Record of Decision System (RODS)
E.I. DU PONT DE NEMOURS & CO., INC. (NEWPORT PIGMENT PLANT LANDFILL)
|Site Name:||E.I. DU PONT DE NEMOURS & CO., INC. (NEWPORT PIGMENT PLANT LANDFILL)|
|Address:||JAMES & WATER STS|
|City & State:||NEWPORT DE 19804|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Media:||Soil, Sediment, GW, SW|
|Contaminant:||VOCs, Metals, Radioactive Materials|
|Abstract:||The 120-acre E.I. Du Pont, Newport site is located in Newport, New Castle County, Delaware. Land use in the area is predominantly industrial, with a paint pigment production facility (Ciba-Geigy plant), a chromium dioxide production facility (Du Pont Holly Run plant), two industrial landfills separated by the Christina River, a baseball diamond, and the nearby Koppers Superfund site. The site also contains two wetland areas designated as North and South, which encompass the floodplain area, and overlie the Columbia and Potomac aquifers. The pigment plant began manufacturing operations in 1902 to produce Lithopone, a white, zinc- and bariumbased inorganic paint pigment. In 1929, Du Pont purchased the site. Du Pont ceased production of Lithopone in 1952, but had begun producing other organic and inorganic pigments containing several metals. From 1961 to 1966, drums of thorium waste were disposed of in the North Landfill. These drums contained two to five percent thorium oxide bound to nickel as an off-specification product. However, EPA has determined that no removal or remediation of these drums is required since, due to the low solubility of thorium oxide, it is unlikely that there would by any migration of contaminants at any significant levels away from the landfill. In the 1970s, Du Pont constructed the Holly Run plant to expand its production of chromium dioxide. In 1984, Du Pont sold the pigment manufacturing operations to Ciba-Geigy Corporation, but retained the chromium dioxide production operations. These two plants were built on fill material placed over low-lying farmland. The fill is contaminated with heavy metals,including cadmium, lead, barium, and zinc. Pigment waste and off- specification products were disposed of in the North and South Landfills. The North Landfill was used for Lithopone waste, other organic pigment waste, chromium waste, and other miscellaneous waste from 1902 until 1974. The South Landfill, located in the South Wetlands, also was used for the disposal of Lithopone waste from 1902 until 1953. Neither of the landfills had a bottom liner. A small portion of the Ballpark appears to have become contaminated when contaminated soil from the pigment plant was used to groom the field. State investigations conducted in the late 1970s and 1980s, indicated elevated levels of heavy metals and VOCs in the onsite ground water. In 1993, EPA required Du Pont to address the seepage of a heat transfer fluid into the Christina River. During the RI/FS, Ciba-Geigy removed an underground storage tank used to store diesel fuel and repaired discharge piping to the river because cracks in the piping were allowing ground water infiltration, which led to discharge of zinc to the Christina River in excess of the Ciba-Geigy NPDES permit. Sediment contamination has been attributed to precipitation of contaminants from ground water as it discharges to the Christina River or the wetlands, direct dumping, and erosion and surface water runoff from the landfills. Surface water contamination has been attributed to the discharge of contaminated ground water and/or contact with contaminated sediment and source discharges from the Ciba-Geigy plant. This ROD addresses contamination at the Ballpark, North and South Landfills, North and South Wetlands, Christina River, and the Ciba-Geigy and Du Pont Holly Run plants as a final remedy. The primary contaminants of concern affecting the soil, sediment, ground water, and surface water are VOCs, including PCE and TCE; metals, including arsenic, chromium, and lead; and radioactive materials. SELECTED REMEDIAL ACTION: The selected remedial action for this site includes excavating approximately 1 yd of lead-contaminated soil above 500 mg/kg from the Ballpark, the top one foot of contaminated sediment from the North and South Wetlands, and the contaminated soil from the South Landfill that is located on Delaware property; disposing of the excavated soil and/or sediment from the Ballpark, North Wetlands, and Lithopone waste from piles near the North Landfill onsite in the North Landfill; disposing of the excavated sediment from the South Wetlands and the soil from the Delaware property portion of the South Landfill onsite in the South Landfill; treating contaminated soil in the South Landfill onsite using in-situ stabilization to reduce the ability of the metals to leach into the ground water, if determined necessary by TCLP and modified TCLP testing; capping the North and South Landfills tominimize continued ground water contamination; backfilling with clean fill and revegetating all excavated areas; constructing a physical barrier wall along the Christina River from the Ciba-Geigy plant to the North Landfill to limit migration of ground water to the river; installing extraction wells on the chemical plant side of the wall to recover and control mounding of ground water, followed by onsite treatment using air stripping to remove VOCs and precipitation to remove metals; restoring and monitoring the North and South Wetlands; dredging contaminated sediment from the Christina River, followed by onsite treatment by dewatering and/or stabilization, and onsite disposal in the North or South Landfills or offsite in an EPA-approved disposal facility; discharging treated effluent onsite to surface water or offsite to a POTW; backfilling dredged areas with clean fill; paving contaminated plant areas; developing and implementing erosion control, operations and maintenance, and waste management plans; monitoring ground water, surface water, and air; providing an alternate water supply to residences and businesses near the site; and implementing institutional controls, including deed and land use restrictions. The estimated present worth cost for this remedial action is $47,700,000, which includes an estimated annual O&M costof $18,607,000 for 30 years. PERFORMANCE STANDARDS OR GOALS: Chemical- specific sediment cleanup goals, based on toxicity tests and benthic studies, are cadmium 60 mg/kg; lead 1,200 mg/kg; and zinc 5,600 mg/kg. The chemical-specific soil excavation goal for the Ballpark is lead 500 mg/kg. ARAR waivers for technical impracticability and greater risk to human health and the environment were issued for the Columbia and Potomac aquifers, North and South Wetlands, and the Christina River because attempts to mitigate these areas would cause additional contamination, would adversely affect the wetlands around the South Landfill, or contamination from offsite sources would prevent attainment of ARARs. INSTITUTIONAL CONTROLS: Institutional controls, including deed and land use restrictions, will be implemented in the North Landfill, South Landfill, South Wetlands, and Ciba-Geigy and Du Pont Holly Run plants to ensure the protectiveness of the remedy, restrict future land use, notify the public of past land use, and limit future installation of drinking water wells.|
This remedy addresses soils, sediments, surface water, and ground water contamination at the Site. This is a final Record of Decision for the Site. The principal threats at this Site are contaminated soils containing hazardous substances at the north and south landfills and at the CIBA-GEIGY and the Du Pont Holly Run plants, and contaminated sediments containing hazardous substances in the north drainage way. Treatment is a major component of the remedy at the south landfill while containment is the major component at the other locations due to Site-specific conditions. Below is a summary of the selected remedy:
* Ballpark: Excavation of soils above 500 ppm lead with disposal in the north landfill.
* Purpose: Prevent human exposure to elevated levels of lead.
* North landfill: Capping; wetland remediation, restoration, and monitoring; vertical barrier wall down to base of the Columbia aquifer; and ground-water recovery and treatment.
* Purpose: Prevent continued releases of contaminants to the ground water which discharges to the river and the north wetlands, clean up areas of unacceptable environmental impact in the north wetlands, prevent exposure of plant and terrestrial life to contaminated soils.
* South landfill: Excavation and consolidation of contaminated soil underneath and to the east of Basin Road or South James Street onto the south landfill; in-situ soil stabilization of the combined soil; capping of the south landfill.
* Purpose: Prevent continued releases of contaminants to the ground water which discharges to the river and the south wetlands, prevent unacceptable human exposure to contaminated soils from the landfill.
* South wetlands: Excavation, restoration, monitoring.
* Purpose: Prevent unacceptable impacts to environmental receptors.
* Christina River: Dredging, monitoring.
* Purpose: Prevent unacceptable impacts to environmental receptors.
* CIBA-GEIGY and Du Pont Holly Run plants: Vertical barrier wall along the Christina River at the CIBA-GEIGY plant, pave the rest of the ground within the contaminated plant areas, recover and treat the ground water up-gradient of the barrier wall, institute special health and safety plans for intrusive work.
* Purpose: Prevent continued releases of contaminants to the ground water which discharges to the river, prevent unacceptable human exposure to contaminated soils.
* Ground water: Monitoring, provide public water supply along Old Airport Road, establish a ground water management zone.
* Purpose: Prevent human exposure to Siterelated contaminated ground water, prevent further contamination of the Columbia and the Potomac aquifers, protect the south wetlands.
The remedy for the ground water also includes invoking the "greater risk to human health and the environment" applicable or relevant and appropriate requirements (ARAR) waiver. This waiver applies to both the Columbia and Potomac aquifers. Attempts to remediate the Potomac aquifer will cause more contamination to migrate into the Potomac aquifer directly underneath the Site from the more highly contaminated Columbia aquifer. Attempts to remediate the Columbia aquifer will adversely affect the wetlands around the south landfill. These adverse effects outweigh the benefits of installing pump and treat systems in these aquifers. There is currently no human exposure to this ground water, nor is any expected to occur in the future. However, a long-term monitoring program will be instituted as part of this Record of Decision to make sure that this waiver continues to be justified. Appropriate remedial measures shall be taken if the monitoring data indicates a necessity to do so.
State of Delaware Surface Water Quality Standards (SWQSs) are being waived in the north wetlands and the river using the "technical impracticability" ARAR waiver because of off-site sources. Federal ambient water quality criteria are hereby being waived in the river for the same reason. SWQSs are also being waived in the south wetlands using the "greater risk to human health and the environment" waiver because compliance would require destruction of far more wetlands than is estimated necessary in order to protect the environment.
The total present worth cost of the selected remedy is approximately $47,700,000.
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