Southeast Rockford Groundwater Contamination Superfund Project

Summary of Phase II Remedial Investigation Results

Southeast Rockford Groundwater Contamination Superfund Project

February 1995

Rockford, Illinois

Phase II Investigation Results

What is the purpose of the Phase II investigation?

The purpose of Phase II is to define the nature and extent of groundwater contamination and to preliminary identify the source or sources of industrial solvents which contaminated Municipal Well #35 and a number of private wells in southeast Rockford. These industrial solvents are part of a group of chemicals called volatile organic compounds (VOCs).

What are the sources of well contamination in southeast Rockford?

The Phase II investigation identifies four areas that appear to contribute to the VOC contamination in southeast Rockford wells. These areas are outlined on the map as Areas 4, 7, 9/10, and 11 (see map). The unnumbered areas were investigated during Phase II but will not be studied further under the Southeast Rockford Groundwater Contamination Superfund project.

Area 4. Contamination in Area 4 appears to be the result of operations at a metal parts manufacturing facility located on Marshall Street between Harrison and Alton Avenues. In this area, 1,1,1-trichloroethane generally was found in much higher concentrations than other contaminants. Subsurface soil sampling showed the presence of a dark, oily product at the top of the water table indicating the presence of free-product from about 28 to 36 feet below ground surface.

Area 7. The major source of contamination appears to be Area 7- a former unregulated disposal area located on the east end of Balsam Lane. The area is now a park and field. The major contaminants from this area include chlorinated solvents such as 1,1,1-trichloroethane and perchloroethylene as well as non-chlorinated solvents such as toluene and xylene. The northern* extent of Area 7 has not yet been fully defined.

Area 9-10. These two areas appear to be located on the east and west sides of 9th Street about a block north of Harrison Avenue. The main contaminants in these areas are 1,1,1-trichloroethane, trichloroethylene, and perchloroethylene. This area needs further study. Area 11. In Area 11, which is located east of llth Street and north of Harrison Avenue, soil borings showed contaminated soils across a broad area. VOC contamination in Area 11 is dominated by toluene, ethylbenzene, and xylene at very high concentrations. The abundance of these compounds in Area 11 may result from their common use in paints, paint thinners, coatings, and varnishes. This is consistent with the former use of the property by Rockford Varnish. The contaminants in Area 11 usually were not found in southeast Rockford private wells. The very high concentrations of toluene, ethylbenzene, and xylene, 1however, may have masked the presence of chlorinated solvents such as 1,1,1-trichloroethane, so further investigation is needed.

Other areas. The other areas shown on the map may have problems with groundwater contamination, but the contamination does not appear to contribute to the southeast Rockford private well contamination or the contamination of Municipal Well #35.

What is the extent of contamination as defined by the Phase II investigation?

The map also outlines the area of known groundwater contamination. The dotted lines outline the areas which are judged to be contaminated based upon knowledge of groundwater flow direction and other factors. Depth of contamination varies. In some places around Area 7, the contamination is located only in the upper sand and gravel. West of Area 7, contamination penetrates the bedrock to a depth of at least 220 feet.

Is the contamination spreading?

Phase II information indicates that the contamination may spread within the next 70 years. This spring, the IEPA and the USEPA will make a recommendation, for public comment, on methods to prevent risks which might otherwise occur in the future.

This map shows the extent of chlorinated VOCs in groundwater. Non-chlorinated VOCs (such as those found at Area 11) were found less frequently in Phase II and do not appear on this map. View larger map

A Discussion of Possible Health Risks

Is the Rockford Public Water Supply safe?

Yes. Water from the Rockford Public Water Supply is regularly tested for chemicals found in the Superfund area. If water violates USEPA public water supply standards, it is not distributed to the public.

Do any of the private wells remaining in the study area pose a risk to human health?

Phase II investigation results indicate that no additional wells in the study area have become contaminated at levels which would pose a risk from short-term exposure. The IEPA and the USEPA are further evaluating the Phase II data to determine if additional homes should be connected to the public water supply to protect residents from incurring risks from long-term (years of) exposure. This evaluation will be presented to the public for comment this spring. It should be noted, that in 1990 and 1991, the IEPA and USEPA offered owners of approximately 550 homes a public water supply connection. A few owners refused, and the drinking water in their homes still poses a health threat to its users.

Will my costs be reimbursed if I pay for a connection to the Rockford Public Water Supply?

No. This spring, the IEPA and USEPA will present for public comment a draft feasibility study and proposed plan which will contain their recommendations about future public water supply connections. If, after considering public comment, the IEPA and USEPA decide additional homes should be connected to the Rockford Public Water Supply, these homes (with the owners' consent) will be connected using federal and state funds. If homeowners have connected their houses to the public water supply system at their own expense, their costs will not be reimbursed.

Are harmful vapors of VOCs migrating from the groundwater into my basement?

According to present data, no. The IEPA and the Illinois Department of Public Health (IDPH) have tested air in a number of homes in neighborhoods with the greatest groundwater contamination. The VOCs found in the groundwater are also present in common household products such as cleaners, waxes, glues, and paints. To date, it is difficult to determine sources of VOCS, but in no case did the IDPH or the IEPA find VOCs at concentrations which exceeded levels found in the average American urban home.

Work Completed During Phase II

• 44 monitoring wells installed and sampled and an additional 76 previously installed monitoring wells sampled .A total of 165 groundwater samples were collected.
  
  
• 24 private wells sampled
  
  
• 55 subsurface soil borings drilled and 116 subsurface soil samples collected
  
  
• Soil gas survey conducted in five areas
  
  
• Air in the basements of homes sampled
  
  
• Two test pits excavated and sampled

Future Actions

What are the next steps?

The next steps include a feasibility study of alternatives to address contaminated groundwater, completion of the investigations of the source areas, and a feasibility study of additional remedies, if needed, for the source areas. Feasibility studies include an evaluation of a wide range of alternatives, from no action to aggressive action. The approximate schedule planned for these actions is as follows;

Planned Schedule

For Additional Information

Repositories and Administrative Record

Repositories of project information (including information on Area 7) are located at the Rock River Branch of the Rockford Public Library (3134 S. 11th Street) and the Ken?Rock Community Center (3218 S. 11th Street). The administrative record file (a file that contains documents upon which decisions are based) is located on microfiche at the main branch of the Rockford Public Library (215 N. Wyman).

Contacts:

Glossary

Electromagnetic survey.

A method of survey which is used to detect the presence of metal objects beneath ground surface.

Feasibility study.

A study which identifies and evaluates the most appropriate technical approaches for addressing contamination problems at a Superfund site. The alternatives are evaluated using a number of criteria including effectiveness in protecting human health and the environment, community acceptance, and cost.

Groundwater.

Water beneath the ground surface.

Ground penetrating radar.

A method of survey which is used to determine the presence of disturbed areas and changes in the geology beneath ground surface.

Monitoring well.

A well installed at a known depth used to measure groundwater characteristics such as the presence or absence of contamination, the distance to the water table, and the direction and speed of groundwater flow.

Soil borings.

A method of collecting soil samples beneath ground surface. In Area 7 some soil borings reached a depth of 47 feet.

Soil gas survey.

A method of survey in which a probe is driven into the ground, and air beneath the surface is withdrawn and analyzed for volatile organic compounds.

Superfund.

The common name for the federal program established by the Comprehensive Environmental Response Compensation and Liability Act of 1980 as amended in 1986. The Superfund law authorizes USEPA to investigate and clean up the nation's most serious hazardous waste sites. The law also allows the USEPA to delegate some authority to the states.

Test pit.

A test pit is a small hole excavated under highly controlled conditions in order to collect samples and observe material beneath the surface. In areas of disposal by unknown parties, a test pit can provide an opportunity to observe waste and gather information on who may be responsible for disposing of the waste.

Volatile organic compound (VOC).

An organic (carbon-containing) compound that evaporates (volatilizes) readily at room temperature.