SDMS DocID 278335

Second Five-Year Review Report

for

F. O'Connor Site

Augusta

Kennebec County, Maine

September 2007

PREPARED BY:

US Environmental Protection Agency

Region 1

Boston

Approved by:

V— Director Date (^Pames T. Owens, III, Dir

Office of Site Remediation and Restoration

U.S. Environmental Protection Agency - New England

TABLE OF CONTENTS

SECTION PAGE NUMBER

EXECUTIVE SUMMARY vi

1. INTRODUCTION 1

2. SITE CHRONOLOGY 2

3. BACKGROUND 4

3.1 Physical Characteristics 43.1.1 Setting 43.1.2 Topography 43.1.3 Subsurface Conditions 43.2 Land and Resource Use 53.3 History of Contamination 53.4 Initial Response 63.5 Basis for Taking Action 6

4. REMEDIAL ACTIONS 9

4.1 Remedy Selection 94.1.1 Source Control 94.1.2 Management of Migration 104.2 Remedy Implementation 124.2.1 Source Control (OU-1) 124.2.2 Management of Migration (OU-2) 134.2.3 Riggs Brook (OU-3) 154.3 System Operations/O&M 15

5. PROGRESS SINCE LAST FIVE-YEAR REVIEW 17

6. FIVE-YEAR REVIEW PROCESS 19

6.1 Administrative Components 196.2 Community Involvement 196.3 Document Review 196.4 Data Review 196.4.1 Source Control OU-1 196.4.2 Management of Migration OU-2 206.4.3 Riggs Brook OU-3 226.5 Site Inspection 246.6 Interviews 25

7. TECHNICAL ASSESSMENT 26

7.1 Question A: Is the remedy functioning as intended by the decision documents? 267.1.1 OU 1: Source Control Remedial Action 267.1.2 OU2: Management of Migration 277.1.3 OU 3: Riggs Brook 287.2 Question B: Are the exposure assumptions, toxicity data, cleanup levels and

remedial action objectives (RAOs) used at the time of remedy selection still valid? 29

7.2.1 OU 1: Source Control Remedial Action 29

7.2.2 OU 2: Management of Migration 30 7.2.3 OU 3: Riggs Brook 32 7.3 Question C: Has any other information come to light that could call into question

the protectiveness of the remedy? 32 7.3.1 OU 1: Source Control Remedial Action 32 7.3.2 OU 2: Management of Migration 33 7.3.3 OU 3: Riggs Brook 33 7.4 Technical Assessment Summary 33 7.4.1 OU 1: Source Control Remedial Action 34 7.4.2 OU 2: Management of Migration 34 7.4.3 OU 3: Riggs Brook 34

8. ISSUES 35

9. RECOMMENDATIONS AND FOLLOW-UP ACTIONS 37

10. PROTECTIVENESS STATEMENTS 38

11. NEXT REVIEW 39

12. DOCUMENT REVIEW LIST AND REFERENCES 40

LIST OF TABLES

Table 2-1: Chronology of Site Events 2 Table 3-1: Contaminants of Concern at Site 8 Table 4-1: Comparison between 1989 ROD and 2002 ROD Amendment 11 Table 4-2: Gallons of Transformer Oil Recovered From TWA II Area Wells 14 Table 6-1: Summary Statistics of Annual PCB Sediment Sampling Data 24

LIST OF FIGURES

Figure 3-1: Site Location Map Figure 3-2: Site Features Figure 4-1: Revised Site Plan Figure 6-1: Designated Area Soil Sampling Locations

APPENDICES

APPENDIX A: Declaration of Restrictive Covenant and Map Showing Area Covered by Covenant

APPENDIX B: Soil Sampling Data and QA/QC Summary APPENDIX C: Riggs Brook Sediment Data (1996-2005) APPENDIX D: Site Inspection Reports and Photographs APPENDIX E: ARARS and TBCS APPENDIX F: MEDEP Concurrence Letter

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LIST OF ACRONYMS

AOC Administrative Order by Consent ARAR Applicable or Relevant and Appropriate Requirement AWQC Ambient Water Quality Criteria

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

DOT Department of Transportation (U.S.)

ESD Explanation of Significant Differences

FSP Field Sampling Plan

gpd gallons per day gpm gallons per minute

HA health advisory

MCL Maximum Contaminant Level MEDEP Maine Department of Environmental Protection MEGs Maximum Exposure Guidelines MOM Management of Migration MRSA Maine Revised Statutes Annotated

NCP National Contingency Plan ND non detect NUSEPA National Environmental Policy Act NPL National Priorities List NRPA Natural Resources Protection Action

O&M Operations and Maintenance

PCBs Polychlorinated biphenyls ppb parts per billion ppm parts per million PRP Potentially Responsible Party

RiDs USEPA Risk Reference Doses RI/FS Remedial Investigation/Feasibility Study ROD Record of Decision RSOW Remedial Design/Remedial action Revised Statement of Work

SC source control SCRA Source Control Remedial Action

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SDWA Safe Drinking Water Act Site O'Connor Company Superfund Site

TI Technical Impracticability 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.

EXECUTIVE SUMMARY

This is the second five-year review performed for the F. O'Connor Superfund Site (Site) in Augusta, Maine, as required by CERCLA when hazardous substances are left onsite such that restrictions are placed on the use of the site. The purpose of the five-year review is to assess whether the remedy selected for the Site remains protective of human health and the environment. The trigger for this five-year review is the completion of the initial five-year review in September 2002.

The 1989 Record of Decision (ROD) selected a remedy to address the risks present in the site soils and groundwater from PCBs and volatile organic compounds (VOCs). These risks resulted from the operation of a salvage and electrical transformer recycling business. The 1989 remedy has subsequently been modified by an Explanation of Significant Differences (ESD) in 1994, a Contingency Remedy in 1995, and a ROD Amendment in 2002. The Site consists of three operable units (OUs).

The original Source Control remedial action included on-site solvent extraction treatment of soils to specified cleanup levels and offsite disposal of soils and sediments that exceeded the target cleanup levels. The 1994 ESD increased the cleanup levels in soil for a small area of the Site (Designated Area or DA). In 1995, a contingency in the 1994 ESD was triggered. The contingency waived the on-site treatment requirement, allowing for off-site disposal of all soil and sediment exceeding the target cleanup levels. The Source Control remedial action was completed on November 11, 1997.

The Management of Migration remedy (OU-2) specified in the 1989 ROD was changed in the 2002 ROD Amendment. The original Management of Migration remedial action included groundwater extraction and treatment and recharge into the subsurface to specified cleanup levels and included temporary institutional controls to be put in place until the groundwater met cleanup levels. The 2002 ROD Amendment included a Technical Impracticability (TI) determination that waived the cleanup standards for a limited area of the Site, replaced the groundwater extraction system with active and passive recovery of the PCB transformer oil, and made permanent the temporary institutional controls. Since the 2002 Five-Year Review, vacuum-enhanced recovery of the transformer oil from the Transformer Work Area (TWA) II occurred in 2002, 2003, 2004, and 2006 to remove transformer oil from groundwater monitoring wells. This active recovery was discontinued in 2007 as the amount recovered decreased to levels that could be recovered passively. The temporary institutional controls were made permanent on September 13, 2002 with the recording of a Declaration of Restrictive Covenant in the Kennebec County Registry of Deeds. Monitoring of groundwater continues and cleanup levels for VOCs have been met outside the TI Zone since spring 2002, and cleanup levels for PCBs have been met outside the TI Zone since spring 2006.

The 1989 ROD also addressed sediment in Riggs Brook (OU-3). The OU-3 remedy included ten years of annual monitoring of Riggs Brook sediment and periodic biota sampling. The annual sediment monitoring was completed in 2005. Sediment results have shown sporadic exceedances of the PCB threshold level that would trigger an evaluation of the need for further remedial action; seven of the ten mean annual PCB concentrations have been below the target cleanup level. The two biota results have been below the target level.

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 subsequent decision documents.

VI

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. Finalizing the O&M plan will ensure that the OU-1 remedy will remain protective.

OU-2: The remedy for OU-2 is protective of human health and the environment. Exposure pathways that could result in unacceptable risk are being controlled with institutional controls covering the entire Site. Ongoing monitoring of the groundwater beyond the TI Zone will continue to ensure that cleanup levels continue to be met.

OU-3: The remedy at OU-3 is protective of human health and the environment. Ten years of annual monitoring has shown conditions to be stable with more than 95% of the samples beneath the trigger level for additional action and the mean annual PCB concentrations meeting the target cleanup level in seven of the ten years. The biota sampling results met the target cleanup level, indicating there was no unacceptable risk.

Because the remedial actions at all OUs are protective, the Site is protective of human health and the environment.

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FIVE-YEAR REVIEW SUMMARY FORM

SITE IDENTIFICATION

Site name (from WasteLAN): F. O'Connor Company Superfund Site

EPA ID (from WasteLAN): MED980731475

Region: 1 State: ME City/County: Augusta/Kennebec

SITE STATUS

NPL status: Added on September 8, 1983

Remediation status: Ongoing

Multiple OUs? Yes Construction completion date: November 11, 1997

Has site been put into reuse? No

REVIEW STATUS

Lead agency: USEPA

Author name: Terrence Connelly

Author title: Remedial Project Manager

Author affiliation: EPA Region I

Period for this review: 02/15/07 to 09/28/07 (Time period covered by this review, 2002 - 2007)

Date of site inspection: 04/25/07

Type of review: Post-SARA

Review number: 2nd

Triggering action: Five years after first review

Triggering action date (from WasteLAN): 09/29/2002

Due date (five years after triggering action date): 09/28/2007

ISSUES:

- Samples from the Designated Area soil cover had been collected 4-8" below ground surface following the recommendation of MEDEP; MEDEP has since requested that the sampling depth be changed to 8-12" in order to demonstrate the integrity of the soil cover thickness.

- MEDEP has noted that burrowing animals could dig beneath the 12" soil cover and thereby contact the soil within the Designated Area Change where PCBs concentrations up to 10 ppm had been consolidated.

- Groundwater cleanup levels are now being met with regularity beyond the TI Zone. The decision documents did not specify criteria for determining when the Management of Migration groundwater component has been completed.

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- There were limited exceedances in the annual sediment sampling, yet of the 36 locations, the majority of exceedances have been measured at one location, 3018.

RECOMMENDATIONS and FOLLOW-UP ACTIONS:

- Change the depth of the soil cover sampling to 8-12" to address the MEDEP's concerns.

- Revise the O&M Plan to add a management approach for burrowing animals.

- EPA should develop criteria for determining when the Management of Migration groundwater component has been completed.

- Determine an approach to address sampling location 3018, either a limited excavation or continuation of monitoring.

PROTECTIVENESS STATEMENT:

Because the remedy selected and implemented has addressed the unacceptable risks found at the Site, the remedy is protective of human health and the environment. The source control remedial action was completed in 1997. Since the 2002 Five-Year Review, a TI waiver has been issued for a limited area of the Site and a restrictive covenant has been recorded that restricts certain actions without written approval from MEDEP. Concentrations of VOCs and PCBs beyond the TI Zone have met cleanup standards since spring 2002 and since spring 2006, respectively. Annual sampling of Riggs Brook sediment has been completed. Although there have been sporadic exceedances (one or two samples out of 36 each year since 2001) of the 5 ppm trigger level for further action, the mean PCB concentration for the same time period has varied between 0.38 and 1.05 ppm (the target cleanup level is 1 ppm).

OTHER COMMENTS:

IX

1.0 INTRODUCTION

This is the second five-year review for the F. O'Connor Company Superfund Site (Site) in Augusta, Maine. The purpose of this five-year review is to determine if the selected remedy 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; reviews the Applicable or Relevant and Appropriate Requirements (ARARs) specified in the decision documents for changes; discusses any issues identified during the review; and presents recommendations to address these issues. The decision documents include a 1989 Record of Decision (ROD), 1994 Explanation of Significant Differences (BSD), 1995 Contingency Remedy, and a 2002 ROD Amendment.

The United States Environmental Protection Agency, Region 1 (EPA) prepared this five-year review pursuant to the Section 121 of the Comprehensive Environmental Response Compensation, and Liability Act (CERCLA) and the National Contingency Plan. 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."

Under the regulations promulgated to implement these requirements, 40 CFR § 300.430(f)(4)(ii) of the National Contingency Plan 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."

This statutory five-year review is required since hazardous substances remain at the Site above levels that allow for unlimited use and unrestricted exposure. The triggering action for the initial statutory review was initiation of the remedial action following remedial design. EPA conducted this five-year review of the remedial actions implemented at the O'Connor Site. Work on this review was performed between April and September 2007. 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 EPA. The review was completed in accordance with EPA Guidance OSWER No. 9355.7-03B-P.

2.0 SITE CHRONOLOGY

Table 2-1: Chronology of Site Events

DATE EVENT Early 1950s F. O'Connor Co. begins operating a salvage and electrical

transformer recycling business on the site Feb 1972 Oil spill on site found to have migrated toward Riggs Brook 1978 & 1982 MEDEP conducts additional sampling events at the site, identifies

polychlorinated biphenyl (PCB) contamination 1982-1984 EPA conducts sampling events at the site, confirms PCB

contamination Sept 8, 1983 Site placed on National Priorities List (NPL) Dec 21, 1984 EPA issues Unilateral Administrative Order to O'Connor Co.

requiring it to fence five acres of the Site and sample and analyze all drums and tanks on the Site

April 1985 EPA notifies O'Connor and Central Maine Power (CMP) of their potential responsibility for contamination at the Site

May 13, 1986 O'Connor and CMP voluntarily enter into an Administrative Order by Consent (AOC) with EPA to conduct a Remedial Investigation and Feasibility Study (RI/FS) at the Site

May 19, 1986 MEDEP issues an Administrative Order to O'Connor designating the Site an Uncontrolled Hazardous Substance Site under Maine law

June 23, 1986 MEDEP issues an AOC to O'Connor and CMP May 23, 1987 EPA and MEDEP issue an amended AOC to O'Connor and CMP.

Order extends site limits to approximately 9 acres June 15, 1989 CMP submits a draft RI/FS to EPA and MEDEP for review Sept 27, 1989 ROD issued by EPA Sept 3, 1991 Consent Decree (CD) between EPA and CMP signed June 1994 MEDEP and CMP sign a Declaration of Restrictive Covenant July 11, 1994 Explanation of Significant Difference (ESD) signed Oct 20, 1994 Revised Statement of Work (RSOW) issued Oct 10, 1995 Contingency triggered by EPA July 1996 Source Control 100% Design completed Aug-Oct 1996 Phase I of Source Control completed (OU-1) Oct 1996 First sampling of OU-3, Riggs Brook sediment Oct 1996 Phase I Vacuum Enhanced Recovery (VER) completed (OU-2) Jan-May 1997 Phase II VER completed May-Nov 1997 Phase II of Source Control completed (OU-1) Nov l 1,1997 Source Control Remedial Action completed Aug-Oct 2001 Phase III VER completed (OU-2) April 2002 Draft Technical Impracticability (TI) Evaluation Report submitted to

EPA and MEDEP for OU-2 Management of Migration August 2002 Completion of First Five-Year Review Sept. 13,2002 Restrictive Covenant recorded in Kennebec County Registry of

Deeds

DATE EVENT Sept. 27, 2002 ROD Amendment issued by EPA Sept. 23, 2003 Amendment to Consent Decree signed and 2003 Statement of Work

issued Mar 29, 2004 Amendment to Consent Decree entered in US District Court for the

District of Maine Aug 2005 Tenth annual sampling event of Riggs Brook sediment Aug-Oct 2006 Fourth annual active oil recovery effort in transformer work areas

(TWA ) II April 25, 2007 Initiation of Second Five- Year Review

3.0 BACKGROUND

3.1 PHYSICAL CHARACTERISTICS

3.1.1 Setting

The F. O'Connor Site property consists of approximately 23 acres within a 28-acre property owned by Central Maine Power Company (CMP) 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 MEDEP-designated 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 as part of the source control work. 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 parts per million (ppm) were excavated and disposed offsite. Another 3,000 tons, with PCB levels less than 10 ppm, were consolidated on site 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 brought 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.

3.2 LAND AND RESOURCE USE The Site remains a mix of forest and open field, bordering the Riggs Brook wetland, and unchanged since the 2002 five-year review. The open fields encompass the formerly contaminated areas and the three reconstructed wetlands on the Site (Upland Marsh, Upper Lagoon, and Lower Lagoon). The perimeter fence was removed in a public ceremony with EPA and MEDEP in November 1997. The Site is not actively used by CMP. Surrounding land uses include low-density residential, light agricultural, commercial, fields, and forest.

The 28-acre property that includes the 23-acre Site is zoned as RRES - rural residential district, where residential development that conserves the rural character of the area is permitted. North of the 28-acre property, the adjacent property is zoned as Planned Development District. This zoning allows for "commercial and industrial uses intended to be concentrated in single or mixed use centers to ensure the most efficient provision of services and minimize impacts on residential and environmental sensitive areas, and the roadway systems". Examples of these mixed-use centers are present on Cony Road, the first road west and north of the Site. Immediately to the west of the property and extending to the intersection of Cony Road and Route 17, the zoning is Regional Business District. This zoning "provides trade and service opportunities and (is) highway oriented". South and east of the property, the zoning is also RRES, with an overlay of zoning as Resource Protection District of Riggs Brook and its wetlands, where development would adversely affect water quality, productive habitat, biological ecosystems, or areas with scenic and natural values.

Natural resources on the O'Connor property include both terrestrial and aquatic habitats. While Riggs Brook is not navigable in the stream reach adjacent to the Site, large wetland areas in the Riggs Brook watershed have been mapped by the MEDEP. The Riggs Brook wetlands have been identified as 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 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 surrounding 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 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 the three TWAs, scrap piles, oil storage tanks, and two lagoons installed to help control oil migration from the 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 excavated and 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 National Priorities List (NPL) in December 1982, and placed on the final NPL on September 8, 1983. In April 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 for the Site was issued on September 27, 1989. CMP, an identified Potentially Responsible Party (PRP) at the Site, signed a Consent Decree with the United States on September 3,1991 to undertake an investigation and remediation of the Site. CMP also acquired ownership of the property from the F. O'Connor Company in 1992.

3.5 BASIS FOR TAKING ACTION

The hazardous substances that have been released to the Site are primarily related to PCB oils and scrap from the dismantling of transformers. Based on the compounds detected on the Site during the RI, contaminants of concern were identified. These contaminants of concern were listed in Table 1 of the 1989 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.

• 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-dichIorobenzene, 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 1989 ROD selected a remedy for the Site that would meet these target cleanup goals.

In September 2002, a ROD Amendment was signed that included a TI waiver for groundwater and made minor changes to the remedies for OU-1 and OU-3. Based on the ARARs review conducted as a part of the ROD Amendment, five other VOCs were identified that had ARARs established since the 1989 ROD for which the TI waiver applied. These ARARs include Maximum Contaminant Levels (MCLs) and Maine Maximum Exposure Guidelines (MEGs) for seven VOCs and PCBs. For five out of the eight compounds, the MEG is either the same as or lower than the respective MCL. Groundwater performance standards for these eight compounds based on the ROD Amendment are also listed in Table 3-1,

Table 3-1: Contaminants of Concern at Site

Contaminants of Concern ' Target Cleanup Goal 2 Selected Remedy 3 Performance Standards 7

Soil PCBs 1 ppm 1 ppm (10 ppm DA)3 NA cPAHs 1 ppm 1 ppm (10 ppm DA) NA Lead 248 ppm 248 ppm NA Cadmium NA NA NA Copper NA NA NA Nickel NA NA NA Zinc NA NA NA

Surface Water PCBs 0.065 ppb 0.065 ppb NA Lead 1.94ppb 1.94 ppb NA Aluminum 87 ppb 87 ppb NA

Groundwater PCBs 0.5 ppb 0.5 ppb 0.05 ppb Benzene 5 ppb 5 ppb 5 ppb 1 ,4-Dichlorobenzene 27 ppb 27 ppb 27 ppb Bis 2-ethylhexylpthalate NA NA NA Chromium NA NA NA Manganese NA NA NA

Chlorbenzene NA NA 47 ppb 1 ,2-Dichlorobenzene NA NA 85 ppb 1 ,3-Dichlorobenzene NA NA 85 ppb 1 ,2,3-Trichlorobenzene NA NA NA 1 ,2,4-Trichlorobenzene NA NA 70 ppb 1 ,3,5-Trichlorobenzene NA NA 40 ppb On-Site Sediment

PCBs 1 ppm 1 ppm (5 ppm4) NA CPAHs 1 ppm 1 ppm NA Lead 248 ppm 248 ppm NA Copper NA NA NA Manganese NA NA NA Zinc NA NA NA

Riggs Brook Sediment PCBs 1 ppm 1 ppm/5 ppm 5 NA

Riggs Brook Biota PCBs NA 2 ppm6 NA

Notes: 1. Based on Results of the RI. 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)). 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. 7. Groundwater Performance Standards specified in the 2002 ROD Amendment and the 2003 SOW.

4.0 REMEDIAL ACTIONS

This section describes the remedial actions selected for and implemented at the Site. The decision documents in which the remedial actions were selected include the September 1989 ROD, July 2004 ESD, October 1995 Contingency Remedy, and September 2002 ROD Amendment.

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 Remedial Action Objectives (RAOs) 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 lead-contaminated 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 PCB-contaminated 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 1989 ROD included components for Source Control (OU-1) and Management of Migration (OU-2 and OU-3).

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 surface waters from the Upland Marsh, Upper Lagoon, and Lower Lagoon;

• Re-routing of existing drainage patterns from Upland Marsh and lagoons;

• 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; and

• Five-year reviews 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 for PCBs and for cPAHs, and 248 ppm for lead. The target cleanup goals for soils outside the Designated Area remained at 1 ppm for PCBs and for cPAHs, and 248 ppm for lead (see Column 3 of Table 3-1). The ESD also included a contingency that allowed soils and sediments to be disposed off site without solvent extraction treatment, upon approval by EPA. On October 23, 1995, EPA approved the contingency based upon the determination that the solvent extraction treatment was not feasible to meet the target cleanup goals.

The 2002 ROD Amendment did not substantially alter the Source Control component of the remedy. It made minor changes to the Operations & Maintenance Plan, adding near-surface soil sampling of the Designated Area cover coincident with each five-year review to confirm the integrity and protectiveness of the soil cover. The ROD Amendment also reconfigured the Designated Area boundary, changing it from a 25-sided to a 10-sided area (see Figure 4-1) with permanent markers placed at the turning points.

4.1.2 Management of Migration

The MOM groundwater component (OU-2) of the 1989 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 reviews of site conditions.

The MOM also included response 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;

• Implementation of public education programs; and

• Five-year reviews of site conditions.

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

In September 2002, a ROD Amendment was signed that changed the remedy originally selected in the 1989 ROD for groundwater (OU-2) and made minor changes to the remedies for OU-1 and OU-3. A comparison of the original 1989 remedy for groundwater and the modified remedy for

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OU-2 is provided in Table 4-1. The 2003 SOW describes the extent of remedial activities required at the Site based on the 2002 ROD Amendment.

Table 4-1: Comparison between 1989 ROD and 2002 ROD Amendment

1989 ROD - Groundwater Components

# 1: temporary institutional controls. This would prevent exposure to site groundwater while remediation was underway.

#2: pump-and-treat system. The appropriate sizing of the system, including the number of extraction wells, pumping rate, treatment components such as granular activated carbon, sand filters, air stripper, and number of recharge wells was to be determined during the remedial design phase. #3: a network of monitoring wells. The wells used in the RI would be assessed and augmented with additional wells in both overburden soil and bedrock.

#4: Riggs Brook sediment and biota monitoring. Brook sediments were to be monitored yearly for ten years to assess PCB concentrations. Biota sampling was to occur five years after initiation of the monitoring. #5: five-year reviews. The progress toward restoration of the groundwater and the target cleanup goal for the sediment were to be assessed during each review.

2002 ROD Amendment for OU-2

#1 permanent institutional controls. With the 1994 BSD, CMP and MEDEP signed a restrictive covenant which prevented certain activities at the site without written approval of MEDEP. #2: annual application of the VER system. The VER has been operated three times post-ROD, recovering PCB-laden oil from the overburden and bedrock. The VER will be applied annually in TW A II area wells to recover as much oil as is practical.

#3 monthly monitoring of oil levels in TWA II wells and removal using absorbent materials. Between the annual operations of the VER, the TWA II will be monitored for separate phase oil. Detected oil will be removed using absorbent material. It is expected that monitoring frequency will decrease as the amount of oil draining into the wells decreases. #4:long-term monitoring. It will be performed to track contaminant levels in the TI zone and outside it. #5: Riggs Brook sediment and biota monitoring. It will continue as OU-3, established in 1996.

#6: five-year reviews. Reviews will be conducted to ensure that the site remedy for all three OU's remains protective.

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The ROD Amendment for OU-2 required permanent institutional controls, active oil recovery, long-term monitoring of groundwater, and five-year reviews. The ROD Amendment also recognized the technical impracticability of achieving the cleanup levels required by the 1989 ROD in groundwater found on the Site (third RAO of 1989 ROD) within a reasonable timeframe. As a result, it established a technical impracticability (TI) zone for a portion of the Site (including TWA II Area) where state and federal drinking water standards are waived (see Figure 4-1).

Regarding OU-3, the ROD Amendment restated that the target cleanup goal for Riggs Brook sediment remains at 1 ppm PCBs and cPAHs. The ROD Amendment reiterated the same requirement as the!989 ROD: "if an increase in the current PCB sediment levels occurs above the 5 ppm threshold and/or the fish tissue samples are found to be greater than 2 ppm, then a more rigorous sampling effort of such contamination will be conducted to determine the need for and/or extent of further remedial actions to be undertaken within Riggs Brook, if any."

4.2 REMEDY IMPLEMENTATION Activities completed during the implementation of the remedies specified in the 1989 ROD as modified by the 1994 BSD, 1995 Contingency, and 2002 ROD Amendment are described in this section.

4.2.1 Source Control (OU-1)

Source Control was conducted 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 non-native debris, remediation of soils closest to Route 17; and construction of the support area for Phase II activities. Phase II began in May 1997 with work 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, reconstruction of the Upper Lagoon, Lower Lagoon, and the Upland Marsh and final restoration of the Site. The perimeter fence that had limited access to the Site was removed in November 1997.

Approximately 23,000 tons of soil and sediment were excavated and disposed offsite 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.

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 onsite for re-grading. As set forth in the 1994 BSD, the entire Designated Area was covered with 12 inches of clean fill. This was done 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.

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Excavated areas of the Site outside of the Designated Area were backfilled and re-graded. 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 on-site wetlands and the establishment of compensatory wetlands.

In the fall of 2002, CMP installed and surveyed 10 boundary markers simplifying the Designated Area by reconfiguring it into a 10-sided shape (see Figure 4-1). On April 24, 2007,10 soil samples were collected of the cover soil on the Designated Area coincident with this five-year review. These soils samples were collected in accordance with the draft O&M plan.

4.2.2 Management of Migration (OU-2)

Management of Migration response actions selected in the 2002 ROD Amendment included active and passive oil recovery, a technical impracticability waiver for cleanup levels in groundwater in a small area of the Site, permanent institutional controls, and monitoring groundwater to assess the potential for migration of contaminants from the Site. Investigations completed following the 1989 ROD determined that the migration of contaminants in the shallow groundwater in the downgradient direction was limited; the bedrock aquifer had low groundwater storage and therefore a relatively small volume of water. It was also concluded that the 1992 pump test had mobilized the PCB transformer oil and other contaminants vertically downward into the bedrock flow regime. Based on these findings, CMP's consultant recommended continued groundwater monitoring and the use of vacuum extraction recovery (VER) rather than conventional groundwater pumping to eliminate the potential for drawing free-floating product farther into the bedrock aquifer.

Seepage of the transformer oil into the TWA II wells has been observed since it was first induced into the wells during the 1992 pump test. The total amount of oil recovered from the five TWA II wells since their installation using a combination of VER and passive oil recovery is about 125 gallons. Approximately 79 gallons of oil (about 71%) were recovered prior to the completion of the source control work, and approximately 35 gallons (about 28%) after the completion of source control through the summer of 2002. It was because of this amount that was recovered after the successful attainment of soil cleanup, the evaluation of the technical impracticability of restoring the groundwater was initiated. Since the resumption of the VER in 2002,11.3 gallons of transformer oil have been recovered (or about 1% of the total).

During the second five-year review period, the VER system was operated in August and September of 2002, August to October 2003, August to September 2004, and in August 2006. Oil thickness monitoring at each well during the operation of the VER system showed that a decreasing quantity was recovered. Approximately 7.4 gallons of oil were recovered by the VER system in 2002, 2.5 gallons in 2003, and about 0.3 gallons in both 2004 and 2006. The system was not operated in 2005 because of equipment failure, yet there was not any increase in the amount recovered, neither passively or when the active recovery resumed in August 2006. Thus, there was no rebound after the VER suspension in 2005. The amount of oil removed from the wells using the VER system has decreased steadily over time to minimal amounts. In December 2006, the VER system was decommissioned because the rate of oil recovery using passive recovery was equal to or greater than with the VER system. Prior to 2005, the passive oil recovery program was conducted monthly. Since 2005, passive oil recovery has continued on a quarterly basis.

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Table 4-2: Gallons of Transformer Oil Recovered From TWA II Area Wells

Phase RW-101 OW-202B OW-204B OW-301B OW-302B Total Pump Test and pre­ - 29.5 0.0 15.0 7.9 52.4 VER I &II VER I & II (1996- 26.6 NS1 NS NS NS 26.6 1997) Passive 1997-2001 2.3 2.1 0.1 0.2 2.3 11.7 VERIII 2001 3.2 1.9 0.0 4.6 10.1 19.8 Passive 200 1-2002 0.2 0.2 0.0 0.0 3.5 3.9 VER 2002 0.1 0.6 0.0 0.9 5.8 7.4 Passive 2002 - 2003 0.0 0.2 0.0 0.0 0.0 0.2 VER 2003 0.2 0.5 NS 0.1 1.7 2.5 Passive 2003 ­ 2004 0.0 0.0 0.0 0.0 0.0 0.0 VER 2004 0.1 0.2 NS 0.0 0.0 0.3 Passive 2004 - 20062 0.5 0.1 NS 0.0 0.0 0.6 VER 2006 0.1 0.2 NS 0.0 0.0 0.3 Total per Well 33.4 35.7 0.1 20.8 31.3 124.8

1 NS: Not sampled 1 The VER was not operated in 2005 because of equipment failure

Prior to 2002, the MOM monitoring program (wells outside TWA II) showed that contaminants in groundwater met the 1989 ROD target cleanup goals at the perimeter of the Site. Other groundwater monitoring wells showed decreasing trends for those compounds not yet at the cleanup standard. Within the TWA n area, concentrations of PCBs, benzene, and 1,4-dichlorobenzene exceeded 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. Because the remedy was not functioning as intended within the TWA II area, CMP submitted a TI Evaluation report in June 2002.

The TI Evaluation report presented a site conceptual model that explained the technical impracticability from an engineering perspective of restoring the groundwater in the TWA II area to drinking water standards within a reasonable timeframe using the selected remedy. It then evaluated alternative remedial strategies to achieve these standards. The report concluded that none of these alternatives would achieve this Remedial Action Objective, and hence, another approach would be necessary to ensure that the remedy was protective of human health and the environment. The report included a request for a TI waiver from specific ARARs within a small area of the Site established as the TI zone.

EPA, with concurrence from Maine DEP, approved the TI Evaluation report and prepared a Proposed Plan to amend the 1989 ROD. This Proposed Plan was mailed to the public and then discussed during a public information meeting in June 2002. Following a public hearing in July 2002, the 1989 ROD was formally amended in September 2002.

As stated above, the 2002 ROD Amendment established the TI zone which 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 TI zone have been monitored to ensure that groundwater performance standards are met outside of the TI zone.

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

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I 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

• 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 was recorded in the Kennebec County Registry of Deeds on September 13,2002. A copy of the covenant and a map showing the area covered by the covenant are included in Appendix A.

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-welI 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 transformer oil.

Since the last five-year review, groundwater performance standards for the seven VOCs specified in the 2002 ROD Amendment have been met in the monitoring wells outside of the TI zone. PCBs have met the performance standard in the monitoring wells outside of the TI zone since April 2006. Performance standards for the VOCs have been met for wells within the TI zone but outside of the TWA n area since April 2004. Within the TWA II Area, concentrations of PCBs and several VOCs exceed the performance standards.

4.2.3 Riggs Brook (OU-3)

Central Maine Power conducted annual sediment monitoring of Riggs Brook for 10 years (1996­2005) as required by the 1989 ROD. Biota sampling in Riggs Brook, which was also required by the ROD, was completed in 1997 and 2000. At EPA's request, the 2000 annual program was supplemented with a sampling grid with 51 locations adjacent to Riggs Brook in Areas 2 and 3 of the source control area of the Site.

Biota was sampled in 1997 following completion of the source control work. The next biota sampling event that had been scheduled for 2002, was instead completed in 2000 at the request of EPA.

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 a part of the Community Meetings leading up to and during the source control work. Due to minimal interest expressed by the public regarding Riggs Brook or the Site since the completion of the source control component of the work, further meetings have not been held.

4.3 SYSTEM OPERATIONS/O&M The draft May 2007 O&M plan describes the long-term activities for the Site, including inspections, soil cover sampling, routine maintenance, and repairs as necessary. EPA, MEDEP

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and CMP are finalizing the O&M plan. O&M activities for OU-1 include inspections, wetland construction compliance monitoring and soil sampling of the cover of the Designated Area as a part of five-year reviews. For OU-2, O&M activities include checking the integrity of the groundwater monitoring wells. Sediment and biota monitoring have been completed at OU-3, and therefore, there are no O&M activities associated with OU-3.

Site inspections for OU-1 have been performed by CMP. The inspections have reported that vegetation is well developed, thicker in some areas than others, and that drainage channels are in good shape and functioning as designed. Annual mowing has not been routinely performed as planned in order to allow the vegetation to establish itself. However, since 2002, the TWA II area has been mowed to facilitate access to the wells, and the Designated Area was mowed in 2006. Future mowing at the site will be conducted in accordance with the O&M Plan. Minor ruts in the access road were filled in 2003; and the 2007 site inspection noted low spots near the entrance, but otherwise, the access road is in good repair.

Compliance monitoring to evaluate wetland vegetation survival and general wetland system recovery was performed in 1998,1999,2000, 2002, (years 1, 2, 3, and 5) and the field investigation for the final monitoring in year 10 was performed this summer. The 2002 Five-Year Review assessment of the goals of the project concluded that the restoration had at that time:

• Provided vegetative cover and a diverse plant community,

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

• reestablished wetland functions and values.

The 2007 monitoring measured slightly less acreage and less vegetative cover than was recorded prior to remediation, yet the function and value acreage has increased. The restored wetlands have developed wet meadow communities comprised of a dominance of wetland species with a mixture of old-field upland species, which is consistent with the characteristics of natural communities. In addition to the wetland species, the 2007 monitoring identified hydric soil conditions and evidence of hydrology. The wetland communities provide potentially diverse habitat for aquatic and wetland dependent species.

O&M costs for OU-1 include site inspections, soil sampling and site repairs. O&M costs were originally estimated at approximately $15,000 for year 1 and $3,000 for years 2 through 10. Costs for O&M for years 5-10 have been lower than originally estimated in the O&M plan because the Site has not been mowed annually and the only repair work was minor access road repair conducted in 2003.

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 CMP's consultant, groundwater monitoring costs are approximately $25,000 per year. Since there is no O&M associated with OU-3, there are no associated O&M costs.

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5.0 PROGRESS SINCE LAST FIVE-YEAR REVIEW

This is the second five-year review for the Site. The first five-year review, completed by EPA in September 2002, assessed the three operable units and made the following conclusions:

• The remedial action for OU-1 has controlled exposure pathways and ongoing O&M would ensure that the OU-1 remedy remains protective of human health and the environment;

• The remedial action for OU-2 was not protective because of the presence of residual oil in the subsurface and PCB and VOC concentrations above target cleanup levels; and

• The remedial action for OU-3 was expected to be protective upon completion of the ten-year sampling program.

Additionally, the 2002 FYR made the following recommendations:

• Implement necessary regulatory changes to the OU-2 remedy;

• Analyze groundwater at lower detection limit to determine if remedy meets Maine MEG for PCBs;

• Resample two source control locations that exceeded the sediment 1 ppm PCB level;

• Update the O&M plan;

• Continue oversight of wetlands restoration effort for years 5 and 10 events; and

• Re-evaluate the institutional controls to reflect the current site conditions.

The following describes the progress made in addressing these recommendations following the 2002 FYR:

Implement necessary regulatory changes to the OU-2 remedy

As noted in earlier Section 4.0 Remedial Action, subsequent to the 2002 FYR, EPA issued a ROD Amendment on September 27, 2002. This ROD Amendment included a TI waiver for groundwater for a limited area of the Site while maintaining the groundwater standards established in the 1989 ROD for the remainder of OU-2. The ROD Amendment also added active and passive oil recovery in the TWA II area, recording of a restrictive covenant between MEDEP and CMP, and performance standards for five VOCs that did not have standards at the time of the 1989 ROD.

Active recovery of the transformer oil was performed during late summer-fall 2002,2003, 2004, and 2006. Passive recovery, using absorbent materials placed within the TWA II monitoring wells, was performed monthly until 2005 and then quarterly since then. Approximately 7.4 gallons of oil were recovered by the VER system in 2002, 2.5 gallons in 2003, and about 0.3 gallons in 2004 and 2006.

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Analyze groundwater at lower detection limit to determine if remedy meets Maine MEG for PCBs

Groundwater monitoring continued under a Long-Term Monitoring Plan approved by EPA after review and comment by MEDEP. All of the VOC standards have been met beyond the TI Zone since April 2002 (11 sampling events). With the new PCB standard an order of magnitude lower than the standard set in the 1989 ROD, the PCB detection limit was lowered to 0.047 ppb to allow comparison to the Maine MEG. This new standard has been met beyond the TI Zone since April 2006 (3 sampling events).

Resample two source control locations that exceeded the sediment 1 ppm PCB level

Sediment sampling continued through 2005, and included the two source locations that had inadvertently been included in the expanded 1998 sampling event. Thirty-six samples were collected annually from 2001 through 2005. One to two samples from the 36 locations were above the 5 ppm trigger level for further action. The annual mean PCB concentration for the same time past five years varied between 0.38 and 1.05 ppm (the target cleanup level is 1 ppm).

Update the O&M plan

The O&M Plan has been revised and is now being reviewed by the agencies.

Continue oversight of wetlands restoration effort for years 5 and 10 events

As noted above in Section 4.3, the final assessment of the restored wetlands was submitted to the agencies in September 2007. The assessment concluded that the function and value acreage of the wetlands have been increased when compared to the pre-remediation totals.

Re-evaluate the institutional controls to reflect the current site conditions

The Declaration of Restrictive Covenant had been signed by MEDEP and CMP in June 1994 but had not been recorded and was being held in escrow by MEDEP. As part of the ROD Amendment, MEDEP agreed to record the document and did so at the Kennebec Registry of Deeds on September 13, 2002.

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6.0 FIVE-YEAR REVIEW PROCESS

6.1 ADMINISTRATIVE COMPONENTS EPA, the lead agency for this five-year review, notified Maine DEP and CMP at the beginning of 2007 that the five-year review would take place during the spring and summer of 2007. A meeting was held at CMP's Augusta office on February 15, 2007 with the two agencies, CMP and their consultant, Woodard & Curran, to discuss the site status and components of this five-year review. Claudia Sait of MEDEP was part of the review team.

The schedule established by EPA included completion of the review by September 2007.

6.2 COMMUNITY INVOLVEMENT EPA prepared a public notice announcing the five-year review and requesting public participation. The notice was published May 24, 2007 in the Kennebec Journal, a daily newspaper in Augusta, Maine. Since the publication of the notice, there has been no response from the public to either MEDEP or EPA regarding the five-year review. This level of response was similar to that of the previous five-year review and to the 2002 ROD Amendment public meeting and hearing.

The Administrative Record for the Site is available at the Lithgow Public Library in Augusta. Given space constraints and the lack of interest in the Site, the Administrative Record is stored in the library's basement. According to the library's research librarian, there has been little interest in the site documents.

6.3 DOCUMENT REVIEW This five-year review consisted of a review of relevant documents including decision documents, work plans, various monitoring reports, and O&M inspection reports. These references are listed in Section 12.0 at the end of this report.

6.4 DATA REVIEW

6.4.1 Source Control OU-1

Since the last five-year review in 2002, semi-annual site inspections continue to be conducted by CMP to observe any physical changes at the Site that would compromise the remedy. Wetlands construction monitoring was conducted in years 5 (2002) and 10 (2007) after the completion of the source control work. In addition, soil sampling was conducted on the Designated Area in 2007 to confirm the integrity of the soil cover.

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Inspection reports conclude that vegetation is well developed, drainage channels are in good condition and functioning as designed. The 2007 wetland monitoring report concluded the natural and restored wetlands are dominated by wetland species consistent with natural communities. Overall, the restored wetlands are providing to a number of targeted functional values.

Soil sampling of the Designated Area was completed on April 24, 2007. Ten composite soil samples were collected from randomly selected sample locations from a total of 183 grid points within the 10-sided Designated Area. Sample locations are shown on Figure 6-1. Soil samples were collected from four to eight inches below the ground surface, and analyzed for PCBs in accordance with the QAPP Amendment (W&C, 4/17/07). The purpose of the soil sampling was to demonstrate the integrity of the soil cover on the Designated Area, and compare the PCB concentrations of the soil samples to the remedial goal of 1 mg/kg. PCBs were detected at four sampling locations shown below; all were well below the soil remedial goal of 1 mg/kg.

Soil Sample location Total PCBs (mg/kg)

1009.07 0.032

1036.07 0.18

1118.07 0.032

1121.07/Duplicate 0.023/0.028

A review of associated quality control results was conducted to determine the quality of the PCB data. All of the quality control results were compliant with validation criteria indicating that the data are of sufficient quality for its intended end use of characterizing soil conditions at the Site. Soil analytical data, evaluation and quality control/quality assurance summaries are provided in Appendix B.

6.4.2. Management of Migration OU-2

The results of the MOM monitoring, excluding the five wells located within the TWA II area, conducted between April 2002 and April 2007 were reviewed. Based on the ROD Amendment, groundwater performance standards were established for PCBs (0.05 ug/L) and seven VOCs (see Table 3-1). Limited data from wells within the TWA II Area are discussed separately.

PCBs. From April 2002 until September 2005, the groundwater performance standard for PCBs (0.05 ug/L) was exceeded four times outside the TI zone in wells MW-501 and MW-503. The highest total PCB concentration detected outside the TI zone was 0.91 ng/L detected in MW-503 in September 2004. PCBs were not detected in wells located outside of the TI zone in 2006 or in April 2007. There were two additional exceedances of the PCB performance standard at two wells (MW-104B and MW-510A) within the TI zone but outside of the TWA II Area. Monitoring wells MW-104B, MW-501 and MW-503 are located downgradient of the TWA II Area. These exceedances are summarized below.

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Total PCBs Well Date (ug/L)

Outside TI zone

MW-501 4/29/2002 0.06

MW-503 9/9/2003 0.068

MW-503 9/21/2004 0.91

MW-503 9/12/2005 0.5

Outside TWA-II Area

MW-104B 4/20/2005 0.24

MW-510A 9/12/2005 0.14

VOCs. From April 2002 to April 2007, concentrations of VOCs detected in MOM monitoring wells have been decreasing and groundwater performance standards have been met at wells outside of the TI zone. The only exceedances of the performance standards have been in two bedrock wells (MW-104B and OW-201B) located outside and downgradient of the TWA II Area but within the TI zone. Between April 2002 and September 2003 concentrations of 1,2-dichlorobenzene (performance standard 85 ug/L) ranged from 87 to 110 ug/L, and concentrations of 1,4-dichlorobenzene (performance standard 27 ug/L) ranged from 28-44 ug/L. Concentrations of 1,2-dichlorobenzene and 1,4-dichlorobenzene have been below the performance standards at these two wells since April 2004. In addition, a Mann Kendall trend test was performed that indicated a statistically significant downward trend in the 1,4-dichlorobenzene concentrations in these wells.

Well MW-106B (outside the TI zone) 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. Since April 2002, low levels of VOCs have been detected at MW-106B and are generally decreasing; total VOCs range from approximately 23 ug/L in April 2002 to approximately 1 ug/L in April 2007. There have been no exceedances of groundwater performance standards for VOCsatMW-106B.

Monitoring wells MW-507A and MW-508B (outside of the TWA II Area, but within the TI zone) are placed in the bedrock trough, which is the primary discharge pathway for groundwater from the upper portions of the Site. These wells monitor the till/bedrock migration pathway (MW-507A) and the secondary bedrock migration pathway (MW-508B). Since April 2002, several VOCs have been detected at MW-507A, but none has exceeded groundwater performance standards. These concentrations have been fluctuating and generally decreasing; total VOCs ranged from approximately 100 ug/L in 2003 to less than 1 ug/L in 2007. The bedrock concentrations of VOCs observed in MW-508B have been non-detect since September 2002.

TWA II Wells. The groundwater from the five wells in the TWA II area have typically not been sampled because the observable oil in these wells would not give representative results of the dissolved concentrations. However, observation well OW-204B has not shown any indication of

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i transformer oil since April 2000, and thus, has been sampled since 2002. The concentration of PCBs detected at OW-204B has been decreasing (maximum of 0.81 ppb was detected in April 2002), and has been non-detect since April 2006. Very low concentrations of VOCs have been detected since 2002, and have been non-detect since September 2006.

Observation well OW-301B has not had observable transformer oil since the 2003 VER, and was sampled for the first time in April 2007. Concentrations of PCBs in groundwater at OW-301B exceeded the groundwater performance standard at 74 ug/L. Concentrations of five out of eight VOCs exceeded performance standards. It should be noted that due to the damaged casing at OW-301B, a properly purged sample could not be obtained, and a bailer was used to collect the sample.

Groundwater samples have not been collected from the other TWA II wells because of the presence of residual transformer oil. Therefore, the samples collected from OW-204B and OW­30IB are not considered to be representative of actual dissolved contaminants in the TWA II groundwater.

To date the MOM monitoring program has shown that groundwater performance standards for PCBs have been met for wells outside the TI zone since April 2006, and performance standards for VOCs have been met for wells outside the TI zone since April 2002. From April 2002 to September 2005, the only PCB exceedances in wells outside of the TI zone were in MW-501 and MW-503. At monitoring wells within the TI zone, but outside of the TWA II Area, there have been no exceedances of PCBs since April 2006, and no exceedances of VOCs since April 2004. Within the TWA II area, concentrations of PCBs, and several VOCs have exceeded the groundwater performance standards. 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. As stated above, based on the TI waiver established in the 2002 ROD Amendment, groundwater performance standards for PCBs and VOCs are waived within the TI zone (including the TWA II Area).

6.4.3 Riggs Brook OU-3

This section reviews ten years of Riggs Brook sediment data (1996-2005) and two years of biota data (1997 and 2000). A total of 364 samples were collected over these ten years and analyzed for PCBs. The sampling program began with 24 locations as specified in the 1996 Sampling and Analysis Plan and expanded to 36 locations in 2001, after an additional 51 locations, in a more-closely spaced grid, were sampled in 2000. The sediment data is summarized in Appendix C. PCB concentrations have exceeded the 5 ppm trigger level at a few locations. PCB concentrations in biota have not exceeded the 2 ppm threshold level. Sampling results are discussed below.

• Over the past 10 years, 208 sediment samples have been analyzed from the 21 locations adjacent or downgradient of the site identified in the Sampling and Analysis Plan (SAP). Only seven of these samples from four locations exceeded 5 ppm PCBs (three at location 8006, two at location 8004, and one at location 8013 and location 9C100).

• As a result of the PCB results at location 8006, a more rigorous supplemental sampling plan was undertaken in 2000. Fifty-one locations on a grid around 8006 were sampled. Only four of these samples exceeded 5 ppm PCBs. Ten of the supplemental grid locations including the four that exceeded 5 ppm PCBs were added to the annual

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sampling program. Over the next 5 years only one sample at an added location exceeded the 5 ppm threshold. Overall, of the 101 samples taken over 6 years in the supplemental grid area, only 5 samples exceeded 5 ppm PCBs, and no location has more than one exceedance.

• In 1998 two locations, 3018 and 8039, were mistaken for locations 8004 and 8013, respectively, and sampled. CMP continued to sample these locations in subsequent years. Location 3018 exceeded the 5 ppm threshold on a number of occasions, while location 8039 was consistently non-detect for PCBs.

Location 3018 is actually located within Area 3 of the Source Control operable unit (OU­1), and is outside the original Riggs Brook area of investigation. However, as noted in Figure 2 of the 2007 wetland monitoring report, this location appears to be within the delineated wetland, and thus, should be assessed using the criteria set forth in the 1989 ROD.

• PCB concentrations in 20 biota samples taken during both the 1997 and 2000 sampling events were below the target level of 2 ppm wet weight. (The 2000 sampling was changed from the originally scheduled date of 2002 at the request of EPA and USFWS.) A comparison of the two sampling events concluded that there was a decreasing trend in PCB concentrations during the 3-year period. The results of the biota sampling were presented in the 1997 and 2000 Riggs Brook Sediment and Biota Monitoring Reports.

The results of the 10-year sampling program show the sediments in Riggs Brook to be stable, with no indication that PCBs are migrating or increasing in concentration. Over 95% of the samples were below the PCB action trigger level of 5 ppm; the annual mean varied between 0.38 to 1.93 ppm (three years greater than 1 ppm, seven years 1 ppm or less). See Table 6-1 below for a statistical summary of the ten years of data and Appendix C for all the data. The sporadic exceedances of PCBs above the 5 ppm trigger level within Riggs Brook appear to be the result of the variability of sediment deposition near the brook. The biota samples were all below the threshold limit for the Site.

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Table 6-1: Summary Statistics of Annual PCB Sediment Sampling Data

Year Number above Number of Maximum Maximum Mean Action Trigger Non-Detects/ Concentration Concentration Concentration1

Level/Sampling Sampling ppm (mg/kg) Location ppm (mg/kg) Locations Locations

1996 0/24 9/24 4.1 3018 0.41

1997 2/24 14/24 29 8004 1.72

1998 2/24 13/24 16.8 8006 1.15

1999 1/26 19/26 14 8006 0.75

2000 1/26 20/26 10.4 8006 0.74

2000 4/51 9/51 12.6 9BOOO 1.59 (supp)

2001 1/36 18/36 6.1 3018 0.40

2002 1/36 15/36 5.6 3018 0.58

2003 0/36 17/36 4.4J 3018 0.38

2004 2/36 12/36 18 3018 1.00

2005 2/36 11/36 8J 3018 1.05

In calculating the mean, the detection limit value was used for non-detect locations and where duplicate samples were collected, the higher concentration value was used. Both of these methods therefore would produce a higher average concentration.

6.5 SITE INSPECTION

A site inspection was conducted on April 25, 2007 with representatives from EPA, Maine DEP, CMP and CMP's contractor. The inspection included a walkover focusing on the Designated Area boundary and observations of vegetated cover, monitoring wells and restored wetland areas. The Site is no longer secured with fencing and not all of the monitoring wells have secure locks. In 1997, EPA determined that the fence was 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 appeared to be well established, given that the inspection was performed at the beginning of the growing season. The riprap spreader swales constructed to direct runoff from the lagoons toward Riggs Brook are in good repair other than a limited area below the Lower Lagoon where the underlying geotextile was visible. A small amount of soil was observed to have eroded from the base of the riprap between the upper and lower lagoons. A small low area was observed on the dirt access road near Route 17, along the edge of the Designated Area between boundary markers A and B. These areas will be repaired in accordance with the O&M Plan for the Site. The site inspection report, including site photos, is included in Appendix D.

CMP personnel check the Site during the quarterly passive recovery, the semi-annual monitoring

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events, and following major storm events. CMP reported that they have been mowing the top grassy portion of the Site (including the Designated Area) annually for the last few years. Since the Site was farmland in the 1950's the perimeter trees and other vegetation have become well established in areas where there were no active operations.

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 recorded in the Kennebec County Registry of Deeds on September 13, 2002. CMP and the RP contractor reported that there have been no known violations of the terms of the Covenant: no use of the groundwater; no activity that has disrupted remedial or monitoring measures; and the Site is maintained in a condition adequate to ensure the continued compliance with all applicable standards.

A follow-up inspection was performed on July 26, 2007 to assess the vegetative cover during the height of the growing season. Wildflowers were observed in the uplands (Black-eye Susan's, Queen Anne's lace, blue curls, goldenrod), while grasses and perennials, such as crown-vetch, have provided dense cover on the slope from the upland area down to the Riggs Brook wetlands. No areas of distressed vegetation were observed on the Site during the initial and follow-up site inspections.

6.6 INTERVIEWS

General discussions and observations were documented during the soil sampling on April 24, 2007 and the site inspection on April 25, 2007.

Roy Koster, CMP, noted that CMP personnel visit the Site on a quarterly basis to check the wells in the TWA II area for floating oil. When present, oil is collected using absorbent pads that are then taken to a CMP transfer facility in Augusta. In addition to these scheduled visits, CMP personnel also visit the Site after extreme weather events. CMP has no plans to develop the site; noting the Riggs Brook wetlands, the restored wetlands, and the steepness of the slope, CMP believes that there is limited acreage that would be available for redevelopment. Additionally, for the past several decades, most of the development in Augusta has been on the west side of the Kennebec River.

Mr. George Soucy, one of the Code Enforcement Officers for the City of Augusta, was contacted by telephone on August 2, 2007. He knew of the Site and its location and said he has received several inquiries about the availability of the property for development. As a 28-acre lot on a main highway with public water and sewer nearby, it has generated interest regarding its availability.

Mr. Soucy provided information on the current zoning in the area of the Site and provided the internet access to obtain the tax and zoning maps. He did not express any concerns about the activities that have been completed and was pleased to hear that groundwater had been meeting cleanup levels. 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 public notice in the Kennebec Journal on May 24, 2007.

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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 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 and the 2002 ROD Amendment along with current ARARs and TBCs are provided in Appendix E of this Report for reference.

7.1 QUESTION A: IS THE REMEDY FUNCTIONING AS INTENDED BY THE DECISION

DOCUMENTS?

ANSWER A: YES, the source control is complete with inspections and sampling indicating the soil cover is functioning as intended; the management of migration is meeting cleanup levels outside the TI zone; and, ten years of sampling of Riggs Brook sediment indicate the performance standards have been attained 95% of the time.

7.1.1 OU-1: Source Control

Remedial action performance and monitoring results. The 2002 FYR noted that the site was remediated in accordance with the requirements of the 1989 ROD, as modified by the 1994 BSD. The soil excavation and covering of the Designated Area with clean fill reduced public health and environmental risks from direct contact with contaminated soils and sediments, and exposure to surface water. Site inspections since the completion of this component of the work and soil sampling performed in April 2007 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 the draft O&M plan to ensure the long-term integrity of the soil cover over the Designated Area.

hi accordance with the 2002 ROD Amendment and Statement of Work (SOW, Appendix II of the March 2004 Amendment to Consent Decree), the Designated Area boundary was simplified to a 10-sided shape and on-site markers were installed to clearly define marked boundaries (see Figure 4-1). In addition, shallow soil samples collected (see Figure 6-1) of the cover soil show that very low concentrations of PCBs were detected at several locations, but were well below the required cleanup level of 1 ppm. Therefore, the integrity of the soil cover on the Designated Area is intact and the soil cover is functioning as intended.

The 2007 wetland monitoring report concluded the natural and restored wetlands are dominated by wetland species consistent with natural communities. Overall, the restored wetlands are providing to a number of targeted functional values.

Operations and Maintenance Costs. Maintenance of the Site has only been necessary on the gravel access road and has been effective. As discussed earlier in this report, minor erosion was observed on the access road in 2003 and was repaired. During the April 2007 inspection, a small erosion area was observed on the access road and a small erosion area was observed in a drainage swale. These areas will be repaired in accordance with the O&M plan. Neither the minor erosion that was noted in 2003, nor the erosion areas that were observed in 2007 were deep, and they will 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. The O&M costs presented do not include the site inspections that are performed by CMP or the wetland monitoring contractor.

Opportunities for Optimization. Now that the vegetation on the Site is well established, it is proposed that the mowing of the Designated Area be conducted in accordance with the O&M plan.

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 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 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 A. The CMP consultant has reported that no activities have been observed on the Site that would have violated the institutional controls. As noted earlier, the Site is checked by CMP or its consultant during the quarterly passive recovery of transformer oil events, the semi-annual groundwater sampling events, and after significant weather events.

7.1.2 OTJ-2: Management of Migration

Remedial Action Performance and Monitoring Results. Review of relevant MOM documents and results of the semi-annual groundwater monitoring indicates that the MOM remedy is functioning as intended outside the TI zone. As described earlier in this report, concentrations of PCBs outside of the TI zone have met the groundwater performance standard since April 2006, and VOCs have met performance standards since April 2002 with both PCBs and VOCs trending downward. Small amounts of residual transformer oil, containing PCBs and VOCs, remain in fractures in the clay and to a limited extent in bedrock. However, because of the inherent surface tension within the clay, little movement of the oil has been observed.

Groundwater remediation with the VER system and monthly passive transformer oil recovery has removed a total of approximately 121 gallons of the oil from the TWA II wells since 1992, including approximately 11 gallons since 2002. Groundwater monitoring results indicate decreasing trends in concentrations of VOCs over the entire Site.

Monitoring wells along the boundary of the TI zone continue to be monitored to ensure that groundwater performance standards are met outside of the TI zone.

Operations and Maintenance/Costs. There have been no O&M costs for MOM other than the water quality monitoring. No maintenance has been required for the wells. Groundwater monitoring costs are approximately $25,000 per year.

Opportunities for Optimization. The groundwater-monitoring network should be re-evaluated and the locations and number of wells included in the network modified based on agreement by EPA, 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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To determine if further amounts of oil can be extracted from these wells, as of 2007, the passive oil recovery program is continuing on a quarterly basis.

Indicators of Remedy Problems. With the remedy modified in 2002 to include a Technical Impracticability waiver for a limited area of the Site, the remedy is functioning as intended.

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.

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 after the PCB hot spot removal in 1997, the remedy is functioning as intended by the 1989 ROD, 1994 RSOW, 2002 ROD Amendment and the 2004 SOW. Ten years of monitoring at Riggs Brook have been completed; sediment monitoring was conducted annually 1996 to 2005, and biota monitoring was conducted in 1997 and 2000.

Over the last ten years, PCB concentrations in sediment have exceeded the 5 ppm trigger level in only a few sporadic locations (one or two out of 24 -36 locations per year), which appears to be the result of variability of sediment deposition near Riggs Brook. In addition, there is no indication that PCBs are migrating or increasing in concentration. Mann-Kendall statistical trend analysis does not show any statistically significant trends. The 1997 and 2000 biota sampling events have shown that PCB concentrations did not exceed the 2 ppm threshold limit, and in fact were less than 1 ppm wet weight. The small amount of PCBs detected in Riggs Brook do not appear to have adversely affected biota in the stream. Therefore the remedy is functioning as intended.

Operations and Maintenance/Costs. Since the remedial action for OU-3, monitoring, has been completed, there are no other operations or maintenance occurring at Riggs Brook. Based on information from the consultant for CMP, annual monitoring costs for Riggs Brook sediment monitoring were approximately $10,000.

Opportunities for Optimization. Although the ten years of sampling required by the ROD have been completed, because of the frequent exceedance of the trigger level in sample location 3018, it may be more efficient to perform a limited removal of sediment (i.e., less than a cubic yard) rather than to continue to monitor it indefinitely.

Indicators of Remedy Problems. Based on annual sediment and biota monitoring, there do not appear to be any significant indications of remedy problems. Although PCBs have been detected each year in one or more sediment samples, of the 309 samples collected during the ten years of monitoring and the 51 added in 2000 as part of a supplemental grid, only 12 and 4 samples, respectively, exceeded the trigger level of 5 ppm at a few locations. Additionally, the mean annual PCB concentration has been below or just above the target cleanup level (1 ppm) in the last four years of monitoring. Overall concentrations of PCBs appear to be stable, with no indication that PCBs are migrating or increasing in concentration. In addition, concentrations of PCBs in sediment do not appear to be impacting biota (all samples less than the threshold level of 2 ppm).

Implementation of Institutional Controls. The institutional controls discussed in Section 4.2.2 apply to the entire Site, including OU-3, and there have been no infractions of these controls.

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7.2 QUESTION B; ARE THE EXPOSURE ASSUMPTIONS. TOX1C1TY DATA. CLEANUP LEVELS AND

REMEDIAL ACTION OBJECTIVES (RAOs) USED AT THE TIME OF REMEDY SELECTION

STILL VALID?

ANSWER B: YES, though there have been some limited changes in the toxicity data and cleanup levels since the 1989 ROD, the RAOs used at the time of the remedy selection, as modified, are 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 1989 ROD and 2002 ROD Amendment have been reviewed. In addition, a review of current ARARs, promulgated, amended or revised between 2002-2005 has been conducted. Since the SCRA has been completed, ARARs for soil contamination cited in the ROD and ROD Amendment have been met.

There are no current chemical-specific ARARs that apply to soil contaminants at the Site. The 1989 ROD target cleanup goals of 1 ppm for PCBs, 1 ppm for cPAHs and 248 ppm for lead used to remediate the areas of the Site outside the Designated Area are still the considered protective. Although the target cleanup goals inside the Designated Area were 10 ppm for PCBs, 10 ppm for cPAHs and 248 ppm for lead, the top 12-inches of soil on the Designated Area is comprised of clean fill. In addition, the April 2007 analysis of the soil cover on the Designated Area shows that the concentrations of PCBs in the soil cover are less than 1 ppm. Therefore, the source control component completed at OU-1 remains protective.

The only TBC guidance written since the last five-year review is EPA's Supplemental Guidance for Assessing Susceptibility from Early-Life Exposures to Carcinogens, March 2005. This risk assessment guidance is discussed below.

Changes in Exposure Pathways. Seven exposure scenarios were identified in the Endangerment Assessment, including three potential current exposures and four potential future exposures. According to the 2002 ROD Amendment, following the completion of the source control component of the remedy, only two potential exposure pathways remained. They included future ingestion of groundwater from within the bedrock, and ingestion offish caught in Riggs Brook. Since the 2002 five-year review, EPA released draft guidance on the vapor intrusion pathway.

Changes in Toxicity and Other Contaminant Characteristics. The contaminants with the greatest cancer risk potential at the Site were PCBs and cPAHs. Since the last five-year review was com­pleted in 2002, the cancer slope factor (CSF) for PCBs has decreased from 7.7 (mg/kg/day)-l' to 2 (nig/kg/day)-!, as cited in EPA's Integrated Risk Information System (IRIS) database. A decrease in a cancer slope factor indicates that potential risk from exposure to contaminants is lower than previously calculated. The CSF for cPAHs, evaluated using benzo(a)pyrene, has remained the same at 7.3 (mg/kg/day)-l, indicating no notable change in the risk of cancer at the Site.

Risk Reference Doses (RfDs) are values used to quantify the risk associated with specific

1 (mg/kg/day)-l is the accepted shorthand practice in the risk assessment field where this would be read as 7.7 (in this example) per milligram of contaminant (PCBs) per kilogram of body weight per day, where the 7.7 is the risk per unit dose.

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contaminants. Since the last five-year review, the RfD for PCBs has remained the same at 2 E-5 mg/kg/day2, as cited in the EPA IRIS database (2007). The RfDs for cPAHs are not available in the IRIS database. In addition, the EPA blood lead level of concern (10 ug/dL) has not changed. Review of this information indicates that the remedy remains protective.

Changes in Risk Assessment Methods. The only change in risk assessment methods since the last five-year review is the manner in which cPAHs are evaluated based on EPA's Supplemental Guidance for Assessing Susceptibility from Early-Life Exposures to Carcinogens, March 2005. This guidance document recommends application of an age-dependent adjustment factor (ADAF) to cancer slope factors of constituents with a known mutagenic mode of action when quantifying risks to children younger than 16 years. Benzo(a)pyrene has been identified as such a compound. While these changes may have an effect on calculated risks (and a decrease in the potential cleanup level for cPAHs), the protectiveness of the remedy would not be affected. Carcinogenic PAHs were remediated to 1 ppm throughout the Site. Even within the Designated Area, where PCBs remain with concentrations between 1 and 10 ppm, the extensive confirmatory sampling for the source control remedy found that cPAHs were always co-located with PCBs, and that the corresponding cPAH concentrations are only slightly above 1 ppm. Therefore, as long as the soil cover over the Designated Area is maintained, there is no potential for exposure, and the target cleanup goals set in the 1989 ROD, as modified in the 1994 ESD, remain protective of the exposures and receptors identified for the Site.

The methods used to assess risk of constituents in air have changed since the 1988 Endangerment Assessment was conducted, primarily with the evaluation of vapor intrusion from the subsurface into indoor air of a structure. However, because soils at the Site have been remediated, and institutional controls are in place where high levels of groundwater remain, this exposure pathway is not a concern.

Expected Progress Towards Meeting RAOs. The source control component of the remedy has been completed and met the remedial action goals for OU-1.

7.2.2 OU 2: Management of Migration

Changes in Standards and TBCs. There has been no change to the ARARs list for groundwater since the 2002 FYR. The 2002 ROD Amendment lists MCLs and 1992 Maine MEGs as chemical-specific ARARs, and the 2004 Statement of Work identifies the more conservative 1992 Maine MEGs as groundwater performance standards (see Table 3-1) where there are both federal and state standards.

The ROD amendment also established a waiver of these chemical-specific ARARs for a limited portion of the Site (the TI zone) on the basis on technical impracticability.

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 as long as water is not used for drinking water with in the TI zone. As noted above, since the last review, EPA has issued draft guidance on exposure to volatiles in indoor air originating from shallow groundwater. A review of current groundwater data was

2 This would be read as 2 X 10~5 milligrams of contaminant per kilogram of body weight per day where the measured concentration would be compared to this value for non-carcinogenic risks. If the measured concentration were greater than the calculated value using this equation, then this would indicate a potential risk.

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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 (ND to 30 ug/L) and 1,4-dichlorobenzene (ND to 11 ug/L), were below the groundwater performance standards (85 and 27 ug/L, respectively), at one well (507A) in the shallow aquifer during the 2006-2007 sampling.

These concentrations are not expected to adversely affect indoor air in potential future buildings. The highest concentrations of these two compounds are well below the EPA target groundwater concentrations set in the draft guidance (protective of vapor intrusion) of 2,600 ug/L for 1,2-dichlorobenzene and 8,200 ug/L for 1,4-dichlorobenzene. Bedrock groundwater was not evaluated for this pathway, as shallow groundwater is the most likely 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 Toxicity and Other Contaminant Characteristics. As discussed above, the 2002 ROD Amendment established groundwater performance standards for seven VOCs and PCBs. These are listed in Table 3-1. Since the last five-year review in 2002, the oral CSF for PCBs decreased to 2 (mg/kg/day)-l, indicating a decrease in potential risk. The oral CSF for benzene increased from 2.9 E-2 (mg/kg/day)-l to a range of upper-bound CSF of 5.5 E-2 (mg/kg/day)-l, indicating an increase in potential risk. CSFs were not available in EPA's IRIS database for 1,4-dichlorobenzene and other VOCs listed in the ROD Amendment (chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene and 1,3,5-trichlorobenzene). Although there may be an increase in potential risk due to an increase in the CSF for benzene, this constituent has not been detected in groundwater outside the TI zone since April 2003.

Since the last five-year review, the oral RfD (for non-cancer outcomes) has remained the same for PCBs at 2.0 E-5 mg/kg/day and as of 2007 was available for benzene at 4 E-3 mg/kg/day. RfDs for additional ROD Amendment VOCs that were available in EPA's IRIS database were 2 E-2 mg/kg/day for chlorobenzene, 9 E-2 mg/kg/day for 1,2-dichlorobenzene, and 1 E-2 mg/kg/day for 1,2,4-trichlorobenzene. The RfDs for 1,3-dichlorobenzene, 1,4-dichlorobenzene, and 1,2,3-trichlorobenzene were not available in the IRIS database. The inhalation reference concentration (RfC) for 1,4-dichlorobenzene remained the same at 8.0 E-l mg/m3 and as of 2007 was available for benzene at 3.2 E-2 mg/m3. RfCs were not available in EPA's IRIS database for the other ROD Amendment VOCs or PCBs. Although the addition of RfDs and RfCs for benzene and other VOCs would increase the cumulative risk, benzene has not been detected outside the TI zone since April 2003, and concentrations of other VOCs detected outside the TI zone have been below the current MCLs and MEGs. Additionally, when assessing whether the OU-2 remedy has been completed, a final risk assessment will be performed that will include evaluation of the cumulative risk.

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.

Expected Progress Towards Meeting RAOs. A TI waiver has been granted for a small portion of the site groundwater. The TI Zone, about three acres in size, includes and surrounds the TWA II area, and includes the area where concentrations of VOCs (e.g., benzene, 1,4-dichlorobenzene)

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and PCBs exceed groundwater performance standards. Based on groundwater data, groundwater outside the TI zone has met 2002 ROD Amendment performance standards for VOCs since 2002 and for PCBs since April 2006.

7.2.3 OU-3: Riggs Brook

Changes in Standards and TBCs. Sediment quality criteria discussed in the first five-year review have not changed. This guidance for sediment continues to be included as a TBC in Appendix E. These criteria continue to be more conservative than the 1989 ROD target cleanup goal of 1 ppm. However, it was agreed by all parties prior to the 1989 ROD, including the USFWS that negative short-term impacts to the wetlands ecology outweighed the removal of sediments to that level. A trigger level of 5 ppm PCBs for further action was therefore established in the ROD that, 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 beyond the ingestion of fish. As described earlier, the threshold limit set in the 1989 ROD was met in the two biota sampling events. With PCBs cleanup levels being attained in the groundwater outside the TI zone since spring 2006, there is no indication that this pathway would become an unacceptable risk in the future.

Changes in Toxicity and Other Contaminant Characteristics. The major contaminant that has been historically detected in Riggs Brook sediments is PCBs. Since the last five-year review in 2002, the oral CSF for PCBs has decreased to 2 (mg/kg/day)-l. Therefore, the potential risk from exposure to PCBs would decrease. In addition, ten years of monitoring data show the overall concentrations of PCBs to be stable and not increasing.

Changes in Risk Assessment Methods. There have not been any changes in the risk assessment methods for sediment since 2002. Therefore the remedy remains protective.

Expected Progress Towards Meeting RAO. Ten years of sediment sampling in Riggs Brook have been completed. There have been periodic exceedances of the 5 ppm trigger level for PCBs in Riggs Brook sediment since sampling began in 1996. These exceedances appear to be the result of the variability of sediment deposition near the brook. The results of the 10-year sampling program show the sediments in Riggs Brook to be stable, with no indication that PCBs are migrating or increasing in concentration. Concentrations of PCBs in biota were below the threshold limit 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?

ANSWER C: NO.

7.3.1 OU-1: Source Control Remedial Action

The source control work was completed with the covering of the Designated Area where soils with less than 10 ppm PCBs were consolidated, the subsequent reestablishment of vegetation, and institutional controls that require that the soil cover be maintained. Continued O&M will ensure that the site soils are not accessible so there is no potential for human exposure. MEDEP expressed concern during the 2007 site inspection that one foot of clean fill above the Designated

32

Area soils may be insufficient to prevent burrowing animals from coming into contact with the consolidated soils, and suggested that the periodic soil sampling be conducted at a depth greater than the 4 - 8 inches previously recommended by MEDEP. No other information has been discovered that would call into question the protectiveness of the remedy for OU-1.

7.3.2 OU-2: Management of Migration

The main issue for OU-2 at the time of the 2002 five-year review was the possibility of a need for a TI waiver for a portion of the groundwater.. This waiver was subsequently part of the 2002 ROD Amendment. Ongoing monitoring of groundwater has shown that beyond the TI Zone VOCs have met the performance standards since the spring 2002 sampling event and PCBs since the spring 2006 sampling event. A decrease in concentrations has also been noted in the monitoring wells within the TI Zone and the amount of oil collected from TWA II wells has decreased such that active recovery is no longer being performed. No other information has been discovered that would call into question the protectiveness of the remedy for OU-2.

7.3.3 OU-3: Riggs Brook

The remedy selected for Riggs Brook consisted of the monitoring of contaminants in sediments and biota. There have been sporadic exceedances of clean-up goals for OU-3 (less than 5% of the sampling data, or one to two locations per year, have been above the trigger level); however, the annual mean PCS concentration since 2001 was 0.40 to 1.05 ppm with the target cleanup level being 1 ppm. The biota sampling has shown the PCB concentrations to be below the 2 ppm threshold level (in fact, the detected concentrations have been below 1 ppm). While this area is mapped as a Zone A flood hazard area, it has not been negatively affected by any flooding or other weather-related events since the last review. The April 25, 2007 site inspection came after two significant storm events earlier in April, and there was not any indication of storm-induced erosion. Further, the 2007 wetland monitoring report stated that the Riggs Brook wetlands did not appear to serve as a floodplain, given its location in the watershed. No other information has been discovered that would call into question the protectiveness of the remedy for OU-3.

7.4 TECHNICAL ASSESSMENT SUMMARY

According to the data reviewed, the site inspection, and the interviews, the remedy is functioning as intended by the 1989 ROD, as modified by the 1994 BSD and the 2002 ROD Amendment. There have been no significant changes to the physical conditions of the Site since the 2002 five-year review other than perhaps an increased level of vegetative growth. The response actions required for OU-1 has been completed and the samples taken for the soil cover in OU-1 were well below the cleanup level. ARARs for groundwater are being met outside the TI Zone, and institutional controls prevent exposure to contaminated groundwater in the TI Zone. The ten years of annual sediment sampling indicate the PCB concentrations are stable and the mean concentration for the final four years of sampling was below or just above the target cleanup level. There have been some changes in toxicity factors, a decrease in the CSF for PCBs, thereby lowering its risk, and an increase in the oral CSF for benzene. However, as benzene has not been detected in the groundwater outside the TI Zone since spring 2003, this change does not affect 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.

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7.4.1 OU-1: Source Control Remedial Action

The source control portion of the remedy 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. 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 relevant to source control have emerged. Although some toxicity values for contaminants onsite have changed, the changes would not affect the outcome of the original Endangerment Assessment since there would be no significant change in cancer risks at the Site. With the completion of this work, the remedial action objectives 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 for the groundwater outside the TI Zone. The Declaration of Restrictive Covenant prevents exposure to contaminated groundwater within the TI Zone. There have been no additional O&M costs beyond the original scope of work. There have not been any changes in groundwater standards since the 2002 ROD Amendment. Since none of the decision documents specify the duration that performance standards have to be maintained before the remedial action objectives are met, with the attainment of standards for VOCs since spring 2002 and for PCBs since spring 2006, it would now be appropriate for EPA to address this issue.

One new exposure pathway identified since the ROD is the indoor pathway that would potentially exist if buildings were constructed onsite. However, there are currently no plans for any on-site construction and all previously identified pathways remain valid. Additionally, the VOC concentrations in the shallow groundwater do not suggest a significant source of vapors.

There were some changes in toxicity data for site contaminants, however only the oral CSF for benzene indicates a slightly greater risk of cancer than previously determined. Since the benzene has not been detected in groundwater outside the TI Zone since spring 2003, this change does not affect the protectiveness, and 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. Sampling at 36 locations since the 2002 FYR has indicated one exceedance in 2002, none in 2003, and two each in 2004 and 2005. The extent of the exceedances was found therefore to be very limited within the wetland area and the conditions appear to be stable. 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 level, the annual mean PCB concentration was either below or just above the target cleanup level for the last four years of sampling. Additionally, as with the other OUs, the change in the CSF for PCBs would slightly lower the risk values for sediments, thereby not affecting the protectiveness of the remedy.

34

8.0 ISSUES

8.1 SOURCE CONTROL

As discussed previously, the remedial action for OU-1 was completed in 1997. Long-term maintenance of the soil cover continues and repairs to minor erosion features on the access road have been made consistent with the draft O&M Plan. Permanent markers outlining the boundary of the Designated Area have been installed. Sampling of the Designated Area soil cover coincident with the five-year reviews has begun.

Maine DEP has voiced two concerns relative to the soil cover. One, in order to demonstrate the thickness of the 12-inch soil cover, the soil samples should be collected at 8 - 12 inches below the ground surface rather than the previously agreed upon 4-8 inches. Two, as burrowing animals, such as woodchucks, can make tunnels more than 12 inches below ground surface, the O&M plan should be expanded to include a burrowing animal management plan. Both of these concerns can be addressed as EPA finalizes the O&M Plan.

8.2 MANAGEMENT OF MIGRATION

The groundwater in the TWA II area of the Site was impacted by residual oil and EPA determined that it was technically impracticable from an engineering perspective to attain federal and state drinking water standards for a limited portion of the Site within a reasonable timeframe. Consequently, EPA amended the 1989 ROD in 2002 and included a waiver for attaining drinking water standards for that area (approximately 3 acres in the 23-acre Site). In order to maintain the protectiveness of the remedy, the 2002 ROD required active and passive recovery of the residual oil, long-term monitoring, and recording of the Declaration of Restrictive Covenants in the Kennebec County Registry of Deeds. All three components have been implemented.

The Statement of Work, Appendix II to the March 2004 Amendment to the Consent Decree, stated that the necessity and conditions for continuation of the oil recovery would be addressed in this five-year review, and each subsequent five-year review period. As noted in Table 4, the amount of oil actively recovered annually in 2004 and 2006 has decreased to an amount that is comparable to that recovered using passive collection. Therefore, the operation of the active oil recovery will be suspended at this time, and will be reassessed in the next scheduled five-year review in 2012. Passive recovery will continue.

One issue for OU-2 was identified during the five-year review. None of the decision documents, the 1989 ROD, 1994 BSD, 1995 contingency remedy invocation, the 2002 ROD Amendment, or the 1992 Consent Decree or 2004 Amendment to the Consent Decree, specifies the criteria to be used to determine attainment of the groundwater cleanup goals. With the groundwater beyond the TI Zone meeting the VOCs cleanup levels (including those established in the 1989 ROD and those set in the 2002 ROD Amendment) since spring 2002 and the PCBs cleanup levels since spring 2006, EPA, with opportunity for review and comment by Maine DEP, should develop criteria to make this determination. As part of this determination, a final risk assessment of the

35

residual contamination will be performed. This risk assessment will include an evaluation of the cumulative risk from the multiple contaminants.

8.3 RIGGS BROOK

The ten years of annual sampling required in the 1989 have been completed. Over 95% of the samples were below the PCB action trigger level of 5 ppm; the annual mean varied between 0.38 to 1.93 ppm (three years greater than 1 ppm, seven years 1 ppm or less). With the anticipated continued attainment of PCB groundwater standards that started in the spring 2006, it is expected sediment conditions will remain stable.

It has been noted that the majority of PCB concentrations in the Riggs Brook sediments have been measured at sampling location 3018. Without this outlier, the annual mean would be lower. While this location was originally not in the Riggs Brook wetlands sampling program, the recent wetland delineation does confirm that it is located within the wetlands. Given the limited area, it may be more efficient to remove the sediment in this area (i.e., less than a cubic yard) rather than to continue to monitor it indefinitely.

36

9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS

Issue Recommendations/ Party Oversight Milestone Affects Follow-up Actions Responsible Agency Date Protectiveness?

(Y/N) Current Future

OU-1 Source Control Soil Change sampling Sampling depth to 8- 12" for the EPA EPA/State Dec 2007 N N Depth soil cover sampling

events O&M Update O&M Plan, Plan obtain agency CMP EPA/State Dec 2007 N N

approval OU-2 Management of Migration Criteria Develop criteria to forGW determine when GW EPA EPA/State In FY 2008 N N Cleanup Cleanup is completed Levels OU-3 Riggs Brook Location Determine approach to CMP EPA/State Dec 2007 N N 3018 address exceedances

37

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 through a clean soil cap that covers remaining contamination and institutional controls that have been placed on the Site. Finalizing the O&M plan will ensure that the OU-1 remedy will remain protective.

OU-2 : The remedy at OU-2 is because institutional controls are in place to prevent the use of contaminated groundwater within the TI zone. Outside the TI Zone, groundwater has met the target cleanup levels for VOCs since spring 2002 and since spring 2006 for PCBs and monitoring is continuing to occur to confirm that safe levels have been met.

OU-3: The remedy at OU-3 is protective of human health and the environment. Annual sampling of sediments for ten years has resulted in over 95% of the samples being below the action trigger level, and the annual mean PCB concentration has varied between 0.38 and 1.72 ppm. Results from the two biota sampling events were below the threshold level of 2 ppm for all samples, with the overall average being below 1 ppm. Site inspections have documented functioning habitat in both the uplands and wetlands. With the anticipated continued decrease in PCB concentrations in the discharging groundwater, the remedy is expected to remain protective of human health and the environment.

Because the remedial actions at all OUs are protective, the Site is protective of human health and the environment.

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11.0 NEXT RE VIEW

The third five-year review for the O'Connor Site will be conducted in 2012.

39

12.0 DOCUMENT REVIEW LIST & REFERENCES

Central Maine Power (CMP), 2004. Letter from Roy Koster, CMP to Terrence Connelly, USEPA Region 1 RE: O'Connor Company Superfund Site VER Operation 2004; October 7.

CMP, 2006. Letter from Roy Koster, CMP to Terrence Connelly, USEPA Region 1 RE: O'Connor Company Superfund Site 2005 Riggs Brook Sediment Monitoring Report; January 23.

CMP, 2006. Letter from Roy Koster, CMP to Terrence Connelly, USEPA Region 1 RE: O'Connor Company Superfund Site VER Operation 2006; September 8.

City of Augusta, ME, Land Use Ordinance.

Flood Insurance Rate Map, City of Augusta, Maine, Kennebec County, Community-Panel Number 230067 0011. June 15, 1994.

ICF - Clement, Inc., 1988. Endangerment Assessment for the O'Connor Site in Augusta, Maine, (Table 8-1).

Tetra Tech NUS, Inc., 2002. Five-Year Review Report, O'Connor Company Site, Augusta, Maine; September.

The Smart Associates, 2003. 2002 Wetland Construction Monitoring Report, O'Connor Company Site, Augusta, Maine; Prepared for U.S. Environmental Protection Agency; January.

USEPA, 1989. Record of Decision Summary; U.S. Environmental Protection Agency, Region 1, Boston, Massachusetts; September.

USEPA, 1991. Consent Decree - United States of America, Plaintiff v. Central Maine Power Company, Defendant; September 3.

USEPA, 1994. Declaration for the Explanation of Significant Differences, O'Connor Company Superfund Site, Augusta, Maine; July 11.

USEPA, 2001. Comprehensive Five-Year Review Guidance, USEPA 540-R-01-007; June.

USEPA, 2002. Record of Decision Amendment Operable Unit 2, F. O'Connor Company Superfund Site; September.

USEPA, 2002. OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance); November 29.

United States of America v. F. O'Connor Company Superfund Site, et. al, U.S. District Court for the District of Maine (Amendment to Consent Decree) (March 2004); Appendix II to Amendment to O'Connor Consent Decree Remedial Design/Remedial Action 2003 Statement of Work.

Woodard & Curran, 1996. Source Control Remedial Action Community Relations Plan, O'Connor Company Superfund Site, Augusta, Maine; July.

40

Woodard & Curran, 10/97. Final Riggs Brook Sediment and Biota Sampling and Analysis Plan, O'Connor Superfund Site, Augusta, Maine; October.

Woodard & Curran, 1998. 7997 Riggs Brook Sediment and Biota Monitoring Report, O'Connor Company Superfund Site, Augusta, Maine; February.

Woodard & Curran, 1998. Final Source Control Remedial Action Report, O'Connor Company Superfund Site, Augusta, Maine; September.

Woodard & Curran, 1999. 7995 Riggs Brook Sediment Sampling Report, O'Connor Company Superfund Site, Augusta, Maine; January.

Woodard & Curran, 2000. 7999 Riggs Brook Sediment Monitoring Report, O'Connor Company Superfund Site, Augusta, Maine; February.

Woodard & Curran, 2001. 2000 Riggs Brook Sediment and Biota Monitoring Report, O'Connor Company Superfund Site, Augusta, Maine; July.

Woodard & Curran, 2001. 2007 Riggs Brook Sediment Monitoring Report, O'Connor Company Superfund Site, Augusta, Maine; December.

Woodard & Curran, 2002. MOM Sampling and Analysis Semi-annual Report, April 2002, O'Connor Company Superfund Site, Augusta, Maine; June 10.

Woodard & Curran, 2002. Technical Impracticability Evaluation for OU-2 Management of Migration, O'Connor Company Superfund Site, Augusta, Maine. Prepared for Central Maine Power Company, Augusta, ME; June.

Woodard & Curran, 2002. MOM Sampling and Analysis Annual Report, September 2002, O'Connor Company Superfund Site, Augusta, Maine; October 30.

Woodard & Curran, 2002. 2002 Riggs Brook Sediment Monitoring Report, O'Connor Company Superfund Site, Augusta, Maine; October.

Woodard & Curran, 2003. MOM Sampling and Analysis Semi-annual Report, April 2003, O'Connor Company Superfiind Site, Augusta, Maine; June 26.

Woodard & Curran, 2003. MOM Sampling and Analysis Annual Report, September 2003, O'Connor Company Superfund Site, Augusta, Maine; December 2.

Woodard & Curran, 2003. 2003 Riggs Brook Sediment Monitoring Report, O'Connor Company Superfund Site, Augusta, Maine; December.

41

AGREEMENT. RELEASE AND STTPTTT ATTCW

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 ground-water 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, FCBs 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 al. v. Central Maine Power Company; Civil Action No. 92-0302-B. Pursuant to mis 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, FCBs and cPAHs at the Site are set forth in the Record o£ Decision fROD**) issued by EPA. EPA proposes to adjust certain cleanup levels in a document identified as the Explanation of Significant Difference (ESD).

"> " •» • t -: . ... . . ;. ; ,• _ .. ..

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 reach-this cleanup level for PCBs in the less contaminated soils on site, information which came to light after the ROD was initially

-2- . '

approved indicates that it will neither be technically feasible nor cost effective to achieve the one ppm cleanup level vising 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-pprn 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 will 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 dean soiTfrom off site sources, to the thickness of 12 inches as specified in the BSD. The Department agrees that a soil cover 1? inches or greater meets the Department's risk criteria of 3 Or5 provided that the cover Is . maintained. ' . •

6. Pursuant to the Consent Decree, following Site inspection and submission of a written report signed by the GIMP'S 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 groundwaler under 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 Lav/, 38 M.ILS.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 ($125,000.00) in full

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compensation for the natural resource damages described above. Payment shall be made bv 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.

r V

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. •

PEClARATTONf OF RESTRTrTTVE COVENANT

THE STATE OF MAINE ) , ) KNOW ALL MEN BY THESE PRESENTS THAT­

COUNTY 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 v. 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 RobertJL 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 portiorf 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 groundwatar 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-contavued compliancewith-all applicable cleanup standards prescribed in, and to ensure the ongoing adequacy of the

= -09

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 created, hereby 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 party shall benefit from the restriction contained herein or have any right or standing to enforce same. :

i 6. By its execution hereof/ DEP acknowledges and agrees that it has reviewed

and approved of the 'matters contained herein and that mis 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 aru?

correct and based upon his/her personal knowledge.

NOTARY PUBLIC

D.E.P.

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ACKNOWLEDGED AND AGREED TO. /

DEPARTMENT OF ENVIRONMENTAL PJROTECnON

Name: . Title:

STATE OF MAINE KENNEBEC, ss.

Personally appeared before me this 'day of AprQ, 1994, toe above-named and made oath that the foregoing Is true and correct

and based upon his/her personal knowledge.

NOTARY FUBIIC

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 cover all 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 -?/,<3-£? day of June, 1994 the above-named Alan M. Prysunka, and made oath that the foregoing is true and correct and based upon his personal knowledge.

NOTARY PUBLIC

D.E.P. 25-7 7825 P. 37

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CENTRAL MAINE POWER COMPANY

" DATED: June 8, Gerald C. Poulin Vice President, Generacion and Technical Support

STATE OP MAINE KENNEBEC, ss.

Personally appeared before me this ^^ day of April, 1994 the above-named Gerald C. Poulln , and made oath that the foregoing is true and correct and based upon his personal knowledge.

NOX/iRY PUBLIC

KARLAE.SWISEV Notary PuWte. M«in«

My Commtotan fc Irw April 1,2001

ATTACH: JEST 2

"•'.- DEED DESCRIPTION

The following described parcel, situated on the Northeasterly sideof State Route 17, locally known as Eastern Avenue, in the City ofAugusta, Kennebec County, particularly bounded and described asfollows:

Beginning at a 1" iron pipe found at an angle point in theNortheasterly sideline of Eastern Avenue (Bk 4089-p. 269), asshown on a plan entitled, "standard Boundary survey forCentral Maine Power Company, F. O'Connor Superfund Site" byCoffin Engineering, Revision dated March 22, 1994. said pointof beginning is also situated S 47«24'45" E of and 52.78 feetfrom a 3/4" iron pipe found at the most Southerly corner ofHenry R. & Lillian W. Cox (Bk 1554-p. 126).

Thence N 47°42'O3" E a distance of 623.68 feet to a 5/8" rebarset in a stone wall in the Southwesterly line of Lionel J, &Raymond A. Rodrigue (Bk 2857-p.34). Said rebar is alsosituated S 60»26'23" E of and 251.05 feet from a 5/8" rebarset- 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 setat the Northwesterly sideline of a 100 foot wide transmissionline corridor designated Section #19 (Bk 1117-p. 314) . Thetie line between the two last mentioned rebars is S 6O046'07"E and 1,354.72 feet.

Thence S 35°12"18"'W along the Northwesterly line of saidtransmission corridor, a distance of 386.82 feet to a 5/8"rebar set.

Thence S 79«45'02" W along the Northerly line ".of saidtransmission corridor, a distance of 824.70 feet to a 5/8"rebar set in the Northeasterly sideline of Eastern Avenue.

Thence N 40°50I03" W along the Northeasterly side of EasternAvenue, a distance of 822.31 feet to a 5/8" rebar set at themost Southerly corner of land conveyed from Jean E. & RobertL. Hussey to Central Maine Power Company (Bk 3507-p. 195).

Thence continuing N 40"50'03" along the Northeasterly side ofEastern Avenue, a distance of 109.00 feet back to the point ofbeginning.

Meaning and intending to describe 23.36 acres of land, asshown on a plan "entitled, "Standard Boundary Survey for

Central Maine Power Company F. O'Connor Superfund site" byCoffin Engineering & Surveying, revision dated March 22, 1994.

All directions are Magnetic 1987, based on a survey entitled,"Proposed Sale to Augusta Water District" by CoffinEngineering & Surveying, dated November 9, 1987.

Reserving an easement granted to the State of Maine, recordedin the Kennebec County Registry of Deeds in Book 3343-p. 221.

Excepting the old Field burial ground which contains about oneeighth of an acre.

The herein described parcel is a portion of land conveyed fromF. O'Connor Co. to Central Maine Power Co., recorded in theKennebec County Registry of Deeds in Book 4089-p. 269, ahclalso a portion of land conveyed from Jean E. 6 Robert L.Hussey to said CMPCo. ,- recorded in Book 35O7-p. 195.

X:\lHR\DEEODES.CftM

LCSOC

-.—^»w»TKHSBnWIPTl«^ " CENTRAL MAINE POHER CO, CONSERVATION EASEMENT

items at ,.:<& EASTERN AVENUE *?*. . AUGUSTA. MAINE

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•730-41-4

APPENDIX B

F. O'CONNOR SITE SECOND FIVE-YEAR REVIEW

SOIL SAMPLING DATA AND QA/QC SUMMARY

Appendix B

INTRODUCTION

In conjunction with the Five Year Site Review and the 2003 Statement of Work (SOW), soil sampling was conducted by Woodard & Curran on April 24, 2007 at the O'Connor Superfund Site (the Site). The objective of the soil sampling program was to determine the integrity of the soil cover on the designated area (DA). As established in the 1994 ESD, the DA is a portion of the Site that was used to consolidate soil and sediment containing levels of polychlorinated biphenyls (PCBs) and/or carcinogenic polyaromatic hydrocarbons (cPAHs), between one and ten ppm during the Source Control Remedial Action (SCRA). As stated in the September 1998Final SCRA Report, following the regrading of the site with clean backfill (containing less than or equal to 1 part per million (ppm) PCBs, 1 ppm cPAHs and 248 ppm lead), the DA was covered with an additional 12 inches of clean fill. In accordance with the 2003 SOW, the boundaries of the DA were modified as shown in the attached revised Site Plan.

Sample collection and analytical techniques followed the specifications contained in the Quality Assurance Project Plan (QAPP) Amendment submitted to the Environmental Protection Agency (EPA) and the Maine Department of Environmental Protection (DEP)on April 17, 2007. The following sections describe the activities and results associated with this soil sampling event.

SAMPLE POINT SELECTION AND SITE SURVEY

Prior to traveling to the Site, an Excel random number generator was used to select 10 sampling locations from a total of 183 grid points that fall within the DA and within the area where cover soil was applied in 1997. The sample points and the associated coordinates are included in Table 1 below.

Table 1 O'Connor Superfund Site

Sample Locations - April 2007 Soil Sampling

Sample Locations Northing Coordinate Easting Coordinate 1009.07 536417 3064918 1036.07 536297 3064888 1070.07 536177 3064978 1071.07 536177 3065008 1083.70 536147 3064948 1095.07 536117 3064858 1114.07 536057 3064618 1118.07 536057 3064738 1121.07 536027 3064618 1178.07 536072 3064633

A digital global positioning system (DGPS) unit was used to locate each of the sample points prior to collection. Pin flags were placed into the ground to mark sample point locations. The sample point locations are shown in Figure 1 and in the Revised Site Plan.

SAMPLE COLLECTION METHODS

After the sample points were located and marked, soil samples were collected in accordance with Woodard & Curran Standard Operating Procedures SOP S-8/S-9. A hand auger was used to get through the top layer of vegetation to a target depth of 4 to 8 inches below ground surface. Once the target depth was reached, a stainless steel spoon was used to collect soil. Using the same procedure additional soil was collected at the same depth from four points located within six inches of the original sample location. The soil from all points around the sample location was placed in a mixing bowl and thoroughly homogenized using a stainless steel spoon to create one composite sample. From the homogenized soil, a portion was used to fill a labeled four ounce glass soil jar. A composite soil sample was collected for each of the locations resulting in a total of ten samples. All samples were stored on ice in a cooler immediately following sample collection. After sample collection at each sample point, the hand auger, bowls and spoons were decontaminated with soap and deionized water to prevent the potential transfer of PCBs between sample locations.

ANALYTICAL METHODS

All of the soils samples were analyzed for PCBs using EPA Method 8082. The following Aroclors were identified during sample analysis: 1016,1221,1232,1242,1248,1254 and 1260. A method detection limit of approximately 0.017 milligrams/kilogram (mg/kg) per Arochlor was used to ensure consistency with data quality objectives and historical reporting limits. A determination of percent solids was used to adjust raw sample concentrations to dry weight values. All analyses were performed by Katahdin Analytical Services of Scarborough, Maine.

SAMPLE RESULTS

PCBs were not detected in 6 of 10 (60%) soil samples. Trace concentrations of PCBs ranging from 0.023 mg/kg to 0.18 mg/kg were detected in 1009.07, 1036.07, 1121.07 and 1118.07. The dry weight sample results are summarized in Table 2.

Table 2 O'Connor Superfund Site

Summary PCB Results Soil Sampling - April 2007

Sample Location Total PCBs (mg/kg) 1009.07 0.032 1036.07 0.18 1070.07 ND 1071.07 NO 1083.70 ND 1095.07 ND 1114.07 ND 1118.07 0.032

1121.07/Duplicate 0.023/0.028 1178.07 ND

ND = not detected

As indicated in Table 2, all of the PCB detections are below the action level of 1 mg/kg, confirming the effectiveness and integrity of the landfill cover applied in 1997. All of the detections were identified as Arochlor 1260. Percent solids values for the soils ranged from 76 to 86%.

DATA QUALITY CONTROL RESULTS

Quality control samples were reviewed to ensure that the data are of a quality sufficient to meet the data objective for site characterization. Data validation was performed at a Tier II level which includes a review of the tabulated quality control results. Overall the quality control results are acceptable. There were no qualifiers added to any of the soil sample results to indicate estimated or false positive concentrations.

Extractions and analyses of the soil samples were completed within the required holding times. Surrogate recoveries were within specifications for all samples indicating that the instrumentation was functioning properly during sample analysis. A field duplicate sample was collected at sample point 1121.07 to determine the variability of the PCB concentrations at one location. Concentrations of PCBs were detected at 0.023 and 0.028 mg/kg for the sample and duplicate, respectively. The EPA criterion for compliant field duplicate soils results that compare well with the associated sample is a relative percent difference of 50% or less. The RPD between sample and duplicate concentrations of 1121.07 was calculated to be 19%. The field duplicate results indicate that PCB concentrations within the soil matrix are relatively homogeneous and that the level of precision is acceptable.

A matrix spike sample was collected at sample point 1071.07 to identify potential biases and to determine levels of precision and accuracy. Recoveries of Arochlor 1016 and 1260 were acceptable indicating that matrix interferences are not likely present in the soil media and that the precision and accuracy demonstrated by the results are acceptable.

An equipment blank, EB-100.07 was collected by pouring deionized water across the end of the hand auger, a spoon and finally into one of the stainless steel bowls used for homogenizing the sample. From the bowl, the water was then poured into a one liter glass sample bottle. The blank was analyzed for PCBs to determine the potential for carry over concentrations from one sample location to the next. PCBs were not detected in the equipment blank, indicating that the reported sample concentrations are representative of conditions at the Site.

Laboratory control samples were analyzed to determine analytical accuracy. The recoveries of PCBs in the analyses of the laboratory control samples were acceptable indicating that sample concentrations were accurately quantified.

The quality control results were satisfactory and within criteria for all parameters. As a result, data qualifiers were not added to any sample results. The quality of the data was sufficient to meet the project objective of characterizing conditions at the O'Connor Site.

125 250 soo CMP Sampling Event 4-24-07 Figure 1

APPENDIX C

F. O'CONNOR SITE SECOND FIVE-YEAR REVIEW

RIGGS BROOK SEDIMENT DATA (1996 - 2005)

••

Appendix C

O'Connor Site - Riggs Brook Sediment Sampling PCBs mg/kg

No. Location 1996 198? 1998 1999 2000 2001 2002 2003 2004 2005 >5ppm Comments

1 8001 upgradient location

2 8002/8002A upgradient location

3 8002B ;;• ... •:• sir .. jj,f Bsiiflia upgradient location; added 1997 at biota location

4 8003 0.097

5 8004 2.8 29 •:..: :?•. | :,> 8.2 0.055 2of 9

6 8005 0.024

7 8006 0.77 3.2 16.45 14 10.4 0.73 2.9 0.94 0.59 2.45 3 of 10

8 8007 0.24 2.5 1.2 0.14 0.98 0.378 0.562 0.75 0.48 1.3

9 8008 0.047 0.125 0.034 0.035 0.017

10 8009 0.279 0.93 0.34 0.154 1.1 0.13 0.306 0.2 0.22 0.28

11 8010 0.11

12 8011 0.044 0.039 0.053 0.0553

13 8012 0.132 0.34 0.53 0.154 0.178 0.11 0.57 0.09

14 8013 0.47 5.7 1 |p| ^ p ||| 0.052 1 of 9

15 8014 0.068 0.039 0.43 1.5 0.238 0.206 0.17 0.43 0.12

16 8015

17 8016 0.071 0.031 0.026

18 8017 0.67 0.057 0.096

19 8018 0.3 0.2 0.034 0.063

20 8019 0.029 0.247 0.276 0.49 0.394 0.037 0.13

21 8020 0.059 0.234 0.077 0.021 0.099

22 8021 0.082 0.032 0.13

23 8022 0.041 0.048 0.053

24 8023 0.05

25 3018 0.1 H 1 «.;;.-S:V: 6.4 3.9 4.6 6.1 5.63 4.4 18 8 5 of 9 mistaken for 8004 in 1998; part of Area 3 of Source Control; added 1999 .. ;; ......... ; .......

26 8039 ::'.:.r\Hr :"-. :-\: 0.029 0.088 0.069 mistaken for 801 3 in 1998; added 1999

27 9A925 S?*KIlii ;;...:;"•;; . V. : : ."•:v.!:L ?-54* I 0.086 0.65 0.67 0.68 1.2 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

28 9B925 ";:'•:-; :; Vk;..:.:N';::: 0.279 0.135 0.21 0.27 0.5 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

29 9BOOO . ': ' ' ' ; ". .-- ! 12.6 0.65 0.9 2.1 1.4 4 1 Of6 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

30 9C925 0.68 2.32 0.77 0.3 1.9 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

31 9COOO 2.05 0.32 1.91 0.6 0.79 0.32 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

32 9C025 1.99 0.035 0.76 0.49 0.058 1.7 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

33 9C050 7.3 0.39 1.44 0.35 0.59 4 1of6 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

34 9C075 11.2 2.32 1.94 0.78 0.2 0.57 1 of 6 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

35 9C100 3.8 0.47 1.13 1.1 2.1 7 1 Of6 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

36 9C125 5.5 0.51 0.75 1 0.63 3.4 1 of6 part of 51 node grid sampled in 2000 to ID pathways to 8006; added 2002

No. samples 23 26 36 36 36

blank PCBs not detected Not sampled Sampled as part of separate program

APPENDIX D

F. O'CONNOR SITE SECOND FIVE-YEAR REVIEW

SITE INSPECTION REPORTS AND PHOTOGRAPHS

D-l: EPA SITE INSPECTION CHECKLIST D-2: O'CONNOR COMPANY SITE INSPECTION (W&C)

APPENDIX D-l

Five-Year Review Site Inspection Checklist

I. SITE INFORMATION

Site name: F. O'Connor Company Superfund Site Date of inspection: April 25, 2007

Location and Region: Augusta, Maine/ Region 1 EPA ID: MED980731475

Agency, office, or company leading the five-year Weather/temperature: Sunny, westerly wind, upper review: USEPA, Region 1 50s

Remedy Includes: (Check all that apply) D Landfill cover/containment D Monitored natural attenuation Q Access controls D Groundwater containment X Institutional controls D Vertical barrier walls D Groundwater pump and treatment Q Surface water collection and treatment X Other Soil excavation and off-site disposal: active and passive oil recovery: groundwater. sediment. and biota monitoring, and TI waiver

Attachments: D Inspection team roster attached D Site map attached

II. INTERVIEWS (Check all that apply)

1. O&M site manager Roy Koster Sr Environmental Specialist April 25. 2007 Name Title Date

Interviewed X at site D at office D by phone Phone no. Problems, suggestions; D Report attached

2. O&M staff Name Title Date

Interviewed D at site D at office D by phone Phone no. Problems, suggestions; D Report attached

3. Local regulatory authorities and response agencies (i.e., State and Tribal offices, emergency response office, police department, office of public health or environmental health, zoning office, recorder of deeds, or other city and county offices, etc.) Fill in all that apply.

Agency City of Augusta Code Enforcement Office Contact George Soucv Code Enforcement Officer Aue 1.2007 207.626.2366

Name Title Date Phone no. Problems; suggestions; D Report attached

Agency Lithglow Public Library, Augusta Contact Betsy Pohl Reference Librarian April 25. 2007 207.626.241

Name Title Date Phone no. Problems; suggestions; D Report attached

4. Other interviews (optional) X Report attached.

Lori Moreau, Woodard & Curran, Inc, Consultant for Central Maine Power

III. ON-SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)

O&M Documents DO&M manual D Readily available D Up to date XN/A D As-built drawings D Readily available D Up to date X N/A D Maintenance logs D Readily available D Up to date X N/A Remarks CMP maintains maintenance logs/site inspection logs at their office, about ten minutes from the Site. With no ongoing site activities and no trailer/building onsite. no records are kept on the Site.

Site-Specific Health and Safety Plan D Readily available D Up to date XN/A D Contingency plan/emergency response plan D Readily available D Up to date XN/ A Remarks

3. O&M and OSHA Training Records D Readily available D Up to date X N/A Remarks

Permits and Service Agreements D Air discharge permit D Readily available D Up to date XN/ A D Effluent discharge D Readily available D Up to date XN/ A D Waste disposal, POTW D Readily available D Up to date XN/ A D Other permits D Readily available D Up to date XN/A Remarks

Gas Generation Records D Readily available D Up to date X N/A Remarks

Settlement Monument Records D Readily available D Up to date X N/A Remarks

7. Groundwater Monitoring Records X Readily available D Up to date D N/A Remarks

8. Leachate Extraction Records D Readily available D Up to date X N/A Remarks

9. Discharge Compliance Records D Air D Readily available D Up to date X N/A D Water (effluent) D Readily available D Up to date X N/A Remarks

10. Daily Access/Security Logs D Readily available D Up to date X N/A Remarks

2

IV. O&M COSTS

O&M Organization D State in-house D Contractor for State X PRP in-house X Contractor for PRP D Federal Facility in-house D Contractor for Federal Facility D Other

O&M Cost Records D Readily available D Up to date D Funding mechanism/agreement in place Original O&M cost estimate: For OU-1. $ 15.000 year 1; $3.00 for subsequent years. No estimates for

OU-2 and OU-3 because there have been no O&M costs associated with them

D Breakdown attached

3. Unanticipated or Unusually High O&M Costs During Review Period Describe costs and reasons: O&M costs have been less than estimated

V. ACCESS AND INSTITUTIONAL CONTROLS X Applicable D N/A

A. Fencing

1. Fencing damaged D Location shown on site map D Gates secured ,X N/A Remarks: There is a vehicle gate across the access road, about 100 feet from Route 17. and this locked. The fence was removed in 1997 after a public event with EPA Region 1 RA and MEDEP Commissioner pushing over the first section of the fence.

B. Other Access Restrictions

1. Signs and other security measures D Location shown on site map D N/A Remarks: There are "No Trespassing" signs posted along Route 17. However, the vegetation is so thick that these signs are not readily visible.

C. Institutional Controls (ICs)

1. Implementation and enforcement Site conditions imply ICs not properly implemented D Yes X No D N/A Site conditions imply ICs not being fully enforced D Yes X No D N/A

Type of monitoring (e.g., self-reporting, drive by) CMP personnel or their contractor visit quarterly for passive transformer oil recovery, twice a year for groundwater monitoring, and after each major storm event Frequency Responsible party/agency CMP Contact: Roy Koster

Name Title Date Phone no.

Reporting is up-to-date X Yes D No D N/A Reports are verified by the lead agency (and support agency, MEDEP) X Yes D No D N/A Specific requirements in deed or decision documents have been met X Yes D No D N/A Violations have been reported D Yes D No X N/A Other problems or suggestions: D Report attached

2. Adequacy X ICs are adequate D ICs are inadequate D N/A Remarks: The entire Site is part of a property that is wholly owned by CMP. The environmental restrictions placed on the deed require CMP to get written approval from MEDEP before undertaking any activity that might affect the remedy. As part of the remedy, the Designated Area has been identified onsite by the placement of markers at each of the ten turning points of the Designated Area perimeter.

D. General

1. Vandalism/trespassing D Location shown on site map X No vandalism evident Remarks

2. Land use changes on site X N/A Remarks

3. Land use changes off site D N/A Remarks: In the five years since the last review, there has been no change in land use along Route 17 from the intersection with Cony Road, quarter-mile west of the Site, to the surface water divide a mile to the east. There have been a few new homes and two commercial buildings on Conv Road to the west. Municipal water and sewer are available along this section of Cony Road.

VI. GENERAL SITE CONDITIONS

A. Roads X Applicable D N/A

1. Roads damaged D Location shown on site map D Roads adequate D N/A Remarks: There were low spots at the access road entrance that were to be filled in.

B. Other Site Conditions

Remarks

VH. LANDFILL COVERS D Applicable X N/A*

* Although there is no landfill on this Site, part of the remedy included a twelve-inch soil cover over a 3-4 acre portion of it that is called the "Designated Area", and as such, some of the items below are relevant to the remedy.

A. Landfill Surface

1. Settlement (Low spots) D Location shown on site map X Settlement not evident Areal extent Depth Remarks

2. Cracks D Location shown on site map X Cracking not evident Lengths Widths Depths Remarks

3. Erosion D Location shown on site map X Erosion not evident Areal extent Depth Remarks

4. Holes D Location shown on site map X Holes not evident Areal extent Depth Remarks

5. Vegetative Cover X Grass X Cover properly established X No signs of stress D Trees/Shrubs (indicate size and locations on a diagram) Remarks

6. Alternative Cover (armored rock, concrete, etc.) X N/A Remarks

7. Bulges D Location shown on site map X Bulges not evident Areal extent Height Remarks

Wet Areas/Water Damage D Wet areas/water damage not evident X Wet areas X Locations shown on site map Areal extent_ D Ponding D Location shown on site map Areal extent_ D Seeps D Location shown on site map Areal extent_ D Soft subgrade D Location shown on site map Areal extent

Remarks: There are three created wetlands onsite dating back to the 1970s. The westernmost one was created when soils excavated for the creation of the other two wetlands (upper and lower lagoons) was placed in an upland area of the site, effectively damming surface water drainage. The two lagoons were originally required by MEDEP as sediment retention ponds, and were restored to wetlands post-source control activities. The last wetland monitoring report indicated that they are dominated by wetland species consistenmt with natural communities and provide function and value habitat.

9. Slope Instability D Slides D Location shown on site map X No evidence of slope instability Areal extent Remarks

B. Benches D Applicable X N/A (Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt the slope in order to slow down the velocity of surface runoff and intercept and convey the runoff to a lined channel.)

C. Letdown Channels X Applicable D N/A (Channel lined with erosion control mats, riprap, grout bags, or gabions that descend down the steep side slope of the cover and will allow the runoff water collected by the benches to move off of the landfill cover without creating erosion gullies.)

1. Settlement D Location shown on site map X No evidence of settlement Areal extent Depth Remarks

2. Material Degradation D Location shown on site map X No evidence of degradation Material type Areal extent

Remarks: A small area of geotextile was visible in the outfall channel from the lower lagoon, indicating that the riprap had been moved (presumably by water)

3. Erosion D Location shown on site map X No evidence of erosion Areal extent Depth Remarks

4. Undercutting Q Location shown on site map X No evidence of undercutting Areal extent Depth Remarks

5. Obstructions Type X No obstructions D Location shown on site map Areal extent Size Remarks

6. Excessive Vegetative Growth Type X No evidence of excessive growth D Vegetation in channels does not obstruct flow D Location shown on site map Areal extent Remarks

D. Cover Penetrations X Applicable D N/A

3. Monitoring Wells (within surface area of landfill) D Properly secured/locked D Functioning D Routinely sampled X Good condition D Evidence of leakage at penetration D Needs Maintenance D N/A Remarks

E. Gas Collection and Treatment D Applicable XN/ A

F. Cover Drainage Layer X Applicable D N/A

1. Outlet Pipes Inspected X Functioning D N/A Remarks

2. Outlet Rock Inspected X Functioning D N/A Remarks

G. Detention/Sedimentation Ponds D Applicable D N/A

1. Siltation Areal extent Depth D N/A D Siltation not evident Remarks: Lower Lagoon remains open water as designed, though the pervious channel material of the riprap channels limits the amount of surface water flow into the lagoons.

2. Erosion Areal extent Depth X Erosion not evident Remarks

3. Outlet Works D Functioning XN/A Remarks

4. Dam D Functioning X N/A Remarks

H. Retaining Walls D Applicable X N/A

I. Perimeter Ditches/Off-Site Discharge D Applicable XN/A

VHI. VERTICAL BARRIER WALLS D Applicable XN/A

IX. GROUNDWATER/SURFACE WATER REMEDIES X Applicable D N/A

A. Groundwater Extraction Wells, Pumps, and Pipelines D Applicable X N/A

B. Surface Water Collection Structures, Pumps, and Pipelines D Applicable X N/A

C. Treatment System D Applicable X N/A

Remarks: Vacuum enhanced system for recovery of separate phase transformer oil was terminated after 2006 annual recovery event. Equipment was cleaned and removed from the Site: semi-truck trailer that was used to store the equipment onsite has also been removed.

1. Monitoring Wells (pump and treatment remedy) D Properly secured/locked D Functioning X Routinely sampled D Good condition D All required wells located D Needs Maintenance D N/A Remarks: Casing of one well in the Tl Zone has been damaged that prevents purging.

D. Monitoring Data 1. Monitoring Data

X Is routinely submitted on time X Is of acceptable quality

2. Monitoring data suggests: X Groundwater plume is effectively contained X Contaminant concentrations are declining

D. Monitored Natural Attenuation

Monitoring Wells (natural attenuation remedy) D Properly secured/locked D Functioning D Routinely sampled D Good condition D All required wells located D Needs Maintenance X N/A Remarks

X. OTHER REMEDIES

If there are remedies applied at the site which are not covered above, attach an inspection sheet describing the physical nature and condition of any facility associated with the remedy. An example would be soil vapor extraction.

XI. OVERALL OBSERVATIONS

A. Implementation of the Remedy

Describe issues and observations relating to whether the remedy is effective and functioning as designed. Begin with a brief statement of what the remedy is to accomplish (i.e., to contain contaminant plume, minimize infiltration and gas emission, etc.).

Remedy is protective and is functioning as designed. Source Control successfully met soil cleanup standards; recent sampling of the soil cover plus visual inspections support the conclusion that the source control component remains protective. Downgradient of the TI Zone, groundwater is meeting standards. Ten years of monitoring of Riegs Brook Sediments indicates that the remedy is protective with biota data below the threshold levels and over 95% of sediment samples below the trigger level and the annual mean at or below the cleanup level for the past four years.

B. Adequacy of O&M

Describe issues and observations related to the implementation and scope of O&M procedures. In particular, discuss their relationship to the current and long-term protectiveness of the remedy.

Observations indicate that only minimal maintenance is needed for the source control component. Ten years after the completion of the source control activities, vegetation is well established over the Site and there has only been minimal erosion of the road surface. With no further active remediation anticipated at the Site, long-term maintenance needs are expected to remain minimal.

C. Early Indicators of Potential Remedy Problems

Describe issues and observations such as unexpected changes in the cost or scope of O&M or a high frequency of unscheduled repairs, that suggest that the protectiveness of the remedy may be compromised in the future.

No indications of potential remedy problems were observed during the site inspection for this five-year review: nor during the regularly scheduled inspections.

D. Opportunities for Optimization

Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.

During the period when EPA and MEDEP are developing the criteria to determine whether the management of migration component. OU-2. is complete, the frequency of sampling could be reduced.

O'Connor Company Site Inspection - April 25,2007

Attendees:

Terry Connelly - EPA, Remedial Project Manager Claudia Salt - MEDEP, Project Manager Roy Koster - Central Maine Power, Senior Environmental Specialist Lori Moreau - Woodard & Curran - Project Engineer

The Site Inspection began at approximately 9:15 AM and concluded at approximately 11:30 AM. The weather was sunny and approximately 55 degrees. Observations made by EPA and MEDEP are noted below.

Field Notes:

The vegetation is well established, and no bushes or shrubs are growing within the Designated Area of the Site. Roy Koster stated that CMP mows the top grassy portion of the site annually.

Water was observed in the upland marsh, the upper lagoon and the lower lagoon. Drainage channels appear to be in good condition, and functioning as designed. A small amount of soil appeared to be eroded from the base of the rip rap running from the upper lagoon to the lower lagoon, but the rip rap and the vegetated slope are intact. This eroded soil is likely the result of the rain storm event during the week of April 16, 2007, in which approximately 3 inches of rain fell on the Augusta area. A small (3-4 inch) poplar tree was observed to be growing at the base of this rip rap. A small amount of woven geotextile was observed to be exposed below the culvert from the lower lagoon, where the rip rap had been pushed away.

The ten survey markers (A-J) that serve as the boundaries of the Designated Area were clearly visible.

Monitoring wells were easy to locate since they have high stick ups. Monitoring well MW-101A was observed to have risen up approximately one foot due to frost heave. The sampling crew was unable to get a water level, but successfully sampled the well. Monitoring well OW-209A was also observed to have risen due to frost heave approximately six inches.

The dirt access road is in good repair. One small low area was observed near Route 17 along the edge of the Designated Area between boundary markers A and B.

There is currently a CMP trailer on the Site that was used during operation of the Vacuum Enhance Extraction. According to CMP, this trailer has been decontaminated and will be removed from the site.

EPA stated that they will be sending out a letter to area residents to let them know that we are in the five-year review process, to see if anyone has any comments or concerns.

APPENDIX E-l: IDENTIFICATION OF CHEMICAL-SPECIFIC ARARS

REQUIREMENT REQUIREMENT SYNOPSIS

» GROUNDWATERFederal Regulatory Requirements

SOWA - Section 1412 -MCLs (40 CFR 141.11-141.6)

SDWA- Section 1412 -MCLGs (40 CFR 141.50-141.51)

CWA - Section 304(a)

AWQC

USEPA Risk Reference Doses (RfDs)

US EPA Carcinogen Assessment Group Carcinogenic Potency Factors (CPFs)

Relevant and Appropriate

Relevant and Appropriate

Relevant and Appropriate

To be considered

To be considered

\

MCLs have been promulgated for several common organic and inorganic contaminants. These levels regulate the concentration of contaminants in public drinking water supplies, but may also be considered relevant and appropriate for groundwater aquifers used for drinking water. MCLGs are health-based criteria established for a number of organic and inorganic contaminants as water quality goals for drinking water supplies. These goals may also be considered relevant and appropriate for groundwater aquifers used for drinking water. Federal AWQC include (1) health-based criteria developed for 95 carcinogenic and noncarcinogenic compounds and (2) other water quality parameters protective offish and aquatic life. AWQC for the protection of human health provide levels for exposure from drinking water and consuming aquatic organisms, and from consuming fish alone. Remedial actions involving contaminated surface water or groundwater must consider the uses of the water and the circumstances of the release or threatened release; this determines whether AWQC are relevant and appropriate. RfDs are considered the levels unlikely to cause significant adverse health effects associated with a threshold mechanism of action in human exposure for a lifetime. Carcinogenic effects present the most up-to-date information on cancer risk

jiotency derived from USEPA's Carcinogen Assessment Group.

1

USEPA Health Advisories (HAs) To be considered HAs are issued as non-regulatory guidance. HA values represent the concentration of contaminants in drinking water at which adverse health effects would not be expected to occur. HAs are established for one-day and ten-day exposure durations.

U.S. Environmental Protection Agency To be considered RfDs are an estimate of a daily exposure concentration that is likely to be (USEPA) Risk Reference Doses (RfDs) without appreciable risk of deleterious effects during a lifetime exposure.

State of Maine Regulatory Requirements

Maine Standards for Classification of Applicable Groundwater is classified under the Maine Standards. The groundwater at the Groundwater (38 M.R.S.A., Chapter 3, O'Connor Site is classified as GW-A (i.e., water shall be of such quality that it Section 470) can be used for domestic purposes.

Maine Drinking Water Rules (10-144A Relevant and Maine's Primary Drinking Water Standards are equivalent to federal MCLs. CMR Chapters 231-233) Appropriate

1992

Maine Maximum Exposure Guidelines Relevant and MEGs are the Bureau of Health's recommendations for concentrations of (MEGs) Appropriate chemical contaminants in drinking water. MEGs are health-based guidelines

and are not legally enforceable.

2000

Maine Maximum Exposure Guidelines To be considered MEGs are the Bureau of Health's most recent recommendations for

(MEGs) concentrations of chemical contaminants in drinking water. MEGs are health-based guidelines and are not legally enforceable.

APPENDIX E-2: IDENTIFICATION OF ACTION-SPECIFIC ARARS

REQUIREMENT

GROUNDWATER Federal Regulatory Requirements

TSCA (15 USC §§ 2601-2692) and Polychlorinated Biphenyls (PCBs) Regulations (40 CFR 761: Subpart G, PCB Cleanup Policy; and Subpart C and D, Markings, Storage and Disposal) U.S. Department of Transportation Rules for Transportation of Hazardous Materials (49 C.F.R. Parts 107, 171.1-172.558)

USEPA RCRA - Standards Applicable to Generators of Hazardous Waste (40 CFR Part 262)

USEPA RCRA - Standard Applicable to Transporters of Hazardous Waste (40 CFR Part 263)

REQUIREMENT SYNOPSIS

These requirements apply to the marking, storage, disposal, and cleanup of PCBs greater than 50 ppm that occur after their respective effective dates. The PCB Spill Cleanup Policy, Subpart, applies to spills of PCB greater than 50 ppm that occurred after its effective date (i.e., May 4, 1987).

This regulation outlines procedures for the packaging, labeling, manifesting, and transportation of hazardous materials. If residuals from groundwater treatment and/or recovered free product are classified as hazardous, the materials will be packaged, manifested, and transported to a licensed off-site disposal facility in compliance with these regulations.

This requirement sets standards for generators of hazardous waste that address (1) accumulating waste, (2) preparing hazardous waste for shipment, and (3) preparing the uniform hazardous waste manifest. These requirements are integrated with DOT regulations. Any RCRA hazardous wastes being shipped off-site must be shipped in proper containers that are accurately marked and labeled, and the transporter must display proper placards. All waste shipments must be accompanied by an appropriate manifest.

These regulations outline the standards for transportation of hazardous waste off-site. Transporters of hazardous waste must comply with manifest, record keeping, and reporting requirements set forth in these rules. These requirements will be attained through compliance with U.S. DOT Rules for Transportation of Hazardous Waste.

USEPA RCRA ­ Standard Applicable to These regulations outline the standards for transportation of hazardous waste off-site. Transporters of Hazardous Waste (40 CFR Part Transporters of hazardous waste must comply with manifest, record keeping, and reporting 263) requirements set forth in these rules. These requirements will be attained through compliance

with U.S. DOT Rules for Transportation of Hazardous Waste.

USEPA Guidance for Evaluating Technical This guidance clarifies how USEPA will determine whether groundwater restoration is technically Impracticability of Groundwater Restoration impracticable and what alternative measures or actions must be undertaken to ensure that the final (9234.2-25). remedy is protective of human health and the environment. Consistent Implementation of the FY 1993 This memorandum outlines the basic process for evaluating at Tl decision document and is Guidance on Technical Impracticability of intended to promote technically sound, nationally consistent implementation of the Tl guidance. Groundwater Restoration at Superfund Sites (9200.4-14)

Use of Monitored Natural Attenuation at This directive clarifies ERA's policy regarding the use of monitored natural attenuation for the Superfund, RCRA Corrective Action, and UST cleanup of contaminated soil and groundwater in the Superfund program (among others). Sites (9200.4-1 7P)

Overview of ARARs, focus on ARAR Waivers This memorandum provides an overview of ARARs, with a focus on ARAR waivers. (OSWER 9234.2-03/FS)

&ate of Maine Regulatory Requirements

Waste Discharge Licenses (38 M.R.S.A. § Direct or indirect discharges to the waters of the state require a license. 413) Maine Hazardous Waste, Septage, and Solid The rules provide a comprehensive program for handling, storage, and record keeping at Waste Management Act Title 38, Chapter 13 hazardous waste facilities. They supplement the RCRA regulations. and MEDEP Regulations, Chapters 800-802, 8SO 8S1 ftSI-R'm

1

APPENDIX E-3: IDENTIFICATION OF LOCATION-SPECIFIC ARARS

REQUIREMENT REQUIREMENT SYNOPSIS

WETLANDS/FLOODPLAINS Federal Regulatory Requirements

National Environmental Policy Act Applicable The Wetlands Executive Order requires federal agencies to minimize the (NEPA, 42 USC § 4341) and Wetland destruction, loss, or degradation of wetlands, and preserve and enhance natural Executive Order (EO11990), 40 CFR and beneficial values of wetlands. Part 6, Appendix A National Historic Preservation Applicable CERCLA response actions are required to consider possible effects of the Act(NHPA, 16 USC 470 etseq., 40 CFR (if encountered) response activities on any historic property included in or eligible to be included 800) in the National Register of Historic Places.

Clean Water Act Section 404 Applicable Under this requirement, no activity that adversely affects a wetland shall be Requirements for Dredged or Fill permitted if a practicable alternative is available. Material (33 USC 1344; 40 CFR 230)

State of Maine Regulatory Requirements

Maine Natural Resources Protection Act Applicable This act outlines requirements and performance standards for certain activities (NRPA, 38 MRSA § 480) and Permit By in, on, over, or adjacent to freshwater wetlands, streams, ponds, or brooks. The Rule Standards (MEDEP Regulations activities must not unreasonably interfere with certain natural features, such as Ch. 305 natural flow or quality of any waters, nor harm significant aquatic habitat,

freshwater fisheries, or other aquatic life.

Maine Endangered Species Act and Applicable (if The state of Maine has the authority to research, list, and protect any species that Regulations (12 MRS A Section 7751- endangered species are determined to be threatened or endangered, according to state regulations. 7756; 09-137 CMR 008) are identified or The ME Department of Inland Fisheries and Wildlife has developed the

encountered) following categories for the consideration of important species that not threatened or endangered: Maine Watch List, Special Concern List, and Indeterminate Category. The department determines habitat uses on a case-by-case basis. The Maine lists of species may differ from the federal.

OTHER NATURAL RESOURCESFederal Regulatory Requirements Endangered Species Act (ESA, 16 USC Applicable (if This act requires action to avoid jeopardizing the continued existence of listed §§ 1531-1534) encountered) endangered or threatened species or notification of their habitat.

State of Maine Regulatory Requirements

Maine Standards for Classification of Applicable This law establishes the classification of the state's groundwater to protect, Groundwater (38 MRSA, §§ 465-C and conserve, and maintain groundwater resources in the interest of the health, 470) safety, and general welfare of the people of the state. Groundwater is classified

as GW-A, the highest groundwater classification, and is designated as a potential water supply. This classification applicable to remedial objectives.

Maine Endangered Species Act (MESA, Applicable (if The State of Maine has authority to research, list, and protect any species 38 MRSA §§ 7001, 7751-7759) and encountered) deemed endangered or threatened. These species are listed as either endangered Maine Inland Fisheries and Wildlife or threatened in the state regulations. The Maine Department of Inland Fisheries Laws and Regulations (12 MRSA § 7031 and Wildlife has also developed the following administrative categories for et seq.) species not considered endangered or threatened but considered important for

research and further evaluation: Maine Watch List, Special Concern List, and Indeterminate Category. The Department determines appropriate use(s) of various habitats on a case-by-case- basis. The Maine lists may differ from the federal lists of endangered species.

Maine Site Location and Development Applicable This act and regulations govern new development, including new developments Law and Regulations (38 MRSA that handle hazardous wastes and oil. Activities cannot adversely affect existing Sections 481 through 490; MEDEP uses, scenic character, or natural resources in the municipality or neighboring Regs. Ch. 371-377) municipality.

Maine Critical Areas Program and Maine To Be considered These state programs issue policies and regulations governing special habitats or Natural Heritage Program communities.

Maine Critical Areas Act (5 MRSA §§ To Be considered This non-regulatory legislation allows Maine agencies such as the Critical Areas 3310-3316) Program and the Natural Heritage Areas Program to identify, research, and

protect critical areas and endangered or threatened plants.

II Municipal Regulatory Requirements

Mandatory Shoreland Zoning (38 MRSA To Be considered These minimum guidelines and town ordinances apply to activities proposed §§ 435-449) within 250 feet of a high-water mark of a stream or other body of water.

Town Shoreland Zoning Ordinances and State Minimum Guidelines (38 MRSA §§ 1801-1803,1841-1843-A, 1901-1905, 2013) and City of Augusta Comprehensive Plan/Shoreland Zoning Plan

APPENDIX F

F. O'CONNOR SITE SECOND FIVE-YEAR REVIEW

MEDEP CONCURRENCE LETTER

STATE OF M A I N E DEPARTMENT OF ENVIRONMENTAL PROTECTION

JOHN ELIAS BALDACCI DAVID P LITTELL

3CVERMOR COMMISSIONER

September 17, 2007

Mr. Terrence Connelly Office of Site Remediation & Restoration U.S. Environmental Protection Agency 1 Congress Street, Suite 1100 (HBT) Boston, MA 02114-2023

Re: F. O'Connor Superfund Site-Second Five Year Review Augusta, Maine

Dear Mr. Connelly:

The Maine Department of Environmental Protection (MEDEP) has reviewed the draft final Second Five-Year Review Report for the F. O'Connor Site, in August, Maine (received via email on September 9, 2007). The Environmental Protection Agency (EPA) stated that the remedies are protective of human health and the environment as implemented. MEDEP concurs with that statement, as long as the cover and drainage system are maintained, as designed and institutional controls are enforced. The finalization of the Operations and Maintenance Plan will ensure that the site is inspected and maintained on a regular basis. MEDEP also concurs with EPA's recommendations and follow up actions.

Thank you for the opportunity to review and comment on this document and MEDEP looks forward to continuing to working with EPA on environmental issue at this and other sites.

Respectfully // • . ~"-\

(_, Claudia Sait Project Manager Bureau of Remediation & Waste Management

Cf: File Ted Wolfe-MEDEP Hank Aho

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