Fact Sheet 4 October 1992

Southeast Rockford Groundwater Contamination
Rockford, Illinois
Winnebago County

In the summer and fall of 1991, the Illinois Environmental Protection Agency (Illinois EPA) conducted Phase I of an environmental investigation as part of the Southeast Rockford Groundwater Contamination project. The purposes of this investigation included:

1. Preliminary identification of the source or sources of solvents found in southeast Rockford private wells
2. Evaluation of the depth and horizontal extent of the solvent contamination within the present study area boundaries

These solvents are in a class of chemicals called volatile organic compounds (VOCs).

Areas of contamination have not yet been fully defined. The boundaries for the Phase I study were the Rock River on the west, Sandy Hollow Road on the south, Harrison Avenue on the north, and approximately 1.25 miles east of Alpine Road. These boundaries are study area boundaries only and may change as the investigation progresses. Not all private wells in the study area are contaminated.

Based on Illinois EPA, Illinois Department of Public Health (IDPH) and U.S. Environmental Protection Agency (U.S. EPA) sampling, the U.S. EPA Emergency Response section connected over 550 properties to the Rockford public water supply in 1990 and 1991. Wells on these properties had levels of contamination which violated (or potentially could violate) the U.S.EPA public water supply standards. The standards are set to protect people who may drink the water over an average lifetime of 70 years.

• Installation and sampling of 33 monitoring wells and sampling of an additional 35 Illinois State Water Survey wells and privately owned monitoring wells for 24 metals, 19 pesticides and 24 semivolatile and 17 VOCs.
• A soil gas survey of 225 samples in six areas for three VOCs found in the groundwater. The six areas are only a small portion of the entire study area.

The soil gas survey was conducted by driving a hollow tube into the ground to a depth of up to five feet and withdrawing gas (air) from the ground. The gas was analyzed on site for three VOCs which may have vaporized from the groundwater into the air pockets above the groundwater.

Monitoring Well Sample Results (Total VOC 1991)

• VOCs are the prime contaminants of concern.
• Several monitoring wells east of 20th Street showed high concentrations of volatile organic compounds.
• Results indicated several possible sources of contamination. In the eastern area, for example, there may be a plume of contamination originating in the northeastern part and another in the south central part. In addition several southern monitoring wells differed in primary contaminants.
• Water appears to be flowing in a generally westward direction with a significant north/northwest component in the area of Balsam Lane.
• The depth of contamination varies. For example, in the area of Balsam Lane and to the northeast of the study area, contamination is confined to the upper sand and gravel aquifer (water holding geological formation). In the central part of the study area, contamination has penetrated the lower bedrock aquifer.
• The soil gas survey showed only two areas with concentrations high enough to indicate possible soil contamination. One is north of Alton on Marshall Street, and the other is on Kung Street south of Harrison.

Technical Assistance Grants

Citizen groups desiring technical assistance in interpreting data from this investigation may be eligible for a Technical Assistance Grant (TAG). Municipalities, other governmental agencies, political subdivisions, potentially responsible parties, academic institutions and headquarters of public interest groups are not eligible to receive TAGS. However, members of these groups may belong to a community organization requesting a TAG.

The next steps are to gather more information to positively identify contamination sources or to eliminate areas as possible sources. Since groundwater contamination is not easily identifiable at the surface, several phases of investigation may be needed to positively identify all sources.

In Phase II, beginning this fall and continuing into 1993, Illinois EPA contractors will sample soil, conduct additional soil gas surveys and install and sample additional monitoring wells. Based on Illinois EPA information of past industrial practices of industries located north of Harrison and information submitted by some of these industries, the study area has been expended northward to Broadway.

In addition, the Illinois EPA contractors will sample private wells on the edge of the contamination plume to see if contamination has spread. If additional private drinking water wells are found to have levels of contamination that violate the U.S. EPA public water supply standards, the IEPA and U.S. EPA will offer the homeowners a connection to the Rockford public water supply.

After the sources of groundwater contamination have been identified, the Illinois EPA will prepare a study of possible remedies for the contamination. One remedy will be designated as the Illinois EPA and U.S. EPA preferred remedy. All proposed remedies will be submitted to the public for comment before a final remedy is chosen.

Repositories and Administrative Record

More information on the Southeast Rockford Groundwater Contamination may be found in project repositories located at the Rockford Public Library and the Ken-Rock Community Center.

Contact

For more information, please contact the Illinois EPA Office of Community Relations. Additional documents not available on this webpage may be obtained through a Freedom of Information Act request or through IEPA Document Explorer.