FINAL PLAN OF REMEDIAL ACTION FORMER KIRKWOOD HIGHWAY GULF STATION SITE OPERABLE UNIT 1 Former Kirkwood Highway Gulf Station Site Operable Unit 1 October 3, 2011 Wilmington, Delaware DNREC Project No. DE-1495 This Final Plan of Remedial Action (Final Plan) presents the Department of Natural Resources and Environmental Control's (DNREC's) determination that: The Proposed Plan for Operable Unit 1 (OU-1) requires the removal of an underground 1 ,OOO-galion heating oil storage tank, installation of a vapor barrier system beneath the proposed new building slab, capping of the site with asphalt and clean soil for landscaping areas, and restricting groundwater use until the petroleum related constituents have been satisfactorily remediated. The selected groundwater remedy will be addressed in the Proposed Plan for OU-2. Long term activities include maintenance of the vapor barrier system and its components, groundwater monitoring and cap maintenance. DNREC issued public notice of the Proposed Plan for the Site on August 29, 2011 and opened a 20-day public comment period, which ended on September 19,2011. The Proposed Plan requires the following cleanup actions for the Site: 1. Remove the 1,OOO-galion heating oil storage tank, and evaluate the second anomaly in accordance with the DNREC approved Contaminated Materials Management Plan (CMMP). 2. Install a sub-slab vapor barrier system consisting of sub-slab venting, a chemically resistant membrane vapor barrier with passive roof venting, prior to the construction of the new building in accordance with DNREC-SIRS Vapor Intrusion Guidance. The final DNREC approved barrier will conform to DNREC's Vapor Policy, Brownfield Remedial Design and Action Work Plan Guidance, Appendix C; and Vapor Barrier Checklist. 3. Maintain the asphalt and landscaping cap, vapor barrier and its components in accordance with a DNREC approved Long Term Stewardship (LTS) plan.
Transcript
FINAL PLAN OF REMEDIAL ACTION
FORMER KIRKWOOD HIGHWAY GULF STATION SITE OPERABLE UNIT 1
Former Kirkwood Highway Gulf Station Site Operable Unit 1 October 3, 2011 Wilmington, Delaware DNREC Project No. DE-1495
This Final Plan of Remedial Action (Final Plan) presents the Department of Natural Resources and Environmental Control's (DNREC's) determination that: The Proposed Plan for Operable Unit 1 (OU-1) requires the removal of an underground 1,OOO-galion heating oil storage tank, installation of a vapor barrier system beneath the proposed new building slab, capping of the site with asphalt and clean soil for landscaping areas, and restricting groundwater use until the petroleum related constituents have been satisfactorily remediated. The selected groundwater remedy will be addressed in the Proposed Plan for OU-2. Long term activities include maintenance of the vapor barrier system and its components, groundwater monitoring and cap maintenance.
DNREC issued public notice of the Proposed Plan for the Site on August 29, 2011 and opened a 20-day public comment period, which ended on September 19,2011. The Proposed Plan requires the following cleanup actions for the Site:
1. Remove the 1,OOO-galion heating oil storage tank, and evaluate the second anomaly in accordance with the DNREC approved Contaminated Materials Management Plan (CMMP).
2. Install a sub-slab vapor barrier system consisting of sub-slab venting, a chemically resistant membrane vapor barrier with passive roof venting, prior to the construction of the new building in accordance with DNREC-SIRS Vapor Intrusion Guidance. The final DNREC approved barrier will conform to DNREC's Vapor Policy, Brownfield Remedial Design and Action Work Plan Guidance, Appendix C; and Vapor Barrier Checklist.
3. Maintain the asphalt and landscaping cap, vapor barrier and its components in accordance with a DNREC approved Long Term Stewardship (LTS) plan.
4. Record an environmental covenant consistent with Delaware's Uniform Environmental Covenants Act, UECA (Title 7, Del. Code Chapter 79 and Subtitle II). The environmental covenant will limit the site use to commercial development, prohibit land disturbing activities without DNREC's prior written approval and reference the establishment of a Groundwater Management Zone (GMZ) at the Site.
5. DNREC will extend a local GMZ to include the Site. The GMZ will ensure that no groundwater wells shall be installed and no groundwater shall be withdrawn from any well, on the Site, without the prior written approval ofDNREC-SIRS.
6. Maintain the monitoring wells installed on-site in order to complete the additional groundwater assessment and monitoring.
7. Gasoline related impacts to groundwater, including groundwater monitoring will be addressed in the QU-2 Proposed Plan, under the regulatory requirements of the DNRECTMS and DNREC-SIRS.
The Proposed Plan also includes the location of additional information found on the DNREC web page and in the DNREC office at Lukens Drive in New Castle.
There were no comments or questions from the public regarding the Proposed Plan. Therefore, the Proposed Plan was adopted as the Final Plan (see attached).
Approval: This Final Plan meets the requirements of the Hazardous Substance Cleanup Act.
g{J~fr-rr~ Imothy Ratsep, Program Admlllistrator
Division of Waste and Hazardous Substances
KLT:tlw; KLTlI017.doc/DE-1495 II B-9
PROPOSED PLAN OF REMEDIAL ACTION OPERABLE UNIT 1
(Site Soils)
Former Kirkwood Highway Gulf Station Site Wilmington, New Castle County, Delaware
DNREC Project No. DE-1495
August 2011
Delaware Department of Natural Resources and Environmental Control Division of Waste and Hazardous Substances
Site Investigation & Restoration Section 391 Lukens Drive
New Castle, Delaware 19720
CONTENTS
• Proposed Plan: Questions and Answers • Figures 1-3 • Glossary of Terms • Attachment: What is a Proposed Plan?
PROPOSED PLAN OF REMEDIAL ACTION OPERABLE UNIT 1
(Site Soils)
Former Kirkwood Highway Gulf Station Site Wilmington, New Castle County, Delaware
DNREC Project No. DE-1495
Approval: This Proposed Plan meets the requirements of the Hazardous Substance Cleanup Act.
t. 2~. 1/
Date
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PROPOSED PLAN
Questions & Answers
Former Kirkwood Highway Gulf
Station Site OU-1
What is the Former Kirkwood Highway Gulf Station Site, Operable Unit 1? The Former Kirkwood Highway Gulf Station Site is the location of a former Gulf/Cumberland Farms gasoline station with an auto repair garage and a food convenience store (see Figure 1). OU-1 consists of the site soils and OU-2 consists of the site’s groundwater. A separate Proposed Plan will be developed and public noticed for OU-2. The Site is located at the northwest corner of the intersection of Limestone Road and Kirkwood Highway. The Site is a certified Brownfield and is being developed for use as a commercial bank.
Tax Parcel Number: 08-044.30-067 Address: 4601 Kirkwood Highway, Wilmington, Delaware Nearest major intersection: Limestone Road and Kirkwood Highway Area: 1.02 acres Surrounding Property: Surrounding land use is commercial Zoning: CR-UDC (Commercial Regional) Site Utilities: Public water and sewer are provided Surface water: Mill Creek is the nearest surface water body and is located approximately 2,100 feet east of the Property. Topography: The Site is located in the “Fall Zone” where Piedmont plains transition into the Coastal Plain. The site is relatively flat with elevations ranging from 85 to 90 feet above mean sea level (NAVD83) Groundwater: Groundwater flow is to the south-southwest
What happened at the Former Kirkwood Highway Gulf Station Site? The Site was a former gasoline station that included fuel islands and underground storage tanks. An automobile service garage was also present at the Site. Underground storage tanks and service lines released petroleum products into the groundwater and soil. What is the environmental problem at the Former Kirkwood Highway Gulf Station Site? Shallow groundwater and soil at the Site have been impacted by petroleum as a result of the operations in the past. The concentrations of petroleum constituents identified in the soils are acceptable for use of the site for commercial purposes. A Brownfield Investigation of the Property identified groundwater contamination on the Property
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impacted with benzene, MTBE, 2-methylnaphthalene, and naphthalene. The concentrations of these respective volatile and semi-volatile organic compounds also exceed permissible vapor intrusion screening levels. The DNREC-Tank Management Section is overseeing routine quarterly groundwater monitoring events being performed by the responsible party, Cumberland Farms. What does the owner want to do at the Former Kirkwood Highway Gulf Station Site? The proposed redevelopment plan includes the demolition of the current service station garage and construction of a drive-thru branch bank.
A copy of the proposed development plan is included in Figure 3. What clean-up actions have been taken at the former Former Kirkwood Highway Gulf Station Site? Approximately 2,028 tons of petroleum impacted soils were over-excavated following the removal of three 10,000-gallon gasoline underground storage tanks (UST). To increase oxygen levels and promote biodegradation, approximately 990 pounds of calcium peroxide was distributed in the excavation bottom. The underground hydraulic lifts and heating oil USTs have also been removed. A 10,000-gallon diesel UST was removed in 2001 along with approximately 20 cubic yards of impacted soil. What additional clean-up actions are needed at the former Former Kirkwood Highway Gulf Station Site? DNREC has separated the site into two (2) Operable Units, OU-1 and OU-2. Two (2) subsurface anomalies were identified during a geophysical survey as part of the investigation. One anomaly is likely an underground 1,000-gallon heating oil storage tank and will be removed, while the other anomaly is unknown and will be further explored and removed, if necessary. DNREC’s clean-up plans include installing a vapor barrier system beneath the proposed new building slab. The site will be re-graded as per the redevelopment plans and capped with asphalt and clean soil for landscaping areas. Groundwater will be restricted at the Property until the petroleum related constituents have been satisfactorily remediated. The selected groundwater remedy will be addressed in the Proposed Plan for OU-2. Long term activities include maintenance of the vapor barrier system and its components, groundwater monitoring and cap maintenance.
The following cleanup actions are proposed for the Site: 1. Remove the 1,000-gallon heating oil storage tank, and evaluate the second anomaly in accordance with the DNREC approved Contaminated Materials Management Plan (CMMP). 2. Install a sub-slab vapor barrier system consisting of sub-slab venting, a chemically resistant membrane vapor barrier with passive roof venting, prior to the construction of the new building in accordance with DNREC-SIRS Vapor Intrusion Guidance. The final DNREC approved barrier will
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conform to DNREC’s Vapor Policy, Brownfield Remedial Design and Action Work Plan Guidance, Appendix C; and Vapor Barrier Checklist. 3. Maintain the asphalt and landscaping cap, vapor barrier and its components in accordance with a DNREC approved Long Term Stewardship (LTS) plan. 4. Record an environmental covenant consistent with Delaware’s Uniform Environmental Covenants Act, UECA (Title 7, Del. Code Chapter 79 and Subtitle II). The environmental covenant will limit the site use to commercial development, prohibit land disturbing activities without DNREC’s prior written approval and reference the establishment of a Groundwater Management Zone (GMZ) at the Site. 5. DNREC will extend a local GMZ to include the Site. The GMZ will ensure that no groundwater wells shall be installed and no groundwater shall be withdrawn from any well, on the Site, without the prior written approval of DNREC-SIRS. 6. Maintain the monitoring wells installed on-site in order to complete the additional groundwater assessment and monitoring. 7. Gasoline related impacts to groundwater, including groundwater monitoring will be addressed in the OU-2 Proposed Plan, under the regulatory requirements of the DNREC-TMS and DNREC-SIRS.
What are the long term plans for the Site after the cleanup? The future use of the site is to remain commercial. After redevelopment, a DNREC approved Long Term Stewardship (LTS) plan, which is to include groundwater monitoring, will be implemented and continued until remediation objectives are met.
DNREC plans to issue a Certificate of Completion of Remedy for OU-1 of the site after the completion of the clean-up, the redevelopment of the property, the submittal of a DNREC approved LTS plan, and the implementation of the uniform environmental covenants at the site.
How can I find additional information or comment on the Proposed Plan?
The complete file for the site, including the Brownfields Investigation, is available at the DNREC office, 391 Lukens Drive in New Castle. Most documents are also found on:
http://www.nav.dnrec.delaware.gov/DEN3/
The 20-day public comment period begins on August 31, 2011 and ends at close of business (4:30 pm) on September 19, 2011. Please send written comments to the DNREC office or call Ms. Kristen Thornton, Project Manager, at: 302-395-2600.
Figures:
Figure 1: Location Map Figure 2: Site Photos Figure 3: Development Plan
Brownfield Property that is vacant or underutilized because of the
perception or presence of an environmental problem. Certified Brownfield A Brownfield that DNREC has determined is eligible for
partial funding through the Delaware Brownfields Program. Contaminant of Concern (COC) These are potentially harmful substances at concentrations
above acceptable levels (i.e. metals and PAH). Certificate of Completion of Remedy (COCR)
A formal determination by the Secretary of DNREC that remedial activities required by the Final Plan of Remedial Action have been completed.
*Exposure Contact with a substance through inhalation, ingestion, or direct contact with the skin. Exposure may be short term (acute) or long term (chronic).
Final Plan of Remedial Action DNREC’s proposal for cleaning up a hazardous site after it has been reviewed by the public and finalized.
Hazardous Substance Cleanup Act (HSCA)
Delaware Code Title 7, Chapter 91. The law that enables DNREC to identify parties responsible for hazardous substances releases and requires cleanup with oversight of the Department.
Human Health Risk Assessment (HHRA)
An assessment done to characterize the potential human health risk associated with exposure* to site related chemicals.
Proposed Plan of Remedial Action A plan for cleaning up a hazardous site submitted by DNREC and subject to public comments.
Risk Likelihood or probability of injury, disease, or death. Risk Assessment Guidance for Superfund (RAGS)
An EPA guidance document for superfund sites
Site Specific Assessment (SSA) and Site Inspection (SI)
Environmental studies of a site including sampling of soils, groundwater, surface water, sediment and/or wastes on the property.
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What is a Proposed Plan?
A Proposed Plan of Remedial Action (Proposed Plan) is a summary of how DNREC plans to clean up a contaminated site. A Final Plan of Remedial Action (Final Plan) is the adoption of the Proposed Plan, after all comments made by the public within the comment period of twenty days have been considered and addressed by DNREC. The Delaware State Legislature passed the Hazardous Substance Cleanup Act (HSCA) in 1990. The Legislature made sure that members of the public would be informed about environmental problems in their own neighborhoods and have a chance to express their opinion concerning the clean up of those environmental problems before DNREC takes action. After DNREC studies a site, it summarizes the problems there and proposes one or more possible solutions in a Proposed Plan. The Proposed Plan contains enough information to allow lay persons to understand the site. More detailed information can be found in the reports and documents approved by DNREC. All of the documents and reports created by DNREC or consultants during the course of the investigation of the site are available to the public at the offices of DNREC-SIRB or at DNREC’s website:
DNREC issues the Proposed Plan by advertising it in at least one newspaper in the county where the site is located. The legal notices for the Proposed Plans and the Final Plans usually run on Wednesdays or Sundays in the legal classified section of the News Journal and/or the Delaware State News. The public comment period begins on the day (Wednesday), or the day after (Sunday) the newspaper publishes the legal notice for the Proposed Plan. DNREC frequently holds public meetings during the comment period. Those meetings are usually held near the site in the evening. Citizens can request a public meeting if DNREC did not already schedule one. Comments are collected at the public meetings, by phone or in writing. DNREC considers all comments and questions from the public before the Proposed Plan is finalized and adopted as a Final Plan.
