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U.S. EPA REGION 5
WINNEBAGO COUNTY
WINNEBAGO COUNTY

Congressional District # 16

EVERGREEN MANOR GROUND WATER CONTAMINATION

EPA ID# ILD984836734
Last Updated: November, 2014

Site Description

The Evergreen Manor site is a narrow, two-mile long area of low-level groundwater contamination in Winnebago County, Illinois, just north of Roscoe, Illinois.  The primary contaminants found in groundwater at the site are the volatile organic compounds (VOCs) trichloroethylene (TCE) and tetrachloroethylene (PCE).  The contamination was discovered in 1990 when a mortgage company required homeowners to sample their well, and found elevated levels of VOCs.  Between 1990 and 1994 the Illinois Department of Public Health and the Illinois Environmental Protection Agency (IEPA) sampled 267 residential wells, 203 of which had contaminated water, with 108 homes having contamination above drinking water standards.  Between 1993 and 1995 IEPA sampled more residential wells and installed 24 monitoring wells.  The investigations linked the groundwater contamination to industrial sources located near the intersection of Route 251 and Rockton Road, and indicated that the contamination extended southwest from the industrial area, migrating under a mile of open farmland and about 300 homes in the Evergreen Manor subdivision before discharging to the Rock River.

Site Responsibility

This site is being addressed through federal, state, and potentially responsible party (PRP) actions.

Threats and Contaminants

The primary contaminants found in groundwater at the site are trichloroethene (TCE) and tetrachloroethene (PCE), but low levels of other VOCs were also detected. The U.S Environmental Protection Agency (EPA) did not detect any VOCs in the surface water samples that it collected from the Rock River, and surface water does not pose any current risks to human health or the environment.  Low levels of some VOCs were detected in sediment samples collected from the Rock River.  Nevertheless, EPA does not consider the chemicals found in these sediments a risk to human health or the environment.

Cleanup Progress

EPA initiated a non-time critical removal action (NTCRA) that connected 281 residences with contaminated wells to the North Park public water supply in March 1999. EPA completed the public water hookup between 1999 and 2000.

A Record of Decision (ROD) was issued in September 2003 to address residual groundwater contamination at the site. The selected remedy called for local groundwater use controls, Monitored Natural Attenuation, in-home vapor intrusion monitoring, and the development of contingency actions if groundwater or vapor monitoring warranted their implementation. The PRPs conducted the Remedial Design (RD) under an AOC separate from the Remedial Action (RA) in order to establish whether vapor intrusion was a valid concern at the site. In a 2006 memorandum EPA stipulated that it would not require vapor intrusion monitoring if a subsurface investigation demonstrated to EPA's satisfaction that there is an incomplete vapor intrusion pathway.

This investigation re-sampled 24 existing monitoring wells and completed three new vertical aquifer profiles along the center of the contaminated groundwater plume. A report was submitted to EPA on February 13, 2006, concluding that a definable groundwater contamination plume no longer exists, and that the vapor intrusion pathway is incomplete. EPA concurred with these findings on May 24, 2006, and did not require the PRPs to develop a vapor intrusion monitoring program.

The PRPs entered a Consent Decree for Remedial Action (RA) on February 26, 2009, which required groundwater monitoring to ensure that contaminant concentrations remain below remedial standards. The PRPs began their groundwater monitoring program on May 22, 2009, and the last quarterly groundwater monitoring report, submitted December 2011, showed there is no contamination remaining on-site that exceeds remedial standards.

A Final Close-Out Report (FCOR) was completed in September 2012. The FCOR concluded that the implemented remedy achieves the degree of cleanup or protection specified in the ROD for all pathways of exposure. All selected remedial and removal actions, remedial action objectives, and associated cleanup goals are consistent with agency policy and guidance, and no further Superfund response is needed to protect human health and the environment.

Success Story

The last Five-Year Review for Evergreen Manor was completed in 2008.  The report concluded that the remedy is currently protective of human health and the environment because contaminant concentrations are below levels that would preclude Unlimited Use or Unrestricted Exposure (UU/UE), and residences originally affected by the plume have been connected to the public water supply.  Because all monitoring points that still have detectable groundwater contamination are below remedial standards, the remedy is essentially complete.  The BIOSCREEN model employed by U.S. EPA in developing the ROD predicted that under appropriate conditions the contaminant levels could be below remedial standards in as little as 1.5 to 3 years, so these observations were not unanticipated.

A Final Close-Out Report (FCOR) was completed in September 2012. The FCOR concluded that the implemented remedy achieves the degree of cleanup or protection specified in the ROD for all pathways of exposure. All selected remedial and removal actions, remedial action objectives, and associated cleanup goals are consistent with agency policy and guidance. No further Superfund response is needed to protect human health and the environment.

Contacts

Remedial Project Manager, U.S. EPA
william ryan (ryan.williamj@epa.gov)
(312) 353-4374

Community Involvement Coordinator, U.S. EPA
janet pope
(312) 353-0628

Aliases

EVERGREEN MANOR GW CONTAMINATION PLUME
EVERGREEN MANOR GROUNDWATER CONTAMINATIO

 

Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.

 


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