FOCUSED REMEDIAL PLAN FORMER NEW HAVEN WATER COMPANY PROPERTY
HAMDEN, CONNECTICUT
Prepared For:
South Central Connecticut Regional Water Authority
August 2007 Revised: July 2013
Prepared By:
LEGGETTE BRASHEARS & GRAHAM, INC. Professional Groundwater and Environmental Engineering Services
4 Research Drive, Suite 301 Shelton, CT 06484
Prepared By: ________________________ Michael Manolakas, LEP, CPG Vice President
LEGGETTE, BRASHEARS & GRAHAM, INC.
TABLE OF CONTENTS
Page
1.0 INTRODUCTION ............................................................................................................1 2.0 PCB-IMPACTED AREA .................................................................................................1 3.0 SCOPE OF WORK ...........................................................................................................1 3.1 Public Notice .........................................................................................................1 3.2 Site Preparation .....................................................................................................2 3.3 Dust Control and Mitigation Procedures ..............................................................2 3.4 Protection of Site Infrastructure ............................................................................3 3.5 Excavation.............................................................................................................3 3.5.1 Overlying Soils .........................................................................................3 3.5.2 PCB Soil Removal ....................................................................................3 3.6 Post-Excavation Confirmation Sampling .............................................................4 3.7 Decontamination of Equipment ............................................................................4 3.8 Backfilling.............................................................................................................4 3.9 Waste Disposal......................................................................................................5 4.0 PROJECT TIMELINE ......................................................................................................5 5.0 REPORTING ....................................................................................................................5
LEGGETTE, BRASHEARS & GRAHAM, INC.
LIST OF FIGURES (at end of report)
Figure
1 Site Location Map 2 Cross-Section G-G’ 3 Cross-Section H-H’
PLATE (in pocket at end of report)
Plate
1 Distribution of Peak PCB Concentration
LEGGETTE, BRASHEARS & GRAHAM, INC.
FOCUSED REMEDIAL PLAN FORMER NEW HAVEN WATER COMPANY PROPERTY
HAMDEN, CONNECTICUT
1.0 INTRODUCTION
The following Focused Remedial Plan (FRP) was prepared by Leggette, Brashears &
Graham, Inc. (LBG) on behalf of the South Central Connecticut Regional Water Authority
(RWA). The FRP was prepared in accordance with Order No, SRD-128 for the site located at
550 Newhall Street in Hamden, Connecticut (figure 1). This preferred remedy was described in
the March 30, 2005 LBG report entitled, “Final Investigations and Remedial Evaluation Report
Former New Haven Water Company Property Hamden, Connecticut” (FIERA). The FRP details
the excavation and disposal of all soil and/or fill identified with concentrations of
polychlorinated biphenyls (PCBs) above 10 mg/kg (milligrams per kilogram) located at the
Former Middle School site (Site). Details of the remedial action are presented below.
2.0 PCB-IMPACTED AREA
Between 2002 and 2005, 629 soil and fill samples were analyzed for PCBs. The results
of the investigations are detailed in the 2005 FIERA. Plate 1 and figures 1 and 2 show the limits
of soils containing PCBs greater than 10 mg/kg at the Site. As shown, the isolated spill area is
located west of the former middle school on the northwestern side of the tennis and basketball
courts. The PCB-impacted materials above 10 mg/kg are contained in an approximate
400-square foot area and are located between 8 and 10 ft bg (feet below grade) (approximately
30 yards of material).
PCBs and PCB congeners have never been detected in the groundwater at the Site.
3.0 SCOPE OF WORK
3.1 Public Notice
Notice of this interim remedial action would be identified in a local newspaper of
substantial circulation and identified in a mailing to all abutting property owners.
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LEGGETTE, BRASHEARS & GRAHAM, INC.
3.2 Site Preparation
Prior to the initiation of active remediation, several tasks must be completed to prepare
the excavation area. These activities include the following:
A licensed surveyor will mark out the approximate limits of the excavation by
installing stakes or painting the ground surface;
Temporary chain-link security fence would be installed around the work zone. While not required by regulation, a “Mark ML” will be affixed to the security fencing; and
Protective rubber mats and hay bales will be placed on and around any storm drains
located within the work zone.
Entrance to the work zone would be restricted to Site workers meeting training and ongoing
medical surveillance program requirements in accordance with 29 CFR Part 1910. Upon
completion of the work day, the chain-link fencing surrounding the work zone would be pad
locked.
3.3 Dust Control and Mitigation Procedures
The following methods will be used to prevent conditions conducive to dust generation
and to suppress dust should it occur.
A water spray will be maintained onsite throughout the remedial activities. Water will be
applied to control dust as needed;
Traffic speed in the unpaved areas of the Site will be limited to a maximum of 5 miles per hour;
Exposed excavations, disturbed ground surfaces, and unpaved traffic areas will be wetted
as necessary to maintain a moist condition; Soil and/or fill stockpiles will be wetted as necessary to maintain a moist condition and
covered at the end of each work day; and All disturbed areas will be seeded following grading.
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LEGGETTE, BRASHEARS & GRAHAM, INC.
3.4 Protection of Site Infrastructure
As required by law, Call Before You Dig (CBYD) will be contacted prior to excavating
to confirm that utilities are not present in the excavation area. In the event utilities are identified
in the excavation areas, the utilities will be protected, relocated or removed. There are no above-
grade structures located in the vicinity of the excavation.
3.5 Excavation
3.5.1 Overlying Soils
Soils within the excavation footprint and overlying the soils targeted for offsite disposal
(those delineated to contain greater than 10 mg/kg of PCBs) will be excavated with a backhoe
and placed on plastic sheeting located within the work zone. The staged soils will be surrounded
by silt fencing or hay bales and the stockpile will be covered with plastic sheeting which would
be anchored to the ground or hay bales. Shallow soils that are removed from the first 2 feet will
be segregated from those removed from 2 to 8 ft bg.
In accordance with OSHA regulations, the stockpiles will be at least 2 feet from the edge
of the completed excavation1. All excavation sidewalls will be sloped into the base of the
excavation at a slope ratio no greater than 1 ½ to 1 (34 degrees)2.
3.5.2 PCB Soil Removal
Soils containing PCBs above 10 mg/kg were delineated to be contained between 8 and
10 ft bg. These soils will be excavated with a backhoe and live-loaded into trucks for offsite
disposal. The remedial excavation will follow protocols outlined in the LBG July 2004 Quality
Assurance Project Plan. A plastic sheet will be placed on the ground between the excavation and
the truck to ensure impacted soils do not spill onto the bare surface. Following this initial
removal activity, soil confirmation samples will be collected following protocols outlined in
Section 3.6. If the confirmation samples show soils containing PCBs above 10 mg/kg remain,
additional soils would be excavated as described above, and additional confirmation samples
1 OSHA, Specific Excavation Requirements, 29 CFR 1926.651(j)(2) outlines that excavated materials or equipment should be located at least 2 feet from the edge of excavations. 2 In accordance with OSHA Sloping and Benching (1926 Subpart P App B), maximum sloping of Class C soils at a ratio of 1 ½ to 1 (or 34 degrees from horizontal) is acceptable in excavations less than 20 feet deep. Sloping for excavations greater than 20 feet deep should be designed by a registered professional engineer.
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LEGGETTE, BRASHEARS & GRAHAM, INC.
would be collected. The remedial excavation will be deemed complete once all confirmation
results are at or below 10 mg/kg.
3.6 Post-Excavation Confirmation Sampling
Once the target soils are excavated, a minimum of two basal and eight sidewall samples
would be collected and analyzed for PCBs by EPA Method 8081. All samples would be
analyzed following Connecticut Department of Energy and Environmental Protection (CTDEEP)
Reasonable Confidence Protocols and will follow protocols outlined in the LBG July 2004
Quality Assurance Project Plan. Sidewall confirmation samples would be collected at a
minimum interval of 1 per 10 feet. Basal samples will be collected at a minimum frequency of
1 per 200 square feet.
3.7 Decontamination of Equipment
All equipment which comes into contact with the PCB-impacted soils will be
decontaminated. It is anticipated that this equipment would be limited to the excavator bucket
and possibly a hand auger. Decontamination procedures would initially involve wiping materials
with damp pads or towels. Decontamination will occur prior to backfilling, and backfilling will
not proceed until the equipment is shown to be free of PCBs. Wipe samples would be collected
following decontamination to ensure no PCBs remain on the equipment. If PCBs are detected on
the equipment, decontamination procedures would proceed as outlined in 40 CFR 761. All waste
materials would be disposed as described in Section 3.9.
3.8 Backfilling
The overlying soils removed from the upper 8 feet will be placed in the remedial
excavation hole. The soils removed from 2 to 8 feet will first be placed in the hole, followed by
the soils removed from the upper 2 feet. Clean backfill will be imported to the Site to complete
the backfilling of the excavation. All soils will be backfilled in approximate 1 foot lifts and
tamped with the excavator bucket. The final grade level will match pre-existing conditions. If
the excavation is completed sometime between spring and fall, grass seed and hay would be
placed in the excavation footprint. If the removal occurs in the winter, the area would be seeded
in the following spring.
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LEGGETTE, BRASHEARS & GRAHAM, INC.
3.9 Waste Disposal
All wastes will be transported and disposed of in accordance with applicable State and
Federal regulations. Final disposition of the soils has not been determined; however, all PCB
remediation waste will be disposed in a chemical waste landfill as identified in 40 CFR 761.
4.0 PROJECT TIMELINE
RWA will complete the aforementioned remedy within six months of CTDEEP approval
of the aforementioned remedial action plan.
5.0 REPORTING
After the excavation and offsite disposal actions are complete, a brief letter report will be
prepared documenting the following:
The objective of the excavation, the excavation methods and activities performed, and the volume of the excavated soil;
A map showing the approximate limits of the excavations and confirmation sample locations;
A copy of the waste disposal manifests; and
A copy of confirmation sample laboratory results.
H:\SCCRWA\Hamden MS\2013\PCB Focused Remedial Plan_7-23-13.doc
LEGGETTE, BRASHEARS & GRAHAM, INC.
FIGURES
LEGGETTE, BRASHEARS & GRAHAM, INC.
PLATE