PCB Focused Remedial Plan 7-23-13 Focused... · FOCUSED REMEDIAL PLAN FORMER NEW HAVEN WATER COMPANY PROPERTY HAMDEN, CONNECTICUT ... 2 In accordance with OSHA Sloping and Benching

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


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


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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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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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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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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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.

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PCB Focused Remedial Plan 7-23-13 Focused... · FOCUSED REMEDIAL PLAN FORMER NEW HAVEN WATER COMPANY PROPERTY HAMDEN, CONNECTICUT ... 2 In accordance with OSHA Sloping and Benching