Southeast Rockford Groundwater Contamination Superfund Project: Source Area 4 Results of Indoor Air Samples

              Source Area 4
Results of Indoor Air Samples
Southeast Rockford Groundwater Contamination Superfund
Project
July 2004
Rockford, Illinois
Results of Indoor Air Samples
In August 2003, the Illinois Environmental Protection Agency
collected indoor air samples from four homes near Source Area 4
of the Southeast Rockford Groundwater Contamination Superfund
Project. (See the map below.) The Illinois EPA collected and
analyzed these samples to make sure that underground vapors
from the source area are not moving into the basements of
nearby homes.
How does Illinois Department of Public Health evaluate
these sample results? In a letter to owners and renters of all
sampled homes, with the exception of a home with an unsealed
well pit, the Illinois Department of Public Health (IDPH)) stated
that the levels of VOCs (volatile organic compounds)1 detected in
the Area 4 indoor air samples would not be expected to cause
short-term or long-term health effects and would pose no
apparent increased risk of cancer.
In the letter to the owner and resident of the home with the well
pit, IDPH stated, “The levels of VOCs detected in your basement
would not be expected to cause short-term health effects.
Exposure to the level of TCE (one chemical) detected in your
basement over a period of many years may present a low
increased cancer risk. Based on the results of your sample, we
recommend that the well pit in this basement be sealed in such a
way to reduce VOCs entering the home.” Since then, the owner of
the house has sealed the well pit.
In general, what were the sample results from the four
Area 4 homes and how did results compare to the
background sample? It is difficult to evaluate indoor air
samples, since most of these chemicals are found in common
household products such as solvents, paints, cosmetics and glues.
They are also commonly found in urban outdoor air. With those uncertainties in mind, a summary of
Illinois EPA findings follows:
􀁺􇩁 All houses, including the background house2 used for comparison, slightly exceeded the most
conservative U.S. EPA indoor air screening values for three to five chemicals. Screening values are
not action values but values that indicate the Illinois EPA should take a closer look. They are
conservative in that they assume that residents live in the sampled area (the basement) 350 days
a year, 24 hours per day for thirty years. It is not surprising that chemicals were detected in the
background comparison house because of the presence of these chemicals in household products.
􀁺􇩔 The house that had the overall highest concentrations had an improperly sealed well pit in the
basement, which could have provided a pathway for underground vapors to seep from the outside
into the basement. Since the sampling date, the Illinois EPA has been notified that the well has
been sealed, and the agency is waiting for certification that the seal meets state regulations.
What is Source Area 4? Illinois
EPA investigations beginning in
1991 identified Area 4 as one of
four major sources of private
well contamination in southeast
Rockford. The investigations
showed that sources of
contamination in Area 4 appear
to be spillage/disposal and an
underground storage tank.
Contaminants include waste oils
and the industrial solvents 1,1,1-
trichloroethane and
trichloroethylene. Information on
the other three source areas is
available from sources listed on
the last page.
Is my water safe to drink?
Area residents who are using
Rockford Public Water Supply do
not have to worry about the
safety of their drinking water.
The Rockford Water Supply is
regularly tested for possible
contaminants. Water that
violates U.S. Environmental
Protection Agency (U.S. EPA)
drinking water standards is not
distributed to the public.
Source Area 4 Results of Indoor Air Samples - Southeast Rockford Groundwater Contami... Page 1 of 4
http://www.epa.state.il.us/community-relations/fact-sheets/southeast-rockford/southeast-ro... 5/25/2012