Southeast Rockford Groundwater Contamination Superfund Project: Source Area 4 Feasibility Study and Proposed Plan

              Source Area 4
Feasibility Study and Proposed Plan
Southeast Rockford Groundwater Contamination Superfund
Project
June 2001
Rockford, Illinois
What is Source Area 4? Source Area 4 is an
industrial/commercial area in Southeast Rockford shown
on the map below. When the project began, the sources
of groundwater contamination in southeast Rockford
were unknown. In the Phase I project investigation, the
Illinois Environmental Protection Agency (Illinois EPA)
identified 14 study areas as possible sources of
contamination. After several years of study, the Illinois
EPA identified four of these study areas (Areas 4, 7,
9/10 and 11) as the major sources of groundwater
contamination. These study areas, therefore, were
renamed Source Areas 4, 7, 9/10 and 11.
What is the main contaminant at Source Area 4? The main contaminant at Area 4 is 1,1,1-
trichloroethane (TCA) which is an industrial solvent used for such things as degreasing machinery. TCA
is a volatile organic compound (VOC). "Volatile" means it vaporizes (evaporates) easily. "Organic"
means it contains carbon. Tests show free product (solvents undissolved in water) floating on the water
table about 25 feet below ground surface. free product is sometimes call non-aqueous phase liquid
(NAPL). The "Remedial Investigation" fact sheet has more information about Area 4 contamination.
What is the Source Area 4 proposed plan? For each source area, including Area 4, the Illinois EPA
and U.S. Environmental Protection Agency (U.S.EPA) propose one remedy for the contaminated soil and
a second remedy for the leachate. The Illinois EPA and the U.S.EPA studied four alternatives for the soil
remedy in Source Area 4 (Table 1). Of these soil alternatives, the agencies propose excavation and low
temperature thermal desorption (LTTD) (Alternative SCS-4D). The agencies studied five alternatives for
Area 4 leachate (Table 2) and propose leachate containment / collection and treatment (Alternative
SCL-4B).
What is leachate? "Leachate" is source material that has migrated, or could potentially migrate from a
source area into groundwater in the vicinity of the four primary source areas. For purposes of the
Italicized words are discussed in the "Terms" section at the end of the page.
Purpose of This Fact Sheet
This fact sheet describes the feasibility study
(alternative remedies) and the proposed plan for Source
Area 4 of the Southeast Rockford Groundwater
Contamination Superfund project. Fact sheets describing
the alternatives and proposed plans for the other three
major source areas are available from the Illinois EPA
staff and other sources listed at the end of this fact
sheet. A groundwater remedy, focusing on all the
project area groundwater predicted to be affected by
contamination in the next 65 years, was chosen in 1995.
The groundwater remedy is described below.
Source Area 4 Feasibility Study and Proposed Plan - Southeast Rockford Groundwater C... Page 1 of 8
http://www.epa.state.il.us/community-relations/fact-sheets/southeast-rockford/southeast-ro... 5/25/2012