A common environmental concern with homes on Martha's Vineyard is Radon.
What the heck is Radon?
It’s a radioactive gas. It’s colorless, odorless and undetectable by most humans.
So why do I have to worry about it?
Over a period of years exposure to Radon gas can have a
significant and detrimental effect on your health. It
is the second leading cause of lung cancer in the United
States - are you getting that?
Where does it come from?
Radon is a constantly emiting gas that comes from
the natural decay of uranium in the soil. Radon gas seeps
through any access point in a basement or foundation. It
finds its way through cracks, nooks, crannies, poorly sealed
pipes, sump pump pits, drainage basins or any other loose
point primarily in the foundation or at soil line.
Once in the home, the gas can collect in low-lying, closed
areas like basements where it builds up over time to dangerous
Radon may also enter a home through the water supply,
although this problem primarily exists with private wells.
If a Radon test in your home discovers Radon in the air,
and your domestic water comes from a well, it is advisable
to conduct a Radon water test. It takes about 10,000 pCi/L
of Radon in water to raise the Radon level in the air inside
the house by 1 pCi/L. The preferred method for removing
Radon from water is point-of-entry treatment which is aeration
at the water supply. Here is some information from the EPA
on the Proposed
Radon in Drinking Water Rule.
What is a dangerous level?
The Environmental Protection Agency (EPA) of the US Government
has set a threshold of 4 Pico curies/liter (4pCi/L) as the
safe level. Any reading above that is considered to
be actionable. However, I start to get concerned for my
buyer clients when I see a reading above 2 Pico curies/liter.
The World Health Organization's International Radon Project
recommends an action level of 2.7 pCi/L. A reading of 10-12
Pico curies/liter is "equivalent to a pack of cigarettes
a day", according to the EPA guidelines. However, the
debate as to what is and is not dangerous continues with
the UK action level at 10pCi/l and Canada at 15pCi/L.
How widespread is the problem?
Radon has been found in homes throughout all 50 states.
Certain areas are more susceptible than others (Click
here to follow link to Map of Dukes County Radon Zones),
but no location is risk-free. All homes on Martha's
Vineyard have some Radon present and in some isolated pockets
the level is quite high. Up until recently the
higher Radon incidence has been up-Island in areas like
Chilmark, but now we are finding Radon in all areas of the
Island from Edgartown to Tisbury, West Tisbury and beyond.
Concentrations of Radon-causing materials in the soil can
be either natural or man-made. Homes built near glacial
rock formations or shale formations may be at a higher risk.
The only way to tell for sure is to have a home tested.
What do I do if I want to have my home tested?
There are two forms for Radon testing: active and passive.
The instrumentation to perform active testing is usually
expensive and generally requires the services of a structural
inspector or Radon mitigation specialist. Active devises
constantly measure the levels of radon in a portion of the
home and display those results. Passive testing can
be performed by a do-it-yourselfer and the kits are available
at outlets like Ace Hardware or Home Depot. Passive
devices collect samples over a period of time and then are
taken away and analyzed. Either method can help you determine
your level of risk. The government EPA web site provides
information on finding appropriate resources and testing
devices in their Consumer's
Guide to Radon Reduction - How To Fix Your Home.
What do I do if test results show a high level
of Radon gas in my home?
Testing standards are being revised as research continues;
however, if the Radon gas level is too high, a Radon reduction
system should definitely be installed in order to mitigate
the gases. The installation should be done by a professional
to insure that the Radon is effectively mitigated. According
to the EPA, typical Radon mitigation systems can cost between
$800 and $2,500, but on Martha's Vineyard those prices can
be higher. I have a llist of Radon Mitigation companies
that work on the Vineyard on my Martha's
Vineyard Island Service Provider page.
It doesn't matter if you're buying new construction or
an older home, Radon can be a significant issue. Buyers
of Martha's Vineyard homes should be aware of the Radon
risk in the town where they are buying and decide whether
a Radon test is desirable. When in doubt, the EPA
always recommends testing. If seller has had a test
done already, make sure the test results are recent or that
the home has not been significantly renovated since the
test was performed. If in doubt, get a new test done.
It is commonly believed as a rule of thumb that whatever
the Radon level is at the basement level, the Radon level
on the floor above will be about one half of that. Knowlege
and common sense should guide you to make the right decision.
If the reading in the basement is ~2.0pCL/i and you are
never going to finish the basement for use as living space
then you may not need to mitigate. If the Radon level is
higher and the basement is going to be a family room where
a lot of time is spent it might be wise to mitigate.
Normally, mitigation includes running a stack up through
a chase in an interior wall or along the outside wall of
the house with a constantly operating fan in series. I have
had that technique modified so that the stack and fan are
at least 20 feet away from the house and concealed in a
thicket of tall grasses. I strongly recommend when purchasing
a new home in an area where Radon has been found, testing
for Radon preceeds a complete Structural Inspection. For
more information you can consult the EPA