U.S. Environmental Protection Agency, Region 3
Delaware, Maryland, Pennsylvania, Virginia, West Virginia and rag District of Columbia
HIDDEN LANE LANDFILL SUPERFUND SITE
COMMUNITY UPDATE
Sterling, ya
EPA Tests Treatment Option
to Address Groundwater
Contamination
In an effort to more efficiently clean up the trichlo-
roethene (TCE) contamination in the groundwater
at the Hidden Lane Landfill site, EPA is conducting
what's called a "treatability study." The results of
the study will tell us if we can effectively treat the
TCE contamination in place.
As part of the study, EPA plans to drill four new
monitoring wells near the western boundary of the
Hidden Lane Landfill. EPA will then inject treat-
ment compounds into the contaminated groundwa-
ter. These compounds are designed to degrade the
TCE. We will be able to measure the success of the
degradation by sampling the monitoring wells.
The study is expected to take one year to complete.
EPA will share the results of the study with the
community including any additional steps that may
be needed in order to treat the TCE contamination.
EPA to Test Indoor Air
Beginning this fall, EPA plans to sample indoor air
at several residential and business properties to en-
sure that they are not being impacted by "vapor in-
trusion."
TCE is classified as a "volatile organic compound"
which means it has the ability to vaporize, or "off-
gas," into the air inside buildings and homes. EPA
calls this vapor intrusion.
EPA will contact a certain number of property own-
ers individually to obtain permission to sample their
indoor air. The process is entirely voluntary, easy,
and done at no cost to the owner.
	November 2014
To evaluate whether indoor air is being impacted
by vapor intrusion, two types of air samples are
taken:
1. Soil Vapor Samples: These samples are called
sub-slab samples because they are taken from
under a building's foundation. Soil vapors will be
collected from beneath the building slab or
basement floor through a small hole, using a sam-
pling probe about size of a quarter. Once installed
the sampling probe is flush with the floor, water-
proof, and can be walked-on, covered over, or
completely ignored until a sample needs to be tak-
en.
Drilling through
slab to install probe
Finishing probe
installation
Finished product
is the size of a
quarter

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2. Indoor Air Samples: These samples are taken
from the lowest point in the building and possibly the
next level up. Air is collected slowly over a 24- hour
period using a Summa Canister (pictured below),
which is about the size of a basketball.
Summa Canister
What Is vapor Intrusion?
Vapor intrusion refers to chemical vapors that can
move up through soil and seep into buildings. It can
occur when chemicals are spilled on the ground,
poured down drains or disposed of improperly. These
chemicals, usually volatile organic compounds
(VOCs), can 'off gas' from contaminated groundwa-
ter or soil. These vapors can enter buildings through
cracks in concrete slabs, basement floors and walls,
and through openings around sump pumps or where
pipes and electrical wires go through the foundation.
This pathway is similar to how radon gas seeps into
buildings.
It is important to note that there are many other
sources of VOCs that can impact the air inside build-
ings. Many common products contain chemicals that
may add to VOCs in the air you breathe. These prod-
ucts include paints, glues, cleaning products, cigarette
smoke, gasoline stored in garages, thinners, etc. When
testing for specific VOCs, like TCE at Hidden Lane,
steps are taken to make sure these other sources are
considered.
For additional information about vapor intrusion, go
to: http://www.epa.gov/oswer/vaporintrusion/
Contact us
Fred MacMillan
EPA Remedial Project Manager
215-814-3201
macmillaii.fred@epa.gov
Larry Johnson
EPA Community Involvement Coordinator
215-814-3239
iolinson.larrv-C@epa. gov
For more information about EPA's work at the
Hidden Lane site, visit:
http://www.epa.gov/reg3hwmd/super/sites/
VAD980829030/index.htm

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