Record of Decision System (RODS)
|Site Name:||HIMCO DUMP|
|Address:||COUNTY ROAD 10 AND NAPANEE EXTENSION|
|City & State:||ELKHART IN 46514|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Media:||VOCs, Other Organics, Metals, Inorganics|
|Abstract:||The 100-acre Himco Dump site is an active municipal landfill in Elkhart, Elkhart County, Indiana. Land use in the area is predominantly agricultural, residential, and light industrial, with a wetland area located west of the site. The site is bounded by woodlands and the northernmost extent of a gravel pit pond to the north; by County Road 10 and private residences to the south; by the Nappanee Street Extension to the east; and a section of land west of two ponds to comprise the west. From 1960 to 1976, the Himco site operated as a solid waste landfill. Refuse was placed directly onto the ground surface or disposed of in unlined trenches. In 1971, the State identified the Himco site as an open dump. In1974, residents near the site complained about color, taste, and odor problems with the ground water from their shallow wells, and samples from these wells were found to be highly contaminated with manganese. By 1990, the wells showed high concentrations of sodium, which posed a chronic health threat to the residents. Residents with wells that were affected by site contamination were connected to the municipal water supply. In 1976, the landfill was closed and covered with approximately one foot of sand overlying a calcium sulfate layer. In 1984, EPA inspections identified that ground water downgradient of the site was contaminated by VOCs, SVOCs, and metals. Leachate seeps also were observed at the site. During the RI, a "hot spot" was identified at the southwest border of the landfill, which showed high levels of VOC contamination. In 1992, as part of an emergencyremoval action, EPA located and PRPs removed and disposed of seventy-one 55- gallon drums offsite. Although other hot spots have not been identified to date, it is not certain whether additional drum pockets exist onsite. This ROD addresses the contaminated surface and subsurface soil in the southern portion of the landfill. The primary contaminants of concern affecting the soil and debris are VOCs, including PCE, TCE, toluene, and xylenes; other organics, including PAHs and phenols; metals, including arsenic and lead; and other inorganics, including cyanide. SELECTED REMEDIAL ACTION: The selected remedial action for this site includes installing a composite barrier cap with a vegetative layer over 58 acres of the site, with an active vapor phase carbon system to treat off-gases from the landfill; providing for a contingent remedy to install a ground flare system, if landfill gas characterization studies indicate VOC emissions exceed ARARs; mitigating any affected wetlands; monitoring ground water; and implementing institutional controls, including deed, ground water, and land use restrictions, and site access restrictions such as fencing. The estimated present worth cost for this remedial action is $11,821,000, which includes an estimated annual O&M cost of $210,000 for 30 years. PERFORMANCE STANDARDS OR GOALS: Not provided. INSTITUTIONAL CONTROLS: Deed, ground water, and land use restrictions will be implemented to prevent future land use and to restrict ground water use in the site vicinity.|
The purpose of this remedy is to eliminate or reduce migration of contaminants to the groundwater and to reduce the risks associated with exposure to the contaminated materials.
The major components of the selected remedy include:
- Construction of a composite barrier, solid waste landfill cover (cap);
- Use of institutional controls on landfill property to limit land and groundwater use;
- Installation of an active landfill gas collection system including a vapor phase carbon system to treat the off-gas from the landfill; An enclosed ground flare system will be implemented if landfill gas characterization studies indicate VOC emissions exceed ARARs (Indiana Administrative Code 326 IAC); and
- Monitoring of groundwater to ensure effectiveness of the remedial action and to evaluate the need for future groundwater treatment.
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