Congressional District # 16
SOUTHEAST ROCKFORD GROUND WATER CONTAMINATIONEPA ID# ILD981000417
Last Updated: July, 2015
The Southeast Rockford Groundwater (SE Rockford) site comprises a three-mile long and two-and-one-half-mile wide area of southeastern Rockford, Illinois. Groundwater investigations conducted by the state of Illinois indicated that residential and municipal wells in this area are impacted by chlorinated solvent contamination. EPA has broken the site into three portions or operable units (OU): OU1 is the drinking water operable unit; OU2 is the groundwater operable unit; and OU3 is the contaminant source control operable unit. OU3 is further subdivided into four major groundwater contaminant source areas that are called Source Areas 4, 7, 9/10, and 11.
Land use within the site area is mainly residential with industrial/commercial developments. The population within one mile of the site is about 52,000.
EPA placed the SE Rockford site on the National Priorities List on June 24, 1998.
The SE Rockford site is being addressed through a combination of state, federal, and potentially responsible party (PRP) actions.
Illinois EPA is the primary technical lead for all of the OUs. However, (U.S.) EPA is the lead enforcement agency and is responsible for negotiating enforcement agreements (e.g. consent decrees (CD)) for Remedial Design/Remedial Action (RD/RA) with the PRPs. Because U.S. EPA signed a CD with Hamilton Sundstrand, the PRP for a portion of Source Area 9/10, it (U.S. EPA) is the primary technical lead for that portion of the site.
Threats and Contaminants
Soil and groundwater at the SE Rockford site are contaminated with chlorinated solvents. Trichloroethene (TCE) (up to 428 ppb), tetrachloroethene (PCE) (up to 545 ppb), 1,1,1-trichloroethane (up to 991 ppb), cis-1,2-dichloroethene (1,233 ppb), and vinyl chloride (up to 114 ppb) have been found in residential groundwater wells. High levels of similar compounds have also been identified at the four Source Area locations. In contrast, the federal Safe Drinking Water Act maximum contaminant level (MCL) for TCE is 5 ppb and for vinyl chloride is 2 ppb.
Ingestion of contaminated groundwater could lead to adverse human health effects.
Cleanup ProgressEPA conducted the first response action at the SE Rockford site in 1991 as a time-critical removal action at OU1. EPA provided service connections to the municipal water supply for 283 residents and installed granular activated carbon treatment on Rockford Municipal Well #35. Illinois EPA and EPA connected an additional 264 homes to municipal water service in 1992.
In September 1995, EPA established long-term cleanup goals for the contaminated aquifer and selected monitored natural attenuation as the cleanup approach. This decision was made with the assumption that major sources of contamination at the site would be addressed under a subsequent action. This decision also called for connection to the municipal water system of homes and businesses whose water wells either recently exceeded health standards or were predicted to exceed them within the next 70 years.
The city of Rockford began implementation of the final groundwater remedy in early 1998 under an enforcement action with Illinois EPA and EPA. Installation of over 9,200 feet of ductile iron water mains and hookup of an additional 262 homes and businesses to water service connections was accomplished by June 1999. Nine additional groundwater monitoring wells were installed to supplement the existing monitoring network. A groundwater monitoring program was also established for OU2. Since 1999, biannual groundwater sampling results have been compiled by Rockford and have been reported to EPA and Illinois EPA. Such monitoring is to continue until cleanup goals are attained.
A separate enforcement action also recovered EPA's and Illinois EPA's past costs with contributions from PRPs. This recovered money is being used to address the largest of four contaminated soil areas, Source Area 7. All four Source Areas continue to pose a potential threat of further contaminant release.
Illinois EPA completed a remedial investigation to evaluate the nature and extent of site contaminants and a feasibility study to evaluate site cleanup options for the four major sources of groundwater contamination (OU3). In June 2002, a Record of Decision (ROD) was signed to address these source areas. Source control techniques included soil vapor extraction, low temperature thermal desorption, and soil excavation. Due to unique source characteristics, some surface/near surface soil work has and will be supplemented with source-specific groundwater management zones (GMZs) and the use of air sparging/soil vapor extraction (AS/SVE) or limited groundwater pump-and-treat steps.
In October 2010, Illinois EPA completed a groundwater treatment system for Source Area 4. That system is currently operating. Some soil excavation was also performed in Area 4, but additional contaminated soil remains in an area that is partially below an operating commercial business. Illinois EPA developed a strategy for remedial actions to address the remaining contaminated soil at Source Area 4 in an Explanation of Significant Differences (ESD) for soil clean-up on July 27, 2012. The ESD calls for the use of electrical resistance heating (ERH) as a tool to remove the volatile site contaminants from the soil. The state plans to begin the ERH remedial action for Source Area 4 soil in 2015.
Illinois EPA completed pre-remedial design sampling at Source Area 7 and excavation of contaminated soil was completed in 2011. Initial Remedial Design for Area 7 was completed in February 2013. Illinois EPA installed extraction wells for the Source Area 7 groundwater remedy in March 2013. Construction of the Source Area 7 water treatment plant for groundwater cleanup is planned to begin in 2015, with completion of the treatment plant construction planned for late 2015 or early 2016.
EPA finalized negotiations in early 2003 with Hamilton Sundstrand, a PRP for Source Area 9/10, and, as a result a CD for RA at Source Area 9/10 was signed on September 2, 2008. After EPA and Illinois EPA approved the RA work plan, remedial actions in Source Area 9/10 began on November 24, 2008 with the installation of two phases of air sparging and soil vapor extraction. An ESD for soil excavation in the former Outside Storage Area (OSA) was signed in February 2009. Soil excavation at the OSA was conducted with off-site disposal, and residual soil contamination at the edges of the excavated area was treated using soil mixing and a chemical oxidizer. Currently, the air sparge/soil vapor extraction system is operating in pulse (on/off/on) mode.
After completion of pre-design sampling, monitoring wells were installed in Area 11 as a part of the Remedial Design for that remedy. After a period of two years of observation, in 2013, Illinois EPA initiated a monitored natural attenuation remedy for this part of the site.
EPA completed a Five-Year Review (FYR) at the site in June 2013. The FYR report recommended that, due to the levels of VOCs in monitoring wells, a deep soil gas sampling event be conducted in residential areas to determine whether there is a risk for vapor intrusion in homes. Additionally, it was recommended that a pore water study of the Rock River was needed to determine whether there are any ecological impacts from the discharage of VOCs into the river. EPA completed the Rock River study during July 2014. Deep soil gas sampling was conducted in August 2014 and October 2014. A report on the results of the pore water was approved by EPA in May 2015 and placed in the public record for the site. A draft soil vapor evaluation was submitted to EPA and Illinois EPA and is currently being finalized. Based on the results of the deep soil gas evaluation, follow-up shallow soil gas sampling will be conducted during August 2015 and then again during the following winter. The results will be placed in the public record for the site.
Success StoryRA work is complete for OUs 1 and 2. RD and RA work have begun for all of the Source Areas of OU3 either by Illinois EPA or by the PRPs. That work will continue into 2015 and beyond.
At appropriate points in the cleanup processes, Illinois EPA and EPA have conducted public meetings. The most recent public meeting was held by Illinois EPA and EPA in July 2013 to present the results of the recently completed FYR of the site.
Property ReuseAt the conclusion of RD/RA, properties will continue in their existing use as residential or industrial/commercial properties.
ContactsRemedial Project Manager, U.S. EPA
timothy drexler (email@example.com)
Community Involvement Coordinator, U.S. EPA
AliasesSOUTHEAST ROCKFORD GD WTR CONTAMINATION
SOUTHEAST ROCKFORD DRY WELL
SE ROCKFORD GROUNDWATER CONT