Congressional District # 16
EVERGREEN MANOR GROUND WATER CONTAMINATIONEPA ID# ILD984836734
Last Updated: November, 2011
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 a homeowner 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 ResponsibilityThis site is being addressed through federal, state, and potentially responsible party (PRP) actions.
Threats and ContaminantsThe 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 (U.S. 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, U.S. EPA does not consider the chemicals found in these sediments a risk to human health or the environment.
In March 1999, U.S. EPA initiated a non-time critical removal action (NTCRA) to connected 281 residences with contaminated or endangered wells to the North Park public water supply. In May 1999, three potentially responsible parties (PRPs), Waste Management, Regal-Beloit, and Ecolab signed an Administrative Order on Consent (AOC) to conduct the NTCRA. U.S. EPA completed the public water hookup between 1999 and 2000, and the private wells at the affected homes were permanently sealed according to state code.
In 2000, U.S.EPA began a federally-funded remedial investigation and feasibility study (RI/FS) to evaluate the groundwater contamination at the site and develop cleanup strategies. The RI/FS found that the groundwater contamination is attenuating naturally and projected that natural attenuation should attain cleanup standards by 2015 without additional remedial efforts.
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. U.S. EPA signed an AOC with Ecolab and Waste Management of Illinois on September 29, 2004, to perform a Remedial Design (RD). U.S. EPA allowed the PRPs to conduct 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 U.S. EPA stipulated that it would not require vapor intrusion monitoring if, after an acceptable subsurface investigation is performed in accordance with the OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils, it is demonstrated to EPA's satisfaction that there is an incomplete vapor intrusion pathway.
The RD investigation re-sampled 24 existing monitoring wells and completed three new vertical aquifer profiles along the center of the contaminated groundwater plume. Sample results from the monitoring wells and vertical aquifer profiles indicated no contamination exceeding the remedial standards established in the ROD remained on the site. A RD Report was submitted to U.S. EPA on February 13, 2006, concluding that a definable groundwater contamination plume no longer exists and that the vapor intrusion pathway is incomplete. U.S. EPA concurred with these findings on May 24, 2006, and did not require the respondents to develop a vapor intrusion monitoring program.
Waste Management and Ecolab entered a Consent Decree for Remedial Action (RA) on February 26, 2009, which requires groundwater monitoring to ensure that contaminant concentrations remain below remedial standards. The PRPs began their groundwater monitoring program on May 22, 2009, and as of the latest quarterly groundwater monitoring report, submitted December, 2010, there is no contamination exceeding remedial standards. U.S. EPA expects one last groundwater monitoring report will be submitted in December 2011.
Because the ROD remains in effect, the provisions for the implementation of contingency actions will protect human health and the environment should future monitoring indicate that conditions are deteriorating.
The last Five-Year Review 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. Nevertheless, groundwater monitoring will continue to ensure that contaminant concentrations remain below remedial standards until such time that U.S. EPA determines that the site requires no further action. The next Five-Year Review will be completed in 2013.
ContactsRemedial Project Manager, U.S. EPA
william ryan (firstname.lastname@example.org)
Community Involvement Coordinator, U.S. EPA
AliasesEVERGREEN MANOR GW CONTAMINATION PLUME
EVERGREEN MANOR GROUNDWATER CONTAMINATIO