Fact Sheet 13b
Source Area 7 Results of Indoor Air Samples
Southeast Rockford Groundwater Contamination Superfund Project
What is Area 7?
Illinois EPA investigations beginning in 1991 identified Area 7 as one of four major sources of private well contamination in southeast Rockford. Source Area 7 is a former unregulated disposal area, evidently used for both household and industrial waste. The area, located north of Balsam Lane, now contains a field, wooded areas and Ekberg Park. The contamination is located between 4 feet to at least 29 feet below ground surface. Information on the other three source areas is available from sources listed on the last page.
Is Pine Manor Subdivision built on an old disposal area?
No. Old aerial photographs and Illinois EPA test results confirm that the western boundary of the old disposal area is located several hundred feet east of the Pine Manor Subdivision.
Is it safe for my children to play in the park?
Yes. Illinois EPA samples showed that the major contamination is several feet below the ground surface. Illinois EPA evaluation of surface samples showed no contamination at levels of concern for people using the park.
Is my water safe to drink?
Area residents who are using Rockford Public Water Supply do not have to worry about the safety of their drinking water. The Rockford Water Supply is regularly tested for possible contaminants. Water that violates (U.S. EPA) drinking water standards is not distributed to the public.
Results of Indoor Air Samples
In August 2003, the Illinois Environmental Protection Agency (Illinois EPA) collected indoor air samples from five homes near Source Area 7. (See the map on page 2) This sampling was conducted as part of the Southeast Rockford Groundwater Contamination Superfund Project. The Illinois EPA collected and analyzed these samples to make sure that underground vapors from Source Area 7 are not moving into the basements of nearby homes.
How does Illinois Department of Public Health evaluate these sample results?
The Illinois Department of Public Health (IDPH) stated that the levels of VOCs (volatile organic compounds) 1 detected in the indoor air samples from the five Area 7 homes would not be expected to cause short-term or long-term health effects and would pose no apparent increased risk of cancer.
In general, what were the sample results from the five Area 7 homes and how did results compare to the background sample?
It is difficult to evaluate indoor air samples, since most of these chemicals are found in common household products such as solvents, paints, cosmetics and glues. They are also commonly found in urban outdoor air. With those uncertainties in mind, a summary of Illinois EPA findings follows:
- All houses, including the background house 2 used for comparison, slightly exceeded the most conservative U.S. Environmental Protection Agency (U.S. EPA) indoor air screening values for one or more chemicals. Screening values are not action levels but values that cause the Illinois EPA to take a closer look. They are conservative in that they assume that residents live in the sampled area (the basement) 350 days a year, 24 hours per day for thirty years. It is not surprising that chemicals were detected in the background comparison house because of the presence of these chemicals in household products.
- All houses, including the background house, slightly exceeded U.S. EPA guidelines for benzene, a chemical associated with gasoline. Since benzene is not found in the underground vapors, its source must be gasoline or other products stored in the houses or fumes in the outside air from automobile exhaust.
Area 7 Remedy
What is the Area 7 remedy?
The remedy for Source Area 7 is divided into two parts. One is the remedy for soil and the other is the remedy for leachate. In June 2002, after considering public comment, the Illinois EPA and the U.S. EPA chose multi-phase extraction and leachate containment as the remedies for Area 7. The map below is a schematic of the remedies. The following page describes the remedies in more detail.
What is the source of funding for the Area 7 remedy?
In a January 13, 1999 amended consent decree, the City of Rockford, with contributions from other parties, agreed to pay a $5 million cash-out for Area 7. The U.S. and Illinois governments gave covenants not to sue for further costs in Area 7 to parties that contributed to the costs the City of Rockford incurred by this settlement. The money from this settlement will be used to design and construct the remedy for Area 7.
1Volatile organic compounds are the chemicals of concern in Area 7. The chemicals are called “volatile” because they vaporize (evaporate) readily and organic because they contain carbon. The VOCs found in Area 7 are primarily industrial solvents.
2Background samples are samples collected in areas thought to be unaffected by contamination. They are collected for comparison to samples taken closer to the contamination.
In July 2004, the Illinois EPA will be conducting predesign investigations to complete information about the extent of contamination north of the park. The design for the remedy is planned for completion this year. Construction of the remedy will begin in 2005 if the Illinois EPA obtains access to all of the property that is needed for the remedy.
What is the predesign investigation?
The predesign investigation is planned to collect data to fill gaps in the agency’s information about VOCs in soil gas (air beneath ground surface), soil and groundwater.
Soil gas. The Illinois EPA contractor will collect up to 43 soil samples north of the playground and south of the railroad tracks. These samples will be collected for two reasons: (1) Previous results from some of the northern-most soil gas samples showed VOCs. July sample locations will be placed to better understand how far north VOCs in soil gas have moved. (2) July sample results will also be compared to previous sample results to see if concentrations have changed over time.
Groundwater. Groundwater screening samples will be collected in the area south of Balsam in the area proposed for the leachate extraction wells. These extraction wells are part of the remedy for Area 7. A screening sample is collected by pushing a probe beneath the ground surface and collecting a sample directly from the groundwater. In addition, two to three new monitoring wells will be installed in the same area to monitor VOCs in the shallow groundwater.
Soil. A maximum of 30 soil samples will be collected at various depths. The sample locations will be selected to confirm detections of VOCs in the soil gas.
Source Area 7 Remedy
Institutional controls. Institutional controls will be placed on the property, restricting use of the property until remediation goals are met. Institutional controls could include zoning restrictions, city ordinances, easements, covenants, consent decrees or notices on deeds and state registries.
Soil vapor extraction. Since the contaminants are VOCs and VOCs vaporize readily, a system will be installed to remove the underground VOC vapors. These vapors will be removed by 16 vacuum extraction wells constructed in the contaminated areas. Removing the vapors will gradually reduce the amount of contamination underground.
Air sparging injection well system. Air will be injected into the soil and leachate, increasing the amounts of VOCs that vaporize into the air pockets in the soil above the water table. Injecting air into the soil and leachate is called air sparging.
Catalytic oxidation. The vapor from the soil vapor extraction system will be directed to a catalytic oxidation unit. This unit will break the VOCs into harmless compounds such as water vapor and carbon dioxide plus hydrochloric acid. A scrubber will treat hydrochloric acid to form water and salts. The treated water will be discharged to a nearby drainage ditch.
Air monitoring. Air emissions from the catalytic oxidation unit will be monitored to ensure all air quality standards are met.
Leachate is contamination that has moved or could potentially move into the groundwater. For purposes of this fact sheet, leachate includes the groundwater at Area 7 that must be contained or controlled to protect human health and the environment.
Institutional controls. A restriction will be placed on the property restricting use of the property until remediation goals are met.
Multi-phase extraction. A vacuum will be applied to a series of extraction wells. The vacuum will collect soil vapors, free-product 1 and groundwater. (Vapors, free product and water are different “phases”—thus, the term multi-phase extraction).
Leachate containment. Leachate will be collected through eight containment wells constructed at the of Source Area 7 boundary to prevent the leachate from moving past the groundwater management zone 2 boundary.
Air stripping. Since the contaminants are volatile (they vaporize easily), they can be removed from leachate by exposing the leachate to air and letting the contaminants evaporate. This process is called air stripping.
Catalytic oxidation unit. VOCs collected from the air stripper and from the multi-phase extraction unit will be treated by a catalytic oxidation unit.
Air monitoring. Discharges to the air will be monitored to ensure that they meet all federal and state laws and requirements.
Water monitoring. After the contaminants are removed from the leachate, the remaining water will be discharged to the ditch. The water will be monitored to ensure it meets all federal and state standards and requirements.
1Free product occurs when a contaminant is present in high enough concentrations in groundwater that it does not dissolve in water. If it is lighter than water (like oil), it will float on top of the water. If it is heavier than water, it will sink through the water until it comes to a barrier such as rock or clay.
2A groundwater management zone is the area of contaminated groundwater that will be treated by the Area 7 leachate remedy. See map on page 2. The Area 7 leachate remedy goal will be met when the groundwater meets Class I Groundwater Standards, which are based on federal drinking water standards.
For More Information:
Contacts: For more information about the project including fact sheets on the remedial investigation results, feasibility studies and proposed plans for each of the four major source areas, you may contact the Illinois EPA staff listed below:
Community Relations Coord.
1021 N. Grand Ave. E.
Springfield, Illinois 62794-9276
Phone: (217) 524-2292
1021 N. Grand Ave. E.
Springfield, Illinois 62794-9276
Phone: (815) 223-1714
Repositories: Full reports for the project may be reviewed at the following locations.
Rockford Public Library
3128 S. 11 th Street
Rockford, IL 61109
(Call for hours)
3218 S. 11th Street
Rockford, IL 61109
(Call for hours)
Administrative record file: The administrative record file is located at the Illinois EPA headquarters in Springfield, Illinois. Call 217/782-9878 for an appointment. The administrative record file will also be located on microfiche at the Main Branch of the Rockford Public Library at 215 N. Wyman in Rockford.