VELSICOL CHEMICAL CORPORATION
[a/k/a VELSICOL CHEMICAL CORPORATION (MARSHALL PLANT)]
MARSHALL, CLARK COUNTY, ILLINOIS
The U.S. Environmental Protection Agency (USEPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) requested that the Illinois Department of Public Health (IDPH) evaluate the public health significance of current site conditions at the Velsicol Chemical Corporation site. On May 12, 1995, ATSDR released a public health assessment (PHA) for this site prepared by IDPH. To prepare this health consultation, IDPH reviewed the historical and environmental data since the release of the PHA.
The Velsicol Chemical Corporation (VCC) site is an 86-acre parcel consisting of a former production facility and an area formerly known as the 5/6 Pond. Several ponds were located on the site, but no longer exist. The site is in Clark County, about 1 mile north of Marshall, Illinois, along State Highway 1 (Attachment 1). The parcel is within the boundary of the former 420-acre VCC property (Attachment 2). About 334 acres of the property are currently leased for crop farming.
The site is in an agricultural area that includes several rural homes. It is bordered by a railroad right-of-way to the southeast and by pasture and agricultural fields to the south, west, and north. An unnamed tributary of East Mill Creek borders a southern portion of the site. Five homes are west and within 0.5 miles of the site (1).
The former VCC manufacturing facility produced a variety of resins, solvents, rubber extenders, and termiticides. Hazardous wastes generated from various manufacturing activities at the site were stored in on-site impoundments. In the past, overflow from these impoundments resulted in releases to the unnamed tributary of East Mill Creek. Process wastewater was deep-well injected on the site and most of the waste solids and sludges generated at the facility were disposed in the 5/6 Pond.
VCC has been the subject of several past investigations. In 1982, VCC was identified as a federal Superfund project and subsequently placed on the National Priorities List. The results of the 1986-1987 remedial investigation showed contamination of:
- groundwater beneath the facility;
- soils in the plant area;
- on-site impoundment water and sediments;
- off-site groundwater;
- subsurface soil; and
- creek water, sediments, and fish.
The contaminants included inorganic chemicals and volatile and semi-volatile organic chemicals, including pesticides and heavy metals.
VCC ceased operations at the Marshall facility on August 30, 1988. After closing, VCC removed all chemicals from the facility and demolished the remaining structures. A Record of Decision and Consent Decree was signed in 1988 that outlined several remedial activities be performed including:
- excavating contaminated soil and sediments from the plant property, ponds (except the 5/6 Pond), and the creek bed (both on and off the site);
- relocating the creek;
- consolidating and stabilizing contaminated materials on the surface of the 5/6 Pond;
- capping the 5/6 Pond; and
- installing a groundwater pump-and-treat system (1).
As contaminated areas were remediated, the property area producing contaminated runoff dwindled, as did the need for underground injection. Velsicol plugged and abandoned the underground injection control well in September 1993 . Under the terms of the Consent Decree, VCC was required to implement and maintain an interim groundwater monitoring program (GMP) for the downgradient side of the VCC facility until May 1995. At that time a long-term monitoring program replaced the interim GMP. Currently, the long-term program includes monitoring of groundwater elevations, collection of groundwater samples, surface water monitoring, and groundwater treatment system monitoring. The results are reported to the Illinois Environmental Protection Agency (IEPA) annually.
IDPH staff revisited the site on March 29, 2001. Although the site was surrounded by a fence, three gates were open. The entrance gate opened to a gravel road that led to the groundwater treatment facility east of the former 5/6 Pond. This is the only building remaining on the site.
The groundwater treatment facility is built over an in-ground tank structure formally known as the railroad sump. Contaminated groundwater coming from the former 5/6 Pond landfill and the former 2 and 4 Ponds collects in an interceptor trench along the east side of the former 5/6 Pond landfill and along the northeast corner of the former Pond 4. Ponds 2 and 4 are now part of the south stormwater management zone (Attachment 2).
Contaminated groundwater is pumped from the collection drain through a buried forcemain into an air stripper, then bag-filtered and passed through granular activated carbon adsorption units. The treated groundwater is discharged to the City of Marshall's wastewater treatment plant.
Soil erosion was observed on the former 5/6 Pond's western berm with the deepest erosion gully at a depth of about 8 inches near the middle of the berm.
Chemicals of Interest
IDPH compared the maximum level of each chemical detected during environmental sampling with appropriate screening values to select chemicals for further evaluation for both carcinogenic and non-carcinogenic health effects (Attachment 3). Chemicals that exceeded comparison values and those for which no comparison value exists were selected as chemicals of interest for further evaluation.
The comparison values are used only to screen for chemicals of interest and do not represent the level at which health effects might occur. Though some of these chemicals may exist at levels greater than comparison values, they can only affect someone who is exposed and receives a high enough dose for adverse effects to occur. The amount of the contaminant, the duration and route of exposure, and the health status of exposed individuals are important factors in determining the potential for adverse health effects.
During the 1999 long-term treatment monitoring program, eleven groundwater monitoring wells were sampled quarterly. Groundwater flow is in a southwesterly direction beneath the site. Volatile organic chemicals (VOCs) were detected in nine of the forty groundwater samples collected. The locations of the wells are shown in Attachment 2. Methylene chloride was detected at 21.4 and 256 parts per billion (ppb) in well G203M during sample round two and sample round four. In sample round three, 1,2-dichloroethane was detected in well G215M at 10.4 ppb . Both contaminants were detected at levels greater than their comparison value of 5 ppb.
Overall, the 1999 groundwater sampling results do not suggest any change in the site conditions or further impact to groundwater quality beneath the site, with the exception of 1,1,2,2-tetrachloroethane detected during sampling round four at 98.5 ppb in well G220L. Because G220L is a background monitoring well about 1,200 feet upgradient from the former waste areas and no detections have occurred historically, the detection of 1,1,2,2-tetrachloroethane in G220L is considered irregular and does not represent true aquifer site conditions.
The nearest private wells are about 0.5 miles west of the site. Perimeter on-site monitoring wells show that the groundwater contamination is contained under the boundaries of the former production facility within the 420-acre VCC property.
Surface water samples have been collected at the site boundary where the unnamed tributary of East Mill Creek crosses under Township Road. No VOCs were detected in the surface water samples. The water quality within the unnamed tributary is not affected by contaminated groundwater at the site.
Groundwater Treatment System
The groundwater treatment system was monitored quarterly to evaluate its performance. Both influent and effluent samples were collected. The untreated groundwater sample results showed the VOCs benzene, carbon tetrachloride, chloroform, and toluene in all four sampling rounds.
Each of these VOCs were detected in the influent of all four sampling rounds concentrations of these compounds decreased after treatment. Carbon tetrachloride and chloroform were detected at low levels in the effluent during sampling round one. After the granular activated carbon in the adsorption units was replaced, subsequent rounds of sampling did not detect VOCs in the effluent. During 1999, the total volume of groundwater treated was 308,400 gallons and the mass of VOCs removed was 6.4 pounds . The treated water is discharged to the City of Marshall treatment works.
Adverse health effects may occur when a contaminant reaches a receptor population through an exposure pathway. An exposure pathway consists of a source of contamination, environmental media and transport mechanisms, a point of exposure, and a receptor population. Exposure to a contaminant may have occurred in the past, may be occurring now, or may occur in the future. When all these elements linking the contaminant source to an exposed population are known, a completed exposure pathway exists. When one of these elements is missing, a potential exposure pathway exists.
At the VCC site, no completed pathway exists. Remedial action, including the groundwater treatment system, is reducing contaminated groundwater at the site.
Child Health Initiative
IDPH recognizes that children are especially sensitive to some contaminants, so we include children when evaluating exposures to contaminants. IDPH does not anticipate that children will be exposed to contaminants in the groundwater at this site.
Under current site conditions, IDPH concludes that the VCC site currently poses no public health hazard. Future exposure will be avoided if no shallow groundwater wells are developed for use on the site, and the former 5/6 Pond landfill cap is maintained. Continued monitoring will determine if 1,1,2,2-tetrachloroethane, found only once in a background monitoring well, is present in the aquifer and moving toward the site.
IDPH recommends that IEPA continue to ensure that VCC maintains an adequate cap on the former 5/6 Pond landfill, continues long-term groundwater monitoring, and restricts site access. IEPA will enforce these recommendations as stated in the consent order.
Cary L. Ware
Illinois Department of Public Health
- Agency for Toxic Substances and Disease Registry. Public Health Assessment for Velsicol Chemical Corporation Site (Marshall, Illinois). Atlanta: U.S. Department of Health and Human Services; May 12, 1995.
- Illinois Environmental Protection Agency. RCRA Compliance Evaluation Inspection Report for the Velsicol Chemical Corporation Marshall Site. April 26, 1995.
- Memphis Environmental Center Incorporated. 1999 Annual Report Long-Term Treatment Monitoring Program for Velsicol Marshall Plant Site, Marshall, Illinois. Memphis, Tennessee, May 2000.
Environmental Media Evaluation Guides (EMEGs) are developed for chemicals based on their toxicity, frequency of occurrence at National Priorities List (NPL) sites, and potential for human exposure. They are not action levels but are comparison values. They are developed without consideration for carcinogenic effects, chemical interactions, multiple route exposure, or exposure through other environmental media. They are very conservative concentration values designed to protect sensitive members of the population.
Reference Dose Media Evaluation Guides (RMEGs) are another type of comparison value. They are developed without consideration for carcinogenic effects, chemical interactions, multiple route exposure, or exposure through other environmental media. They are very conservative concentration values designed to protect sensitive members of the population.
Cancer Risk Evaluation Guides (CREGs) are estimated contaminant concentrations based on a probability of one excess cancer in a million persons exposed to a chemical over a lifetime.
Maximum Contaminant Levels (MCLs) have been established by USEPA for public water supplies to reduce the chances of occurrence of adverse health effects from use of contaminated drinking water. These standards are well below levels for which health effects have been observed and take into account the financial feasibility of achieving specific contaminant levels. These are enforceable limits that public water supplies must meet.
Lifetime Health Advisories for drinking water (LTHAs) have been established by USEPA for drinking water. They represent the concentrations of chemicals in drinking water that are not expected to cause any adverse, non-carcinogenic effects over a lifetime of exposure. These are conservative values that incorporate a margin of safety.
This Velsicol Chemical Corporation Health Consultation was prepared by the Illinois Department of Health under Cooperative Agreement with the Agency for Toxic Substances and Disease Registry. It is in accordance with approved methodology and procedures existing at the time the Health Consultation was initiated.
Gail D. Godfrey
Technical Project Officer
SPS, SSAB, DHAC
The Division of Health Assessment and Consultation (DHAC), ATSDR, has reviewed this Health Consultation and concurs with its findings.
Chief, SSAB, DHAC, ATSDR