Record of Decision System (RODS)
SUSSEX COUNTY LANDFILL NO. 5
|Site Name:||SUSSEX COUNTY LANDFILL NO. 5|
|Address:||BETWEEN CNTY RD 494, CNTY RD 497, SH 24|
|City & State:||LAUREL DE 19956|
|NPL Status:||Deleted from the Final NPL|
|ROD Type:||Record of Decision|
|Media:||groundwater, drinking water|
|Contaminant:||VOCs, metals, vinyl chloride, benzene, 1, 2-dichlorpronane, 1, 4-dichlorobenzene|
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
The Sussex County Landfill #5 Superfund Site (Site), also known as the Laurel Landfill, is a 38-acre municipal landfill located off Route 494 and approximately 1 mile west of the Laurel Airport in Laurel, Delaware (see Figures 1 and 2). The landfill was in operation between May 1970 and August 1979 and during that time accepted municipal and industrial waste. Waste was disposed of at the landfill in trenches which were excavated into the native soil. At the start of the landfill operations, waste was disposed of in the extreme southern portion of the property with disposal progressing toward the northern property boundary. Waste placed in the trenches was covered by approximately two feet of soil obtained from soil stockpiles generated during the excavation of the trenches. After the landfill closed in 1979, a transfer station for municipal waste was operated under permit from Delaware Department of Natural Resources and Environmental Control (DNREC) on the northwest corner of the property. This transfer station closed in 1993.
The Site is bordered by property used predominantly for agricultural purposes. However, residential dwellings also exist along the roadways surrounding the landfill. There are approximately 5,000 people within a three-mile radius of the landfill and this entire population uses groundwater as its drinking water supply. The principal stream draining the Site is Broad Creek, which lies approximately two miles north of the Site. A surface water drainage ditch (the Collins and Culver Ditch) lies approximately 500 feet from the northeast corner of the landfill and discharges into Broad Creek.
During the 1980s, several investigations were conducted at the Site by Sussex County and DNREC to evaluate the potential impacts posed by contaminants of concern on groundwater and surface water quality in the vicinity of the Site. As a result of these investigations, DNREC determined that groundwater in the vicinity of the landfill had been impacted by contaminants coming from the landfill. Groundwater Management Zones (GMZs) were subsequently developed for the landfill and approved by DNREC. Three GMZs were established in the area surrounding the landfill; one of these restricted the installation of new groundwater pumping wells and two of these restricted pumping rates of any new and existing wells. On August 8, 1988, DNREC and Sussex County signed a Memorandum of Understanding (MOU) to support the development and implementation of the GMZs.
In 1986, EPA concluded a site inspection which indicated that groundwater in the area of the landfill had become contaminated with volatile organic compounds (VOCs) and metals coming from the landfill.
The Site was proposed for the National Priorities List (NPL) in June 1988 and was added to the list of October 4, 1989. On April 4, 1991, EPA and Sussex County entered into an Administrative Order on Consent which required Sussex County to conduct a Remedial Investigation (RI) and Feasibility Study (FS) for the Site.
During the RI, one offsite-residential well was found to be contaminated with vinyl chloride just above the Maximum Contaminant Level (MCL). As a result, Sussex County provided this residence with bottled water. In February of 1993, Sussex County installed a water treatment system on the well which uses a carbon filter to remove VOCs as well as ultraviolet light to reduce bacteria levels.
In the Fall of 1993, Sussex County completed the RI which included the EPA-prepared Human Health and Ecological Risk Assessments. Based on the results of the RI and the Risk Assessments, EPA determined that a FS was not necessary to evaluate remedial alternatives.
EPA has determined that no action is presently warranted at the Site under the Superfund Program based on: 1) the low levels of contamination detected in the groundwater and 2) the risk levels which were calculated for the Site.
In addition, in accordance with the MOU and a State Notice of Conciliation dated August 1994, Sussex County is required to install a water line which will serve residents downgradient of the landfill and within the GMZs with public water. The State Notice of Conciliation also provides for the following: 1) a groundwater monitoring program; 2) maintenance of the landfill cover to ensure the integrity and effectiveness of the soil cover and to correct any effects of settling, subsidence and erosion; and 3) institutional controls which restrict well installation and/or operation in the GMZs. These actions should ensure that the Site continues to pose no unacceptable risks to human health in the future.
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