Fact Sheet 2

Rantoul, Illinois

Introduction

This is the second of a series of Illinois EPA fact beets to acquaint you with the environmental restoration program at the former Chanute Air Force Base (AFB). These fact sheetscontain information regarding various topics of concern; including site history, site status; and any site-specific issues which need to be addressed in a timely manner. The purpose of this fact sheet is to discuss the remedial investigation (RI) to be conducted on Landfills 1; 2, 3; and 4 in Operable Unit 2 (OU-2) at the former Chanute Air Ford Base (AFB) in Rantoul Illinois, in order to establish if these landfills pose an unacceptable risk to human health and/or the environment.

The U.S. Air Force Installation Restoration Program

The objective of the U.S. Air Force Installation Restoration Program (IRP) is to assess past hazardous waste disposal and spill sites at Air Force installations, and to develop remedial actions consistent with the National Contingency Plan (NCP) for sites that pose a threat to human health and welfare or the environment.

The 1976 Resource Conservation and Recovery Act (RCRA) is one of the primary federal laws governing the disposal of hazardous wastes. This law requires federal agencies to comply with local and state environmental regulations and to provide the U.S. Environmental Protection Agency (USEPA) concerning past disposal practices at federal sites. RCRA also requires state agencies to inventory past hazardous waste disposal sites and to provide information to the USEPA concerning those sites.

The Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or "Superfund") was enacted by Congress in 1980. CERCLA outlines the responsibility for identifying and remediating contaminated sites in the United States. CERCLA identifies the USEPA as the primary policy and enforcement agency regarding contaminated sites.

The 1986 Superfund Amendments and Reauthorization Act (SARA) extends and modifies the requirements of CERCLA with respect to goals for remediation and the steps that lead to the selection of a remedial process. SARA is the primary legislation governing remedial action at past hazardous waste disposal sites.

Executive Order 12580, adopted in 1987, gave various federal agencies, including the Department of Defense (DOD), the responsibility to act as lead agencies for conducting investigations and implementing remediation efforts when they are the sole or co-contributor to contamination on or off their properties.

To ensure compliance with CERCLA, its regulations, and Executive Order 12580, the DOD developed the IRP, under the Defense Environmental Restoration Program, to identify potentially contaminated sites, investigate these sites, and evaluate and select remedial actions for potentially contaminated facilities. The IRP is the DOD's primary mechanism for response actions on Air Force installations affected by the provisions of SARA. Over the years, requirements of the IRP have been developed and modified to ensure that DOD compliance with federal laws and regulations such as RCRA, CERCLA, SARA, and the NCP can be met.

Waste Disposal Activities at Chanute AFB

Limited historical information is available regarding past waste disposal activities at Chanute Air Force Base, particularly during the early years of operation. During 1930s and 1940s, waste generated at the AFB was disposed primarily by placing waste material and refuse in open dumps. Flammable materials such as fuels, solvents, and oils were often disposed by using them for firefighting training activities. In the 1950s and 1960s, waste disposal activities began to shift over to utilization of landfills where waste materials were placed in excavated trenches and covered with soil. Landfills 1, 2, 3, and 4 at the Base were used in chronological and numerical order; that is, the first open dump area utilized for receiving and burning waste (in the 1930s) is now referred to as Landfill 1, and the last open dump area utilized for receiving and burning waste (in the early 1970s) is referred to as Landfill 4. Landfills 1, 2, 3, and 4 are located in the southeast portion of the Base. Each landfill comprises an area of roughly 20 acres and each is filled to a depth of approximately 3 to 12 feet. Since the 1970s, hazardous waste materials (typically solvents and degreasers) have been removed from the Base by licensed waste haulers. Since the waste disposal activities have ceased, the land surface at the four landfills has experienced differential settling, resulting in areas of ponded water during wet periods of the year. The following provides a brief description of the history of each of the four landfills:

• Landfill 1 received the majority of the wastes generated at the Base during the early years of operation of 1941 through 1960. The wastes were routinely burned and were deposited at a depth of 8 to 10 feet. Landfill 1 received garbage, paper, wood, metal, ashes, aircraft parts, unrinsed pesticide containers, construction/demolition debris, and various shop wastes, including solvents.
• Landfill 2 was in operation from the early 1950s through 1967. Landfill 2 received the same types of waste as Landfill 1 and may have been where four drums containing 2,4-dichlorophenoxyacetic acid and/or 2,4,5-trichlorophenoxyacetic acid and 50 one-ounce wax-encased sealed containers of zinc phosphide were disposed. The wastes were occasionally burned and were deposited at a depth of approximately 8 to 10 feet.
• Landfill 3 was in operation from 1967 to 1970 and received garbage, refuse, shop wastes and possibly the four drums of 2,4-dichlorophenoxyacetic acid and/or 2,4,5-trichlorophenoxyacetic acid. The wastes were occasionally burned and deposited at a depth of 6 to 8 feet.
• Landfill 4 was in operation from 1970 to 1974 and received Base garbage, refuse, shop wastes, and construction/demolition debris. Wastes were infrequently burned and deposited at a depth of 8 to 10 feet.

Previous Investigative Activities at Chanute AFB

The first hazardous waste investigation at Chanute AFB under the Installation Restoration Plan was conducted in 1982. This initial investigation (considered Phase I) included interviews with past and present Base employees and facility inspections. By 1983, six sites were discovered through this initial assessment. From 1984 to 1986, confirmation and quantification studies were done at these six sites. An additional site was discovered during this time. From 1987 through 1993, Remedial Investigative (RI) fieldwork at the original seven sites and at four additional sites (including Salt Fork Creek) was done. A new IRP site was discovered in 1990. The objective of this fieldwork was to confirm the presence or absence of contamination at these individual with histories of waste disposal, spills, and leaks. Activities included monitoring well installation, groundwater and hydrologic sampling, and a geophysical survey.

(Note: At this time, several IRP and underground storage tank (UST) sites have been identified at Chanute AFB; in addition to the four landfills, there are two fire training areas, fourteen oil/water separators, one trichloroethylene (solvent) spill, one sludge disposal pit, 66 USTs, and two fuel transfer lines.)

Description of Current Remedial Investigation

The primary purposes of the Landfills RI are to:

• determine the presence or absence of hazardous waste within Landfills 1, 2, 3, and 4; and
• determine the nature and extent of contamination associated with the landfills, in order to establish if these landfills pose unacceptable risk to human health or the environment.

This investigation includes two adjacent ecosystems -- Salt Fork Creek and Heritage Lake. A related objective of the current study is to collect sufficient information to evaluate the feasibility of potential remedial action alternatives for Landfills 1, 2, 3, and 4; Salt Fork Creek; and Heritage Lake, as necessary based on the results of the Landfills RI.

Conceptual Site Model Development

As previously stated, all of the analytical data and most of the geologic/hydrogeologic data collected doing the previous RI activities have been rejected due to concerns over data quality. As a result, a conceptual site model was developed to represent a hypothetical landfill that may be in hydraulic connection with an area creek and lake. Utilizing what data was "usable" and noting key observations for the Landfills, Salt Fork Creek, and Heritage lake, the diagram on Page 4 illustrates the Conceptual Site Model, including potential migration pathways.

• Landfill contaminants have migrated to soils and may have migrated to air, surface water, sediments, and groundwater.
• Landfill soils have become contaminated by contact with wastes.
• Soil particulants and volatile constituents may enter the air, where they may be transported relatively short distances by the wind.
• Contaminated surface soils and dissolved soil or waste contaminants also may be transported by surface runoff from the landfills.
• Runoff may enter Salt Fork Creek by a relatively direct route in the cases of Landfills 1 and 2, or through the surface water drainage system in the cases of Landfills 3 and 4.
• Contaminants in the creek may be adsorbed by sediments and/or transported by stream flow.
• Heritage Lake is at a higher elevation and should not receive runoff from any of the landfills.
• Because of the thin soil covers on the landfill and the shallow water table, leachate production within the landfills is likely to have occurred by rain infiltration, snow melt, and by leaching of submerged landfill contents.
• Seepage into surface water and into soils are anticipated.

Contaminant Exposure and Pathways

Base workers occasionally working on or near the landfills may be exposed to contaminants in surface soils or surface debris. The general public may be exposed to contaminated soils or surface debris during trespassing since the landfills are easily accessible from roads. Current farming activities on the periphery of Landfill 1 could also result in exposure to surface soils. Since the landfills support sucessional vegetative communities and a diverse community of wildlife, these plants and animals may potentially be exposed to soil contaminants.

All human and ecological receptors potentially exposed to contaminated groundwater will be evaluated as part of the risk assessment. Additional groundwater sampling of off-site private drinking water wells was conducted in March 1999; the Air Force Base is expected to provide those sampling results to the homeowners the first week in April.

Base workers occasionally working in or near Salt Fork Creek and Heritage lake may be exposed to contaminants in surface water and sediments. The general public may be exposed to contaminated surface water and sediments in Salt Fork Creek during recreational-type activities since the creek is easily accessible from roads and the Heritage Lake area. The general public may be exposed to contaminants in Hertiage Lake surface water and sediment during recreational activities permitted at the lake. Fish consumption is a possible exposure route for both Salt Fork Creek and Hertiage Lake. Plants and animals may potentially exposed to surface ater and sediment contaminants.

The general public could be exposed to leachate (a contaminated liquid resulting when water percolates, or trickles, through waste materials and collects components of those wastes) seeps along the banks of Salt Fork Creek since it is easily accessible; maintenance workers could occasionally be exposed to seeps. Since Salt Fork Creek supports a diverse community of wildlife, these plants and animals may potentially be exposed to leachate at and downstream of seep locations.

Receptors for each of the media discussed above may also be exposed to contaminants in the air. Receptors for surface and subsurface soils may be exposed to contaminants entering by volatilization and particulate emmisions from soils. Receptors for water pathways maybe exposed to contaminants entering air from volitization from water.

Contaminants of Concern

All detected organic compounds will be considered Contaminants of Concern (COCs) for the medium in which they are detected. Organic chemicals which could be present in the landfills include volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), chlorinated pesticides, polychlorinated biphenyls (PCBs), herbicides, and dioxins/furans.

Data for inorganic parameters will be compared to background concentrations. All detected inorganic parameters in Heritage Lake water and sediments will be considered potential COCs and carried through the risk assessment. If calucations show that any inorganic parameters appear to present unacceptable human health or ecological risk, further evaluaton will be undertaken to assess whether concentrations of these parameters in the lake exceed typical local levels. All inorganic parameters with maximum concentrations that exceed background upper tolerance limits will be considered potiential COCs for the human health and ecological risk assessments. Inorganic compounds which could be present in the landfills include metals.

Note: List of Potential Contaminants of Concern in Soil and Water found on page 7 of this Fact Sheet. (These listed chemicals have been detected in soil and water sampling conducted at the Landfills during the Spring of 1998.)

List of Potential Contaminants of Concern

Opportunities for Public Participation

Members of the community can become involved in the environmental program at the former Chanute Air Force Base by attending the Restoration Advisory Board (RAB) meetings which are held the Thursday of the first full week (which includes a Sunday) of every other month at 7:00 p.m. at the Rantoul Aviation Center. The RAB is an advisory group which acts as a focal point for the exchange of information between the Air Force, Illinois EPA, U.S. EPA, and the local community regarding restoration activities. The RAB is intended to bring together community members who reflect the diverse interests within that local community; the RAB is the vehicle to identify concerns, values, and needs between the affected community and the installation.

The next Chanute AFB RAB meeting is being held on April 8, 1999, at 7:00 p.m. at the Rantoul Aviation Center.

You are also invited to learn more about site history and activities by visiting the Information Repository located at the Base Library on the former Chanute Air Force Base. The Repository contains copies of the technical documents and summaries, fact sheets, news releases, the community relations plan, and other site-specific information.

For Additional Information