floor.
The gas also enters through pores and cracks that are found in concrete
foundations. Faulty wall to floor joints also allow entry. Exposed soil
creates more radon as uranium decays within the soil. A weeping drain tile that
is drained to an open sump will cause radon to enter the home more easily.
Loose pipe fittings will allow enough of an opening to let radon gas enter.
Open tops of block walls let the gas move from the foundation and release in an
open area. Also certain building materials, such as rock used in interior
construction of fireplaces, will release the gas. Domestic use of well water
allows the gas to enter