FIVE-YEAR REVIEW REPORT

RI02942F

or

 i ^' - 1

FIVE-YEAR REVIEW

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

RESPONSE ACTION CONTRACT (RAC), REGION I

For

U.S. Environmental Protection Agency

By

Tetra Tech NUS, Inc.

EPA Contract No. 68-W6-0045

EPA Work Assignment No. 123-FRFE-0133

TtNUS Project No. N4254

September 2002

TETRA TECH NUS, INC.
FIVE-YEAR REVIEW REPORT

F. O'CONNOR SUPERFUND SITE

AUGUSTA, MAINE

Prepared by:

U.S. Environmental Protection Agency

Region I

Boston, Massachusetts

I.

Richard C^vagnero, Acting Director

Office of Site Remediation and Restoration

Date
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION 1

1 CONGRESS STREET, SUITE 1100

BOSTON, MASSACHUSETTS 02114-2023

MEMORANDUM

DATE:

SUBJ:

FROM:

THRU:

TO:

September 13, 2002

Five- Year Review

F O'Connor Superfund Site

Nancy

Terrence Connelly

i ' ' A>, , . , ' //

Mary Jane O'Donnjjl, Chief '

ME, VT, and CT Superfund Section

Richard Cavagnero, Acting Dir&fyorj'/Y/

OSRR **'' ' l

Summary of Action

Attached for your review and signature is the first five-year review report for the F O'Connor

Superfund Site, the ("Site") in Augusta, Maine This review covers all three operable units of the

Site EPA Region 1 conducted this review pursuant to CERCLA section 121 (c), National Oil and

Hazardous Substances Pollution Contingency Plan (NCP) section 300.430(f)(4)(ii), and OSWER

Directives 9355 7-02 (May 23, 1991), and 9355.7-02A (July 26, 1994). This is a statutory

review, conducted for post-October 17, 1986 Remedial Actions The purpose of a five-year

review is to ensure that a remedial action remains protective of human health and the

environment

Major Issues

No major issues were identified in the five-year review process An analysis of the technical

practicability of restoring the groundwater beneath the site to drinking water quality within a

reasonable timeframe was underway prior to the start of the review EPA has determined that it is

technically impracticable from an engineering perspective to attain federal and state drinking

water standards for a limited portion of the Site, and is thus waiving attainment of these ARARs

for that portion of the Site (A ROD amendment documenting this change is being prepared for

signature within the next two weeks)
The five-year review process revealed that the remedies for all three operable units have been

implemented in accordance with the requirements of the 1989 ROD, as modified by the 1994

ESD and 1995 contingency remedy.

The remedial action for source control (OU-1) has been completed and is protective of human

health and the environment. Exposure pathways that could result in unacceptable risk are being __

controlled. The fmalization of the O&M plan will ensure that the OU-1 remedy will remain

protective.

The remedy for management of migration (OU-2) is protective of human health and the

environment. For a limited portion of the site, because of the presence of residual oil in the

subsurface and PCB and VOC concentrations that can not meet ROD target cleanup levels, a

technical impracticability waiver has been granted. Ongoing oil recovery and institutional controls

ensure that exposure pathways that could result in unacceptable risk are being controlled.

The remedy at OU-3 is expected to be protective of human health and the environment upon

completion of the 10-year sampling program. In the interim, exposure pathways that could result

in unacceptable risks are being controlled. Current data indicate that PCB concentrations in the

sediments of Riggs Brook are slightly above the trigger level in isolated and sporadic occurrences

Fish tissue PCB concentrations have remained below the ROD target goal,

Headquarters Perspective/Involvement

Headquarters provided comments on the draft five-year review report as part of its review of all

five-year reviews following the June 2001 guidance document "Comprehensive Five-Year

Guidance", OSWER No. 9355.7-03B-P. These comments have been addressed.

Public Involvement

EPA issued a press release on May 8, 2002 that was published in the Kennebec Journal

announcing EPA's review of the progress of the O'Connor Site cleanup. The press release

encouraged public participation. There is no established Community Advisory Group. To date

EPA, Maine DEP and Central Maine Power (PRP) have encountered little participation or

involvement from the local community. All site-related documents are available at the Lithgow

Public Library in Augusta. According to staff at the library there has been limited use of the

documents A notice which briefly summarizes this five-year review will be published in a major

local newspaper of general circulation.

Media-Congressional Involvement

There has been no media or congressional involvement regarding the five-year review process.

State Coordination

Maine DEP has participated in the review process, including the site inspection, interviews, and
has provided comments on the draft five-year review report. Maine DEP expressed concerns

over the fmalization of the O&M plan, and requested specific language regarding the status of

institutional controls and target cleanup goals. These concerns have been addressed in the final

report.

Recommendation

The selected remedy is protective of human health and the environment. Therefore, we

recommend you sign this five-year review.

Contact Persons

Nancy Smith, Work Assignment Manager, 918-1436

Terrence Connelly, Remedial Project Manager, 918-1373

Attachment: Five-Year Review Report
RI02942F

FIVE-YEAR REVIEW REPORT

FIVE-YEAR REVIEW

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

RESPONSE ACTION CONTRACT (RAC), REGION I

For

U.S. Environmental Protection Agency

By

Tetra Tech NUS, Inc.

EPA Contract No. 68-W6-0045

EPA Work Assignment No. 123-FRFE-0133

TtNUS Project No. N4254

September 2002

Phoebe Apall George D(/Gardner, P.E.

Project-Manager Program Manager
TABLE OF CONTENTS

FIVE-YEAR REVIEW REPORT

FIVE-YEAR REVIEW

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

SECTION PAGE

ES-1 EXECUTIVE SUMMARY E-1

1.0 INTRODUCTION 1-1

2.0 SITE CHRONOLOGY 2-1

3.0 BACKGROUND 3-1

3.1 Physical Characteristics 3-1

3.1.1 Setting 3-1

3.1.2 Topography 3-1

3.1.3 Subsurface Conditions 3-1

3.2 Land and Resource Use 3-4

3.3 History of Contamination 3-5

3.4 Initial Response 3-5

3.5 Basis for Taking Action 3-6

4.0 REMEDIAL ACTIONS 4-1

4.1 Remedy Selection 4-1

4.1.1 Source Control 4-1

4.1.2 Management of Migration 4-2

4.2 Remedial Implementation 4-3

4.2.1 Source Control (OU-i) 4-3

4.2.2 Management of Migration (OU-2) 4-5

4.2.3 Riggs Brook (OU-3) 4-7

4.3 System Operations/O&M 4-7

5.0 PROGRESS SINCE LAST 5-YEAR REVIEW 5-1

6.0 FIVE-YEAR REVIEW PROCESS 6-1

6.1 Administrative Components 6-1

6.2 Community Notification and Involvement 6-1

6.3 Document Review 6-1

6.4 Data Review 6-2

6.4.1 Source Control OU-1 6-2

6.4.2 Management of Migration OU-2 6-2

6.4.3 Riggs Brook OU-3 6-4

6.5 Site Inspection 6-5

6.6 Interviews . 6-6

RI02942F -j- Tetra Tech NUS, Inc.
TABLE OF CONTENTS (Cont'd)

FIVE-YEAR REVIEW REPORT

FIVE-YEAR REVIEW

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

SECTION PAGE

7.0 TECHNICAL ASSESSMENT 7-1

7.1 Question A: Is the Remedy Functioning as Intended by the Decision

Documents? 7-1

7.1.1 OU-1: Source Control Remedial Action 7-1

7.1.2 OU-2: Management of Migration 7-3

7.1.3 OU-3: Riggs Brook 7-4

7.2 Question B: Are the Exposure Assumptions, Toxicity Data, Cleanup

Levels and Remedial Action Objectives (RAOs) Used at the Time of

Remedy Selection Still Valid? 7-6

7.2.1 OU-1: Source Control Remedial Action 7-6

7.2.2 OU-2: Management of Migration 7-8

7.2.3 OU-3: Riggs Brook 7-10

7.3 Question C: Has Any Other Information Come to Light That Could Call

into Question the Protectiveness of the Remedy? 7-11

7.3.1 OU-1: Source Control Remedial Action 7-11

7.3.2 OU-2: Management of Migration 7-11

7.3.3 OU-3: Riggs Brook 7-12

7.4 Technical Assessment Summary 7-12

7.4.1 OU-1: Source Control Remedial Action 7-12

7.4.2 OU-2: Management of Migration 7-13

7.4.3 OU-3: Riggs Brook 7-13

8.0 ISSUES 8-1

9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS 9-1

10.0 PROTECTIVENESS STATEMENTS 10-1

11.0 NEXT REVIEW 11-1

TABLES

NUMBER PAGE

2-1 Chronology of Site Events 2-1

3-1 Contaminants of Concern At Site 3-8

4-1 Annual System Operations/O&M Costs - OU-1 4-9

RI02942F -II- Tetra Tech NUS, Inc.
TABLE OF CONTENTS (Cont'd)

FIVE-YEAR REVIEW REPORT

FIVE-YEAR REVIEW

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

FIGURES

NUMBER PAGE

3-1 Site Location Map 3-2

3-2 Site Features 3-3

4-1 Site Plan 4-4

APPENDICES

A Document Review List/References

B Site Inspection Report

C Site Interview List

D ARARs and TBCs

E Declaration Of Restrictive Covenant And Map Showing Area Covered By

Covenant

F MEDEP Comments, dated August 9, 2002, on the Draft Five Year Review Report

RI02942F -jji- Tetra Tech NUS, Inc.
ACRONYMS

AOC Administrative Order by Consent

ARAR Applicable or Relevant and Appropriate Requirement

AWQC Ambient Water Quality Criteria

CD Consent Decree

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CFR Code of Federal Regulations

CMP Central Maine Power Company

CMR Code of Maine Rules

cPAHs carcinogenic polyaromatic hydrocarbons

CSF Cancer Slope Factor

CWA Clean Water Act

ESD Explanation of Significant Differences

HA health advisory

IEUBK Integrated Exposure Uptake Biokinetic Model

IRIS Integrated Risk Information System

MCL Maximum Contaminant Level

MEDEP Maine Department of Environmental Protection

MEGs Maximum Exposure Guidelines

MOM Management of Migration

MRSA Maine Revised Statutes Annotated

MW Monitoring Well

NCP National Contingency Plan

ND non detect

NEPA National Environmental Policy Act

NOAA National Oceanic and Atmospheric Administration

NPL National Priorities List

NRPA Natural Resources Protection Action

OU Operable Unit

O&M Operations and Maintenance

PCBs Polychlorinated biphenyls

ppb parts per billion

ppm parts per million

PRP Potentially Responsible Party

RI02942F Tetra Tech NUS, Inc.
ACRONYMS (Cont'd)

RAGS Remedial Action Guidelines

RAO Remedial Action Objectives

RfDs USEPA Risk Reference Doses

RI/FS Remedial Investigation/Feasibility Study

ROD Record of Decision

RP Responsible Party

RSOW Remedial Design/Remedial Action Revised Statement of Work

SARA Superfund Amendment Reauthorization Act

SC Source Control

SCRA Source Control Remedial Action

SDWA Safe Drinking Water Act

Site O'Connor Company Superfund Site

SOW Statement of Work

TBC To Be Considered

Tl Technical Impracticability

TtNUS Tetra Tech NUS, Inc.

TSCA Toxic Substances Control Act

TWA Transformer Work Area

ug/L micrograms per liter

USEPA United States Environmental Protection Agency

VER vacuum enhanced recovery

VOC volatile organic compound

W&C Woodard & Curran Inc.

RI02942F -II- Tetra Tech NUS, Inc.
EXECUTIVE SUMMARY

A five-year review was performed for the F. O'Connor Superfund Site in Augusta, Maine, as

required by CERCLA when hazardous waste is left onsite, which does not allow unrestricted

use of a site. The purpose of the five-year review was to assess whether the remedy selected

for the Site remains protective of human health and the environment.

The 1989 Record of Decision selected a remedy to address the risks present at the Site

resulting from the operation of a salvage and electrical transformer recycling business. The

remedy for the O'Connor Superfund Site (Site) consists of three operable units (OUs). The

Source Control remedy (OU-1) specified in the 1989 Record of Decision (ROD) was changed in

an Explanation of Significant Differences (ESD) in 1994. The Source Control remedial action

included excavation and off site disposal of soils and sediments that exceeded target cleanup

levels, implementation of institutional controls, treatment of surface waters on the Site and site

restoration. Restoration activities included installation of a vegetated cover over the excavated

areas and reconstruction of wetland areas. The Source Control remedial action was completed

on November 11, 1997. The trigger for this five-year review was the start of source control

activities in August 1996.

The Management of Migration (MOM) remedy is separated into OU-2 for groundwater and OU-3

for Riggs Brook sediment. The OU-2 activities are ongoing and consist of institutional controls,

oil recovery, and groundwater monitoring. Vacuum enhanced recovery of residual oil from the

Transformer Work Area (TWA) II area has been used to remove free oil from groundwater

monitoring wells. Groundwater wells around the perimeter of the Site meet the target cleanup

goals. Concentrations of VOCs and PCBs in groundwater meet the target cleanup goals

throughout most of the Site. The OU-3 remedy includes ten years of annual monitoring of Riggs

Brook sediment and periodic biota sampling. Biota results have been below the target level;

sediment results have shown sporadic exceedances of the PCB threshold level that would

trigger an evaluation of the need for further remedial action.

The five-year review process revealed that the remedies for all three operable units have been

implemented in accordance with the requirements of the ROD, as modified by the ESD and

contingency remedy. The remedy for OU-2 is not protective in the TWA II/TI zone of the Site. A

ROD amendment is underway to address the issues covered in the Tl Waiver. Excluding the

TWA II area, the remedy is functioning as designed. A restrictive covenant signed by Central

RI02942F E-1 Tetra Tech NUS, Inc.
Maine Power (CMP) and MEDEP in 1994 restricts certain actions on the Site without written

approval from MEDEP. Although this covenant is held in escrow by MEDEP and therefore there

is some question as to its enforcement, CMP has complied with the restrictions and

consequently, the threat to exposure to contaminated groundwater has been prevented.

Achievement of groundwater cleanup goals in the TWA II area will be addressed in the ROD

amendment and revised Consent Decree/Statement of Work (CD/SOW).

Five-Year Review Protectiveness Statements:

• OU-1: The remedial action for OU-1 has been completed and is protective of human

health and the environment. Exposure pathways that could result in unacceptable risk

are being controlled. The finalization of the O&M plan will ensure that the OU-1 remedy

will remain protective.

• OU-2: The remedy at OU-2 is protective of portions of the Site. It is not protective of the

TWA II area and surroundings as defined as the Tl Zone in the Tl Waiver due to the

presence of residual oil in the subsurface and PCB and VOC concentrations that can not

meet target cleanup levels. Actions now underway to implement the Tl Waiver are

needed to ensure protectiveness.

• OU-3: The remedy at OU-3 is expected to be protective of human health and the

environment upon completion of the 10-year sampling program. In the interim, exposure

pathways that could result in unacceptable risks are being monitored. Current data

indicate that PCB concentrations in the sediments of Riggs Brook are slightly above the

trigger level in isolated and sporadic occurrences.

RI02942F E-2 Tetra Tech NUS, Inc.
Five-Year Review Summary Form

SITE IDENTIFICATION

Site name (from WasteLAN): O'Connor Co.

EPA ID (from WasteLAN): MED980731475

Region: 1

SITE STATUS

State: ME [ City/County: Augusta/Kennebec

NPL status: Final

Remediation status (choose all that apply): Operating (OU2&OU3) Complete (OU1)

Multiple OUs?* YES Construction completion date:

Has site been put into reuse? NO

REVIEW STATUS

Lead agency: EPA

Author name: Terrence Connelly

Author title: Remedial Project Manager Author affiliation: EPA Region I

Review period:** 3/1/02 to 9/30/02

Date(s) of site inspection: 5/21/02

Type of review: Post-SARA

Review number: 1 (first)

Triggering action:

OU1 Commencement of SCRA

Triggering action date (from WasteLAN): 7/30/1996

Due date (five years after triggering action date): 7/30/01***

* "OU" refers to operable unit.

** [Review period should correspond to the actual start and end dates of the Five-Year Review

in WasteLAN.]

*** The five-year review was scheduled to begin in August 2001 but was delayed until January

2002 due to a change in EPA project managers.

RI02942F E-3 Tetra Tech NUS, Inc.
Five-Year Review Summary Form, cont'd.

Issues:

• OU-2 cleanup goals not achievable in TWA II area.

• Riggs Brook sediments have not attained target cleanup levels.

• Shortfall in wetland restoration acreage.

• 1992 MEG for PCBs lower than ROD target cleanup level for PCBs.

• Reevaluate groundwater use restrictions.

Recommendations and Follow-up Actions:

• Amend ROD to reflect Tl Waiver and changes to OU-2 ARARs.

• Continue sediment monitoring program per ROD.

• Continue wetland monitoring.

• Analyze groundwater at lower PCB DL to evaluate if Site can attain lower 1992 MEG.

• Restructure Institutional Controls for long-term protectiveness.

Protectiveness Statement(s):

OU-1: The remedial action for OU-1 has been completed and is protective of human health and

the environment. Exposure pathways that could result in unacceptable risk are being controlled.

The finalization of the O&M plan will ensure that the OU-1 remedy will remain protective.

OU-2 : The remedy at OU-2 is protective in portions of the Site. It is not protective in the TWA

II area and surroundings defined as the Tl Zone in the Tl Waiver due to the presence of residual

oil in the subsurface and PCB and VOC concentrations that can not meet target cleanup levels.

Actions now underway to implement the Tl Waiver are needed to ensure protectiveness.

OU-3: The remedy at OU-3 is expected to be protective of human health and the environment

upon completion of the 10-year sampling program, and in the interim, exposure pathways that

could result in unacceptable risks are being monitored. Current data indicates that PCB

concentrations in the sediments of Riggs Brook are slightly above the trigger level in isolated

and sporadic occurrences.

Other Comments:

RI02942F E-4 Tetra Tech NUS, Inc.
1.0 INTRODUCTION

The purpose of this five-year review is to determine if the remedy selected for the F. O'Connor

Superfund Site (Site) in Augusta, Maine, is protective of human health and the environment.

This report summarizes the five-year review process, investigations and remedial actions

undertaken at the Site, evaluates the monitoring data collected, discusses any issues identified

during the review, and presents recommendations to address them.

The United States Environmental Protection Agency, Region 1 (USEPA) is preparing this fiveyear review pursuant to the Comprehensive Environmental Response Compensation, and

Liability Act (CERCLA) §121 and the National Contingency Plan (NCP). CERCLA §121 states:

"If the President selects a remedial action that results in any hazardous substances,

pollutants, or contaminants remaining at the site, the President shall review such

remedial action no less often than each five years after the initiation of such remedial

action to assure that human health and the environment are being protected by the

remedial action being implemented. In addition, if upon such review it is the judgment of

the President that action is appropriate at such site in accordance with section [104] or

[106], the President shall take or require such action. The President shall report to the

Congress a list of facilities for which such review is required, the results of all such

reviews, and any actions taken as a result of such reviews."

The USEPA interpreted this requirement further in the National Contingency Plan; 40 CFR

§300.430(f)(4)(ii) states:

"If a remedial action is selected that results in hazardous substances, pollutants, or

contaminants remaining at the site above levels that allow for unlimited use and

unrestricted exposure, the lead agency shall review such action no less often than every

five years after the initiation of the selected remedial action."

The remedy for the Site was separated into three operable units:

• OU-1 Source Control

• OU-2 Management of Migration

• OU-3 Riggs Brook

The Source Control Remedial Action (SCRA) at OU-1 was completed in November 1997.

Remedial actions at OU-2 and OU-3 are ongoing. A review of all three operable units is

included in this report.

RI02942F 1-1 Tetra Tech NUS, Inc.
This is the first five-year review for the O'Connor Company Site. The triggering action for this

statutory review is the commencement of SCRA activities in August 1996. Actions related to

OU-2 (MOM) and OU-3 (Riggs Brook) commenced in October 1996. The five-year review is

required since contamination remains at the Site above levels that allow for unrestricted use and

exposure. The five-year review was scheduled to begin in August 2001 but was delayed until

January 2002 due to a change in EPA project managers.

EPA has conducted this five-year review of the remedial actions implemented at the O'Connor

Site in Augusta, Maine. Tetra Tech NUS, Inc. (TtNUS) supported USEPA in completion of the

review under RACI Contract No. 68-W6-0045, W.A. No. 123-FRFE-0133. The work assignment

began in March 2002 and will be completed in October 2002. Assistance was provided by the

Maine Department of Environmental Protection (MEDEP), Central Maine Power Co. (CMP) and

Woodard & Curran, Inc. (W&C), consultants working for CMP. As referenced in the 1991

Consent Decree, CMP participated in the five-year review process. W&C on behalf of CMP

provided draft portions of the Five-Year Review Report to USEPA. W&C completed draft

portions of the report between January and April 2002. The review was completed in

accordance with USEPA Guidance OSWER No. 9355.7-03B-P.

RI02942F 1-2 Tetra Tech NUS, Inc.
2.0 SITE CHRONOLOGY

TABLE 2-1

CHRONOLOGY OF SITE EVENTS

FIVE-YEAR REVIEW REPORT

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

DATE

Early 1950s

Feb1972

1 978 & 1982

1982-1984

Sept8, 1983

Dec 21, 1984

April 1985

May 13, 1986

May 19, 1986

June 23, 1986

May 23, 1987

June 15, 1989

Sept 27, 1989

SeptS, 1991

June 1994

July 11, 1994

Oct20, 1994

October 10, 1995

July 1996

Aug - Oct 1 996

Oct1996

Oct 1996

Jan -May 1997

May-Nov 1997

Nov. 11, 1997

Aug - Oct 2001

April 2002

August 2002

EVENT

F. O'Connor Co. begins operating a salvage and electrical transformer recycling

business on the site.

Oil spill on site found to have migrated toward Riggs Brook.

MEDEP conducts additional sampling events at the site, identifies polychlorinated

biphenyl (PCB) contamination.

USEPA conducts sampling events at the site, confirms PCB contamination.

Site placed on National Priorities List (NPL)

USEPA issues Unilateral Administrative Order to O'Connor Co. requiring it to fence

5 acres of the Site and sample and analyze all drums and tanks on the site.

USEPA notifies O'Connor and Central Maine Power of their potential responsibility

for contamination at the Site.

O'Connor and CMP voluntarily enter into an Administrative Order by Consent

(AOC) with USEPA to conduct a Remedial Investigation and Feasibility Study

(RI/FS) at the Site.

MEDEP issues an Administrative Order to O'Connor designating the Site an

Uncontrolled Hazardous Substance Site under Maine law.

MEDEP issues an AOC to O'Connor and CMP

USEPA and MEDEP issue an amended AOC to O'Connor and CMP. Order

extends Site limits to approximately 9 acres.

CMP submits a draft RI/FS to USEPA and MEDEP for review.

ROD issued by USEPA.

CD between USEPA and CMP signed.

MEDEP and CMP sign a Declaration of Restrictive Covenant.

ESD signed.

Revised Statement of Work (RSOW) issued

USEPA invokes the contingency remedy.

Source Control 100% Design completed

Phase I of Source Control completed (OU-1)

First sampling of OU-3, Riggs Brook sediment

Phase I Vacuum Enhanced Recovery (VER) (pilot) completed (OU-2)

Phase II VER completed (OU-2)

Phase II of Source Control completed (OU-1)

Source Control Remedial Action completed

Phase III VER completed (OU-2)

Draft Tl Evaluation Report submitted to USEPA and MEDEP for OU-2 Management

of Migration.

Completion of First Five- Year Review

RI02942F 2-1 Tetra Tech NUS, Inc.
3.0 BACKGROUND

3.1 Physical Characteristics

3.1.1 Setting

The F. O'Connor Superfund Site property consists of approximately 23 acres within a 28-acre

property and is located on U.S. Route 17 approximately three miles east of the Kennebec River

in Augusta, Maine. The surrounding area is generally rural. The property is bordered on the

east and southeast by Riggs Brook, a small northerly flowing tributary of the Kennebec River, on

the north and west by woodlands, and on the south by Route 17. The property south of Route

17 is generally wooded. A residence abuts the CMP property along its western boundary. The

land at the Site was used as farmland until the 1950s when the F. O'Connor Company

established a salvage yard and transformer recycling operation at the Site. The MEDEPdesignated Hazardous Substance Site consists of the same 23 acres within the 28-acre

property. The location of the property is shown on Figure 3-1.

3.1.2 Topography

The Site is located on a ridge that transects the Site in a generally northeast-southwest

direction. An access road splits the Site from southwest to northeast. North and west of the

road, the Site is relatively level, with a low swampy area known as the Upland Marsh. East and

south of the road the topography slopes sharply toward Riggs Brook, with a change in elevation

of approximately 50 feet. Three water bodies are located on the Site, all of which were created

by operations of the F. O'Connor Co. and later reconstructed during the SCRA. The

approximately 2-acre Upland Marsh drains to a channel that flows to the Upper and Lower

Lagoons and on to the Riggs Brook wetlands. Figure 3-2 shows these features and Site

topography.

3.1.3 Subsurface Conditions

The overburden soils at the Site generally consist, from surface to depth, of glacial marine silts

and clays, glacial till, and bedrock. The clay tends to be absent only in areas of shallow

bedrock. During source control, approximately 20,000 tons of soil and sediment with PCB

concentrations greater than 10 ppm were excavated and disposed offsite. Another 3,000 tons,

RI02942F 3-1 TetraTechNUS, Inc.
FEET

SOURCE: WOODWARD & CURRAN

SITE LOCATION MAP FIGURE 3-1

O'CONNOR COMPANY SUPERFUND SITE - FIVE-YEAR REVIEW

AUGUSTA, MAINE

DRAWN BY D.W MACDOUGALL

CHECKED BY P CALL

SCALE. AS NOTED

REV

TETRA TECH NUS, INC.

DATE. JULY 5, 2002

NAME. DWG\4254\0600\FIG_3-1 DWG

55 Jonspin Road Wilmington, MA 01887

(978)658-7899

RI02942F 3-2 Tetra Tech NUS Inc
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with PCB levels less than 10 ppm, were consolidated onsite in one area, identified as the

Designated Area (see Figure 3-2). Approximately 24,000 cubic yards of clean soil (PCBs less

than 1 ppm) were imported to the Site to restore the excavated area to approximate the original

grade and to provide a 12-inch soil cover over the entire Designated Area.

Bedrock drilling completed during site investigations indicated mostly competent rock with very

few recognizable fractures. Bedrock outcrops are found in the areas of transformer work area

(TWA) I and III (see Figure 3-2).

The principal groundwater migration pathway on the Site is a discrete zone within the till along

the top of the bedrock surface. Groundwater flow from the Upland Marsh (a large recharge

basin) is confined and channeled through the bedrock trough in the bedrock saddle centered

immediately northeast of the Upper Lagoon. The bedrock flow regime has very little water in

storage. The vertical permeability of the bedrock is believed to be very low, creating a "quasi"

perched condition of the overburden groundwater flow system. At the southeastern end of the

Site, near Riggs Brook, the potentiometric surface of the bedrock groundwater is above the

ground surface. MW-106B in this area is a free-flowing artesian well. (W&C, 2000).

3.2 Land and Resource Use

The Site is currently a mix of forest and open field, bordering the Riggs Brook wetland. The

open fields encompass the formerly contaminated areas and the three reconstructed wetlands

on the Site (Upland Marsh, Upper Lagoon, and Lower Lagoon). The Site is no longer secured

with perimeter fencing and is not actively used by CMP. Surrounding land uses include lowdensity residential, light agricultural, fields, and forest. Current zoning maps and land use

ordinances were obtained from the Augusta City Services Department. The upland portion of

the Site is zoned as RRES - rural residential district, where residential development that

conserves the rural character of the area is permitted. The portion of the Site that slopes down

toward Riggs Brook is zoned LR - limited residential district. The LR district is suitable for

residential and recreational development. The wetland area that surrounds Riggs Brook is

zoned RP - resource protection district, where development would adversely affect water

quality, productive habitat, biological ecosystems, or areas with scenic and natural values. (City

of Augusta, ME Land Use Ordinance)

RI02942F 3-4 TetraTechNUS, Inc.
Natural resources on the O'Connor property include both terrestrial and aquatic habitats. Riggs

Brook is not navigable in the vicinity of the Site, but large wetland areas in the Riggs Brook

watershed have been mapped by the MEDEP. The Riggs Brook wetlands are considered to be

shrub swamps, consisting of a mix of woodlands and emergent aquatic vegetation and peat. No

rare or endangered species have been identified in wetland or woodland habitats associated

with the Site. The Riggs Brook wetlands lie in a Zone A according to the City of Augusta Flood

Insurance Rate Map (230067 0011 C), revised June 15, 1994. Zone A is a special flood hazard

area inundated by 100-year flood where no base flood elevations have been determined. There

are no other specified flood hazard zones covering the balance of the Site.

There are no mapped sand or gravel aquifers in the vicinity of the Site. Bedrock wells were

historically used for domestic water in the area, however public water is now available

throughout the area.

3.3 History of Contamination

The F. O'Connor Company operated a salvage yard for the dismantling and recycling of

electrical transformers and capacitors on the Site from the early 1950s until the late 1970s. This

resulted in drippage and spillage of oil to the ground, principally in the vicinity of the transformer

work areas (TWAs). Soil and groundwater contamination primarily consisted of PCBs with

some volatile and semi-volatile organic compounds, and inorganics. Potential sources of

contamination that were identified on the Site included three TWAs, scrap piles, oil storage

tanks, and two lagoons installed to help control oil migration from this Site.

3.4 Initial Response

The first report of contamination was due to an oil spill on the Site in February 1972, which was

investigated by MEDEP. Later that year MEDEP requested the O'Connor Company contain all

transformer fluids in above ground storage tanks to prevent spills.

In 1976 MEDEP conducted further investigations at the Site, and asked the O'Connor Company

to construct two surface water lagoons on the Site to control migration of oils. The next year,

MEDEP requested that the Company discontinue use of the lagoons and reclaim the area.

Water from the lagoons was pumped into storage tanks and the sediments were excavated and

RI02942F 3-5 Tetra Tech NUS, Inc.
placed in a low area near the gravel access road. The sediments were underlain and covered

by one-foot of clay soil. Placement of this soil created a barrier to surface water runoff, and

resulted in the creation of the Upland Marsh.

The Site was proposed for inclusion on the NPL in December 1982, and placed on the final NPL

on September 8, 1983. In April of 1985 the F. O'Connor Company and CMP were notified of

their potential liability for the site.

CMP completed several additional response activities including placement of a chain link fence

around the Site in 1985, removing the above ground storage tanks in 1986, and extending the

chain link fence and removing over 500 tons of material from the scrap area in 1987.

Following completion of an RI/FS in 1989, the ROD was for the Site was issued on September

27, 1989. CMP, an identified Potentially Responsible Party (PRP) at the site, signed a Consent

Order with the USEPA on September 3, 1991 to undertake an investigation and remediation of

the site. CMP also acquired ownership of the Site from the F. O'Connor Co. in 1992.

3.5 Basis for Taking Action

The hazardous substances that have been released to the Site are primarily related to PCS oils

and scrap from the dismantling of transformers. Based on the compounds detected on the Site

during the Rl, contaminants of concern were identified. These contaminants of concern were

listed in Table 1 of the ROD, and are provided in the first column of Table 3-1 of this report.

As discussed in the ROD, an Endangerment Assessment was performed to estimate the

potential adverse human health and environmental effects from exposure to the contaminants of

concern. The major conclusions drawn from the Endangerment Assessment are as follows:

• Direct contact with, ingestion of, or inhalation of vapors from soils contaminated with

PCBs and carcinogenic polyaromatic hydrocarbons (cPAHs) may pose an incremental

increase in cancer risk over a lifetime of exposure. Children potentially playing on the

Site currently, or future residents living on the Site would be at the greatest risk. Lead in

soils may also pose a risk of adverse, non-carcinogenic health effects (through direct

contact and ingestion) by potential future residents living at the Site.

RI02942F 3-6 Tetra Tech NUS, Inc.
• An increased cancer risk over a lifetime of exposure may also be associated with direct

contact and ingestion by children with the PCB-contaminated sediments in the lagoons

located on the Site.

• Ingestion of the contaminated groundwater from the deep/bedrock system under the Site

may pose potential long-term risks to future inhabitants of the Site. Contaminants of

concern are 1,4-dichlorobenzene, benzene and PCBs.

• Environmental risks to biota (i.e., fish, wildlife and plants) exposed to contaminated soils,

sediments, or surface waters at the Site may potentially exist from the presence of

PCBs, lead and aluminum.

Based on the results of the Endangerment Assessment, Applicable or Relevant and Appropriate

Requirements (ARARs) and other guidance, target cleanup goals (see column 2 of Table 3-1)

were established to protect human health and the environment from these identified risks. The

ROD proposed a selected remedy for the Site that would meet these target cleanup goals.

RI02942F 3-7 Tetra Tech NUS, Inc.
TABLE 3-1

CONTAMINANTS OF CONCERN AT SITE

FIVE-YEAR REVIEW REPORT

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

Contaminants of Concern

 1

Soil

PCBs

CPAHs

Lead

Cadmium

Copper

Nickel

Zinc

Surface Water

PCBs

Lead

Aluminum

Groundwater

PCBs

Benzene

1 ,4-Dichlorobenzene

Bis 2-ethylhexylpthalate

Chromium

Manganese

On-Site Sediment

PCBs

CPAHs

Lead

Copper

Manganese

Zinc

Riggs Brook Sediment

PCBs

Riggs Brook Biota

PCBs

Target Cleanup Goal

 z

1 ppm

1 ppm

248 ppm

NA

NA

NA

NA

0.065 ppb

1.94ppb

87 ppb

0.5 ppb

5 ppb

27 ppb

NA

NA

NA

1 ppm

1 ppm

248 ppm

NA

NA

NA

1 ppm

NA

Selected Remedy

 3

1 ppm (DA=10ppm)3

1 ppm (DA=10ppm)3

248 ppm

NA

NA

NA

NA

0.065 ppb

1.94 ppb

87 ppb

0.5 ppb

5 ppb

27 ppb

NA

NA

NA

1 ppm (5 ppm4)

1 ppm

248 ppm

NA

NA

NA

1 ppm/5 ppm

 5

2 ppm6

Notes:

1. Based on Results of the Rl.

2. Based on results of Endangerment Assessment, ARARs, and other guidance.

3. Target cleanup goal for ROD (September 1989) Selected Remedy, and revised by ESD (Explanation of Significant

Differences (July 20, 1994)). DA = Designated Area.

4. OU-1 Area 3 soils near Riggs Brook wetland.

5. 1 ppm is the target cleanup goal; 5 ppm is the trigger level for performing additional sampling and determining whether

further remedial action is necessary. ROD pg. 47 and 52; Revised SOW (October 20, 1994), pg. 15.

6. ROD pg. 47 and Revised SOW pg. 15.

RI02942F 3-8 Tetra Tech NUS, Inc.
4.0 REMEDIAL ACTIONS

This section describes the remedial actions selected for and implemented at the Site.

4.1 Remedy Selection

The September 27, 1989 ROD for the Site determined that exposure to the contaminated media

at the Site may present an imminent and substantial endangerment to public health, welfare, or

the environment if the threats were not addressed by a response action. A remedy was

selected to meet the following response objectives identified for the Site:

• Reduce potential present and future public health and environmental risks from direct

contact, ingestion, and/or dermal absorption with the PCB-, cPAH-, and leadcontaminated soils and sediments located on- and off-site;

• Reduce potential present and future public health risks from the inhalation of PCB

vapors from the Site;

• Reduce potential present and future public health risks from the ingestion of PCBcontaminated fish from Riggs Brook;

• Reduce potential future public health risks from the ingestion of PCB-, benzene-, and 1,4

dichlorobenzene-contaminated groundwater found on the Site; and

• Reduce potential present and future environmental risks to aquatic and terrestrial wildlife

from exposures to the PCB-, lead-, and aluminum-contaminated on-site surface water.

The remedy selected in the ROD included components for Source Control and Management of

Migration.

4.1.1 Source Control

The Source Control (OU-1) component of the remedy included:

• Excavation and on-site treatment by solvent extraction technology of all soil and

sediment containing concentrations of PCBs and cPAHs greater than 1 ppm and lead

greater than 248 ppm;

• Draining and off-site treatment of all surface waters on the Site;

RI02942F 4-1 Tetra Tech NUS, Inc.
• Re-routing of existing surface water drainage patterns;

• Installation of erosion control measures and clearing of vegetation;

• Transportation and off-site disposal of soil and sediments should solvent extraction not

achieve target cleanup levels;

• Establishment of compensatory wetlands;

• Site restoration following excavation activities;

• Five-year review of site conditions.

On July 11, 1994 an ESD was approved and appended to the ROD. Based on an assessment

of the ability to implement the ROD remedy, the ESD adjusted the soil target cleanup goals for

all soils that would be located more than 12 inches below grade and within a three- to four-acre

Designated Area to a maximum 10 ppm PCBs and cPAHs and 248 ppm lead. The target

cleanup goals for soils outside the Designated Area remained at 1 ppm PCB and cPAH and 248

ppm lead (see Column 3 of Table 3-1). The ESD also provided for a contingency remedy that

allowed soils and sediments to be disposed off site without solvent extraction treatment,

pending USEPA approval. On October 23, 1995 USEPA invoked the contingency remedy,

based upon the determination that the solvent extraction treatment was not feasible to meet the

target cleanup goals.

4.1.2 Management of Migration

The MOM groundwater component (OU-2) of the ROD selected remedy required:

• Establishment of temporary institutional controls until groundwater remediation goals are

achieved;

• Installation of groundwater extraction and monitoring wells;

• Installation of an on-site groundwater treatment and recharge system;

• Treatment and recharge system monitoring, operation, and maintenance; and

• Five-year review of site conditions.

The MOM also included remedial actions for Riggs Brook sediment (OU-3). These included:

• Establishment and implementation of an extensive sediment and biota sampling and

analysis program within Riggs Brook;

RI02942F 4-2 Tetra Tech NUS, Inc.
• Implementation of public education programs; and

• Five-year review of site conditions.

A Revised Statement of Work (RSOW) was submitted on October 20, 1994 and appended the

Consent Decree. The RSOW defined the remaining work to be completed at the Site and

finalized the target cleanup goals for the MOM (see Table 3-1).

4.2 Remedy Implementation

Activities completed during the implementation of the remedies specified in the ROD are

described in this section.

4.2.1 Source Control (OU-1)

The SCRA, OU-1, was completed in two phases. Phase I was conducted in the summer and

fall of 1996 and included decontamination, demolition, and disposal of the barn and other nonnative debris, remediation of soils closest to Route 17; and construction of the support area for

Phase II activities. Phase II began in May 1997, and the SCRA was completed on

November 11, 1997. Phase II activities included collection and disposal of on-site surface

waters, sampling and remediation of soils and sediments in the former TWAs and the remainder

of OU-1, reconstruction of the Upper Lagoon, Lower Lagoon and the Upland Marsh and final

restoration of the Site. Institutional controls limiting access to the Site were included in the form

of a perimeter site fence.

Approximately 23,000 tons of soil and sediment were excavated and disposed off-site or

consolidated into the Designated Area (see Figure 4-1) to meet the target cleanup goals. As

listed in Table 3-1, the target cleanup goals for soil outside the Designated Area were 1 ppm

PCBs, 1 ppm cPAHs, and 248 ppm lead; and 1 ppm PCBs for on-Site sediments in the vicinity

of the Riggs Brook Wetland area. Target cleanup goals within the Designated Area were 10

ppm PCBs, 10 ppm cPAHs and 248 ppm lead. Soil and sediment samples were collected using

a sampling grid developed to provide a statistically valid approach for confirming that the

excavation had met the target cleanup goals. Additional random samples were collected as

determined necessary in the field to confirm attainment of target cleanup goals.

RI02942F 4-3 Tetra Tech NUS, Inc.
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Approximately 24,000 cubic yards of clean backfill (containing less than or equal to 1 ppm

PCBs, 1 ppm cPAHs and 248 ppm lead) were brought on-site for re-grading. The entire

Designated Area was covered with 12 inches of clean fill to ensure that, even if those soils

contaminated with between 1 and 10 ppm PCBs or cPAHs within the Designated Area were

ever disturbed by potential future activities at the Site, the PCB and cPAH levels at the surface

would likely be less than 1 ppm due to mixing with the clean soil. Excavated areas of the Site

outside of the Designated Area were backfilled and regraded. No additional cover was added in

the areas outside the Designated Area.

Site restoration included re-establishing drainage patterns to achieve discharges to Riggs Brook

similar to those that existed prior to remediation of the Site. It also included restoration of onsite wetlands and the establishment of approximately 0.4 acres of compensatory wetlands. The

SCRA was completed on November 11, 1997.

4.2.2 Management of Migration (OU-2)

Management of Migration remedial actions for groundwater are ongoing and include monitoring

groundwater to assess the potential for migration of contaminants from the Site. Investigations

completed following the ROD determined that the migration of contaminants in the shallow

groundwater in the downgradient direction is limited; the bedrock aquifer has low groundwater

storage and therefore a relatively small volume of water. It was also concluded that the 1992

pump test had mobilized oil and other contaminants vertically downward into the bedrock flow

regime. Based on these findings the RP contractor recommended continued groundwater

monitoring and the use of vacuum extraction rather than conventional groundwater pumping, to

eliminate the potential for drawing free floating product further into the bedrock aquifer (W&C,

2000).

Institutional controls were established in the form of a Declaration of Restrictive Covenant

signed by MEDEP and CMP. This covenant includes the following:

• Any use of the groundwater beneath the Site is prohibited without the written approval of

MEDEP;

• Any activity which might disrupt remedial or monitoring measures is prohibited without the

written approval of MEDEP; and

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• CMP or any subsequent owner shall maintain the Site in a condition adequate to ensure

the continued compliance with all applicable standards and to ensure the ongoing

adequacy of the remediation.

This Covenant has not been recorded and is currently held in escrow by MEDEP. A copy of the

covenant and a map showing the area covered by the covenant are included in Appendix E.

The formal MOM groundwater-monitoring program began in October 1995 using 15 of the Site

wells (7 overburden and 8 bedrock). A number of wells were removed during soil excavation;

new wells have also been added. The 16-well monitoring network now consists of 10

overburden and 6 bedrock wells. In addition to the MOM wells, five wells in the former TWA II

area are routinely checked for the presence of residual oil.

Seepage of oil into the TWA II wells has been observed since oil was first introduced into the

wells during the 1992 pump test. Approximately 29.8 gallons of oil was recovered from these

wells in October 1994. A VER system was applied to an overburden recovery well in the TWA II

area in 1996 and 1997, removing approximately 26.6 gallons of residual oil from the till/bedrock

interface. Following the completion of the SCRA in 1997, oil seepage into the wells decreased

significantly. Between the end of the SCRA and the summer of 2001, approximately 7.1 gallons

of oil was recovered from the wells. The VER Phase III was operated in the fall of 2001 and

removed approximately 19.8 gallons of oil. The total amount of oil recovered from the five

TWA II wells since their installation is approximately 85.2 gallons. (W&C, 2000; W&C 2001 d).

To date the MOM monitoring program (wells outside TWA II) has shown that the groundwater

meets the ROD target cleanup goals at the perimeter of the Site. Other groundwater monitoring

wells show decreasing trends for those compounds not yet at the cleanup standard. Within the

TWA II area, concentrations of PCBs, benzene, and 1,4-dichlorobenzene exceed the target

cleanup goals. The source of this contamination in groundwater in the TWA II area is believed

to be the residual oil trapped in the cracks in the clay and bedrock fractures. The TWA II area

wells are the subject of an application for a Technical Impracticability (Tl) waiver being sought

by CMP.

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4.2.3 Riggs Brook (OU-3)

The 10-year Riggs Brook sediment sampling and analysis program began in October 1996, and

has continued on an annual basis every fall. There have been sporadic exceedances of the 5

ppm trigger level for PCBs over time, and in accordance with the program described in the

ROD, in 1997 two hot-spot sediment areas were excavated. At EPA's request, the 2000 annual

program was supplemented with a sampling grid with 51 locations adjacent to Riggs Brook and

in Areas 2 and 3 of the former Source Control area of the Site. Four locations exceeded the

Riggs Brook trigger level for PCBs of 5 ppm. In addition, two locations in the former Source

Control Area 2 exceeded the Source Control target PCB level of 1 ppm. As of the fall 2001

sampling, concentrations of PCBs slightly exceeded the Riggs Brook trigger level at one

location.

Biota was sampled in 1997 following completion of the SCRA. The next biota sampling event,

scheduled for five years later, was instead completed in 2000 at the request of USEPA.

Concentrations of PCBs in biota were below the threshold level of 2 ppm in both sampling

events.

The ROD/RSOW required that CMP implement a public education program to increase public

awareness about the status of contamination within Riggs Brook. The status of Riggs Brook

was discussed as part of the Community Meetings and interaction leading up to and during

SCRA. Due to minimal interest expressed by the public regarding Riggs Brook or the Site since

the completion of SCRA, further meetings have not been held.

4.3 System Operations/O&M

An O&M plan for the Site calls for a 10-year post-closure monitoring period that will include

inspections, routine maintenance, and repairs as necessary. O&M activities for OU-1 include

inspections and wetland construction compliance monitoring. For OU-2, O&M activities cover

checking the integrity of the Site groundwater monitoring wells. Since OU-3 consists of

sediment and biota monitoring, there are no O&M activities.

Site inspections for OU-1 have been performed by CMP. CMP's inspections have reported that

vegetation is well developed, thicker in some areas than others, and that drainage channels are

in good condition and functioning as designed. Annual mowing has not been routinely

RI02942F 4-7 Tetra Tech NUS, Inc.
performed, as planned, in order to allow the vegetation to establish itself. However, access to

the wells and site access road has not been a problem. Minor erosion on the eastern slope of

the Site was repaired in May 1999. The only erosion noted since was some small rill erosion on

the western bank of the Lower Lagoon; the area was allowed to re-vegetate naturally. Minor

ruts in the access road were repaired in September 1999.

Compliance monitoring to evaluate wetland vegetation survival and general wetland system

recovery has been completed annually for three years following the completion of wetland

restoration in 1997. Monitoring will continue in years 5 (2002) and 10 (2007) to assess the

success of the wetland restoration and achievement of the goals established in the design

phase. The year 3 (2000) restoration report (Smart 2001) concluded that the Site had a postrestoration wetland acreage shortfall of approximately 0.2 acres in 2000. The report's

assessment of other goals of the project concluded the restoration has:

• maximized the percent of cover and the diversity of the plant community,

• established effective erosion control and stabilization measures,

• contributed to the availability of habitat in the surrounding community, and

• reestablished wetland function and values.

O&M costs for OU-1 include site inspections and site repairs. O&M costs were originally

estimated at approximately $15,000 for year 1 and $3,000 for years 2 through 10. According to

the RP contractor, costs have been lower than originally estimated in the O&M plan because the

Site has not been mowed and the only significant repair work was minor erosion and access

road repair conducted in 1999. O&M costs, provided by the RP contractor, are shown in Table

4-1. These costs do not include the semi-annual site inspections performed by CMP, CMP

labor costs, or the wetland construction monitoring performed by The Smart Associates. The

RP contractor plans to revise and submit the O&M Plan.

O&M costs for OU-2 have been limited to the costs of groundwater monitoring. No maintenance

has been required to date for the wells. According to the RP contractor, groundwater monitoring

costs are approximately $50,000 per year. Since there is no O&M associated with OU-3, there

are no associated O&M costs.

RI02942F 4-8 Tetra Tech NUS, Inc.
TABLE 4-1

ANNUAL SYSTEM OPERATIONS/O&M COSTS - OU-1

FIVE-YEAR REVIEW REPORT

O'CONNOR COMPANY SITE

AUGUSTA, MAINE

Dates

From

11/97

11/98

11/99

11/2000

To

11/98

11/99

11/2000

11/2001

Total Cost

$250

$1500

$250

$250

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5.0 PROGRESS SINCE LAST FIVE-YEAR REVIEW

This is the first Five-Year review for the Site.

RI02942F 5-1 Tetra Tech NUS, Inc.
6.0 FIVE-YEAR REVIEW PROCESS

6.1 Administrative Components

EPA, the lead agency for this five-year review, notified MEDEP and the RPs in early 2002 that

the five-year review would be completed. The RPs agreed to assist in preparing portions of the

required information. CMP's environmental consultant, Woodard & Curran, Inc., provided

USEPA with material for the review. This effort was conducted between January and April

2002. USEPA issued a scope of work to TtNUS, W.A. No. 123-FRFE-0133, under the USEPA

RAC1 contract 68-W6-0045, on March 1, 2002 to assist USEPA in performing the five-year

review. The USEPA Work Assignment Manager was Nancy Smith; support was provided by

Terrence Connelly, the USEPA Remedial Project Manager for the O'Connor Site. Wilkes

Harper and Hank Andolsek of the MEDEP were part of the review team. The Draft Five-Year

Review Report was provided to MEDEP for their review in early July. MEDEP transmitted

comments to EPA in a letter dated August 9, 2002 (see Appendix F).

The original schedule established by USEPA specified completion of the five-year review by

August 2002.

6.2 Community Notification and Involvement

EPA issued a press release on May 8, 2002 that was published in the Kennebec Journal

announcing EPA's review of the progress of the O'Connor Site cleanup. The press release

encouraged public participation. There is no established Community Advisory Group. To date

EPA, MEDEP and CMP have encountered little participation or involvement from the local

community. All site-related documents are available at the Lithgow Public Library in Augusta.

According to staff at the library there has been limited use of the documents.

6.3 Document Review

This five-year review consisted of a review of relevant documents including decision documents,

work plans, and various monitoring reports (See Appendix A).

RI02942F 6-1 Tetra Tech NUS, Inc.
6.4 Data Review

6.4.1 Source Control OU-1

Since the completion of the remedial action for the Source Control Operable Unit at the Site in

1997, semi-annual site inspections have been conducted by CMP to observe any physical

changes at the Site that would compromise the remedy. In addition, wetlands construction

monitoring was conducted annually for years 1, 2, and 3 following wetlands restoration in 1997,

and will be conducted in years 5 and 10. Inspection reports conclude that vegetation is well

developed, drainage channels are in good condition and functioning as designed. The most

recent wetland monitoring report concludes the overall Site is providing the interspersion of

wetland and upland communities for the recovery of available wildlife habitats (Smart, 2001).

The report also noted an approximately 0.2 acre shortfall in the post-restoration wetland area.

6.4.2 Management of Migration OU-2

Historic results of the MOM monitoring, excluding the five wells located in the TWA II area,

conducted between October 1995 and September 2001 and prior analytical results were

reviewed. Target cleanup levels have been set for RGBs (0.5 ug/L), benzene (5 ug/L) and 1,4-

dichlorobenzene (27 ug/L). There are no established cleanup standards for other VOCs in the

1989 ROD.

PCBs. Aside from a few initial sampling events (prior to 1994), concentrations of PCBs in

groundwater samples collected from wells outside of the TWA II Area have not exceeded the

ROD target cleanup level for PCBs (0.5 ug/L). The results of March 1999 groundwater analyses

using USEPA Modified Method 680 for total homologue PCBs showed total PCS and estimated

maximum possible concentrations ranging from 0.02 - 0.09 ug/L, well below the ROD target

cleanup level. (W&C, 1999)

VOCs. Concentrations of volatile organic compounds (VOCs) have been fluctuating and

generally decreasing, and are near target cleanup goals in wells outside the TWA II area. The

downward trend in VOC concentrations is most evident in the bedrock wells. The concentrations

in the overburden wells are generally low and near or below the target cleanup levels. The

benzene target (5 ug/L) has not been exceeded in any of the MOM wells, and has generally

RI02942F 6-2 TetraTechNUS, Inc.
been found to be below or close to the detection limit. Based on a review of the historical

groundwater monitoring data, the concentrations of 1,4- dichlorobenzene have fluctuated and

have frequently exceeded the target (27 ug/L) in three of the MOM wells (MW-104B, OW-201B,

and MW-507A). These wells are all located slightly downgradient of the TWA II area. These

exceedances are summarized below.

MW Number

MW-104B

OW-201B

MW-507A

Lowest Cone. TDate]

<2.5 ppb [3/26/97]

< 0.5 ppb [6/9/92]

< 0.5 ppb [3/29/00]

Highest Cone. [Date]

91 ppb [7/1 5/91]

56 ppb [12/9/97]

81 ppb [12/9/97]

Latest ConcJDate]

30 ppb [9/1 8/01]

28 ppb [9/1 7/01]

36 ppb [9/1 8/01]

The RP contractor reported in the MOM Sampling and Analysis Quarterly Report, September

2001 that a Mann Kendall trend test was performed that indicated a statistically significant

downward trend in the 1,4-dichlorobenzene concentrations in these wells (W&C 2001).

Well MW-106B flows under artesian conditions most of the year. As such, it provides an

indication of the water quality of the bedrock groundwater migrating from the Site. Low levels of

six VOC compounds are regularly detected at MW-106B and are reported to be generally

decreasing or staying at relatively constant low levels. The levels of benzene and 1,4

dichlorobenzene are below target limits (W&C, 2001 c).

Monitoring wells MW-507A and MW-508B were placed in the bedrock trough, which is the

primary discharge pathway for groundwater from the upper portions of the Site. The

concentrations of 1,4 dichlorobenzene have generally decreased below the ROD limit in

MW-507A, although this limit was exceeded in the sample obtained in September 2001 during a

period of drought. The bedrock concentrations of this compound observed in MW-508B are well

below the ROD limit. (W&C, 2001 c).

Groundwater monitoring using the existing 16 well monitoring network should continue on a

semi-annual basis to check for decreasing trends in 1,4-dichlorobenzene concentrations.

TWA II Wells. The groundwater from the five wells in the TWA II Area have typically not been

sampled because the oil in these wells would not give representative results of the dissolved

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concentrations. The limited number for samples collected for VOC and PCB analysis were

determined to not be representative of actual dissolved contaminants in the groundwater.

To date the MOM monitoring program (wells outside TWA II) has shown that groundwater

meets the target cleanup goals at the perimeter of the Site, and at other locations shows

decreasing trends for those compounds not yet at the target cleanup goal. Within the TWA II

area, concentrations of RGBs, benzene, and 1,4-dichlorobenzene exceed the target cleanup

goals. The source of this contamination in groundwater in the TWA II area is believed to be the

residual oil trapped in the cracks in the clay and bedrock fractures. The TWA II area wells are

the subject of an application for a Tl waiver being sought by CMP. Future monitoring in the

TWA II wells and surrounding area may change based on action taken on the Tl waiver request.

6.4.3 Riggs Brook OU-3

Sediment monitoring has been conducted annually at Riggs Brook since 1996, and biota

monitoring was conducted in 1997 and 2000. The six years of sediment sampling are

summarized below. PCB concentrations have exceeded the 5 ppm trigger level in a few

locations. PCB concentrations in biota have not exceeded the 2 ppm threshold level.

Year Results

1996 Concentrations of total PCBs were below the 5 ppm trigger level at all sediment

sample locations.

1997 PCB concentrations exceeded 5 ppm at two sediment sample locations (8004

and 8013). More rigorous sampling was conducted and the sediment was

remediated by excavating the two small hot spots.

1998 PCB concentrations exceeded 5 ppm at two sampling locations (8006 and 3018).

1999 PCB concentrations at sample location 8006 continued to exceed 5 ppm but were

lower than 1998 concentrations. The PCB concentration at sample location 3018

was below the trigger level in 1999.

2000 PCB concentrations at sample location 8006 continued to exceed 5 ppm but

decreased from 1999 concentrations. PCBs at sample location 3018 stayed

below the trigger level. USEPA requested that additional sediment samples be

collected in the area between the former Source Control area (OU-1) and Riggs

Brook. Of these additional samples, concentrations of PCBs exceeded the trigger

level of 5 ppm at four out of 51 locations.

2001 PCB concentrations at sample location 8006 dropped below the 1 ppm cleanup

level. PCBs at sample location 3018 were slightly above the trigger level (6.1J

ppm). The four additional locations where exceedances were observed in 2000

were sampled again in 2001, and the concentrations were below 5 ppm at all four

locations.

Source: W&C 2001 e

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The supplemental sampling grid established by USEPA in 2000 showed the four exceedances

of the Riggs Brook 5 ppm PCB trigger level mentioned in the table above, as well as two

exceedances of the Source Area 1 ppm PCB target level. The PCB concentrations were 1.4

and 3.8 ppm at the two Source Area 1 locations on the slope downgradient of the lower lagoon

(W&C, 2001 b). According to the RP contractor, these two locations have not been re-sampled

since 2000.

6.5 Site Inspection

A site inspection was conducted on May 22, 2002 with representatives from EPA, MEDEP,

CMP, EPA's contractor and CMP's contractor. The inspection included a site walkover focusing

on the Designated Area boundary and observations of the vegetated cover, monitoring wells,

restored wetland areas, the upland marsh and Riggs Brook area. The Site is no longer secured

with fencing and not all of the monitoring wells have secure locks. In 1997, the fence was

determined to be no longer necessary once the soil cover was placed over the Designated

Area, eliminating this exposure route. There has been no reported vandalism or trespassing on

the Site. The vegetation is well established, swales constructed to direct runoff from the

lagoons toward Riggs Brook are in good repair. The Site inspection report, including site

photos, is included in Appendix B.

CMP staff check the Site frequently and stated that while the Site is not routinely mowed,

mowing will be performed if required for access to wells and for ongoing operations. Since the

Site was farmland in the 1950's the perimeter trees and other vegetation have become wellestablished in areas where there were no active operations. Many birds were heard and seen

during the walkover.

No significant development of surrounding areas is underway; municipal water supply is

available. As noted in Section 3.2, zoning districts encompassing the Site permit residential

development. Institutional controls are covered in the Declaration of Restrictive Covenant

signed by MEDEP and CMP and held in escrow by MEDEP. CMP and the RP contractor

reported that there have been no known violations of the terms of the Covenant.

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6.6 Interviews

General discussions and observations were documented during the site inspection on May 22,

2002. Telephone interviews were conducted with other individuals. All individuals contacted

regarding the five-year review are shown in Appendix C.

Roy Koster, CMP, noted that CMP personnel visit the Site on a monthly basis and check the

wells in the TWA II area for floating oil. When present, oil is collected using absorbent pads

which are then taken to a CMP transfer facility in Augusta. CMP has no plans to develop the

site; it was noted that most of the development in Augusta is on the west side of the Kennebec

River.

Mr. Bill Bridgeo, Augusta City Manager, was contacted by telephone on June 3, 2002. He knew

of the Site and its location but stated that no concerns about the Site have been brought to his

attention over the past few years.

Mr. Horace Rodrigue was contacted by telephone on June 3, 2002. He stated that the parties

responsible for the cleanup of the Site did a "superb job." Mr. Rodrigue has observed all-terrain

vehicles using the Site. He owns property directly across Route 17 from the Site and attributes

his inability to sell it over the past 10 years to the property being across the street from a "dump"

site.

Current land use and flood zone maps were obtained from the Augusta City Services office.

Staff at the office were familiar with the location of the O'Connor Site but did not express any

concerns about the activities that have been completed. The administrative record and site

documents are available at the Lithgow Public Library in Augusta. Library staff indicated that

few individuals have accessed the documents.

To date USEPA has received no response from the public following publication of the press

release in May 2002.

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7.0 TECHNICAL ASSESSMENT

The following sections evaluate the remedy based on its function in accordance with decision

documents, its adherence to valid risk data and scenarios and any other information that could

have affected the remedy's protectiveness. ARARs and To Be Considered (TBC) guidance for

the Site identified during the development of the 1989 ROD along with current ARARs and

TBCs are provided in Appendix D of this Report for reference.

7.1 Question A: Is the Remedy Functioning as Intended by the Decision

Documents?

7.1.1 OU-1: Source Control Remedial Action

Remedial action performance and monitoring results. The information presented in the Final

Source Control Remedial Action Report (W&C, 1998) shows that the Site was remediated in

accordance with the requirements of the ROD (USEPA, 1989) as modified by the ESD (USEPA,

1994). The soil excavation and covering of the Designated Area with clean fill during the SCRA

reduced public health and environmental risks from direct contact with contaminated soils and

sediments, exposure to surface water, and reduced public health risk from inhalation of

contaminated vapors. The site inspections show that the integrity of the soil cover placed over

the Designated Area has been maintained and the Source Control remedy is functioning as

intended. EPA, MEDEP, and CMP are finalizing an O&M plan to ensure the long-term integrity

of the soil cover over the Designated Area. This plan will include the collection of shallow

subsurface samples coincident with future five-year reviews to assess whether there are PCBs

above the 1 ppm concentration in the soil cover.

Wetlands Construction Monitoring Reports completed by Smart Associates in 1998, 2000, and

2001 conclude that the Site is achieving project goals.

Operations and Maintenance Costs. Maintenance of the Site, including the gravel access road,

soil cover on the Designated Area, and the restored wetlands has been effective. As discussed

earlier in this report, minor erosion had occurred on the soil cover and the gravel road, and was

repaired. The minor erosion that did occur was not deep, and did not affect the protectiveness

of the remedy.

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O&M costs are less than originally estimated because site repairs have been minimal (see

Table 4-1). The O&M costs presented in Table 4-1 do not include the site inspections which are

performed by CMP or the wetland monitoring performed by Smart Associates.

Opportunities for Optimization. Three measures for optimizing maintenance of the SCRA are

suggested. First, it is proposed that on-site markers be installed to more clearly define the

Designated Area. This would enable personnel conducting site inspections to see the

boundaries of the Designated Area while walking around the Site.

Secondly, revision and agency approval of the O&M Plan to reflect current O&M practices is

suggested. This plan will include the collection of shallow subsurface samples coincident with

future five-year reviews to assess whether there are PCBs above the 1 ppm concentration in the

soil cover.

The third optimization suggestion is to reevaluate Site institutional controls currently covered by

the Declaration of Restrictive Covenant between the MEDEP and CMP. All parties, e.g.

USEPA, MEDEP and CMP, should agree with the form and duration of institutional controls for

the Site.

Indicators of Remedy Problems. Based on site inspections conducted, there do not appear to

be any indicators of remedy problems.

Implementation of Institutional Controls. The Declaration of Restrictive Covenant prohibits any

activity that might disrupt remedial or monitoring measures at the Site, or any use of the

groundwater beneath the property without prior written approval of the MEDEP. The

Declaration of Restrictive Covenant also requires that CMP maintain the property to ensure the

ongoing adequacy of the remediation implemented under the Consent Decree. The

implementation of institutional controls, even though the restrictive covenant is in escrow and is

therefore not legally enforceable, has thus far effectively ensured the integrity of the remedial

measures conducted at the Site, and has prevented exposure to Site soils. The Agreement,

Release and Stipulation and the Declaration of Restrictive Covenant are provided in

Appendix E. The RP contractor has reported that no activities have been observed on the Site

that would have violated the institutional controls.

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7.1.2 OU-2: Management of Migration

Remedial Action Performance and Monitoring Results. Review of relevant MOM documents

and results of the quarterly and semi-annual groundwater monitoring indicates that the MOM

remedy is functioning as intended except within the TWA II Area. As described earlier in this

report, concentrations of PCBs and VOCs either meet ROD target cleanup goals or are trending

downward, except in an upland area including and surrounding the TWA II Area. Although the

SCRA was successfully completed, small amounts of residual oil, containing PCBs and VOCs,

remain in fractures in the clay and to a limited extent in bedrock. However little movement of

residual oil has been observed.

Groundwater remediation with the VER system and monthly passive oil recovery has removed

approximately 85 gallons of residual oil from the TWA II wells since 1992, and about 27 gallons

of that since the completion of the SCRA in 1997. Groundwater monitoring results indicate

decreasing trends in concentrations of VOCs over the entire Site, including the TWA II Area.

Due to the fact that the remedy is not functioning as intended within the TWA II Area, a Tl

Evaluation Report supporting a Tl waiver for the TWA II area has been submitted to USEPA for

approval. This Tl Report proposes a groundwater remedy that would be protective of human

health and the environment and includes a request for a Tl waiver from specific ARARs within

an area established as the Tl Zone. The proposed Tl Zone encompasses the TWA II Area and

the area associated with shallow groundwater flow to the south of the TWA II Area. Monitoring

wells along the boundary of the proposed Tl Zone will be monitored to ensure that drinking

water standards are met outside of the proposed Tl Zone.

Operations and Maintenance/Costs. There have been no O&M costs for the MOM other than

the water quality monitoring. No maintenance has been required for the wells. Based on

information provided by the RP contractor, groundwater monitoring costs are approximately

$50,000 per year.

Opportunities for Optimization. The groundwater-monitoring network should be reevaluated and

the locations and number of wells included in the network modified based on agreement by

USEPA, MEDEP and CMP. It may be possible to reduce the number of wells routinely sampled

based on a review of historical groundwater results.

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The VER Phase III activities conducted in 2001 extracted approximately 19.8 gallons of oil from

the TWA II wells, and primarily from the bedrock wells. This was the first time a vacuum had

been applied directly to these wells. To determine if further amounts of oil can be extracted

from these wells, the VER should continue to be applied to the TWA II wells annually during a

period of low groundwater (probably later summer) and the recovery rate of oil tracked.

As previously stated, groundwater samples collected from observation wells in the TWA II Area

are not representative of the actual dissolved contaminants in the groundwater. This is due to

an oil emulsion that is often observed in these wells. Therefore, it is proposed that these wells

continue to be observed for oil, but that they not be added to the MOM program at this time.

Indicators of Remedy Problems. As stated above, the indicator that the remedy is not

functioning as intended in the TWA II Area is the residual oil observed in cracks in the clay that

continues to be a source of PCBs and VOCs in groundwater at concentrations that exceed their

respective cleanup levels. Groundwater in the TWA II area is the subject of an application for a

Tl waiver being sought by CMP. The application for a Tl waiver is included in a Tl Evaluation

Report that has been submitted to USEPA for approval.

Implementation of Institutional Controls. The implementation of institutional controls, through the

Declaration of Restrictive Covenant, has thus far prevented exposure to contaminated

groundwater at the Site. A reevaluation of the form and duration of institutional controls by

USEPA, MEDEP and CMP is suggested to ensure the integrity of the remedial measures

conducted at the Site.

7.1.3 OU-3: Riggs Brook

Remedial Action Performance and Monitoring Results. Review of documents related to, and

sampling data obtained from, Riggs Brook sediment and biota, indicates that subsequent to

PCB hot spot removal in 1997 the remedy is functioning as intended by the ROD and RSOW.

Sediment sampling and analysis has been conducted annually since 1996, and biota sampling

and analysis was conducted in 1997 and 2000.

Over the last six years PCB concentrations in sediment have exceeded the ROD cleanup goal

of 1 ppm and sporadically exceeded the ROD 5 ppm trigger level in several locations. The

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Mann-Kendall statistical trend analysis does not show any statistically significant trends. In

2001 there was one sediment sample location where PCBs exceeded 5 ppm (6.1 ppm), and

one other location that exceeded 1 ppm. All the remaining sediment samples contained less

than 1 ppm of PCBs. Continued monitoring has shown that over time the PCB concentrations

have continued to decrease, and in most cases the concentrations have decreased until they

are below the cleanup goal.

The results of the 1997 and 2000 biota sampling events have shown that PCB concentrations

have not exceeded 2 ppm (the ROD threshold limit). According to the 2000 Sediment and Biota

Monitoring Report, the small amount of PCBs detected in Riggs Brook sediment does not

appear to be impacting biota since the PCB concentrations in biota from the 1997 and 2000

sampling events have remained consistent or slightly decreased (W&C 2001 b). Although not

found to be statistically significant, decreasing concentrations of PCBs have been found at most

of the sediment sampling locations. Additionally, since the exceedances of the sediment trigger

level do not appear to be impacting the biota, the remedy is functioning as intended.

Operations and Maintenance Costs. Since the remedial action for OU-3 is monitoring, there are

no other operations or maintenance occurring at Riggs Brook. The costs of the hot spot

remediation that was conducted in 1997 were included with the Source Control activities and

have not been separately tracked. Based on information from the RP contractor, annual costs

for Riggs Brook sediment sampling and analysis are approximately $20,000.

Opportunities for Optimization. The possibility of decreasing the sampling locations has been

discussed. However, given the transient nature of sediments, USEPA has decided to continue

with the same monitoring program for the duration of the ROD-specified period (until 2006).

Indicators of Remedy Problems. Based on annual sediment and biota monitoring, there do not

appear to be any indicators of remedy problems. Although PCBs have been detected each year

in one or more sediment samples, the concentrations are only slightly exceeding the trigger

level of 5 ppm at a few locations and overall concentrations of PCBs appear to be decreasing.

In addition, concentrations of PCBs in sediment do not appear to be impacting biota (all

samples less than the threshold level of 2 ppm).

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Implementation of Institutional Controls. Institutional controls for the Site, described in OU-1,

also apply to OU-3.

7.2 Question B: Are The Exposure Assumptions. Toxicitv Data. Cleanup

Levels and Remedial Action Objectives (RAOs) Used at the Time of

Remedy Selection Still Valid?

7.2.1 OU-1: Source Control Remedial Action

Changes in Standards and TBCs. As a part of this five-year review, the ARARs presented in the

ROD have been reviewed, and a review of current ARARs has been conducted. Due to the fact

that SCRA has been completed, most ARARs for soil contamination cited in the ROD have

been met.

There are no current chemical-specific ARARs that apply to soil contaminants at the Site. TBC

guidance that was written following the 1989 ROD includes the 1990 USEPA Guidance on

Remedial Actions for Superfund Sites with PCB Contamination, the 1994 USEPA Revised

Interim Soil Lead Guidance for CERCLA Sites and RCRA Corrective Action Facilities, and the

1997 MEDEP Remedial Action Guidelines (RAGs). The USEPA Guidance on Remedial Actions

for Superfund Sites with PCB Contamination recommends soil action levels of 1 ppm for sites in

residential areas and 10-25 ppm for sites in industrial areas. The USEPA Revised Interim Soil

Lead Guidance recommends 400 ppm for lead in soils. The MEDEP RAGs for PCBs range

from 2.2 to 8.1 ppm for residential, trespasser and adult worker guidelines. Benzo(a)pyrene is

used as an indicator contaminant for cPAHs, and the RAGs range from 2 to 9 ppm. For lead,

the RAGs range from 375 to 700 ppm.

These more recent guidance are less conservative than the ROD target cleanup goals of 1 ppm

PCBs, 1 ppm cPAHs and 248 ppm lead used to remediate the areas of the Site outside the

Designated Area. Although the target cleanup goals inside the Designated Area were 10 ppm

PCBs, 10 ppm cPAHs and 248 ppm lead, the top 12 inches of soil on the Designated Area has

concentrations of PCBs less than 1 ppm. Therefore, additional guidance written after the 1989

ROD does not affect the protectiveness of the SCRA completed at OU-1.

Changes in Exposure Pathways. Seven exposure scenarios were identified in the

Endangerment Assessment (Clement, 1988), including three potential current exposures and

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four potential future exposures. These exposures include contact by trespassers, recreational

fishing, and potential future residential exposures. Land use at the Site has not changed and is

not expected to change, and there are no additional routes of exposure.

Changes in Toxicity and Other Contaminant Characteristics. Although toxicity factors have

changed for some of the chemicals, the cancer slope factors (CSFs) (formerly called cancer

potency factors) have, in general, decreased. A decrease in a cancer slope factor indicates that

potential risk from exposure to contaminants is lower than previously calculated. The

contaminants with the greatest cancer risk potential at the Site were PCBs and cPAHs. CSFs

for PCBs have been changed from 7.0 (mg/kg/day)"1 to 7.7 (mg/kg/day)"1. Considering the

concentrations of PCBs that are being detected on site, it is unlikely that this small change could

adversely affect the protectiveness of the remedy. In addition, risk values for cPAHs, as

evaluated by using benzo(a)pyrene, have been decreased, with the current oral CSF of 7.3

(mg/kg/day)"1 lower than the 1988 value of 11.5 (mg/kg/day)"1. Therefore, the changes in toxicity

of these compounds would not affect the outcome of the Endangerment Assessment because

there is no notable change in the risk of cancer at the Site.

There have also been changes made to the Risk Reference Doses (RfDs) since the

Endangerment Assessment. These values are used to quantify the risk associated with specific

contaminants. The alterations made to the RfDs used to determine risk for this Site would not

affect the protectiveness of the remedy. Of the seven contaminants for which RfDs were listed

in 1988, three have not changed, two have increased slightly and one decreased by an order of

magnitude. None of these were contaminants of concern in the ROD. Risk associated with noncarcinogenic PAHs was not calculated in the assessment. RfDs are now available for many of

those compounds. Based on the low cleanup levels for the cPAHs and PCBs (which would

potentially be co-located with the non-carcinogenic PAHs), cleanup of the non-carcinogenic

PAHs is expected to have occurred during remediation.

Changes in Risk Assessment Methods. The only changes in risk assessment methods since

the RI/FS are the manner in which lead is evaluated, the way in which risk to constituents in air

is estimated, and the use of certain exposure estimates. None of these changes affect the

protectiveness of the remedy.

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Currently, lead exposures to children are modeled using the Integrated Exposure Uptake

Biokinetic Model (IEUBK), available from USEPA. Federal standards for lead are currently set

at 400 mg/kg for residential use, based on this model. Because the cleanup level established

for lead in soil was 248 mg/kg, the cleanup goal is protective of potential future use of the Site.

The methods used to assess risk to constituents in air have changed. In addition, some of the

default exposure assumptions have changed, specifically for dermal exposure, based on studies

reviewed by USEPA. While these changes would have slight effects on calculated risks, there

is no potential for exposure as long as the soil cover over the Designated Area is maintained

and therefore the soils with less than 10 ppm PCBs are not accessible. The target cleanup

goals set in the ROD remain protective of the exposures and receptors identified for the Site.

Expected Progress Towards Meeting RAOs. The SCRA was completed and met the remedial

action goals for OU-1.

7.2.2 OU-2: Management of Migration

Changes in Standards and TBCs. The primary change to the ARARs list for groundwater is the

addition of the 1992 Maine Maximum Exposure Guidelines (MEGs). The effect of this ARAR is

the addition of five VOCs to the list of compounds in Site groundwater that have promulgated

cleanup standards. There are also MCLs for three of these VOCs; however, their values are the

same or higher than their respective MEGs. In addition, the 1992 MEG of 0.05 ppb PCBs is

significantly lower than the 1989 ROD target cleanup goal of 0.5 ppb for PCBs. These MEGs

were revised in 2000, and the MEG for PCBs was once again changed to 0.5 ppb, but these

revisions have not been promulgated. According to the MEDEP, the 1992 MEGs are referenced

in the Maine hazardous waste regulations, are enforceable and are therefore applicable to this

Site. Therefore, for the purpose of this five-year review, the 1992 MEG for PCBs of 0.05 ppb is

the applicable ARAR for groundwater. When the groundwater cleanup target goal for this Site

was set at 0.5 ppb, the current MCLs and Maine MEGs were taken into consideration. Since

these MEGs have become more strict since the ROD was issued, it may be necessary in the

future to recalculate risk based on these new standards to ensure the protectiveness of the

remedy.

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Changes in Exposure Pathways. Although institutional controls are in place at the Site, and

there are no plans to develop the Site for residential or commercial use, future residential use is

protective of other receptors, including potential commercial workers and temporary

construction workers. One pathway excluded from the Endangerment Assessment was

exposure to volatiles in indoor air originating from shallow groundwater. A review of current

groundwater data was conducted to determine whether this route of exposure is complete. In

the areas of the Site that could be redeveloped (i.e., on more even terrain), shallow groundwater

is primarily at a depth of 10 to 20 feet below ground surface. Concentrations of two VOCs, 1,2-

dichlorobenzene (ranging from 9 to 93 ug/L) and 1,4-dichlorobenzene (ranging from 4 to 36

ug/L), have only slightly exceeded the ROD target cleanup goal and MEGs (27 ug/L and 85

ug/L, respectively), at one well (507A) in the shallow aquifer during the 2001 sampling. These

concentrations are not expected to adversely impact indoor air in potential future buildings.

Bedrock groundwater was not evaluated for this pathway, as shallow groundwater is the

potential source for volatilization into indoor air. Based on the limited concentrations in shallow

groundwater, the exposure pathways that were evaluated remain valid.

Changes in Toxicitv and Other Contaminant Characteristics. As discussed for OU-1, although

toxicity factors for some chemicals have changed, in general, the CSFs have decreased. The

oral CSF for 1,4-dichlorobenzene, PCBs and benzene are 2.4 E-2 (mg/kg/d)"1, 7.7 (mg/kg/d)"1

and 2.90 E-2 (mg/kg/d)"1, respectively. The oral RfD (for non-cancer outcomes) for PCBs is

2.00E-5 (mg/kg/d)"1. The RfD for benzene and 1,4-dichlorobenzene were not assessed under

the EPA's Integrated Risk Information System (IRIS). The inhalation toxicity factor for

1,4-dichlorobenzene is 8.0 E-1 mg/m3. This value was not in the original assessment, nor was it

published for benzene or PCBs in IRIS. For all three of these contaminants, the CSFs

referenced in the Endangerment Assessment have since been changed, however only PCBs

now have a higher CSF. Only one of the above contaminants has been detected in groundwater

outside the Designated Area, and the target cleanup goal for 1,4-dichlorobenzene is lower than

the MEG. Additionally, the concentrations in the shallow groundwater are below or very close to

the MEG. Review of this information indicates that the remedy remains protective.

Changes in Risk Assessment Methods. Since the target cleanup levels for groundwater were

based on MCLs and MEGs, changes in risk assessment methods would be accounted for

because MCLs and MEGs use conservative default assumptions and are updated periodically.

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Expected Progress Towards Meeting RAOs. A Tl waiver has been requested for a portion of

the Site groundwater, referred to as the Tl Zone (including and surrounding the TWA II Area),

where concentrations of VOCs (e.g., benzene, 1,4-dichlorobenzene) and PCBs exceed the

ROD target cleanup goals and current ARARs. USEPA has indicated the Tl waiver will be part

of a ROD amendment that is expected to be signed in September 2002. In the past 14 MOM

sampling events, neither benzene nor PCBs have been detected in wells downgradient of

TWA II. Additionally, the concentrations of 1,4-dichlorobenzene show a statistically significant

downward trend.

7.2.3 OU-3: Riggs Brook

Changes in Standards and TBCs. Guidance for sediment written after 1989 include sediment

quality criteria published by the National Oceanic and Atmospheric Administration (NOAA), the

Ontario Canada Ministry of Energy, USEPA and Oak Ridge National Laboratory. These criteria

are included in Appendix D as TBCs. Although these sediment criteria are more conservative

than the ROD target cleanup goal of 1 ppm, at the time of the ROD, the USEPA, U.S. Fish and

Wildlife Service and NOAA agreed that the potential for irreversible environmental damage

caused by sediment excavation to achieve the cleanup goal of 1 ppm outweighed the

disadvantages of leaving contaminated sediments in place. Therefore, the ROD set a trigger

level of 5 ppm which, if exceeded, would require more rigorous sampling to determine the need,

if any, for further remedial action.

Changes in Exposure Pathways. Land use in the Riggs Brook area has not changed and is not

expected to change, and there are no additional routes of exposure.

Changes in Toxicity and Other Contaminant Characteristics. The major contaminant that has

been historically detected in Riggs Brook sediments is PCBs. The current cancer slope factor

for this contaminant is 7.7 (mg/kg/d)"1. The original cancer slope factors for PCBs referenced in

the Endangerment Assessment was 7.0 (mg/kg/d)"1. Although this is a slight increase in the

cancer risk posed by exposure to PCBs, monitoring is on-going in Riggs Brook, and overall

concentrations of PCBs seem to be decreasing.

Changes in Risk Assessment Methods. Since the ROD was written in 1989, there have been

some changes to the risk assessment methods for sediments. The major change involved

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dermal exposure assumptions. However, since Riggs Brook is rarely used for recreation, and

since the levels of contaminants detected in sediments are fairly low and the exposure

assumptions made in the Endangerment Assessment were conservative, the remedy still

remains protective.

Expected Progress Towards Meeting RAO. There have been periodic exceedances of the

5 ppm trigger level for RGBs in Riggs Brook sediment since sampling began in 1996.

Supplemental sampling was undertaken to determine the extent of sediment with these higher

levels. The extent of the exceedances was found to be very limited. In 2001, concentrations of

PCBs slightly exceeded the target level at one location, and were less than 1 ppm at all

remaining locations. Concentrations of PCBs in biota were below the target level of 2 ppm in

both the 1997 and 2000 sampling events.

7.3 Question C: Has Any Other Information Come To Light That Could Call Into

Question The Protectiveness Of The Remedy?

7.3.1 OU-1: Source Control Remedial Action

The OU-1 SCRA was completed with the covering of the Designated Area where soils with less

than 10 ppm PCBs were consolidated, and the subsequent reestablishment of vegetation.

Therefore, Site soils are not accessible so there is no potential for exposure. Since no new

ecological targets were identified during the five-year review, the monitoring of ecological

targets is not necessary. No other information has been discovered that would call into question

the protectiveness of the remedy.

7.3.2 OU-2: Management of Migration

The main issue in OU-2 is the Tl Waiver being sought for the Designated Area. Currently,

concentrations of Site contaminants exceed both ROD target clean-up goals and current

ARARs. However, since a Tl Waiver is currently being sought to provide reprieve from these

standards, at the time of this five-year review the protectiveness of the MOM remedy should not

be called into question. No other information has been discovered that would call into question

the protectiveness of the remedy.

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7.3.3 OU-3: Riggs Brook

The remedy selected for Riggs Brook consisted of the monitoring of contaminants in sediments.

There have been exceedances of clean-up goals for OU-3; however, ecological risks have been

adequately addressed and there is on-going biota monitoring scheduled for Riggs Brook. While

this area is mapped as a Zone A flood hazard area, it has not been affected by any flooding or

other weather-related events and no other information has been discovered that would call into

question the protectiveness of the remedy.

7.4 Technical Assessment Summary

According to the data reviewed, the site inspection, and the interviews, the remedy is

functioning as intended by the ROD, as modified by the ESD. There have been minor changes

to the physical conditions of the site, caused by erosion, but these changes do not affect the

protectiveness of the remedy. Most ARARs for soil, groundwater or sediment contamination

have been met. There have been some changes in toxicity factors, most notably the increase in

the CSF for RGBs, but the changes have not been significant enough to effect the original

determination of risk in the ROD. Additionally, there have been no changes to the standardized

risk assessment methodology that could affect the protectiveness of the remedy. Finally, there

is no other information for any of the OUs that calls into question the protectiveness of the

remedy.

7.4.1 OU-1: Source Control Remedial Action

The SCRA was completed in accordance with the ROD through the excavation and offsite

disposal of soil and sediment with greater than 10 ppm PCBs, and the consolidation and

covering of soil with less than 10 ppm PCBs into the Designated Area. Additionally, O&M costs

have remained lower than original estimates. Most ARARs that apply to soil on Site have been

met pursuant to the ROD, and additional TBCs identified since the ROD have also been met.

Land use at the Site has not changed over the years, nor it is expected to in the future, therefore

all exposure pathways identified remain valid, and no new pathways have emerged. Although

some toxicity values for contaminants on Site have changed, the change would not impact the

outcome of the original Endangerment Assessment since there would be no significant change

RI02942F 7-12 Tetra Tech NUS, Inc.
in cancer risks at the Site. With the completion of the SCRA, the remedial action goals for OU-1

were met.

7.4.2 OU-2: Management of Migration

As described in previous sections, documents and sampling results for the MOM portion of the

Site show that the remedy is functioning as intended, with the exception of the TWA II Area

where PCBs and VOCs exceed their cleanup limits. There have been no additional O&M costs

beyond the original scope of work. The Declaration of Restrictive Covenant, that is being held

in escrow by the MEDEP, prevents exposure to contaminated Site groundwater. The one

significant change in standards affecting the status of OU-2 is the change in the MEG for PCBs.

This change decreased the MEG by one order of magnitude, therefore making it more

conservative than the Site clean-up goal established in the ROD.

One new potential exposure pathway identified since the ROD is the indoor pathway that would

exist if buildings were constructed on-site. However, there are currently no plans for any on-site

construction and all previously identified pathways remain valid.

There were some changes in toxicity data for Site contaminants, however only the CSF for

PCBs indicates a slightly greater risk of cancer than previously determined. Since the change is

insignificant, the original assessment remains valid.

7.4.3 OU-3: Riggs Brook

Document and data reviews for Riggs Brook indicate that the remedy is functioning as intended

by the ROD and RSOW. The institutional controls implemented for the rest of the Site also

apply to OU-3. During the most recent round of sediment sampling conducted in 2001,

concentrations of PCBs slightly exceeded the trigger level, reaching 6.1 ppm at one location,

and were less than the 1 ppm target cleanup goal at all remaining locations. Concentrations of

PCBs in biota were below the threshold level of 2 ppm in both the 1997 and 2000 sampling

events.

There are several TBC documents that were reviewed for this report that provide guidance in

establishing sediment standards. Although there have been exceedances of the 5 ppm trigger

RI02942F 7-13 Tetra Tech NUS, Inc.
level, it was determined by the EPA, the U.S. Fish and Wildlife Service and NOAA that leaving

contaminated sediments in place would cause less harm to the ecosystem than performing an

excavation. As with the other OUs, the change in the CSF for PCBs would slightly alter the risk

values for sediments, however not enough to alter the protectiveness of the remedy.

RI02942F 7-14 Tetra Tech NUS, Inc.
8.0 ISSUES

As discussed previously, the groundwater in the TWA II area of the Site is being impacted by

residual oil and is not achieving the groundwater cleanup goals. A request for a Tl waiver is

currently under review by the EPA and MEDEP. Therefore, the OU-2 remedy as currently

constituted is not protective. Groundwater in other portions of the Site is showing decreasing

trends in target cleanup levels.

While there may be opportunities to optimize OU-1 O&M activities and OU-3 annual sampling

activities, the remedies are currently protective and are expected to continue to be protective in

the future.

The Riggs Brook sediments do not consistently meet the target cleanup goal. The annual

sediment-monitoring program is planned to continue until 2006. As part of the five-year review

process, MEDEP has expressed concerns that the target cleanup goal of 1 ppm for the Riggs

Brook sediment set in the 1989 ROD may not adequately address ecological risk. MEDEP also

now disagrees with the statement that sediment excavation would cause irreversible damage to

the Riggs Brook wetlands.

The change in ARARs for OU2, specifically the promulgation of the 1992 MEG for PCBs is an

issue that should be addressed. The 1992 MEG (0.05 ppb) is significantly lower than the 1989

ROD target clean-up goal of 0.5 ppb for PCBs. Although it may not affect the overall

protectiveness of the remedy, the 1992 MEGs for PCBs remain enforceable. Therefore a

reevaluation of the OU-2 target level for PCBs in groundwater is warranted. The reevaluation

would serve as an assurance that the cleanup goal for PCBs remains protective of human

health and the environment.

Two locations in the Source Control area included in the 2000 sediment sampling grid exceeded

the 1 ppm PCB cleanup level. Since this portion of the Site was not covered with 12 inches of

clean soil, these locations should be resampled during the 2002 Riggs Brook sediment

monitoring event to assess the potential for exposure.

There is presently no agency-approved O&M Plan. An updated Plan is being prepared by CMP.

RI02942F 8-1 Tetra Tech NUS, Inc.
The 0.2-acre shortfall in post-restoration wetland area is an issue that will be closely monitored

during the years 5 and 10 events. This does not affect the current protectiveness of the

remedy.

Restrictions on groundwater use at the Site should be reevaluated as a result of the Tl waiver.

RI02942F 8-2 Tetra Tech NUS, Inc.
9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS

The approval of the PRP's Tl Waiver will result in revision the ARARs for OU-2 and a

modification of the remedy via a ROD amendment. This process is currently underway by

USEPA with the support of MEDEP. This and other issues and actions required are

summarized in the table below.

Issue

OU-2 Cleanup

goals not

achievable in

TWA II area

PCB MEG

(0.05 ppb)

SC sample

exceedance of

1 ppm PCB

level

O&M Plan

Shortfall in

restored

wetland area

Restrictions

on future

groundwater

use

Recommendations/

Follow-up Actions

Implement necessary

regulatory changes to

the remedy for OU-2

Analyze groundwater

at lower DL to

determine if remedy

meets the PCB MEG

Resample the two

locations from the

2000 EPA grid

Update O&M Plan,

obtain agency

approval

Regulatory oversight of

yearS and 10 events

Reevaluate the

Institutional Controls

and restructure to

reflect current Site

conditions

Party

Responsible

EPA

CMP

CMP

CMP

CMP

EPA/State

Oversight

Agency

State

State/EPA

State/EPA

State/EPA

State/EPA

CMP

Milestone

Date

September

2002

September

2002

Fall 2002

Summer

2002

2007

September

2002

Affects

Protectiveness?

(Y/N)

Current

Y

N

N

N

N

Y

Future

Y

N

N

N

N

Y

RI02942F 9-1 Tetra Tech NUS, Inc.
10.0 PROTECTIVENESS STATEMENTS

OU-1: The remedial action for OU-1 has been completed and is protective of human health and

the environment. Exposure pathways that could result in unacceptable risk are being controlled.

The finalization of the O&M plan will ensure that the OU-1 remedy will remain protective.

OU-2 : The remedy at OU-2 is not protective in the TWA II area of the Site and surroundings

defined as the Tl Zone in the Tl Waiver due to the presence of residual oil in the subsurface and

PCB and VOC concentrations that can not meet target cleanup levels. Actions now underway

to implement the Tl Waiver are needed to ensure protectiveness.

OU-3 : The remedy at OU-3 is expected to be protective of human health and the environment

upon completion of the 10-year sampling program. In the interim, exposure pathways that could

result in unacceptable risks are being monitored. The annual sediment monitoring, which began

in 1996, has found periodic and isolated exceedances above the 5 ppm trigger level. Additional

sampling and hot spot excavation in 1997 indicated that the exceedances are limited areally and

over time. The biota sampling has indicated that the remedy for OU-3 is protective of human

health, and with the anticipated continued decrease in dissolved PCB concentrations in the

discharging groundwater, the remedy is expected to remain protective of human health.

RI02942F 10-1 Tetra Tech NUS, Inc.
11.0 NEXT REVIEW

A second five-year review for the O'Connor Site will be conducted in 2007.

RI02942F 11-1 Tetra Tech NUS, Inc.
APPENDIX A

DOCUMENT REVIEW LIST/REFERENCES
DOCUMENTS REVIEWED/REFERENCES CITED

City of Augusta, ME, Land Use Ordinance.

Flood Insurance Rate Map, City of Augusta, Maine, Kennebec County, Community-Panel

Number 230067 0011 C. June 15, 1994.

ICF - Clement, Inc., 1988. Endangerment Assessment for the O'Connor Site in Augusta,

Maine.

The Smart Associates, 2000. 1999 Wetland Construction Monitoring Report, O'Connor

Company Site, Augusta, Maine; August 15, 2000.

The Smart Associates, 2001. 2000 Wetland Construction Monitoring Report, O'Connor

Company Site, Augusta, Maine; March 13, 2001.

USEPA, 1989. Record of Decision Summary, U.S. Environmental Protection Agency, Region 1,

Boston, Massachusetts, September 1989.

USEPA, 1990. Guidance on Remedial Actions for Superfund Sites with PCB Contamination,

OSWER Directive No. 9355.4-01. August 1990.

USEPA, 1991. "Consent Decree - United States of America, Plaintiff v. Central Maine Power

Company, Defendant." Septembers, 1991.

USEPA, 1994. Declaration for the Explanation of Significant Differences, O'Connor Company

Superfund Site, Augusta, Maine, July 11, 1994.

USEPA, 1995. Invocation of Contingency Remedy, O'Connor Company Superfund Site,

Augusta, Maine, October 10, 1995.

USEPA, 2001. Comprehensive Five-Year Review Guidance, OSWER Directive 9355.7-03B-P.

June 2001.

US Fish & Wildlife Service, 2001. Comments on The Smart Associates, 2000 Wetlands

Construction Monitoring Report. June 29, 2001.

Woodard & Curran, 1996. Source Control Remedial Action Community Relations Plan,

Woodard & Curran, Inc., July 1996.

Woodard & Curran, 1997. Data Collection and Interpretation of the Phase II Operation of the

Vacuum Enhanced Recovery (VER) System at the O'Connor Site in Augusta, Maine,

Woodard & Curran Inc., June 27, 1997.

Woodard & Curran, 1999. MOM Sampling and Analysis Quarterly Report, March 1999,

O'Connor Company Superfund Site, Augusta, Maine, June 8, 1999.

Woodard & Curran, 2000. Draft Request for Technical Impracticability Waiver for OU-2

Management of Migration, O'Connor Company Superfund Site, Augusta, Maine, April 2000.
Woodard & Curran, 2001 a. Revised Long-Term Groundwater Quality Monitoring Program and

Phase III VER Work Plan, O'Connor Company Superfund Site, Augusta, Maine, July 25,

2001.

Woodard & Curran, 2001 b. 2000 Riggs Brook Sediment and Biota Monitoring Report, O'Connor

Company Superfund Site, Augusta, Maine, July 2001.

Woodard & Curran, 2001 c. MOM Sampling and Analysis Quarterly Report, O'Connor Company

Superfund Site, Augusta, Maine, October 26, 2001.

Woodard & Curran, 2001 d. Draft VER Phase III Report, O'Connor Company Superfund Site,

Central Maine Power Company, Augusta, Maine December 2001.

Woodard & Curran, 2001 e. 2007 Riggs Brook Sediment Monitoring Report, O'Connor

Company Superfund Site, Augusta, Maine, December 2001.

Woodard & Curran, 2002. Draft O'Connor Superfund Site Five-Year Review Document. April

2002.
APPENDIX B

SITE INSPECTION REPORT
O'Connor Company Site Inspection - May 22, 2002

Five Year Review, WA# 123-FRFE-0133

Attendees:

Nancy Smith - EPA WAM

Terry Connelly - EPA RPM

Wilkes Harper - MEDEP, Project Manager

HankAndolsek-MEDEP, Geologist

Phoebe Call - TtNUS, EPA Contractor, Project Manager

Katie Lang - TtNUS, EPA Contractor, Project Scientist

Roy Koster - Central Maine Power, Senior Environmental Specialist

John Carroll - Central Maine Power, Community Relations Specialist

Lori Moreau - Woodard & Curran - RP Contractor

The Site Inspection commenced at approximately 9:10 AM and concluded approximately 11:30

AM. Weather was sunny, approximately 60 degrees. Observations made by the EPA

contractor and other participants are noted below. Follow up interviews with site inspection

participants will be made at a later date.

Field Notes:

The Site is no longer secured with fencing. The fence was removed from the active treatment

areas after the clean fill cover was placed over the excavated areas and seeding was

completed.

The dirt access road is in good repair. The Site appears as well vegetated rolling hills, with an

upland marsh and two downgradient restored wetland areas. The Site is unattended.

No signage was observed either identifying the Site or restricting access.

The vegetation is well established; mowing has generally not been required.

Monitoring wells were easy to locate since they have high stickups. Mowing might be required

in the summer months to ensure access to wells as required for ongoing monitoring activities.

No records are retained at the Site. There is no treatment equipment, piping, etc. remaining at

the Site.

There has been no documented vandalism or trespassing on the Site, either before or after the

perimeter fence was in place.

The remaining monitoring wells are not all secured with well locks.

The Year 5 wetland restoration monitoring event will take place this year.

CMP personnel check the Site and the wells in the TWA II area for floating oil on a monthly

basis. Oil is collected with absorbent pads, which are taken off site to a CMP transfer facility in

Augusta. No hazardous materials are stored on the Site.
The oil remaining in the TWA II area is in a very tight clay formation. Last year the vacuumenhanced recovery (VER) operation recovered 20 gallons of oil. CMP personnel stated that 17

gallons were recovered from the bedrock and 3 gallons from shallow wells.

The RP contractor noted that due to the geology of the area there is no overburden aquifer. In

some areas that were excavated to a depth of 12 feet during source control groundwater was

not encountered. Due to the clays perched groundwater exists.

The pending Tl waiver and ROD amendment for OU2 was discussed at length. Issues as to the

boundaries of the 'designated area', area covered by the Tl waiver, etc. have yet to be settled.

The waiver will acknowledge that the groundwater in that area (once boundaries are set) can

not be cleaned up as originally envisioned, but efforts will likely continue using VER as long as

the process continues to remove oil.

CMP personnel noted that old aerial photos showed the area as open fields. It is thought that

the current open areas of the Site existed during site operations and woods became established

in undisturbed areas of the site. No trees were removed during the remedial activities at the

Site.

When the two lagoons were dewatered and remediated, a swale was constructed to guide

overland flow from the lagoons down the steep slope toward the wetlands surrounding Riggs

Brook. The reconstructed lagoon embankments and swales were in good repair.

New development in Augusta is on the west side of the Kennebec River. The Site is on the east

side and there has been no new development along Route 17 in the area of the Site since

remedial activities began. The only new structure observed was a home on top of a nearby hill

recently constructed on land formerly owned by CMP east of Riggs Brook.

During the source control excavations some monitoring wells had to be decommissioned.

The Superfund Site boundary is the same as the boundary in the Restrictive Covenant between

CMP and MEDEP. This area encompasses 23 acres; the 'designated area' is about 3 acres. A

Restrictive Covenant has been signed by both parties and is being held by MEDEP. This

document provides institutional controls limiting groundwater use while active remediation is

underway.

Sampling of biota and sediment in Riggs Brook has shown PCB contaminant concentrations in

fish and frogs below the standards. There have been a few sediment hot spots containing PCB

concentrations just over the applicable standard identified during the annual sediment sampling.

The Site was regraded to match the original contours as closely as possible. The soil cover is

well vegetated. There were no areas of erosion noted.

CMP personnel perform site inspections twice annually and document their observations.

There were many birds observed, especially in the wetland areas. A garter snake was found on

the slope between the former upper and lower lagoons.

O&M costs have been provided by the RP contractor as part of their information for the five-year

review.
The remedies as currently implemented are effective and functioning as designed. As noted

above the TWA II area is the subject of a Tl waiver request from CMP. Post source control RA

activities continue, groundwater monitoring continues on a semi-annual basis. Oil in wells in the

TWA II area is removed on a monthly basis when evident. VER will likely continue as long as it

is effective in removing additional oil.

AUGUSTA MUNICIPAL OFFICES - CITY SERVICES DEPARTMENT

Obtained flood plain maps and zoning maps for the area of the Site.

The clerk knew of the Site and its location but was not familiar with details.

LITHGOW PUBLIC LIBRARY

Personnel at the library confirmed that the O'Connor Site documents are in the basement of the

library. Individuals have accessed them in the past, but not have not done so recently.
O'CONNOR SITE INSPECTION

PHOTOGRAPHIC RECORD

Photo No.: 1

Date: 5/22/02

Comments: At the high point of the

Site at the TWA III area, on the road,

looking toward Route 17.

Photo No.: 2

Date: 5/22/02

Comments: Toward the wetland area

west of the access road.

Originals in color.
O'CONNOR SITE INSPECTION

PHOTOGRAPHIC RECORD

Photo No.: 3

Date: 5/22/02

Comments: From the TWA n area

toward the lower lagoon.

Photo No.: 4

Date: 5/22/02

Comments: From the lower lagoon

area looking toward Riggs Brook and

its wetlands.

Originals in color.
O'CONNOR SITE INSPECTION

PHOTOGRAPHIC RECORD

Photo No.: 5

Date: 5/22/02

Comments: Standing on the concrete

damn at the end of the upper lagoon

looking east toward the lower lagoon

and Riggs Brook.

Photo No.: 6

Date: 5/22/02

Comments: At the top of the swale

with back to the upper lagoon.

Originals in color,
O'CONNOR SITE INSPECTION

PHOTOGRAPHIC RECORD

Photo No.: 7

Date: 5/22/02

Comments: Upland wet area

Photo No.: 8

Date: 5/22/02

Comments: Upper lagoon/wetland

Originals in color.
O'CONNOR SITE INSPECTION

PHOTOGRAPHIC RECORD

Photo No.: 9

Date: 5/22/02

Comments: On Route 17 end of

access road facing uphill.

Originals in color.
APPENDIX C

SITE INTERVIEW LIST
INDIVIDUALS INTERVIEWED FOR THE O'CONNOR FIVE-YEAR REVIEW

Name/Position

William Bridgeo/ City

Manager

John Carroll/

Community Relations

Specialist

Wilkes Harper/Project

Manager

Roy Koster/Senior

Environmental

Specialist

Steve Mierzykowski/

Biologist

Lori Moreau/PRP

contractor

Horace Rodrigue/

neighbor

Cornell Rosiu

Organization/Location

City of Augusta, ME

Central Maine Power/Augusta, ME

Maine DEP/Augusta, ME

Central Maine Power/Augusta, ME

US Fish & Wildlife Service/Old Town, ME

Woodard & Curran./Portland, ME

Cony Road, Augusta, ME

USEPA/Boston, MA

Date*

June 3, 2002

May 22, 2002

&

May 29, 2002

May 22, 2002

& June 10,

2002

May 22, 2002

June 19, 2002

May 22, 2002

& May 29,

2002

June 3, 2002

June 20, 2002

* May 22, 2002 interviews were conducted during the site inspection; all other

interviews were conducted via telephone.

RI02942F Tetra Tech NUS, Inc
APPENDIX D

ARARS AND TBCS

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APPENDIX E

DECLARATION OF RESTRICTIVE COVENANT AND MAP SHOWING AREA COVERED BY

COVENANT
AGREEMENT. RELEASF AND STTPTn ATTON

This Agreement, Release and Stipulation is entered among the State of Maine and

Maine Department of Environmental Protection (collectively called "Department") and

Central Maine Power Company, Inc. ("CMP"), for the purposes of resolving claims by the

Department against CMP arising from conditions on a parcel of real property, more

particularly, described in the attached Declaration of Restrictive Covenant, which parcel

CMP owns and which parcel the Department has designated as an "uncontrolled

hazardous substance site" pursuant to 38 M.R.S.A. §§ 1364 - 1365, and attaching conditions

to said parcel of real property.

For purposes of this Agreement, and not to be construed as an admission by any

party, but subject to the conditions and limitations set forth below, CMP and the

Department hereby agree and stipulate as follows:

1. CMP is record owner of two parcels of property located on Eastern Avenue,

so-called (State Route 17) in Augusta, Kennebec County, Maine. Said parcels are more

particularly described in the-attached Declaration of Restrictive Covenant A portion of

the aforesaid parcels has been designated by the Department as an uncontrolled hazardous

substance site pursuant to 38 M.R.S.A. §§ 1364 and 1365 due to the presence in the soils on

the Site and the groundwatef under the Site of PCBs, polyaromatic hydrocarbons (PAHs), .

and lead, all of which are hazardous substances under Maine and Federal law. This same

portion has been listed on the National Priorities List as a "Superfund Site" by the United

States Environmental Protection Agency ("EPA"). The designated portion shall

hereinafter be referred to as the "Site".

2. As a generator of the lead, PCBs and PAHs who arranged to dispose of these

hazardous substances at the Site, CMP has been identified as one of the parties liable to

remediate the Site by both-the Department and EPA.

3. The Site is being cleaned up under a Consent Decree agreed to by CMP and

EPA on November 23,1990, which was entered by the United States District .Court for the

District of Maine on September 3,1991, at United States^ et si. v. Central M?me Power

Company; Civil Action No. 92-0302-B. Pursuant to this Consent Decree, CMP will

remediate the contaminated soils and surface water on the Site and contaminated

groundwater under the Site using methods approved by the EPA, after opportunity for

review and comment by the Department. The treatment technologies and cleanup levels

for lead, PCBs and cPAHs at the Site are set forth in me Record of Decision ("ROD") issued

by EPA. EPA proposes to adjust certain cleanup levels in a document identified as the

Explanation of Significant Difference (ESD).

•*! • '' ' \ : ; .• _ .. ..

4. The ROD states that on-site soils will be treated using solvent extraction, so as

to reduce the level of PCBs and cPAHs to one part per million (ppm).

5. While it is feasible to readvthls cleanup level for PCBs in the less

contaminated soils on site, information which came to light after the ROD was initially
•2-

acproved indicates that it will neither be technically feasible nor cost effective to achieve

the one ppm cleanup level using the specified solvent extraction method for the more

contaminated soils. In addition, EPA has determined that levels of 10 ppm of total PCBs

and 10-ppm of total cPAHs falls within the risk range which is protective of human health.

For these reasons, the soil cleanup levels set forth in the ROD wUl be adjusted by-EPA by

use of the ESD, such that the soil treatment method set forth in the ROD will be used only

on soils with contaminant levels greater than 10 ppm. and will terminate when the

residual .levels of the PCBs and cPAHs are lowered to 10 ppm. In order to protect the

environment, however, on-site soils containing levels of total PCBs and total cPAHs of

between 1 ppm and 10 ppm will be covered with clean soil" from off site sources, to the

thickness of 12. inches as specified in the ESD. The Department agrees that a soil cover 12

inches or greater meets the Department's risk criteria of 10^ provided that the cover is .

maintained.

6. Pursuant to the Consent Decree, following Site inspection and submission of

a written report signed by the CMFs Project Coordinator, and a registered professional

engineer, certifying .that all remedial activities have been completed in .full satisfaction of

the requirements of the Consent Decree, and EPA's agreement with this finding, EPA will

certify completion of the remedial work.

7. Natural resources of the State of Maine, including the groundwater tinder the

Site, have been damaged by contamination at the Site.

8. Under both:Section 107 of CERCLA, 42 U.S.C § 9607, and Maine's.

Uncontrolled Sites Law, 38 M.RS.A. § 1367 (1989), the State of Maine has a cause of action

against CMP for damages for-injury to, destruction of or loss of natural resources of the

State.

9. Use of the groundwater beneath the Site prior to the completion of

" remediation activities could pose risks to the public health and 'imperil the timely

remediation of the Site. Likewise, other on-site activities could disrupt remedial or

monitoring measures installed, pursuant to the Consent Decree or imperil the ongoing

adequacy of the remediation implemented under the Consent Decree, including, without

limitation, the dean soil cap described above. In order to avoid the possibility of any such

interferences, it is necessary for CMP to file a Declaration of Restrictive Covenant in the

form attached hereto as Exhibit 'A.

NOW, THEREFORE,

A. The effective date of this Agreement shall be the date upon which EPA issues

the ESD.

B. Within thirty (30) days of the effective date of this Agreement, CMP shall pa>

the sum of One Hundred Twenty-Five Thousand Dollars (5125,000.00) in full
-3-

cotnpensation for the natural resource damages described above. Payment shall be made

by a check made payable to the "Maine DEP Uncontrolled Hazardous Substance Fund."

This check shall be delivered within the time specified to the Director, Division of Site

Investigation and Remediation, Bureau of Hazardous Materials and Solid Waste Control,

State House Station #17, Augusta, Maine 04333:

C Within thirty (30) days of the effective date of this Agreement, CMP shall

date, execute and deliver to the Department for its acknowledgement, a Declaration of

Restrictive Covenant in the form attached hereto as Exhibit A. The Department shall

acknowledge and execute the Declaration and hold the Declaration in escrow until the

"completion of the remedial action" by CMP as that phase is defined and used in the

above-referenced Consent Decree. The Department shall then file the executed

Declaration in the Kennebec County Registry of Deeds.

In consideration of CMP's full and timely compliance with the terms of this

Agreement, and in consideration of CMP's full and timely compliance with all terms and

provisions of the Consent Decree it entered with the United States Environmental

Protection Agency, as described above, the Department releases and discharges CMP, its

principals, successors, assigns, parent corporations, subsidiaries, affiliates, agents, servantr

employees, attorneys and directors from all actions, suits, causes of action*'claims and

demands whatsoever, which the Department now has/or, but for the execution of this

Agreement, could or might have, against CMP, by reason of or in respect to the

contamination of the Site described in and addressed by the Consent Decree.

CMP releases the Department and the State of Maine from any and all actions, suits,

causes of action, claims or demands whatsoever which it might have, or but for the

execution of this Agreement, could or might have had, against the Department and the

State of Maine by reason or in respect to the contamination of the Site described in arid

addressed by the Consent Decree.

This Release shall become final and effective upon full payment of the amount

stated in paragraph A above, the filing of the Declaration of Restrictive Covenant provided

in paragraph B above and CMP's full and timely compliance with the Consent Decree,

including, without limitation, EPA's issuance of all certificates of completion called for by

the Consent Decree.

This Release does not apply to any person or entity not a signatory hereto and does

not apply to any conditions other than those described above.

By entering this Agreement, the Department does not waive and specifically

reserves all of its authority to address any conditions other than those described above

which may be discovered at the Site and may require additional work, •
DECLARATION OF RESTRICTIVE COVENANT

THE STATE OF MAINE )

, ) KNOW ALL MEN BY THESE PRESENTS THATCOUNTY OF KENNEBEC ) .

WHEREAS, Central Maine Power Company, a Maine corporation ("CMP"), is

record owner of two parcels of property located on Eastern Avenue, so-called (State

Route 17) in Augusta, Kennebec County, Maine. .Parcel #1 is described in a Deed

from William R- O'Connor to the. F. O'Connor Company, dated April 1,1977 and

recorded in the Kennebec-County Registry of Deeds in Book 1987, Page 44. Parcel #2

is described in a Deed from Carroll E. Theriault and Mary J. Theriault to Robert,!.

Hussey and Jean C. Hussey, dated August 31,1973 and recorded in the Kennebec' •

County Registry of Deeds in Book 1670, Page 165; and

• WHEREAS, a portion of the aforesaid parcels has been designated as an

Uncontrolled Hazardous Substance Site pursuant to 38 MJIS.A. §§1364 and 1365 by

the Maine Department of Environmental Protection ("DEP") and has been listed on

the National Priorities List as a "Superfund Site" by the United States

Environmental Protection Agency ("EPA") and is subject to remediation pursuant

to a Consent Decree entered between CMP and EPA; and

WHEREAS, an Agreement, Release and Stipulation entered into by CMP and

DEP requires CMP to file a Declaration of Restrictive Covenant in the Kennebec

County Registry of Deeds in order to ensure the integrity of certain remedial

measures;

NOW, THEREFORE, the parties hereto agree that the following covenant.

shall run with the land and be binding upon CMP and its successors and assigns,

and shall apply to the portion of the CMP parcels described in Attachment A, which

is attached hereto and made a part hereof, and which affected portion shall

hereinafter be referred to as the "Property" and shall be effective upon the

"completion of the remedial action" by CMP as that phrase is defined and used in

the above-referenced Consent Decree:

1. Any use of the groundwater beneath the Property shall be prohibited without

the prior written approval of me DEP.

2. Any activity which might disrupt remedial or monitoring measures installed

pursuant to the Consent Decree shall be prohibited without the prior written,

approval of the DEP.

3. . CMP or subsequent owner shall maintain the Property in a condition

adequate to ensure the-conturued compliance, with Tdl applicable cleanup

standards prescribed in, and to ensure the ongoing adequacy of the
.39

-2-

remediation implemented under the Consent Decree. By way of example,

and not by way of limitation, CMP or subsequent owner shall maintain all

drainage ways, berms, monitoring wells, permeable or impervious caps or

covers (including paved portions of the property and areas covered by topsoil

or other clean.fill), piping, pumps and electrical equipment constructed or

installed under the Consent Decree.

4. The parties hereto agree that the restrictive covenant herein shall be

perpetually binding upon the Property, however, if conditions on the

Property change, CMP or any subsequent owner of the Property may petition

DEP for consent to the removal of the restriction on the Property createdhereby and the termination of this Declaration of Restrictive Covenant.

5. The restriction contained herein shall only inure to the benefit of and shall

only be enforceable by DEP. No owner of any property or other third parry

shall benefit from the restriction contained herein or have any right or

standing to enforce same.

6. By its execution hereof, DEP acknowledges and agrees mat it has reviewed

and approved of the 'matters contained herein and that this Declaration of

Restrictive Covenant/ upon being filed in the Kennebec County Registry of

Deeds, will satisfy the applicable provisions of the Agreement, Release and

Stipulation it has entered with CMP regarding the Property.

IN WITNESS WHEREOF, the parties hereto have executed this Declaration of

Restrictive Covenant as of the - day of , 1994.

CENTRAL MAINE POWER COMPANY

By:

Name:

Title:

STATE OF MAINE ' - '

KENNEBEC, ss.

Personally appeared before me this day of April, 1994, the above-named

and made oath that the foregoing is true and

correct and based upon his/her personal knowledge.

NOTARY PUBLIC
D. E. P. flUGUSTfl ?3T

-3-

ACKNOWLEDGED AND

DEPARTMENT OF ENVIRONMENTAL

PROTECTION

Name: .

Title:

STATE OF MAINE . '

KENNEBEC, ss.

Personally appeared before me tius day of April, 1994, the above-named

and made oath that the foregoing is true and correct

and based upon his/her personal knowledge.

NOTARY PUBLIC
In addition, this is without prejudice to the Department's right with respect to all

matters not described above, including but not limited to, the following:

(1) Claims based on a failure by CMP to meet a requirement of this Agreement;

(2) State law claims arising from a failure by CMP to meet a requirement of the

Consent Decree;

(3) Liability for any future uncompensated response costs which the Department

may incur with regard to the Site. It is not presently contemplated that there

will be any such response costs, it being contemplated that the United States

Environmental Protection Agency's annual operations grant to the State of

Maine shall coverall State oversight costs incurred at the Site prior to the

issuance of certificates of completion by the EPA under the Consent Decree.

Notwithstanding any other provision of this Agreement, Release and Stipulation, the

Department retains all authority and reserves all rights to take any and all response actions

authorized by law and to seek reimbursements from CMP of costs incurred by the State in

taking such response actions.

DEPARTMENT OF ENVIRONMENTAL

PROTECTION

DATED:

ALAN M. PRYSUNkA

Director, Bureau of Hazardous

Materials & Solid Waste Control

STATE OF MAINE

KENNEBEC, ss.

Personally appeared before me this JJ *&& day of June, 1994 the above-named Alan M.

Prysunka, and made oath that the foregoing ia true and correct and based upon his personal

knowledge.

NOTARY PUBLIC
u= is 3.E.P.

T32S P.37

-OMAINE POWER COMPANY

Gerald C. Poulin

Vice President, Generation and

Technical Support

STATE OF MAINE

KENNEBEC, ss.

" DATED: June 8, 1994

andbased upon his personal taiowiedge.

a r..

NOT/iRY PUBUC

KARLAESVUASEY

Notary Public. Main*

My Cornminien Expire* April 1.2001
ATTACH: SENT 2

'•" • DEED DESCRIPTION

The following described parcel, situated on the Northeasterly side

of State Route 17, locally known as Eastern Avenue, in the city of

Augusta, Kennebec County, particularly bounded and described as

follows:

Beginning at a l" iron pipe found at an angle point in the

Northeasterly sideline of Eastern Avenue (Bk-4089-p. 269), as

shown on a plan entitled, "Standard Boundary Survey for

Central Maine Power Company, F. O'Connor Superfund Site" by

Coffin Engineering, Revision dated March 22, 1994. Said point

of beginning is also situated S 47"24'45" E of and 52.78 fee€

from a 3/4" iron pipe found at the most Southerly corner of

Henry R. & Lillian W. Cox (Bk 1554-p. 126) .

Thence N 47042'O3" E a distance of 623.68 feet to a 5/8" rebar

set in a stone wall in the Southwesterly line of Lionel J. &

Raymond A. Rodrigue (Bk 2857-p. 34). Said rebar is also

situated S 60°26'23" E of and 251.05 feet from a 5/8" rebar

set- in a drill hole at the most Easterly corner of Donald S.

Rodrigue (Bk 4164-p. 336) .

Thence Southeasterly along the Southwesterly line of Ridrigue,

and partially following said stone wall, to a 5/8" rebar set

at the Northwesterly sideline of a 100 foot wide transmission

line corridor designated Section #19 (Bk 1117-p. 314) . The

tie line between the two last mentioned rebars is S 6O°46'07"

E and 1,354.72 feet.

Thence S 35°12"18""W along the Northwesterly line of said

transmission corridor, a distance of 386.82 feet to a 5/8"

rebar set.

Thence S 79°45I02" W along the Northerly line "_of said

transmission corridor, a distance of 824.70 feet to a 5/8"

rebar set in the Northeasterly sideline of Eastern Avenue.

Thence N 40°50'03" W along the Northeasterly side of Eastern

Avenue, a distance of 822.31 feet to a 5/8" rebar set at the

most Southerly corner of land conveyed from Jean E. & Robert

L. Hussey to Central Maine Power Company (Bk 3507-p. 195).

Thence continuing N 40°50'03" along the Northeasterly side of

Eastern Avenue, a distance of 109.00 feet back to the point of

beginning.

Meaning and intending to describe 23.36 acres of land, as

shown on a plan "entitled, "Standard Boundary Survey for
Excepting the old Field burial ground which contains about one

eighth of an acre.

» - s s

X:\LHR\DEEOOES.CRN
i • !«.

00 J3MOd 3UIBH IBJ1U30

to putj
APPENDIX F

MEDEP COMMENTS, DATED AUGUST 9, 2002, ON THE DRAFT FIVE-YEAR REVIEW

REPORT
09/06/02 14:40 [3 :02/08 NO:882

S I ATE Ol: MAJNL

DlPAltlMINl ^1^ KlMVUtHNMCN I Al

ANGUS 3 KING Jfl MARTHA KIRKPATWCK

August 9, 2002

Terry Connelly

US Environmental Protection Agency

ME/VT/CT Superfund SectionUSEPA

1 Congress Street

Suite 11 00 HBT

Boston, MA 02114

RE: Draft Five Year Review Report

O'Conner Junkyard Superfund Site

Augusta, Maine

Dear Terry,

The Maine Department of Environmental Protection (MEDEP) has now completed its

review of the document entitled DRAFT Five Year Review Report (Report) for the

O'Conner Company Site (O'Conner Junkyard Site, or Site), dated July 2002 as prepared

by Tetra Tech NUS, Inc. for the Environmental Protection Agency (USEPA). MEDEP

offers the following comments on this Report

Executive Summary:

1 . Section 1 should contain a brief summary of the selected remedy, with emphasis

on the components of the remedy that involved leaving hazardous substances

behind and subsequent need for a 5 year review. As written it appears

premature to read about the soil cover and the Designated Area (In Section 3.1 )

before any discussion of site operations, responses, or remedies are presented.

2. Page E-1 , Paragraph 2 and Paragraph 3: Here and throughout the Report

mention is made of institutional controls protecting the public health by

preventing exposure to ground water, etc. This is incorrect. The Restrictive

Covenant is currently held in by MEDEP in escrow - it has not been

Implemented, nor was it intended to be until the remedy was deemed complete

by both MEDEP and USEPA.

3. Page E-2, First Bullet and page E-4, First Paragraph: That exposure pathways

are being controlled may be a bit misleading in that the restrictive covenants are

17 S-IATI" Housn yfATiors nANiJini POKILAN D I'HFKQUB isi r

AtKMJSTA. MAINF 04.HI. 11017 I0f. IIOC'AN «'1AI> »l I I'ANC O RI.IAI1 iJUCENIRAl PKlVIJ. SKYWAY PARK.

(107) ln'1-lttm IIANOOK. MAIN*. 04JH1 PORILANO, MAINP 0410) I'lM'SljUH ISIF, MAINE 1147AV-10W4

HAY 111 PC.. llnSPM Al ST. UO7> »<I-417|1 PAX Ul><) «4M<H4 I2O7I fUj.r,«00 TAX llVTl Hlt-l'tOt U07) 704-0477 I-AX: (2H7) 764-HD7

wrh file: vwo.iil.uv.mr.iii/iUp prln«tl on rcrvcUJ paper
09/06/02 14:40 |3 :03/08 NO:882

not Implemented yet and as of this writing CMP has no plan in place to maintain

the cover over the Designated Area.

Report

1. Page 1 -2 states that the triggering actions for this 5 year review are the August

1996 SCRA and the October 1994 actions for OU-2 and OU-3. Therefore,

technically, the 5 year review is overdue. Some explanation for this is needed for

the public record - at the very least an acknowledgement of this situation is

warranted.

2. Page 2-1, Table 2-1: The chronology presented in Section 2 should include the

agreement between DEP and CMP since this agreement established the

restrictive covenant and its enforceability that, once implemented, will provide a

measure of control over the exposure pathways that the Report keeps referring

to as already being in place.

3. Page 3-1, Section 3.1.1 • MEDEP does not understand the significance of

identifying the "small residence" that abuts the Site along the western boundary.

The important thing Is that land use on the western side is presently residential.

The actual size of that particular residence is irrelevant.

4. Page Section 3.1.3, 4lh sentence: There is a grammatical error - replace the

word "was" with the word "were:" (i.e. Approximately 24,000 cubic yards...were

imported...."

5. Page 3-3, Section 3.1.3, Paragraph 2: The Report mentions TWA I and III

without any prior definition or reference to what the acronyms mean. This makes

It difficult for the reader.

6. Page 3-3, Section 3.2: The text states that the site is not actively used.

Does this refer to CMP business activities, children playing on site, recreation

vehicles, or other site visitors? Please explain what this means

7. Table 3-1: Please explain further the apparent changes in cleanup levels; in

particular the change for PCBs in Riggs Brook sediments from 1 ppm to 5 ppm.

MEDEP is not aware of this value having undergone the official process for

change from the 1 ppm as originally established in the ROD. When was this

changed proposed for public comment? To MEDEP's knowledge neither

regulatory agency officially approved of such a change. Rather, the official,

enforceable cleanup level is still 1 ppm while 5 ppm is considered a sort of

unofficial trigger level for remedial action.

8. Page 4-3, Section 4.2.1, First Paragraph: The text states that "Institutional

controls limiting access to the Site were included in the form of a perimeter Site

fence." At the time of the ROD, the regulatory agencies incorrectly referred to

fences as institutional controls. Please update the text.

9. Figure 4-1: The document would benefit from a clearer site sketch than Figure

4-1. Since the TWA II area is so significant it should be clearly depicted. Also,
09/06/02 14:40 0 :04/08 N0:882

the first 4 symbols identifying the various types of monitoring wells/locations are

Identical. A color version of this figure where the first 4 symbols are differentiated

by hue would be more helpful, or if the figure is to remain black and white then

contrasting symbols are necessary.

10. Page 4-5, Section 4.2.2: The text mentions the establishment of institutional

controls, but fails to explain or specify what they are. Please add a summary.

11. Page 4-6, Section 4.2.3, First Paragraph: The text again incorrectly refers to a

5 ppm cleanup level for PCBs in Riggs Brook sediments. See comment #7 and

correct the text here and elsewhere in the Report.

12. Page 6-3, Section 6.4.2, Third Paragraph: The text Incorrectly states that

monitoring well 106B captures a significant portion of the bedrock groundwater

migrating from the site. This is not supported by any data, or even basic

hydrogeological principles. Well 106B only "sees" groundwater flowing through

its screen - it in no way actively captures adjacent groundwater. A pressure

gradient would have to be introduced through the well for it to do what is alleged

here. Delete the entire second sentence.

13. Page 6-4, Section 6.4.3, Results Box: Sediment cleanup level for PCB is not 5

ppm - it is 1 ppm. See comment #7.

14. Page 6-5, Section 6.5. First Paragraph: The text incorrectly refers to fences

and well locks are institutional controls, which they are not. Further, it claims well

locks were not necessary once the vegetated cap was installed. Please explain

how the cover negates the need for securing a monitoring well. In the Interim, all

wells should be secured with locks, especially considering the following: The site

ia Intentionally not secured - in fact the removal of the fence was made into a

media event with regulatory and CMP dignitaries present - so it is misleading to

report that trespassing was not observed.

15. Page 6-5, Section 6.5, Third Paragraph: A residence was recently built

adjacent to the site on the east side across Riggs Brook. Others may be

forthcoming. Therefore, claims that no development of the surrounding area are

underway are misleading. Also, the institutional controls are once again

mentioned in the text without any explanation as to what they actually are.

16. Page 7-1, Section 7.1.1; The text declares that the 12 inches of fill would be

protective even If the designated area was churned up and the clean soil and

PCB contaminated soil were mixed (page 4-5, First Paragraph). However, the

text in this section then refers to inspections of the cap to check for erosion and

placing boundary markers to identify the edges of the Designated Area. This is

confusing - the report should clarify what EPA's remedy is with respect to the

Designated Area. Further, it is impossible to verify the intergrity of the soil cover

in the absence of a marker liner placed underneath without sampling. Lastly,

there is no mention of MEDEP's independent agreement, independent authority,

and enforceable requirement for maintaining the 12 inches of clean fill over the

Designated Area.