Record of Decision System (RODS)
KEYSTONE SANITATION LANDFILL
|Site Name:||KEYSTONE SANITATION LANDFILL|
|City & State:||UNION TOWNSHIP PA 17331|
|NPL Status:||Currently on the Final NPL|
In 1982, in accordance with State permitting requirements, groundwater monitoring for volatile organic compounds (VOCs) was conducted. VOC contamination was detected in on-site monitoring wells and in a nearby spring, Mundorff Spring, which is located east of the Site.
In April 1984, an EPA Field Investigation Team performed a site investigation in response to citizens' complaints of groundwater contamination in residential wells. Sampling results from the Pennsylvania Department of Environmental Resources (PADER), the predecessor to the Pennsylvania Department of Environmental Protection (PADEP), and the Environmental Protection Agency (EPA) confirmed the presence of low levels of VOC contamination in some of the residential wells.
In August 1984, the owner of the landfill installed a spray irrigation system in the most contaminated groundwater area to prevent the migration of contaminants off-site and to remove VOC from the groundwater. Spray irrigation is a practice consisting of spraying contaminated groundwater on a field and allowing VOCs to evaporate into the air. The spray irrigation system was opened until 1992. In addition, leachate collection was attempted on the southern side of the landfill along Line Road. Two perforated pipes were located at the base of the landfill. The pipe ran parallel to Line Road and discharged into a storage tank. The storage tank was pumped periodically, and the contents were disposed off-site.
In the spring of 1985, the State of Maryland installed monitoring wells at the Maryland border to monitor potential contaminant migration. Low levels of VOC contamination have been consistently detected in at least one of these wells.
The Keystone Sanitation Landfill Site was placed on the Superfund National Priorities List (NPL) in July 1987. This list includes sites where uncontrolled hazardous substance releases present the most significant potential threats to human health and the environment.
In 1987, EPA began a Remedial Investigation (RI) and Feasibility Study (FS) at the Site. The RI field activities began in the spring of 1989. The RI/FS reports were issued in July 1990 and finalized in September 1990. EPA issued the OU-1 ROD on September 30, 1990. The remedy selected in the OU-1 ROD included:
- Installation and maintenance of an impermeable cap and gas collection system over the 40-acre landfill
- Installation and maintenance of on-site groundwater extraction wells and a treatment plant to capture, contain and reduce the concentrations of VOCs and metals in groundwater
- Provision of a point-of-use groundwater treatment system to on-site residents
- Installation and maintenance of a fence around the Site
- Monitoring of the groundwater in monitoring and residential wells
- Monitoring of surface water and sediments
- Initiation of institutional controls regarding present and future activities on the landfill property
To date, the fence and the on-site point-of-use groundwater treatment system have been completed. Construction of the extraction wells and groundwater treatment plant has recently been completed. EPA expects the plant will begin operating later this year.
In addition, the 1990-ROD included a requirement to perform another RI to further study the groundwater contamination in the off-site residential wells and off-site monitoring wells. This RI was completed in January 1998. During the second investigation, EPA collected groundwater samples from 72 monitoring wells, sampled 74 residential wells, and sampled surface water and sediment at numerous locations. Based on the results of the second RI, the ROD was amended on June 25, 1999 to address groundwater contamination outside the boundaries of the landfill. As required by the June 25, 1999 Amendment, carbon filtration units have been offered to residents within 3/4 miles of the landfill. To date, filters have been installed to all eligible residents who accepted the offer.
The main components of the selected remedy include the following: installation and operation of offsite extraction wells to capture, contain, and remediate contaminated groundwater emanating from the landfill to levels that comply with groundwater cleanup standards; installation of filters for current and future residences located north of the tributary to Piney Creek and within a ? mile radius from the landfill. A filter will also be installed for one residence located within the ? mile to one-mile radius because of a finding of unacceptable current risk; annual monitoring of current and future residential wells north of the tributary to Piney Creek and within ? mile to one mile from the center
of the landfill, with provision of filters for residences within this radius if monitoring shows two consecutive exceedances of any cleanup standard; if filters are provided as part of this remedy, the residence will not be included in this annual monitoring; evaluation for inclusion in the monitoring program for homes greater than one mile from the center of the landfill if site-related contamination is detected nearby; provision of filters to such residence if the residential well is adjacent to the one-mile border, within the same hydrogeologic flowpath; and two
consecutive samples exceed a cleanup standard for a site-related contaminant of concern; preparing a hydrogeological evaluation report after five years of data collection; and sampling of surface water and sediment from local tributaries.
In addition, this amended Record of Decision (ROD) includes certain modifications to the performance standards/cleanup standards for the onsite pump and treat system selected in the Operable Unit (OU) 1 ROD issued in 1990, which interrelates with the off-site response actions selected herein. These amendments do not address and/or otherwise pertain to the landfill cap and associated source control measures selected in the OU1 ROD.
Under this selected remedy, levels of site-related contamination in the groundwater will be decreased to reduce the health risk to residents that live in close proximity to the site. The main goals of this amendment are to capture, contain, and remediate offsite groundwater contamination emanating from the landfill to levels that will attain the cleanup standards and protect nearby residents by installing filters and monitoring groundwater. In combination with the planned remedial actions selected in the OU1 ROD, this remedy will satisfy the remedial objectives for this site and be effective in capturing, containing, and remediating the contaminants in the groundwater to the cleanup standards while protecting both human health and the environment.
Estimated Capital Costs: Not Provided
Estimated Annual O&M Costs: Not Provided
Estimated Present Worth Costs: $1,833,485
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