Superfund Record of Decision: New Bedford, MA

United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R01-9
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50272-101
1 REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R01-90/045
2.
4. Tide and Subtitle
^^UPERFUND RECORD OF DECISION
^Bew Bedford, MA
| First Remedial Action
7. Author(a)
9. Performing Organization Name and Addiesa
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
3. Recipient's Accession No.
5. Report Date
04/06/90
6.
8. Performing Organization Rept No.
10. Project/Task/Work Unit No.
11. Contnct(C) or Grsnt(G) No.
(C)
(G)
13. Type o( Report t Period Covered
800/000
14.
15. Supplementary Notes
18. Abstract (Limit 200 words)
The New Bedford site is a harbor area in the port city of New Bedford, Massachusetts,
approximately 55 miles south of Boston. Two electrical capacitor manufacturing
facilities, the Aerovox facility and the Cornell-Dubilier Electronics facility, are
located along the New Bedford Harbor and were major PCB users from the 1940s to 1978,
,en EPA banned the use of PCBs. These manufacturers released PCB-contaminated
tewater onto shoreline mudflats and into the harbor. As a result of the widespread
B contamination, the State closed three fishing areas in the harbor in 1979,
resulting in the loss of approximately 18,000 acres of productive lobstering ground.
Between 1982 and 1985, EPA and the Coast Guard posted warnings notifying the public of
fishing and swimming restrictions. The site has been divided into three study areas
which include the Hot Spot area, the Acushnet River Estuary, and the Lower Harbor and
Upper Buzzards Bay. This Record of Decision (ROD), the first of two operable units, is
an interim remedy and addresses the 5-acre Hot Spot area, located along the western
bank of the Acushnet River Estuary adjacent to the Aerovox facility. This first
interim action operable unit will remove approximately 48 percent of the total PCB mass
in the sediment from the estuary portion of the site, which is a continuing source of
contamination throughout the entire site. A subsequent ROD will address the
remediation of the Acushnet River Estuary and the Lower Harbor and Upper Buzzards Bay.
(See Attached Sheet)
MA
17. Document Analyaie a. Oeacrlptora
Record of Decision - New Bedford,
First Remedial Action
Contaminated Medium: sediment
Key Contaminants: organics (PCBs), metals (lead)

b. IdentiHers/Open-Ended Terms
COSATI Field/Group
liability Statement
19. Security Claas (This Report)
None
20. Security Claas (This Page)
None
21. No. of Pages
264
22. Price
(Set. ANSI-Z39.18)
See Instruction* an Rtvtn*
OPTIONAL FORM 272 (4-77)
(Formerly NT1S-35)
Department bl Commerce
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EPA/ROD/R01-90/045
New Bedford, MA
First Remedial Action

^^stract (continued)

The primary contaminants of concern affecting the sediment in the New Bedford Harbor
are .organics including PCBs and metals including lead.

The selected interim remedial action for the site includes dredging 10,000 cubic
yards of contaminated sediment, dewatering the sediment using an existing confined
disposal facility (CDF) and incinerating the sediment onsite; solidifying/stabilizing
the residual ash to immobilize metals, if a leaching test indicates it is necessary;
treating effluent from the dewatering process using the best available control
technology prior to discharge into the harbor; and passing exhaust gases from the
incineration process through air pollution control devices prior to their release into
the atmosphere. During the remedial action the solidified/stabilized ash will be
temporarily stored onsite, and following the completion of the remedial action, the
ash will be stored and covered in a secondary cell of the CDF. Ultimate disposition
of the ash will be addressed in the second operable unit. The estimated total cost of
this remedial action is $14,379,300. No O&M costs were specified.
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RECORD OF DECISION SUMMARY
NEW BEDFORD HARBOR/
HOT SPOT OPERABLE UNIT
NEW BEDFORD, MASSACHUSETTS
APRIL 1990
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION I
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RECORD OP DECISION
REMEDIAL ALTERNATIVE SELECTION
Site Name and Location

New Bedford Harbor/Hot Spot Area
New Bedford, Massachusetts
Statement of Purpose

This Decision Document presents the selected remedial action for
this Site developed in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980,
as amended (CERCLA), and to the extent practicable, the National
Contingency Plan (NCP), 40 CFR Part 300 et seq., 50 Federal
Register 47912 (November 20, 1985).

The Commonwealth of Massachusetts concurs with the selected
remedy. A copy of the concurrence letter is included as
Appendix C.

Statement of Basis

This decision is based on the Administrative Record which was
developed in accordance with Section 113 (k) of CERCLA .and which
is available for public review at the information repositories
located at the New Bedford Free Library, in New Bedford,
Massachusetts, and at the EPA offices at 90 Canal Street in
Boston, Massachusetts. Appendix B to this document identifies
the items contained in the Administrative Record upon which the
selection of this remedial action is based.
Assessment of the Sit«

Actual or threatened releases of hazardous substances from this
portion of the Site, if not addressed by implementing the
response action selected in this Record of Decision, may present
an imminent and substantial endangerment to public health,
welfare or the environment.

Description of the Selected Remedy

The selected remedial action for the New Bedford Site/Hot Spot
Area is the Hot Spot Operable Unit, the first of two operable
units planned for the New Bedford Harbor Superfund Site. The Hot
Spot Operable Unit consists of source control measures, which.
will also control the continuing migration of contaminants from
the Hot Spot to other portions of the Site. The major components
of the Hot Spot remedial measures include:
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Dredging. Approximately 10,000 cubic yards of contaminated
sediments will be-'Sremoved using a cutterhead dredge.
Dredging will occur in the Hot Spot Area at depths of up to
four feet to remove sediments with PCB concentrations of
4,000 ppm or greater. Various control options will be used
to minimize and control sediment resuspension.

Transportation and Dewatering. The dredged sediments will
be transported to the Pilot Study cove area by a floating
hydraulic pipeline, where the sediments will be dewatered.
Effluent produced during the dewatering process will be
treated to reduce PCBs and heavy metals using best
available control technology prior to discharge back into
the Harbor.

Incineration. The dewatered sediments will be incinerated
in a transportable incinerator that will be sited at the
Pilot Study cove area. The extremely high temperatures
achieved by the incinerator will result in 99.9999%
destruction of PCBs. Exhaust gases will be passed through
air pollution control devices before being released into
the atmosphere to ensure that appropriate health and safety
and air quality requirements are met.

Stabilization. Following incineration, the Toxicity
Characteristic Leaching Procedure (TCLP), a leaching test,
will be performed on the ash to determine if it exhibits
the characteristic of toxicity and is, therefore,
considered a hazardous waste under the Resource
Conservation and Recovery Act (RCRA). If the TCLP test
reveals that the ash is a RCRA hazardous waste, the ash
will be solidified such that metals no longer leach from
the ash at concentrations that exceed the standards set
forth for determining the toxicity of a material.

During remedial activities, (solidified) ash will be temporarily
stored in an area adjacent to the existing Confined Disposal
Facility (CDF), a containment structure built on the New Bedford
Harbor shoreline during previous Site studies. Following
completion of the remedial activities, the (solidified) ash will
be stored in the secondary cell of the CDF. Storage of the
treated material will comply with the solid waste requirements.
Ultimate disposition of this material will be addressed in the
second operable unit for the Site.

Sediment removal and incineration will provide significant
progress toward long-term protection of public health and the
environment. Incineration is a proven technology that
permanently destroys PCBs and is readily implementable for this
volume of material. The selected remedy will, permanently reduce
the mobility, toxicity and volume of PCBs in the Hot Spot and
will also reduce the amount of PCBs and heavy metals affecting
the remainder of the Harbor. Short-term protection will be
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achieved by engineering controls to limit the emission of
contaminants during excavation and treatment.

This interim action will comply with levels or standards of
control equivalent to legally applicable or relevant and
appropriate standards, requirements, criteria, or limitations
(ARARs) specific to this action, including but not limited to,
operation of the incinerator. However, this interim action will
not" attain certain levels or standards of control that might be
ARARs. This interim remedial action is only part of a total
remedial action that will attain ARARs when completed.

Declaration

This interim action is protective of human health and the
environment, complies with Federal and State applicable or
relevant and appropriate requirements directly associated with
this action, and is cost-effective. This action utilizes
permanent solutions and alternative treatment technologies to the
maximum extent practicable, and this action satisfies the
statutory preference for treatment as a principal element of the
remedy. This action does not, however, constitute the final
remedy for the entire New Bedford Harbor Site. Subsequent
actions are planned to address fully the remaining threats posed
by this Site.
Xaudie Belaga (j
fj(egional Administrator
^ Region I
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NEW BEDFORD HARBOR/
HOT SPOT OPERABLE UNIT

TABLE OF CONTENTS

I. SITE NAME, LOCATION AND DESCRIPTION 1

II. SITE HISTORY AND ENFORCEMENT ACTIVITIES 2
A. Response History 2
B. Enforcement History 4

III. COMMUNITY RELATIONS 6

IV. SCOPE AND ROLE OF OPERABLE UNIT 7

V. SUMMARY OF SITE CHARACTERISTICS 8
A. Sediment 8
B. Surface Water 12
C. Biota 13

VI. SUMMARY OF SITE RISKS 14
A. General Feasibility Study and Risk Assessment
Information 14
B. Contaminants of Concern 15
C. Public Health Risks/Human Health Evaluation ... 16
D. Ecological Risk 17
s
VII. DOCUMENTATION OF NO SIGNIFICANT CHANGES 17

VIII. DEVELOPMENT AND SCREENING OF ALTERNATIVES 18
A. Statutory Requirements/Response Objectives ... 18
B. Technology and Alternative Development and
Screening 19

IX. DESCRIPTION/SUMMARY OF THE DETAILED ANALYSIS OF
ALTERNATIVES 21
A. Capping Alternative for the Hot Spot 21
B. Summary of the Detailed Analysis of
Alternatives 23

X. THE SELECTED REMEDY 26
A. Description of the Selected Remedy 26
B. Comparative Analysis and Rationale for
Selection 28

XI. STATUTORY DETERMINATIONS 32
A. The Selected Remedy is Protective of Human
-Heaith—and the Environment 33
B. The Selected Remedy Attains ARARs to the Extent
Required by Section 121 of CERCLA . 33
C. The Selected Remedial Action is Cost-Effective . 36
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D. The Selected Remedy Utilizes Permanent
Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies
to the Maximum Extent Practicable 36
E. The Selected Remedy Satisfies the Preference
for Treatment as a Principal Element 37

XII. STATE ROLE 37
ii
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LIST OF FIGURES

Figure ~ * Page

1. Site Location Map 38
2. Geographical Study Areas 39
3. Fishing Closure Areas 40
4. Hot Spot Sediment PCB Concentrations, 0-12 inches . 41
5. Estuary PCB Concentrations, 0-12 inches 42
6. Estuary PCB Concentrations, 12-24 inches 43
7. Estuary PCB Concentrations, 24 - 36 inches 44
8. PCB Mass Versus Remediation Volume 45
9. Surface Water PCB Concentrations ... 46
10. Lobster PCB Concentrations , . . . . 47
11. Direct Contact Areas with Sediment 48
12. Preferred Alternative 49
LIST OF TABLES
Table Page

1. Edible Tissue PCB Concentrations 50
2. Public Health Risk Assessment; Direct Contact .... 51
3. Public Health Risk Assessment; Ingestion of Biota* . . 52
4. Summary of Hot Spot Remedial Alternatives 53
5. Comparative Analysis Summary of Alternatives .... 54
6. Action-Specific ARARs 57
APPENDICES

Appendix A - Responsiveness Summary
Appendix B - Administrative Record Index
Appendix C - State Concurrence Letter
111
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ROD DECISION SUMMARY
NEW BEDFORD HARBOR HOT SPOT OPERABLE UNIT

I. SITE NAME, LOCATION AND DESCRIPTION

New Bedford, Massachusetts, is a port city located at the head of
Buzzards Bay, approximately 55 miles south of Boston (Figure 1).
New Bedford is nationally known for its role in the development
of the whaling industry in the early 1800's. Today, the harbor
is home port to one of the largest commercial fishing fleets in
the United States.

In the course of developing Feasibility Studies (FS) for the
Site, EPA divided the Site into three geographical study areas:
the Hot Spot Area, the Acushnet River Estuary, and the Lower
Harbor and Upper Buzzards Bay (Figure 2). The Hot Spot is an
area of approximately five acres located along the western bank
of the Acushnet River Estuary, directly adjacent to an electrical
capacitor manufacturing facility, the Aerovox facility. EPA has
defined the Hot Spot as those areas where the sediment PCB
concentration, is 4,000 parts per million (ppm) or greater. PCB
concentrations in this area range from 4,000 ppm to over 200,000
ppm. Contamination at levels of 4,000 ppm and greater are found
at depths up to four feet, but for the most part, within the top
two feet. In addition to PCBs, heavy metals (notably cadmium,
chromium, copper, and lead) are found in the sediment. The
remedial volume for this area is approximately 10,000 cubic yards
of sediment, and it contains approximately 48 percent of the
total PCB mass in sediment from the Estuary portion of the Site,
and approximately 45 percent of the total PCB mass in sediment
from the entire Site. Refer to Sections IV and V for further
discussion of the Hot Spot, including the scope and role of the
Hot Spot operable unit and site characteristics. The remainder
of the Site to be addressed in a subsequent operable unit is
described below.

The Acushnet River Estuary is an area of approximately 230 acres
(excluding the Hot Spot), extending from the Wood Street Bridge
to the north, to the Coggeshall Street Bridge to the south.
Sediment PCB concentrations in this area (excluding the Hot Spot
area) range from below detection to approximately 4,000 ppm.
Sediment metals concentrations range from below detection to over
7,000 ppm.

The Lower Harbor area consists of approximately 750 acres,
extending from the Hurricane Barrier, north to the Coggeshall
Street Bridge. Sediment PCB concentrations range from below
detection to over 100 ppm. Sediment metals concentrations range
from below detection to approximately 3,000 ppm.
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The Upper Buzzards Bay portion of the Site area extends from the
Hurricane Barrier to the southern boundary of Fishing Closure
Area III, and includes an area of approximately 17,000 acres.
Sediment PCB concentrations here range from below detection up to
100 ppm in localized areas along the New Bedford shoreline near
combined sewer and stormwater outfalls.

A more complete description of the Site can be found in Section 2
of the Feasibility Study.

II. SITE HISTORY AMD ENFORCEMENT ACTZVZTZE8
A. Response History

In 1976, the U.S. Environmental Protection Agency (EPA) conducted
a New England-wide survey for polychlorinated biphenyls (PCBs).
During this survey, high levels of PCB contamination were
discovered in the marine sediment over a widespread area of New
Bedford Harbor. In addition to PCBs, heavy metals (notably
cadmium, chromium, copper, and lead) were found in the sediment.
The survey and subsequent field studies also revealed that PCB
contamination was not limited to sediment. Marine biota were
also affected. Concentrations of PCBs in fish and shellfish were
found to be in excess of the U.S. Food and Drug Administration
(FDA) tolerance limit of 5 parts per million (ppm) for edible
tissue. (FDA has subsequently reduced the PCB tolerance level to
2 ppm in 1979.) In 1977, the Massachusetts Department'of Public
Health (DPH) issued a public warning against consumption of
shellfish or bottom fish from within the harbor and eastern
sections of Buzzard's Bay to protect public health.

As a result of the widespread PCB contamination and the
accumulation of PCBs in marine biota, the Massachusetts
Department of Public Health established three fishing closure
areas in New Bedford Harbor in September 1979 (Figure 3). These
closures remain in effect. Area I is closed to all fishing,
including finfish, shellfish, and lobsters. Area II is closed to
the taking of lobsters and bottom-feeding finfish, such as eels,
flounders, scup, and tautog. Area III is closed to lobstering
only. Closure of the New Bedford Harbor and upper Buzzards Bay
area to lobstering has resulted in the loss of approximately
18,000 acres of productive lobstering ground.

Two electrical capacitor manufacturing facilities, the Aerovox
facility and the Cornell-Dubilier Electronics facility located on
the Harbor, were major users of PCBs from the time their
operations commenced in the 1940s until 1978, when EPA banned the
use of PCBs. These manufacturers released PCBs onto the ,
adjoining shoreline mudflats of the plants and into New Bedford
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Harbor, through discharged wastewaters containing PCBs and
through alleged intentional dumping.

The New Bedford Harbor Site was added to the EPA Superfund
National Priorities List (NPL) in July 1982. Also in 1982, the
Coast Guard placed warning signs along the shoreline of the Site.
These signs, written in both English and Portuguese, served to
notify the public of the restrictions against fishing and
swimming. Additional warning signs were installed by EPA and the
City of New Bedford in 1984 and 1985.

Remedial studies

Numerous investigations have been conducted over the last decade
to physically characterize the New Bedford Harbor Site, to
determine the extent of PCB and metals contamination, and to
assess the fate and transport of these contaminants. The major
studies are summarized below. Other investigations, which were
used as reference material for these studies, have been made
publicly available in the Administrative Record.

Remedial Action Master Plan (1983)

The results of studies completed through early 1983 were
compiled into a Remedial Action Master Plan (RAMP) for the
Site in May 1983. This assessment included an area-wide
air monitoring program; a sediment PCB profile for the
Estuary and the Harbor; biota sampling for the Estuary/
Harbor and Bay; and a study of the contamination within the
New Bedford sewer system. The plan included recommenda-
tions for studies to further define the nature and extent
of contamination.

Acushnet River Estuary FS (1984)

The results and recommendations of the RAMP led to a "fast-
track" Feasibility Study (FS) for the 200-acre estuary area
north of the Coggeshall Street Bridge. Four of the five
remedial options presented in this FS involved dredging of
the contaminated sediments. During the public comment
period, concerns were raised surrounding the ability to
dredge the contaminated sediments without causing
additional impacts, both short- and long-term. As a
result, the remedy selection process was extended until
studies could be completed to address these concerns.

Engineering Feasibility Study (1989V

To answer questions regarding the potential impacts 'of
dredging the contaminated sediment, the Corps of Engineers
was asked to complete a dredging and disposal study. This
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Engineering Feasibility Study (EFS) was conducted by the
Corps' Waterways Experiment Station. The EFS consisted of
bench and field scale experiments to address sediment and
contaminant releases during dredging, efficacy of shoreline
and aquatic disposal locations, leachate production from
disposal facilities, and physical/chemical sediment
profiles.

Pilot Dredging and Disposal Study (1989)

The Pilot Dredging and Disposal study, an outgrowth of the
EFS, was a field test of three dredges and two disposal
techniques for 9,000 cubic yards of sediment from the
Estuary. The focus of this study was an attempt to verify
whether the dredging and disposal techniques could be
implemented without causing releases that could adversely
impact public health or the environment. Additionally, the
study was used to determine the optimal operating
parameters for the dredging equipment and to develop
monitoring programs to detect and evaluate contaminant
releases.

Hot Soot Feasibility Study f19891

The Hot Spot Feasibility Study was completed for the Hot
Spot Area of the Site. The response objectives and a
summary of the alternatives evaluated are provided in
Sections VIII and IX of this document.

Overall Feasibility Study fonooincM

This feasibility study was designed to combine the previous
studies described above and to address the Estuary and
Lower Harbor/Bay areas of the New Bedford Site. This study
is scheduled to be released in June 1990.
B. Enforcement History

A number of enforcement actions have been taken related to PCB
contamination of New Bedford Harbor and adjacent properties.
These actions are briefly summarized below.

Cornel1-Dubilier Electronics, Inc. (Cornell-Dubilier) and EPA
signed a consent agreement and final order under the Toxic
Substances Control Act (TSCA) in May 1982 (TSCA Docket No. 81-
1001). This agreement addressed PCB handling procedures,
discharges and releases to the municipal sewer system and
surrounding areas, and groundwater monitoring requirements.
Subsequently, EPA issued an administrative order to Cornell-
Dubilier under section 106 of CERCLA in September 1983 (Docket
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No, 83-1047) regarding releases of PCBs into the municipal sewer
system.

Aerovox Incorporated (Aerovox) signed a consent order under
section 106 of CERCLA in May 1982 (Docket No. 81-964), regarding
contamination on their property adjacent to the Harbor. This
order called for a cut-off wall and cap system to isolate
contaminated soil, groundwater monitoring, and maintenance
requirements.

EPA issued an administrative order to the City of New Bedford
under section 309 of the Clean Water Act in December 1982 (Docket
No. 83-06), regarding violations of the City's National Pollutant
Discharge Elimination System (NPDES) permitted discharge from the
municipal wastewater treatment plant (WWTP) into the Harbor. EPA
issued another administrative order to the City under section 106
of CERCLA in September 1983 (Docket No. 83-1048), regarding
releases of PCBs into the municipal sewer system.

On December 9, 1983, the United States filed a complaint on
behalf of the National Oceanic and Atmospheric Administration
(NOAA) under section 107 of CERCLA, seeking damages for injury to
natural resources in New Bedford Harbor from releases of PCBs.
The next day, the Commonwealth of Massachusetts filed its own
section 107 action. The cases have been consolidated. On
February 28, 1984, the complaint was amended to include claims on
behalf of EPA for recovery of response costs incurred or to be
incurred, under section 107 of CERCLA and for injunctiye relief
under Section 106 of CERCLA and other environmental statutes.

The United States brought the action against six companies which,
at various times, owned and/or operated one of the two electrical
capacitor manufacturing plants adjacent to New Bedford Harbor.
The two plants are located approximately two miles apart. One of
the plants, the Aerovox plant, is at the northernmost end of the
inner Harbor on the Acushnet River Estuary* where the Acushnet
River flows into the Harbor. The other plant, the Cornell-
Dubilier plant, is a short distance south (i.e., seaward of) a
hurricane barrier, which separates the inner Harbor from the
outer Harbor.

Those entities which are potentially liable for the damages to
the Harbor and for EPA's response costs (the PRPs) have been
involved throughout the RI/FS and remedy selection process. The
PRPs submitted extensive comments during the public comment
period. A summary of the PRPs1 comments and EPA's responses to
those comments are included in the Responsiveness Summary as
Appendix A to this document. All of the PRPs1 comments, the
summary of the comments, and EPA's responses to the comments are
included in the Administrative-Record.
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Additionally, the EPA held an informal public hearing in New
Bedford on August 22, 1989 at the specific request of AVX
Corporation (AVX), one of the PRPs. In response to EPA's
Proposed Plan for remediation of the Hot Spot, AVX developed its
own proposal for addressing contaminated sediments in the Hot
Spot and Estuary. AVX requested an opportunity to present its
proposal to the EPA and the State. EPA granted AVX such an
opportunity at the August 22, 1989 meeting. The transcript of
this hearing is included in Attachment B to the Responsiveness
Summary.

ZZZ. COMMUNITY RELATIONS

Throughout the Site's history, community concern and involvement
have been and continue to be high. Consistent with its statutory
obligations, EPA has kept the local community and other
interested parties apprised of the Site activities through its
participation at numerous meetings and its dissemination of
various press releases and fact sheets. In order to better
communicate with the local Portuguese community, EPA produced
Portuguese translations of all public information fact sheets and
provided a translator at all public hearings and meetings.

Concerns in the bordering communities initially focused on
potential public health impacts as a result of living near the
Harbor or eating fish caught in the Harbor, potential impacts on
the local fishing industry, and potential limitations on
waterfront development activities. Community concerns now also
include the environmental, economic and health impacts of
remedial alternatives evaluated for the Hot Spot portion of the
Site, and ensuring that, following Hot Spot remediation,
remaining Harbor contamination will be addressed.

EPA has presented the plans for and the subsequent results of
site investigations and feasibility studies at a series of public
meetings sponsored by EPA and at regular meetings of the Greater
New Bedford Community Work Group (CWG). EPA also awarded a
$50,000 Technical Assistance Grant in November 1988 to the CWG to
hire a consultant to review the studies conducted by EPA.

In June 1989, EPA made the Administrative Record available for
public review at EPA's offices in Boston and at the New Bedford
Public Library. EPA published a notice and a brief analysis of
the Proposed Plan in two local, newspapers of general circulation,
The Standard Times and The Portuguese Times, on July 27, 1989.
EPA also made the Proposed Plan available to the public at the
New Bedford and Fairhaven public libraries. The Administrative
Record was subsequently updated on August 3, 1989 and on
September 8, 1989, to include additional documents considered by
the EPA for the Hot Spot Operable Unit decision.
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EPA held an informational meeting on August 3, 1989 to present
the results of the Hot Spot-feasibility Study, to discuss the
Proposed Plan, and to answer any questions that interested
persons had. This meeting also marked the beginning of the
public comment period during which the public, including the
PRPs, was invited to comment on the alternatives-presented in the
Feasibility Study, the Proposed Plan, and on any other documents
previously released to the public or included in the
Administrative Record.

The EPA held an informal public hearing on August 16, 1989 to
accept oral comments. On the following day, August 17, 1989, EPA
issued a press release announcing the extension of the public
comment period from September 1, 1989 to October 2, 1989.

A second public meeting was held on August 22, 1989, to allow the
PRPs an opportunity to present an alternative to EPA's Proposed
Plan. Following this meeting, the public comment period was
extended for a final time until October 16, 1989. The public
comment period lasted a total of 74 days, considerably longer
than average.

Finally, on September 25, 1989, the CWG sponsored a meeting to
provide an opportunity for its members and members of the public
to ask EPA representatives about EPA's Proposed Plan or AVX
representatives about their proposed alternative.

A transcript of these public meetings and the comments -submitted
to the EPA, along with the EPA's response to these comments, are
included in the Responsiveness Summary as Appendix A to this
document.

A more detailed chronology of EPA's community relations
activities for the Site can be found in Section II of the
attached Responsiveness Summary.
IV. SCOPE AND ROLE OF OPERABLE UNIT

This Hot Spot Operable Unit is the first of two operable units
planned for the New Bedford Harbor Site. Operable units are
discrete actions that comprise incremental steps toward a final
remedy. They may be actions that completely address a
geographical portion of a site or a specific site problem. The
Hot Spot Operable Unit addresses both a geographical portion of
the Site and a specific Site problem.

The Hot Spot Area is an area of approximately 5 acres along the
western bank of the Acushnet River Estuary adjacent to the
Aerovox facility. It is noteworthy because of the extremely high
levels of PCBs that have been detected in the sediment. Levels
of PCBs in the Hot Spot sediments range from 4,000 ppm to over
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200,000 ppm. Dermal contact and incidental ingestion of this
sediment and ingestion of contaminated fish and shellfish could
pose a significant risk to public health. In addition, PCB
contamination threatens marine organisms. Potential routes of
exposure for marine organisms include direct contact with the
sediment, contact with contaminants in the water column, and
ingestion of contaminated food. Finally, the Hot Spot continues
to act as a source of contamination throughout the entire Site.
The Hot Spot Operable Unit is designed to respond to these
significant threats.

This interim action is protective of human health and the
environment by providing for the removal and treatment of the
highly contaminated sediments in the Hot Spot. Subsequent
actions are currently being developed and evaluated to address
fully the principal threats posed by the remainder of the Site.
This interim action is consistent with any planned future actions
because this action calls for the removal of approximately 48
percent of the total PCB mass in sediment from the estuary
portion of the Site, which acts as a continuing source of
contamination throughout the entire Site.

V. SUMMARY OF SITE CHARACTERISTICS

Numerous studies and reports completed for the New Bedford Harbor
Superfund Site have outlined the nature and extent of
contamination, the location and functional value of the wetland
areas, the fate and transport of PCBs in the estuarine
environment, and the risks associated with sediment
contamination. These reports, which are included in the
Administrative Record, highlight the relationship of the PCB
contamination in the Hot Spot Area to PCB contamination in the
Estuary and the Lower Harbor and Bay. Chapter 2 of the
Feasibility Study contains an overview of these studies. The
significant findings of the -studies are summarized below.

A. Sediment

The following five sediment sampling data sets describe the
nature and extent of PCB contamination in sediment in the
Acushnet River Estuary, including the Hot Spot Area. These data
sets were used to determine the horizontal and vertical extent of
PCB contamination in the Estuary, and PCB concentration maps were
prepared using these data. A summary of these data sets is
presented in Appendix A of the Hot Spot Feasibility Study.

U.S. Coast Guard Sediment Sampling Program (1982)
U.S. Army Corps of Engineers (USACE) Field
Investigation Team (FIT) Sampling Program (1986)
Battelle Hot Spot Sediment Sampling Program (1987)

8
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USAGE Wetlands and Benthic Sediment Sampling Program
(1988)
USAGE Hot Spot Sediment Sampling Program (1988)

The above five data sets were also used for the contamination
assessment and for the development of the PCB concentration maps.
Other data sets included in the Administrative Record, but not
specifically used in the development of the PCB concentration
maps, include:

DEQE sampling (1981)
EPA sampling (November 1981)
Aerovox sampling (March 1982)
Aerovox/General Electric sampling (June 1986)
AVX sampling (reported October 1989)

These data are consistent with the magnitude and location of PCB
contamination identified in the previously mentioned data sets.
These later data sets contain the highest results for any
sampling taken in the Hot Spot: 190,000 ppm (EPA, 1981); 130,000
ppm (AVX, 1989); and 247,000 ppm (Aerovox, 1982). These samples
were taken in the mudflats near the outfalls of the Aerovox
facility.

The results of these data are described in further detail in the
following subsections.
The distribution of PCBs within the sediments of the Hot Spot
Area at the depth of 0 to 12 inches is presented in Figure 4.
The vertical and horizontal extent of PCB contamination in the
Estuary, including the Hot Spot, is illustrated in the
concentration maps prepared for the following three depths: zero
to 12 inches (Figure 5), 12 to 24 inches (Figure 6), and 24 to 36
inches (Figure 7).

The sediment data also illustrate the relationship between the
quantity of PCBs within the Hot Spot Area as compared to the
entire Estuary (Figure 8). Approximately 48% of all the PCBs
within the Estuary are located in the Hot Spot. EPA has defined
the Hot Spot as those areas where the sediment PCB concentration
is 4,000 ppm or greater.

Other Contaminants

In addition to PCBs, other contaminants are present throughout
the New Bedford Harbor Site. These contaminants include
polycyclic~a"romat±c~hydrocarbons (PAHs) and heavy metals (copper,
chromium, lead, and cadmium). The extent of PAH and heavy metal
contamination is presented in the Hot Spot Feasibility Study and
-------
the Additional Contaminants of Concern Report, which are included
in the Administrative Record.

Within the Estuary portion of the Site, PAH compounds were found
to be co-located with PCBs. However, the range of PAH
concentrations in the sediment was significantly less than the
range of PCB concentrations. Total PAH sediment concentrations
range from below detection limit to 930 ppm, with an average
concentration of approximately 70 ppm. The highest PAH
concentration of 930 ppm was detected in the Hot Spot Area.
Because no discrete areas of elevated levels of PAH compounds
were observed, it is probable that PAH contamination is caused by
non-point sources such as urban runoff. PAH concentrations
detected in the sediment are similar to PAH concentrations
detected in other urban and industrialized areas. PAH compounds
can be effectively treated by the technologies identified to
treat PCB contamination. Thus, the selected method to treat the
PCB contamination in the Harbor will effectively treat the PAH
contamination.

Similar to PCB contamination, the metals concentrations are
greatest in the top foot of sediment and decrease with depth.
Metal concentrations have been detected in the PCB Hot Spot Area
and extend throughout the 36-inch remediation depth. Many
treatment technologies capable of treating the PCBs are
ineffective for treating metals. For this reason, an additional
treatment step may be required to treat the metals remaining in
the sediment after treatment for PCBs (e.g., solidification).
However, the area of highest metal contamination in the Estuary
is not co-located with the PCB Hot Spot Area. The location of
the high metal-contaminated sediment correlates with the location
of industrial discharge and/or combined sewer overflow discharge
pipes. Contamination outside of the Hot Spot Area will be
addressed in the second operable unit for the Site.

Hot Spot PCB Migration

The results of several monitoring programs demonstrate that
approximately 2 pounds of PCBs migrate out of the upper Estuary
daily. These PCBs are ultimately transported to portions of the
Lower Harbor and Buzzards Bay, where they are redeposited,
volatilized into the atmosphere, or taken up into the food chain
by aquatic biota. The PCBs which leave the Estuary, or the PCB
flux, are composed of a dissolved (soluble) fraction and a
particulate (sediment) fraction. Assessments of sediment and
contaminant migration were based on field, laboratory, and model
studies.

Transport of dissolved PCBs throughout the Harbor contributes to
PCB migration to a greater extent than erosion and transport of
sediment bed material. The following brief discussion focuses on
the movement of dissolved PCBs from the bed sediment to the water

10
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column,- because studies show that the majority of the
contaminated suspended solids become contaminated through contact
with the water column and not from resuspension activities. A
more complete discussion of Hot Spot PCB migration can be found
in the following documents in the Administrative Record: Hot Spot
FS (see pages 2-17 through 2-22); Corps of Engineers' Engineering
Feasibility Study (see Report 2); and several reference articles
(see Brown and Wagner, 1986 and Brownawell, 1986).

Within the sediment, many processes are actively moving the PCBs
into the overlying water. The following mechanisms contribute to
the mobilization of the PCBs:

-desorption, or release of PCBs from the bed sediment
and diffusion into the overlying water;

molecular diffusion of PCBs within the pore water of
the sediment; and

bioturbation, or mixing of the sediment by organisms.

The desorption process is influenced by the sediment organic
carbon content, the specific physical and chemical properties of
the PCBs, and the absorbed contaminant concentration. This
desorption process is apparent by observing the extremely high
water column concentrations of PCBs in the vicinity of the Hot
Spot. Once into the water column, the PCBs are transported to
other areas of the Site. Additionally, PCBs are volatilized into
the atmosphere from the surface water and exposed mudflat areas
continuously.

During the public comment period for the Hot Spot operable unit,
the Potentially Responsible Parties (PRPs) submitted reports that
estimate the PCB flux out of the surficial sediments within the
Estuary. The results of the PRPs1 studies indicate that at least
30% of the entire flux from the Estuary sediments is derived from
the areas of contamination in excess of 4,000 ppm PCBs (i.e., the
Hot Spot). This information supports the importance of the Hot
Spot Area in the migration of PCBs within and away from the Site.
Refer to the PRP document "Tidal Cycle Flux Measurement Data" and
Section 4 of the Responsiveness Summary for further discussion.

Contaminant Fate in the Environment

The EPA recognizes that biotransformation of PCBs in New Bedford
Harbor sediment appears to be occurring. However, studies
conducted to date do not provide sufficient data for a reliable
estimation of in-situ biochemical decay rates or half-lives, as
well as the toxicity of the decay products. This information is
crucial to evaluate the length of time that would be required for
removal of PCBs from the Hot Spot sediment by natural processes.
Research suggests that the half-life of anaerobic degradation of

11
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heavily chlorinated PCBs may range from 7 to 50 years (Brown and
Wagner, 1986). Based on this half-life estimate and assuming
first order decay, the time required for biodegradation to reduce
a sediment PCB concentration of 4,000 ppm (the lower limit of the
Hot Spot) to 50 ppm would be approximately 50 to 300 years. The
EPA finds this time frame for remediation unacceptable,
especially when there are other remedial alternatives currently
available for implementation.

Therefore, given the quantity and high level of PCB contamination
in the Hot Spot sediment, the EPA believes the Hot Spot will
remain a source of contamination, and that contaminants will
continue to migrate to the entire Site if not addressed.
Although the EPA recognizes that PCBs undergo transformation
processes to varying degrees in the environment, no scientific
data has been provided to the EPA to date, nor is EPA aware of
any such data, which documents that the levels of contamination
in the Hot Spot would be reduced to levels that the EPA believes
would no longer present a risk to human health or the environment
within a reasonable timeframe.
B. Surface Water

The mean PCB water column concentrations at the New Bedford
Harbor Site range from approximately 3,900 parts per trillion
(ppt) in the vicinity of the Hot Spot to 4 ppt in portions of
Buzzards Bay. Sampling locations and corresponding mean PCB
concentration values are depicted in Figure 9. These values were
generated using data obtained by Battelle Ocean Sciences in 1987.
In the Hot Spot Area, PCB concentrations grossly exceed the
Ambient Water Quality Criteria (AWQC) for PCBs (chronic effects
on aquatic life) of 30 ppt. PCB concentrations also exceed the
AWQC throughout the remainder of the Estuary and the Lower
Harbor.

The water column data also reflect the movement of PCBs from the
sediment into the water column. The correlation between water
column concentrations and the underlying sediment concentrations
is as follows: the higher the sediment concentration, the higher
the water column concentration. This correlation demonstrates
the movement of the PCBs into the water column. The water column
data, combined with EPA PCB flux measurements at the Coggeshall
Street bridge, indicate that surface water from within the
Estuary is transporting PCBs to other areas of the Site. The
extremely high PCB concentrations, the elevated surface water
concentrations, the quantity of PCBs within the area, as well as
the analytical modeling conducted by the PRPs described in
Section V.A above, provide evidence that the Hot Spot is a
significant source to the remainder of the Site, in particular,
to the Estuary portion.
12
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C. Biota

Sampling data show that aquatic biota are contaminated with PCBs.
It is also known that aquatic biota, bioaccumulate and
bioconcentrate PCBs. Contamination occurs when biota come into
contact with contaminated sediment or surface water, or via the
ingestion of contaminated organisms. Public health is threatened
because contaminated biota from the Harbor may be caught and
consumed.

In certain biota samples, the edible portion was found to contain
levels of PCBs in excess of the 5 ppm tolerance limit established
by the Food and Drug Administration (FDA). This limit was
subsequently lowered to 2 ppm by the FDA in 1979.

The Massachusetts Department of Public Health (DPH) determined
that under the FDA standard, the biota were "adulterated" within
the meaning of state law, and responded to the public health
threat by establishing Fishing Closure Areas within the Harbor
and portions of Buzzards Bay.

Benthic invertebrates and fish are unable to thrive in the Hot
Spot Area. However, because the Hot Spot is a significant point
of origin for the migration of PCBs throughout the Harbor, biota
in the rest of the Harbor are affected by Hot Spot contamination.
Refer to Sections V.A, V.B, and Section 4 of the Responsiveness
Summary portion of this document for discussion of the role of
the Hot Spot in PCB migration.

EPA has documented fishing that occurs in the Fishing Closure
Areas within Buzzards Bay (Greater New Bedford Health Effects
Study, 1987) . EPA believes that many of the species studied in
order to assess public health risks are exposed to contaminants
on a site-wide basis, since these fish may move throughout the
Site. Because the Hot Spot serves as a source of contamination
to the entire Site, and because certain biota may travel
throughout the Site, it is necessary and appropriate to consider
the levels of contamination within biota on a site-wide basis for
determining public health and environmental risks posed by the
Hot Spot.

Data collected by the Massachusetts Department of Marine
Fisheries from Area III between 1980 and 1986, in accordance with
FDA protocol, confirm that the FDA 2 ppm limit in lobsters
(Figure 10) continues to be exceeded. Additional biota data,
including that generated by Pruell, et al. (1988) and the
Massachusetts Division of Marine Fisheries (1987), also
demonstrate that the FDA tolerance level continues to be
exceeded.
13
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Data obtained in 1987 that show PCS concentrations in the edible
portions of lobster, winter flounder, and clams are presented' in
Table 1. The biota were collected from areas that correspond to
the DPH Fishing Closure Areas. The concentrations of PCBs in the
lobster do not include concentrations from the tomalley, the
lobster's liver, where PCBs tend to bioaccumulate. in order to
be consistent with the FDA protocol requiring the tomalley be
included as part of the edible portion determination in lobsters,
EPA estimated the total edible tissue PCB concentration for a
typical lobster from Area II. in so doing, EPA predicted a
significant increase in the PCB concentration (i.e., from
0.46 ppm to 2.3 ppm). This methodology is provided on page 2-33
of the Baseline Public Health Risk Assessment.
VZ. SUMMARY OF SITE RISKS
A. General Feasibility Study and Risk Assessment
Information

In the feasibility study process, remedial alternatives are
developed that protect human health and the environment by
recycling waste or by eliminating, reducing, and/or controlling
risks posed by a site through each exposure pathway. The number
and type of alternatives to be analyzed shall be determined at
each site, taking into account the scope, characteristics, and
complexity of the site problem that is being addressed/ In
developing and, as appropriate, screening the alternatives,
remedial action objectives are developed by. specifying
contaminants and media of concern, potential exposure pathways,
and remediation goals. Initially, preliminary remediation goals
are developed based on readily available information, such as
chemical-specific ARARs or other reliable information.
Preliminary remediation goals are modified, as necessary, as more
information becomes available during the RI/FS. Final
remediation goals are determined when the remedy is selected.
Remediation goals establish acceptable exposure levels that are
protective of human health and the environment and are developed
by considering applicable or relevant and appropriate
requirements under federal and state environmental regulations,
if available, and the following factors:

1. For systemic toxicants (i.e., an agent that kills or
injures animal or plant systems), acceptable exposure
levels shall represent concentration levels to which
the human population, including sensitive subgroups,
may be exposed without adverse effect during a
lifetime or part of a lifetime, incorporating an
adequate margin of safety.
14
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2. For known or suspected carcinogens (i.e., causes or
contributes to the production of cancer), acceptable
exposure levels are generally concentration levels
that represent an excess upper bound lifetime cancer
risk to an individual of between 10" and 10"6 (an
additional 1 in 10,000 to a 1 in 1,000,000 chance of
the event occurring) using information on the
relationship between dose and response. The 10"6
risk level shall be used as the point of departure
for determining remediation goals for alternatives
when ARARs are not available or are not sufficiently
protective because of the presence of multiple
contaminants at a site or multiple pathways of
exposure.

3. Factors related to technical limitations such as
detection/quantification limits for contaminants.

4. Factors related to uncertainty.

5. Other pertinent information.

B. Contaminants of Concern

EPA performed a Baseline Public Health Assessment to estimate the
probability and magnitude of potential adverse human health
effects from exposure to contaminants associated with the Site.
The four contaminants of concern for the Site include PCBs and
the heavy metals cadmium, copper and lead. These contaminants
were selected from the contaminants present at the Site on the
basis of frequency of detection, concentration and quantity of
contaminant within the Site, environmental mobility, and route-
specific toxicity, as specified in the Superfund Public Health
Evaluation Manual. PCBs are included on EPA's list of hazardous
substances under CERCLA, and PCBs are regulated under the Toxic
Substances Control Act (TSCA). EPA has classified PCBs as a
probable human carcinogen (B2 classification) based on the
inducement of malignant liver tumors in rodents in five studies.
In addition, there is suggestive evidence of excess risk of liver
cancer in hunans by ingestion and inhalation and/or dermal
contact. Refer to Section 3 of the Responsiveness Summary for a
more complete discussion of PCB toxicity.

Historically, EPA and the State focused on PCBs because of
bioaccunula'tlon in the commercial fishing grounds to levels in
excess of the FDA's tolerance limit in New Bedford Harbor. The
FDA tolerance limit is not solely health-based. As such, the
potential risks associated with consumption of biota with PCB
concentrations below the FDA limit may still present risk greater
than EPA's target risk range of 10"4 to 10"6.
15
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C. Public Health Risks/Human Health Evaluation

EPA developed several hypothetical exposure scenarios in order to
estimate quantitatively the potential human health effects
associated with the contaminants of concern. The exposure
scenarios reflect the characteristic uses and location of the
Site. Incremental lifetime cancer risks and the potential for
noncarcinogenic adverse health effects were estimated for the
various exposure scenarios. Based on the results of a screening
process designed to identify pathways of exposure, EPA selected
direct contact and incidental ingestion of shoreline sediment and
ingestion of aquatic biota as the exposure pathways of concern.
Consistent with EPA guidance, the public health risk assessment
assumes that institutional controls are not effective in
preventing the ingestion of biota from the Harbor. For New
Bedford Harbor, this assumption is substantiated by interviews
conducted by the Massachusetts Department of Public Health (1987)
with local residents which revealed that persons consume locally
caught seafood with varying degrees of frequency.

Potential noncarcinogenic and carcinogenic risks from exposure to
PCBs by direct contact and incidental ingestion of sediment from
selected areas of the Estuary, including the Hot Spot Area are
presented in Table 2. The corresponding area of exposure is
illustrated in Figures 4 and 11. Locations within the Hot Spot
Area that were evaluated in the Risk Assessment are accessible to
both children and adults. For the risk calculation, EPA used a
PCB concentration at a location directly on the shoreline, and
assumed that a child (age 6 to 16) would be exposed. This
shoreline location, identified on Figure 4, contains a PCB
concentration of 9,923 ppm. Based on the direct contact hazard
presented by the highly contaminated sediment in the Hot Spot
Area, significant public health risks are expected under the
assumed conditions of exposure.

In addition to direct contact and incidental ingestion of Hot
Spot sediments, EPA examined potential risks from the ingestion
of biota on a site-wide basis. These estimates were calculated
on the basis of consumption of lobster, winter flounder and
clams. EPA estimated risks based on consumption of one fish meal
per day, par week, and per month, with a fish meal consisting of
an 8-ounce portion for older children and adults and a 4-ounce
portion for younger children. The potential carcinogenic risks
with their corresponding exposure concentrations are presented in
Table 3. Table 3 indicates that monthly consumption of biota
contaminated below the FDA limit of 2 ppm results in a public
health risk greater than EPA's target risk range.

The concentrations used in this evaluation are from biota caught
in the Buzzards Bay portion of the Site, within Area II of the
Fishing Closure Areas. The consumption of contaminated biota

16
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presents a public'health risk under the assumed conditions of
exposure. The EPA believes the assumed exposure scenarios to be
a reasonable estimate, since the risks were based on consumption
of biota from the Bay portion of the Site, where documented
fishing occurs.

A more complete discussion of Site risks can be found in the Hot
Spot FS on pages 3-1 through 3-8 and in the Public Health Risk
Assessment.
D. Ecological Risk

EPA is presently conducting a Baseline Environmental Risk
Assessment as part of the overall Feasibility Study for the
Estuary and Lower Harbor and Bay Areas. EPA is also examining
sediment clean up goals for the protection of aquatic organisms
as part of this study. This study is scheduled to be completed
in June 1990. For the Hot Spot Operable Unit, the EPA examined
potential risks to marine biota due to exposure to PCB
contamination in the Hot Spot sediment and in the water column.
The extremely high contaminant levels in Hot Spot surface
sediment precludes benthic invertebrates and fish from thriving
in this area.

Contamination of aquatic biota in New Bedford Harbor occurs
through exposure to contaminated sediments and surface water, and
the ingestion of contaminated food. While the PCB exposure that
biota receive via direct contact with the Hot Spot sediment and
the overlying water column is important, the role the Hot Spot
plays in the migration and subsequent exposure on a site-wide
basis is also of importance.
VII. DOCUMENTATION OF NO SIGNIFICANT CHANGES
EPA adopted a Proposed Plan for remediation of the Hot Spot on
August 3, 1989. The preferred alternative, specified in the
Proposed Plan, included the following major provisions:

dredging of 10,000 cubic yards of contaminated
sediments;
dewatering of the sediments in the pilot study area
using the existing Confined Disposal Facility (CDF);
treatment of the dredged sediments utilizing an on-
site incinerator; and
stabilization of the treated sediment to immobilize
metals, if a leaching test indicates it is needed.
.*
EPA will conduct pre-design studies, a normal component of most
engineering design projects, to evaluate and select the unit

17
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process equipment. These studies will focus on ensuring
compliance with ARARs specific to this action identified in
Section XI.B of this document.

VIZI. DEVELOPMENT AMD SCREENING OF ALTERNATIVES

A. Statutory Requirements/Response Objectives

Prior to the passage of the Superfund Amendments and
Reauthorization Act of 1986 (SARA), actions taken in response to
releases of hazardous substances were conducted in accordance
with CERCLA as enacted in 1980 and the revised National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR
Part 300, dated November 20, 1985. Until the revised NCP to
reflect SARA becomes effective, the procedures and standards for
responding to releases of hazardous substances, pollutants and
contaminants shall be in accordance with Section 121 of CERCLA
and to the maximum extent practicable, the current NCP.

Under its legal authorities, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that are
protective of human health and the environment. In addition,
Section 121 of CERCLA establishes several other statutory
requirements and preferences, including: a requirement that EPA's
remedial action, when complete, must comply with applicable or
relevant and appropriate environmental standards established
under Federal and state environmental laws unless a statutory
waiver is warranted; a requirement that EPA select a remedial
action that is cost-effective and that utilizes permanent
solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable; and a
statutory preference for remedies that permanently and
significantly reduce the volume, toxicity or mobility of
hazardous wastes over remedies that do not achieve such results
through treatment. Response alternatives were developed to be
consistent with these Congressional mandates.

EPA analyzed a number of potential exposure pathways for risk and
threats to public health and the environment in the Hot Spot
Feasibility Study and in the Baseline Public Health Risk
Assessment. EPA used guidelines in the Superfund Public Health
Evaluation Manual regarding development of design goals and risk
analyses for remedial alternatives in the development of response
actions. As a result of these assessments, EPA developed
remedial response objectives to mitigate existing and future
threats to public health and the environment. These response
objectives are:
18
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1. Significantly reduce PCB migration from the Hot Spot
area sediment, which acts as a PCB source to the
water column and to the remainder of the sediments in
the harbor.

2. Significantly reduce the amount of remaining PCB
contamination that would need to be remediated in
order to achieve overall harbor clean-up.

3. Protect public health by preventing direct contact
with Hot Spot sediments.

4. Protect marine life by preventing direct contact with
Hot Spot sediments.

B. Technology and Alternative Development and Screening

The term "technology" refers, in general, to a category of
remedial action activity, such as, chemical treatment or capping.
Early in the process of finding an appropriate remedy for a site,
EPA screens or reduces the universe of potentially applicable
technologies by evaluating the technologies in terms of their
technical implementability. EPA then combines remaining
technologies into remedial alternatives, which are developed and
subsequently screened on the basis of the following three
criteria.

1. Effectiveness. This criterion focuses on the degree
to which an alternative reduces toxicity, mobility,
or volume through treatment, minimizes residual risks
and affords .long-term protection, complies with
ARARs, minimizes short-term impacts, and how quickly
it achieves protection. Alternatives providing
significantly less effectiveness than other, more
promising alternatives may be eliminated.
Alternatives that do not provide adequate protection
of human health and the environment are eliminated
from further consideration.

2. Implementability. This criterion focuses on the
technical feasibility and availability of the
technologies each alternative would employ and the
administrative feasibility of implementing the
alternative. Alternatives that are technically or
administratively infeasible or that would require
equipment, specialists, or facilities that are not
available within a reasonable period of time may be
eliminated from further consideration.
19
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3. Cost. The costs of construction and any long-term
costs to operate and maintain the alternatives shall
be considered. Costs that are grossly excessive
compared to the overall effectiveness of alternatives
may be considered as one of several factors used to
eliminate alternatives. Alternatives providing
effectiveness and implementability similar to that of
another alternatives by employing a similar method of
treatment or engineering control, but at greater
cost, may be eliminated.

CERCLA, the NCP, and EPA guidance documents including/ "Guidance
on Feasibility Studies Under CERCLA1* dated June 1985, and the
"Interim Guidance on Superfund Selection of Remedy" (EPA Office
of Solid Waste and Emergency Response [OSWER] Directive No.
9355.0-19) dated December 24, 1986 set forth in detail the
process by which EPA evaluates and selects remedial actions. In
accordance with these requirements and guidance documents, EPA
developed treatment alternatives for the Site ranging from an
alternative that, to the degree practicable, eliminates the need
for long-term management (including monitoring) at the Site to
alternatives involving treatment that reduce the mobility,
toxicity, or volume of the hazardous substances as their
principal element. In addition to the range of treatment
alternatives, EPA developed a containment option involving little
or no treatment and a no-action alternative in accordance with
Section 121 of CERCLA.
t

Section 121(b)(1) of CERCLA presents several factors that at a
minimum EPA is required to consider in its assessment of
alternatives. In addition to these factors and the other
statutory directives of Section 121, the evaluation and selection
process was guided by the EPA documents "Additional Interim
Guidance for Fiscal Year 1987 Records of Decision" dated July 24,
1987 and "Interim Final Guidance on Preparing Superfund Decision
Documents" (OSWER Directive No. 9355.3-02) dated June 1989.
These documents provide direction on the consideration of SARA
cleanup standards and set forth nine evaluation criteria that EPA
should consider in its evaluation and selection of remedial
actions. The nine evaluation criteria are:

Threshold Criteria

1. Overall protection of human health and the
environment.

2. Compliance with applicable or relevant and
appropriate requirements (ARARs).

Balancing Criteria

3. Long-term effectiveness and permanence.

20
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4. Reduction of toxicity, mobility or volume through
treatment.

5. Short-term effectiveness.
--^
6. Implementability.

7. Cost.

Modifying Criteria

8. State/support agency acceptance.

9. Community acceptance.

Chapter 5 of the Hot Spot Feasibility Study identified, screened
and evaluated technologies based on engineering feasibility,
implementability, effectiveness, and technical reliability.
Chapter 6 of the Hot Spot Feasibility Study presented the
remedial alternatives developed by combining the technologies
identified in the previous screening process in the categories
required by OSWER Directive No. 9355.0-19. The purpose of the
initial screening was to narrow the number of potential remedial
actions for further detailed analysis while preserving a range of
options. Each alternative we> then evaluated and screened in
Chapter 7 of the Feasibility Jtudy. In summary, of the, nine
remedial alternatives screened in Chapter 6, four were retained
for detailed analysis. Table 4 identifies the four alternatives
that were retained through the screening process, as well as
those that were eliminated from further consideration.
IX. DESCRIPTION/SUMMARY OF THE DETAILED ANALYSIS OF
ALTERNATIVES

A brief discussion of capping as an alternative for the Hot Spot
is included here to provide the reasoning why this alternative
was not carried into detailed analysis for the Hot Spot. Refer
to Section 7 of the Responsiveness Summary for a more complete
discussion of capping for the Hot Spot.

A. Capping Alternative for the Hot Spot

The identification and initial screening of remedial technologies
conducted in 1986-87 identified capping as a potentially
applicable containment (or non-removal) technology in each of the
Site's three geographical study areas: the Hot Spot, the Estuary,
and the Lower Harbor and Bay. Two other containment technologies
were also identified: impermeable synthetic membranes and

21
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chemical sealants. As a result of the subsequent screening step,
which considered effectiveness, feasibility, and
implementability, EPA retained capping for further evaluation.

During 1987, EPA conducted a detailed evaluation of capping as a
remedial technology. EPA evaluated capping based on three major
criteria: effectiveness (including technical reliability and
potential impacts to public health and the environment);
implementability (including technical, institutional, and
administrative feasibility of installing, monitoring and
maintaining a cap); and cost. Because capping satisfied these
three criteria, EPA retained capping as an applicable technology
for all three geographical study areas of the Harbor.

EPA combined remedial technologies retained from the screening
process into complete remedial alternatives for each of the three
study areas during 1987-88. In accordance with the amendments to
CERCLA which require consideration of on-site containment
alternatives, EPA developed a capping alternative for the Hot
Spot. This alternative consisted of installing an embankment
around the Hot Spot, stabilizing the sediment, and installing a
synthetic cap over the Hot Spot Area.

EPA then screened all of the remedial alternatives for the Hot
Spot based on the effectiveness, implementability and cost
criteria. At this step, in accordance with EPA guidance on
screening of remedial alternatives, evaluation under the
effectiveness criterion requires the inclusion of consideration
of the alternative's ability to meet ARARs and its long-term
reliability. As a result of this screening step, EPA eliminated
the capping alternative because, in EPA's judgment, the long-
term effectiveness of the cap for the Hot Spot sediment was
uncertain. The lack of information to substantiate the
appropriate thickness and effectiveness of a cap over sediment
that contains extremely high levels of PCBs such as those found
in the Hot Spot, contributed to the elimination of capping in the
remedial alternative screening process.

EPA was concerned about the inability of the cap to provide a
permanent barrier to migration of highly contaminated sediment.
EPA considers breaching of the cap likely in the Hot Spot Area,
since capping this area would increase accessibility by creating
an upland area. In the event of failure, highly contaminated
sediment that has not diminished in toxicity or volume would
contaminate cap material, increasing the volume of contaminated
material, and would migrate throughout the Site.

The implementation problems likely to be encountered with a
capping alternative also contributed to EPA's decision to screen
out capping for the Hot Spot. The difficulty in installing an
embankment around the Hot Spot to allow for installation of the
cap, as well as the difficulty in deploying the cap itself,

22
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because of the poor sediment stability, indicated that capping
was not an appropriate alternative for the Hot Spot.

Finally, capping the highly contaminated Hot Spot sediment is not
appropriate because of the levels of contamination that would
remain. EPA is currently evaluating capping as an alternative
for the Estuary, excluding the Hot Spot, and has retained capping
as a viable alternative for portions of the Lower Harbor and Bay.

B. Summary of the Detailed Analysis of Alternatives

This section presents a narrative summary and brief evaluation of
each alternative according to the evaluation criteria described
above. A detailed tabular assessment of each alternative is
presented in Table 5.

The alternatives analyzed for the Hot Spot include a non-removal
alternative (Hot Spot [HS]-1) and three removal alternatives (HS-
2, HS-3, HS-4).

Non-Removal Alternative
Alternative Hot Spot (HS)-l; Minimal No Action

This alternative would involve no remedial action on any of
the contaminated sediments in the Hot Spot. This
alternative would, however, entail restricting Site access
to the west, north and south by installing chain-link
fences to ensure that there would be no access to the Hot
Spot Area via the adjacent shoreline. Limiting access to
the Hot Spot Area would limit the potential for direct
contact with contaminated sediments. In addition to
warning signs currently posted on the eastern and western
shorelines, additional warning signs regarding swimming,
fishing and shellfish harvesting restrictions would be
posted along the western shoreline. Annual sediment and
surface water sampling and analysis of PCB and heavy metal
levels would be conducted.

Under this alternative, contaminants would continue to
migrate from the Hot Spot Area to the Estuary and Lower
Harbor. This alternative is readily implementable and
provides short-term effectiveness in protecting public
health, but would not protect the environment from risks
posed by contaminated sediments. This alternative would
not provide overall protection of human health and the
environment and would not result in reduction in PCB
levels. This alternative would not reduce the toxioity,
mobility, or volume of contaminants in Hot Spot sediments.
The Minimal No Action alternative would not provide a long-

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term permanent remedy that would reduce the nature and
magnitude of risk to public health and the environment
within the New Bedford Harbor Site since the Hot Spot Area
would continue to serve as a source of PCBs to the Estuary
and Lower Harbor/Bay. EPA evaluated this alternative in
detail in the FS to serve as a comparison to other remedial
alternatives under consideration.

Estimated Time for Implementation: less than 1 year
Estimated Direct Capital Cost: $35,000
Estimated Indirect Capital Cost: $13,000
Estimated Operation & Maintenance Cost: $407,000
Estimated Time for Operation: 30 years of
maintenance
Estimated Total Cost: $455,000

Removal Alternatives

After the screening procedure, EPA retained three alternatives
(HS-2, HS-3 and HS-4) that require removal of contaminated Hot
Spot sediments for detailed evaluation. EPA used results of the
EPS and the Pilot Study to examine the dredging, treatment,
disposal and monitoring techniques proposed for each of these
three alternatives. EPA determined that a substantial reduction
in cleanup costs would result from use of the existing Pilot
Study area to support the treatment operations being considered.
All of the removal alternatives considered in the FS make use of
this area (Figure 12).

All three removal alternatives contemplate excavation of
approximately 10,000 cubic yards of contaminated sediments at
depths up to four feet using dredging equipment, and
transportation of the dredged material by a floating hydraulic
pipeline (approximately 1 mile long) to the Pilot Study area.
After settling, sediments would be pumped to a nearby secondary
facility for dewatering using a filter-press unit. Effluent from
the dewatering process would be treated to remove PCBs and heavy
metals prior to discharge back into the harbor. Sediment
treatment techniques differ in each alternative and are described
in detail below.

Alternative HS-2; Incineration

EPA has selected this alternative to address the Hot Spot
Area of the Site. It is discussed in Section X entitled
"Description of Selected Remedy" on pages 26 through 32.

Alternative HS-3; Solidification/Disposal

In this alternative, contaminated sediments would be
dredged and dewatered, and on-site solidification of the

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dewatered sediment would be conducted to immobilize PCBs
and heavy metals. The solidified material would be
transported to an off-site Federally-approved landfill for
disposal.

Solidification combined with disposal of sediments in a
secure landfill would reduce the mobility of PCBs and
metals. However, solidification would increase the volume
of contaminated sediment, and its effectiveness on
extremely high levels of organic contamination is
uncertain. Solidification would not reduce the toxicity of
contaminants in the sediments. This alternative would
provide short-term effectiveness and is implementable,
provided an off-site disposal facility is available. Off-
site disposal of contaminated sediments in an approved
landfill would provide long-term protection of human health
and the environment. This alternative would provide
significant progress toward overall protectiveness of
public health and the environment since it would result in
the removal of approximately 48 percent of the PCBs in the
Estuary.

Estimated Time for Remediation: - 1 year
Estimated Direct Capital Cost: $9,738,500
Estimated Indirect Capital Cost: $3,561,700
Estimated Total Cost: $13,300,200
Alternative HS-4; Solvent Extraction

In this alternative, contaminated sediments would be
dredged and dewatered, and solvent extraction would be used
to treat the contaminated sediment. After the treatment
process, tank trucks would transport the PCB-enriched
solvent extract to an off-site federally-approved facility
for incineration. Solidification of remaining waste
material would be used to immobilize metals prior to
storage in the CDF.

Solvent extraction is an innovative technology, a specific
version of which was demonstrated at the Site during the
Pilot Study. This technology, combined with incineration
of the solvent and solidification of the treated sediment,
would significantly reduce the mobility, toxicity, and
volume of PCB-contaminated sediment. This alternative
would provide significant progress toward overall
protectiveness of public health and the environment because
it would remove 96 to 99 percent of the PCBs from the Hot
Spot sediments. Preliminary tests indicate some reduction
in the mobility of metals. Because solvent extraction is
an innovative technology, additional testing would be
required to demonstrate its effectiveness on highly

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contaminated sediment. Concerns remain over the
reliability of this technology for the levels of
contamination of the Hot Spot sediment and the higher
residual concentrations that may remain after treatment
(i.e., 96 to 99% reduction versus 99.9999% reduction with
incineration). This alternative would provide long-term
effectiveness because it would permanently treat PCB
contamination, and the technology appears to reduce the
mobility of heavy metals.

Estimated Time for Remediation: 1 year
Estimated Direct Capital Cost: $7,806,350
Estimated Indirect Capital cost: $4,362,300
Estimated Total Cost: $12,168,650
X. THE SELECTED REMEDY

The selected remedial action for the New Bedford Harbor Site/Hot
Spot Area consists of source control measures.

A. Description of the Selected Remedy

1. Remedial Action Objectives

The selected remedy was developed to satisfy the following
remedial objectives. These objectives will guide the design of
the remedy, and they will be used to measure the success of the
remedy.

Significantly reduce PCB migration from the Hot Spot
area sediment, which acts as a PCB source to the
water column and to the remainder of the sediments in
the harbor.

Significantly reduce the amount of remaining PCB
contamination that would need to be remediated in
order to achieve overall harbor clean-up.

Protect public health by preventing direct contact
with Hot Spot sediments.

Protect marine life by preventing direct contact with
Hot Spot Area sediments.

2. Description of Remedial Components

The source control remedial measures include:
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Dredging. Approximately-10, 000 cubic yards of contaminated
sediments will be removed using a dredge. Dredging will
occur in the Hot Spot Area at depths of up to four feet to
remove sediments with PCB concentrations of 4,000 ppm or
greater.

Contaminated sediments will be excavated using a small
cutterhead dredge. EPA recommended this type of dredge for
use in the Hot Spot Area based on results of the Pilot
Study conducted by the Corps of Engineers. This study
demonstrated that the cutterhead dredge minimizes sediment
resuspension and subsequent migration of contaminated
sediments. The Corps of Engineers developed operational
procedures for the dredge that will be followed to ensure
dredging efficiency.

In addition to using the controls examined in the pilot
study which were effective, as an added protective measure,
EPA will examine other control options during the design
phase, such as physical barriers (floating booms and silt
curtains) to formulate appropriate control options for the
dredging process to minimize and control sediment
resuspension.

Transportation and Dewatering. The dredged sediments will
be transported to the Pilot Study cove area by a floating
hydraulic pipeline, where the sediments will be dewatered.
Dewatering of sediments will increase the efficiency of the
incinerator. Effluent resulting from the dewatering
process will be treated to reduce PCBs and heavy metals
using best available control technology prior to discharge
back into the harbor.

During design, EPA will determine the proper procedures
necessary to ensure that use of the CDF in the dewatering
process will comply with the State hazardous and solid
waste requirements (e.g., permeability standards).

As a part of the design phase, incineration technologies
will be carefully examined to determine the optimum
equipment configuration and incinerator operating
parameters for the Hot Spot sediment. This examination
will include conducting a test burn on the Hot Spot

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sediment, to assist in the development of plans and
specifications for treating the material specific to this
Site.

Stabilization. Incineration of PCB-contaminated sediment
will produce residual ash. Following incineration, the
Toxicity Characteristic Leaching Procedure (TCLP) test will
be performed on the ash to determine if it exhibits the
characteristic toxicity and is, therefore, considered a
hazardous waste under the Resource Conservation and
Recovery Act (RCRA). If the TCLP test reveals that the ash
is a RCRA hazardous waste, the ash will be solidified such
that metals no longer leach from the ash at concentrations
that exceed the standards set forth for determining the
toxicity of a material.

EPA investigated the technical feasibility of applying
solidification/stabilization technology to New Bedford
Harbor sediment in laboratory studies as a part of the EPS.
Several processes were examined, and physical and chemical
tests were conducted on the material. Additional testing
will be conducted during the design process to tailor a
solidification process for the treated Hot Spot sediment
(ash) and to determine the material's chemical
characteristics after treatment.

During remedial activities, (solidified) ash will be
temporarily stored in an area adjacent to the CDF,.
Following completion of these activities, the (solidified)
ash will be stored in the secondary cell of the CDF and
covered. Storage of the treated material will comply with
the solid waste requirements. Ultimate disposition of this
material will be addressed in the second operable unit for
the Site.

Estimated Time for Remediation: 1 year
Estimated Direct Capital Cost: $9,143,700
Estimated Indirect Capital Cost: $5,235,600
Estimated Total Cost: $14,379,300

B. Comparative Analysis and Rationale for Selection

The rationale for choosing the selected alternative is based on
the assessment of the ability of the alternatives retained for
detailed evaluation to satisfy each of the nine evaluation
criteria mention above in Section VIII.B of this document. To
reiterate, the evaluation criteria are:

1. Overall protection of human health and the
environment.
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2. Compliance with applicable or relevant and ,,;.
appropriate requirements (ARARs).

3. Long-term effectiveness and permanence.

4. Reduction of toxicity, mobility or volume through
treatment.

5. Short-term effectiveness.

6. Implementability.

7. Cost.

8. State/support agency acceptance.

9. Community acceptance.

The first two criteria are threshold determinations that must be
satisfied in order for an alternative to be eligible for
selection. To evaluate the overall protectiveness of an
alternative, EPA focuses on how the specific alternative achieves
protection over time, if at all, and how site risks are reduced.
To evaluate whether an alternative is able to comply with ARARs,
EPA considers whether, after the remedial action specified in the
alternative is implemented, applicable or relevant and
appropriate requirements under federal and state environmental
laws are achieved. EPA may also consider whether a waiver of any
ARAR is warranted.

EPA uses the next five criteria, the balancing criteria, to weigh
the major tradeoffs among alternatives. In evaluating the long-
term effectiveness and permanence of an alternative, EPA
considers the degree of certainty that the alternative will
attain the response objectives, the magnitude of residual risk
caused by untreated waste or treatment residuals remaining at the
conclusion of the remedial activities, and the adequacy and
reliability of controls that are necessary to manage treatment
residuals and untreated waste. EPA also considers the potential
impacts on human health and the environment should the remedy
need replacement.

In evaluating alternatives under the reduction of toxicity/
mobility, or volume of contaminants through treatment criterion,
EPA considers the treatment process used and the materials
treated, the amount of hazardous materials destroyed or treated,
the degree of expected reductions in toxicity, mobility or
volume, and the type and quantity of residuals remaining after
treatment.
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To determine how an alternative satisfies the short-term
effectiveness criterion, EPA considers the impacts on the
community and the environment during the construction and
implementation phases of the remedial actions and the time
required until the remedial objectives are achieved.

The ease or difficulty of implementing an alternative is assessed
by considering its technical and administrative feasibility, and
the availability of services and materials. Costs assessed under
the cost criterion include capital costs, annual operation and
maintenance costs, and present worth costs.

The final two criteria, state and community acceptance, the
modifying criteria, are generally taken into account after EPA
has received public comment on the RI/FS and the Proposed Plan.

Alternative HS-2 (Incineration) is protective of human health and
the environment. The removal of PCBs from the Hot Spot Area and
subsequent destruction by incineration will permanently reduce
the mobility, toxicity, and volume of the PCBs. Public health
and environmental risks directly associated with the Hot Spot
will be significantly reduced. Removal of the Hot Spot will also
serve to reduce PCBs affecting the remainder of the Site.

Incineration is technically feasible and has been proven to be an
effective technology for the destruction of organics, including
PCBs at levels similar to those in Hot Spot Area sediment.
Mobile incineration units capable of treating 75 tons of sediment
per day are currently available. Moreover, incineration systems
are highly reliable because of the proven technology employed and
the degree of monitoring and control practiced.

Table 5 presents a comparative summary of the four remedial
alternatives that were carried through detailed analysis. A
narrative discussion of EPA's evaluation of these alternatives
under the evaluation criteria appears below.

Of the four alternatives, HS-1 (Minimal No Action), does not
satisfy the threshold criterion of being protective of human
health and the environment. Therefore, it cannot be selected as
the remedial alternative for the Hot Spot sediments.
Nevertheless, it provides a useful yardstick for comparison for
the other alternatives.

Alternatives HS-2 and HS-4 (Solvent Extraction) would provide the
greatest long-term effectiveness and permanence among the
alternatives, because they both involve the ultimate destruction
of PCBs. However, the reliability of HS-2 is higher than that of
HS-4, since solvent extraction is a less certain method of
treatment than is incineration for the high concentrations of
PCBs found in the Hot Spot sediment. In contrast to these two
alternatives, HS-3 (Solidification) would only immobilize the

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PCBs, and its effectiveness on extremely high levels of organic
contamination is uncertain, especially over a long period of
time. Alternative HS-1 would not destroy, immobilize, or remove
the PCBs. They would continue to provide a source of
contamination to the rest of the harbor and continue to pose
significant risk from direct contact in shoreline areas.

Alternatives HS-2 and HS-4 also would provide the greatest
reduction in mobility, toxicity, and volume among the
alternatives. Alternative HS-2 provides for removal of a greater
percentage of all PCBs from the sediment, 99.9999%, as compared
to 96 to 99% removal of the PCBs by Alternative HS-4, a
significant difference at the levels of contamination found in
the Hot Spot. While HS-3 would reduce the mobility of the PCBs
in the Hot Spot sediment, the volume of the contaminated material
would increase. Alternative HS-1 would provide no reduction in
toxicity, mobility, or volume.

Alternatives HS-2, HS-3, and HS-4 are not distinguishable in
terms of their short-term effectiveness, and each can be
implemented in approximately one year. Each of these
alternatives would employ dredge controls and air quality
controls to minimize and control resuspension of sediments and
releases of contaminants. However, some additional risk to
workers may arise under these three removal alternatives during
the treatment process since the contaminated sediments are being
removed and treated. These risks may be minimized through
training in the proper use and operation of safety equipment.
EPA does not believe that the three alternatives would pose
significant risk to the public because the contemplated control
options have proven to be effective. Alternative HS-1 would have
minimal short term effectiveness since minimal action would be
taken.

Alternative HS-1 would be the simplest alternative to implement
because it would involve minimal construction with no removal or
treatment activities. Both HS-2 and HS-4 would require testing
to verify treatment and to determine the need for solidification
of residuals. While treatability testing in the form of a test
burn would need to be conducted for HS-2, this testing would be
for the purpose of determining optimum equipment configuration
and operating parameters, and is not needed to determine
effectiveness. Solvent extraction is an innovative technology.
Thus, under HS-4, in addition to testing required to establish
operating parameters, pilot studies would be required to
initially determine the efficacy of the process on the highly
contaminated Hot Spot sediment. Transportation of the PCB-
solvent enriched extract to a federally-approved off-site
incinerator is an implementation problem_not_found—in HS-2.
t
Both HS-2 and HS-4 would require special equipment and operators.
However, the equipment necessary for HS-4 may be more difficult

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to obtain than that necessary for HS-2. Treatability testing
would be required under HS-3, and questions regarding long-term
stability would remain for the high levels of organic
contamination. Additional implementation problems peculiar to
Alternative HS-3, are the necessity of obtaining disposal permits
under RCRA and TSCA and the necessity of transport of the
solidified material over long distances. The nearest disposal
site permitted to accept the contaminated sediment is
approximately 500 miles from New Bedford, and the disposal site's
capacity to accept the contaminated material is not guaranteed.

Alternative HS-1 is the least costly alternative. Alternatives
HS-2, HS-3, and HS-4 have similar costs within the accuracy of
cost estimates for Feasibility Studies.

The primary criteria that differentiate these alternatives are
their long-term effectiveness and permanence and
implementability. Alternative HS-2 satisfies all of the
selection criteria. In contrast, Alternatives HS-3 and 4 fail to
satisfy certain of the selection criteria, or do not satisfy the
criteria with the consistency or performance level of Alternative
HS-2. Since Alternative HS-2 has the highest reliability and
involves relatively few implementation difficulties for the
volume of material to be treated, it provides the best balance of
tradeoffs among the protective alternatives.

EPA considered state and community acceptance of the selected
remedy. The State has concurred in the selection of the remedy..
Community concerns over the selected remedy are focused on the
operation of the incinerator, the impacts of dredging, and
storage of the treated material. EPA believes these concerns are
addressed by specifying compliance with the RCRA and TSCA
incinerator standards, as well as requiring air monitoring to
ensure that all federal and state air standards are attained.
Various monitoring and/or controls will be required during the
dredging operation, which EPA believes will be effective in
minimizing and controlling releases. Additionally, the use of
the CDF and the storage of the treated material will comply with
federal and state requirements. Based upon this assessment,
taking into account the statutory preferences of CERCLA, EPA has
selected this alternative as the remedial approach for the Site.

XI. STATUTORY DETERMINATIONS

The remedial action selected for implementation at the Hot Spot
Area of New Bedford Harbor is consistent with CERCLA and, to the
extent practicable,, the NCP. The selected remedy is protective
of human health and the environment for the Hot Spot Area, and is
cost effective. This interim action will comply with ARARs
specific to this action. However, this interim action will not
attain certain levels or standards of control that might be

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ARARs. This interim remedial action -is only part of a total
remedial action that will attain ARARs when completed. The
selected remedy also satisfies the statutory preference for the
use of treatment which permanently and significantly reduces the
volume, toxicity, or mobility of contaminants as a principal
element. Additionally, the selected remedy utilizes alternative
treatment technologies to the maximum extent practicable. The
Hot Spot contamination represents a principal threat at the New
Bedford Harbor Site and will be treated under the selected
remedy.

A. The selected Remedy is Protective of Human Health and
the Environment

The selected remedy is protective of human health and the
environment for the Hot Spot Area. The remedy for the Hot Spot
will permanently reduce the risks presently posed to human health
and the environment in the Hot Spot area by dredging and treating
the heavily contaminated sediments. Further, by removing
approximately 48% of the mass of the PCBs in the Estuary, these
contaminated sediments will no longer continue to migrate and
contaminate other portions of the Site.

There are no short-term threats associated with the selected
remedy that cannot be controlled with existing, available control
technologies. Incineration is a proven technology for the
destruction of PCBs, and air pollution control devices are
routinely used to meet allowable levels of air emissions.

B. The Selected Remedy Attains ARARs to the Extent
Required by Section 121 of CERCLA

Due to the limited scope of this interim action, standards or
levels of control associated with final cleanup levels will not
be achieved. This action will comply with those ARARs specific
to this interim action. For example, compliance with RCRA
facility and incinerator regulations will be achieved. Chemical-
specific ARARs associated with final cleanup levels (e.g., Water
Quality Criteria and Food and Drug Administration PCB tolerance
level) are not specific to this action and are outside its scope.
ARARs such as these will be addressed by subsequent actions at
the New Bedford Harbor Site.

This interim action is consistent with any planned future actions
because this action calls for the removal of approximately 48
percent of the total PCB mass in sediment from the estuary
portion of the Site, which acts as a continuing source of >
contamination throughout the entire Site. EPA believes that the
implementation of a permanent remedy for the Hot Spot is an

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appropriate and necessary first step toward remediating the
harbor overall. The Hot Spot operable unit is the first step in
the remedial action for the entire Site, which when complete,
will attain all ARARs.

ARARs which are specific to the selected remedial action for the
Hot Spot are:

Toxic Substances Control Act (TSCA)
Resource conservation and Recovery Act (RCRA)
Clean Air Act (CAA)
Clean Water Act (CWA)
Executive Order 11988 (Floodplain Management)
Executive Order 11990 (Protection of Wetlands)
Occupational Safety and Health Administration (OSHA)
310 CMR 30.00 Hazardous Waste Management Requirements
310 CMR 19.00 Solid Waste Management Requirements
310 CMR 6.00 Ambient Air Quality Standards
310 CMR 7.00 Air Pollution Control Regulations
310 CMR 10.00 Wetlands Protection Requirements
314 CMR 4.00 Surface Water Quality Standards
314 CMR 9.00 Certification for Dredging and Filling
314 CMR 12.00 Wastewater Treatment
301 CMR 20.00 Coastal Zone Management
310 CMR 33.00 Employee and Community Right To Know
Requirements

Table 6 lists the ARARs specific to this action, a summary of the
requirement, whether the requirement is applicable or relevant
and appropriate, and the action necessary to attain the ARAR. A
brief narrative summary of the ARARs specific to the selected
remedy follows.

The Toxic Substances Control Act (TSCA), the Resource
Conservation and Recovery Act (RCRA), and the State Hazardous
Waste Management Regulations (310 CMR 30.00) are considered
applicable to the remedial action for the Hot Spot. As such, the
on-site incinerator will be required to operate in accordance
with these requirements. Additionally, remedial activities may
be subject to the Land Disposal Restrictions under RCRA.
Following incineration, the Toxicity Characteristic Leaching
Procedure (TCLP) test will be performed on the ash to determine
if it exhibits the characteristic of toxicity and is, therefore,
considered a hazardous waste under the Resource Conservation and
Recovery Act (RCRA). If this test reveals that the ash is a RCRA
hazardous waste, the ash will be solidified such that metals no
longer leach from the ash at concentrations that exceed the
standards set forth in the requirements, and to comply with the
Land Disposal Restrictions.

The PCB disposal requirements promulgated under TSCA are
considered to be relevant and appropriate for the heavily

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contaminated sediments from the Hot Spot. Under TSCA, soils
contaminated with PCBs at concentrations greater than 50 ppm that
are disposed of after February 17, 1978 must be disposed of in
accordance with 40 CFR Part 761, Subpart D. PCBs may be disposed
of in an incinerator meeting the standards of 40 CFR §761.70, or
in a landfill meeting the requirements of §761.75. Under the
provisions of §761.71(c)(4), the EPA Regional Administrator may
waive one or more of the specified landfill requirements upon
finding that the requirement is not necessary to protect against
an unreasonable risk of injury to health or the environment from
PCBs. Such a waiver is not appropriate for the heavily
contaminated (4,000 ppm and above) Hot Spot sediments being
addressed by this operable unit. Since incineration is selected
as the source treatment technology, treatment and disposal of the
10,000 cubic yards of PCB-contaminated sediment will be in
accordance with the criteria of 40 CFR §761.70. In addition,
disposal of dredged material will be in accordance with 40 CFR
§761.60(a)(5).

Regarding the floodplains, the remedy will comply with Executive
Order 11988 - Protection of Floodplains to the extent
practicable. EPA finds that there is no practicable alternative
to excavation of the contaminated sediments, some of which are
located in the floodplain, since it is the sediments themselves
that are contaminated from the historical disposal and
discharges. Implementation of the remedy will utilize measures
to minimize potential harm to the floodplain. However,
excavation is a temporary disruption, and the design will examine
ways to. minimize this disruption.

Similarly for the wetlands, the remedy will comply with Executive
Order 11990 - Protection of Wetlands, the Clean Water Act Section
404(b)(l) Guidelines, Wetland Protection Requirements (310 CMR
10.00), Certification for Dredge and Fill (314 CMR 9.00), and
Coastal Zone Management (301 CMR 20.00). The Hot Spot sediments
have been affected by the historical disposal and discharges and
act as a continuing source of contamination to the remainder of
the Harbor, and they will be affected by the remedy. These
sediments will be dredged for thermal treatment. EPA finds that
there is no practicable alternative to these actions since it is
the sediments themselves that are contaminated. Implementation
of the remedy will utilize measures to minimize potential harm to
the surrounding areas. The design phase will examine physical
controls, as well as monitoring of the area.

During dredging and treatment of contaminated sediments, air
emissions will be monitored and all applicable or relevant and
appropriate federal and state standards will be attained.
Specifically, the National Ambient Air Quality Standards (NAAQS),
the State Ambient Air Quality Standards (310 CMR 6.00), and the
Air Pollution Control Regulations (310 CMR 7.00) will be met
through specified techniques for the dredging activities, as well

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as required air emission controls and monitoring for the
incinerator, to ensure that health and safety and air quality
requirements are met.

Dewatering of sediments will increase the efficiency of the
incinerator. Effluent resulting from the dewatering process will
be treated to reduce PCBs and heavy metals using best available
technology prior to discharge into the Harbor (314 CMR 4.00 and
314 CMR 12.00). Use of the CDF, whether for dewatering or
storage purposes, will comply with the hazardous and solid waste
regulations (310 CMR 19.00).

During the dredging and treatment of contaminated sediments,
Occupational Health and Safety Administration (OSHA) regulations
will be followed, as well as the Employee and Community Right To
Know Requirements (310 CMR 33.00). In particular, 29 CFR
§1910.120 specifies standards for handling hazardous wastes and
sets allowable ambient air concentrations for activities which
involve release of volatile organic compounds (VOCs) in the
workplace. VOCs are not expected to be a problem during
dredging, since the sediments to be dredged are submerged, and
will then be brought to the CDF area via pipeline for dewatering
prior to incineration. However, air monitoring will be conducted
to ensure that proper health and safety measures are followed.

C. The Selected Remedial Action is Coat-Effective
»

Once EPA has identified alternatives that are protective, EPA
analyzes those alternatives to determine a cost-efficient means
of achieving the cleanup. The costs of the alternatives are
within the +50% to -30% accuracy required for Feasibility Study
estimates.

EPA believes the selected remedy is cost-effective because the
remedy provides overall effectiveness proportional to its costs.
The slightly greater cost of the selected remedy is justified
because the process used in the alternative is more reliable for
the Hot Spot sediments than those called for in the other removal
and treatment alternatives. While the other removal and
treatment alternatives appear to be slightly less expensive, they
do not assure destruction of the high levels of PCBs in the Hot
Spot sediment to the same degree as the selected remedy.
Finally, it is highly probable that additional costs may be
incurred from the need for managing the treatment residuals which
would be derived from the other alternatives.
0. The Selected Remedy Utilizes Permanent Solutions and
Alternative Treatment Technologies or Resource
Recovery Technologies to the Maximum Extent
Practicable

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The selection of treatment for the highly contaminated sediment
is consistent with mandates of CERCLA that highly toxic and
mobile wastes are a priority for treatment, and that treatment is
often necessary to ensure the long-term effectiveness of a
remedy.

Incineration, the principal remedial component of the selected
remedy, is a treatment technology that will provide a permanent
solution to the contaminated sediment problem in the Hot Spot
Area. Dredging of the Hot Spot sediments and treatment by
incineration will reduce the risks posed to public health from
direct contact with contaminated sediments in this area, as well
as address the environmental risks in this area.

Thus, the selected remedy utilizes permanent solutions and
alternative treatment technologies to the maximum extent
practicable, as mandated by statute.

E. The Selected Remedy Satisfies the Preference for
Treatment as a Principal Element

The principal element of the selected source control remedy
consists of removal and on-site incineration of the contaminated
Hot Spot sediments. The selected remedy thus addresses the
principal threat at the Hot Spot Area through the use of a
treatment technology. Therefore, the selected remedy satisfies
the statutory preference for treatment as a principal element
that permanently and significantly reduces the volume, toxicity
or mobility of the hazardous substances.

XII. STATE ROLE

The Massachusetts Department of Environmental Protection (DEP)
has reviewed the various alternatives and fully supports the
selected remedy. The Commonwealth of Massachusetts has also
reviewed this Record of Decision to determine if the selected
remedy will comply with State action-specific ARARs. The
Commonwealth concurs with the selected remedy for the New Bedford
Harbor/Hot Spot Area. A copy of the declaration of concurrence
is attached as Appendix C.
37
-------
FIGURE 1
SITE LOCATION MAP
.Boston
CeggMhattSt

RouafW
North
Dartmouth
38
-------
HOT SPOT
(APPROXIMATE
LOCATION)
ESTUARY
LOWER
HARBOR/BAY
SOUMCI UWS OUACMANOUt:
•»» MOMMO »0"TM » IOUTH HAS*. 1*H ft ltT»
7ZGURB 2
GEOGRAPHICAL STUDY AREAS
39
-------
NEW BEDFORD
AHfeAS

AREA I

APEA II

AREA III
COGGE5HALL -
STREET BRIDGE FAIRHAVEN
WATERS CLOSED TO ALL
FISHING

WATERS CLOSED TO THE
TAKING OF LOBSTERS. EELS.
FLOUNDERS. SCUP. AND TAUT,

WATERS CLOSED TO
LOBSTERING ONLY
SCONTICUT
NECK
DARTMOUTH
WEST
SLAND
CLARKS
POINT
NEW BE
WASTEWATER
TREATMENT
PLANT
OCX
POINT
ILBUR
POINT
KEHSOM'S
POINT
NEGRO LEDGE
APPROXIMATE SCALE
FIGURE 3
FI8HIHQ CLOSURE XREAB
MISAHAUM POINT
40
-------
0 • 50 ppm

J 50 - 500 ppm

500 - 4000 ppm

[ J >4000 ppm (HOT SPOT)
x WETLANDS AREA
FIGURE 4
HOT SPOT SEDIMENT PCB CONCENTRATIONS; 0
- 12 INCHEt
-------
K)
.UM net
FIGURE 5

INTERPRETATION Ol
TOTAL PCB CONCENTRATION
DEPTH: ZERO TO 12 INCHEf
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOf
• SUM Of AVAR.ABLE AHOCMLOR OAI-
-------
>.«.».«.».«.>.»
'i i '» i M
. » . li . n . n
a .
11
.UMfUT
FIGURE 6

INTERPRETATION OF
TOTAL PCB CONCENTRATIONS-
DEPTH: 12 TO 24 INCHES
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOR
• SUM Of AVALABLE AROCHLOR DATA
-------
FIGURE 7

INTERPRETATION OF
TOTAL PCB CONCENTRATIONS'
DEPTH: 24 TO 36 INCHES
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOR
-------
% PCB Mass
FIGURE 8
PCB MASS VERSOS VOLUME
100
80
80
40
20
10,000 cubic yards
0
0
50
100
150
200
250
300
Remediation Voluae, in thousands of cubic yards
-------
SURFACE WATER PCB CONCENTRATIONS
2
-------
o
n
in >»l O
to H- »
a M -o
•a p- r»
M » •
H- H
P H- O
on n «.
M
•O H-
n 9
H- »
P
V)
t- n
u> r* o
•-:
oo r1 o
•^1 O 52
oa in
i/i
cn
\
CD
D
m
u
a.
g.o
e.o
7.0
6.0
5.0

4.0
3.0
2.0
1.0
0.0
79 Q uu.u «».-

— ••

i i

•»
__ , . .

•

'
J
1

i
•

fc
:, BO'.D rir« £r° «3-° B4-° B5-° fl6
YEAR
i

-
-

.0 B7

-------
N
SHCRELNE SEDIMENTS (MUDFLATS)
HOT SPOT AREA

UPPER ESTUARY
COGGESHAU. ST. BRIDGE
- AREA I
- AREA!
PORT PHOEMX BEACH

HURRICANE BAI
PORT RODMAN BEACH
AREA
- AREA ID
4tS»-22
FIGURE 11

LOCATIONS EVALUATED FOR DIREC
CONTACT AND INGESTION EXPOSU
TO CONTAMINANTS IN SEDIMEN
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOR
.48
-------
FIGURE 12
Preferred Alternative for Hot Spot Sediments
General Area
of Hot Spot
Dredging
Pilot Study
Area
Coggeshall St
interstate 195
i
Legend

Hydraulic
Pipeline
Booster
Pump
*******
******\
******\
Acushnet
River
Estuary
49
-------
TABLE 1

CONCENTRATIONS OF TOTAL PCBs (ppm) IN EDIBLE TISSUE OF
BIOTA COLLECTED FROM NEW BEDFORD HARBOR
NEW BEDFORD, MASSACHUSETTS
Species
Area I
Outside of
Area 0' Area m' Closure Areas1
American Lobster2

Mean NC
Maximum NC

Winter Flounder1

Mean 1.039
Maximum 2.629

Clam

Mean 0.689
Maximum 2.121
0.568
1.234
0.371
1.048
0.231
1.181
0.231
0351
0.278
0.825
0.156
0.478
0.064
0.176
0.101
0.340
0.039
0.137
Notes:

1
2
3
NC
Mean
M
Reference:
Areas refer to DPH Fishing Closure Areas.
Lobster concentrations do not include tomaUey.
The edible tissue concentration was estimated using a whole
body/edible tissue ratio of 0.13 (Batelle, 1987).
Not Collected; lobsters were not collected from Area L
Arithmetic mean value of all samples collected.
Maximum value detected in each Area.
"Draft Final Baseline Public Health Risk Assessment," EC Jordan/Ebasco,
1989.
50
-------
TABLE 2

SUMMARY OF RISK ESTIMATES FOR
PCB CONTAMINATED SEDIMENT, DIRECT CONTACT-CHRONIC EXPOSURE'
SEDIMENT PCB
CONCENTRATION (ppm)
NONCARCINOGENIC
RISKS
CARCINOGENIC
RISKS
LOCATION Mean Cone.
Hot Spot2
Upper Estuary1
Lower Estuary1
Cove Area1
9923
378
149
286
Max. Cone.
NA
6393
399
399
Mean Cone.
63
2.4
0.9
1.8
Max Cone
NA
40
2.6
2.6
Mean Cone.
7 x 10 J
3x 10 ••*
1 x 10 A
2x 10-1
Max. Cone.
NA
4 x 10 J
2x 10 ••
2 x 10 *
Notes:
1 Direct Contact exposure for direct contact only. Hypothetical exposure for an older child, age 6-16 over a 10 year
period. Exposure frequency of 20 times per year.
1 Hot Spot concentration from one sample for an area of probable exposure along western shore of the Acushnet River Estuary. (See Figure 4
for location)
1 Exposure locations for Upper Estuary, Lower Estuary and Cove Areas are depicted on Figure 11.

NA = Not Applicable

References: 'Draft Final Hot Spot Feasibility Study0, EC Jordan/Ebasco 1989 and 'Draft Final Baseline Public Health Risk Assessment', EC
Jordan/Ebasco 1989.
-------
TABLES

LIFETIME CARCINOGENIC PUBLIC HEALTH RISKS
INGESTION OF CONTAMINATED BOITA
Source
Lobster2

Flounder

Gam

Notes:
1.
PCB Cone. Frequency of
(ppm2) Exposure
13 Daily
Weekly
Monthly
0.371 Daily
Weekly
Monthly
0.231 Dairy
Weekly
Monthly

All biota concentrations are mean values
Lifetime Risk
(70 years)
7Jx 10 *
1.0 x 10 •*
15xlO'J
1.2 x 10 2
1.7 x 10 '
3.9 xlO-1 '
73 x 10-*
1.1 x 10°
14 x 10"
from the DPH Fishing
Closure Area H
1 Lobster edible tissue includes the tomalley.

Reference;

"Draft Final Baseline Public Health Risk Assessment," EC Jordan/Ebasco,
1989.
52
-------
TABLE 4

SUMMARY OF HOT SPOT ALTERNATIVES

HOT SPOT FEASIBILITY STUDY
NEW DEDFOR!) HARBOR, MASSACHUSETTS
ALTERNATIVE
DEVELOPMENT
(SUBSECTION 6.1)
ALTERNATIVES
ELIMINATED DURING
SCREENING (SUBSECTION 6.3)
ALTERNATIVES REMAINING
FOR DETAILED
EVALUATION
U)
HS-NA-1

IIS-CONT-I
IIS-CONT-2

HS-DISP-1
HS-DISP-2

HS-TREAT-1
US-TREAT-2
US-TREAT-3
IIS-TREAT-4
No-action

Capping
Embankment/Capping

Confined Aquatic Disposal
Out-of-State TSCA/RCRA Disposal

On-site Incineration
Solidification
Solvent Extraction
Off-site Incineration
IIS-NA-1 (IIS-1)
IIS-CONT-1
IIS-CONT-2

IIS-DISP-1
HS-DISP-2
HS-TREAT-A
HS-TREAT-1 (HS-2)
HS-TREAT-2 (IIS-3)
HS-TREAT-3 (IIS-4)
-------
TABLE 5

COMPARATIVE ANALYSIS SUMMARY TAIIX

WIT SPOT FFASIMILITY STINIT
NEW UUFOM) NAHIIUII. MASSACHUSETTS
ASSESSMENT fAC1ORS
ALTF.RNA1 IVF.
HS-I NO-ACTION
ALIERNATIVt:
HS-2 1NCINERA1IUII
SOLIDIFICATION/DISPOSAL
SOLVt'.NC EXIUALTION
• Reduction of Toiiclty,
Mobility, or Volume
• Shorl-tcra Effectiveness

- Tin* Until Protection
it Achieved
Protection of Community
During Remedial Actions
Protection of Workers
During Remedial Actions
- Environmental
No reduction In tosicliy,
•obilily, or volume slice
no tresident I* employed.
Reduction In public health
risk due to direct contact
could He aihievrd in our
month.'' No reduction in
environmental rink.

No Impact In rommnnity dining
remedial art inn.
Minimal rink to worker*
during fenre/»=ign Inslalla-
tion.
No significant adverse
environmental impact from
fence inslal\»\ ion.
Reduction in toiicily ani ing
and repair required.
After sediments have l>een
incinerated and lh«* a:.h
solidified (if needed).
There will be minima I risk
associated with the treated
sediments.

Incineration is a proven
technology; no long-term
management nf treatment
residusls required.
After sediments have been
solidified snd disposed off-
aite, there will be minimal
residual risk.
TSCA/RCKA Isndfill Is a proven
technology; annual monitoring and
maintenance is required.
After sediment.% have lieen
treated and solidified (i
needrd), there will lie
minimal residual risk.
Treatment l>y solvent enti
ion Is cupccted to product
treated sediment that wiI
not need long-term contro
-------
(ronl ilined)
COMPARATIVE ANALYSIS SUMMARY TABLE

HOT SPOT FF.ASIIlll.ITY STUDY
NtW DF.UFUR1) HAKIM HI. MASSACHUSETTS
ASSESSMENT FACTOHS
AI.TFKMAIIVF.
IIS-1 NU-ACTION
ALTERNATIVE
IIS-2 INC I HER AT I OH
SOl.lUinCATION/UISPOSAL
SOLVENT KX1HACTION
in
in
- Heli»liillty of
Control*
Sole reliance on lenrr *inl
institutional control* In
prevent exposure; high Irvel
of residual risk.
Technical Feasibility Fence/signs air easily «<>n-
structpd; envlrniimenlal
monitoring welI-proven.
AdmlnifI rative
Feasibility
Availability of
Services and
Materials
No off-site construction;
therefore, no permits
required.

Services and ontrrials
locally available.
• Cost

- Capital Cost $ 48,QUO
- OMI Cost 401,000
- I'resent Woith Cost *55,tHIO

• Compliance with ARARs/TBCs

- Compliance with ARARs AWJCs will ni>l l>r allai I
Appropriateness of
Waivers
Not JustitiaMr.
Rriaedy will be highly reliable
due to removal of sediment
causing risk.
Incineration would require
special equipment and opera-
tors; treated residuals
would require testing to
verify treatment elfeclive-
nrRi; technology haw lirrn
demonstrated at other sites.
Sane as Alternative IIS- I.
Dredge, drwatering, and mobile
incinerator equipment and
operators needed; available
services in eastern United
Stales.
$14.397.300

14,39?,300
AMJCR will lint be .illainrd.
All other AH Ails will l.r net.
.lust i f iable based on interli
renedy.
Likelihood ol landfill failure is
saall as long as O&H is performed.
TSCA/RCHA Landfill easy to iaiple-
•ent; dewatering and solidification
of sedisuMils proven during bench-
and pilot-scale tests.
Saaw as Alternative IIS-1.
Dredge, dewaierlng, and solidifi-
cation services available in
eastern United Stales. TSCA/
RCRA disposal facility not
locally available.
$13,300,200

13.300,200

Sane as Alternative IIS-2.

Same as Alternative IIS-2.
Sane is Alternative IIS-2.
Solvent extract ion would
rei|uire special e(|iiipmcnt
and operators; treated
residuals would require
testing to verify treatment
ell eel i venesE ; technology I:
been pilot-tested on Hot
Spot sediments.

Same as Al t n u.it ive IIS-I.
Solvent extraction equipment
available Iron vendors bnl
not readily. Eijuipnieiil con
striictlon or pilot-scale
tests oay lie rri|iiireil.
$12.168,650

12,168,650
AWIjCs will not lie all.iinrd
Solvent extraction will un-
to achieve equivalent pri-
fornauce standards.

Same as Alternative IIS-2.
-------
(rnnt
COMPARATIVE ANALYSIS SUIIARY TABU

NOT SPOT FEASIBILITY STUDY
NEW REWORD HARBOR. MASSACHUSETTS
ASSESSMENT FACTORS
AI.TF.HHA1 IVF.
NS-I NU-ACTIUM
ALTERNATIVE
IIS-2 INCINERATION
SULIDIFICATION/UISrOSAL
SOLVENT LXTKACTIUN
- Compliance with
Criteria, Advisories,
and Guidance

Overall Protection of
Human Healtk and tke
Environment

- How Risks are Reduced,
Eliminated, or
Controlled
Uoea not mrr\ FIIA Irvrl lor
Kit in flak and until HO..
la not e*j>ected to achieve FDA
level lor PCIa in lUli and
ahelllisk.
Same aa Alternative IIS-2.
at Alleinalive IIS-2.
Rlaka to pulilir l.r»UI.
reduced by reMrlrHn»
•cccaaf' environment*I ritht
•re not•mitigated.
Riaka to |>ubllc heallli an
-------
TABLE 6

ALTERNATIVE HS-2 ACTION-SPECIFIC ARAR EVALUATION
DREDGING AND ON-SITE INCINERATION OP HOT SPOT SEDIMENT

1. Authority - Federal Regulatory Requirements (FRR)

Requirement
RCRA - General Facility Standards (40 CFR 264.10 - 264.18)

Status
Relevant and Appropriate

Requirement Synopsis
General facility requirements outlining general waste analysis,
security measures, inspections, training, and location standards.

Corresponding Remedial Action(s)
Facility will be constructed, fenced, and operated in accordance
with this requirement. All workers will be properly trained. A
written waste analysis plan must be developed and maintained on-
site. Site entry must be prevented by a 24-hour surveillance
system and appropriate signs posted. A written inspection
program must be developed, and all personnel must complete an on-
the-job training program to ensure facility compliance.

***************
t

2. Authority - FKR

Retirement
RCRA - Preparedness and Prevention (40 CFR 264.30 - 264.37)

status
Relevant and Appropriate

Requirement Synopsis
This regulation outlines requirements for safety equipment and
spill control.

Corresponding Remedial Action(s)
Safety and communication equipment will be installed on-site;
local authorities will be familiarized with the site.

***************

3. Authority - FRR

Requirement .
RCRA - Contingency Plan and Emergency Procedures (40 CFR 264.50
264.56)

57
-------
Status
Relevant and Appropriate

Requirement Synopsis
Every hazardous waste facility must have a contingency plan that
is implemented immediately upon fire, explosion, or release of
harmful hazardous waste constituents.

Corresponding Remedial Action(si
Plans will be developed during remedial design. Copies of the
plans will be kept on-site and will be distributed to the
appropriate persons.

***************

4. Authority - FRR

Requirement
RCRA - Incinerators (40 CFR 264.340 - 264.599)

Status
Applicable

Requirement Synopsis
This regulation specifies the performance standards, operating
requirements, monitoring, inspection, and closure guidelines of
any incinerator burning hazardous waste.

Corresponding Remedial Actiontm)
The transportable ori-site incinerator will be operated in
accordance with the applicable RCRA requirements.

***************

5. Authority - State Regulatory Requirements (SRR)

Requirements
DEP - Hazardous Waste Regulations (310 CMR 30.00)

Status
Relevant and Appropriate

Requirement Synopsis
These regulations specify the Massachusetts requirements for
hazardous waste facilities.

Corresponding Remedial Action(s)
During remedial design, these regulations will be compared to the
corresponding federal RCRA regulations, and the more stringent
requirements will be addressed.
58
-------
6. Authority - SRR

Requirement
DEP - Solid Waste Management Regulations (310 CMR 19.00)

Status
Applicable

Requirement Synopsis
These regulations outline the Commonwealth of Massachusetts'
procedures for regulating solid waste activities.

Corresponding Remedial Action fa)
During remedial design, the use of the CDF for storage of treated
material will address these requirements.

***************

7. Authority - FRR

Requirement
TSCA - Storage and Disposal (40 CFR 761.60 - 761.79)

Status
Applicable

Requirements
These regulations specify the disposal/destruction requirements
of PCB materials in excess of 50 ppm. Dredged materials with PCB
concentrations greater than 50 ppm may be disposed by alternative
methods which are protective of human health and the environment,
if shown that incineration or disposal in a chemical landfill is
not reasonable or appropriate.

Corresponding Remedial Action(a)
The requirements of this regulation will be attained during
remedial action. A test burn will be conducted to determine
optimum equipment configuration and operating parameters to
achieve the required PCB destruction removal efficiencies.

***************

8. Authority - FRR

Requirement
Clean Water Act (CWA) - 40 CFR, Parts 125, 230, and 307

Status
Applicable
59
-------
Requirement synopsis
These regulations specify that a best management program (BMP) be
developed to minimize release of pollutants from the facility.
These requirements also state that no alternative that-impacts a
wetland shall be allowed if there is a practicable alternative.
If there is no practicable alternative, impacts must be
mitigated. Effluent standards incorporated by reference are
considered for target levels.

Corresponding Remedial Action(s)
A BMP will be developed and will include sedimentation control
around the excavation/dredging area. Since dredging of the Hot
Spot sediments is necessary since it is the sediments themselves
that are contaminated, dredging will be conducted to minimize
impacts to the Estuary and adjacent wetland areas. Dewatering
effluent levels will utilize best available control technology to
reduce contaminant levels prior to discharge.

***************

9. Authority -Federal Criteria, Advisories, and Guidance (FCAG)

Requirement
Federal Ambient Water Quality Criteria (AWQC)

Status
Applicable

Requirement Synopsis

Federal AWQC are health-based criteria that have been developed
for 95 carcinogenic and noncarcinogenic compounds.

Corresponding Remedial Action(s)
AWQC are incorporated into Massachusetts DEP surface water
quality standards. Levels for effluent generated by dewatering
will reflect current guidance.

***************

10. Authority - SRR

Requirement
DEP - Massachusetts Surface Water Quality Standards (310 CMR
4.00) and Wastewater Treatment (310 CMR 12.00)

Status
Applicable

Requirement Synopsis
DEP Surface Water Quality Standards incorporate the federal AWQC
as standards for the state surface water.

60
-------
Corresponding Remedial Action (3)
Dredging will be implemented to minimize sediment resuspension
and subsequent PCB mobility. Effluent from the dewatering of the
sediments will also use these standards as target levels and will
utilize best available control technology.

***************

11. Authority - FRR

Requirement
Clean Air Act (CAA) - National Ambient Air Quality Standards
(NAAQS) (40 CFR Part 40)

Status
Relevant and Appropriate

Requirement Synopsis
These standards were primarily developed to regulate stationary
stack and automobile emissions.

Corresponding Remedial Action (3)
Incinerator emissions will be controlled by Best Available
Control Technology such that the regulations are met. In
addition, fugitive dust in the work area will be controlled by
water sprays or other dust suppressants, as required.

*************** - -

12. Authority - SRR

Requirement
DEP - Air Quality and Air Pollution Control (310 CMR 6.00 - 8.00)

Status
Relevant and Appropriate

Requirement Synopsis
These standards were primarily developed to regulate stationary
stack and automobile emissions.

Cog responding Remedial Action Is)
Incinerator emissions will be controlled by best available
control technology so that the regulations are met. In addition,
fugitive dust in the work areas will be controlled by water
sprays or other dust suppressants, as required.
***************
61
-------
13. Authority - Federal Executive Order

Requirement^
Wetlands Executive Order (EO 11990)

Status
Applicable

Requirement Synopsis
Under this regulation, federal agencies are required to minimize
the destruction, loss, or degradation of wetlands, and beneficial
values of wetlands.

Corresponding Remedial Action(si
Dredging in the wetland is required to remove the Hot Spot
contamination. However, dredging of Hot Spot sediment will
attempt to minimize impacts to the extent practicable.

***************

14. Authority - Federal Executive Orders

Requirement
Floodplains Executive Order (EO 11988)

Status
Applicable

Requirement Synopsis
Federal agencies are required to reduce the risk of flood loss,
to minimize impact of floods, and to restore and preserve the
natural and beneficial value of floodplains.

Corresponding Remedial Action(a)
Dredging of sediment from the Hot Spot is expected to have
minimal impact on the floodplain of the Acushnet River.

***************

15. Authority - SRR

Requirement
DEP - Wetlands Protection (310 CMR 10.00) and
Certification for Dredge and Fill (314 CMR 9.00)

status
Applicable
62
-------
Requirement Synopsis
These regulations are promulgated under Wetlands Protection Laws,
which regulate dredging, filling, altering, or polluting inland
wetlands. Work within 100 feet of a wetland is regulated under
this requirement. The requirement also defines wetlands based on
vegetation type and requires that effects on wetlands be
mitigated.

Corresponding Remedial Action(s)
Dredging in the wetland is required to remove the Hot Spot
contamination since it is the sediments themselves that are
contaminated. However, dredging of Hot Spot sediment will
attempt to minimize impacts to the extent practicable.

***************

16. Authority - SRR

Requirement
Coastal Zone Management (301 CMR 20.00)

Requirement Synopsis
Under these regulations, agencies are required to minimize the
destruction, loss, or degradation of wetlands, and beneficial
values of wetland.

Corresponding Remedial Actions
Dredging is required to remove the Hot Spot contamination.
However, dredging of Hot Spot sediments will utilize various
control options and will attempt to minimize impacts to the
extent practicable.

****************

17. Authority - FRR

Requirement
OSHA - General Industry Standards (29 CFR Part 1910)

Status
Applicable

Requirement Synopsis
These regulations specify the 8-hour, time-weighted average
concentrations for various organic compounds. Training
requirements for workers at hazardous waste operations are
specified in 29 CFR 1910.120.
63
-------
Corresponding Remedial Action(s)
Proper respiratory equipment will be worn, if necessary, if it is
impossible to maintain the work atmosphere below the allowable
concentrations. Workers performing remedial activities will be
required to have completed specified training requirements. Air
monitoring will be conducted during remedial activities.

***************

18. Authority - FRR

Requirement
OSHA - Safety and Health Standards for Federal Service Contracts
(29 CFR 1926)

Status
Applicable

Requirement Synopsis
This document contains instructions concerning worker safety at
RCRA or Superfund hazardous waste facilities.

Corresponding Remedial Action(si
All appropriate safety equipment will be maintained on-site, and
appropriate safety procedures will be followed during
remediation.

***************

19. Authority - FRR

Requirement
OSHA - Recordkeeping, Reporting, and Related Regulations (29 CFR
1904)

Status
Applicable

Requirement Synopsis
This regulation outlines OSHA recordkeeping and reporting
regulations for an employer.

Corresponding Remedial Action(si
This regulation is applicable to the remedial action
contractor(s) operating the facility, and compliance with this
requirement will be included in the contract.

***************
64
-------
20. Authority - SRR

Requirement
DEP - Hazardous Substance Right-to-Know (310 CMR 33) ;
DPH - Hazardous Substance Right-to Know (105 CMR 670)

Status
Applicable

Requirement Synopsis
These regulations outline the informational requirements for
hazardous substances that may affect workers associated with the
Department of Environmental Protection or the Department of
Public Health.

Corresponding Remedial Action(s)
The requirements of these regulations will be attained during
alternative implementation.

**************
65
-------
{/-
Daniel 5. Creenbaum
Commissioner
of Waste
-------
Mr. Julie Belaga
U.S. EPA
March 20, 1990
Page 2
disposal site which would be consistent with a future permanent
or temporary solution for the entire disposal site. M.G.L.
Chapter 2IE allows the implementation of remedies on portions of
a disposal site. Once the remedial actions are developed for the
remainder of this disposal site, the Department will evaluate the
reduction of total site risk, in conformance with the MCP.

You should be aware that the EPA's current project manager, Mary
Sanderson, and past project manager, Frank Ciavattieri, should be
commended for a superb job in managing this complex project.
Their efforts to include the State in the Superfund process at
this site have been greatly appreciated.

The Department looks forward to working with you in implementing
the preferred alternative. If you have any questions, please
contact Helen Waldorf at 292-5819.
Very truly y
Smmissioner
Department of Environmental Protection
DSG/BWSC/pc
-------
RESPONSIVENESS SUMMARY

NEW BEDFORD HARBOR SUPERFUND SITE

HOT SPOT OPERABLE UNIT

NEW BEDFORD, MASSACHUSETTS
APRIL 1990
U.S. ENVIRONMENTAL PROTECTION AGENCY

REGION I
-------
The U.S. Environmental Protection Agency and the
REM III Team assembled this Responsiveness Summary
with assistance from the U.S. Army Corps, of Engineers
and the Massachusetts Department of Public Health.
Their assistance is greatly appreciated.
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NEW BEDFORD HARBOR SUPERFUND SITE
HOT SPOT STUDY AREA
RESPONSIVENESS SUMMARY

TABLE OF CONTENTS

Page

PREFACE 1

I. OVERVIEW OF REMEDIAL ALTERNATIVES CONSIDERED IN THE
FEASIBILITY STUDY, INCLUDING THE SELECTED REMEDY .... 3

II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS .... 4

III. SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT
PERIOD AND EPA RESPONSES 9

A. Citizen Comments 14

B. Commonwealth of Massachusetts' Comments 33

C. Potentially Responsible Party Comments 38

1. Rationale for Hot Spot as an Operable Unit

2. -Reliability/Validity of Data
2.1 USAGE Analytical Data
2.1.1 Test Protocols
2.1.2 Analytical Methodology
2.2 Combining Data Across Studies
2.3 Contouring Method
2.4 Data Not Included in HSFS
2.4.1 Baseline Environmental Risk
Assessment
2.4.2 Sediment Quality Data - 1987 Hot
Spot Survey
2.4.3 Air Quality Data
2.4.4 Toxicity Data
2.4.5 CDF Stability Data
2.4.6 Pilot Dredging Operational Data
2.4.7 Results Meeting Decision Criteria

3. Risk Assessment/Toxicity of PCBs
3.1 Additional Contaminants of Concern
3.2 Exposure Assumptions
3.2.1 Methodology
3.2.2 Direct Contact Route of Exposure
3.2.3 Incidental Ingestion
3.2.4 Ingestion of Lobster Tomalley
3.2.5 Consumption of Seafood
3.2.6 Uncertainty Analysis
3.2.7 Airborne Route of Exposure
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3.2.8 Dermal Absorption of PCBs
3.2.9 General Comments on Exposure
Parameters
3.3 Toxicity of PCBs
3.3.1 PCB Epidemiological Studies
3.3.2 Differences in Potency Among
Different PCB Mixtures
3.3.3 Initiation versus Promotion
3.4 Risk Evaluation
3.5 Greater New Bedford Health Effects Study
3.6 Ecological Risk
3.6.1 Environmental Risk Assessment
3.6.2 Benthic Survey

4. Fate and Transport
4.1 Migration of PCBs from Hot Spot
4.2 Combined Sewer Overflow (CSO) Locations
4.3 Atmospheric Transport

5. Biodegradation of PCBs
5.1 Natural Biodegradation as an Alternative to
Remedial Action
5.2 Biodegradation as a Treatment Technology

6. Minimal Action Alternative/Minimal Action Risk
6.1 No Action Alternative
6.2 No Action Risk

7. Evaluation of Remedial Alternatives for 'Hot Spot
7.1 Screening/Evaluation of Alternatives
7.2 Evaluation of Capping for the Hot Spot

8. Pilot Study/Dredging
8.1 Pilot Objectives
8.2 Scale up of Pilot Study Results to Hot Spot
8.3 Potential Release of Non-Aqueous Phase
Liquids
8.4 Changes in Estuary Hydraulics Due to Dredging
8.5 Volatilization of PCBs during Dredging &
Disposal
8.6 Pilot Study Toxicity Testing
8.7 Sediment Resuspension during Pilot Study
8.8 Turbidity Monitoring during Pilot Study
8.9 Dredge Production
8.10 Potential Problem Situations during Dredging
8.11 Potential Environmental Impacts during Pilot
Study
8.12 PRP Access to Pilot Study Site
8.13 Confined Disposal Facility
8.14 PCB Removal
8.15 Dredging and Operations
8.16 Other Contaminants

ii
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8.17 Cost Estimates
8.18 Equipment Availability
8.19 Confined Aquatic Disposal (CAD)

9. Unit Processes
9.1 System Input Rate
9.1.1 Sediment Flow Into CDF
9.1.2 Estimate of Solids
9.1.3 Solids from Pilot Study
9.2 Sediment Dewatering
9.3 Incineration
9.3.1 Feasibility
9.3.2 Scrubber Water Discharge
9.3.3 Air Pollution Control
9.3.4 Solidification of Ash
9.4 Costs Estimates

10. Evaluation of Alternative Treatment Technologies
10.1 Alternative Technologies
10.2 Solvent Extraction
10.2.1 Toxicity of TEA
10.2.2 Pilot Testing of New Process
Hardware
ATTACHMENT A - COMMUNITY RELATIONS ACTIVITIES CONDUCTED
AT THE NEW BEDFORD HARBOR SUPERFUND SITE

ATTACHMENT B - PUBLIC HEARING TRANSCRIPTS:
AUGUST 16, 1989 INFORMAL PUBLIC HEARING
AUGUST 22, 1989 PROPOSAL BY AVX CORPORATION
SEPTEMBER 25, 1989 INFORMAL PUBLIC HEARING TO
CLARIFY PROPOSAL(S)
ill
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Preface

The U. S. Environmental Protection Agency (EPA) held a 74-day
public comment period from August 4, 1989 to October 16, 1989 to
provide an opportunity for interested parties to comment on the
draft Feasibility Study (FS) and the July 1989 Proposed Plan
prepared for the New Bedford Harbor Superfund Site/Hot Spot Study
Area in New Bedford, Massachusetts. The draft FS examines and
evaluates various options, called remedial alternatives, to
address sediment contamination in the Hot Spot Study Area. EPA
identified its preferred alternative for the cleanup of the Study
Area in the Proposed Plan issued on August 3, 1989, before the
start of the public comment period.

To facilitate Site cleanup, EPA has organized its investigation
of the New Bedford Harbor Site into two segments, known as
operable units. A Remedial Investigation (RI) and FS for the
first operable unit, the Hot Spot Study Area, was conducted
between 1988 and 1989. The FS incorporates findings from
previous harbor studies including the 1984 FS of the upper
Estuary,; the 1989 Engineering. FS and Pilot Study; and the 1989
Baseline Public Health Risk Assessment — a study that assesses
the potential risks to public health and the environment
associated with Hot Spot sediment contamination. An FS
addressing overall harbor contamination, the second operable unit
or phase of cleanup, is scheduled for completion in 1990.

The purpose of this Responsiveness Summary is to document EPA
responses to the questions and comments raised during the public
comment period on the Hot Spot Study Area. EPA has carefully
considered all of these questions and comments before selecting a
final remedial alternative to address Hot Spot Study Area
sediment contamination of the New Bedford Harbor Site.

This Responsiveness Summary is organized into the following
sections:

I. Overview of Remedial Alternatives Considered in the
Feasibility Study. Including the Selected Remedy - This
section briefly outlines the remedial alternatives evaluated
for the Hot Spot in the FS and the Proposed Plan, including
EPA's preferred alternative.

II. Background on Community Involvement and Concerns - This
section provides a brief history of community interest and
concerns regarding the New Bedford Harbor Site.

III. Summary of Comments Received Purina the Public Comment
Period and EPA Responses - This section summarizes the oral
and written comments received during the public comment
period and provides EPA responses to them.
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In addition, two..attachments are included in this Responsiveness
Summary. Attachment A provides a list of the community relations
activities that EPA has conducted to date at the New Bedford
Harbor Site. Attachment B contains copies of the transcripts
from the informal public hearings held on August 16 1989
August 22, 1989 and September 25, 1989.
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I. OVERVIEW OF REMEDIAL ALTERNATIVES CONSIDERED IN THE
FEASIBILITY STUDY, TNOLUDING THE SELECTED REMEDY

Using the information gathered during the 1988-89 Hot Spot FS and
Risk Assessment, EPA identified specific objectives for the
cleanup of the New Bedford Harbor Site/Hot Spot Study Area. The
response objectives are:

1. Significantly reduce polychlorinated biphenyl (PCB)
migration from Hot Spot Area sediments to the water
column and sediments throughout the Harbor.

2. Significantly reduce the amount of remaining PCB
contamination that would need to be remediated in order
to achieve overall harbor cleanup.

3. Protect public health by preventing direct contact with
Hot Spot sediments.

4. Protect marine life currently in direct contact with
Hot Spot Study Area sediments. The second operable
unit of the harbor cleanup will include specific target
cleanup goals for contaminants throughout the Harbor.

EPA has developed a cleanup program to address sediment
contamination at the Hot Spot Study Area. The selected remedy
includes: removing contaminated sediments from the Hot Spot
using a cutterhead dredge, dewatering the dredged sediments,
incinerating the sediments in an on-site transportable
incinerator, solidifying the ash residue, if necessary, and
providing interim storage of the treated sediments following the
completion of the remediation process. Ultimate disposition of
the treated material will be addressed in the second operable
unit for the Site.
Other Alternatives Evaluated in the Feasibility Study

In the Hot Spot Study Area FS, EPA screened and evaluated a
number of potential cleanup alternatives for the New Bedford
Harbor Site/Hot Spot Study Area. The FS describes the
alternatives, as well as the screening criteria used by EPA to
narrow the list to four potential remedial alternatives. Each of
these alternatives is described briefly below. The Proposed
Plan, which identifies EPA's preferred alternative for the Hot
Spot Area, also contains brief descriptions of the alternatives
considered in detail in the Hot Spot Study Area FS. A detailed
-description of remedial alternatives can be found in the Hot Spot
Study Area FS and in the Record of Decision Summary. The'Hot
Spot FS is available as part of the Administrative Record for the
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Site, which is available for inspection at the New Bedford Free
Library at 613 Pleasant Street in New Bedford, Massachusetts and
at the EPA Records Center at 90 Canal Street in Boston,
Massachusetts.

Hot Spot Study Area Remedial Alternatives;

1. Minimal No Action: Under this alternative,
institutional measures would be taken to restrict Site
access and caution against swimming, fishing and
shellfishing in the Hot Spot Area. No dredging or
treatment of sediments would occur.

2. Sediment Removal and Incineration: This is EPA's
selected remedy.

3. Sediment Removal and Solidification/Disposal: Hot Spot
sediments would be removed using a cutterhead dredge
and transported by hydraulic pipeline to the Confined
Disposal Facility (CDF) area. Dredged sediments would
be solidified on-site; the solidified material would be
transported to an off-site Federally-approved landfill
for disposal.

4. Sediment Removal and Solvent Extraction: Hot Spot
sediments would be removed using a cutterhead dredge
and transported by hydraulic pipeline to the CDF area.
Dredged sediments would be treated using solvent
extraction, a process that uses a solvent to remove
PCBs from contaminated sediments or soils. The PCB-
enriched solvent extract would be incinerated at an
off-site Federally-approved facility. Solidification
of the remaining waste material would be used to
immobilize metals, as necessary, prior to temporary
storage of the treated sediment.

II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS

The New Bedford Harbor Site is an urban tidal estuary located at
the head of Buzzards Bay in southeastern Massachusetts. The
harbor is bordered by the towns of New Bedford, Acushnet,
Dartmouth and Fairhaven. From the 1940's until the late 1970's,
two electrical capacitor manufacturing facilities in New Bedford
released PCBs onto the adjoining shoreline mudflats of the plants
and into New Bedford Harbor, through discharged wastewaters
containing PCBs and through alleged intentional dumping. Field
studies conducted by EPA and the Commonwealth of Massachusetts
between 1976 and 1982 identified PCBs and heavy metals in
sediments and marine life throughout a 1,000-acre area of the
harbor and upper Buzzards Bay.
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In 1982, the New Bedford Harbor Superfund Site was added to the
National Priorities List,(NPL), making it eligible to receive
federal funds for investigation and cleanup under the Superfund
program.

Community involvement in EPA and state investigations of New
Bedford Harbor has been high throughout the RI/FS process.
Concerns in the bordering communities have initially focused on
potential public health impacts as a result of living near the
harbor or eating fish caught in the harbor, potential impacts on
the local fishing industry, and potential limitations on
waterfront development activities. Community concerns now also
include the environmental, economic and health impacts of
remedial alternatives being evaluated for the Hot Spot portion of
the Site, and ensuring that, following the Hot Spot remediation,
remaining harbor contamination will be addressed.

Community concerns first surfaced in the mid-1970's, following
the discovery of extensive PCB contamination in the harbor (water
column and bottom sediments) and in the tissue of fish caught
both in the harbor and in adjacent Buzzards's Bay. In 1977,
Massachusetts banned construction in the harbor intertidal and
subtidal zones to prevent re-suspension of contaminated
sediments, and the Commonwealth also banned shellfishing or
bottom fishing within the harbor and certain sections of
Buzzard's Bay to protect public health.

These bans resulted in high levels of concern from commercial
fishermen, who feared that the public's association of'New
Bedford Harbor with hazardous wastes would negatively impact the
local fishing industry. Area residents and commercial
enterprises interested in developing commercial space on the
harbor, repairing aging wharves, or undertaking other activities
were equally concerned about the building moratorium. Further
concerns expressed by area residents focused on delays in plans
to improve the Route 6 bridge over the Acushnet River Estuary.

In 1982, the U.S. Coast Guard placed signs, in English and in
Portuguese, notifying the public of the restrictions on fishing
and swimming. These signs were subsequently vandalized.

In 1983, the EPA, the Massachusetts Department of Environmental
Protection (DEP) — formerly known as the Department of
Environmental Quality Engineering (DEQE) — and the Massachusetts
Department of Public Health (DPH) held a public meeting on the
cleanup plan for the Acushnet River Estuary. The DPH
representatives reviewed the results of the preliminary health
study conducted in 1981 to evaluate PCB concentrations in area
workers and residents, and stated that the tests showed elevated
PCB levels in certain area workers and in persons who ate fish
caught in the harbor. DPH stated that a more comprehensive
follow-up study would be conducted by the DPH, the Massachusetts
-------
Health Research Institute (MKRI),. and the U.S. Centers for
Disease Control (CDC). Approxiiiiately 800 to 1,000 residents of
New Bedford, Fairhaven, Acushnet and Dartmouth would be studied
to determine whether they had been exposed to PCBs, the level of
PCB contamination in the bloodstream, and the correlations
between life-style and PCB blood concentrations would be
evaluated.

In 1984, EPA received a petition from Fairhaven residents calling
for preventing public access to the estuary; a ban on dredging in
the Acushnet River; a comprehensive program testing area property
for contamination; meetings with EPA officials; and an area-wide
health study.

In June 1984, EPA distributed 25,000 informational pamphlets on
harbor contamination to schools in New Bedford, Acushnet and
Fairhaven, providing information on ways to prevent exposure to
contaminants in the harbor area. EPA added to its public
information program in July 1984 by placing additional English
and Portuguese warning signs around the harbor.

On July 11, 1984, a public meeting, cosponsored by DPH and the
League of Women Voters was held to announce the commencement of
the DPH, MHRI and CDC health study. The study, which was
released in 1987, showed that few of the residents who had
participated in the study had elevated levels of PCBs, and that
the residents with the highest risk of elevated PCBs (from
occupational exposure or eating harbor fish) had PCB levels
within the typical range of the U.S. population. The health
study also suggested that the Massachusetts regulations banning
fishing in the harbor may have contributed to lowering risks to
the local population. Following the release of the study,
health-related community concerns, which had been very high, were
significantly reduced.

In September 1984, EPA released the results of the "fast-track"
Feasibility Study. Among the options considered in the FS were
dredging of contaminated sediments, channelizing the harbor, and
capping areas on either side of the channel. Public concerns
over these recommendations centered on the possibility of
resuspending contaminated sediments during the dredging
operations, public health impacts, and impacts upon the port's
commercial operations. EPA responded to these concerns,
determining that additional studies of dredging and disposal
techniques should be conducted before proceeding with the harbor
cleanup.

The New Bedford Area Chamber of Commerce released a "PCB White
Paper" in July 1985 to provide the area population with
information on the nature of PCBs, their potential health
effects, the CDC health study, sources of PCB contamination in
-------
the harbor, EPA's investigations, and choices facing New Bedford
area residents regarding EPA's future activities.

On April 30, 1987, EPA held a public information meeting to
describe plans for a proposed pilot project to evaluate dredging
and disposal options in New Bedford Harbor, and to inform the
public on the progress of the Feasibility Study for the Site.
EPA also distributed an English and Portuguese fact sheet on the
Pilot Study to those people on a mailing list that EPA developed
for the Site. Approximately 175 people attended this meeting. A
question and answer period was held during which the public asked
over 50 questions. Questions focused on the physical
characteristics of the Site, possible cleanup options, the Pilot
Study, public involvement, and the schedule for the RI/FS.
Following the conclusion of the EPA meeting, the community group,
People Acting in Community Endeavors (PACE) presented a thirty
minute videotape they had produced about the Site.

In October 1987, EPA released an information update in English
and Portuguese on recently completed plans for the Pilot Study.
In addition, a public meeting was held on October 22 to present
EPA, DEP, and U.S. Army Corps of Engineers' (COE) plans for
construction and operation of the Pilot Study. EPA, DEP and the
COE also conducted a public availability session on October 24 to
answer questions from the community on a less formal basis than
at the public meeting.

Citizen involvement in EPA's decision-making process at the Site
increased significantly with the formation of the Greater New
Bedford Environmental Community Work Group (CWG) in October 1987.
The CWG was formed under the auspices of the Office of the Mayor
of New Bedford. Its formation was supported by EPA, which sought
to ensure that the public be kept informed about the Site and be
able to participate actively in site-related decision making.
The CWG has a membership of approximately 25 people, although a
core group of approximately 10 to 12 members formed after the
group had met a number of times. Members were recruited from
each of the surrounding four communities and include
representatives from environmental, fishing, business and other
interests. From October 1986 through the present, CWG members
have met on a regular basis with EPA and other agencies involved
in the cleanup and study process, such as the U.S. Army Corps of
Engineers.

EPA released an information update in June 1988, again in both
English and Portuguese, to inform the public on EPA's proposed
testing of an innovative treatment technology, under the auspices
of the Superfund Innovative Technology Evaluation (SITE) program,
at the New Bedford Site and to invite public comment on EPA's
proposal. The information update also provided information on
the CWG and on the progress of the Pilot Study. Following the
release of the update, EPA held an open house at the SITE
-------
demonstration. A large number of local and state--~pfficials, CWG
members, and members of the general public attended. Following a
number of presentations on the SITE program to the CWG, the CWG
unanimously endorsed conducting the demonstration.

EPA held a public groundbreaking ceremony on April 7, 1988 to
announce the beginning of construction of the Confined Disposal
Facility (CDF), as a part of the Pilot Study. The ceremony was
well attended and included a representative of the CWG.

Throughout the FS and Pilot Study process, the CWG remained
extremely active in providing EPA with information and
suggestions. To facilitate their involvement, the CWG applied
for and was awarded a $50,000 EPA Technical Assistance Grant
(TAG) in November 1988. The CWG, in turn, contracted with an
independent consulting firm to assist them in providing EPA with
detailed technical comments on the Hot Spot FS and other aspects
of the New Bedford Harbor cleanup.

Public interest in the Pilot Study continued, and EPA held two
days of site visits in December 1988 to allow the public to view
the dredging equipment and Confined Disposal Facility (CDF).

EPA held an informational public meeting on August 3, 1989 on the
Hot Spot FS and the Proposed Plan. The meeting was attended by
approximately 40 people. The principal community concerns
expressed at that time include the following:
>
Impacts of Dredging. Residents expressed concern that
dredging would spread the contamination in the Hot Spot Area
through the Harbor.

On-Site Incineration. Residents expressed interest in the
efficiency of the incinerator and its effect on metals. In
addition, residents requested information on what air
quality monitoring would be conducted in association with
operation of the incinerator.

Residual Metals. Residents expressed concern that the
residual incinerator ash would be considered a hazardous
waste and questioned EPA's on-site disposal of the ash.
Residents were also concerned that the metals could pose a
risk to public health.

An informal public hearing was held on August 16, 1989 to accept
oral comments on EPA's Proposed Plan. A second public meeting
was held on August 22, 1989 to allow the PRPs and opportunity to
present an alternative to EPA's Proposed Plan. Finally, on
September 25, 1989, the CWG sponsored a meeting to provide an
opportunity for its members and members of the public to ask
questions about EPA's Proposed Plan or the PRPs1 proposed
alternative.

8
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III. SUMMARY O? COMMENTS RECEIVED DURING THE PUBLIC COKHLNT
PERIOD AND EPA RESPONSES

This Responsiveness Summary responds to the comments received by
EPA concerning the Hot Spot FS and the Proposed Plan for the Hot
Spot Study Area of the New Bedford Harbor Superfund Site. EPA
received a large number of written comments during the 74-day
public comment period (August 4 - October 16, 1989). A number
of oral comments were presented at the August 16, 1989 informal
public hearing. Copies of the transcripts to all three of the
informal hearings that were held are included as Attachment B.
Copies are also available at the New Bedford Free Library, the
information repository that EPA has established for the Site; and
at the EPA Records Center at 90 Canal Street, Boston,
Massachusetts, 02114 as a part EPA's Administrative Record.

EPA received a total of 54 documents or "comments" during the
public comment period. Due to the large number of documents
received, EPA established a "Document Control Number" (DCN)
system to track and to refer to specific documents. The "Comment
Tracking Sheet" on the following 4 pages lists the DCN, the
source, the author, a general description of the document, and
the date of the document.

A large number of the documents received during the public
comment period from the PRPs are extremely voluminous, and in a
number of cases, are over 50 pages in length. It would be
extremely wasteful and redundant for EPA to reproduce all of the
comments verbatim in this Responsiveness Summary. A number of
the documents make similar comments on the same issues. Thus,
representative excerpts from a number of documents are presented,
including a citation to the document it was taken from via the
corresponding Document Control Number (DCN). These excerpts are
presented in a lightly shaded block ("redline") to distinguish
them from the EPA responses which follow. EPA lifted excerpts
from each document to indicate what EPA believes to be the
substance of the comment. In a number of instances, cross-
references are made to other responses or to the Record of
Decision Summary. All of the documents received during the
public comment period are included in the Administrative Record
for the Site in Section 5.3.

Section A presents the citizen comments that EPA received during
the public comment period, and Section B presents the comments
that EPA received from the Commonwealth of Massachusetts.
Section C contains the PRPs1 comments, which are predominantly
technical in nature. Because of the large volume PRP documents
that addressed similar issues, the comments were divided into ten
categories. These categories are presented in the Table of
Contents to this Responsiveness Summary and they are reiterated
at the beginning of Section C.
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NEW BEDFORD HARBOR HOT SPOT COMMENT TRACKING SHEET

SOURCE AUTHOR DESCRIPTION
DATE
•PRP Comments;

1 Ropes & Gray

2 Ropes & Gray

3 Ropes & Gray

4 Ropes & Gray

5 Ropes & Gray
Galvani

Spaulding

Brown &
Wagner

Hoff &
O'Brien
6 Ropes & Gray Dr. Jaeger
7 Ropes & Gray Whysner
8 Ropes & Gray Whysner
Ropes & Gray
10 Ropes & Gray
11 Ropes & Gray
12 Ropes & Gray
13 Ropes & Gray

14 Nutt, Mclen
& Fish

15 Nutt, Mclen
& Fish

16 Nutt, Mclen
& Fish
Rose

Harris,
et al.

Terra

Balsam

Balsam
Review of Draft Hot Spot FS 10/16/89

Review of Draft Hot Spot FS 07/28/89

Review of Draft Hot Spot FS 08/30/89

PCB Dechlor. & Detox, in the
Acushnet Estuary (Inc. Appen. A)

Critique: Draft Hot Spot FS 05/89
Critique: Draft Public Health 10/12/89
Evaluation

Recent Findings RE: T/PCBs 10/11/89
Implications for NBH Risk
Assessment

Draft Final Baseline Public 10/11/89
Health Risk Assessment NBH FS
(Including Appendix E)

Affididavits of Daniel Granz, 10/89
Raymond Castio, Raymond Cabral,
and Gary Haskins

Deposition of David A. Kennedy; 05/26/86
Cambra

Aquatic Toxicity & Bioacummula- 10/89
tion Potential in Marine Env.

Review of Draft Hot Spot FS 10/13/89
New Bedford Harbor Evaluation

Comments on NBH Hot Spot FS & 10/16/89
Proposed. Plan

Remedial Action Program NBH 10/16/89
Mass Estimates of PCBs in Upper 07/27/89
Estuary Sediment, NBH (Att.A)
10
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DCN SOURCE
AUTHOR
DESCRIPTION
DATE
17 Nutt, Helen Balsam
& Fish - -
IS Nutt, Mclen Balsam
& Fish
19
20
21
22
23
24
25
26
27
28
29
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
& Fish
Nutt, Mclen
Balsam
Balsam
Balsam
Balsam
Balsam
Balsam
Terra
Terra
Terra
Terra
Balsam
& Fish
Theoretical Evaluation-Effect- 10/09/89
iveness of Capping PCB Contam-
inated NBH Bed Sediment, Draft
(Att.B)

Recolonization Dynamics and 03/15/89
Bioturbation Process in Marine
Sediments; Relationship to
Proposed Capping of NBH (Att.C)

NBH Thin Layer Sediment Samp- 08/11/89
ling Program (Att.D)

Hydraulic Study of the Acushnet 08/31/89
River Watershed, NBH (Att.E)

Tidal Cycle Flux Measurement
Data (Att.F)

Extreme Velocities in the Upper 09/20/89
Acushnet River Estimated By
Inlet-Basin Model (Att.G)

Extreme Velocities in the Upper 09/20/89
Acushnet River Estimated by
the Dambrfc Model (Att.H)

Assessment of PCBs in Acusnet 10/10/89
River Upper Estuary Wetlands
Sediments (Att.I)

Toxicant Profile for Poly- 11/88
chlorinated Biphenyls (PCBs)
(Att.J)

Hazard Evaluation for New 10/89
Bedford Harbor (Att.K)

New Bedford Exposure Assess- 10/89
ment (Att.L)

New Bedford Harbor Risk 10/89
Assessment (Att.M)

Use of Simple Box Model to
Estimate PCB Water Column Con-
centrations Before and After
Capping in the Upper Estuary,
Draft (Att.N)
11
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DCN SOURCE
AUTHOR
DESCRIPTION
DATE
, Mclen Balsam
Fish
31 Joint Defend- Rizzo
ants

32 Joint Defend- Rizzo
ants

33 Joint Defend- Rizzo
ants

34 Joint Defend- Rizzo
ants

35 Joint Defend- Rizzo
ants
36 Joint Defend- Rizzo
ants

37 Joint Defend- Rizzo
ants
38 Joint Defend- Rizzo
ants
39 Joint Defend- Rizzo
ants
40 Joint Defend- Rizzo
ants
41 Joint Defend- Rizzo
ants
PCB Biotransfonnation in 10/16/89
Aquatic Sed.: NBH & Other
Sites (2 Vol) (Att.p)

Comments on Draft Final Hot 10/16/89
Spot FS

Aerial Photo of Pilot Study
(ref. on p. 5-27 of DCN #31)

List of Principal Issues pre '85
(NUS internal memo)

Proposed Pilot Study Meeting 11/13/89
Minutes (EPA memo)

Hot Spot Feasibility Study, 09/08/89
NBH; Revised Review of Pilot
Dredging Report

Proposed NBH Pilot Dredging
Project

Comments on the Final Draft 06/30/88
Detailed Analysis of Remedial
Technologies for the NBH
Feasibility Study

Aerovox Comments on the Draft 02/22/88
"lexicological Profile for
Selected PCBs (Aroclor -1260,
-1254, -1248, -1242, -1232,
-1221 & -1016)"

AVX Comments on ATSDR's Draft 02/22/88
Profile: "Toxicological Profile
for Selected PCBs (Aroclor
-1260, -1254, -1248, -1242,
-1232, -1221 & 1016)

Memo to Mr. Richard J. Hughto 10/02/89
from Robert J. Rossi Regarding
NBH PCB Monitoring Data

Memo Concerning Trip to NBH 10/12/89
and Acushnet River Estuary
(10/6/89) (Terra Representa-
tives James and Nye)
12
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DCN SOURCE
AUTHOR
DESCRIPTION
DATE
42 Joint Defend- Rizzo
ants
Summary of the Deposition of
Bernard Gregory Cambra
05/28/89
43 Joint Defend- Rizzo
ants

44 Joint Defend- Rizzo
ants

45 Joint Defend- Rizzo
ants

46 Joint Defend- Rizzo
ants

Massachusetts Comments;

47 Massachussets Craffey
Citizen Comments;
48
49
50
51
52
53
Commun . Work
Group
Commun . Work
Group
Citizen
Citizen
Citizen
Citizen
Chadwick
Environ
Handke
Pereri
Hughes
Davis
Summary of the Deposition of
David A. Kennedy

Affidavit of Raymond Castino
Affidavit of Gary Haskins
Affidavit of Raymond Cabral
54
Citizen
Sylvia
ARARs & Comments on the Hot
Spot Operable Unit & Hot Spot
FS
Comments on Proposed Plan &
Capping Alternatives

Comments on "Baseline Public
Health Risk Assessment"

Comments on Clean Up Plan for
PCB "Hot Spot" Area in New
Bedford

Letter in Support of Inciner-
ation of PCBs in the Hot Spot

Comments on EPA Alternative
for the Hot Spot

Comments on EPA Alternative
for the Upper Estuary of the
Acushnet River

Comments on EPA's Preferred
Alternative
05/28/89

05/28/89

05/58/89

05/28/89
10/16/89
10/13/89

09/22/89

10/16/89

08/11/89

10/09/89

10/16/89

8/30/89
13
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li. CITIZEN COKJ...&UT3

The "citizen" comments that were received, along with EPA
responses, are taken from the following documents:

DCN # Author

48 Greater New Bedford Harbor CWG

49 Greater New Bedford Harbor CWG

50 Handke

51 Pereri

52 Hughes

53 Davis

54 Sylvia

SOURCE: DCN #48; GREATER MEW BEDFORD ENVIRONMENTAL COMMUNITY
WORK GROUP

COMMENTS ON: (1) EPA Proposed Plan for Operable Unit 1,
New Bedford Harbor Super fund Site ,

(2) PRP alternative plan of capping for the upper
Estuary

DREDGING AND INCINERATION

Six Work Group members support the EPA proposal of dredging and
incineration as the remedial alternative for the Hot Spot.
we support the EPA**: proposal to dredge the Hot: Spot
incinerate, th^. contaminated sediments. We feel this remedy
offers an &|^.|cient and permanent solution to the cleanup of the
Hot Spot, :;«||p: ;is '' tAe most highly PCB-contaminated area In the
entire Sup^Sp^ • Site, - We also feel that 'capping is a feasible
technologY;i|ipR;t
-------
During all periods of dredging, water quality must be
monitored by use of an appropriate indicator species and/or
chemical analysis, with sampling to be done in locations
that extend to the New Bedford Hurricane Barrier.
' quality the cleanup
should b« monitored to detect possible PCB volatilization
during dredging operations, as well as possible PCB
byproducts or metals volatilization produced during
incineration*!
f f fff. *ft+e •. ftffff&f+tsftfsr .VAVVV.4
Th¥ PCB concentration in effluent water~produced during
sediment dewatering should be subject to the same discharge
requirements as those applied; to local industries*
- EPA has^^ n arrangement* to deal
with the strong possibility that incinerator ash will
contain hazardous levels of metals. Considering their
to temporarily dispose of the incinerator ash on-site, in
the unl ined ; CDF , th i s is a disturbing omission »;

The immobilization of metals by solidification of incinerator ash
is a new technology without a proven track record. A second
point: how "temporary1* will temporary disposal be?

EPA RESPONSE TO COMMUNITY WORKGROUP/DREDGING AND INCINERATION
t

I. The EPA believes that the selected Hot Spot remedy offers a
permanent solution for the Hot Spot contamination, as is set
forth in this Record of Decision. Further, the statutory
preference for treatment, particularly for the highly
contaminated sediment of the Hot Spot that continues to act
as a source of contamination to the remainder of the Site,
is satisfied by this interim action.

2. The EPA believes that capping is a feasible technology for
less contaminated areas of the Site. As discussed in
Section IX. A of the Record of Decision Summary and Section 7
of this Responsiveness Summary, EPA is currently evaluating
capping as an alternative for the Estuary, excluding the Hot
Spot, and has retained capping as a viable alternative for
portions of the Lower Harbor and Bay. These sections also
provide the basis for the elimination of capping for the Hot
Spot on the basis of long-term maintenance concerns, as well
as the conspicuous lack of permanent and significant
reduction in the mobility, toxicity or volume of the Hot
Spot contaminants.

3. The results from the Pilot Dredging Study conducted by the
Corps of Engineers (COE) , in conjunction with the

15
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Engineering Feasibility Study and other reference materials,
'^.will be uctifi to guide the reaedial design process. Many of
the details for actually implementing the dredging and
incineration of the Hot Spot sediments will be developed
during this design phase.

During the pilot study, resuspension of sediment was also
minimized with no plume of resuspended material moving away
from the dredging area, and no measured elevated levels of
contaminants were detected in the water column outside the
immediate vicinity of the dredging operation. The
cutterhead dredge has been selected for use at the Site
based on its ability to minimize resuspension, as well as
several additional operational advantages. These advantages
are discussed in detail in the Pilot Study Report (New
Bedford Harbor Superfund Pilot Study: Evaluation of Dredging
and Dredged Materials Disposal; Interim Report, June 1989).
Additional concerns relating to dredging are addressed in
Section 8 of this Responsiveness Summary.

There are several considerations for the timing of the
dredging activities. A major concern is that there is
adequate water depth for the dredge to operate in. The
Pilot Study was conducted in a cove where the depth of the
water ranged from 0.0 to 0.5 feet at mean low water, similar
to the depths found in the Hot Spot Area.

The monitoring program thart will be conducted during the
dredging will provide the major basis for the dredging
operation. However, the feasibility of dredging only during
the incoming tide will be examined during the design prfase.

4. Water quality will be monitored during dredging in a manner
similar to that conducted during the pilot study dredging.
During the Pilot Study, EPA conducted monitoring at the
Hurricane Barrier, and no adverse impacts to water quality
were detected. Therefore, EPA does not believe that
monitoring down to the Hurricane Barrier is necessary.

During the pilot study, monitoring was conducted at the
Coggeshall Street bridge, and no contaminants were found to
be migrating beyond this point. Since the Hot Spot
sediments to be dredged are further north in the Estuary
than the pilot study location, EPA believes that monitoring
to the Coggeshall Street bridge only is adequate. The
design phase will examine the number, location, and type of
monitoring stations to be maintained during the dredging
operation.

5. Air monitoring will be conducted throughout the period of
remediation. Air monitoring will be conducted in the
vicinity of the dredging operation, as well as a part of the

16
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incineration operation to ensure that the incinerator meets
all applicable starve rds, particularly for air emissions.

6. The effluent produced as a result of sediment dewatering is
subject to ARARs specific to this action, including federal
and state requirements under the Clean Water Act and the
Surface Water Quality Standards (310 CMR 4.00),
respectively. The effluent will be treated to reduce PCBs
and heavy metals using best available control technology
prior to discharge back into the Harbor.

7. The EPA has considered the possibility that the incinerator
ash may contain high levels of metals. As discussed in
Section X.A of the Record of Decision Summary, a leaching
test will be performed on the ash to determine if it
exhibits the characteristic of toxicity and is, therefore,
considered a hazardous waste under the Resource Conservation
and Recovery Act (RCRA) . If the leaching test reveals that
the ash is a RCRA hazardous waste, the ash will be
solidified such that metals no longer leach from the ash at
concentrations that exceed the standards set forth for
determining the toxicity of a material. The Hot Spot
Feasibility Study considered the additional (unit) cost of
stabilization of the incinerated sediment in the overall
cost estimate for the incineration alternative.

EPA does not consider immobilization of metals by
solidification to be a new technology. Solidification by a
variety of techniques has been talcing place for years.
Innovative uses of solidification are being examined under
EPA's SITE program, but these applications examine
immobilization on "untreated" sediment rather than on
incinerated ash.

Refer to Section 9.3.4 of this Responsiveness Summary for
• further information regarding the solidification process.

UPPER ESTUARY CAPPING

Three Work Group members support the capping alternative for the
upper
General SI
Being a community work group, we feel we must decidCwbat i* best
for the community. , He can understand other group meatoerff
preference for dredging,and incineration of Hot Spot'iedlment«f
and would agree with.them providing that in the Second Operable
Unit, capping is the alternative chosen. However, we fee\ there
is a possibility that capping may not even be offered as an

17
-------
alternative to deal with contaminated sediments in the' remaining
Superfund Site.,

Therefore ;' we "have "to" take ' the" worst' ' case" scenario;;'.' just::;as?EPS
did on the Public Health Risk Assessment: The Cleanup of the
Upper Estuary, harbor and lower harbor could cost as ouch a $900
million. At this price tag/ we feel Aerovox and Cornell-Dubilier
would be out of business, resulting in the loss of more than
1,000 jobs in the Greater New Bedford area*
~ S t s -• AV SS, f fS f

We feel that capping, the alternative offered by the PRPs through
Rizzo Associates, is a complete alternative and we give our
support to this plan*
to all the alternatives and
"would; :::;;not>- i:haye; ieven considered the capping alternative
$15- million price tag
for dredging; and incineration. Also, treatment of
dewater ing effluent may be a serious problem.

EPA should have given bi ©degradation a closer examination *
* There are doubts concerning PCB incineration as
technology has -the potential to contribute to air pollution,
as well as the fact that the American public isn't ready to
endorse this technology. Lack of public support may cause
delay.

GENERAL: GROUP STATEMENT
of EPA's work plan for
the chosen alternative. This work plan should be made
available: ^ ;-tb ^••:;:Us^'and:,"our'i'technical advisor in time to permit
thorough exam^ati^
We insisC^tSafi^f allure in any part of the ' remecliar' project
as it apjpliea to the Hot Spot, resulting in an increase of
PCBs i|^.tn'e air or water f is grounds for EPA to cease and
desist"; this project until the problem is clearly identified
and corrected.
•***
EPA RESPONSE TO COMMUNITY WORKGROUP/UPPER ESTUARY CAPPING
EPA has considered capping for the Hot Spot sediment/ as
well as for the remainder of the Harbor. As discussed in
Section IX.A of the Record of Decision Summary and Section 7

18
-------
of this Responsiveness Summary, capping was eliminated for
further consideration for the Hot Spot and was maintained
for the remainder of the Site. EPA eliminated the capping
alternative due to the uncertainty of the long-term
effectiveness of the cap for the Hot Spot sediment, as well
as concerns over implementability. EPA was concerned about
the inability of the cap to provide a permanent barrier to
migration of highly contaminated sediment. EPA is currently
evaluating capping as an alternative for the Estuary,
excluding the Hot Spot, and has retained capping as a viable
alternative for portions of the Lower Harbor and Bay.

The one statement that "EPA has seriously underestimated the
$15 million price tag for dredging and incineration" lacks
detail or supporting information. EPA is unaware of the
specific concerns being raised. Moreover, the supporting
cost estimates for each of the alternatives that underwent
detailed analysis are included in Section 7 of the Hot Spot
FS. As indicated in the EPA publication, "Guidance for
Conducting Remedial Investigations and Feasibility Studies
Under CERCLA," the level of accuracy of cost estimates is
+50 percent/-30 percent. While the actual costs for on-
site incineration are difficult to estimate precisely, the
$374 per ton estimate used in the FS is within the range
provided by guidance, vendor quotes, and actual incineration
bids from other sites. Refer to Section 9.4 of this
Responsiveness Summary for a more complete discussion of the
cost estimates.
s

EPA does not consider treatment of the effluent generated by
the dewatering process to be a "serious problem." Various
types of water treatment have been conducted in a multitude
of industrial and municipal settings for decades, with
discharge permits issued nationwide.

EPA has examined the requirements for treating this effluent
prior to discharge back into the Harbor, and EPA believes
that existing technologies are capable of treating the
effluent to acceptable levels. The design process will
examine best available control technology and various
treatment options (e.g., coagulants) to achieve the
discharge goals.

Refer to Section 9 of this Responsiveness Summary for a more
complete discussion of the treatment processes for the Hot
Spot sediment.

EPA has examined biodegradation in the Feasibility Study
process. Refer to Section 5.0 of this Responsiveness
Summary for a detailed discussion of the biodegradation,
both as an alternative "remedial action" and as treatment
technology examined by EPA.

19
-------
The EPA recognizes that biotransformation of PCBs in New
Bedford Harbor sediment appears to be occurring. However,
studies conducted to date do not provide sufficient data for
a reliable estimation of in-situ biochemical decay rates or
half-lives, as well as the toxicity of the decay products.
This information is crucial to evaluate the length of time
that would be required for removal of PCBs from the Hot Spot
sediment by natural processes. Research suggests that the
half-life of anaerobic degradation of heavily chlorinated
PCBs may range from 7 to 50 years (Brown and Wagner, 1986).
Based on this half-life estimate and assuming first order
decay, the time required for biodegradation to reduce a
sediment PCB concentration of 4,000 ppm (the lower limit of
the Hot Spot) to 50 ppm is approximately 50 to 300 years.
The EPA finds this time frame for remediation unacceptable,
especially when there are other remedial alternatives
currently available for implementation.

Given the quantity and high level of PCB contamination in
the Hot Spot sediment, the EPA believes the Hot Spot will
remain a source of contamination, and that contaminants will
continue to migrate throughout the entire Site if not
addressed. Although the EPA recognizes that PCBs undergo
transformation processes to varying degrees in the
environment, no scientific data has been provided to the EPA
to date which documents that the levels of contamination in
the Hot Spot would be reduced to levels that the EPA
believes would no longer present a risk to human health or
the environment within a reasonable timeframe.

5. Incineration has been used at several hazardous sites
nationwide. Refer to Section 9.3.1 of this Responsiveness
Summary for a listing of the sites where incineration has
been Used.

The fundamental concept of incineration is the utilization
of extremely high temperatures to volatilize and destroy
organic compounds. An afterburner on the incineration unit
is used to destroy the volatilized contaminants. The
treated material is then tested to ensure that the material
no longer has the characteristics of a hazardous waste.

The PCB disposal requirements promulgated under TSCA are
relevant and appropriate for the hot spot sediments. Under
TSCA, soils contaminated with PCBs at concentrations greater
than 50 ppm may be disposed of in an incinerator or a
chemical waste landfill. Since the hot spot sediments are
heavily contaminated (greater than 4,000 ppm), incineration
is an appropriate technology to remediate the Hot Spot under
TSCA.
20
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Refer to Section 9.3 of this Responsiveness Summary for a
more complete discussion of incineration technology

6. The public will be kept informed as the remedial design
process proceeds. The COE will be conducting the design of
the Hot Spot remedy, with the assistance of an engineering
design firm. Remedial designs generally proceed with the
development of a 30%, 60%, 90% and 100% plans and
specifications design package. The COE has an exhaustive
procedure whereby "bidability" and "constructability"
reviews are conducted by a team of people with expertise in
various fields (e.g., water treatment, incineration), once
the design is complete, the project goes out to bid, and the
contract is awarded to the lowest "responsible11 and
"responsive" bidder. In all, the design phase is estimated
to take approximately one year to complete.

As the plans and specs are developed, EPA will seek public
input. However, the actual plan and spec packages are
confidential to protect the integrity of the bidding
process. EPA is aware of the public interest in the design
process and the interest in reviewing material, and EPA will
work with the Community Workgroup to establish a mechanism
to provide for review, without compromising the integrity of
the bidding process.

7. One portion of the design process will examine "decision
criteria* in a manner similar to that used during the Pilot
Study. Limits will be established for the dredging
operation. If the monitoring indicates that these allowable
levels are being exceeded due to dredging, the dredging
operation will be discontinued until the problem is
identified and corrected.

EPA will establish similar limits for the operation of the
incinerator. EPA will establish an air monitoring program
to ensure compliance with the emissions requirements. If
emissions limits are exceeded, the equipment will be shut
down and the operating parameters will be adjusted to meet
the emissions requirements. Further, the incinerator will
be equipped with automated controls which will be able to
monitor a wide variety of operating parameters. The
transportable incinerator will have automatic shut-down
capability in the event that emissions limits are being
exceeded.

Refer to Section 8.0 of this Responsiveness Summary for a
more complete discussion of the dredging operation and its
controls, and to Section 9.0 for the operation of the
incinerator.
21
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SOURCE: DCN 149; GREATER NEW BEDFORD ENVIRONMENTAL COMMUNITY
WORK GROUP

COMMENTS ON: "Draft Final Baseline Public Health Risk
Assessment New Bedford Harbor Feasibility Study,
August 1989"

Overall Assessment

The "Draft Final Baseline Public Health Risk Assessment; New
Bedford Harbor, Feasibility Study, August 1989" (Ebasco 1989)
(hereinafter referred to as the "Draft Report1*) is a
comprehensive examination of potential'risks to public health
under baseline conditions 'from exposure to PCBs, lead, copper,
and cadmium detected in the sediment, surface water biota, and
air within the New Bedford Harbor site. The risk was
quantitatively estimated from potential exposure to the four
contaminants through dermal contact and ingestion of sediments,
^d::f ingest iorv:.;.of-.:fish^-;:::':Tn.;additlon/y a quantitative assessment of
risk from potential inhalation of airborne contaminants was
performed; :;::oniy ;::;fbr; PCBs due to limited air data. A qualitative
assessment of risk was performed for dermal contact and ingestion
of'-water '* """ '"""" -•'•"•••"•••'-

The'vassessmehtr:'Is'"av"reasohable- examination of the potential
current risks to human health under the various exposure
assumptions presented within the Draft Report. The report
evaluated the appropriate exposure pathways for the appropriate
populations of concern. The estimates of risk are conservative,
but the assumptions used are within the range of those used in
assessments of other sites and acce^ted^J^rjgSEPA.

However?"ENVIROH":beHeves::::'there-:::are some technical flaws and
questionable assumptions used in the Draft Report. Even though
these flaws and assumptions do not individually affect the risk
estimates appreciably, they should be evaluated prior to using
the results presented in the Draft Report as the basis to
determine the need for and the extent of remediation at the New
Bedford Harbor site._ The following summarizes the major areas of
concern:.

Inhalation of airborne contaminants is considered a
principal pathway of exposure. This conclusion was based on
an initial screening of -pathways based oh exposure to PCBs*
However, inhalation of airborne contaminants was found to
contribute only 0.025 percent of total doser while Ingestion
of aquatic biota, direct contact with sediments and '"'
ingestion of sediments contribute greater than 99 percent of
the total, dose (Table 2-2, pg. 2-15). Xt is therefore not
evident why this pathway which contributed such a small
percentage of total exposure was considered important.

22
-------
Various exposure assumptions (e.g., sediment ingest ion
rates, gastrointestinal factors for metals) are the upper
end of the range of estimated values and thus provide the
opportunity for an overestimate of risk. It would be more
appropriate to estimate risks for both a "typical case" (or
average) and "reasonable worst-case1* using separate exposure
assumptions in each as proposed in USEPA's recently
published Exposure Factors Handbook (USZPA 1989a) (e.g., for
sediment Ingestion rates an average value of 200 mg/day is
recommended by EPA) , In addition, sensitivity analyse*
should be performed on the exposure assumptions to determine
the effect of the degree of uncertainty associated with the
estimated risks,

The toxicity profile for PCBs (Appendix Df pgs» 0-1 through
D-36) has various discrepancies and flaws.* These are
detailed in an attachment to this memo. However, the flaws
do hot effect the risk estimates presented in the
Reportif " """"'v"": "" ..... '""" ' " """ ......... ...............

The toxicity prof ile for cadmium includes discussion of ah
increased risk of cancer of the prostate in workers exposed
to cadmium via inhalation (Appendix D, pg. D-39) , That
conclusion has been refuted (Doll 1985} and the profile
should center on the increased risk of lung cancer. This
will not however change the cancer potency factor usedf in
the- riaJt estimations* ...........
4
the toxicity profile for lead is incomplete (Appehdiit 0f
pgs. D-47+). Recent neurologic and behavior studies in
infants and young children should be included* Xn\ addition,
there ia ho EPA' accepted AIC for lead Table 3-1, pg. 3-4)
(USEPA 1988). Work currently in progress in EPA'* Office of
Air Quality Planning and Standards (OAQPS) supports the use
of a biokine tic/uptake model to estimate blood lead levels
in children from exposure to specific environmental lead
levels (USEPA 1989b) . This approach should be developed in
this document « The, USEPA IRIS ( EPA 's on-line database)
report for lead states the Agency's RfB (reference dose,
formerly known as acceptable daily intake or ADI) Group
considered it "inappropriate to develop an RfD for inorganic
PA I969C) ^ — ........
EPA RESPONSE TO COMMUNITY WORK GROUP/PUBLIC HEALTH RISK
ASSESSMENT

EPA believes that the assessment was performed in accordance
with current EPA guidance and is a reasonable examination of
the potential current risks to human health under the
various exposure assumptions, evaluating the appropriate

23
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exposure pathways for the populations of concern. Some of
the risk estimates in the Public Health Risk Assessment
report are conservative, but the assumptions used are within
the range of those used in assessments of other sites and in
accordance with EPA guidance.

However, the minor technical flaws in the Public Health
evaluation do not affect the risk estimates for the hot
spot. The comments presented here will be evaluated prior
to using the results as the basis to determine the need for
and the extent of remediation for the second operable unit
at the New Bedford Harbor Site.

In addition to direct contact and incidental ingestion of
Hot Spot sediments, EPA examined risks from the ingestion of
biota. Table 1 from the Record of Decision Summary presents
the biota concentrations used for the risk calculation.
Additionally, Table 2 presents a specific hot spot
concentration from an area of probable exposure for the
direct contact risk estimate. As can be seen from Table 2
the hot spot concentration of 9923 ppra presents a
carcinogenic risk of 7 x 10"5, which is outside of the EPA
target risk range.
SOURCE: DCN #50; HANDKE
COMMENTS ON: Draft Final Baseline Public Health Risk
Assessment; New Bedford Harbor Feasibility Study,
August 1989.
shortened (13
pages is too long) and should emphasize facts and
conclusions, not structure of the report and methodology,*
2rt Tables 2-7 and 2-14 list no references for the exposure
""""'"'assumptions given. "" """"""'

3. .., Given the emphasis on seafood consumption as a route of
exposure 'in thl'e" risk assessment, it is essential that the
magnitttd£ of the'uncertainty regarding the amount of seafodd
addressed*« »
4. The tafcles in Appendix C which compute a body dose for
noncarciriogens use a nonconservative assumption by
calculating a tine-weighted average. This is not consistent
with EPA policy. (It is my understanding that instructions
regarding this issue will be included in the Revised
superfurid Public Health Evaluation Manual.) The tables in
Appendix C calculate an average daily body dose and then
compare it to a standard for lifetime daily exposure. The

24
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exposure scenario, for example, is for a child being exposed
20 days/year. Calculating an average daily body dose
ignores the fact that on 345 days the child receives a dose
of zero and on 20 days receives a dose 15 times greater than
the dose calculated in the table. Risk should be evaluated
for the actual dose received, not for a time-weighted
average dose» "'

5. *,. The tens "toxlcokinetic factor* is too broad.,. A more
appropriate and accurate term would be "relative absorption
factor.* — —•

Pp'. B-3 through B-5i:":''::'Tjie''devel6pm^
gastrointestinal absorption factor for Norback and Weltman
(1985) study clearly describes the absorption percenta for
all six studies considered as "minimum." A discussion
should be included which makes clear whether or not the use
of minimum absorption percents is a conservative assumption
which is protective of public health.:

6. ... The Bibliography heeds to be proofread.**

EPA RESPONSE TO HXNDKE

The substantive comments presented are addressed in Section
3.0 of this Responsiveness Summary. The remaining comments
speak to stylistic issues, which EPA will not formally
respond to here since they do not impact the technical
quality of the report and conclusions reached.

SOURCE: DCN f51; PERERZ

COMMENTS ON: INCINERATION OF PCBs

I, being a staunch supporter of a clean environment, am in
complete accord with the Environmental Protection Agency on
the proposed incineration of the polychlorinated biphenyls
from the hot spots in the Acushnet River Estuary, and the
incineration taking place at shoreline facilities as
theUnited States Environmental Protection
For 'thWI^whom are critical and in opposition to this plan,
I would fcindly urge them to bring forth documents that would
give credence to, their expertise or basic knowledge in the
environmental field where hazardous or toxic waste is
concernedr either-organis-or-inorganic.
25
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EPA RESPONSE TO PERERI

The remedial action selected for the Hot Spot is consistent
with the - requirements of the Superfund program. The
selected remedy is protective of human health and the
environment for the Hot Spot area. Any short term concerns
associated with dredging or incineration can be controlled
with existing, available technologies. The remedy also
satisfies the statutory preference for the use of treatment
as a principal element.

To support the EPA's selected remedy, the EPA has developed
an extensive Administrative Record for this site. This
record includes a variety of remedial investigations and
feasibility studies to address harbor contamination. In
addition, a large number of reference documents and
technical articles are included to support the EPA's remedy
selection process.

SOURCE: HUGHES; DCN #52

COMMENTS ON: PREFERRED ALTERNATIVE

Flrst> r wiauld like to > applaud EPA for taking the first
concrete : steps to remedy ? this site. f/; For: too many years this
site has languished as more and more studies were conducted.
The time for action is long overdue. Also, X would: like to
commend £.C» Jordan for the high caliber of the recently
issued Feasibility Study,;

I am, however, somewhat puzzled by EPA's rationale for
selecting the "preferred alternative." I would like to
review below the alternative selection process, as X see it.
Four alternatives were considered in detail;

1. No Action
2 . Incineration
3* Solidification/Disposal
4 . Extraction
action" alternative does not merit ' serious
discnis|tion as a remedial measure. The solidification/
disposlfeoptio'n does not result in destruction of the PCfls
and therefore' cannot be considered "permanent1* » Nor is this
option cheap ($13 million) . Therefore, it should be
eliminated. On that we agree.

Now we are left to choose between incineration and
extraction. Both involve dredging, storage and dewa^ering
of the sediments. Both result in nearly complete
destruction of the PCBs, However , extraction offers a

26
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significant cost advantage (about $2 million) . Actually,
the cost advantage is probably even greater, since:

1. EPA 'a incineration costs are relatively low.
2. Coats for fixation (about $500,000) are included in the
edit estimate for extraction, even though the
extraction residue is not likely to require fixation*

In addition to its cost advantage, I 'must also point out
that extraction has several environmental benefits. ;
Extraction produces a separation of organic contaminants
(PCBs) and inorganic contaminants (heavy metals) . In this
manner, the method of treating each fraction can be fully
optimized without sacrificing treatment effectiveness.
Extracted oils are destroyed in a liquid incinerator, while
metals reside with the solids. Leaching tests (EP Toxicity)
conducted on the extracted solids indicate that the heavy
metals ;do not leach to » any great extent,

In contrast, the incineration of Hot Spot sediments will
likely result in undesirable emissions, especially heavy
metals. Incineration also tends to oxidize and thereby
"liberate" metals in the residual ash, making them more
prone to leach into the environment. Therefore, while both
technologies reduce the volume, toxicity and mobility of thi
PCBs, the extraction process also reduces the mobility of
the metals* Incineration, on the other hand, increased the
mobility, and possibly the toxicity, o£ the,, metals v"'
r;e, Jordan; &rthe public meeting held b« Atigttifc "37
raised .reliability as a .potential drawback of extraction.
The extraction process developed by Resources Conservation
Company has been demonstrated in one full-scale application
and in several pilot tests, while it has probably not
received as much scrutiny as incineration, it is certainly
not an unknown technology,

In light of the above, I suggest that EPA reconsider its
decision to incinerate the sediments, and employ extraction
instead* Keep In mind that EPA is supposed to encourage the
use 6|^|h1ioVa'tivir ^and alternative technologies. TMTlfthr
Bedf orJuHarbor Rot Spot Operable Unit presents a perfect
..to 40; 3ust that .

EPA RESPONSE TO HUQHE8

The "No Action" or minimal action alternative is routinely
evaluated in a feasibility study to provide a benchmark for
comparison for other remedial alternatives. EPA agrees that
the "No Action" alternative does not merit serious
consideration for the highly contaminated Hot Spot
sediments. With regard to solidification, no destruction of

. 27
-------
the PCBs would occur, and the volume of the contaminated
material would'be increased. The solidification alternative
assumes the availability of an off-site disposal facility.

The cost estimates developed by EPA in the feasibility study
are within the +50% to -30% accuracy level common to
feasibility study estimates. However, EPA believes the
overall effectiveness and reliability of incineration, as
opposed to solvent extraction, for Hot Spot sediments
justifies the slightly greater cost. It is not known how
many "washes" with solvent extraction are necessary in order
to obtain the degree of PCB destruction assured by
incineration of the Hot Spot sediment.

EPA acknowledges the viability of solvent extraction for
treatment of contaminated sediment. In fact, EPA has
selected solvent extraction for remediation at other
Superfund sites. However, the levels of contamination for
which this technology has been selected are far below those
existing at the Hot Spot. Solvent extraction is undergoing
detailed analysis for the second operable unit FS where the
levels of contamination are distinctly lower than those
found in the Hot Spot.

SOURCE: DCN 153; DAVIS

COMMENTS ON: EPA PROPOSED PLAN FOR HOT SPOT

In order to evaluate the EPA proposal it would seem the
matter should be put in the context, of the whole harbor*.»«
A remediation judgement of the upper estuary should be done
with some anticipation of a resolution for the rest of the
harbor.

Unlike the balance of the inner harbor, the upper estuary is
an ecosystemi with a long term status such to require a
resolution consistent with and supportive of the status*
The standard of remediation would thus seem to differ from
the rest of the inner harbor..,*

While\.1khe" segments of the river differ, the surface area of
the I^w0ir estuary is much larger, by approximately an order
of magnitude. PCB transport occurs from the surface area of
the underlying sediments. Since it is a primary source of
depositions into the outer harbor, it is the ingestion of
edible fish in the outer harbor that are consequential to
health effects*;

No one has calculated the relative influences of the .high
level but remote & localized PCBs (Hot Spot Area), vs the low
level but distributed PCBs immediately facing the outer

28
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harbor. Whatever the judgement, each is influential.
Levels of PCBs in sediments relative to marine uptake is
relative..«

The fear of the author is that the rationale to clean up the
hop spot area (over 90% of the PCBs) signaled a question on
the part of the Agency to the rest of the harbor. The
alternative was expressed without giving any indication of a
plan for the balance of the harbor.»*
* / t ff * r f ff fff f r r f vf •.-.••

It would seem that if damages to the natural resources are
an issue, then restoration of the resources is an equal:
issue. And there should be no limit in the means of
redress, if the means are proportioned to the causes of the
decline. Without prioritizing specific causes, it is near
unanimous that access to the inland spawning grounds by
anadromous species is a major cause of the decline.

There are.a variety of points the author would like to make.
One of which is the role of the locality in matters of this
sort. It would seem to me that participation ia desirable.
But it would seem that unless some authority is given to the
local level, participation will be limited.,.» As much as
the current local administration has moved in favor of
environmental considerations, it has resulted in only one
fulltime person for the task....:

In the event of the execution of the EPA alternative, there
is no need to incinerate the PCBs* Based on the affinity of
PCBs to sediments, and their low-water solubility, the PCBs
would be relatively encased. With a liner, the containments
would be assured. And'this would exclude the possible
mobilization of the heavy metals« Gidley, an authority on
this topic, advocates same. The incineration cost is
approximately $5 million, and thus the savings would be
approximately one third. The only drawback would be the
volume reduction lost, through incineration. But this is
small (circa 10%), and also excludes any need to remove ash
depositions.

It would'seem, given the large area to be dredged for the
lower estuary, for the area of the upper estuary outside the
hot spog^rea,. that'any dredging alternative is prohibitive
(froaji^tq 3'feet PCBS taper off-to negligible levels: at
3 feeffline whole inner harbor contains circa 400,000 cubic
yards)*' Consequently, the only solution for the balance of
the harbor is capping..,.

Indeed the EPA is justified in their concern to remove the
high levels in the hot spot areas. It would seen, with the
exclusion of incineration, that the cost can be used to
integrate both methodologies, such that the total cost may

29
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be marginally different. The:author has not had time to
even begin a cursory comparison, but it would seem that with
large scale apparatus in place, with means used to
enter/exit the estuary, that a cap could be put ..-In .."place
concurrent with the hot spot removal...

A last point mentioned in my oral testimony, is to test foil
the presence of PCDFs in marine biota; in view of their
presence in the sediments* Further, some specific testing
of marine species should be tested for the upper estuary, in
particular shellfish and crustaceans, so a time series can
be established.. This should be easy to do by means of
cages,

Attachments are enclosed in support of the above. The
document;::"historical Profile: Buzzards Bay" by the author,!;
is; still;•;"in-"draft form though essentially complete.. It is
hoped;: the;.;:f inal copy can; be. submitted and'::included.

EPA RESPONSE TO DAVIS

1. EPA recognizes the different portions of the harbor,
and segmented the Site for study accordingly: the Hot
Spot, the Estuary, and the Lower Harbor and Bay. These
geographical areas are shown on Figures 1 and 2 of the
Record of Decision summary.

2. As a part of the Superfund process, EPA evaluates the
risks posed by the contaminants present at a 'site.
Exposure scenarios are developed to reflect the
characteristic uses and location for specific site.
The risk assessment conducted for the Hot Spot followed
EPA guidance for conducting such assessments. Refer to
section 3.0 of this responsiveness summary for a more
complete discussion of site risks.

3. Numerous studies and reports on the harbor present the
nature and extent of the PCB contamination and the fate
and transport of this contamination in the environment.
Sediment data shows that approximately 48% of all the
PCBs within the Estuary are located in the Hot Spot.
The results of several monitoring programs demonstrate
that approximately 2 pounds of PCBs migrate out of the
upper Estuary daily. These PCBs are ultimately
transported to portions of the Lower Harbor and
Buzzards Bay, where they are redeposited, volatilized
into the atmosphere, or taken up into the food chain by
aquatic Biota.

4. This Hot Spot operable unit is the first of two
operable units planned for the New Bedford Harbor site.
Operable units are discrete actions that comprise

30
-------
incremental steps toward a fin*\ remedy. They may be
actions that completely address :•. geographical portion
of a site or a specific site problem. This Hot Spot
remedy addresses both this geographical portion of the
site and the specific contamination found in this area.
This Hpt Spot interim action is consistent with future
actions being considered by EPA because this remedy
calls for the removal of approximately 48% of the total
PCB mass from the Estuary portion of the site, which
acts as a continuing source of contamination to the
remainder of the site. Refer to Section 1.0 of this
responsiveness summary for further discussion of
rationale for the Hot Spot as an operable unit.

5. The main vehicle for community involvement has been the
greater New Bedford community workgroup (CWG). The CWG
has received a $50,000 Technical Assistance Grant from
EPA to provide additional resources for review and
comment of EPA activities conducted at the site. The
CWG holds regular meetings, in addition to public
meetings sponsored by EPA and the State, to keep the
local community informed about site activities.

6. EPA is currently evaluating capping as an alternative
for the Estuary, excluding the Hot Spot, and has
retained capping as a viable alternative for portions
for the lower harbor and bay.
»
7. EPA has conducted analysis of sediment for dioxin and
PCDFs. Because the results were either extremely low
or below detection limits, EPA believes that PCDF
analysis of biota is not warranted.

8. A number of other issues alluded to in the comments
here are addressed throughout the Record of Decision
summary and sections of this Responsiveness Summary.
The Attachments the author references are included in
the Administrative Record.

SOURCE: DCH 154; SYLVIA

COMMENTS ON: PREFERRED ALTERNATIVE

Sylvia, resident of New Bedford at the foot of
i« along the Acushnet River, am very concerned
about putting dikes in because I feel that any control of
the water flow will sake the Acushnet River one big mud flat
from Wood Street bridge to Coggeshall street Bridge*
therefore the smell of the mud will be so great that we
won't be able to stand it in this neighborhood.
31
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I feel that the whole project of capping ths PCBs in the
upper estuary will be controlled by the dike;: only, without
the dikes I do not believe that the capping would last. So
I am against diking or capping it in its present areas. I
do think that if Riverside Avenue was continued across the
cove ta;£oggeshall street, it would make a good barrier for
anything in the cove. Therefore, I do think that if the
PCBs were pimped or dredged from the upper estuary to the
cove near Coffin Avenue and Riverside playground where the
depth'from street level to the mud flat of the cove would be
somewhere in the area of 12 ft. or better. There would be
sufficient room to pump all the sediments into it then
proceed vith' the capping and covering it with fill or stone
dust. It would save a few; million dollars plus we could
live with it!
or heated up they
have a tendency to cause cancer. Being so close to where
you want; to burn itf we*re afraid: the particles that come
out of the stacks^; we will bev breatojytvjythem. I think they
should be.: buried in: the ;coveJ
of Coffin Avenue
where the pipes go up Coffin Avenue to Belleville Avenue and
there is complete flooding along Belleville Avenue because
the pipes can't take the pressure. I suggest that the pipes
that run from the pumping station be .diverted straight
acroj^jiiye^ of the cove
and on d^wn alpng^ t^ I also think that the
pipeline that floods Wamsutta Street and Acushnet Avenue
should be diverted ^^^t^ along the waterfront and
in these areas*
EPA RESPONSE TO SYLVIA

1. EPA does not believe that capping the highly
contaminated Hot Spot sediment is an appropriate remedy
because of the levels of contamination that would
remain in the Harbor. Refer to Section IX. A of the
Record of Decision Summary and Section 7 of this
Responsiveness Summary for further discussion. The
concerns about capping expressed in this comment are
being considered in the Feasibility Study currently
underway for the remainder of the Site. The issues of
long term effectiveness and controls required to
maintain a cap will specifically be discussed in this
second feasibility study for the site.

2. Incineration of PCBs is a proven technology for
addressing the type of contamination found in the Hot
Spot. The extremely high temperatures virtually assure

32
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complete destruction of. the organic contamination. Any
materials not destroyed by the incineration process
(e.g., metals) will be controlled through air emissions
control devices. Refer to Section 9.0 of this
Responsiveness Summary for a more complete discussion
of the incineration process.

While the EPA is aware of the flooding problems in the
vicinity of Belleville Avenue, EPA's jurisdiction under
the New Bedford Harbor Superfund Site does not extend
to this area. This issue needs to be addressed by the
City of New Bedford.
B. COMMONWEALTH 07 MASSACHUSETTS COMMENTS
SOURCE: DCN 147; MASSACHUSETTS* DEPARTMENT OF ENVIRONMENTAL
PROTECTION

The Department of Environmental Protection has been requested to
identify Applicable or Relevant and Appropriate Requirements
(ARARs) for the hot spot operable unit of the New Bedford Harbor
superfund site... This request established the close of the
public comment period as the practical deadline for a timely
Agency response to the state's identification of ARARs for this
operable unit. Normally the DEP does not specifically submit, an
"ARARS letter*1 for each site, prior to the signing of a Record of
Decision. The identification of action, location, and chemical
specific ARARs is done at every step in the process of remedial
assessment selection and implementation for a federal superfund
site. We are persuaded, however, that the Hew Bedford Rarbior
operable unit presents a number of unique characteristics which
warrant a focused effort on our part to identify state law*,
regulations, and policies which we feel are applicable or
relevant and appropriate to the Proposed Plan for the Hot Spot*

The Hot Spot remedial action proposed by the agency consists of
removal by dredging, of approximately 10,000 cubic yards of
sediments containing FCBs at concentrations greater than 4,000
ppm which are located in the hot spot area of the Acushnet^River
Estuary. Dredged sediments would be transported by a hydraulic
pipeline to|$i|shoreltne basin known as the confined disposal
facility (CJ3f|||off of sawyer Street in New Bedford, Sediments
would be mped to settle, be dewatered by plate and frame
units, and then incinerated. Incinerator ash would be solidified
and stored in a portion of the CDF, until a decision on its final
disposal is made later,in the project; This operable unit also
includes the necessary air quality control and water treatment
units*
33
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In"" viewing ':thls"'?prd£6sed':'"plan.' the'':t5iepartment": has' 'reviewed
statutes, regulations, and policies in all three of its Bureaus:
Waste- Site Cleanup, Resource Protection, and Waste Prevention.
In addition we have included the concerns of the EOEA offices of
Coastal Zone- Jianagement and Massachusetts Environmental Policy
Act in enforcing' applicable provisions of their standards.
Attached tcTthls letter in Attachment 3 is a short list of the
laws, regulations and policies which comprise the ARARs
identified to date which could apply to the operable unit*
Because of specific concerns, we have concentrated on the
identification of some specific "requirements, and we have
summarized these requirements below, *w
f t f f f fftf f.ft-'ff'-'ffffj.f't.**' f f f "> VSJ*

I." ~ Ehvironmentar
The Massachusetts "Environmental Policy Act (MEPA) establishes
standards to minimize environmental impact on publicly funded
projects.. We believe these requirements are applicable to the
proposed plan. In addition Federal consistency in the coastal
zone requires adherence to applicable standards for the
protection of the environment. - For the proposed plan, the
Department, believes the use of silt curtains around the area to
be dredged. would be an applicable requirement. The; Department
believes that justification for non-use of silt curtains would be
required to be technically well founded, by a monitoring program
near the dredge, such that water quality impacts are minimized
and a level of environmental protection is achieved acceptable to
a decision "making committee. , Monitoring and decision making, on'
dredging operations should achieve a level of control Similar to
that in the pilot study* This level of control would be relevant
to the proposed remedial action to protect coastal resources.
•. S\ S .-*• V. •,•,** f •. Sf*> f*f « .V.<. AV. \ J- \\ V. AS tf*f*f,V AS S XV. V A S S * . -X- VA ^ •> A'A-,SV.% \4.SVMVS .SSW, ,VA .V^/ ^ % ff>*f*
Water pollution cohtfbl during sediment dewaterihg and treatment
must meet best available technology as the applicable
requirement* .Wetlands regulations are applicable to,this
remedial action; where it impacts estuarine areas, as well as
inland vegetated wetlands. They are also applicable to
alterations and;structures located below existing or historical
mean high water, whichever is farther landward.

2. . PtOC^S*', Cdfijfcrol "Requirements
•V.S v^v*wXvX*Xv, ^s^-.%vJv»\Ao«v«X-.v t * .• -. s

Hazardous"'f^||r':Regulations, while exempt from applicability to
control oel^r^ .under MGL chapter 2 IE per se, contain relevant
and appropi||||Sjrequirements. Specifically, side vail and bottom
material li^the^'CpF must achieve a maximum permeability standard
of -IXia- /<»/«««yx the- CDF/must "be covered while it contains hot
spot material,and all residue hot spot material must be removed
from the CDF following the remedial action, Under the provisions
of relevant and appropriate sections of 3iO OCR '30.000, residual
materials from the incinerator must be tested to determine'if
they are a hazardous waste. Appropriate tests are the

34
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Toxicity and TCLP as described in 310 CMR 30.155. If the ash
fails one of these tests, it must be solidified or otherwise
treated so that the material is no longer a hazardous waste as
defined in these regulations*

Solidified ash, if it is to be ultimately discarded and not used
for any structural building purpose, must be stored and
ultimately disposed of as a solid waste. Applicable standards
for storage and disposal of solid wast* are contained in sections
19.11 and 19.111 of the solid waste regulations. For storage of
solidified ash, as a solid waste, all existing and nev landfills
incorporate environmental control systems into the overall
design of the facility to provide protection to oroundwater.
surf ace water and air quality. Por disposal of the solidified
ash, applicable requirements ,of solid waste regulations require a
line material to achieve a 1x10 cm/ sec maximum 'permeability
standard. If the ultimate disposal of solidified ash is a
section of the CDF, the material on the floor and sidewalls must
be demonstrated to meet this applicable standard. The operation
of the incinerator and air quality control equipment must achieve
air quality control standards contained in 310 CMR 6 ^ 00-8
Although the air quality at the site currently exceeds
recommended allowable ambient limits (AALs) for PCBs and lead,
the effect of remedial actions on AALs must be evaluated by
appropriate monitoring and modeling techniques. Remedial
actions, including incinerator operation, must be implemented
..... ,,,,^,.,.,,-,,,,,,.
EPA RESPONSE TO MASSACHUSETTS DEPARTMENT Of ENVIRONMENTAL
PROTECTION

1'. The fact that EPA requested identification of State ARARs
for the Hot Spot Operable Unit is not unusual. On the
contrary, the State must identify ARARs to the lead agency
in a timely manner throughout the remedial investigation and
feasibility study process.

Due to the limited scope of this interim action, standards
or levels of control associated with final cleanup levels
will not be achieved. This action will comply with those
ARARs specific to this interim action. For example,
compliance with RCRA facility and incinerator regulations
will be achieved. Chemical-specific ARARs associated with
final cleanup levels (e.g., Water Quality Criteria and Food
and Drug Administration PCB tolerance level) are not
specific to this action and are outside its scope. ARARs
such as these will be addressed by subsequent actions at the
New Bedford Harbor Site.
35
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A more complete discussion of the ARARs specific to this
interim remedy is included in Section XI.B and in Table 6 of
the Record of Decision Summary.

2. ARARs specific to this interim action will address the major
components of the remedy.

The dredging process will seek to minimize impacts
during operation. Various control options will be
examined in detail during the design phase, such as the
use of monitoring and/or physical barriers (e.g.,
floating booms, silt curtains). The results of the
Pilot Study conducted by the Corps of Engineers will be
utilized during the design process to formulate control
options for the dredging process to minimize and
control sediment resuspension.

Dewatering of the sediments will be conducted to
increase the efficiency of the incinerator. Effluent
resulting from this dewatering process will be treated
using best available technology to reduce contaminant
levels prior to discharge back into the harbor.

The incinerator will be required to operate in
accordance with the TSCA requirements, the RCRA
requirements, and the State Hazardous Waste Management
Regulations.
t
Incineration of contaminated sediment will produce a
residual ash. Following incineration, the Toxicity
Characteristic Leaching Procedure (TCLP) will be
performed on the ash to determine if it exhibits the
characteristic of toxicity and is, therefore, a
hazardous waste, thereby necessitating solidification.
This treated ash will be temporarily stored in an area
adjacent to the confined disposal facility. Ultimate
disposition of this material will be addressed in the
second operable for the site.

3. EPA will examine the use of the Confined Disposal Facility
(CDF) in the dewatering process during design to meet the
State hazardous and solid waste requirements (e.g.,
permeability standards).

4. A brief discussion on the use of silt curtain is provided
below, based on information obtained from the pilot study.

A silt curtain or turbidity barrier is a flexible,
impervious barrier that hangs down vertically from the water
surface. The silt curtain consists of four major elements:
a skirt that forms the barrier, flotation material at the
top, ballast weight at the bottom, and a tension cable. The

36
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flotation and ballast keep the curtain in a vertical
position while the tension cable absorbs stress imposed by
currents and other hydrodynamic forces. The fabric material
is commonly nylon-reinforced polyvinyl chloride (pvc). The
curtains are manufactured in 100-foot long sections that are
joined together for the overall curtain length. The curtain
may be attached to shore or held stationary with large
anchors attached to mooring floats on the ends and smaller
anchors at regular intervals along the length of the
curtain. The primary purpose of the silt curtain is to
reduce turbidity in the water column outside the curtain,
not to retain the fluid mud or bulk of the suspended solids.
The presence of a silt curtain results in a change of flow
patterns in the vicinity of the curtain so that exiting
flows are redirected. Under quiescent condition (currents
less than 0.5 knots (0.85 ft/sec) with no strong tidal
action), turbidity levels outside a properly deployed and
maintained silt curtain can be reduced by 80 to 90 percent
of the levels inside. The curtain used for the pilot study
was to have the skirt anchored to the bottom, with flotation
material at the top to allow for adjustments necessitated by
the rise and fall of the tide. An oil boom was used along
with the silt curtain to contain the thin layer of floating
oil or contaminant that appears on the water surface during
such operations.

The silt curtains deployed during pilot study dredging
sustained substantial damage as a result of severe weather
conditions on November 20, 1989. Rather than delay the
start of dredging operations, the curtain was allowed to
remain in a damaged, and therefore ineffectual, condition
for the greater part of the dredging phase. As the
suspended solids data (Appendix 1 of the Interim Pilot Study
Report) indicates, the levels generated at the point of
dredging dropped rapidly down to background levels. Based
on visual observation and the suspended solids data, the
only phase in which the curtain may have contributed to
reducing turbidity would have been during the Confined
Aquatic Disposal (CAD), or subaqueous capping operation. As
a result of these observations, the curtain was re-deployed
during the placement of cap material in the CAD. Aligned in
a crescent shape formation to the east and south-east of the
CAD cell and located approximately 200 feet from the point
of discharge, it was visually apparent that the curtain
aided in reducing the turbidity levels. In all probability,
however, these levels would have declined prior to reaching
the Coggeshall Street Bridge. What was also readily
apparent was that the initial deployment, periodic movement
and final removal of the curtain resulted in some of the
highest levels of sediment resuspension visually observed
during the project.
37
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While the use of a silt curtain was^-not particularly
successful during the pilot study, ~%he use of silt curtains
will be re-examined in detail during the design process.

C. POTENTIALLY RESPONSIBLE PARTY COMMENTS

As explained previously, the PRP comments were organized into the
10 categories listed below.

CATEGORIES OF PRP COMMENTS

1. Rationale for Hot Spot as an Operable Unit

2. Reliability/Validity of Data
2.1 USAGE Analytical Data
2.1.1 Test Protocols
2.1.2 Analytical Methodology
2.2 Combining Data Across Studies
2.3 Contouring Method
2.4 Data Not Included in HSFS
2.4.1 Baseline Environmental Risk Assessment
2.4.2 Sediment Quality Data - 1987 Hot Spot Survey
2.4.3 Air Quality Data
2.4.4 Toxicity Data
2.4.5 Confined Disposal Facility (CDF) Stability
Data
2.4.6 Pilot Dredging Operational Data
2.4.7 Results Meeting Decision Criteria

3.0 Risk Assessment/Toxicity of PCBs
3.1 Additional Contaminants of Concern
3.2 Exposure Assumptions
3.2.1 Methodology
3.2.2 Direct Contact Route of Exposure
3.2.3 Incidental Ingestion
3.2.4 Ingestion of Lobster Tomalley
3.2.5 Consumption of Seafood
3.2.6 Uncertainty Analysis
3.2.7 Airborne Route of Exposure
3.2.8 Dermal Absorption of PCBs
3.2.9 General Comments on Exposure Parameters
3.3 Toxicity of PCBs
3.3.1 PCB Epidemiological Studies
3.3.2 Differences in Potency Among Different PCB
Mixtures
3.3.3 Initiation versus Promotion
3.4 Risk Evaluation
3.5 Greater New Bedford Health Effects Study
3.6 Ecological Risk
3.6.1 Environmental Risk Assessment
3.6.2 Benthic Survey

38
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4. Fate and Transport
4.1 Migration of PCBs from Hot Spot
4.2 Combined Sewer Overflow (CSO) Locations
4.3 Atmospheric Transport

5. Biodegradation of PCBs
5.1 Natural Biodegradation as an Alternative to Remedial
Action
5.2 Biodegradation as a Treatment Technology

6. No Action Alternative/No Action Risk
6.1 No Action Alternative
6.2 No Action Risk

7. Evaluation of Remedial Alternatives for Hot Spot
7.1 Screening/Evaluation of Alternatives
7.2 Evaluation of Capping for the Hot Spot

8. Pilot Study/Dredging
8.1 Pilot Objectives
8.2 Scale up of Pilot Study Results to Hot Spot
8.3 Potential Release of Non-Aqueous Phase Liquids
8.4 Changes in Estuary Hydraulics Due to Dredging
8.5 Volatilization of PCBs during Dredging & Disposal
8.6 Pilot Study Toxicity Testing
8.7 Sediment Resuspension during Pilot Study
8.8 Turbidity Monitoring during Pilot Study
8.9 Dredge Production
8.10 Potential Problem Situations during Dredging
8.11 Potential Environmental Impacts during Pilot Study
8.12 PRP Access to Pilot Study Site
8.13 Confined Disposal Facility
8.14 PCB Removal
8.15 Dredging and Operations
8.16 Other Contaminants
8.17 Cost Estimates
8.18 Equipment Availability
8.19 Confined Aquatic Disposal (CAD)

39
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10. Evaluation of Alternative Treatment Technologies
10.1 Alternative Technologies
10.2 Solvent Extraction
10.2.1 Toxicity of TEA
10.2.2 Pilot Testing of New Process Hardware
40
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SECTION 1.0 - R^TTONALE FOR HOT ?POT AS AN OPERABLE TTOTT

DCN #1, Page 4, Paragraph 3

... It Is stated that the implementation of remedial action
for the hot spot operable unit must be cost-effective and
consistent with the overall remedial action selected for the
New Bedford Harbor site. But there is no basis in the record
to conclude that the proposed remedial action (other than
the no action alternative) for the hot spot would be cost
effective or consistent with the overall remedial action for
the site; Indeed, consistency with the overall remedial
action for the site cannot possibly be determined prior to
the selection of the remedy. In fact, it is clear, that by
designating the hot spot as ah operable unit and proceeding
to treat it as an interim remedy the Agency is simply trying
to avoid dealing with the site as whole and also seeks to
avoid compliance with the law, including CERCLA, SARA, the
NCP and ARARs, "as well as the restriction to $2 million on
emergency removal measures. The Agency simply has resorted
to a ruse to make up for its own deficiencies* Moreover/'
given the government 'a determination of the amount of.
natural resource damages submitted in the District Court
action, it would appear that any remedial action involving
costs which approach or exceed that amount is not legally of
economically justifiable.

OCN 12, Page 2, Comment 2

The definition of the hot spot area is totally arbitrary.
Contrary to .what is stated in the report (p. 2-5} the parget
level is not; necessarily a "common sense1* level nor^i'si it an
optimization of sediment remediation volume and PCS 'mass
'''''' ' ' ' ........ •••-•• •••- •••• •- -
DCN #2, Page 7, Comment 3

The use of the, word "common sense" to justify the 1PCB target
level is amazing* « It implies that there is some universally
accepted standard for selection of the target » f This is, not
the case ^What|is even more disturbing is that no ^analysis
-, j -4MK Jk S*V k V £fr- .-.-.•.-'•• •• ^ .- We f Wf *• *M jVe*f •fWvf& -.^vwv v ^*< «.
is prodded to
-------
There is no precedent Coi the use of 4000 ppm target
cleanup level for other superfund sites.;
EPA must undertake a scientifically and legally valid
"" definition of .the hot1 spot:| ••••-..,,,.. ,, ,. . ....

EPA RESPONSE

The Hot Spot Area is an area of approximately 5-acres along the
western bank of the Acushnet River Estuary adjacent to the
Aerovox facility. It is noteworthy because of the extremely high
levels of PCBs that have been detected in the sediment. Levels
of PCBs in the Hot Spot sediments range from 4,000 ppm to over
200,000 ppm. Dermal contact and incidental ingestion of this
sediment pose a potential risk to public health. In addition,
potential routes of exposure for marine organisms include direct
contact with the sediment, contact with contaminants in the water
column, and ingestion of contaminated food. Finally, the Hot
Spot continues to act as a source of contamination throughout the
entire Site. This Hot Spot Operable Unit is designed to respond
to these significant threats.

This interim action is protective of human health and the
environment because it provides for the removal and treatment of
the highly contaminated sediments in the Hot Spot. Subsequent
actions will be undertaken to address fully the principal threats
posed by the remainder of the Site. This interim action is
consistent with any possible future actions because this action
calls for the removal of approximately 48 percent of the total
PCB mass in sediment from the estuary portion of the Site, which
acts as a continuing source of contamination throughout the
entire Site.

EPA recognizes that removal of the Hot Spot will not remediate
the estuary and lower harbor water quality PCB concentrations
below the Ambient Water Quality Criteria (AWQC). However, the
removal of the Hot Spot serves as a necessary first step for
achieving these goals.

EPA's rational for separating the Hot Spot into an operable unit
is to allow the removal of a highly concentrated mass of PCB
contamination from the environment. EPA believes this approach
is consistent with the operable unit approach in that it is a
discrete portion of a remedial response that eliminates a release
or threat of release of PCBs.

1-2
-------
Figure 1.1 at the end of this Section depicts the relationship
between the percentage of PCB mass and sediment volume in cubic
yards for the Upper Estuary. As the number of cubic yards
increases, the percentage of PCB mass per cubic yard decreases.
The rate of change in the percentage of PCB mass as it relates to
volume in cubic yards varies. At 4,000 ppm, or 48% PCB mass, the
slope of the curve changes dramatically. Above this point, the
rate of increase in percentage of PCB mass, as it relates to
sediment volume, markedly diminishes. By using a target level of
4,000 ppm, EPA will remove the greatest percentage of PCB mass
for the least volume of sediment. In EPA's judgment, removing
sediment at 4,000 ppm and greater takes advantage of the steepest
parts of the curve.

#**
Section 1 References

E.G. Jordan Co./Ebasco, 1989. "Hot Spot Feasibility Study for
New Bedford Harbor;" prepared by E.G. Jordan Co. for EPA.

Thibodeaux, 1989. "A Theoretical Evaluation of the Effectiveness
of Capping PCB Contaminated Sediment - New Bedford Harbor
Sediment.'1 (DCN #17)
1-3
-------
PCB
FIGURE 1.1
PCB MASS VERSUS VOLUME
100
80
60
40
20
10,000 cubic yards
0
0
50
100
150
200
250
300
Remediation VolUM, in thousand* of cubic yards
-------
SECTTOM 3.0 - RELIABILITY /VALIDITY OF DATA

2.1 USAGE ANALYTICAL DATA

2.1.1 TEST PROTOCOLS

DCN #1, Page 5
Itt::''chapter ay . the Agency 'grossly *:wca^
of the test data. Not. only are the test protocols and
analyses not all included or available for scrutiny, but it
is clearl from the extent to which we have been able to
examine any data, that they are not reliable and do not
provide a basis for action by the agency »

DCN #30, Appendix II, Page 35

The magnitude of the effort put into the project as veil as
designation of the New Bedford Harbor as a Superfund Site
should have justified and required the preparation of a site
specific Quality Assurance Project Plan (QAPP) covering both
the field and laboratory aspects of the project*... The
draft QA/QC plan was a good start, but did not qualify as a
formalized QAPP.

DCN #30, Appendix II, Page 38

Ideally, control samples for PCB projects should Be
completely free from electron-capture responsive components.
When "clean11 control samples are used, they serve as
excellent process blanks for the entire system, from "sample
collection through final analysis. Unfortunately this was
not the case, for this study. In fact, the chromatogram for
Control l Exhibit 27) suggests the presence of degraded
Aroclor 1260. As a consequence, the analysis of the 11
control samples served no useful purpose*

The two areas where this program appeared most deficient
were data validation and the lack of use of written standard
operating procedures which would have documented the
analysis protocol to be followed*
* •/ .'JH»0».XvW> s s ft *t * 't. •• '

The an||ylfilv';or'the EPA standard, reference materials
prcKiuc%l; acceptable results and the -percent, recoveries of
the Arqclbr 1260 spikes were reasonable for samples of this
type/ However, these accuracy assessments have very little
direct bearing on the accuracy of the actual samples. „ The
pattern alternations which gave rise to the quantitative
bids of the samples (the presence of new PCB congeners and
the sulfur interferences) were not present in the EPA
standard reference materials.
2-1
-------
EPA RESPONSE 2.1.1

The purpose of the Draft Quality Assurance/Quality Control
(QA/QC) Plan (which upon amendment became a working plan)
was to ensure data validity and to document the data quality
generated during the study period. The "Review of Hot Spot
Feasibility "Study" (DCN #12) by the PRPs states that,
"...the PCS concentrations reported for individual
subsamples in this (the COE) study are reasonably well
supported by laboratory Quality Control data..."

The purpose of the control samples was to demonstrate that
there was no significant cross-contamination of samples
during the air-drying process. A report from another
laboratory indicated that cross-contamination could occur
when high concentration PCB samples are dried in the
presence of low concentration samples. PCBs can volatilize
from the high concentration samples and then condense on the
low concentration samples, thereby contaminating them.
Great care was exercised to prevent this from occurring.
Fresh, uncontaminated air was directed over open containers
of wet samples by the use of cardboard baffles. Samples
were aligned in the direction of the air flow, with no
sample in front of or behind another, to avoid cross-
contamination. Each physical group of samples which were
air-dried in this fashion had one control sample associated
with it for the sole purpose of demonstrating that any
cross-contamination from volatilization and condensation
processes was insignificant. The average PCB concentration
of the eleven control samples was 0.01 ppm, ranging from a
low of <0.01 ppm to a high of 0.12 ppm. The sediment
samples, on the other hand, averaged 2,990 ppm, and ranged
from <0.01 ppm to 76,100 ppm. 60 of the 86 samples served
their stated purpose of demonstrating no significant cross-
contamination problems from the air-drying process.

EPA used standard operating procedures (SOPs) throughout the
execution of the analytical program. All data were
reviewed, or "validated" prior to release to the data user.

The analysis of spiked samples and of standard reference
materials (SRMs) was appropriate and has direct bearing on
the accuracy of the actual samples. Testing these QC
samples examines the entire analytical process, including
extraction efficiency, concentration of the extracts, sample
cleanup and chromatography, as well as quantitation and
reporting. Since the analytical method employed (USEPA
8080) would not quantitate *new" PCB congeners (e.g., those
arising from biotransformation processes), selecting a
different SRM for analysis would have had no impact on the
QA/QC program.
2-2
-------
2.1.2 ANALYTICAL METHODOLOGY

DCN #12, Page 4-5

Core samples were collected according to a systematic
sampling plan. However, the procedures used to select
subsamples for the cores (visual classification) for
determination of PCS content were subjective and probably
biased the results upward. The concentration results
reported for this study, therefore do flo£ reflect a
statistical design and are unsuitable for drawing inferences
about the distribution of PCBs within the estuary. The PCS
concentration reported for individual subsamples in this
study, are reasonably well supported by laboratory Quality
Control data. However, no field duplicates were analyzed
and no calibration data were provided to allow assessioent of
the correctness of the quantification*

OCN #30, Appendix II, Pages 40-41

The analytical methodology proposed for use in the study was
appropriate as was the instrumentation employed. The
quality of the data suffered, however, because the
prescribed sample clean up for sulfur removal was not used*

Peak resolution of the chrcmatogi^uns was poor. This
situation should not have had a negative impact on data!
quality, however, since both the standard* and the samples
should have been run under identical analysis conditions.
.•.•:•:•.-.•;:-.•:-:..•.•.- :...-.-.•:v>x-.-'.->:-x-.'X:>xx-X'Xv/.'Xv:'.-:-.-:-.w'' •:•••: :•.•.-. :•:•:•: :•.. :.•-•.:. •.-. .•••. x:-. •:•:.•- :•:•>.• >.•.•;•:.-.-.•.•.• ,• f.v tmiw fsfff ^w f ft f t t fff*ff * .w .-.•.

Poor peak resolution of the original chron^ogf^i'rp^exftnted
a problem as it. related to the pattern alternation r "
especially since the corresponding standards were not
available.; """"""""" """""""

Aroclor 1260 was found in four samples which came from three
different sampling sites. In addition, trace levels of
Aroclor 1260 were observed in eight additional samples.
Since there is no evidence of alteration of the Aroclor 1260
pattern, laboratory contamination is suspected as the source
of Aroclor 1260 in these samples.

Th«\qtS|p:'|;tation of the nev congeners formed during
biotrijpformation (which are not present in commercial
Aroclbr*mixtures) is beyond the scope of analytical method
(EPA Method 8080). Therefore, these PCBs were not included
in the total PCB data. When new congeners are present in
the samples, the data area biased low*
The QA/QC protocol apparently was not followed as itjrelated
to the clean-up of sample extracts for the removal of
2-3
-------
sulfur. As a consequence, sulfur interference was present
in 60 of the 85 sample chroma tograms (70%) .;

Chromatographic pattern alternations were
chromatograms * ' . ...................
The"- most "significant" Arbclbr " pa"€tern'" alteration"^
USAGE sediment; samples :is-, that ..due :ta;:.anaerob^ ""
dechlbrinatioiii
EPA RESPONSE 2.1.2

Sample clean-up for sulfur was employed as planned. If it
had not been performed, then approximately the first 10
minutes of every chromatogram would have been totally
obliterated by the sulfur peak(s). Since the chromatograms
are plainly readable and interpretable throughout their
length, it is obvious that the sulfur cleanup was performed,
and that the sulfur was almost entirely removed from the
sample extracts. The clean-up procedure is an iterative
process, and must be repeated several times before the
sulfur can be reduced to an acceptable level. Of the two
small sulfur peaks which might remain after this clean-up
was performed, the first, at a retention time (RT) of about
1.7 minutes, is well resolved from and occurs before any of
the peaks, and therefore was not an interference. The
second sulfur peak, at a RT of about 8.8 minutes, -co-elutes
with another PCB peak at about the same RT, and therefore
could, if present, exert a positive bias on the PCB value.
The sulfur clean-up was repeated on each sample extract
until either (1) the sulfur was totally eliminated from the
chromatogram, or (2) the sulfur was reduced to an
"acceptable" level, or (3) additional clean-up repetitions
resulted in no further reductions in sulfur levels. By
noting the size in area counts of the 1.7 minute RT sulfur
peak, the contribution of sulfur to the 8.8 minute RT PCB
peak can be approximated. All of the 86 sample
chromatograms were examined in this fashion to estimate any
positive bias to the PCB results from the presence of
sulfur. In several instances at the time of analysis, the
chemist eliminated the 8.8 minute RT peak from the
quantitation process because of the obvious presence of
sulfur. This approach resulted in 50 of the 86 sample
chromatograms (58%) being thoroughly free from sulfur
interference, while 33 of the remaining 36 sample
chromatograms exhibited a positive bias of only 5% or less
on the final PCB results. Therefore, 83 of the 86 sample
chromatograms (96%) were only minimally impacted by the
presence of sulfur with positive biases ranging from only 0
to <5%. Only three sample chromatograms had positive biases
in excess of 5% (two with 8%, and one with 15%). The

2-4
-------
average positive bias exerted on the final PCB results due
to the presence of sulfur in all 86 sample chromatograms was
less than 1%.

Peak resolution of the chromatograms was not poor.
Chromatographic "resolution" is defined mathematically as:

*R,1 - *R,2
0.5 (W, - W2)

where: *R,1 4tR,2 are the retention times in minutes of
peaks 1 & 2, and W, & W2 are the peak widths in minutes at
the bases of peaks 1 & 2 .

Resolution is a function of retention times and peak widths,
both time units. The PRPs1 process of altering the
horizontal axis of the chromatograms (akin to redrawing the
chromatograms at a different chart recorder speed), i.e.,
their so-called "resolution enhancement1* process, was purely
one of convenience to allow more facile visual comparisons.
The fact that the USACOE chromatograms compared well with
the PRPs1 after being compressed in this fashion indicates
that the resolution was indeed adequate to start with and
was comparable to the PRPs'.

EPA agrees that the analytical method employed here (USEPA
•Method 8080) will not quantitate certain PCB congeners which
are not present in commercial Aroclor mixtures. Even the
PRPs concede (DCN # 30A, Appendix II, Page 18) that the
method designed to quantitate certain PCB congeners (USEPA
Method 680) was not available at the time this study was
conducted. Method 8080 was the state-of-the-art technique
commonly utilized in th.e environmental analytical community
at that time. EPA agrees that the effect of using Method
8080 as opposed to Method 680 would be a negative bias. If
anything, repeating these analyses using Method 680 would
result in higher values for total PCBs.

A "visual classification" system was used to select
subsaraples from certain cores for chemical analysis. This
was performed under the personal direction of a Corps of
Engineers Waterways Experiment Station representative.
However, 18 of the 39 cores tested were sub-sampled on a
purely objective basis, using strata limits of 0"-12" and
12"-24". This was consistent with other sampling programs
conducted for the site.

One set of field duplicates was analyzed from grid number I-
11. Unfortunately, the depth strata subsampled were.
slightly different, with I-ll-l being subsampled at 0"-13"
and 13"-24", while 1-11-2 being subsampled at 0M-12" and

2-5
-------
12"-24". Thirteen additional grids had duplicate cores
sampled, but they were never analyzed.

Some "secondary" calibration data was provided in the
Condike June 1986 report, which the PRPs had access to, and
which would have allowed an independent assessment of the
correctness of the quantification. In addition, results of
split samples analyzed by another laboratory support the
accuracy of the quantification.

2.2 COMBINING DATA ACROSS STUDIES

DCN #12, Page 9

The: apprbach""tiakeh'" In" the Hot sp6t:''''Ke'p'6'rt^Is-fb'^
false assumption that the results of multiple studies f years
apart, using varying methods for sampling and analysis can
be viewed as a single coherent body of data. The Report
falls1 .--to; "p^byide^inforinatlon-'aboul: :the intent , purpose,, and
:Cl£cJc ••"of) ;,cstatistlcil design of the /studies from which the
data were drawn; It appears to assume that all of the
values used are equally accurate and that .inferences can be
drawn from the data set as a whole. This is not true,
especially because the underlying studies were not conducted
in accordance with statistically designed sampling plans.
Spot? Report also incorrectly
implies that the measureaents made in the various studies
jc set of aapsv '
EPA RESPONSE 2.2

The analytical data for the Hot Spot and the remainder of
the Acushnet River Estuary has been acquired over a period
of six years. The first sampling programs in the Acushnet
River Estuary identified an area in the northern part of the
Estuary with significantly higher levels of PCBs than the
remainder of the Estuary and Harbor. In 1982, sampling by
the U.S. Coast Guard confirmed this fact. The U.S. Army
Corps of Engineers (USACE) developed a program to determine
the nature and extent of PCB contamination within the
Estuary. The USACE developed a grid system for the upper
Estuary and performed three sampling events using this grid
system. The last sampling program, the USACE Hot Spot
sampling program (1988) , was confined to the Upper Estuary
in the location of the highest PCB concentrations and was
conducted to determine the nature and extent of the Hot Spot
areas. Thus, each sampling program built upon previous
sampling programs in an effort to delineate the boundaries
of the Hot Spot.

2-6
-------
To facilitate an understanding of the analytical data, the
PCB sediment concentrations were mapped. These maps
included all of the five data sets to provide sufficient
data. EPA believes that the data is of adequate quality to
be used for these purposes. Regardless of the difference in
sampling and analytical methods, each of these different
sampling programs have shown the same magnitude of PCB
contamination in the Hot Spot Area. In summary, EPA
believes that all of the values are of adequate quality and
demonstrate consistent results and can be used collectively
to define the extent of contamination and areas for
remediation. During the design phase, EPA will determine
the necessity of any additional sampling to further
delineate the actual limit of removal for plan and
specification development.

2.3 CONTOURING METHOD

OCN #12, Pages 9 and 10

The method used for contouring PCB analytical data froa
sediment samples (as outlined in the May, 1989 Feasibility
Study) is a simplistic approach based on arbitrarily-chosen
(from a statistical standpoint) contour intervals..,. Thi«
approach, while valid as a first pass to determine orders of
magnitude is entirely inadequate for more detailed* '
evaluation of analytical data.
The applied contour method Is not statistically rigorous and
does not adequately "weight the data for accurate assessment
of directional inhomogeneity (e»gv, non-random distribution
on contamination) . This simplistic approach has purposely
not accounted for the factors which provide "fabric11 or
linearity to these data, such as tidal currents, ongoing
sedimentation, and channeling thereby simply cutting across
these natural bounding conditions;

The use of only three contour levels with an arbitrary upper
f 47000, ppm PCB has masked many cruci'al details
which •'Mp*'provjCd* insight, into the ongoing dynamic movement
of PCBBkVJthin' the sediment and water column. A nore
approprfate contour interval night be half -step log
intervals (Ue., Q-50, 50-100, 100-500, 500-1,000, 1,000-
The Feasibility' Study. contouring approach does not
incorporate a linear regression analysis to correlate PCB
concentration with distance down the primary transport
pathway. This information is useful in assessing the
directional inhomogeneity of the data. A linear regression

2-7
-------
analysis might also help to identify any non-"hot spot"
sources of PCBs into the estuary.

Accurate "assessment of sediment volume falling above ai given
lower contaminant threshold is impossible utilizing the
Feasibility study approach. Given the projected costs of
remediation for the "hot spot11 ($10-15 million) r an error of
15-20%i in: contouring accuracy could result in errors in
projected expenditures of several million dollars,

The simplistic contouring approach provides no measure of
uncertainty in the contoured data and it provides no means
for determination of the adequacy of .sampling density*

A statistical approach known as kriging could adequately
address these issues by assigning preferred fabric or
linearity to data, thereby accounting for directions if
inhpmo^eneityr; ..... " ........................... ......................
:':'prbvide '''a ''minimum '''variance, unbiased linear
estimator of the distribution of PCB contamination between
any two points of known value in any given geometry* In
addition, it can provide an .explicit measure of uncertainty
in the contoured data by incorporating error bands on all
contours and if more data are needed, kriging will provide
guidance for optimum placement of additional sampling
stations;;
EPA RESPONSE 2.3

The contour method used in the FS is an adequate method for
a first pass at data interpretation. This method is also
acceptable for volume determinations where sufficient data
exists. This contouring procedure was used in 1986 and 1987
to plot the original data sets to conceptualize the nature
and extent of the PCB distribution. Where natural boundary
conditions were known to occur, the contour placement was
adjusted in these areas to prevent crossing of these
boundaries. Subsequent sampling by the USAGE in 1988
confirmed that these contour maps did, in fact, present an
accurate interpretation of the distribution of PCBs in the
Upper Estuary.

The density of the data points in the Hot Spot Area is a
critical factor in determining whether the method of
contouring used is an acceptable method for volume
calculations. More than 75 samples have been taken in and
around the Hot Spot to determine the PCB concentrations and
delineate the boundaries of contamination. As illustrated
in Figure A-1A of the Hot Spot Feasibility Study (HSFS), the
majority of the sample locations lie within 200 feet of each

2-8
-------
other. Many of the sample points are closer, within 100
feet. Even if a few of the data points are plotted
incorrectly, interpolating data at this density is
sufficient to calculate sediment volumes. In addition,
factors such as tidal currents and channeling become less
important as the points are closer and limited cutting
occurs across these natural boundaries.

Several contour maps were developed with different contour
intervals. The map selected for the HSFS presented four
contour intervals: 0-50 ppm; 50-500 ppm; 500-4,000 ppm; and
over 4,000 ppm. This map was selected primarily because
additional contour intervals did not aid in illustrating the
relationship of the Hot Spot to the remainder of the
Estuary.

EPA believes that the estimated Hot Spot volume using this
contour method is accurate for its intended use given the
amount of sampling points used to define the Hot Spot Area.
EPA recognizes that uncertainties associated with this
volume estimate may impact the cost estimate of the remedial
alternatives. However, the magnitude of this uncertainty is
expected to fall within the +50% to -30% range for
feasibility study cost estimates (Guidance for Conducting
Remedial Investigations and Feasibility Studies Under
CERCLA, October, 1988).

Kriging is another method for calculating PCB confours that
is used where there is less data and interpolation is
occurring -between data points separated by significant
distances. With respect to the Hot Spot, EPA believes that
sufficient sampling has occurred such that the use of either
method (i.e., contouring or kriging) would generate similar
volume estimates.

The PRPs' generated a contour map using EPA's data and it is
presented in Figure 2.1 at the end of the Section.
According to the PRPs, the kriging method produced results
that, "represent reliable estimates of constituent masses
and deposition in New Bedford Harbor upper Estuary sediment"
(Balsam, 1989a). The PRP map (Figure 2.1) shows a similar
extent of PCB contamination when compared to EPA's contour
map (Figure 2.2). Both of these maps are validated by the
PCB sediment sampling and analytical results from the thin
layer sampling program conducted by the PRPs (Balsam,
1989b).
2.4 DATA HOT INCLUDED IN HOT SPOT PS

2.4.1 BASELINE ENVIRONMENTAL RISK ASSESSMENT

2-9
-------
DCN #31, Page 4-1

The HSFS specifically references a baseline risk assessment.
Although the HSFS states that the environmental- risk
assessment "is scheduled for completion in the summer of
1989,";; the document has not yet been released. ..^ Without
this document, defendants are unable to examine a critical
piece .in. EPA.'s, purported, justification ..for:..dredgtinfithe hot
EPA RESPONSE 2.4.1

EPA did examine the baseline environmental risks associated with
the Hot Spot area sediment as part of Hot Spot Feasibility Study
(HSFS). EPA is currently examining the baseline environmental
risks for the entire site as part of the second operable unit.
Results of this study are scheduled to be available in April
1990.

The following is a brief summary of the HSFS environmental risk
assessment presented in the HSFS. The risk assessment evaluated
the potential risk to biota from both exposure to the water
column and direct contact with the sediment. To evaluate the
water column route of exposure, PCB water column data was
compared against the Ambient Water Quality Criteria (AWQC) value
of 30 parts per trillion. This AWQC value is a residue-based
criterion that was developed to provide protection to aquatic
biota under chronic exposure conditions. In the vicinity of the
Hot Spot, water column PCB concentrations in excess of 100 times
the ^AWQC value have been measured in studies conducted for EPA
(Battelle, 1989) and by the PRPs (ASA, 1989).

The environmental evaluation of the Hot Spot sediment consisted
of a comparison of estimated pore water PCB concentration against
the AWQC using the Interim Sediment Quality Criteria (SQC) method
and comparison of site-specific toxicological data (Hansen,
1986) . The probability of the Hot Spot pore water PCB
concentration exceeding the AWQC was approximately 100 percent.
This result was consistent with the site-specific toxicological
data that demonstrated the upper estuary sediment region to be
toxic both for benthic invertebrates and fish.
2.4.2 SEDIMENT QUALITY DATA - 1987 HOT SPOT SURVEY

DCN #31, Page 4-2
attempted to procure
the full loratbry database utilized to define the «!hot
2-10
-------
EPA RESPONSE 2.4.2

Over the period of several months, EPA provided the PRPs with 3
copies of the Hot Spot sampling report prepared by the Corps of
Engineers New England Division (NED). The report contains
information describing the sampling and the analytical programs
conducted in 1987 by NED to develop a more definitive picture of
PCB contamination within the upper portion of the Estuary.
Sampling information included the location (latitude and
longitude) and the specific depth of each sample. The analytical
program was conducted to provide a physical and geochemical
description of the sediments. Physical measurements included
moisture content, grain size distribution, specific gravity, and
Atterberg limits. The geochemical characterization included PCB
and total organic carbon (TOC) analyses.

The actual (PCB) chromatograms and associated laboratory backup
QA/QC information are not routinely considered a part of EPA's
Administrative Record for a site. However, in the interest of
continued information exchange with the PRPs, EPA, with the
assistance of NED, produced a majority of this raw laboratory
material on October 23, 1989. The Corps is continuing to search
for the remaining chromatograms, to determine if they are still
in existence.
2.4.3 AIR QIBH.TTY DVTX

DCN # 31, Page 4-3

only very limited air quality data collected during the
pilot dredging program have been made available*

EPA RESPONSE 2.4.3

EPA's contractor has made the PCB chromatograms and associated
QA/QC information from the Pilot Study Air Monitoring program
available to the PRPs (see DCN #40).

Presently, this data is undergoing data validation. Once
validated, the data will be incorporated into the Pilot Study Air
Monitoring report. This report will be used in EPA's predesign
studies to evaluate the air monitoring and emission control
requirements for the dredging and dewatering activities prior to
the preparation of plans and specifications. The current
schedule calls ^for this, report to be completed by April 30, 1990.

For additional information on volatile PCB emissions, refer to
EPA Response 4.3 in Section 4 of this Responsiveness Summary.
2-11
-------
2.4.4 TOXICITY DATA

DCN #31, Page 4-4

Toxicltv Data. EPA conducted toxicIty data evaluation on
biota during the course of the pilot dredging program.?
Defendants ...were not provided with; the;.:.results5V:,::|'':' ••••••••••••••"•"•-•-••

EPA RESPONSE 2.4.4

The results of this portion of the monitoring program are
summarized in the Corps of Engineers Pilot Study Interim
Report. Several technical papers on this subject are
currently being prepared by EPA's Narragansett Laboratory,
but are not yet complete. This comment is further addressed
in EPA Response 8.8 in Section 8 of this Responsiveness
Summary.

2.4.5 CDF STABILITY DATA

DCN #31, Page 4-4

CDF stabil1ty Data. The Pilot Dredging[Program-work pian
called for the collection of data on the stability-of
CDF ; since: its construction. • None..of, the .data..^...have:;
''••
EPA RESPONSE 2.4.3

An Appendix to the final version of the Pilot Study Report
will address CDF dike design and construction in greater
detail. This report will contain the data obtained while
monitoring the in-water dike portion of the CDF. This
comment is further addressed in EPA Response 8.13 in Section
8 of this document.
2.4.6 PILOT DREDGING OPERATIONAL DATA

DCN #31, Page 4-5

Pilot Pyedoing Operation Data> Neither the pilot dredging
report nor the Administrative .Record includes operational
data or daily logs compiled during the course of the pilot
study. Defendants believe that such information is crucial
to the overall evaluation of dredging and a remedial^action,
2-12
-------
EPA RES?QNSB 2.4.6

The pilot study report contains a detailed summary of daily
operations which include how the dredges were operated
(swing speed, cutterhead rotation, etc.) hours operated per
day, downtime per day and dredge location. Very little
additional information can be obtained from reviewing
contractor daily reports and logs kept by government
personnel. However, this information has been added to the
Administrative Record as item 4.4.27.
2.4.7 RESULTS MEETING DECISION CRITERIA

DCN #31, Page 4-5

The pilot dredging report Indicates that the goveriOTehi:
ignored its own procedures. At the bottom of page 44, there
is discussion of results, despite the fact that SOB*
criteria were reportedly violated on several occasions*

DCN #31, Page 5-37

The operations of the Decision committee and review of datai
did not follow the plan or the procedures that the public
were told would be followed.

EPA RESPONSE 2.4.7

Pre-operational monitoring was used to establish background
conditions in the harbor. The decision criteria consisted
of a set of numerical criteria that were established to
serve as an early warning mechanism that, if exceeded, would
require adjustments in the project. The criteria consisted
of contaminant levels and biological responses that
represented a statistical or biologically significant
increase over background conditions.

A decision committee, headed by EPA with representatives
from the appropriate state and Federal agencies, evaluated
monitoring results. Data was provided to the committee less
than 24 hours after sample collection, allowing for timely
adjustments to pilot study operations.

The chemical criteria were exceeded on only 2 occasions and
biological criteria were not exceeded during the project
period. On days when the criteria were exceeded, the EPA
project manager contacted committee members to discuss the
situation. Extreme weather or obvious operational problems
were encountered on days when criteria were exceeded. This
resulted in the committee deciding to continue operations

2-13
-------
and monitoring with appropriate changes to the operations.
The instances when the criteria were exceeded were all one
day spikes with the following days' contaminant levels
returning to the range of background conditions.
###

Section 2 References

ASA, 1989. "Tidal Cycle Flux Measurement Data," (DCN #21).

Balsam, 1989a. "A Remedial Action Program - New Bedford
Harbor Superfund Site, Attachment A, Acushnet River Upper
Estuary PCB Mass," (DCN #16).

Balsam, 1989b. "A Remedial Action Program - New Bedford
Harbor Superfund Site, Attachment D, New Bedford Harbor Thin
Layer Sampling Program," (DCN #19).

Battelle, 1989. New Bedford Harbor Database (hard copy
printout), prepared for Ebasco Services, Incorporated.
2-14
-------
N
FIGURE 2.1
LCGQB

\00— .TOTAL PGB CONCENTRATION ISOPUTTH (PFU)

. * . " . - SALT
OCMOAKD U9N6 MTERPOLATION V DATA TOM
UMTfB STATES AMIT COWS OT CHONCUtS
(AUOUKT-OCTOaCR IMS AND AUGUST IM7)
AND •ATTfUOMII (JUNC 1M0)

^BALSAM
nHK^X O4VWONUDITAL CONSULTANT* MC.
M STIUS NO. SAUM. MK 0307t
OATC
10/1 2/B9
SCAU
r-wxr
MAIM »Y
D.J.H.
«*N* MT
•2*21««
OCOXD
GJI.C.
APTMMD
UOS
CIJEHI
AVX CORPORATION
nn£ HOPIXTMS ra»
TOTAL POI
CXMMXMWADONS
«r-ir MKMVM.
MOJCCT
NEW BEDFORD
^^ HARBOR
1.5 1 6292.05
-------
FIGURE 2.2
tsi
I
1' . 11 . n •—!* i—B—i—t I I' i—U—"—!*-;-i-
INTERPRETATION OF
TOTAL PCB CONCENTRATIONS-
DEPTH: ZERO TO 12 INCHES
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOR
• SUM OF AVAILABLE AROCMLOM DATA
-------
SECTION 3.0 ~ RISK ASSESSMENT

3.1 ADDITIONAL CONTAMINANTS OF CONCERN

DCN #5, Page 5

On pages 2-10 and 2-11, it Is asserted that risks from
metals and PAHs have been analyzed and reported on in the
Baseline Risk Assessment. This assertion is incorrect. Ho
analysis from risks of either has been done, and, indeed,
contrary .to the statement at page 3-1, that a Baseline
Environmental Risk Assessment is scheduled for completion in
the summer of 1989, no such document has been issued.

DCN #6, Page 4

For thefNew Bedford Harbor risk characterization, and as
noted above, only PCB exposures estimated in the RA are
being considered in this critique, although other toxicants
are;found in the harbor; These include a variety of Oil and
Hazardous Materials (OHMs) as well as metals (e.g. other
hazardous materials) such as copper, lead and cadmium.

DCN #31, Page 3-3

On page 2-14, Ebascb states that "Exposure to PCBs was
evaluated for all routes of exposure. When or if the
exposure levels for PCBs were considered insignificant,
exposure to cadmium, copper, and lead was then evaluated,1*
Such a selective approachr especially in combination with
EPAfs^eciislb^ aromatic
hydrocarbons ;in:the?harborthat will still be there after
dredging, clearly demonstrates that EPA's goal is not
accuratei£:::,.£o;va_s^ to go,forward with
dredging^""""""" """"""" """""•""'•'"••"••' -•"•" ""•--' -•••••-••

EPA RESPONSE 3.1

PCBs are the primary contaminant of concern in the Hot Spot
area and Estuary. However, even if the Acushnet River
Estuary were not contaminated with PCBs, it would by no
means be a pristine estuarine environment. It has
historically been polluted with industrial and sanitary
waste discharges. Due to these discharges, there are
elevated levels of polycyclic aromatic hydrocarbons (PAHs)
and heavy metals (i.e., copper, chromium, lead, and cadmium)
in the estuary sediment.

The potential risk associated with exposure to other'
contaminants present in the harbor was evaluated and

' 3-1
-------
discussed in the Baseline Public Health Risk Assessment (see
page 1-2) which was released in August 1989. The Baseline
Environmental Risk Assessment for the overall site is
scheduled for release in April 1990.

The highest metal-contaminated sediment is not co-located
with the PCB Hot Spot Area. Rather, its location correlates
with the location of industrial discharges and/or combined
sewer overflow discharge pipes. Contamination, such as
heavy metal contamination outside of the Hot Spot will be
addressed in the second operable unit.

EPA has found PAH compounds to be generally co-located with
PCBs. However, the range of PAH concentrations in sediment
was significantly less than the range of PCB concentrations.
Total PAH concentrations range from below detection limit to
930 ppm, with an average PAH sediment concentration of
approximately 70 ppm. (The highest PAH concentration of 930
ppm was detected in the Hot Spot area of the upper estuary.)
No discrete areas of elevated levels of PAH compounds were
observed, suggesting that PAH contamination results from
non-point sources such as urban runoff. PAH concentrations
detected in New Bedford Harbor sediment are similar to PAH
concentrations detected in other urban and industrialized
area (EPA, 1982).

The relative toxicity of PAH compounds with respect to PCBs
indicates that the majority of risk from exposure to
sediment can be attributed to PCBs. Since PAH compounds can
be effectively treated by the technologies used to treat PCB
contamination, methods taken to reduce PCB contamination
will effectively reduce PAH contamination (E.G.
Jordan/Ebasco, 1989). However, unlike PCBs, the occurrence
of PAH compounds is expected to continue after remediation
due to non-point sources. Therefore, the remedial actions
planned in this operable unit may not permanently reduce
levels of PAH contaminants.
3.2 EXPOSURE ASSUMPTIONS

3.2.1 Methodology

DCN 16, Page 2

As a whole, the RA seeks to apply unreasonable and overly
large estimates of exposure....

DCN #6, Page 1

I do not believe that these estimates are realistic o*r even
correct. As to their correctness, they appear to be

3-2
-------
mathematically consistent but I conclude they are
substantial overestimates of exposure opportunity, exposure
dose and as a consequence, they misstate the true risk. :

DCN #8, Page 1
The '"iha j.or'r:£!aws-''ideri^^
1."", The findings'"''frOT:::f'^'e:;MTn1Freport are not properly
"" abstracted into the executive summary.
2."" The assumptions^:;:regarding>..^frequency of exposure are
absurd* """""" '"'""'"' "'" """"
3. other assumptions""used""in'""the calculations are not
supported by the literature^

DCN #31, Page 3-10

EPA'i..."Guidelines' for Exposure Assessment encourage the use
of; realistic assessments based on the best data available.
Worst-case estimates are not encouraged (EPA 1986b), -
Nonetheless,;EPA: ignored its own guidelines in performing
the exposure assessment and instead manufactured potential
risks by linking together a series of implausible worst"
case exposure assumptions. As set forth below, the New
Bedford Harbor risk assessment has failed to demonstrate the
reasonableness of key assumptions and evaluates exposures
that are unlikely to occur; potential risks that are
estimated for the site are calculated under the terms and
|wditi^^^ scenarios.
EPA RESPONSE 3.2.1

The Baseline Public Health Risk Assessment (RA) was
conducted in accordance to the guidelines presented in the
Superfund Public Health Evaluation Manual (SPHEM) and the
Superfund Exposure Assessment Manual (SEAM). The exposure
parameters used in the RA were obtained from EPA documents
and the scientific literature or developed based on
professional judgement. Detailed rational and appropriate
citations for the methodology and exposure assumptions used
were provided in the RA text. Each exposure parameter was
reviewed and considered to be consistent with exposure
parameters used in other Superfund Risk Assessments. EPA
made every attempt to obtain and use realistic exposure
assumptions. Comments specific to each route of exposure
are discussed in the following sections.
3-3
-------
3.2.2 Direct Contact Route of Exposure

DCN #6, Page 3

Based on personal observation of the area by this reviewer,
namely, the low lying mud flats which are adjacent to the
harbor and the Aerovox/AVX facility as well as the
surrounding property, it is my opinion that few persons of
the kind described by the RA as being at particular risk are
likely to be attracted to the sediments in this area for any
legitimate: or recreational purpose*

DCN #6, Page 10

The most contaminated material in the harbor is said to be
the sediment and mud located in the northern part of the
harbor. The highest degree of contamination is most
frequently underwater and unlikely to be accessible to
children, large or small. Access to this area is highly
limited arid the postulated significant contact with highly
contaminated materials is no£ likely to occur a*'-.the; levels
or with the frequency listed in the RA|

DCN #31, Page 3-7

When the results of Table 2.1 are compared with sediment
concentrations of PCBs used in the risk assessment (risk
assessment Table 2-5), it appears that the concentrations of
PCBs in sediment* at locations at which period
can be expected have been greatly inflated in the risk
assessment*. "'

DCN #31, Page 3-23

The amount of soil or sediment clinging to skin per day is
known as the deposition rate. With only a substantive
notation that sediments might adhere to skin more than
soils, Ebasco chose an upper range value 3 times higher (1.5
mg/cm) than the EPA»s conventionally acceptable default
value (0*5 mg/cm}, which is supposed to be applied in lieu
of more adequate, information ;s
AfXwK- *•* w. w v .v .-.•.:•.••.• .-..•:•.-.• .. •.•• ...•;.;.:.•..•.•

DCN #31, Page 3-14

Considiflng the length of time that field work has been
performed by EPA at this site, field observations of
activity patterns at the actual exposure points should be
available* The selection of Marsh and Palmer Islands as
potential exposure points is inadequately supported*
3-4
-------
DCN #31, Page 3-21

The risk assessment uses the unreasonable assumption that
young children will be exposed to sediments at the more
limited access areas of the harbor (Marsh, Popes, ', and Palmer
Islands) which do not have public beaches as often as they
would be exposed at the public beaches. (Forts Rodman and
Phoenix)! 'yjo;.;,^

EPA RESPONSE 3.2.2

The direct contact exposure scenarios were based on the
observations about the land use around the study area and
results from the study titled "The damages to Recreational
Activities from PCBs in the New Bedford Harbor," prepared by
the University of Maryland for NOAA. This study indicates
that the local population uses beaches along Areas II and
III. However, access to Area I is not totally restricted
and a subsection of this area is located next to a
playground. Therefore, it is reasonable that exposure could
potentially occur in this area. Acknowledging the fact that
the frequency of exposure to this area may be less than in
the beach area, the RA assumed a lower frequency of
exposure.

EPA recognizes that some of the exposure scenarios developed
for the direct contact route for the Hot Spot were
conservative. However, EPA has examined a less conservative
exposure scenario which is mentioned in Section VI.C of the
Record of Decision. Based on this assessment, EPA concludes
that significant public health risks still exist.

Moreover, the approach used to develop the RA scenarios is
consistent with EPA policy as stated in SPHEM:

The Superfund risk assessment process is based on concern
for both individual risk and risk to exposed populations.
One exposure point that should be evaluated for a pathway is
the geographic point of highest individual exposure for a
given release source/ transport medium combination (i.e.,
the geographic location where human inhabitants are exposed
to the highest predicted chemical concentrations). Exposure
points with lower predicted chemical concentrations and
large potentially exposed populations should also be
evaluated.

EPA evaluated direct contact and incidental ingestion
_ exposure to sediments since Marsh, Palmer and Popes Island
are locations within the study area that are easily
accessible and since adults, older children and young
children have been observed in these areas. The exposure

3-5
-------
frequencies assumed for these areas (20 and loo times per
\ year) correspond to 1 and 5 exposures per week for the six
months when outdoor activities are likely to occur. Based
on the land use at these locations, these exposure
frequencies were considered appropriate.

3.2.3 Incidental Ingestion

DCN #6, Page 11

Controversy exists over the d«gre« ' to which young and older
children ingest sediments, dirt and other materials in their
hone and play environment. The RA goes to secondary sources
to choose an applicable value for "pica" type dirt and
sediment exposure. The value used, 0.5 g per exposure,
developed by LaGby in 1987, is still considered by some to
be excessively large. Recent EPA. guidance indicates that
200 mg per day may be an acceptable estimate. The stated
value may be more appropriate for household dust and
backyard dirt but is less likely to be true for soils,
sediment or mud derived from hydrated soils found in Hew
Bedford Harbor. The true value is likely to be less than
500 mg in any case.

DCN #6, Page 20

Among the spread sheets provided by the EPA and B.C. Jordan,
Table C-101 (which doe* not appear as a separate table; in
the RA) purports to correctly calculate the risk from daily
ingestion of sediment by a child. This table includes a
"most probable** ind "realistic worst1* case scenario. Both
of these are wrong and over stated. The area considered is
the cove area and the values chosen for the combined
estimate, namely sediment ingestion and contact, are likely
to overestimate risk by a factor in excess of 25,000«

DCN #31, Page 3-22

A sediment ingestion rate of 500; mg/day was selected for
young children (ages 1-6) despite the fact that EPA Guidance
(1989) recommends the use of 200 mg/day (page 2-26). Use of
a sediment ingestion rate more than double EPA's own
recommended rate is counter to EPA's Guidelines for Exposure
Assessment's recommendation of realistic, not worst-case
estimates*
EPA RESPONSE 3.2.3

As stated in the Risk Assessment text (Page 2-26):

3-6
-------
A review of the literature indicated that between 100
to 500 mg of sediment per exposure is a reasonable
estimate for sediment ingestion by children less than 5
years old (LaGoy, 1987). Recent EPA guidance suggests
an ingestion rate of 200 mg/day be applied to exposures
concerning children between the ages of 2-6 years (EPA,
1989). This risk assessment was conducted prior to
release of this guidance, and a value of 500
mg/exposure was assumed as the amount of sediment
ingested. This is the upper end of the range of
estimated values and will provide a conservative
estimate of exposure.

However, in response to the comments which it received on
incidental ingestion, EPA decided not to include incidental
ingestion in the less conservative exposure scenario used in
the Record of Decision. Nonetheless, EPA does not consider
it appropriate to alter its conclusion that significant
public health risks exist.

EPA will evaluate various ingestion rates during the
development of target clean-up levels for the second
operable unit.

3.2.4 Ingestion of Lobster Hepatopancreas fTomalley)

DCN #6, Page 12
6

The magnitude of the derived risk for the ingestion route of
exposure is driven by the inclusion of tomalley (lobster
hepatopancreas} with its concentration of PCB content
(Pruellr et al. 1988). The deletion of this factor or
modification of the estimated uptake from this source vould
result in a reduction in exposure in children and adults by
at least a factor of 6.2. If the tomalley is not
considered, then lobsters taken from Area III would meet the
applicable FDA guideline. Even a lobster taken from Area I
would meet the FDA criteria if whole body PCB concentrations
are determined (1131.4 ppb or 1.13 ppm In a large lobster
taken from Area I, according to Hillman, et al« 1987)*

DCN #15, Page 5-8

Anaiyleiror lobster tomalley (liver) reported higher PCB
concentrations than, in lobster muscle* If lobster tomalley
were not considered edible, lobster.caught from throughout
the New Bedford Harbor area would also contain less PCB than
the USFDA permissible level. If lobster tomalley is
considered edible only lobster from areas one and two/ as
shown on Figure 5-1 would exceed USFDA PCB levels (Eb'asco,
1989} .

3-7
-------
EPA RESPONSE 3.2.4

The Greater New Bedford PCB Health Effects Study indicates
that 42 percent of people who eat lobster also consume the
tonalley. Since PCBs tend to bioaccumulate at higher
concentrations within the tomalley, conservative estimates
of exposure need to include all edible portions of the
lobster. Inclusion of the tomalley is consistent with the
FDA guideline for the analysis of the edible tissue portion
of lobster.

The FDA's position is based on the fact that once a lobster
is placed in commerce, the consumer has no way to identify
its source. The FDA regards the exclusion of the tomalley
from its standards an impracticable idea which would not
adequately protect the consumer.

However, the FDA's limit is not solely health-based. EPA
views this fact as significant. The FDA considered, as
required by statute, factors such as the economic impact
likely to be experienced by affected members of the food
industry in establishing tolerance levels. In addition, in
defining its standards, the FDA used consumption levels
based on national per capita rates. EPA believes
consumption levels in New Bedford Harbor are likely to be
differ, based in part, on the Greater New Bedford PCB Health
Effects Study and New Bedford's proximity to the coast.

The laboratories of the Commonwealth of Massachusetts, under
the guidance of FDA's Regional Laboratory, have included the
tomalley in all their lobster analyses from 1981 through
1986 (Table 2-8 of the RA). The results of the analyses
have consistently detected exceedances of the FDA 2 ppm
tolerance limit in portions of Buzzards Bay. These areas
include Areas II and III of the DPH fishing closure areas.
EPA's analyses of lobsters from these areas collected in
1987 also found exceedances of the 2 ppm limit. Analytical
results of the 1984 and 1985 sampling conducted by Battelle
showed somewhat lower levels (Hillman, 1987). However, the
analyses was not performed using the FDA method, and the
tomalley was not included. EPA has calculated the edible
portion concentrations using the methodology presented on
page 2-31 of the Baseline Risk Assessment for the DPH
fishing closure areas. The results for Areas I and II are
in excess of the FDA limit, 7.6 ppm and 2.3 ppm PCB
respectively, while Area III is below the limit at 1.43 ppm.

A full evaluation of a goal for protection of public health
will be completed within the second operable unit
feasibility study.

3-8
-------
3.2.5 Consumption of Seafood

DCN #6, Page 20
The issue of exaggerated fish consximptibh''''patt'eCTsV:'By:%:¥dult;s
and children, , the specific fish availability with its degree
of contamination and the calculation from this set of
assumptions that there now exists an increased risk of
cancer as a result leads the RA to conclude that a
substantial cancer risk does exist from this exposure
pathway. However, in the opinion of this reviewer, the
evidence accumulated to date on this subject is far from
conclusive.
DCN #8, Page 9
local seafood eaten. "These values were decided after a
review of the literature failed to provide a site-specific
value applicable to recreational consuinpt ion of fish and
shelif isht*^ of literature exists which
indicate :-v'tJiai?5-f;ish:r'ebnsumpt'iori/ by adults is between 6-14
g/day divided between locally caught and commercial
products. However, EBASCO decided to use 227 g on a daily
basis as one assumption.

DCN #31, Page 3-25
4
No evidence was presented in the risk assessment to 'support
the contention that an individual, could or would reasonably
catch all of, their dietary seafood from the estuary or upper
harbor. In the absence of a supporting discussion, the EPA
should have used a dietary mixing factor (EPA 1989} to
account for a reasonable portion of the seafood diet that
would be expected to be acquired in the estuary or upper
harbor. ... As discussed in the Greater New Bedford Health
Effects Study , only about 15% of the local population
reported eating seafood two or more times per week. Thus,
average consumption could reasonably be estimated to be
about one meal per week. Assuming that a single serving of
seafood is about 114 g (PTI 1987), average consumption could
be about ^20 g/day, which is also the default value
reconmejided by MDEQE (1989). EPA (1989) presents average
seafood consumption rates of 6.5 to 37 g/day. The risk
assessment used a typical consumption rate of one 227 gram
meal of fish per week, equivalent to a daily rate of 32
grams/day.
3-9
-------
EPA RESPONSE 3.2.5

Since there is no widely accepted value for recreational
fish and shellfish consumption, EPA chose to use 8 ounces
(i.e., 227 grains) as a standard value for each fish meal,
and vary the number of fish meals consumed per year to
provide a range of exposure frequencies.

The use of 227 grams/meal corresponds to the following
average daily intake values:

227 grams/meal - monthly consumption » 7.5 g fish/day
227 grams/meal - weekly consumption - 32 g fish/day
227 grams/meal - daily consumption * 227 g fish/day

EPA considers this range of consumption values appropriate
for this site as this value reflects the range of values
cited in the literature. Although EPA recommends the use of
the average value of 6.5 g fish/day, the Superfund Public
Health Evaluation Manual (SPHEM) also states that "...higher
than average fish consumption may be important for some
sites where surface water contamination is a problem.1*

Consumption values cited in the literature range from 6.5 g
fish/day used by EPA in its Ambient Water Quality Criteria
to 18.7 g fish/day cited by Cordel, et al. (1978). (These
values correspond to 10.5 and 30 8-ounce fish meals per
year, respectively.) The Environ (1985) report discusses
the limitations of these values and recommends using 14 g
fish/day (22.5 8-ounce fish meals per year) as a reasonable
average daily fish consumption by freshwater recreational
fishermen.

The frequency with which children eat lobster in New Bedford
Harbor is not available although the Greater New Bedford
Health Effects Study does report that individuals consume
locally caught seafood. There is no data to indicate that
children do not eat lobster. In the absence of scientific
data and in accordance with EPA's Guidelines of 1986, EPA
has made the conservative assumption that children might eat
lobster.

3.2.6 Uncertainty Analysis

DCN 131, Page 3-2

Each of the assumptions used in a risk assessment; is more or
less uncertain and therefore introduces uncertainty into the
final estimates of risk. The New Bedford Harbor risk
assessment fails to adequately characterize the orders of
magnitude of uncertainty in the estimates of risk presented
by the hot spot operable unit. The discussions of risk in

3-10
-------
the risk assessment and the HSFS imply a severe and present
danger to public.health and fail to acknowledge that
estimated risks are based on the assumed conditions of
arbitrary exposure scenarios that apply only to a
hypothetical population, not real people who liyeyahdr worK
in the City of New;Bedford. The
conservative assumptions that^greatly
DCN #31, Page 3-10
presented In Chapter
2 are for -the entire Greater New Bedford area, and are
inadequate to characterize activities that may occur at a
discrete location-;/'""""" ............
EPA RESPONSE 3.2.6

The RA states that the exposure scenarios evaluated are for
the "hypothetical" individual under the specified exposure
conditions (Page 2-18):

These scenarios do not predict the number of people who
may be exposed to contaminants in the Greater New
Bedford Area, but rather provide an estimate of the
magnitude of exposure that could be incurred by an
individual receptor under specified exposure •
conditions.

The uncertainties associated with estimating exposure result
from quantifying parameters that are not directly observed
(e.g., frequency and duration of exposure). Because some of
these parameters are functions of the behavior patterns and
personal habits of the exposed populations, no one value can
be assumed representative of all possible exposure '
conditions. To account for some of this variation, exposure
scenarios were developed based on a range of exposure
frequencies and durations. For some exposure scenarios, the
range of exposure parameters spans two orders of magnitude.
EPA assumed that the actual exposure encountered by any
individual receiving exposure would fall within this range.

There are also uncertainties associated with assigning
quantitative values to exposure parameters, such as body
weight, ventilation rate, surface areas, and absorption or
toxicokinetic factors (TKFs). The parameters used in the RA
exposure assessment were based on literature values and
professional judgement. Therefore, they may not be
representative of each and every individual in the New
Bedford Harbor area. However, EPA does not consider the
parameters as misleading, and believes the exposure

3-11
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scenarios represent realistic probabilities for the New
Bedford population. Moreover, any uncertainties associated
with assigning values to these parameters are estimated to
be less than one order of magnitude.

3.2.7 Airborne Route of Exposure

DCN 131, Page 3-8

The risk assessment inappropriately characterized ambient
air concentrations of PCB». Only limited air data were
available to assess risks associated with inhalation
exposure to PCBs. As a result PCB concentrations in air
above the mudflats in the estuary were used to characterize
ambient air concentrations at other locations in the Hew
Bedford area. The risk assessment acknowledges the
inappropriateness of this approach (pp. 2-34 and 4-50), yet
posits estimates of potential risks using the mudflat
ambient air data nonetheless. ' "'"""

EPA RESPONSE 3.2.7

The Baseline Risk Assessment did evaluate the potential
risks associated with exposure to airborne PCBs. The PCB
value used in this assessment was 10 ng/m3. This background
value represents observations from several studies in the
New Bedford area. The results of assessment indicated a
lifetime potential risk of 8X10**, assuming a 70-year
exposure duration. This value is at the low end of EPA's
target range.

3.2.8 Dermal Absorption of PCBs

OCN 131, Page 3-30

The risk assessment uses the assumption that PCBs aril
expected to be dernally absorbed from soil in a manner
similar to that of 2,3,7,8-TCDD because no studies of the
absorption of PCBs from soil were available (Appendix B),
An absorption factor of 5% of the applied dose was used to
evaluaff dermal absorption of PCBs from sediments, Poiger
and SCltlatter (1980) measured dermal absorption of 2,3,7,8-
TCDD fro* soil applied to rat skin to be 0.05 to 2,2% of the
applied dose (recalculated as 0.07 to 3% by EPA 1984*}>
Shu, et al. (1988) measured dermal absorption of TCDD in
soil applied to the skin of rats that was 1% of the applied
dose. Measurements of dermal absorption obtained from rat
skin are likely to overestimate human exposure, however.
The skin of the rat is highly permeable when compared to
human skin (Wester and Maibach 1980, EPA 1984). For

3-12
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example, the dermal absorption of hexachlorophene, a
compound structurally similar to PCBs, was reported to be
76% of the applied dose in rats (Chow, et al. 1978} and only
3% in humans (Feidmajm and Maibach 1970X *

The'deraaT:''''al)sorp'tlo^
appear to be plausibly estimated in the :risk assessmentil
EPA (1938) used a dermal absorption factor of 0.5% of the
applied dose for TCDD, an order of magnitude less than;the
value of 5% used in the risk assessment.
EPA RESPONSE 3.2.8

The EPA Baseline Risk Assessment for New Bedford Harbor
derived the toxicokinetic factors using the latest data
available on absorption factors for PCBs. For dermal
absorption, specifically, a value of 5% is the absorption
factor recommended in the EPA document titled "Development
of Advisory Levels for PCB Cleanup," dated May 1986. EPA
then adjusts the absorption factor to account for the fact
that the risk estimates are based on administered dose
rather than absorbed dose.
3.2.9 General Comments on Exposure Parameters

DCN #31, Page 3-16

SPA ignored its 'own guidelines in performing the exposure
assessment and instead manufactured potential risks by
linking together a series' of implausible worst-case exposure
assumptions,

EPA RESPONSE 3.2.9

The majority of comments pertaining to the RA deny the
validity of the assumptions used to quantify the potential
exposure contaminants incurred at this site. EPA generated
additional risk estimates based on the exposure parameters
recommended by the reviewers. These risk estimates support
the conclusions of the RA and establish the need for clean-
up at this site. It should be emphasized that EPA does not
recommend the use of all these exposure assumptions. These
reviewer risk assumptions include:

Direct Contact and Incidental Ingestion of Sediment - Area I

Exposure by older child
40 kg body weight
0.5 ma/cm - sediment deposition factor (versus 1.5
mg/cm )

3-13
-------
4,400 cm2 exposed surface area (total of 2.2 gm
contacted vs. 6.6 gm)
Exposure to 700 ppm and 378 ppm
10 exposures per year (versus 20)
50 mg sediment ingested/exposure
5% and 0.5% dermal TKF (versus 7%)
Use of 2.6 CPF (versus 7.7)

The risk estimates using the reviewers' risk assumptions are
presented in Tables 3-1 and 3-2 at the end of this section.

Exposure to 378 and 700 ppm PCBs results in incremental
carcinogenic risks ranging from 6x10"* to 8xlO"5. These risk
estimates are based on lower values than those recommended
by EPA. However, even under these conditions, the risk
estimates exceed the Massachusetts DEP total site
carcinogenic risk level of 1x10 . Since these risk
estimates are for a single route of exposure, they do not
represent the total site risk.

EPA also calculated risks associated with the ingestion of
biota based on revised exposure conditions. These revised
exposure conditions include:

exposure by older child
40 kg body weight
Ingestion of 6.5 grams fish/day
1 ppm PCB concentration in edible tissue
100% TKF
CPF of 2.6 and 7.7

These risk estimates are presented in Table 3-3 at the end
of this section. Risk estimates based on these exposure
conditions range from 6xlO"5 to 2xlO"4. These values exceed
the Massachusetts DEP total site carcinogenic risk level of
IxlO'5.

Combined risks from direct contact and ingestion of biota
for an older child range from 6.5xlO*5 (exposure to sediment
at 378 ppm PCB and ingestion of 6.5 grams fish/day at 1 ppm
PCB and a CPF of 2.6) to 2.6xl*4 [exposure to sediment at 700
ppm PCB and ingestion of 6.5 grams fish/day at 1 ppm PCB and
CPF of 7.7 (mg/kg-day)"1]. These risk estimates exceed
Massachusetts DEP risk level of IxlO*5 and fall within and
exceed EPA's target range of 10*4 to 10*7. These revised risk
estimates support the need for remediation at the Site.

Exposure and Risk Assessment is a developing science (SEAM,
1988). New information is being identified to assist in
providing more accurate estimates of risk at Superfund
sites. EPA intends to continue to revise its exposure and
3-14
-------
risk assessment methodology whenever scientific advances
indicate that doing so is appropriate.

3.3 TOXICITY OF PCBs

3.3.1 PCB Epidemioloqical Studies

DCN #26, Page 4

ATSDR should change its incohslstent discussion of the
clinical studies of capacitor workers. AS stated by Smith
and others, none of published occupational or epidemiologic
studies has demonstrated anvadverse health effects in
humans exposed to high levels of PCBs except for a
reversible."skin, condition;; jchloracne.

EPA RESPONSE 3.3.1

This comment is taken out of context from "Metabolic and
Health Consequences of Occupational Exposure to PCBs", Smith
et al. (1982). In the same paragraph where this sentence
appears, the authors discuss possible theories explaining
why, in 1982, there appeared to be few studies demonstrating
unequivocal and clinically observable adverse health effects
in humans exposed to PCBs. The authors state:

This inability to show convincingly an adverse effect on
human health from occupational exposure to PCBs may be
partially attributable to the often encountered confusion of
multiple chemical exposures in the workplace or in the
general environment, which either directly or in
combination, influence the health of exposed individuals.
It is necessary to recognize, however, that clinical and
epidemiological methods generally are not available that are
sufficiently sensitive and specific to allow a high degree
of confidence that, when no significant individual or group
effects have been found, an adverse health effect still has
not been overlooked.

When viewed within the context of the entire paragraph, the
statement is less categorical and precise, and does not
support the commenter's position at all. More recent
epidemiology studies suggest an increased risk of liver
cancer and/or leukemia from exposure to PCBs. Two of these
studies are occupational. All of them were published after
the Smith, et al. (1982) study. Those studies include:
Amano et al (1984), Kuratsume (1989), and Bertazzi, et al.,
(1987) and are discussed below.

For polychlorinated biphenyls, the epidemiologic evidence is
currently viewed by EPA's Office of Health Exposure

3-15
-------
Assessment (OHEA) as "inadequate" according to EPA criteria.
However, OHEA has supplemented this conclusion with a
comment stating that the available date are "suggestive".
The International Agency for Research on Cancer (IARC)
classified the evidence as "limited" based on the studies by
Brown (1987) and Bertazzi, et al. (1987). Yet, a third
published study by Amano, et al. (1984), and an unpublished
follow-up of that study by Kuratsume (1986) also
demonstrated a statistically significant excess risk of
liver cancer in males as well as an excess risk of liver
cancer in females who accidentally consumed rice oil
contaminated with PCBs some seventeen years earlier in
Japan. This rice oil was also contaminated with
polychlorinated or monochlorinated dibenzofurans (PCDFs or
CDFs) in the ratio of approximately 200 molecules of PCB to
1 molecule of PCDF. However, the portion of risk
attributable to the furans separately, or to the PCBs
separately, or to both in combination cannot be determined.

The conclusions of Bertazzi, et al., are noteworthy.
"Interpretation of the results is limited by the small
number of deaths; however, the point of interest is the
consistency of these results with previous experimental and
epidemiologic studies, which indicated the GI tract and
lymphatic and hemopoietic tissue as the most probable target
sites of the PCB carcinogenic activity."

Brown (1987) concludes "A statistically significant excess
in deaths was observed in the disease category that includes
cancer of the liver (primary and unspecified), gall bladder,
and biliary tract (5 obs. vs. 1.9 exp.; Page 05)....Due to
the small number of deaths and the variability of specific
cause of death within this category, it remains difficult to
interpret these findings in regard to PCB exposure." Brown
notes that no deaths occurred prior to 15 years from first
employment and that the deceased began working during a time
period when levels of exposure were probably the highest and
when the higher chlorinated PCB mixtures were being used.
Clearly, Brown views the question of how much exposure as an
uncertainty. Neither OHEA nor Brown make the case that
there is a clear-cut and definite conclusion from this data.

In both the Brown and Bertazzi studies as well as the
additional cited references (Zack and Musch, 1979;
Gustavsson, et al., 1987), the authors make it clear that
because of the small sizes of the cohorts and small number
of deaths observed, it was impossible to assess either
latent effects or a possible dose-response relationship.

The ultimate conclusion reached by EPA epidemiologists from
an evaluation of the available epidemiologic evidence is
that there is a suggestion of significantly increased risk

3-16
-------
of cancer of the liver and biliary tract in persons who are
exposed to PCBs contaminated with PCDFs across several human
cohort studies. From an exposure point of view, it is not
clear which group of isomers or parent compounds might be
responsible for the excess risk. Because of these
limitations and those alluded to by the authors, OHEA has
concluded that the sum total of the evidence does not
measure up to the criteria for either "sufficient" or
"limited" positive evidence. However, the consistently
reported elevated risk of liver cancer in three studies
cannot be dismissed.

It should be noted that the OHEA conclusion that PCBs pose a
"probable" hazard to humans does not hinge on the
interpretation of the human data alone. Rather, it is
supported by experimental data as well. This is consistent
with the scheme for classifying carcinogens in the published
EPA guidelines.

Although not specifically discussed in the PRP comments, the
issue of whether PCBs can cause reproductive and/or
developmental adverse effects in animals is addressed in
this paragraph. The authors of one report summarized
epidemiological evidence on health effects other than cancer
that may be associated with exposure to PCBs. While EPA
agrees that the human data base is limited, the laboratory
animal data base supports the conclusion that PCBs are
reproductive and developmental toxicants. Exposure in
animals at levels of 0.01-1 mg/kg/day has been associated
with alterations in reproductive and developmental end
points, depending on species of Aroclor, animal species,
exposure period and route, and end points examined.
Reported effects include: reduced litter size and
viability, and altered growth. Slightly higher levels were
associated with reduced thyroid function.
3.3.2 DIFFERENCES IN POTENCY AMONG DIFFERENT PCB MIXTURES

DCN #8, Page 1

The carcinogenicity potency factor used by EPA already has
many conservative assumptions built in some of which are
listed?belowt
•> s#xw .w Jw •. -.^x-w •

1. Benign and malignant tumors are counted as cancer.
2. High to low dose extrapolation is done using the most
conservative model available*
3» Surface area instead of weight is used for species to
species conversion*
4* No threshold dose is used although there is ample
evidence that PCBs act by an epigenetic mechanism.

3-17
-------
5. All PCBs mixtures are treated as though they are
Aroclor 1260. Studies have shown that lower
chlorinated PCBs are less potent or do not cause cancer
at the doses tested.

This review is confined to the PCB section in this
toxicological evaluation. The authors have given a very
unbalanced view of the literature* In many instances, only
the studies reporting a PCB-related finding have been
included without presenting other studies that hav« looked
for but not found such Affects. Specific criticisms are
given JLn Jth*, f ollowing paragraphs *

DCN #15, Page 5-5

In summary, the Terra evaluation concludes that there is no
evidence of carcinogenicity of 42% chlorine PCB mixtures
(Aroclor 1016, Aroclor 1242) in animals or humans. The
report further concludes that there is no evidence for the
carcinogenicity of 54% chlorine PCB mixtures (Aroclor 1254)
is equivocal and of questionable relevance to man* Although
the report concludes that there is evidence for the
carcinogenicity of 60% chlorine PCB mixtures (Aroclor 1260)
in animals, several aspects of the animal bioassay results
indicate that these studies also have limited relevance to
humans. The Terra report concludes that there is inadequate
evidence to show an association between PCB exposure and
cancer in humans (Terra, 1989).
--.:•:-...,..-.•.-• . . . .-.•.vXv.v.v.'^-X'Xv.-x-;'.-:-:.^*..- .,;-.•,..:•...•.:$•.-..• ..-• -.-.^...'..-.. • .-.-.,-.. ....•.-.-.*.... • ,

DCN #31, Page 3-3

The risk assessment characterized concentrations of PCB
mixtures in sediments from New Bedford Harbor as total PCBs
and improperly evaluated their risk as though all the PCBs
were Aroclor 1260. Characterizing all PCBs as one entity is
misleading because the PCB mixtures in the sediments vary in
composition (i.e. r extent of chlorination) and the toxicity
of different commercial PCB mixtures varies widely (see
Section 4). ' •-•—•--•••••

DCN 131, Page 3-31

This model has been re-evaluated at the request of EPA by
the person who devised it, and among the conclusions of this
two-year study (Allen, et al.t 1987) are that the EPA Cancer
Potency factor of 7.7 mg/Jcg/day should be closer to 0.61
»9/<*g/dayr &nd that EPAfs use of the former CPF, in
combination with other scientifically invalid methodologies,
i.e., surface area conversations between species, overstate
risk 12 fold. Use of the 0.61 mg/kg/day, and that EFtA*s use
of the former CPF, in combination with other scientifically
3-18
-------
invalid methodologies, i.e., surface area conversions
between species, overstate risk 12 fold.

DCN #31, Page 3-34

EPA (1989) states; "Mthbugh It; Is known :that PCB congeners
vary greatly as to their potency biological effects, for
purposes of . ..carcinogenicity assessment Aroclor 1260 is
intended to be representative of all PCB mixtures »w There
is no scientific support for this generalization,

DCN #31, Page 3-44

A7::caricer 7 'potency; ::'valueTfor:"Arot:lor 1260 was used to
characterize potential risks posed by exposure to sediments.
As discussed earlier in Section 2»2, the congener analysis
of PCB residues in seafood that was presented to justify the
use of the potency factor for Aroclor 1260 is not applicable
to sediments. The sediment residues have not been subjected
to the same pharmacokinetic influences as the seafood
residues. The extensive use of lower chlorinated Aroclprs
in the New Bedford Manufacturing community makes the
presence of less-chlorinated residues even more Iikely7''njjs'i
of a cancer potency for Aroclor 1260 to characterize upper
bound excess cancer risks posed by sediments is
inappropriate/ coupled with incorrect and: inflated estimates
of cancer potency leading to exaggerated estimates of cancer
values-, than likely- to be. .true).
EPA RESPONSE 3.3.2

The currently available cancer bioassay data on five
commercial PCBs, i.e., Aroclor 1260, Kanechlor 500, Aroclor
1254, Clophen A-60 and Clophen A-30, while providing
positive carcinogenic evidence in experimental animals do
not help -to resolve the uncertainty about the mixtures.
These five PCB tested mixtures contain variable quantities
of various PCB congeners, including both lower and higher
chlorinated biphenyls. Most of the positive bioassays are
representative of higher chlorination mixtures with the
exception of Clophen 30. The chlorination composition of
Clophen A-30 (chlorine content of 41.3%) contains a higher
percentage of lower chlorinated biphenyl. While one could
observe that the higher chlorinated biphenyl mixtures
induced carcinogenicity and Clophen A-30 which contains a
higher percentage of lower chlorinated congeners also
induced a carcinogenic response, any qualitative inference
about the potential for human carcinogenic activity based
solely on these observations is weak.
4
OHEA's risk assessment view is that, as a default choice,
all PCB mixtures have a slope factor no higher than or

3-19
-------
equivalent to Aroclor 1260. The upper bound slope factor
for Aroclor 1260 is 7.7 and is based on the rat study by
NorbacJc and Weltman.

OHEA, and more recently the EPA Risk Assessment Forum, has
been actively investigating the technical feasibility of
developing a congener-specific approach, perhaps using a
toxic equivalency factor (TEF) basis, for assessing cancer
and non-cancer risks from exposure to PCBs. As a
feasibility study has not yet been released, it is not
likely that such an endeavor will provide a completed TEF
approach in the near future.

3.3.3 INITIATION VERSUS PROMOTION

DCN #38, Page 11-35

Many animal studies report both a cancer promoting ability
of PCBs and a cancer inhibiting ability.

EPA RESPONSE 3.3.3

The EPA's current guidance that addresses mechanisms of
carcinogenesis is found in the Federal Register, Vol. 51
(33992-34003). "Agents that are positive in long-term
animal experiments and also show evidence of promoting or
cocarcinogenic activity in specialized tests should be
considered as complete carcinogens unless there is evidence
to the contrary because it is difficult to determine whether
an agent is only a promoting or cocarcinogenic agent.
Agents that show positive results in special tests for
initiation, promotion, or cocarcinogenicity and no
indication of tumor response in well-conducted and well-
designed long-term animal studies should be dealt with on an
individual basis.1*

In many laboratory animal experiments, exposure to PCBs have
resulted in carcinogenesis. However, in other animal
experiments, some tumor inhibition was noted. This tumor
inhibition is likely to be related to enzyme inductions.
The enzymes induced range from those that are involved in
metabolis of PCBs themselves to others that have been
implicated as activators and inactivators of other
procarcinogens or carcinogens, respectively (cytochrome P-
450 and P-448 associated monooxygenase system). The mixed
nature of the PCBs would be reflected in mixed enzyme
induction, some of which would be capable of exerting the
inhibitory effect and some of which would exert the
promoting effect. The tumor inhibiting ability of PCBs may
be dose and congener related, but it has not consistently
been observed, even in relatively similar experimental
studies.

3-20
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3.4 RISK EVALUATION

DCN #31, Page 3-37
Th¥vrlskrassi8s'iraient'"caIcialatiBaT''a:''hazard index'tb:'"estimate
the likelihood of adverse noncarcinogenic effects by adding
together, the relative risks associated with lead, copper,
cadmium, and PCBs to derive a total potential site risk.
The statement is made on page 4-4 that hazard index values
are calculated for exposure to the mixture "because these;
compounds have1 been shown to exert similar toxic effects1*,
Similar statements are made oh pages 4-7 and 4-26. Review
of the bases for the criteria from which each of the
toxicity values used to calculate the hazard indices were
derived shows that the end points of toxicity of, concern are
very diverse indeed and in no way justify combination*

DCN #31, Page 3-38

Thus, the'risk a8isWs'iSme1if^faiTB^ta"'f6Ilow' EPA guidance for
performing, risk assessments of noncancer effects by
combining dissimilar end points of toxicity, substantially
overestimating noncancer risto ~

EPA RESPONSE 3.4

The risk estimates generated in the Baseline RA were derived
according to guidance by EPA and Massachusetts Department of
Environmental Protection. Chronic Daily Intake/Reference
Dose (CDI/RfD) values were calculated separately for each
compound in addition to being summed for each exposure
scenario to provide a total Hazard Index (HI) value. The
risk assessment states the uncertainties associated with
developing these HI values and interpreted these results
accordingly. The total CDI/RfD value was used to support
conclusions regarding the potential adverse effects
associated with exposure to a single contaminant. Potential
risks were first evaluated using the single-contaminant
value. If this value exceeded 1, further evaluation was
performed using the total HI.

The quantitative risk estimates were evaluated against the
criteria set forth in the SPHEM and DEP's Contingency Plan.
The State of Massachusetts has clearly defined values for
determining the need for remediation of an uncontrolled
hazardous waste site. These are total site incremental
risks of 10"5 and noncarcinogenic HI of 0.2. These values,
in addition to EPA's target incremental carcinogenic range
of 10"4 to 10"7 and noncarcinogenic HI=1, were used to
identify contaminants and/or routes of exposure which were
associated with public health risks.

3-21
-------
3.5 GREATER NEW yflgpfQRD HEALTH EPPEOTS STUDY

DCN #31, Page 3-45

other evidence of the risk assessment's excessively
overestimated risk comes from the Greater New Bedford Health
Effects Study (GNBHES) , which was conducted as a result of
the concern about PCS contamination in New Bedford Harbor to
determine the prevalence of elevated serum PCB levels in the
Greater New Bedford population. CDC has estimated that 99%
of unexposed persons in the U.S. have serum PCB levels less
than 30 ppb; for the GNBHES, levels above 30 ppb were
assumed to represent elevated levels. Of the 840
individuals examined, only 11 (1.3%) had levels above 30
ppb. On the basis of these results, a second study was
conducted to evaluate the serum PCB levels of residents who
were thought to be at high risk of exposure due to their
relatively high levels of ingestion of seafood from
;: areas-.'' ' '" "'"" ' '" ' ' " ...... " """ " " ' ' """ " " " " "" " ' ' """"'"" -•••••••—-

DCN 115, Page 5-3

Although this epidemiological study concluded that Greater
New Bedford area residents do not have significant
environmental exposure from PCBs, EPA undertook a baseline
risk assessment (Ebasco, 1989) which involved the use of
theoretical exposure . and toxicol og ical model a . v

DCN #6, Page 22

The GNBHES found little evidence of excessive exposure to
PCBs (as evidenced by elevated PCB blood levels) and the
population appeared no different from other US populations
with much less likelihood of PCB exposure.
EPA RESPONSE 3.5

The exposure scenarios developed in the Risk Assessment are
not intended to predict the actual number of individuals
exposed to PCBs. The scenarios are intended to reflect the
possible exposures received by hypothetical individuals in
order to assess risks posed by the Site. The Greater New
Bedford Health Effects Study (GNBHES) had an entirely
different purpose. The primary focus of the GNBHES was to
determine the prevalence of serum PCB levels among residents
of the Greater New Bedford area. However, the GNBHES does.
show that individuals who eat locally caught seafood have
elevated PCB serum levels. Thus, contrary to the assertions
in the comments, the exposure scenarios appear to be valid.
The following is a summary of the GNBHES.

3-22
-------
The prevalence rates presented in the final report of the
GNBHES (i.e., 1.3% had serum PCS levels greater than 30 ppb
and 2.7% had serum PCB levels greater than 20 ppb)
demonstrate that the general population has not suffered
unusual exposure simply as a result of living in close
proximity to an area that has suffered serious environmental
contamination. These rates do not imply what the health
effects of consumption of locally caught contaminated
seafood are on the general population (i.e., on serum PCB
levels).

Additionally, the Massachusetts Department of Public Health
(DPH) conducted an enrichment study (ES) to identify
individuals who were likely to be exposed to PCBs via
consumption of contaminated seafood or occupational exposure
and hence to identify an exposed population necessary for
proceeding to Phase II of the Health Effects Study. While
eligibility criteria included both routes of exposure, the
majority of these individuals were selected on the basis of
seafood eating habits. The primary objective of the ES was
to identify an exposed population. However, it is possible
through further evaluation of the data, the role that
contaminated seafood consumption plays with respect to serum
PCB level may be delineated.

To accurately assess the contribution of seafood consumption
solely, it is necessary to eliminate those individuals
reporting occupational exposure to PCBs in both the
enrichment and prevalence samples. To address concerns that
age is responsible for any difference in serum PCB level
between the two samples, it is equally important to
eliminate those prevalence participants who do not meet the
age criteria for inclusion in the enrichment study.

Listed below are the major observations from this study
regarding the relationship between eating locally caught
contaminated seafood and serum PCB levels. (The figures and
tables referred to in this response are presented at the end
of this Section of the Responsiveness Summary.)

1. Those individuals who more likely ate contaminated
seafood (enrichment sample) presented higher serum PCB
levels than individuals who were less likely to eat
contaminated seafood (prevalence sample). These
results are shown in Table 3.4.

2. The relationship described above in #1 was consistently
observed for each age group represented. These results
are shown in Figure 3.1.
3-23
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3. Additionally, this pattern remained when the
individuals with possible occupational exposure to PCBs
were removed from the analysis. These results are
shown in Figure 3.2.

4. The serum PCB level in those most likely to have eaten
contaminated seafood (enrichment sample) did not vary
greatly as age increased. Serum PCB levels, however,
did vary somewhat as age increased for those who were
less likely to have eaten locally caught contaminated
seafood (prevalence sample). These results are shown
in Figures 3.2 and 3.3.

5. When frequency of seafood consumption was evaluated,
the serum PCB level was consistently higher in those
who were more likely to have eaten locally caught
contaminated seafood (enrichment sample) than those who
likely did not eat as much (prevalence sample). This
observation may be due to the earlier observation that
the enrichment sample subjects usually had higher serum
PCB levels than the prevalence sample subjects. Most
importantly, though, is that for both the prevalence
and enrichment sample subjects as seafood consumption
increased, so did serum PCB levels. These (serum PCB)
results are shown in Figure 3.4.

6. Analyses of frequency of consumption indicated that the
serum PCB levels did not differ significantly with
' level of seafood consumption for the enrichme'nt sample
(the sample size is small for each consumption level).
However, statistically significant results were
observed in the prevalence sample. This analysis
indicates that those who eat seafood once a week or
twice a week had significantly higher serum PCB levels
than those who ate seafood less than once a week or
less than once a month. These results are shown in
Table 3.5.

7. Further analyses on frequency of consumption suggest
that this observation may be partly due to the effect
of age, but not to the effect of occupational exposure.
In other words, an individual's serum PCB level may be
higher in individuals who ate more seafood but only in
certain age groups. Table 3.6 shows that the
differences in serum PCB level are no longer
statistically significant when age is taken into
consideration but that there are statistically
significant differences between age groups. However,
this explanation does not dismiss the likelihood that a
relationship between consumption of locally caught
contaminated seafood and serum PCB levels exists.
Rather, this observation supports such a relationship,

3-24
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particularly if the serum PCB level is higher among
those who consume seafood at a greater-frequency and if
the serum PCB level increases as age increases. This
result would imply that because of the higher frequency
of consumption as age increases, serum PCB level may
increase as a result of bioaccumulation. Figure 3.4
illustrates the relationship between serum PCB level
and age, and frequency of consumption for the
prevalence sample observed in this study. In almost
all age groups, the serum PCB level is higher for those
with a greater frequency of consumption. Furthermore,
the general trend is for serum PCB levels to increase
as age increases.

8. Figure 3.5 presents the prevalence sample serum PCB
levels for those who consumed locally caught
contaminated seafood versus general seafood type
according to age. While the numbers are small for each
age group, the same trend observed in the enrichment
sample can be seen among those who ate locally caught
contaminated seafood among the prevalence sample.
Serum PCB levels are higher in every age .group except
the 18-24 group for the local seafood consumers
compared to the general seafood consumers. The
observations that:

a. Serum PCB levels increased with age for the
consumers of locally caught contaminated seafood
(local group) in the prevalence sample, '

b. Serum PCB levels-were higher in those with a
higher frequency of seafood consumption for almost
every age group, and

c. Serum PCB levels were higher for each age group
among those more likely to have consumed locally
caught contaminated seafood
3.6 ECOLOGICAL RISK

3.6.1 ENVIRONMENTAL RISK ASSESSMENT

DCN #5, Page 2-3

The first paragraph of this section narrows the risk
assessment merely to PCBs, ignoring the documented
occurrence in the Hot Spot area of extremely high
concentrations of toxic heavy metals (Cadmium, Lead, Zinc,
Nickel, Chromium, Copper, and Arsenic), the mobilization of
which is certain under the favored remedial alternatives.
Moreover, the risk assessment fails to deal with toxic

3-25
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organics such as PAHs, which also reside in the sediments
that are scheduled to be disturbed.

DCN #5, Page 4

The first paragraph of this section refers to toxictty
experiments conducted by Hansen in which amphipods and
sheepshead minnows were exposed to sediment from areas I and
IX of the harbor. Note that the toxicities reported were
the result of all of the materials In the sediments, not
specifically to PCBs. The use of this information does not
seem appropriate to a risk assessment that Is confined
(3*2*1} to PCBs. Moreover, the species of amphipod
(Ampeliaca abdital used by Hansen in his experiments was not
found by the U.S. Army Corps of Engineers in its benthic
study of NeW;^B«dford::Harbor* "'*"""' ,,,,.,,,,,,,,,,.,,,.,,,,..,...

DCN #5, Page 10

The statement in paragraph 2, "Due to the extreme
contamination present in Hot Spot surface sediment, benthic
and demersal organisms are effectively precluded from living
in the area", Is clearly wrong. As we noted above, the
USAGE benthic study shoved the Hot Spot region (their
station 1) to have one of the highest densities of living
organisms In the entire harbor. With; this objection In
place, the following sentence ("This loss of habitat is
potentially significant..."} in the same paragraph is
meaningless.- There has been no loss of habitat duetto
contamination of Rot Spot sediments. The first sentence of
the second paragraph ("Ecological risks due to transport of
PCBs from the Hot, Spot sediment are a function (sic}, of the
amount of sediment exposed and the extent of contamination
in the sediment1*} is a sweepingly simplistic one. Heavy
metals are probably more toxic and present greater threats
. to.;the. environment than PCBs. " "'

3.6.1 EPA RESPONSE

The Hot Spot area of the Estuary stands out from other site
areas because the area is grossly contaminated with PCBs.
The level of heavy metal contamination in the Hot Spot is
similar to other site areas. EPA recognizes that certain
heavy metals can be acutely toxic to aquatic organisms,
however, the potential for adverse effects to biota from
chronic PCB exposure at this level is high. EPA is
currently completing a baseline environmental risk
assessment for the site that examines the potential baseline
risks to biota from exposure to heavy metals.
• •
The work completed by EPA (Hansen, 1986) demonstrated a
correlation between differing PCB levels across the site and

3-26
-------
toxicity. While the toxicity is attributed to the sediments
and not necessarily the PCBs, the correlation existed
between differing PCB levels not to changes in other
contaminated concentrations.

The results of the benthic survey demonstrated that at
sampling station 1 the species diversification was small and
the area contained organisms that typically inhabit
environmentally stressed sediments.

3.6.2 BENTHIC SURVEY

DCN #5, Page 6

The sajnpiIng methodology used in the col lection:""of 7Benthic
invertebrates appears to be so seriously flawed that the
subsequent analysis and conclusions drawn are probably
incorrect. The methods used here surely grossly
underestimate the number of organisms found in the sediments
above the Coggeshall Street bridge and probably also under
estimat^ species found there as well*

DCN #5, Page 9
Irifaurial communities are responsive tb''p'hyisicar''vand''vch'ieiniical
features of their environments such as sediment type and
^structure ....and -.salihiitief^in'ways that have not been
evaluated-'. here>i-t;;;;indjB^::>Miiriity was "not even measured in
£his|:;itu^;^ that taxonomic
identifications maylhaveb For example Havelockia
'X reported:;: hereof is "'ai-'rare . deep water holothuran (10-
1200 m) and has never been reported before from Buzzards Bay
or adjacent waters. It was probably confused with
Sclerodactyla briareus (** Thvone) . Odostomia seminuda does
not seem to have been recognized as an epizooite living
commonly with Crepidula „
EPA RESPONSE 3.6.2

EPA used procedures described in "Standard Methods" (1985)
and "Soke and Rohlf" (1981) in conducting the benthic
surveys. EPA believes these procedures are sound
methodology. While sample size may not have been at optimum
levels, the unequal sample size was corrected by using
multi-regression analysis techniques.

EPA's studies show the Estuary-sediment^to be a sandy
organic silt that generally increases in silt and organic
content in a northerly direction. EPA has characterized the
Acushnet River Estuary as a "weak" estuary. This

3-27
-------
characterization is based on EPA^studies that report
salinity measurements ranging frfcm approximately 29 to 32
parts per thousand with weak vertical stratification.

EPA believes the Havelockia scabra located during this
benthic survey may have been transported to this location by
a number of possible mechanisms (e.g., falling off fishing
gear, ocean currents, self locomotion, etc.)* EPA believes
the identification of the Odostomia seminuda to be correct
based on the habitat and potential food sources (i.e.,
several species of bivalves) in the area.
###
Section 3 References
Amano, et al., 1984. "Statistical Observations About the
Causes of the Death of Patients with Oil Poisoning."

American Public Health Association, 1985. "Standard Methods
for the Examination of Water and Wastewater," 16th ed.
Washington, D.C.

Bertazzi, et al., 1987. "Cancer Mortality of Capacitor
Manufacturing Workers."

Brown, et al., 1987. "Mortality of Workers Exposed to PCBs
- An Update.1*

B.C. Jordan/Ebasco, 1987. "Environmental Evaluation -
Selection of Additional Contaminants for Inclusion in the
Risk Assessment and Feasibility Study."

E.C. Jordan/Ebasco, 1987. "Draft Final Hot Spot Feasibility
Study, New Bedford."

Gustavsson, et al., 1986. "Short Term Mortality and Cancer
Incidence in Capacitor Manufacturing Workers Exposed to
PCBs."

Hansen, 1986. "Preliminary Data Report, New Bedford Harbor
Project," unpublished, U.S. EPA Environmental Research
Laboratory, Narragansett, RI.

Kuratsume, 1988. "A Cohort Study on Mortality of Yusho
Patients: A Preliminary Report."

Massachusetts Department of Public Health, 1987. "The
Greater New Bedford Health Effects Study, 1984-1987."
3-28
-------
Norback and Weltman, 1985-. "PCB Induction of Hepatocellular
Carcinoma in the Sprague-Bawley Rat."

Smith, et al., 1982. "Metabolic and Health Consequences of
Occupational Exposure to PCBs.11

Sokal, R.R. and F.J. Rohlf, 1981. "Biometry: The Principles
and Practice of Statistics in Biological Research," 2nd ed.
W.H. Freemen and Company, New York.

Zach and Musch, 1979. "A Retrospective Mortality Study of
PCB Manufacturing Workers."
3-29
-------
TABLE 3-1
pcb-378
Mew Bedford Harbor
Direct Contact Kith and/or Ingest ion of Soil or Sediment
Carcinogenic Effects
This table calculates estimated body doses and incremental carcinogenic risks.

The aquations to calculate body dose level and increeiental carcinogenic risks are:

poil
Body Dose > Concentration • ((Amount Contacted x Dermal TK Factor) » (Amount Ingested x Ingestion TK Factor)] *
(mg/kg/day) (ug/g) (g/event) (g/event)
u»
o
1
No. Events
Mo. of years
exposed
1 yr
Body Weight
(kg)
years
70 years
1000 ug
565 days 1000 ug
Incremental Risk * Body Dose x CAG Potency Factor
mg/kg/day (mg/kg/day)~-1
1
| Compound
1

IPCBS
1
IPCBS
1
IPCBS
1
IPCBS
1
1
Concentration
(ug/g)

378

Amount of
Soil Contacted
(g/event)
..............
2.2

2.2

Amount of
Soil Ingested
(g/event)

II 05

0.05

O.OS

0.05

Dermal TK
Factor

0.005

0.05

0.005

Ingestion
TK Factor

1.00

Body
Weight
(kg)

> 40

No. of
Events
per year

No. of Years
Exposed

10.0

Ingestion
Body Dose
(mg/kg/day)

1. BSE -06

1.85E-06

1. BSE -06

Direct Contact
Body Dose
(mg/kg/day)

4.07E-07

4.07E-06

4.07E-07

| CAG Potency
| Factor
[<»9/kg/day)' 1

2.60E»00

7.70E»00

7.70E«00

1
{Incremental
Risk

S.87E-06

1.S4E OS

4.56E 05

1.74E-OS

-------
TABLE 3-2
pcb-700
New Bedford Harbor
Direct Contact Mith and/or Ingest ion of Soil or Sediment
Carcinogenic Effect*
this table calculates estimated body doses and incremental carcinogenic risks.

The equations to calculate body dose level and incremental carcinogenic risks are:

Soil
Body Dose » Concentration x ((Amount Contacted x Dermal TK Factor) » (Amount Ingested x Ingest ion TK factor)] x
(mg/kg/day) (ug/g) (g/event) (g/event)
1
1 yr
Body Weight
(kg)
No. of years
No. Events exposed lag
x x x
years 70 years 1000 ug 365 days
1000 ug
Incremental Risk * Body Dose X CAG Potency Factor
•g/kg/day (mg/kg/day)A-1
1
(Compound
1.

IPCBS
1
IPCBS
1
IPCBS
1
IPCBS
1
1
Concentration
(ug/g)

700.0000

700.0000
Amount of
Soil Contacted
(g/event)

2.2

2.2
Amount of
Soil Ingested
(g/event)

0.05

0.05
Dermal TK
Factor

0.005

0.05

0.005
Ingest ion
TK Factor

1.00

1.00
Body
Weight
(kg)

40
No. of
Events
per year

10
No. of Years
Exposed

10.0

10.0
Ingest ion
Body Dose
(mg/kg/day)

S.42E-06

3.42E-06

3.42E-06
'
Direct Contact
Body Dose
(mg/kg/day)

7.53E-07

7.53E-06

7.53E-07
CAG Potency
Factor
(mg/kg/dayr-1

Z.60E+00

2.60E+00

7.70E»00

7.70E»00
.
Incremental
Risk

1.09E-05

2. BSE 05

8.44E 05

3.22E 05
-------
Incremental Carcinogenic Risks Associated with Ingest ion of Fish
TABLE 3-3
1
|CcMfxx«id
1

1
|PC8s
1
IPCBS
1
|PCBs
1
IPCBS
1
1
'
i
u>
K)

Concentration
(•a/kg)

1.00

Awxnt of Fish
ComtMd
(9/fish Mai)

227

6.5

t aeals
year

565

i years
exposed

Fraction
Absorbed
(TKF)

Body
Weight
(kg)

CAC Potency
EstiMte
(•g/kg/day)-1

2.6

7.7

2.6

7.7

Carcinogenic
• isk
EstiMte

6.95E-OS

2.06E 04

6.04E-OS

1.796 04

-------
TABLE 3.4
Mean PCB levels by population sampled
Prevalence Enrichment
Sample Sample
Mean 5.8 13.3
3-33
-------
TABLE 3.5
Serum PCB levels by Frequency of Seafood Consumption
for Prevalence Sample
Frequency
of
Consumption
Mean
PCB
Level
Least
Squares
Means
F-Value
Probability
-------
TABLE 3.6
PCB Level by Frequency of Seafood Consumption
for Prevalence Sample -
Age and Occupational Exposure Controlled
Mean Least
Frequency of PCB Squares
Consumption Level Means F-Value Probability

-------
FIGURE 3.1
Comparison of Prevalance and Enrichment
PCB Levels by Age Groups
Level
18-24 25-34
35-44 45-49 50-54
Ages
55-59 60-64
Prev.
Enrich.
-------
RE 3.2
U)
Comparison of Prevalance and Enrichment
PCB Levels with Occupationally
Exposed Subjects Removed
14

8
PCB Level
4

18-24 25-34 35-44 45-49 50-54 55-59 60-64
Ages
Prev.
Enrich.
-------
FIGURE 3.3
Distribution of Mean PCB Level
by Age Groups for Enrichment*
20
15
10
PCB Level
CJ
0»
35-44
45-49
50-54
Ages

Enrichment
55-59
60-64
Local Seafood Consumption with
Occupational Exposure Removed
-------
PI
3.4
PCB Level by Age and Frequency of
Seafood Consumption *
PCB Level
18-24 25-34 35-44
45-49
Ages
50-54 55-59
1-2/week
<1/week - <1/month
60-64
Prevalance Sample with Occupational
Exposure Removed
-------
FIGURE 3.5
*-
o
COMPARISON OF LOCAL AND GENERAL SEAFOOD
CONSUMPTION FOR PREVALENCE SAMPLE
MEAN PCB LEVEL(ppb)
18-24
25-34 35-44 45-54
AGE GROUPS
^H Local
*

1 consumers of locally caught seafood
2 consumers of general but not locally
caught seafood
General

n-74
55-64
-------
SKCTTQN 4.0 - FATE AND TRANSPORT

4.1 MIGRATION OF PCRS FROM HOT SPOT

DCN #1, Page 6, Paragraph 1

.^'.'Tixefcoritractdr concedes that site specific data are
unavailable for; the hot spot area, and as a result, it is
not possible to determine the.relative contribution of
on present or future PCB distribution
are even occurring. In spite of
Agency is proceeding as if it knows what
is happening to PCBs from the hot spot* There is a total
absence of val-id scientific research with, respect to
migration from the hot spot and what, if any, impacts- it may
have on the balance of the site. ,Ho.action, should be taken
with respect to the hot spot until an overall remedial plan
has: beenvjaelected..:

DCN #2, Page 7, Comment #4

Throu'g'hou'trrtEe::'' repdrt;:"there;V;:'is ran-:''as'sumption% that the hot
spot is a principal source for contamination for the
estuary. This assumption is ultimately used to justify
treatment of the hot spot sediments. No proof of any kind,
however, is offered to show how the PCBs in the hot spot or
in--'any other:,sediments.,.-in.,the/'upp^er>estuary f«nter^the^water
colui|n| '•"™~---"~"-'-~-*-j*—'-'"m'™- •-" ~,»,.v, - ~

OCN 12, Page 8, Comment #5

There is an inherent assumption that reduction in total PCB
mass (independent of location) leads to.an equivalent
reduction in the long term transport of PCBs for the site
and hence to reduce risk. From an environmental risk
perspective, however, there is an important difference
between PCBs which are potentially mobile (in the near
surface sediments) and those that have severely limited
mobility (deeper in the sediments). From a risk assessment
viewpoint removal of mobile, near surface sedimentst
inoTeplaidiht'or their total mass f is more important than the
total,jsa£s, of PCBs removed. The use of total PCBs removed as
the oiip^m^a'sure of acceptability of a remedial action
technjS^^is^ simplist icr

DCN #2, Page 8, Comment #6

The report is devoid of any real analysis on how the
proposed remediation measures will impact the environment.
No calculations or analyses are given as to the effects of
the removal of the hot spot on the transport of PCBs out of

4-1
-------
the upper estuary, impacts to the ecosystem or public health
risks. The authors rely solely on reduction in PCS mass as
the measure of impact reduction. On the other hand there is
extensive analysis of the costs associated with each
remedial action measure„ ^

DON 13, Page 2

"Since the hot spot area contains close to half the total
ma«» of PCB» in the estuary, this area will continue to act
as a source of PCB contamination to the remainder to the
estuary and the lower harbor and bay." This statement is
misleading. It implies, without reference to the literature
or to supporting analysis, that reduction of total PCB mass
leads to a corresponding reduction in PCBs released into the
water column. This basic assumption, which provides the
basis for the whole hot spot feasibility study, is
erroneous. Isolation and destruction of PCBs that are
potentially mobile, (i.e. in the near surface sediments)
independent of their total mass, are more important the
total mass removed*
EPA RESPONSE 4.1

EPA has conducted extensive studies of the hydrodynamics,
sediments, and biota for New Bedford Harbor Site including
field, laboratory and model studies. These studies
demonstrate that PCBs are moving both within the and away
from the Site. EPA did not perform PCB sediment flux
modeling for the Hot Spot Area to estimate its contribution
of PCBs to the water column. However, EPA believes that
this concentrated mass of PCBs continues to release PCBs to
the water column. This hypothesis is supported by the
direct correlation between the distribution of contaminated
sediment and the observed water column concentrations. This
correlation is illustrated by the extremely high water
column concentrations of PCBs in the vicinity of the Hot
Spot.

Further evidence of the important role of the Hot Spot is
apparent in the flux modeling conducted by PRPs. This
modeling estimates at least 30% of the total PCB flux is
derived from the areas of contamination in excess of 4,000
ppm PCBs (i.e., the Hot Spot). Figure 4-1 at the end of
this section illustrates this information.

Other information presented by the PRPs during the public
comment period for the Hot Spot, also supports EPA's
hypothesis that PCB contamination is being spread throughout
areas of the Estuary and Lower Harbor/Bay by movement or

4-2
-------
flux out of the bed sediments. In the PRPs' analysis of
their thin layer sampling program (Thibodeaux 1989c), the
following observation, referring to a sediment sample ("Site
DR") taken in the estuary midway between the Hot Spot and
the Coggeshall Street bridge, is made. "Another curious
aspect of Site DR is that it appears to still be receiving
PCBs into the sediment... This source is very likely those
sediment areas in the upper estuary containing higher levels
of PCB contamination than the DR site."

EPA has conducted air and water monitoring programs to
document whether PCBs are moving away from the Site. The
results of the air programs are discussed in Section 4.3 of
this Responsiveness Summary. For transport within the water
column, several monitoring programs conducted by EPA and the
PRPs have documented a net seaward flux of PCBs from the
southern end of the estuary at the Coggeshall Street Bridge
(EPA, 1983, Teeter, 1988 and ASA, 1989a). The reported flux
values range from approximately 2 to 6 pounds of PCBs daily.
These PCBs are ultimately transported to portions of the
Lower Harbor and Buzzards Bay, where they are redeposited,
volatilized into the atmosphere, or taken up into the food
chain by aquatic biota. The PRPs fate and transport
modeling (ASA, 1989b, and Thibodeaux, 1989c) provides
consistent results, supporting the evidence that PCBs are
migrating from the Site. The results of these studies
indicate that the estimated PCB flux from the estuary
sediments ranges from 3 to 36 Ibs/day. The PRPs estimate
that approximately half of these PCBs volatilize into the
atmosphere.

The following paragraph is a summary of the more detailed
description of the movement of PCBs from the bed sediment
into the overlying water, which is provided in the HSFS.

The movement from the sediment to water column is the result
of many mechanisms including physical, chemical, and
biological processes. However, the overall mass transfer is
primarily a function of the concentration gradient between
the bed and the overlying water column and the erosion or
deposition of contaminated sediment particles. Since the
Estuary and Lower Harbor are depositional in nature, PCB
migration through resuspension does not appear to be a major
transport mechanism. (The PRPs suggest that the deposition
of sediment particles may act to cover contaminated
sediments. However, the results of studies conducted for
EPA (Battelle, 1989) indicate that suspended sediment
becomes contaminated with PCBs from contact with the water
column prior to settling.) The processes which move PCBs
both out of and back into the bed depend on the local
conditions. Finally, of the many mechanisms occurring

4-3
-------
within the sediment, EPA believes the following contribute
significantly to the mobilization of the PCBs:

desorption of PCBs from the bed sediment'and diffusion
into the overlying water;

molecular diffusion of PCBs within the pore water of
the sediment; and

bioturbation, or mixing of the sediment by organisms.

In summary, EPA believes the Hot Spot continues to function
as a source of PCBs for the remainder of the Estuary and
Lower Harbor/Bay. Studies by the USAGE, Battelle, and
others cited in the Hot Spot Feasibility Study (HSFS) have
documented the fact that PCBs move from the sediment into
the water column and are transported via tidal pumping into
the Lower Harbor and Bay. PCB concentrations in the Hot
Spot sediments and water column above the Hot Spot are
orders of magnitude higher than PCB concentrations in other
areas of New Bedford Harbor.
4.2 COMBINED SEWER OVERFLOW (CSOl LOCATIONS

DCN #3, Page 2

"PCB contamination at the lower depth (1 to 4 feet;) is
limited to areas primarily around the storm water overflows
and combined sever outfall discharge pipes* This
contamination at depths grater than 1 foot can be attributed
to turbulence and subsequent mixing and deposition of
contaminants that occurs around discharge areas,* This
argument, while potentially true, is not supported by any
analysis or reference to the literature. The hot spot FS
report doesn't show the location of• the combined sewer or
storm water discharge nor does it document the flow rates or
pollutant loads discharging to the area*

The contamination at depths greater than 1 foot in the
has little to do with turbulence ihd
mixing. In the vicinity of most shallow outfalls
tf of ecour caused by the strong currents generated
If discharge« As the momentum of the discharge
dissipates^ ^articulate material carried in the flow; or
eroded from the bottom deposits.on the sea bed. Once on the
sea bed, bioturbation and diffusion transport the particle
bound pollutant associated with the discharge deeper into
the sediments, Resuspension and transport are also possible
in high current areas or regions with substantial wave
activity*

4-4
-------
DCN #3, Page 4

The current Hot Spot areas correspond to the locations of
the storm water and combined sewer outfall", .-•:.. -There iis no
evidence presen ted to show that the Hot Spot areas
correspond'., to .locations of -storm;.;. or .; combined "
'"""" ^•"••••v-v-v""v~'^
EPA RESPONSE 4.2

The locations of industrial discharges and combined sewer
overflow pipes are presented in an EPA document entitled,
"Historical Assessment of the Aerovox-PCB Related Facility
New Bedford, Massachusetts'* (1982) and the City of New
Bedford sewer maps. The Historical Assessment was conducted
using historic aerial photographs of the Aerovox facility
taken in 1951, 1962 and 1974, U.S.G.S. topographic maps, and
Sanborn Map Company fire insurance maps.

EPA compared these discharge locations to the distribution
of PCBs. EPA found a direct correlation between areas of
significant PCB contamination and the discharge locations
adjacent to the Aerovox facility. These locations are shown
in Figures 4-2, 4-3 and 4-4 at the end of this Section.

The Historical Assessment also revealed several trenches and
a discharge pipe from the Aerovox facility that emptied into
the Acushnet River Estuary. Analysis of the April 10, 1962
photograph revealed plumes in the estuary at several of
these locations indicating discharge.

EPA acknowledges that erosion and scour may occur at an
outfall discharge. However, immediately downstream of these
erosive areas there is subsequent deposition. This explains
why the highest levels of PCB contamination are not at the
terminus of the discharges but slightly offshore.
4.3 ATMOSPHERIC TRANSPORT

DCN #2, Page 14, Comment

Throughout^ the report atmospheric transport of PCBs is given
only cursory treatment. Thibodeaux 1989, in Ilia work for
the U.S. Army Corpsr has shown that evaporative losses may
be very significant, in the upper estuary»;
4-5
-------
DCN *3, Page 3
It seems unusual that the discussion on volatilization from
the -water column doesn't include reference to Thibodeaux's
( 198 9b) recent work sponsored by the U.S. Army Corps on the
problem.... Thibodeaux (1989) has shown that the evaporative
processes account for approximately 40% of the loss of PCBs
from the upper estuary. It seems that this potential route
......... " ""'""""•""" ' "'•"
EPA RESPONSE 4.3

EPA has considered atmospheric transport from the Hot Spot
Area, including both PCB emissions from the mudflat areas of
the Hot Spot and from the water column area of the Upper
Estuary impacted by the Hot Spot.

EPA's evaluation of the mudflat areas has included both air
monitoring and air modeling activities. Results of the PCB
emission modeling completed by EPA (EPA, 1987a and EPA,
1987b, Thibodeaux, 1989a and Thibodeaux, 1989b) and modeling
completed by the PRPs (Thibodeaux, 1989c) indicate that the
highest PCB emission potential exists for exposed wet
sediment. These findings are significant since a large
portion of the Hot Spot is exposed at low tide.
Additionally, these studies indicate the next highest
emission potential is from the site areas with the. highest
PCB levels in the water column. These modeling predictions
correlate with the observed data from air monitoring studies
conducted at the site over the past ten years. The
consistent finding of these air studies is the
identification of the northern portion of the Estuary as a
source area for volatile PCB emissions.

Air monitoring conducted by EPA and Environmental Science
and Engineering (ESE) in January 1978 reported results of
490 ng/m3 to 774 ng/nr downwind of the Aerovox facility. The
upwind results reported for same period were 5.6 ng/nr.
During September of 1978, the reported downwind values
ranged from 268 ng/m3 to 310 ng/m3.

In 1982, an area wide air monitoring program was conducted
to assess the ambient levels of PCBs, trace metals and other
organics within the greater New Bedford area (GCA, 1984) .
This comprehensive effort included monitoring stations
located in New Bedford, Acushnet and Fairhaven. The
monitoring locations were selected to provide ambient levels
from both known and potential source areas and urban
background levels. High PCB levels were reported for
several of the known source areas, including the northern

4-6
-------
end of the Estuary. Two of these sampling stations were
located downwind of the Hot Spot area and experienced
average PCB concentrations of 69 ng/m3 and 88 ng/m3. The
study also reported average ambient PCB levels for the
background stations ranging from 3.7 ng/m to 16 ng/m3. One
of the recommendations of this 1984 study was a more
detailed monitoring program for the northern portion of the
estuary to investigate the role of tidal influence on PCB
emissions and to evaluate potential temporal changes.

In 1985, an air monitoring program was conducted by EPA
(NUS, 1986) to further investigate contaminant emissions
from the highly contaminated sediments in the mudflat area
adjacent to the Aerovox facility. The objective of this
study was to examine the potential role of tidal influence
on releases PCBs and trace metals from this area. The
program consisted of four sampling locations along the
shoreline of the estuary and one background location away
from the site. The measured PCB values (Aroclor 1242)
ranged from a low of 7ng/m3 at the background location to a
high of 471 ng/m3 at the sampling site directly east of the
Hot Spot area. This sampling location was downwind of the
mudflat area for a portion of each sampling period and
consistently experienced the highest ambient PCB (Aroclor
1242) levels of all the locations. The results of seven
samples taken at this location during periods of high and
low tide indicate that PCB (Aroclor 1242) concentrations
increased during periods of low tide.
>

EPA conducted an ambient air monitoring program during the
pilot dredging study in 1988 and 1989. The report
describing this air monitoring program and its results are
scheduled for completion in April 1990. A discussion of
this program is provided in EPA Responses 2.4.3 and 8.5
found in Sections 2 and 8 of this Responsiveness Summary,
respectively.

As part of the second operable unit, EPA is evaluating
volatile PCB emissions from the water column as a fate and
transport process. The evaluation will include the use of
the New Bedford Harbor fate and transport model. The
evaporative coefficient (k =1.12 m/d) value used in the
model is similar to the value used by the PRPs (kc - 1.68
m/d) in their studies (Thibodeaux, 1989c and ASA, 1989).

###
4-7
-------
Section 4 References
ASA, 1989a. Tidal Cycle Flux Measurements," (DCN #21).

ASA, 1989b. "Use of Simple Box Model to Estimate PCB Water
Column Concentrations Before and After Capping in the Upper
Estuary, Draft," (DCN #29).

Balsam, 1989. "A Remedial Action Program, New Bedford
Harbor Site, Attachment D, New Bedford Harbor Thin Layer
Sampling Program," (DCN 119).

Battelle, 1989. New Bedford Harbor Database (hard copy
printout), prepared for Ebasco Services, Incorporated.

EPA, 1978. Memorandum from Richard J. Siscanaw to Edward L.
Taylor through Arthur E. Clark reporting the ambient PCB
levels from the New Bedford area.

EPA, 1983. "Aerovox PCB Disposal Site; Acushnet River and
New Bedford Harbor, Massachusetts; Tidal Cycle and PCB Mass
Transport Study," Environmental Response Team, Edison, NJ.

EPA, 1982. "Historical Assessment of Aerovox-PCB Related
Facility - New Bedford Massachusetts."

EPA, 1987a Memorandum - Estimation of Ambient Air .
Concentration at the Contaminated Harbor.

EPA, 1987b Memorandum - New Bedford Harbor Site; PCB
Emissions from CDF.

ESE, 1978. Letter from Charles L. Stratton to Dr. Thomas
Spittler reporting ambient PCB levels from samples taken in
January 1978.

GCA Corporation, 1984. "New Bedford Environmental
Investigation -Ambient Monitoring Program."

NUS Corporation, 1986. "Ambient Air Monitoring Program for
Acushnet River "Estuary - New Bedford, Massachusetts," Volume
I.

Teeter, Allen Jf. 1988. New Bedford Harbor Superfund
Project, Acushnet River Estuary Engineering Feasibility
Study of Dredging and Dredged Material Disposal
Alternatives; Report 2, "Sediment and Contaminant Hydraulic
Transport Investigators," Technical Report EL-88-15, U.S.
Army Engineer Waterways Experiment Station, Vicksburg, MS.
4-8
-------
Thibodeaux, 1989a. "Theorical Models for Evaluation of
Volatile Emissions to Air During Dredged Material Disposal
with Applications to New Bedford Harbor, Massachusetts,"
Miscellaneous Paper EL-89-3, US Army Engineer Waterways
Experiment Station, Vicksburg, MS.

Thibodeaux, 1989b. "Theoretical Models for Volatile
Emissions from Dredged Material - Comparison of Predicted
and Laboratory Measurements for New Bedford Harbor
Sediment."

Thibodeaux, 1989c. "Theoretical Evaluation of the
Effectiveness of Capping PCB Contaminated New Bedford Harbor
Sediment," (DCN #16).
4-9
-------
CUMULATIVE PERCENTAGE OF PCBs

RE-LEASFD FROM UPPER ESTUARY
100
90
i

25.000 15.000 10.000 5.000 2.000 1.000 500

CONCENTRATION IN SEDIMENT (PPM)
CUMMULATIVE
PCS FLUX
4-10
-------
TOTAL PCBs*
SO • 500 ppm'

300 • 4000 ppm

>40OO ppm (HOT SPOT)
DISCHARGE LOCATIONS FROM HISTORICAL ASSESSMENT'
.uoo FE;
REFERENCES

I. Illllrtny AMM
FIGURE 4-2

INTERPRETATION OF
TOTAL PCB CONCENTRATIONS-
DEPTH: ZERO TO 12 INCHES
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOR
• SUM OF AVAILAIJLE AIIOCHI.OH OAIA
-------
I
•—•
N)
" i " i _ " i " i _ 'f I 1 I » I _ !t_i
!t_i _ «.»«.»».»». _ >«.».»«.!'.»«.»». »« | . >! , ?J
)« . I)
BEfEREMCES
(CM|
.120* FEET
FIGURE 4-3

INTERPRETATION OF
TOTAL PCB CONCENTRATIONS-
DEPTH: 12 TO 24 INCHES
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOR
• SUM OF AVAH.ABLE AROCItlOH DAIA
-------
1 TOTAL PCBs

o
DISCHARGE LOCATIONS FROM HISTORICAL ASSESSUENT
SO • 500 pen

too • 4000 ppn

>4000 pfm(HOT SPOT)
»*. to
* kMi
ky ««•»»• O«^ »•• ltd to IMC
REFERENCES
•I JUIWM • PCB lUtato* r««k • MM ••••«, Mi
(00|
FIGURE 4-4

INTERPRETATION OF
TOTAL PCB CONCENTRATIONS
DEPTH: 24 TO 36 INCHES
HOT SPOT FEASIBILITY STUDY
NEW BEDFORD HARBOR
-------
SECTION 5.0 - BIODEGRADATION Of PCBS

5.1 NATURAL BIODEGRAD&TIQN AS AN ALTERNATIVE TO REMEDIAL ACTION

OCN #1, Page 6, Paragraph 3, Comment 1

...It is asserted that there is inadequate data to estimate
the half lives of PCBs as a result of biodegradation. This
assertion is incorrect. Sued) data have been submitted.
Moreover, the Agency could add nutrients to the site to
speed up the process. The Agency has chosen to relegate the
dechlorination issue to the scrap heap because it i«
inconsistent with the Agency's pre-determination that
dredging must occur*

DCN #31, Section 7.4.9.10

Despite the recognition is this section of the HSF8
anaerobic biodegradation is occurring in New Bedford Harbor,
no attempt is made to take advantage of this natural process
in the design of the recommended remedial alternatives,'
despite recommendations by EPA's own experts.

EPA RESPONSE 5.1

EPA has considered the evidence of natural biodegradation of
PCBs in New Bedford Harbor submitted by the PRPs (Yoakum, et
al., on behalf of AVX, and several versions of a report by
Brown and Wagner on behalf of Aerovox). EPA has also funded
its own research at the Environmental Research Laboratory in
Narragansett, Rhode Island, the results of which are
described in a report by Lake, et al. (1989). EPA has not
accepted all of the assertions of Yoakum and Brown and
Wagner, but EPA has also found that even on their own terms
these papers do not establish that natural biodegradation
would be acceptable as an alternative to remedial action,
particularly in the Hot Spot, which appears from these
papers to be at least partly unaffected. The evidence does
not demonstrate that natural biodegradation will abate the
risks to public health and the environment, particularly the
risks of contamination of the food chain, in anything less
than decades, or indeed at any time in the foreseeable
future.

EPA's concern here is limited to the Hot Spot; EPA continues
to consider these issues for the second operable unit for
the lower levels of contamination.

Evidence exists that the patterns of PCB congeners in some
sediment samples have altered relation to presumable*
starting mixtures of Aroclors 1242 and/or 1016, and 1254.

5-1
-------
Such alterations include losses due to dissolution and
evaporation, but also include decreases i-n the content of
specific PCB congeners and buildup of other congeners in
some samples (Lake, et al.). EPA has not found evidence
which conclusively elucidates the causes of these pattern
alterations, but for purposes of this discussion, EPA
assumes that these alterations result from dechlorination of
molecules, and that the dechlorination process is likely to
be microbially mediated.

In general, EPA has found that the evidence of natural
biodegradation shows it to be widely variable,
unpredictable, and generally a slow process. The research
conducted by EPA at its Narragansett laboratory found that
the extent of dechlorination, and the apparent rates at
which it has progressed, vary widely from one location to
another, between the surface and various depths within a
single core sample, and from one PCB congener to another
(Lake, et al.). PRP's reports (Yoakum and Brown and Wagner)
show that in some of the most highly contaminated locations,
little or no dechlorination has taken place. Brown and
Wagner calculated that natural biodegradation would take
fifty years or more to eliminate PCB congeners which affect
the food chain. Using Brown and Wagner's data, EPA
calculates that the time required to reduce a sediment PCB
concentration of 4,000 ppm to 50 ppm would be approximately
50 to 350 years. PCB concentrations in the 100,000 ppm
range, such as found in the Hot Spot, would require
approximately 85 to 600 years for reduction to a 50 ppm
level. Thus, both the rates and the areal extent of
dechlorination are too variable, and the underlying process
too poorly understood, to allow any projections as to future
trends that would allow EPA to find this process to be an
acceptable alternative to remedial action.

The report by Yoakum, et al. identifies two locations within
the Hot Spot with PCB levels of 76,000 ppm and 130,000 ppm
where no evidence of biodegradation was reported. In a map
included in the report, the authors designated the grid
closest to the Aerovox facility as an area where no
dechlorination is taking place (Yoakum et al., Appendix VI
at 26-36). At least one sample analyzed by Brown and
Wagner, Sample #18, appears to have revealed little if any
dechlorination.

The PRPs identify many other locations where they observe
varying degrees of alteration. It is not possible for EPA
to fully evaluate all of these findings, which are based on
evaluations of their own sampling and analyses and are based
on documents which have not been submitted to EPA. Aside
from their own analyses, the authors base their conclusions
on reviews of analyses by the government, which were not

5-2
-------
performed for the purpose of evaluating dechlorination
patterns. The chromatograms generated with packed column
analyses do not have sufficient resolution of individual
congener peaks to be fully reliable as a means of assessing
the rate and extent of dechlorination.

Similarly, Brown and Wagner base their conclusions in part
on packed column chromatograms. Thus, EPA cannot accept as
definitely demonstrated the assertions of these reports
concerning the areal extent of microbial activity. From
EPA's research, it appears that the area of significant
dechlorination may be far more limited than asserted by the
PRPs.

EPA's report (Lake, et al.) documents extreme variations
found at different locations. Decreases in abundance of
presumably dechlorinated congeners were most pronounced in
the sample taken farthest up the Estuary, and within that
sample, were most pronounced at the 6-7 inch depth. For two
samples, one located south of the Coggeshall Street Bridge
and one near the Hurricane Dike, their report concludes that
the patterns "may demonstrate initiation of dechlorination
in these samples or may reflect down bay transport and
deposition of partially dechlorinated residues." Thus, the
outer limits of the area in which dechlorination is taking
place cannot be defined with the available evidence, and the
possibility of transport and redeposition of dechlorinated
residues cannot be ruled out as an alternative mechanism for
creating dechlorinated patterns at some locations.

Within the Upper Estuary, EPA's researchers found that
calculated half-lives of one congener at different locations
varied from 465 years to 13.2 years. At one of the sample
locations, two important congeners, (IUPAC Nos. 118 and 153)
showed no relative decrease in quantity. (The designations
of different PCB congeners by IUPAC numbers and structure
codes is described in full in the article by McFarland and
Clark in the Administrative Record. Appendix A in the
article lists the numbering and structure codes for 209 PCB
congeners.) As discussed below, these two congeners play a
significant role in the contamination of the food chain.
EPA's study found that PCBs in biota samples from the Upper
Estuary had not been affected by dechlorination. Even at
the most extensively dechlorinated location, the half-life
of congener 153 was calculated at 18.8 years; similarly, the
rates of dechlorination for 153 calculated by Brown and
Wagner would take decades — fifty years or more — to
effectively remove it from the environment.

The PRP's comments assert that the effects of the
dechlorination pattern or patterns which they have
identified can be equated with "detoxification." The PRPs

5-3
-------
derive the notion of "detoxification" from the (supposed)
findings of others concerning the relative toxicity of
different PCB congeners. EPA regards the evidence as
insufficient to warrant the conclusion that the
dechlorination found in New Bedford can be equated with
"detoxification," even in the locations in which such
dechlorination is most pronounced. EPA finds that the
toxicity of dechlorinated residues, and the extent to which
dechlorination has altered the toxicity from that of the
original Aroclors, are unknown. This issue is also
discussed in Section 3.0 of this Responsiveness Summary*

Although EPA recognizes that studies have shown that certain
PCB congeners may be more potent than others in respect to
certain kinds of toxicity, those congeners are not
exclusively the only toxic congeners. No specific congeners
have been indisputably identified as the cause of the
carcinogenicity and other effects which Aroclor mixtures
have been shown to have on laboratory animals. Indeed, as
the PRP's comments recognize, the role of the supposedly
more toxic structures in respect to carcinogenicity is
controversial and unresolved (Whysner, Appendix E).
Therefore, it is not possible for EPA to identify a non-
toxic residue which dechlorination can be expected to
create.

The PRPs have not shown that biological dechlorination will
eliminate contamination by PCB congeners of known .toxicity
in anything short of decades. In a report by Brown and
Wagner, after asserting that "detoxification1* would occur in
13 years (plus or minus 5), the authors conceded that a
different dechlorination rate would have to be calculated
for those PCB congeners which are most persistent in
crustaceans, birds, mammals, and man. Brown and Wagner
wrote the following:

The most persistent PCB congeners in all these groups
of species (which share the ability to biodegrade most
PCB congeners by microsomal oxidases of the cytochrome
P-450 type) are those having a 2,4,5 - or 2,3,4,5 - CB
group attached to any other 4- substituted CP, e.g., 4-
, 2,4-, 3,4-, 2,3,4-, 2,4,5-, etc. ... [The
dechlorination found in New Bedford] does attack all of
these congeners, but sometimes only slowly, notably in
the case of 245-245 CB, for which the t - 1/2 may be
estimated only roughly from the available data (Table
2) as about 35 years. We estimate that to achieve 90%
overall reduction in the level of P450 resistant
congeners in the s^dlmen
-------
The data on which this calculation was based ("Table 2")
first became available to EPA in January 1987, as part of
the Requests for Admission ("RFAs") submitted to the United
States by Aerovox in the New Bedford Harbor litigation. The
RFA version of Table 2 has been included in the
Administrative Record at 11.12.8. From this Table/ it is
apparent that research into biodegradation reveals extremely
slow degradation periods for the group of PCB congeners
referred to in the passage above as the P450 resistant
congeners. The numbers in Table 2 appear to be averages
based on all sampling sites. As discussed above, it is
evident that rates vary considerably from location to
location. Even where dechlorination is well advanced,
however, the calculated half-lives for congeners such as
2,4,5-2',4',5', describe change in terms of decades. Lake,
et al., calculated an 18.8 year half-life at the most
dechlorinated location, and no decrease in relative
abundance at less contaminated site.

As discussed by Brown and Wagner, chromatograms published by
Farrington, et al., identified congeners which are
consistently abundant in the PCBs in New Bedford lobsters
(Farrington, et al., 1979). The substantial presence of
these congeners was subsequently confirmed by Pruell, et
al., in the report which is now Appendix E to the draft
Public Health Risk Assessment (Ebasco, 1989). These
congeners include IUPAC numbers 118, 138 and 153, or
2,4,5,3',4'; 2,3,4,2',4',5'; and 2,4,5,2',4',5'. The half-
lives for these molecules provided by Brown and Wagner's
table are respectively, 25, 12.5 and 35 years, plus or minus
10 years. Congener 153, or "245 - 245", is the congener
discussed in the passage quoted above. It is not clear how
Brown and Wagner calculated that 90% of the congeners would
degrade in 50 years; in fact, a half-life of 35 years would
mean that after 105 years 12.5% of 153 would remain.

These three long-lived congeners are not toxicologically
insignificant. Research shows (Safe, et al.) that
2,4,5,3',4* (118) is among a group of "raono-ortho
substituted1* PCBs whose toxic effects are similar to those
of 2,3,7,8-TCDD (dioxin). The same article identifies to
2,3,4,a1,4',5' (138) as an active enzyme inducer "which has
been shown to be porphyrinogenic in rats after long term
feeding studies.1* They also identify 2,4,5,2',4*,5* (153)
as an enzyme inducer. (Safe is also one of the authors of
one of the documents submitted by the PRPs, DCN #7).

An attempt to classify PCB molecular structures according to
known structure activities and environmental significance
has been published by Victor A. McFarland and Joan U.
Clarke, two researchers at the Army Corps of Engineers'

5-5
-------
Waterways Experiment Station (McFarland and Clarke, 1989).
Summarizing the toxicity to both humans and aquatic species,
and the relative abundance of various congeners, McFarland
and Clarke identified four priority groups of PCB congeners.
McFarland and Clarke use mixed-function oxidase induction as
the benchmark of toxicity for this classification. Although
EPA does not regard this as the only measure of PCB
toxicity, and McFarland and Clarke's proposal has not been
adopted as a regulatory approach, their article provides a
useful analysis and summary of the structure-activity
research from which Brown and Wagner apparently derive their
concept of "detoxification."

All of the congeners which-McFarland and Clarke place in the
highest priority group were identified in substantial
quantities in New Bedford lobsters and fish. (Pruell, et
al.). In addition, the three most abundant congeners, 118,
138 and 153, are all identified as toxic or potentially
toxic congeners. Both 118 and 138 are included in the
proposed highest priority group described as a class of
abundant PCBs for which substantial evidence of toxicity
exists. 153 is included in Group 2, which consists of
environmentally abundant congeners which exhibit
"phenobarbital-type induction," so that they are of lesser
toxic potential than Group 1, but still should be regarded
as substances of potential toxicity.

No data has emerged since which would change the finding
that these congeners have extremely slow rates of loss,
rates which would require decades to complete their effect.
Nevertheless, EPA has continued to review evidence of
natural biodegradation of PCBs as it has become available,
and funds its own related research. Contrary to the PRP
comments, the research by Dr. Lake was not research which
the Superfund program has failed to consider. Rather, this
work was funded by Superfund, and the results were placed in
the Administrative Record as soon as they were available.

In the course of the Feasibility Study, EPA contractors
(E.C. Jordan) solicited in-put on the subject of
biodegradation from General Electric, and subsequently from
the Corps of Engineers and EPA's Narragansett Laboratory.
The responses to E.C. Jordan's requests are all in the
Administrative Record. EPA also requested proposals for
bench tests of biodegradation treatment technologies and
subsequently funded a test by Radian Technology. The
results of this test are also in the Administrative Record.

The Administrative Record also includes a long history of
correspondence with the PRPs to obtain information on
biodegradation. This correspondence was initiated when the
General Electric Company referred an EPA contractor's

5-6
-------
inquiry to Dr. Brown, who wrote to EPA (E.G. Jordan) that he
had written a report on his research in New Bedford which
could only be obtained from Aerovox's attorneys. This same
report was cited as support for comments submitted to EPA on
the Detailed Analysis of Remedial Technologies. In spite of
repeated requests by EPA, the report was not made available
until it was sent to the Department of Justice in January of
1989, over two years after it was first requested, and only
after the United States' Motion to Compel Production of the
report had been granted by the District Court. The copy of
the report produced was dated September 1986. Certain
portions of the text had been redacted by Aerovox's
attorneys.

EPA has subsequently received a new version of the Brown and
Wagner report. This new version was submitted with the PRP
comments. Another version was apparently used to create
Requests for Admission presented to the United States in
January 1987. The RFAs contain material which corresponds
to the redacted spaces in EPA's copy of the September 1986
report. (EPA has included the attachments to the Requests
for Admission submitted to the Justice Department by
defendants in litigation in the Administrative Record to the
extent that they provide information relevant and necessary
to consider in the choice of a remedy. However, EPA has not
acceded to the defendants' assertion that all the RFAs
should be added to the record, as many of these RFAs are
entirely irrelevant to the choice of a remedy, and. in any
case the RFAs do not in themselves represent demonstrable
information to be considered in the choice of a remedy.)

Although each version of the Brown and Wagner report has
been edited differently, they present the same data. Only
the September 1986 version contains the paragraph quoted
previously. However, the half-life data in the table on
which the "50 years from the present" calculation was
apparently based is presented in all versions.

Brown and Wagner base this conclusion in part on the results
of analyses of water samples. They conclude that "at the
time of sampling the estuarine waters included some masses
containing relatively higher levels of quite heavily altered
... PCBs and some masses containing somewhat lower levels of
almost unaltered PCBs, with relatively little mixing between
them" (p. 13); leading to the conclusion that "the water-
borne PCBs ..-, must have been derived partly from the
sediments of the upper and middle Estuary, and partly from
local, outer harbor sediments" (p.24). While EPA is not in
a position to-fu-lly evaluate this conclusion (documentation
of the water sample analyses has never been provided.to EPA,
in spite of repeated requests and assurances from Aerovox
that it would be provided), it is worth noting that it is

5-7
-------
consistent with EPA's findings that PCBs from the upper
Estuary are being transported into the outer harbor, and
would continue to be so transported throughout any period of
time in which natural biodegradation might be relied upon as
a substitute for remedial action.

In conclusion, EPA has made extensive efforts to consider
all available information on natural biodegradation, and,
along with the Department of Justice and the Massachusetts
Attorney General's Office, has expended considerable effort
trying to obtain from Aerovox the very information Aerovox
was demanding that the government consider. EPA has
concluded, upon examination of the evidence, that it could
not possibly support a decision to select natural
biodegradation as an alternative to a remedy for the Hot
Spot. EPA will continue to consider the relevance of
natural biodegradation, including any new information which
may become available, for the second operable unit.
5.2 BIODEGRADATION AS A TREATMENT TECHNOLOGY

DCN #31, Section 7.7.6
The "" "overview ':'o"f " the "Bench-Scale
Program , New Bedford Harbor Feasibility Study" >Ebascc
Services Inc. V August 1989 states that considerable research
and process development is needed to implement enhanced
biodegradation and more specific information is needed, to
compare effectiveness, implementation and cost* These
arguments' apply. with equal force to the recommended"
alternatives. Handling heavy metals with incineration, in
particular, requires additional research and process
development-prior to design; Indeed, much additional
information is needed to compare the effectiveness,'
implementation and cost of alternatives. This is another
example "-'of -Athe: ;:^ri:>itrary^nature of the alternative
..............
DCN #31, Section 7.7.8

The ,d|lc«ission of enhanced in-situ biodegradation on p. 3-37
discat^~ the consideration of the alternative prior to its
development for consideration because the technology has not
been successfully demonstrated in a marine environment.
Contrary to law, no serious attempt is made to consider
engineering methods which might make this technology
feasible."'"
5-8
-------
EPA RESPONSE 5.2

Natural (i.e., in situ) biodegradation is a process by which
contaminants are degraded by indigenous micro-organisms
without removing the contaminated medium from its location.
The micro-organisms may operate in either an aerobic
(oxygen) or anaerobic (oxygen-free) environment. The rate
of biodegradation may be increased by nutrient addition to
the contaminated medium in order to enhance the
biodegradation capabilities of the indigenous microbes, or
by the introduction of specially adapted (through selective
cultivation or genetic engineering) micro-organisms.

Natural biodegradation as a remedial treatment process has
been successfully applied to groundwater and soil
contaminated with constituents other than PCBs, such as
volatile and aromatic hydrocarbons. Numerous vendors offer
commercial-scale bioremediation services employing natural
biodegradation for these types of wastes.

Natural biodegradation of PCBs as a remedial treatment
process was evaluated during the initial screening and
detailed evaluation of treatment technologies for New
Bedford Harbor. This work was conducted during the spring
and summer of 1987 and the results were published in two
reports (E.G. Jordan/Ebasco 1987 a,b). Based on the
available research and state-of-the-art process development
at that time, EPA concluded that: (1) there was no
conclusive evidence for the occurrence and mechanisms of
natural biodegradation of PCBs, and (2) natural PCB
biodegradation as a. remedial treatment process had not been
successfully demonstrated in any environment.

Since the publication of the treatment technology reports in
1987, numerous studies have provided scientific proof that
natural biodegradation of PCBs is occurring in the sediments
of New Bedford Harbor and elsewhere. However, no attempt
has been made to implement a field demonstration of
biodegradation as a remedial process in river or harbor
sediments. General Electric, the principle PRP in the PCB
contamination of the Hudson River, has recently announced
plans to demonstrate an in-river enhanced bioremediation
system within the next two years. At the present time,
however, none of the engineering obstacles for implementing
this system have been addressed in the conceptual design (M.
Brown, 1989).

A fundamental issue that has not been thoroughly addressed
to date is the biochemical decay rates or half-lives of
PCBs. Reliable estimates of the PCB half-lives are critical
in determining the length of remedial time that would be
required for natural processes, such as biodegradation, to

5-9
-------
remove PCBs from the sediments. Brown and Wagner (1986)
have suggested that the half-life of heavily chlorinated
PCBs may range from 7 to 50 years. Based on this estimate,
the time required for biodegradation to reduce a sediment
PCB concentration of 4,000 ppm to 50 ppra (TSCA) would be
approximately 50 to 350 years. For PCB sediment
concentrations in the 100,000 ppm range (measured in the Hot
Spot), it would require approximately 85 to 600 years for
biodegradation to reduce these concentration levels to 50
ppm. There are no known rate estimates for enhanced in situ
biodegradation of PCBs in river or harbor sediments.

It is not the purpose of a CERCLA FS to promote, direct,
and/or finance research and development on innovative
treatment processes. While natural biodegradation of PCBs
(unenhanced or enhanced) may offer the potential for an
effective, low cost treatment alternative, sufficient
information and data is not currently available to address
key process design issues such as: the rates of
biodegradation; the mechanics of nutrient delivery systems
and the logistics of monitoring and/or controlling
physicochemical parameters affecting microbial growth and
degradation capacities in unconfined sediments; and costs.
Consequently, the effectiveness, implementation and cost of
natural biodegradation as a remedial treatment process could
not be assessed during the Hot Spot FS and no comparisons
could be made with other treatment technologies (e.g.,
incineration, solvent extraction) being evaluated -and for
which this information was available.

The lack of information and data on natural biodegradation
stands in stark contrast to the abundance of available
information and data on treatment technologies such as
incineration, solidification, and even solvent extraction.
It is a fundamentally different process to engineer a
solution to immobilize metals than to "consider engineering
methods with might make this technology [enhanced in situ
biodegradation] feasible." The former will require
additional testing to find a formulation of solidifying
agents (from among the dozens currently available) to
immobilize metals in incinerator ash. This is a process
optimization problem. The latter will require extensive
research, development and testing of prototype systems to
achieve a workable solution.. This is a process design
problem.

### .
5-10
-------
section 5 References;

Brown, John F., and Robert F. Wagner, 1986. "Polychlorinated
Biphenyl (PCB) Movement and Transformation in Acushnet
Estuary Sediments;" prepared Brown and Wagner of General
Electric Research and Development Center, Schenectady, New
York.

Brown, Mark. 1989. Personal communications between Mark
Brown, Chief of the Special Projects Division for the New
York State DEC, and Douglas Allen, E.G. Jordan. November
27, 1989.

E.C. Jordan Co./Ebasco, 1987a. "Initial Screening of
Nonremoval and Removal Technologies for the New Bedford
Harbor Feasibility Study;" prepared by E.C. Jordan Co. for
EPA.

E.C. Jordan Co./Ebasco, 1987b. "Detailed Analysis of
Remedial Technologies for the New Bedford Harbor Feasibility
Study;" prepared by E.C. Jordan Co. for EPA.

Farrington, John W., 1979. "PCB Analysis - Results of
Samples Taken in New Bedford Harbor and Buzzards Bay
Analyzed by Massachusetts State and U.S. Federal Labs, and
Woods Hole Oceanographic Institution;" Woods Hole
Oceanographic Institution.
4
Lake, James L., Richard J. Pruell, and Frank A. Osterman,
1989. "Dechlorination of PCBs in Sediments of New Bedford
Harbor;" U.S. EPA Environmental Research Laboratory.

McFarland, Victor A. and Joan U. Clarke, 1989.
"Environmental Occurrence, Abundance, and Potential Toxicity
of Polychlorinated Biphenyl Congeners: Considerations for
Congener-Specific Analysis," U.S. Army Waterways Experiment
Station.

Safe, Stephen et al. "PCBs: Structure-Function
Relationships and Mechanisms of Action;" Environmental
Laboratory, Department of Physiology and Pharmacology, Texas
A&M University.

Whysner, John, Peter Shields, and Kenneth H. Chase, 1989.
"Recent Findings Regarding the Toxicity of PCBs -
Implications for the Acushnet Estuary Risk Assessment."
(DCN #7)

Yoakum & Associates, and Balsam Environmental Consultants,
1989. "PCB Biotransformation in Aquatic Sediments:' New
Bedford Harbor and Other Sites." (DCN #30)
5-11
-------
SECTION 6.Q - NO-ACTION ALTERNATIVE/NO-ACTION RISK

6.1 NO ACTION ALTERNATIVE

DCN #1, Page 7, Paragraph 2, Comment 1

...It is asserted that the overall remedial strategy for New
Bedford Harbor may include a no-action alternative for the
upper estuary. If that is so, then I submit that: dredging
the hot spot is patently inconsistent with the ultimata no
action remedy, unless the Agency has concluded that
everything is consistent with a possible no-action
alternative* Obviously, that conclusion is not rational or
at least is not reasonable.

EPA RESPONSE 6.1

By choosing to divide a site into operable units, EPA has
implicitly rejected the "no action" alternative for an
entire site.

When EPA determines that operable units are appropriate for
a site, the "no action" alternative is evaluated for each
operable unit. This alternative is evaluated in a
Feasibility Study to serve as a comparison for other
remedial alternatives under consideration. In its study of
possible remedies for the remaining portion of the New
Bedford Harbor Site, EPA is evaluating a number of
alternatives, including a "no action" alternative.

EPA believes that reduction of the total mass of PCBs will
be consistent with any remedy likely to be chosen for the
entire Harbor.
6.2 NO ACTION RISK

DCN #1, Page 6, Paragraph 4
In chapters 6 arid 7, the EPA contractor refers to the no-
action alternative, but does not adequately consider that
optio^V Jn/£act'^ it is-patently evident that', particularly
wil^/r«|pect,to any interim remedial action for the hot
spotisr€he'no^action alternative is the appropriate choice*
First, on page 6-6, the statement is made that-public health
and environmental risks would not be mitigated to acceptable
levels by the no-action alternativeJ That statement assumes
that public health and environmental risks now~are~-*ts=-
unacceptable levels* The evidence is clearly to the
contrary. In fact, as the EPA well knows, the PCBs Have
been the harbor for perhaps 40 years or more, and there is

6-1
-------
no evidence that anybody living in and around New Bedford
has ever suffered any ill effects as a result, or,--for that
matter, that any biota have been injured. On the contrary,
the Greater New Bedford Health Effects Study demonstrates
the opposite, and it also demonstrates — according to the
government — thei success of institutional controls,:

EPA RESPONSE 6.2

The risk estimates for the "no action" alternative follow
EPA and State guidance. The assumptions made are reasonable
estimates of exposures that may occur if no action is taken
at the Site. EPA considers the risk estimates based on
contact with the Hot Spot sediment to be unacceptable.

Section VI of the Record of Decision Summary and Section 3
of this Responsiveness Summary provide the background and
details of the risk assessment and the assumptions made.
Section 3.5 discusses the Greater New Bedford Health Effects
Study in greater detail.

*##
6-2
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SECTION 7.0 - EVALUATION OF REMEDIAL ALTERNATIVES FOR HOT SPOT

7.1 SCREENING/EVALOATION OF ALTERNATIVES

DCN #31, Page 1-17

A far less drastic, and less potentially damaging r approach
than dredging would be adequate and. appropriate. Yet, such
approaches have been arbitrarily eliminated from
consideratipn by EPA without any genuine analysis;

EPA RESPONSE 7.1

Numerous comments received during the public comment period
for the Hot Spot FS criticized the EPA for failing to
"devote any resources to a meaningful consideration of
alternatives to dredging [followed by treatment and/or
disposal] as a remedy." The implied focus of these comments
is that capping as an alternative [in situ] remedy was not
fairly evaluated. Furthermore, comments asserted that the
evaluation that was conducted lacked supporting
documentation.

The Hot Spot FS was conducted in accordance with the
requirements of the Superfund Amendments and Reauthorization
Act (SARA) of 1986, and EPA CERCLA RI/FS guidelines. These
legislative requirements and programmatic guidelines
prescribe the process for conducting feasibility studies of
remedial alternatives for a Superfund site. An overview of
the FS process conducted for the Hot Spot is presented in
Figure 4-1 of the Hot Spot FS report (E.G. Jordan/Ebasco,
1989) . This process is discussed in further detail in
Section VIII of the Record of Decision Summary.

7.2 EVALUATION OF CAPPING FOR THE HOT SPOT

DCN #2, Page 12, Paragraph 2, Comment 1
the various alternatives, particularly the
portion, is uneven. The capping alternative is
for particularly harsh evaluation, again without
DCN #2, Page 13, Comment 10

It is Unclear how the impact on the adjacent wetlands
occurs.. It would seem that: capping with 3 feet of sediment
would ultimately increase the wetland area in the upper
estuary. .., The idea that this "alternative is expected to
cause increases in PCB mobility11 is clearly contrary *to

7-1
-------
field and laboratory experience that the U.S. Army Corps has
with capping (e.g., Long Island Sound, Puget Sound).

DCN #14, Page 2

AVX believes that the in place containment alternative is a
comprehensive remedy which should be selected by the Agency
not just for the hot spot but, for...the.jest

EPA RESPONSE 7.2

EPA conducted the Hot Spot FS in three phases. Phase I
entailed the identification, screening, and evaluation of
remedial technologies. EPA then used technologies retained
from these steps to develop complete remedial alternatives.
Phase II consisted of the initial screening of remedial
alternatives. Phase III consisted of the detailed
evaluation of remedial alternatives using the nine criteria
required by SARA.

In 1986 - 87, EPA conducted the identification and initial
screening of remedial technologies for New Bedford Harbor.
Details of this work were published in an interim report by
E.G. Jordan/Ebasco (1987a). During this work, capping was
identified as a potentially applicable containment or non-
removal technology for the PCB and metal contaminated
sediments in each of the three geographical study areas: the
Hot Spot, the Estuary, and the Lower Harbor. Specific types
of caps that were identified included: clay, sediment, and
sand and gravel caps (natural media); fabric caps
(geotextiles); and multimedia caps which combine natural and
synthetic media. In addition, two other containment
technologies were identified: impermeable synthetic
membranes, and chemical sealants. As a result of the
subsequent screening step, which considered the feasibility
of implementation and the effectiveness in containing PCBs
and metals, EPA retained capping for further evaluation.

EPA conducted a detailed evaluation of capping as a remedial
technology during 1987. The results of this work were
published in an interim report by E.G. Jordan/Ebasco
(1987b). This evaluation considered the applicability of
capping for each of the three geographical study areas using
three major criteria: effectiveness, implementation and
cost. EPA assessed the effectiveness of capping on the
basis of technical reliability and potential impacts to
public health and the environment. As a. technology. EPA did
not evaluate capping with respect to attainment of federal
and state ARARs and protection of public health and the
environment. Instead, the assessment of these factors was
7-2
-------
reserved for consideration of capping as a remedial
alternative.

While evaluating the implementation of a capping technology,
EPA considered factors relating to the technical,
institutional, and administrative feasibility of installing,
monitoring, and maintaining a cap.

EPA developed general cost estimates for capping in each of
the three geographical study areas from cost data presented
by NUS Corporation (1984).

Because capping satisfied the effectiveness, implementation,
and cost criteria, EPA retained capping as an applicable
technology for the three geographical study areas. Natural
materials such as clean sediments, sands, and gravel were
recommended for a cap. Clay caps were not recommended due
to: (1) low bearing strength of in situ sediments preventing
compaction of the clay; (2) high rates of erosion and
scouring of unconsolidated clay; and (3) excessive length of
time for clay to settle in the deeper subaqueous areas.
Caps constructed from geotextiles or impermeable membranes
were not considered practicable due to the logistical
problems of placement, seaming, and prevention of sediment
resuspension during installation operations.

EPA believed that hydraulic controls, such as sheet piles
and earthen embankments or dikes, would be necessary during
the installation of a cap in the Hot Spot and Estuary. The
hydraulic controls would serve to isolate the contaminated
sediment from the rest of the harbor system during
remediation, thus facilitating construction activities while
minimizing migration of contaminants.

During 1987-88, EPA combined remedial technologies retained
from the detailed evaluation step into complete remedial
alternatives for each of the three study areas. Details of
this work and the subsequent screening of alternatives were
described in an interim report by E.C. Jordan/Ebasco (1988) .
In accordance with SARA requirements for consideration of
alternatives involving on-site containment, a capping
alternative was developed for the Hot Spot. This
alternative consisted of: installing an embankment around
the Hot Spot; stabilizing the sediment within the embankment
with sand; and installing a synthetic cap over the Hot Spot
area.

EPA screened all of the remedial alternatives that were
developed for the Hot Spot based on the effectiveness,
implementation and cost criteria used during the detailed
evaluation of remedial technologies. However, additional
factors considered under the effectiveness criterion

7-3
-------
included: the ability of the alternative to meet levels or
standards of control equivalent to applicable or relevant
and appropriate standards, requirements, criteria, or
limitations (ARARs), long-term reliability, and the
potential need for replacement due to failure. As a result
of the screening step, EPA eliminated the capping
alternative from further consideration for the following
reasons:

o EPA anticipated significant mobilization of highly
concentrated PCBs in the Hot Spot caused by dredging
and other construction activities necessary during
installation of a cap which would result in adverse
impacts to the environment;

o A synthetic cap and the embankments would require long-
term maintenance and monitoring;

o A cap would fail to provide for a permanent and
significant reduction in the mobility, toxicity and
volume of the Hot Spot sediment; and

o EPA anticipated a moderate to high potential for future
remedial action despite installation of a cap.

During the fall of 1988, the USAGE conducted a pilot study
of dredging and dredged material disposal at New Bedford
Harbor. The results of this study indicated that under
controlled conditions, contaminated sediment in the harbor
could be dredged with minimal resuspension of sediment and
no measurable migration of contamination beyond a 100 meter
radius of dredging operations. Biota monitoring conducted
during this study also showed no adverse impacts to aquatic
biota from dredging activities.

As part of the USAGE'S Engineering Feasibility Study, an
analysis of subaqueous capping was conducted. Capping
effectiveness tests were conducted to determine the minimum
cap thickness necessary to chemically isolate the
contaminated material from the overlying water column. The
test results indicated a cap thickness of 35 cm was
sufficient to provide chemical isolation. It was also
determined that an additional cap thickness of 20 cm was
necessary to prevent penetration of burrowing organisms into
the contaminated layer (Sturgis and Gunnison, 1988). The
USAGE recommended an initial cap thickness of 4 feet as an
operational requirement in order to obtain a final cap
thickness of 3 feet after consolidation. The 3-foot cap
would provide added protection and allow for localized
variations in the applied cap thickness (Averett and t
Palermo, 1989).
7-4
-------
Based on the results of the USAGE pilot study, the USAGE
EFS, information received from the PRPs, and a New Bedford
Harbor Project Team review of the 1988 development and
screening of remedial alternatives report, EPA re-examined
capping as a remedial alternative for the Hot Spot.

EPA revised its development and screening of remedial
alternatives for the Hot Spot in 1989 as part of the Hot
Spot FS report (E.G. Jordan/Ebasco, 1989). This work is
discussed further in Section 6.0 of this Responsiveness
Summary. In addition to the capping alternative developed
in the 1988 report (described above), EPA developed a second
capping alternative. This alternative consisted of covering
the contaminated sediment with a 3-foot layer of sand/silt
or clean sediment, and armoring areas of the Hot Spot
subject to erosion with graded rip-rap.

However, EPA eventually eliminated both capping alternatives
from consideration for the Hot Spot following the screening
process for the following reasons:

o Capping would require long-term monitoring and
maintenance;

o Capping failed to provide for a permanent and
significant reduction in the mobility, toxicity and
volume of the Hot Spot sediment; and
•
o Despite capping, EPA anticipated a moderate to high
potential for future remedial action.

EPA believes that any capping of the Hot Spot sediments is
not appropriate due to the magnitude of the residual risk
associated with these highly contaminated sediments. EPA is
currently re-evaluating a capping alternative for the
Estuary excluding the Hot Spot, and retains capping as a
viable alternative for portions of the Lower Harbor. The
results of this work will be presented in the Estuary and
Lower Harbor/Bay FS.
###
Section 7 References:
Averett, Daniel, E. 1988. "New Bedford Harbor Superfund
Project, Acushnet River Estuary Engineering Feasibility
Study of Dredging and Dredged Material Alternatives; Report
11, Evaluation of Conceptual Dredging and Disposal
Alternatives;" U.S. Army Engineer Waterways Experiment
Station, Vicksburg, Mississippi.
7-5
-------
E.G. Jordan Co./Ebasco, 1987a. "Initial Screening of
Nonremoval and Removal Technologies for the New Bedford
Harbor Feasibility Study;" prepared by E.G. Jordan Co. for
EPA.

E.G. Jordan Co./Ebasco, 1987b. "Detailed Analysis of
Remedial Technologies for the New Bedford Harbor Feasibility
Study;" prepared by E.G. Jordan Co. for EPA.

E.G. Jordan Co./Ebasco, 1988. "Development and Screening of
Remedial Alternatives for the New Bedford Harbor Feasibility
Study;" prepared by E.G. Jordan Co. for EPA.

E.G. Jordan Co./Ebasco, 1989. "Hot Spot Feasibility Study
for the New Bedford Harbor Feasibility Study;" prepared by
E.G. Jordan Co. for EPA.

NUS Corporation, 1984. "Draft Feasibility Study of Remedial
Action Alternatives, Acushnet River Estuary above the
Coggeshall Street Bridge, New Bedford Site, Bristol County,
Massachusetts."

Sturgis, Thomas C., and Douglas Gunnison, 1988. "New Bedford
Harbor Superfund Project, Acushnet River Estuary Engineering
Feasibility Study of Dredging and Dredged Material
Alternatives; Report 6, Laboratory Testing for Subaqueous
Capping;" U.S. Army Engineer Waterways Experiment Station,
Vicksburg, Mississippi.
7-6
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SECTION 8.0 - PILOT S':;UL)Y/DREDGING

8.1 PILOT STUDY OBJECTIVES

DCN #31, Page 5-7

This statement of objectives indicates that the selection of
dredging is a foregone conclusion and that no evaluation of
the technology or the environmental impacts of the
implementation were being undertaken,...The study was
conducted as a design study not as a method of evaluating
dredging as and applicable remedial action alternative for
the site.

DCN #35, Page 5-1

We'''''firid'''th'at'''the'''Repbrt'''ddes'''-:n^
information .or data to substantiate the claims made for the
above aspects of the proposed work*
........ *^ * ~ :•.-... :•.: :•:•:':•::•: .•;•:•.•:-.•:•:-:•:•:•:•:•:•:•:::

EPA RESPONSE 8.1

The Pilot Study was one component of the Corps of Engineers
effort to evaluate dredging and disposal methods at the New
Bedford Harbor Site. It consisted of a field demonstration
of different dredges and disposal techniques, the results of
which were provided to EPA and used by Ebasco/E.C.' Jordan in
their comprehensive feasibility study for the Hot Spot. The
Pilot Study focused on critical questions concerning
dredging in the heavily contaminated New Bedford
environment. These questions included the following:

o What is the dredge's ability to remove the layer of
contaminated sediment while minimizing the removal of
additional sediment?

o What is the sediment resuspension and contaminant
release at the point of dredging?

The technical objectives of the pilot study are discussed on
page 5-12 of the Hot Spot FS and page 4 of the Pilot Study
Interim Report.

The environmental impacts of dredging and disposal
operations were evaluated through an extensive monitoring
program which monitored conditions both in the immediate
yicinity_of the operations and throughout New Bedford
Harbor. The monitoring consisted of physical, chemical and
biological evaluations of harbor water quality and included
an air monitoring component at the confined disposal
facility.

8-1
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8.2 SCALE UP OF PILQTf ff^UDY RESULTS TO HOT SPOT

DCN #2, Page 14, Comments #12 and #13

The.report1 "relies extensively on the results of the U.S.
Army Corps of Engineers pilot dredging study to justify the
selected remediation measures. Unfortunately, references to
this work ar« generally in the form of personal
communications. As such they are not; subject to independent
evaluation and critique..».There is no rationale given as to
why the pilot dredging program performed in a cove in the
lower part of the upper estuary should apply to the hot
spot* It would appear at first glance that the areas are
substantially different. The hot spot is located in the
main channel of the Acushnet River estuary, which is more
subject to tidal and river flows than at the pilot study
site* The PCS concentrations in the hot spot are
significantly greater than those in the cove. The distance
to significant wetland is closer for the hot spot than in
the cove. The water depths are shallower in the vicinity of
the hot spot than the pilot site. These differences raise
questions to the applicability of the pilot study results
for the" hot spot.

DCN #31, Page 1-16

„..The pilot study was hot designed or implemented in;»
fashion that would generate information about h« Affects of
dredging on resuspension and transport of contaminants from
the hot spot. That information is still missing. It ls>
howeverr key to the proposed dredging program.

DCN #31, Page 1-29

Moreover, EPA has not yet analyzed the data from the pilot
dredging study to know what the overall impact of dredging
will be relative- to PCS fate and transport (although it is
clear that given the way EPA designed the study, officials
would not be able to predict that effect).
f. v.~. \ " .•...-.--•...- •.•

DCN #31, Page 5-8

The l^(|phx':selected for the pilot dredging program raises
sion^fjlpvt;'questions relative to the validity of the
information collected when compared to the overall
objectives of the program and, the applicability of the data
to evaluating: alternatives for remedial action in New
Bedford Harbor, particularly in the "hot spot". The sits of
the pilot program is a totally unrepresentative of the "hot
spot1* area and other contaminated areas of the harbor/.
8-2
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DCN- #31, Page 5-12
A''separate''vantf "distinct'^
pilot'location is whether dredging in the cove, with its low
currents;; would be representative of more dynamic conditions
in other import ions of the upper estuary. In fact,
consideration of the hydrodynamics of the upper estuary
seems to be singularly lacking in the study, either as they
exist nor or as they might be.changed by dredging itself.

DCN #31, Page 5-26

Regardless of the cause, the data are not sufficient to
extrapoiate'resuspension rates in the "hot spot* areaAbased
on the results of pilot test in the cove.

DCN #31, Page 5-33

The chemical, physical and biological databases collected
during the pilot study do not'.support the development of
dredging activities in the "hot spot" area...,The government
has made no effort to quantify that.impact or to present a
full evaluation of 'the potential water quality impacts of
the "hot spot" dredging.

DCN #35, Page S-4

In our view the proposed project is- too difficult^ too
important and too costly to be based upon the limited data
presented ,in the Report*;;«. The information presented in the
Report is hot sufficient to prepare the final design of the
proposed hot spot project.

EPA RESPONSE 8.2

Comments relating to the cove where the Pilot Study was
carried out, differences between the cove and the Hot Spot,
and the applicability of data gathered during the Pilot
Study to the evaluation of dredging in the Hot Spot are
addressed in this reply.

The Pilot Study was designed to evaluate dredging in the
upper Estuary of New Bedford Harbor. EPA understands that
the cove and the Hot Spot are different. EPA expressed its
recognition of the difference in the following statement,
appearing on Page 5-13 of the Hot Spot FS.

"The pilot study demonstrated USAGE'S procedure for
estimating contaminant release was conservative .for the
sediment dredged during the pilot study. However,

8-3
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extrapolating the results to the Hot Spot is a big step
and should be performed with caution."

The information obtained during the Pilot Study that is
applied directly to the evaluation of dredging in the Hot
Spot is associated with the operating parameters of the
dredge, estimated production rates, and sediment
resuspension at the dredgehead.

The water depths in the Hot Spot and the physical
characteristics of the Hot Spot sediment to be dredged are
very similar to the pilot study site. A cutterhead dredge
operated as during the Pilot Study (see Table 5-2 of the Hot
Spot FS and Page 31 of the Pilot Study Interim Report) would
be expected to attain a similar production rate with similar
sediment resuspension rates in the Hot Spot.

Other characteristics of the Hot Spot and pilot study cove
are discussed below.

Hydrodynamic Characteristicsi The transport of sediment and
contamination away from the point of dredging is dependant
on the currents in the area where the work is going on.
Under normal conditions, the currents in the Hot Spot are
not strong. However, they are stronger than those in the
cove and the pattern of sediment resuspension would be
expected to be different.
4
The Engineering Feasibility Study (EFS) conducted by the
Corps of Engineers included an extensive effort to evaluate
hydraulic conditions in the upper Estuary and sediment
migration associated with dredging and disposal operations.
This effort consisted of field, laboratory and model
studies. Report 2 of the EFS describes this effort, the
results of which were used to estimate sediment and
contaminant movement away from a dredging operation in the
Hot Spot.

Contaminant Levels; PCB levels in the Hot Spot are much
higher than in the pilot study cove. Contaminant release
associated with dredging operations would be expected to be
higher than during the Pilot Study. In making contaminant
release estimates for the proposed Hot Spot dredging
operation, the Corps of Engineers used the results of an
elutriate test performed on sediment from the Hot Spot, the
sediment resuspension rate at the dredgehead determined
during the pilot study, and the estimated dredge operating
.period. The information developed in EFS Report #2 was used
to estimate the transport of contaminants away from the
point of dredging. The only information from the Pilot
Study that is directly applied in the Hot Spot estimate is
the sediment resuspension rate at the dredgehead and the

8-4
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operating characteristics of the dredge. The reasons for
directly applying this information are discussed below. The
contaminant release estimates are in Table 5-2 of the Hot
Spot FS.

Monitoring during the Pilot Study showed actual contaminant
levels adjacent to the dredgehead were less than those
predicted by the elutriate test. The Pilot Study provided
site specific data on dredge operation, contaminant release,
and sediment resuspension. The information on dredge
operation and sediment resuspension were directly applied in
contaminant release estimating procedures. Results of the
Pilot Study did not suggest that the contaminant release
estimating procedure used in the Hot Spot FS was erroneous.

The physical characteristics of sediments in the Hot Spot
Area are similar to those in the pilot study cove, as is
shown below. Thus, operating a cutterhead dredge as
recommended in the Pilot Study Report should result in
sediment resuspension rates that are approximately the same
as those observed during the pilot study.
Average Values

Hot Soot (1) Pilot Study Govern

Liquid Limit 113.3 J.19.8
Plasticity Index 46.7 50.2
Water Content 153.9 147.1
Specific Gravity 2.28 - 2.48
% Fines 58.2 75.8

(1) Based on 7 samples
(2) Based on 12 samples

Impacts; EPA estimates that contaminant release during Hot
Spot dredging will be higher than that during the Pilot
Study. However, EPA has weighed the short term increases in
contaminant levels (PCBs and metals levels) in the vicinity
of the operation during its evaluation of remedial
alternatives under the remedy selection criteria. Dredging
operations will be closely monitored to ensure that
resuspension is kept to minimum in order to minimize
significant increases in the release of contaminants to the
Lower Harbor. The design process will examine appropriate
monitoring and/or physical barriers to minimize and contain
any releases.
8-5
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8.3 POTENTIAL RELEASE OP NON-AQUEOUS PHASE LIQUIDS

DCN #31, Page 5-10

PCBs in sediments containing low levels of oils (including
the PCBs themselves) , therefore, may behave differently from
PCBs in an adsorbed or dissolved stage. An associated
release of NAPL from oily sediments upon dredging would not
be modeled or represented adequately by consideration of
suspended . sediment alone ajid extrapolating from turbidity
.......... '" .............................. -,,,,,„.,,,..,.,,,, ..
DCN 131, Page 5-28

EPA1s estimate of the flux during dredging has likely been
underestimated because it does not consider the oil phase
that has been observed in the area where dredging is
proposed.

EPA RESPONSE 8.3

The contaminant release estimates for the Hot Spot are based
on elutriate tests performed on Hot Spot sediment. While
the elutriate test does not directly address the contaminant
level in a floating sheen, it does provide site-specific
data on contaminant release. The contaminant release
estimates also include a safety factor of 2 to account for
variable conditions.

Surface floatable samples were taken in the vicinity of
sediment sampling operations in the Hot Spot. This effort
is described in EFS Report 2. The results of this sampling
indicate that the surface floatable patch or oily sheen
which forms.when the bottom is disturbed in this area can
contain high PCB concentrations. Any such releases at the
dredgehead should be taken up the suction line of the
dredge. However, other facets of the dredge operation
(raising and lowering of spuds, movement of swing cables,
workboats, etc) may result in an oily sheen on the surface.
Steps can be taken to control this sheen, such as placing an
oil boom around the operation. EPA will determine during
the design phase the appropriate method of minimizing this
particular type of potential release.

8.4 CHANGES IN ESTUARY HYDRAULICS DUB TO DREDGING

DCN #31, Page 5-12

The pilot study and the HSFS do not take into account
changes in tidal hydraulics which would be caused
8-6
-------
EPA RESPONSE 8.4

Report 2 of Engineering Feasibility Study addressed changes
in tidal hydraulics which would result from dredging in the
Upper Estuary. This evaluation indicated that removing the
surface layer of contaminated sediment (up to 2 feet) would
have minimal impact on tidal hydraulics. The majority of
the dredging will occur in the top 2 feet of sediment, with
a minimal dredging up to a depth of four feet. Refer to
Figure 7 in the Record of Decision Summary (page 44) for a
depiction of the limited extent of highly contaminated
sediment at depths greater than 2 feet.

8.5 VOLATILIZATION OP PCB8 DURING DREDGING t DISPOSAL

DCN #31, Page 5-12
^ i gnored this
pathway "compIeitieTy ';;:in. '^its -'documentiatlonF-of the proposed "hot
"" """" "" ' •""'"•'"••"••'• •••••-•••••••••••••••-—•
EPA RESPONSE 8.5

EPA has considered volatilization of PCBs during its studies
for the Hot Spot.

EPA has performed a number of studies to examine potential
volatile emissions from dredging and disposal activities.
These studies include: modeling of PCS emissions (EPA, 1987,
Thibodeaux, 1989a, and Thibodeaux, 1989b) ; bench scale
evaluations of volatile emissions from New Bedford sediment
(Brannon, 1989) ; and ambient monitoring as part of the pilot
dredging study. These documents, with the exception of the
ambient monitoring as part of the Pilot Study, are in the
Administrative Record. Section 2.4.3 of this document
states that the ambient air monitoring report will be
completed when data validation is completed. EPA has made
the supporting data from this study available to the PRPs
(see DCN #40) .

EPA will evaluate the results of the above mentioned studies
in the course of completing the pre-design studies for the
dewatering facility. The Hot Spot FS did indicate that
extensive air monitoring or controls may be required as part
of a dewatering facility.
8-7
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P.6 PILOT STUDY TOXTCTTY TESTING

DCN #31, Pages 5-15 and 16

Likewise, with the toxicity testing results, it is
impossible to evaluate the potential impacts of the
recommended alternative without the detailed results.

EPA RESPONSE 8.6

The Pilot Study's monitoring program had the following
principal objectives:

1) Gather sufficient data to address the technical
questions regarding contaminant release associated with
the dredging and disposal operations.

2) Protect the environment and regulate pilot study
operations.

The biological monitoring (toxicity testing) was conducted
to ensure that the project met the second objective. The
biological monitoring was conducted to detect impacts
associated with any and all contaminants in the water
column.

The biological monitoring tests used during the Pilot Study
were developed at EPA's Environmental Research Laboratory in
Narragansett, Rhode Island. These tests included the
measurement of contaminants in tissue of blue mussels, acute
and chronic toxicity tests developed for the Effluent
Toxicity Testing Program, and blue mussel scope of growth
tests.

Pre-operational monitoring provided data on baseline
contaminant concentrations in water, bioaccumulation of
contaminants in mussels, and biological effects on a variety
of organisms. These baseline data were used to identify
contaminant concentrations and biological responses that
were "acceptable1* compared to existing conditions.
Monitoring data collected during each operational phase of
the project were compared to the baseline information to
detect statistically significant and/or biologically
relevant changes. During the Pilot study, no statistically
significant or biologically relevant changes were detected.

The biological monitoring effort is summarized in the
Interim Pilot Study Report. Several technical papers on
this subject are currently being prepared by the EPA •
Laboratory.
8-8
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8.7 SEDIMENT RESU8PENSION DURING PILOT STUDY

DCN #31, Page 5-19

The sediment'"plume""surrounds* ther working dredge and-;:I§
obviously: being transported out:of the:cove where:;::the"
e^eriment..;.is, being; :£ond^^ed^'':":"'"''x"'''':v:''':' """"""" ""'""

DCN #32

The PRPs submitted an aerial photograph of the pilot study
operation taken on 11/25/89.

EPA RESPONSE 8.7

EPA evaluated sediment resuspension and transport during
both the Pilot Study and the Engineering Feasibility Study
(EFS). During the EPS, EPA evaluated the physical
characteristics of the sediment. EPA determined that one
sediment fraction was by far the slowest to settle and
deposit and was the easiest to resuspend (i.e., the "mobile"
fraction). This mobile fraction of the sediment comprised
28 percent of the EFS composite sample, and the percentage
of this mobile fraction in the sediment varied from 1 to 60
percent in the Upper Estuary. Coarser sediment fractions
comprised 72 percent of the EFS composite sample. Near-
field models predicted that only a small fraction ,of the
coarser sediments would move 100 meters from a dredging
operation. The model also predicted that a large fraction
of the mobile fraction suspended sediment would move beyond
100 meters of the resuspension point (i.e., dredging
operation). Based on these modeling estimates, typical
concentrations at a radius of 100 meters from the dredgehead
would be approximately 12 mg/1 above background levels,
resulting in a bulk-sediment release rate estimate of 40
g/sec. Report 2 of the EFS contains a detailed discussion
of this evaluation.

During the Pilot Study, the dredge operations were varied to
determine operating procedures which minimized resuspension
at the dredgehead. For the cutterhead dredge, operating
adjustments resulted in a sediment resuspension rate of 20
g/sec, as compared the 40 g/sec estimate discussed above.
EPA sampled monitoring stations along cross sections of the
cove during pilot study dredging operations. EPA did not
detect a well-defined plume of resuspended sediment, and
conditions returned to background levels within 500 feet of
the dredging operation.

The aerial photograph submitted by the PRPs was taken on
November 25, 1988 between 12:00 and 12:30 p.m. On this day,

8-9
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dredging operations had ceased at approximately 11:30 a.m.
so that the dredge's swing anchors could be moved while
sufficient water was available for the work boats to
operate. The plume of suspended material evident in the
photo is being generated by the work boat moving the dredge
and is not representative of a plume caused by the dredging
operation. Moving the swing anchors required the workboats
to operate at full throttle in the shallow water. The Pilot
Study recommends placing swing anchors on shore to eliminate
the need for this type of operation.

8.8 TURBIDITY MONITORING DURING PILOT STUDY

DCN 131, Page 5-20 and 5-21

Sediment resuspension in the immediate vicinity of the
working dredges was also evaluated using turbidity data
collected by Rizzo Associates personnel on two separate
occasions.,.. Turbidity monitoring conducted within
approximately 100 to 700 feet of the active dredges was
performed on December 22, 1988 and January 13, 1989 from a
small boat,The Matchbox and Cutterhead dredges were
operating during these two data collection events.
Turbidity measurements in December 1988 ranged between 5.2
and 130 NTU, and had a mean response of 34 NTU.

EPA RESPONSE 8.8

The dates the PRPs conducted monitoring (December 22, 1988
and January 13, 1989) were not days on which the dredge was
being operated in order to minimize sediment resuspension.
On December 22, 1988 the cutterhead dredge was excavating
the Confined Aquatic Disposal (CAD) cell and was removing
uncontaminated material. Operating parameters during the
movement of uncontaminated material were considerably
different from those when contaminated material was being
removed. The production rate was 75 cy/hr for
uncontaminated material as compared to 35 cy/hr for
contaminated material. A higher sediment resuspension rate
would be expected at the greater production rate. On
January 13, 1989 construction of the CAD was underway.
During this period, EPA detected higher suspended solid
levels in the cove. These higher suspended solid levels
were caused by the CAD operation and not by the dredging
operation.

The term "turbidity" represents a complex composite of
several variables that collectively influence the optical
properties of water. Attempts to correlate turbidity with
the weight concentration of suspended matter (suspended

8-10
-------
solids) are often impractical. EPA monitored total
suspended solids (TSS) during the pilot study because this
measure more accurately reflected contaminant release
directly associated with the dredging and disposal
operations. The Pilot Study showed that TSS levels in close
proximity to the dredge were elevated and diminished further
away from the operation in relation to background levels
measured outside the cove.
8.9 DREDGE PRODUCTION

DCN #31, Page 5-24

The cuttierhead: '"""dredge" resuspended contaminated sediment at
an averaged rate of 21.6 g/s, at a mean production of 20
cy/hr. . . The 35 ,cy/hr production rate represents a 75%
increase^oyerj.that attained during the pilot, study.

DCN #31, Page 5-26 - 5-27
production rate and sediment resuspensiori rate
prepared by the ACOE to evaluate the potential:; sedime|v|
resuspension rate during full scale implementation^

DCN #31, Page 5-30
«
If the government believes that a production rate of 35
cy/hr is attainable in the "hot spot" sediments, then ah
analysis and explanation supporting the increased production
rate over the pilot scale rate is required in order to
demonstrate its validity.

DCN #35, Page 8
Ih^:'geherarp::'!h in the Report do not
substantiate the conclusions reached in the Report, in
regard;/tg^:::vsedimentj.resuspension' at the dredgehead..

DCN #35, Page 14

The average of the values for resuspension rate R in this
table is^21»6, not 17.3. A plot of R versus ladder swing
speed {S). values in Table A-l is shown in Figure A-l in the
Appendix. This plot indicates no strong correlation between
S and R*

EPA RESPONSE 8.9

Various dredge operating parameters (swing speed, depth of
cut, cutterhead rotation, pump operation) influence the

8-11
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level of sediment resuspension at the dredgehead. These
operating parameters were constantly adjusted during the
early stages of dredge operation to determine a combination
which minimized-sediment resuspension. For the cutterhead
dredge, EPA computed sediment resuspension rates from 4 days
of operation which were representative of the recommended
operating procedures. (The four days of operation were Nov.
22, 23, 25 and Dec. 17, 1988.) The average resuspension
rate for these four days was 12.1 grams per second. EPA
also computed sediment resuspension rates for January 8,
1989 when the cutterhead dredgehead was rotated at full RPM,
approximately twice the speed of the other days. This
increase in rotation resulted in a higher sediment
resuspension rate, which brought the overall resuspension
average up to 21.6 grams per second. Due to the variability
in the factors which influence sediment resuspension at the
dredgehead, EPA used a resuspension rate of 20 grams per
second for the contaminant release estimates contained in
the Hot Spot FS.

Based on the Pilot Study results, EPA determined that two
passes of the dredge were necessary to reduce sediment PCB
levels to approximately 10 ppm. The cutterhead dredge
attempted to remove the top 1.5-2 feet of material in the
initial pass over an area. During the second pass, the
dredge attempted to just skim the surface and remove very
little additional material. EPA estimates the production
rate for the first pass of the cutterhead dredge to be 35
cubic yards of sediment removed per hour of dredge
operation. When the second pass is taken into account, the
production rate for a specific area decreases to 20 cubic
yards of sediment removed per hour of dredge operation. The
sediment resuspension rates determined from the pilot study
were based on sampling carried out while the top layer of
sediment was being removed, at an approximate production
rate of 35 cubic yards per hour, the same production rate
recommended in the Hot Spot FS. Several passes over an area
would be required in areas where contamination of 4,000 ppm
or greater extends below a depth of 2 feet.
8.10 POTENTIAL PROBLEM SITUATIONS PORING DREDGING

DCN #31, Page 5-32

The June 1989 ACOE report did not address the levels of PCBs
released during pilot study problem, situations and tola
potential needs to be evaluated for "hot spot11 dredging.
8-12
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EPA RESPONSE 8.10

One significant result of the Pilot Study was that problem
areas relating to dredge operation were identified.

Monitoring of ^4 harbor stations took place during the first
four days of operation for each dredge. Monitoring at an
array of stations within the pilot study cove took place
during the first three days of operation for each dredge.
These monitoring efforts involved hourly sampling at each
station during the dredge's operating period and covered
periods when operational problems were encountered. The
monitoring effort detected elevated contaminant levels on
several occasions which were related to operational
problems. These problems were associated with the matchbox
dredge's depth of cut and the placement of diffusers
placement during CAD.

8.11 POTENTIAL ENVIRONMENTAL IMPACTS DURING PILOT STUDY

DCN #31, Page 1-5

Already tfte EPA *"s pilot ''dredging 'p'rogra'mv'aT6rie7&a!p'de^
acres of wetlands a situation for which a private deyeioper
would 'be castigated and sanctioned by' ''''w'''m''"'v'''™

DCN #31, Page 1-31
^ no permits or approvals to
That program resulted
in^dre
-------
only 4 occasions when contaminant levels exceeded the
critical levels established prior to the start of
operations. These short term spikes in contaminant levels
were associated with obvious operational problems or extreme
weather events. Monitoring of the entire operational period
of the pilot study did not indicate that operations resulted
in a significant increase in the release of contaminants to
the lower harbor.

As part of the Pilot Study, EPA constructed a Confined
Disposal Facility (CDF) along the New Bedford shoreline.
EPA also dredged within a small cove in the Acushnet River
Estuary. The CDF was partially constructed below the high
water line. Approximately 700 feet of disturbed shoreline
and 50,000 square feet of subtidal area was lost. The
dredging disturbed approximately 100,000 square feet of the
estuary bottom. Both of these areas are within the confines
of the Superfund Site containing bottom sediments with
elevated levels of PCBs. No vegetation or valuable habitat
resources were lost. The appropriate state and federal
regulatory agencies participated in the planning and
approval process which led to the Pilot Study.

The Hot Spot remedial action will make use of the CDF area
for support operations. The final disposition of the CDF,
as well as that of the treated sediment, will be addressed
by the second operable unit for the Site.

8.12 PRP ACCESS TO PILOT STUDY SITE

DCN 131, Page 5-36

On behalf of the defendants Hizzo Associates formally
requested access to the Site during the pilot dredging
program to collect samples and to observe actual dredging
operations and the decision criteria process. We were
denied*.»:'

EPA RESPONSE 8.12

Representatives of the PRPs were on site observing
operations during most of the Pilot Study, beginning the CDF
construction phase and continuing through dredging
operations. PRP representatives were also allowed to sample
effluent from the CDF. The log of visitors to the Site
documents their presence and activities. The only PRP
request for Site access that the EPA denied was their
request to place an individual on the operating dredges.
EPA could not honor this request because it was not feasible
due to the limited space available on the dredges, and the
varying number of government personnel involved in

8-14
-------
monitoring the dredge. PRP representatives were allowed,
and in fact did, observe dredging operations from an
adjacent boat that operated in close proximity to the
operating dredge.
8.13 CONFINED DISPOSAL FACILITY (CD71

DCN #31, Page 1-16
. ;V* There Is no ^^^^^j^^^ai^o^f^ed by the
government and released tothe public showing that the CD|i
is"stable. Visual observation suggests that significant
subsidence and erosion has occurred, jeopardizing the
integrity;jof^ the structure,f"""'""

DCN #31, Page 5-37

The mud wave impact and Its resolutibn should be
incorporated into any design/construction discussion for
CDFs in water.,..There is no mention of the significant mud
wave problems that "developed during the construction of the
existing CDF that resulted in significant construction
delays, as well as decreased storage capacity in the cell,

DCN #31, Page 5-38
_ . ^ ^

There must be 'real and sound basis for any conclusion that
the dike is stable.*, significant re-construction must be
completed before it is used as part of a remedial action,
and there is a real question about the CDF's integrity based
on defendants observations»

DCN #35, Page 7

Possibly the fact that the CDP never attained the desired
ponding depth of 2 ft due to the excessive leakage through
the sheet pile dividing wall would explain this poorer
performarice»

DCN #35, Page 7

High polymer performance can only be expected with a
carefully designed system that provides for rapid mixing and
flocculatlon filled by settling of the coagulated solids,...
The report does not contain sufficient data or analyses to
demonstrate that the CDF,, as now constituted, can provide
adequate effluent quality for future dredging projects.
8-15
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DCN #35, Page 20

"Several concrete foundations located within the primary
cell also had a positive effect by increasing detention time
and minimizing resuspension within the cell.1* This comment
is not explained.... "The size of the secondary cell can
likely be reduced in future CDFs." No data is given to
support this statement* '

EPA RESPONSE 8.13

In-water dike construction associated with the Confined
Disposal Facility is addressed on Page 35 of the Interim
Pilot Study Report. The USAGE recommendation for in-water
dike construction is that the pilot study specifications be
followed and that modification to the specified construction
procedures used during the pilot study be avoided.

Poor foundation conditions necessitated the placement of a
high strength geotextile along the in-water dike alignment
and the construction of this section of dike in stages.
Various monitoring devices were installed to indicate when
strength gain in the underlying sediments was sufficient to
allow the second stage of dike construction to begin and
when to allow the facility to be filled with dredged
material. These monitoring devices included strain gages on
the geotextile, settlement plates, piezometers and
inclinometers. The most critical point, from the standpoint
of dike stability, was immediately after the completion of
dike construction. The CDF was filled to elevation 4-10 MLW
during late December 1988 and early January 1989, which is
the period when the design capacity of the CDF was utilized.
Currently the CDF contains dredged material to elevation
+6.0 MLW with very little water on the surface.

Since the completion of the pilot study the dike slopes on
the interior of the CDF have suffered some erosion due to
heavy rainfall events and the uniformly graded material used
on the interior dike slopes. However, this erosion has not
effected the structural integrity of the dike or resulted in
the release of dredged material or leachate to the harbor.

The CDF will have to be upgraded prior to use during Hot
Spot remediation, but upgrading the CDF will not involve a
major construction effort. Dike slopes will require
regrading and the addition of some material to bring them up
to the design cross section.

During the pilot study a polymer was added to the flow at
the weir between the primary and the secondary cells to
promote additional settling of suspended material in the

8-16
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secondary cell prior to the discharge of the water back to
the estuary. The Interim Pilot study Report describes the
procedure and the results obtained. The polymer was
selected as result of testing performed during the EFS.
These tests and the design methodology for the system. are
described in EFS Report 7.

The structures within the CDF had a positive effect on
settling. They acted as baffle dikes and prevented short
circuiting of the flow within the CDF and they broke up
currents created by the wind.
8.14 PCS REMOVAL

DCN #31, Page 5-40
The Pepbrt( page 23) states that lh
dredge left the bottom with an average of 34 ppm PCB after
ohet pass with an average cut of 1,5 feet. In Area 2 the
same dredge left the bottom with an average 10 ppm PCB after
an average cut of 1.1 feet using a second or sweep pass. No
data is presented which substantiates this statement or
Which indicates how representative this data is*

DCN #35, Page S-2

The report (page 23) states that in Area 1 the ctitterhead
dredge left the bottom with an average of 84 ppm PCB after
one pass with an average cut of 1.5 ft. In Area 2 the sane
dredge left the bottom with an average 10 ppm PCB after an
average cut of 1,1 using a second or sweep ...pass. ...A...J|p;..dat,a......is
presented which substantiate this statement. ., .The Report
(pages 46 and 47) refers to preliminary sediment sampling
and sampling for removal efficiency. It states that this
data will ; their be used; in determining the removal efficiency
of: each dredge. • If this data is not in the report, how can
dredges., are efficient in removal?
DCN #35, Page S-3

Adequate cross sections and mass balances for, solids 'and PCB
are a difficult but .a critical measurement and control
requirement for this project.,. The report neither describes
data collection procedures nor contains data substantiating
recovery of PCB-contaminated materials,

DCN #35, Page 13

Use of a second pass over the area is less productive, than a
cleanup swing as noted above. .The depth of the cutter in
the cleanup pass as well as the digging pass is

8-17
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important.... The three dredges used were able to effectively
remove the contaminated sediment while minimizing the amount
of sediment removed. The Report gives no data which
supports these statements....The Report states that sediment
PCB levels at 0.5 ft. intervals for a 3 ft. depth are
contained in Appendix 5. Appendix 5 is not in the Report.
These data, along with after dredging cores of similar
depth, are critical to the measurement of the effectiveness
of dredging in removing PCB-contaminated materials. The
spacing of the cores is not indicated. Core spacing is, of
course, * critical; aspect''of;'a. ;sampling /program,;""''''''

DCN #35, Page 21

Grid size is not a given,.. Sampling of the top 3 inches is
not adequate since this would not show any redistribution of
contaminated material into deeper portions of the bottom.
EPA RESPONSE 8.14

EPA determined that two passes of the cutterhead dredge are
required to reduce contaminant levels in the sediment. This
determination is based on sampling conducted immediately
upon completion of dredging in areas 1 and 2. Contaminant
levels in these two areas prior to dredging were similar, as
is shown below:

AVERAGE PCS LEVEL fppnO

Horizon Area 1 Area 2
0-6" 226 385
6-12" 12 34
12-18" 8 5
18-24" 4 1

The cutterhead dredge made one pass through area 1 and
removed on average 1.5 feet of sediment. The average PCB
level in the remaining sediment was 8 ppm. In area 2, the
dredge made two passes and removed on average 1.1 feet of
sediment. The average PCB level in area 2 in the remaining
sediment was less than 10 ppm. EPA determined the quantity
of sediment removed and the thickness of the sediment layer
by comparing hydrographic surveys taken prior to dredging
and immediately after dredging. EPA determined contaminant
levels by analyzing sediment cores. In area 1, 32 samples
were taken from the (125 foot by 170 foot) area and were
composited into 8 samples for analysis. The sediment
analyzed was taken from the top 3 inch horizon. In area 2,
16 samples were taken from the (60 foot by 90 foot) area and
were composited into 4 samples for analysis. The sediment
analyzed was taken from the top 3 inch horizon.

8-18
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The Interim Pilot Study Report contains a typical cross
section of the dredging areas. EPA prepared numerous cross
sections to determine the quantity of material removed.

8.15 DREDGING AND OPERATIONS

DCN #35, Page S-2

The report contains no indication that a high precision
survey system was used in the study....The report contains
no data on cutterhead depth..,. Survey procedures used in
the Pilot study are "not-'described, nor are cross section
data- pre sent ied. to confirm the "estimated, ^quantitieaii

DCN #35, Page 4
Swing Speed, Rate of advance/ Cutterhead RPM, Dredge pump,
Depth of cut... The Report does not discus what rates for
the factors in the above list comprise Standard Dredging
Procedure. We do not believe that/the Report presents
sufficient data to justify the setting of any values for the
factors listed..'..'.. General Dredging practice also does: nit
provide the appropriate approach to the work or the degree
of precision required. ' """" '"^"""

DCN #35, Page 5

The correct approach cannot be made without specially fitted
equipment and adequate procedures to assure cleanup without
excess dredging quantities.... It is interesting to observe
that no value is given for the depth of cut "when developing
plans- for ....the /Upper - Estuary,?; '"" "" :""""""

DCN #35, Page 10
Contaminant""'releasei'::"rates'"'are"related strongly to suspended
solids generation.; The data contained in the Report do notr
however,*substantiate that slow speeds result in lower'
suspended solids generation

DCN #35, Page 13

The report'""makes no mention of cutter depth while dredging
or whether cutter depth was adjusted for tide changes.... A
depth of cut of 2 ft. with a 2 ft. advance proved to be the
most effective. There are no data in the Report support
this statement.
8-19
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DCN *35, Page 14

The Report does not indicate how dredge slurry flow rates or
slurry solids concentrations were measured while
minimizing the amount of material removed. The Report
presents no data which substantiate this statement.

OCN 135, Page 21

The data contained in the Report does not demonstrate the
capability to dredge to the precision implied in the Report.
Accurate, precise surveys are critical to a project of this
--•—•-'—- —
EPA RESPONSE 8.15

Dredge Position: The Pilot Study dredging areas were
located within a cove in close proximity to the shoreline.
EPA established visual ranges on shore to define the limits
of the dredging areas. EPA used these visual ranges to
position the dredge.

Cutterhead Location: Operating the cutterhead dredge with
the dredgehead lowered two feet into the sediment was the
most effective way to minimize sediment resuspension. This
setting was used for the first pass through both areas 1 and
2. For the second pass through area 2, the cutterhead was
set at the sediment/water interface to attempt to'skim the
sediment surface to remove minimal additional material.

Hydrographic Surveys and Sediment Sampling: EPA performed
hydrographic surveys of the dredging areas on the following
dates:

September 12, 1988 Survey of areas 1 and 2. Dredging began
on November 21 in area 1.

December 15, 1988 Survey of area 1 after contaminated
sediment had been removed. Dredging was
completed on December 13.

January 6, 1989 Survey of area 1 after CAD cell had been
excavated. Dredging was completed on
January 4.

January 24, 1989 Survey of areas 1 and 2 after
contaminated sediment was removed from
area 2 and placed in area 1. Dredging
was completed on January 20.
8-20
-------
June 22, 1989 Survey of areas 1 and 2 after capping
and consolidation of CAD cell. Capping
completed on February 11.

A Corps of Engineers crew performed the surveys using a
vessel with electronic positioning equipment to establish
horizontal and vertical control.

EPA sampled dredging areas immediately after dredging on the
dates listed below. Samples analyzed were taken from the
top 3 inches of sediment after dredging.

November 30, 1988 Sampling of cutterhead work area in area
1. Dredging was completed on November
29.

December 7, 1988 Sampling of Mudcat work area in area 1.
Dredging was completed on December 6.

December 14, 1988 Sampling of Matchbox work area in area
1. Dredging was completed on December
13.

January 23, 1989 Sampling of Matchbox work area in area
2. Dredging was completed on January
13.

January 24, 1989 Sampling of cutterhead work area in area
2. Dredging completed on January 20.

Cutterhead dredge operating procedures are discussed
generally on pages 21-24 of the Interim Pilot Study Report.
Appendix 1, page 1-2 provides a more detailed discussion of
dredge operation. The following information is included in
this Appendix:

Swing Speed: Swing Speed was kept steady and as slow as
possible
Cutterhead Rotation: 50% of maximum (approximately 20 RPM)
Depth of Cut: (i.e., dredgehead location) 2 feet
Width of Cut: 60 feet
Dredge Pump: Operated at maximum RPM

EPA did not correlate swing speed to sediment resuspension.
Information from other projects indicated that with all
other factors held constant, slower swing speed resulted in
lower sediment resuspension at the dredgehead. Visual
observation of sediment resuspension during the (early
stages) of the pilot study confirmed this information. EPA
instructed the dredge operator to minimize the swing speed.
Measured swing speeds during the pilot study ranged from

. 8-21
-------
0.34 to 0.58 feet per second, with an average of 0.50 feet
per second. The dredge had the capability of attaining a
swing speed of 1.3 feet per second. Maintaining a steady
and slow swing speed is dependent on the operator's
abilities. EPA does not consider the variation in swing
speeds during the pilot study to be significant.

EPA measured the flow rate and density of the slurry
discharged into the CDF with a flowmeter and density gauge
in the pipeline prior to the discharge point.

8.16 OTHER CONTAMINANTS

DCN #31, Page 1-2

Unresolved concerns range from the resuspension of heavy
metals from the sediments into the water column*,>

DCN #31, Page 1-14

Dredging will simply aggravate the problem posed by the real
pollutants: disturbance of the harbor sediments through
dredging will resuspend metals and PAHs in the water, where
they can do the most harm.

DCN #31, Page 1-15
*
Second, as indicated above, EPA and the Corps of Engineers
have failed to properly address the problem of resuspension
of a multitude of contaminants during the dredging and
handling of sediments.

EPA RESPONSE 8.16

EPA conducted monitoring during the Pilot Study to detect
the release of heavy metals. Contaminant levels were
elevated in close proximity to the operation, but the levels
returned to background levels within approximately 500 feet
of the dredge. Monitoring did not detect the release of
metals to the Lower Harbor. The estimating procedure for
metals released during dredging is the same as that for
PCBs. Release estimates for the Hot Spot are in Table 5-2
of the Hot Spot FS. Levels of metals in pilot study cove
are similar to those in the Hot Spot.

The physical disturbances due to dredging which result in
PCB release will also release other contaminants. Operating
the dredge in the manner recommended by the Pilot Study will
minimize sediment resuspension and all contaminant release.
The dredging operations will be monitored for releases of
PCBs and other contaminants.

8-22
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EPA has not ignored other contaminants. PCB levels in the
sediment and water column far exceed those of other
contaminants.
8.17 COST ESTIMATES

DCN #35, Page S-3
rental"- rate ^tov a. •: cost ;:f or •-jthe^hot-/- spot;; or;; full -scale ......
DCN #35, Page 6

The daily' rental: rate"'"quoted""'lsv''n^t'v''partic^larly::''r^levaht'-:'as
a measure of the dredging cost of the proposed hot spot or
full scale dredging programs.... The daily rental rate?
presented in the Report for dredge, operator and attendant
plant bears little relationship to the dredging program....
Further'we have a substantial concern that a conventional
unit price/ lump sum or performance orientated contract is
appropriate for the proposed worki

EPA RESPONSE 8.17

Cost estimates for conceptual remedial actions including
dredging .were included in Report 11 of the Engineering
Feasibility Study. The Interim Pilot Study Report' did not
include any detailed cost estimates.

Detailed plans and specifications and cost estimates will be
developed during design. The Corps of Engineers design
process calls for "Value Engineering," and cost effective
options to achieve the goals of the project will be
examined. The design process also includes an assessment of
the most appropriate type of bidding for all portions of the
project.

8.18 EQUIPMENT AVAILABILITY

DCN #35, Page 5

The proposed work is so unique and cost projected by the
Report so high that a common dredge is the least important
factor in a successful job.
DCN #35, Page 12
The report describes the difficulties i "encountered
positioning anchors, their holding capabilities in the bed
8-23
-------
materials and the turbidity generated form a/»chor handling.
This issue is an example of the problems resulting from the
use of "conventional, readily available equipment11...
Placing anchors on the shore as recommended in the report
would involve the rehandling of relatively long anchor wires
as the dredge progresses and relocates itself. This long
wire would be a source of turbidity generation. We believe
that an analysis is required to demonstrate the feasibility
of,,.this •proposal*;

EPA RESPONSE 8«18

The Pilot Study evaluated three dredges, one of which was a
specialty dredge (Matchbox) designed to remove contaminated
sediments. These three dredges were selected after a
thorough review of available equipment by a team of experts.

EPA recommended an appropriately sized cutterhead dredge for
dredging in New Bedford Harbor based on its documented
performance. The cutterhead dredge is a standard piece of
equipment that is readily available from numerous
contractors.

The Interim Pilot Study Report recommended that swing
anchors be placed on shore to address the problems of
holding capability and sediment resuspension from anchor
handling. Modifications to the cutterhead dredge which
eliminate the need for swing anchors would be acceptable,
but EPA does not consider this necessary.

8.19 CONFINED AQUATIC DISPOSAL (CAD)

DCN 135, Page S-3

Five months after the placement of the CAD cap the Report
does not contain cross sections showing the cap condition.

DCN #35, Page 9

The on«;s«t of cross sections relating to the CAD
developjuint are presented in Figure 3-3 r page 3-4 of, the
Report*;p:;;These sections are not fully annotated. These
sections do not confirm that a 2 to 3 ft* cap has been
placed in the CAD.
* V..W

DCN #35, Page 21

Page 40, paragraph 4 of the Report states that "contaminated
sediment was successfully placed in a CAD cell and capped
during the Pilot Study." This statement is inconsistent

8-24
-------
with the fact that sampling work is to be done during the
second phase to determine if a cap has been successfully
placed.
EPA RESPONSE 8.19

EPA did not consider Contained Aquatic Disposal (CAD) for
the Hot Spot operable unit. The final Pilot Study report
will contain a detailed discussion of CAD, which will be
evaluated as a potential disposal method in the Feasibility
Study for the remainder of the Upper Estuary and Harbor.
###
Section 8 References
B.C. Jordan Co./Ebasco, 1989. "Hot Spot Feasibility Study,
New Bedford Harbor."

Averett, Daniel E. and Otis, Mark J., 1990. "New Bedford
Superfund Project, Acushnet River Estuary Engineering
Feasibility Study of Dredging and Dredged Material Disposal
Alternative; Reports 1-12, Technical Reports EL-88-15,
U.S. Army Corps of Engineers Waterways Experiment Station,
Vicksburg, MS.

Otis, Mark J., 1989. "New Bedford Harbor Superfund Pilot
Study: Evaluation of Dredging and Dredged Materials
Disposal," Interim Report.
8-25
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SECTION 9.0 - UNIT PROCESSES

9.1 SYSTEM INPUT RATES

9.1.1 SEDIMENT FLOW INTO THE CDF

DCN #31, Page 6-1
The report states that the USAGE recommended operating the
cutterhead dredge at a flow rate of 2,100 gallons per minute
for an operating time of 3 to 4 hours per day. At 2,100
gpm, 4 hours of pumping p«r day yields 504,000 gallons per
day. However, the process flow diagram indicates that
incoming flow rate from the dredging operation is $90,000
gallons per day, a 37 percent increase over the maximum
USAGE recommended value, This flow rate would cause
additional resuspension,

EPA RESPONSE 9.1.1

The flow rate shown on the process flow diagram in the Hot
Spot FS is incorrect. However, the calculations in the FS
are based on a dredge production rate of 35 cy/hr
recommended by the USAGE (Page 7-13 of the Hot Spot FS).

9.1.2 ESTIMATE OF SOLIDS

DCN 131, Page 6-2

The report does hot address the impact and expense of
running the system for a longer period as a result of the
dredging operation taking longer because of higher bulk
volume of dredged sediments with higher in-situ sediment
solids content.
EPA RESPONSE 9.1.2

For the purpose of the Hot Spot FS, an estimated sediment
moisture content of 50 percent by weight was used as the
basis for determining the "dry" tons of solids requiring
removal and subsequent treatment. Any variations from the
assumed moisture content of 50 percent would have minimal
impact, if any, on the length of the dredging operation.
Variables such as inclement, weather and clogging of the
dredgehead due to bottom debris would have a greater impact.
9.1.3 SOLIDS FROM PILOT STUDY

DCN #31, Page 6-3

9-1
-------
The report states that approximately 6,500 cy of material
from the pilot study is already in the CDF, However, when
the "hot spot" sediments that are placed in the CDF are
dredged out to be dewatered and incineratedr the existing
6,500 cy,/as well as the solids that have eroded from the
CDF.walls: and the existing CDF walls that will come- Into
contact.- or;/mix with dredged'', sediments^
the "hot spot" sediments. —.........

EPA RESPONSE 9.1.3

The 6,500 cy of material placed in the CDF during the pilot
study has been covered with a layer of clean dredge
material. The ultimate disposition of this material, which
has an average PCB concentration of 100 ppm, is currently
being addressed in the second operable unit FS.

Mixing of the Hot Spot sediment with the underlying material
in the CDF is expected to be minimal during discharge to the
CDF. The material placed in the CDF during the pilot study
has consolidated leaving a hard-packed surface. Discharge
of dredged Hot Spot sediment through a diffuser is not
expected to erode the structural integrity of this surface.

EPA inspected the walls of the CDF and found that erosion is
minimal and can easily be repaired.

Removal of the Hot Spot sediment from the CDF with minimal
removal of additional material underlying the Hot Spot
sediment and walls of the CDF can be facilitated by a number
of operational controls. Topographical surveying of the
current bottom elevation of the CDF can provide the means to
control the vertical cut of the dredge/excavating equipment
during removal of the Hot Spot sediment. Lining the inside
of the CDF walls with a synthetic liner would not only
minimize erosion of the CDF walls but would also serve as a
physical barrier to mixing of the CDF and Hot Spot material.

The design phase will examine the most appropriate use of
the CDF, particularly for sediment dewatering. Upgrading of
the facility, as well as the potential use of (enclosed)
tank structures, will be examined in detail during design.

9.2 SEDIMENT DEWATERING

DCN #31, Page 6-11

The conceptual design leaves several operating features for
the!sediment dewatering process undefined;

9-2
-------
o Storage of dewatered sediment prior to incineration is
not addressed;

o Required/available storage capacity;

o Control features for run-on/run-off control?

o Controls forsegregation and avoidance pfcrosa-'
contamination and air emissions/
'

o Odors and air emissions from ac^unulated sediment.

OCN 131, Page 6-13

The feas ifaility study does hot address how equipment si z ing
and operating costs for dewatering were adjusted to
accommodate dewatering from 20% to 62% solids... Additional
water content entering the incinerator has a dramatic impact
on operating cost, as that water will be evaporated.
Sensitivity of energy consumption in the incinerator to
performance of the dewatering unit should be addressed in
the feasibility study/ particularly as it relates to
incinerator performance and the operational costs*

DCN #31, Page 6-15

An extremely brief report on the dewatering pilot test was
provided. It did not appear to consider the variations in
sediment characteristics over many of the different
operating conditions that may be encountered. ' "' ™';

EPA RESPONSE 9.2

The need and available capacity for storage of dewatered
sediment prior to incineration was not explicitly addressed
in the Hot Spot FS. This operational feature will be
addressed in detail during the remedial design phase where
all problems relating to integration of batch and continuous
process flows for a range of operating conditions and
contingencies are typically resolved.

Conceptually, solutions to the problem of dewatered sediment
storage may include the following steps:

EPA could store dewatered sediment short-term in the
immediate vicinity of the incinerator. Sediment
dewatered to 50% solids would have sufficient strength
to be handled by a front end loader and piled in a
staging area. An area approximately 1,600 square feet
located between the dewatering system and the ,
incinerator could accommodate up to 5 days of dewatered
sediment;

9-3
-------
EPA coudd provide multiple dewatering units to serve as
backup 'in case of mechanical failures; and/or

EPA could remove sediment from the CDF on an
intermittent basis, with the frequency determined by
the rate-limiting step in the process train (e.g.,
dewatering or incineration).

Operational controls for run-on/run-off, segregation and
avoidance of cross-contamination, and odor emission controls
from accumulated sediment are important and will be
addressed in detail during the remedial design phase.

Conventional technologies, such as the plate and frame press
or the belt filter press, have been used successfully and
dependably to dewater a wide range of industrial and
municipal wastewater treatment facility sludges for years.
Existing performance data indicates that these technologies
can achieve a solids cake having greater than 50 percent
solids by weight (E.C. Jordan/Ebasco, 1987a). On this
basis, a bench and/or pilot scale test of dewatering was not
included in the original bench scale treatment technology
program conducted by Ebasco/E.C. Jordan. For the purpose of
evaluating a feasible remedial alternative, it was assumed
that the Hot Spot sediment could be dewatered to a 50
percent solids cake for subsequent treatment.

During the course of the bench scale program, Ebasco/E.C.
Jordan was approached by O.H. Materials, a vendor of the
recessed chamber plate and frame dewatering technology.
O.H. Materials offered to conduct a single bench scale test
of their technology to determine the dewaterability of New
Bedford Harbor sediment. The scope of services was limited
to a simple physical analysis and one test conducted on a
sample of New Bedford Harbor sediment. No chemical tests
were conducted to determine the mass balance for PCBs. This
work scope was not intended to be as rigorous as the test
protocols set forth in the bench scale treatment program
work plan (E.G. Jordan/Ebasco, 1987b) for the other
treatment technologies tested.

The results of the test conducted by O.H. Materials and
reported in their three page memorandum confirmed the
ability of conventional dewatering technologies to achieve a
dewatered solids cake (using New Bedford Harbor sediments)
in excess of 50 percent solids.

The unit cost presented in the Hot Spot FS for dewatering
New Bedford Harbor sediment was based on a 38 percent solids
influent compressed to a 62 percent solids cake. Recent
discussion with O.H. Materials indicated that the unit cost

9-4
-------
to dewater a 25 percent solids influent to a 50 percent
solids cake would be less because the final percent of cake
solids is less. The filter press on which the cost
estimates for New Bedford Harbor were based is capable of
handling an influent stream from 1 percent solids on up.
The controlling factor is the quantity and percent solids of
the cake (C. Bearden, 1989). Based on these comments, the
unit price for dewatering used in the Hot Spot FS is
conservative.

The estimate for incineration cost is developed on a per ton
basis assuming 50 percent solids in the filter cake.
Additional fuel costs associated with burning a lower solids
content feed (e.g., 45 percent) are minimal. The cost to
process an additional 10 percent of feed by volume, due to a
lower solids content, is covered by the 20 percent
contingency used in the cost estimates. The added fuel
requirement for processing one tone of 45 percent solids as
opposed to one ton of 50 percent solids is approximately 1.5
gallons of No. 2 fuel. This cost is minimal in comparison
to the overall process costs of $374/ton.

The tests performed by O.H. Materials indicated a need for
the addition of a small amount of lime (0.05 Ib/gal) to
condition the sediment for dewatering. Lime added at this
rate will increase the amount of material to be incinerated
by approximately 1.2 percent. In addition to improving
sediment dewatering characteristics, the lime wil^ have
several beneficial impacts. Lime will help to neutralize
hydrogen chloride (HCL) produced by the incineration of
chlorinated organics and will therefore help to reduce the
acid gas content of the primary combustion chamber effluent
stream. Lime will also raise the pH of the ash, which will
decrease the mobility of the residual metals. Overall,
addition of lime as a conditioning agent will have minimal
cost impact and should improve the incineration and handling
characteristics of the sediment.
9.3 INCINERATION

9.3.1 FEASIBILITY

DCN #31, Page 6-24

It is not certain what provisions are made for the
incinerator feed cake to avoid PCB volatilization, due to
atmospheric contact/ to eliminate dust problems, and to
avoid rainfall and rehydration.... Proper conveyance of "hot
spot" soils feed to the incinerator has not b««n,
demonstrated*
9-5
-------
DCN m, Page 6-25

These gases [HC1, HBr, Br2, HP] are extremely corrosive in
the scrubber systems, resulting in frequent prolonged system
shutdowns .The low fusion temperatures of alkali metal
salts lead to extreme fouling problems on ^ the heat transfer
surfaces. ..,; It is not apparent that these issues have been
considered. in the evaluation ;f .. the.;: incinerat ion,aternat:e
DCN #31, Page 6-26
generate data on sediment combustion . ch^^acitejcisjt^s^y asK
content, or potential air emissions.;

EPA RESPONSE 9.3.1

The fundamental concept of incineration is the utilization
of extreme heat to volatilize and destroy organic compounds.
An afterburner on the incineration unit is used to destroy
the volatilized contaminants. The residual ash is tested to
ensure that the material no longer meets the definition of a
hazardous waste.

Incineration has been used at several hazardous waste sites
nationwide. A transportable rotary kiln was used > at the
Nyanza Site in Ashland, Massachusetts; the Naval
Construction Battalion Center in Gulf port, Mississippi; and
the Times Beach dioxin Site in Times Beach, Missouri. Other
sites that have used incineration include: the Arco Swanson
River oil fields in the Kenai Wildlife Refuge, Kenai
Peninsula, Alaska; Tillie Lewis Food Cannery Site in
Stockton, California; the Cornhusker Army Ammunition Plant
in Grand Island, Nebraska; the Louisiana Army Ammunition
Plant in Shreveport, Louisiana.

Incineration has been demonstrated for PCB wastes ranging
from dilute aqueous streams (<1 ppm PCB) to pure PCB oil
waste streams. Incinerators can handle materials ranging
from 0 to 100 percent moisture content, 0 to 100 percent ash
content, 0 to 60 percent chlorine content, and materials
with heating values ranging from 0 to 25,000 BTU/lb. The
feasibility of incineration for the New Bedford Harbor
sediment is not in question. Specific equipment
configuration and operating parameters will be examined
during the design phase. For the purposes of the Hot Spot
FS, worst case conditions were assumed (i.e., low BTU/lb
heating value and high chlorine and moisture content),.
9-6
-------
.The incinerator systems on the market today have extensive
provisions for handling PCB contaminated materials or other
materials with high organic chlorine content. These units
are constructed of corrosion resistant materials throughout
and routinely handle materials with higher chlorine content
than is present in the Hot Spot sediment. Since there will
be no boiler components, fouling of heat transfer surfaces
will not be an issue. Additional options include enclosed
feed systems (operated under negative pressure to minimize
fugitive emissions). Since dewatered sediment will have a
cake-like consistency, conveyance should prove relatively
straight forward.

The Resource Conservation and Recovery Act (RCRA)
incineration standards, which the incinerator will be
required to follow, specify three major requirements
regarding incinerator performance:

a. The principal organic hazardous constituents
(POHCs) must be destroyed and/or removed to an
efficiency of 99.99%. POHCs are hazardous organic
substances present in the waste which are
representative of those constituents most
difficult to burn and most abundant in the waste.
The incinerator's performance in treating POHCs is
considered indicative of overall performance in
treating other wastes.
«
b. The particulate emissions must not exceed 180
milligrams per dry standard cubic meter, corrected to
7% oxygen in the stack gas. Compliance with the
performance standard for control of particulate
emissions is documented by measuring the particulate
load in the stack gas during the trial burn.

c. Gaseous hydrogen chloride (HCL) emissions must be
reduced either to 1.8 kilograms per hour or at a
removal efficiency of 99%. Compliance with the
performance standard for control of gaseous HCL
emission is documented during the trial burn by
measuring HCL in the stack gas.

There will also be requirements for waste analysis (before
and after treatment), operation of the incinerator,
monitoring, and inspections. Additionally, the incinerator
will be required to comply with any additional provisions
under the Toxic Substances Control Act (e.g., 99.9999%
destruction removal efficiency).

Two published technical articles on incineration of .
contaminated soils describe the results of process and
emissions sampling and analysis.

9-7
-------
a. The first article, "Incineration of a Chemically
Contaminated Synthetic Soil Matrix Using a Pilot-Scale
Rotary Kiln System," describes the results of two tests
conducted on soils containing a range of concentrations
of contaminants typical of those found at Superfund
sites. A complete series of pilot-scale test burns
was conducted and a battery of process and emission
samples were collected and analyzed. The results from
two tests indicate that the ash (treated soil) produced
by incineration met proposed regulatory limits for all
organics and metals, whereas the untreated soil
exceeded the regulatory limits for organics.

b. The second article, "ENSCO MWP-2000 Transportable
Incinerator," describes the results of several tests
using three full-scale mobile rotary kiln incinerators.
The first trial burns were compliance tests for a State
of Florida air permit. The kiln was tested at a feed
rate of 9,600 pounds per hour of solids over a wide
range of operating conditions. Combustion efficiency
was consistently above 99.9%, and particulate emission
levels were less than one-half of the regulatory (RCRA)
standard. The second set of three trial burns included
PCB-contaminated soils and liquid PCBs. Destruction
and removal efficiencies (DREs) were consistently
higher than the Toxic Substances Control Act (TSCA)
requirement of 99.9999%. Particulate loading was
approximately one-quarter to one-half of the'RCRA
standard. The third set of trial burns was conducted
at a site in Mississippi with dioxin-contaminated soil.
The dioxin surrogates hexachloroethane and
trichlorobenzene showed DREs greater than 99.9999%, the
RCRA standard for dioxin. The particulate emission
levels were less than one-half the RCRA standard.

Incineration of municipal solid waste (MSW) is a different
process than high temperature incineration of soils or
sediment. Although dioxins are sometimes generated in low
levels by MSW incinerators, dioxins have not generally been
reported from testing of hazardous waste and PCB
incinerators. There are several reasons why dioxins are not
usually detected in hazardous waste incinerators, such as
the one that has been selected in this remedy for the Hot
Spot sediment.

a. Hazardous waste incinerators are designed to
optimize mixing of the waste material with
combustion air. Oxygen is required to destroy
organics. When sufficient oxygen is not
available, organics may only be partially
destroyed, resulting in emissions of compounds

9-8
-------
such as dioxins. Hazardous waste' incinerators are
operated with excess oxygen and are designed to
maximize the mixing of oxygen with the waste
gases. This design ensures efficient combustion
and reduces the likelihood that dioxins will be
generated.

b. Hazardous waste incinerators are designed with
long gaseous residence times. When compounds are
volatilized (evaporated) from the soil, the
resulting gas is mixed with oxygen at high
temperatures to oxidize the organics. Hazardous
waste incinerators are designed to have at least
two seconds of mixing time for the gases at
extremely high temperatures. This residence time
is sufficient to minimize the amount of
uncombusted organics released in the incinerator
emissions.

c. Hazardous waste incinerators are designed to
operate at high temperatures. In addition to the
long residence times for the gases, incinerators
are also designed to operate at high temperatures
in the primary combustion zone. Gases are exposed
to temperatures in excess of 2,000 degrees
fahrenheit for two seconds in PCB incinerators.
These high temperatures, combined with good mixing
and sufficient residence time in the primary.
combustion chamber, destroy any organics in the
incinerator emissions. The sophisticated design
considerations employed for hazardous waste
incinerators minimize the possibility of emissions
not meeting all of the regulatory standards.

Test burn results and final plans and specifications
developed during the design phase, as well as results of
sampling during actual incinerator operation, are public
information. EPA will share this information with the
public as it becomes available. EPA will provide this
information to the local information repository, as well as
present the findings to the Community Work Group, which has
been the major vehicle for community involvement over the
past several years.

EPA is aware of the desirability of minimizing impacts, such
as noise, from remedial activities. However, a certain
degree of disruption is unavoidable with any construction
activities. The design process will attempt to minimize any
short term disruptive impacts.
•
Once the design process is completed, the contract for
conducting the sediment dredging and incineration will go

9-9
-------
out for bid. Once all of the bids are evaluated, the
contract will be awarded. The contractor that has been
awarded the contract will bring an incinerator on-site to
treat the contaminated Hot Spot sediments. The contractor
will be required to conduct a "trial burn" on-site to
confirm that the equipment is capable of meeting the --
performance standard of decontaminating the sediments and
meeting all air pollution control requirements. Only after
the contractor has demonstrated that it is capable of
meeting all performance standards and control requirements
will the contractor be given approval to proceed with
incinerating the (remaining) Hot Spot sediments.

9.3.2 SCRUBBER WATER DISCHARGE

DCN #31, Page 6-10

The fly ash solids will contain heavy metal(BV-:-ffletaTroxIdes
and hydroxides. There has been no testing of fly- aislhi
characteristics, leaching potential for metals, and of
effective"water treatment for removal;ofmetalsTpri|*§£o
discharge.;

EPA RESPONSE 9.3.2

During the design phase, EPA will conduct testing on the
treated sediment (i.e., fly ash solids) to determine the
levels of metals remaining in the ash and their
leachability. EPA will conduct the Toxicity Characteristic
Leaching Procedure (TCLP) test on the ash generated during
the test burn to determine the need for solidification. See
Section 9.3.4 below for further discussion of ash
solidification.

The scrubber water from the incinerator will be treated
using a lime or caustic additive. The addition of a basic
(i.e., opposite of acidic) material serves to neutralize the
chlorine in solution and also tends to precipitate metals.
(Most metals have minimum solubility at a pH of 8.5 to
11.0.) The neutralized scrubber water will be temporarily
held in a storage tank to allow settling of precipitated
solids and will be reused. Solids removed from the tank
could be mixed with the CDF sediments or solidified
separately. Since these solids will have a high pH, they
will readily solidify. The lime used to neutralize the
scrubber water would have beneficial effects on
solidification and would reduce the need to condition the
sediments prior to dewatering.
9-10
-------
9.3.3 AIR POLLUTION CONTROL

DCN #31, Page 6-28

There has been no testing of fly ash or air emissions to
develop test data for selection of the air emission control
system. The effect of volatile toxic metal emissions on
ambient air quality should be evaluated. Chemicals will be
required for scrubbing towers or venturi scrubbers as
considered in the FS. Chemical storage is not completely
addressed in the report from operational or contingency
point* 6fyiw* Handling of fly ash from dry precipitators
or baghouses is not described in any details

EPA RESPONSE 9.3.3

Equipment used for air pollution control is designed to
achieve a high level of particulate, acid gas, and volatile
metals removal. Typical values are less than 0.08
grains/dscf of particulate (required by regulations);
greater than 99 percent acid gas removal; and greater than
99 percent volatile metals removal (for lead and arsenic).
The specific type of equipment to achieve these levels will
be specified in the design phase, examined during the test
burn, and verified during the trial burn.

Solids collected in the scrubber and the particulate control
devices are referred to as fly ash. Fly ash will be handled
with the rest of the solid effluent. It will stored or
solidified, if necessary. Handling characteristics are
similar to those of the treated sediment.
9.3.4 SOLIDIFICATION OF ASH

DCN #31, Page 6-29

The disposal of the ash is a critical element of the overall
treatment,system and the disposition of the filial end
product should be reconciled prior to the recommendation and
d<^i9M^£M;:M(l?ra11 remedial action system.

EPA RESPONSE 9.3.4

There has been no testing conducted to verify the
performance of solidification on incinerator ash from
treating the Hot Spot sediments. However, solidification
has been demonstrated as an effective treatment for a wide
variety of metals in a variety of matrices. The incinerated
sediment from New Bedford Harbor is expected to provide a
good homogeneous matrix for the subsequent handling and

9-11
-------
treatment of residual metals. Bench- and/or pilot-scale
tests will be conducted on incinerated New Bedford Harbor
sediments during the design phase to select and confirm the
performance of solidification agents for immobilizing metals
in the ash residue.

A major reason for conducting the test burn on the
contaminated sediments is to characterize the incinerator
ash, as well as to specify the appropriate combination of
emissions controls. Since the contaminated sediments
contain elevated levels of metals which are not destroyed by
the incineration process, extensive sampling will be
conducted to determine the levels of contaminants and how
they behave both before and after treatment. If the treated
material fails the TCLP leaching test (used to determine
whether or not a material is considered to be a hazardous
waste under RCRA), additional treatment (i.e.,
solidification) will be required for the treated sediment.

EPA assumes that the treated sediment will be considered a
hazardous waste under RCRA, due to the level of metals
present. This assumption will be verified by the test burn
results, as well as by confirmatory sampling that will be
required as the incineration process proceeds. The sediment
that is dredged for treatment will be solidified and stored
temporarily, and its ultimate disposition will be addressed
in the second operable unit for the Site.

9.4 COST ESTIMATES

DCN #31, Page 6-30

The following; is a partial list of Items for which it is not
clear that: costs were included in the HSFS estimate or for
which the cost analysis was incomplete for the incineration
alternative:
Screening of oversized solids before
mechanical dewatejringjf

Excess capacity in solids filters to handle
upsets and variable performance in the CDF;

Chemical storage facilities and operating
costs for chemical addition; * T«»

Operating expense to dewater and process
sludge from water treatment system;
i
Adequate quantity of activated carbon in the
water treatment system for removal of PCBs;

9-12
-------
Equipment and operating expenses for removal
of solids from CDF primary and secondary
cells;

Cost estimates for secondary deva taring arid
handling of dewatered sediments for the 6,500
cubic yards of solids already in the CDF f row
pilot operations? """" ................................... ,,,,,,,,,,,,,,,,,,,, ......

Adequate processing capacity in mechanical
dewatering to handle incoming sludge at 15 to
20 percent solids;

Increased operating expense for longer- cycle
times to process sludge quantity based on
limitation 'of; water .flux rate;;:'

Storage facilities for dewatered sludge
including controls for runoff, leachate,
odors and fugitive emissions ?
incineration of
dewatered sediments for the 6, 500 cubic yards
of solids already in the CDF from pilot
operations?

o Incineration system sizing to accommodate
.,„, "additional noiature content in dewatered
solids and maintain design processing! rate
_ fff, f~ -sWV '••*. f ftt f'ff -MlWwJv ff >
for dry solids?
s*. s f *s ftffr AV f $

o Fuel delivery and storage faciliti«s>

o Allowance for additional fuel if dewatering
"does not achieve 50% solids and contingency
for market fluctuations in pricing;

o Cost estimates for solidification of
incinerator ash for the 6,500 cubic yards of
solids already in the CDF from pil ~
operations t
cost of the formulation that wold
actually be utilized for the solidification
of incinerator ash;

Disposal of fly ash as hazardous waste if
solidification cannot meet treatment
-------
Greater quantity of solids for processing
through the CDF, dewatering, incineration and
solidification because of low estimate of in-
situ sediment moisture content?
DCN #31, Page 6-35
estimate, used a series of
optimistic assumptions relative to the systea
chariactiBrlitics;:': and:; operating parameter values... » A
realisjtic sens itiyity analysis and cost analysis of the
system has;: hot been prepared* As a result r _ the estimated
cost of implementation is significantly underestimated and
DCN #31, Page 6-38
: beeW'listedTf oT7wliicn the potential
costs have not been : evaluated in the HSPS. When these
potential impacts on the cost are combined and the impacts
compounded .through the recommended system, it ia
demonstrated that the potential cost of the system could
exceed $30 or $40 million.
EPA RESPONSE 9.4

EPA CERCIA RI/FS guidance prescribes that cost estimates for
remedial alternative evaluation consider direct capital
costs (e.g., equipment, labor, and materials necessary to
implement the alternative), indirect capital costs (e.g.,
engineering, legal and licensing, contingencies), and annual
costs (e.g., post-construction operation and maintenance).
Furthermore, these cost estimates are expected to be
accurate within +50 percent to -30 percent.

For the purposes of an FS, only the major components of a
remedial alternative are identified for cost estimation.
Costs associated with specific items such as: screening of
oversized solids prior to mechanical dewatering; increase
operating expense for longer cycle times to process sludge;
and actual solidification formulation [for immobilizing
metals]; and utilities and services such as city water
storage, employee lunch room/washrooms, will all be
addressed in the design phase.

In assessing cost sensitivity, the contribution of each
major component to the total cost of a remedial alternative
is considered. For example, sediment dewatering and water
treatment collectively account for 11.3 percent of the'total

9-14
-------
cost of the incineration alternative. Therefore, wide
variations in the specific assumptions used to estimate
these costs would not substantially impact the overall
remedial cost.

Incineration accounts for 39.8 percent of the overall
remedial cost. The unit price of $374/ton is based on
information collected from other full scale incinerator
applications. In general, costs for these other
applications included excavation and disposal of the ash.
The cost estimate for incineration used in the Hot Spot FS
includes the following specific items: feed system,
monitoring systems, health and safety program, laboratory
and office facilities, [incinerator] control systems, air
pollution control systems, ash handling, fuel storage and
handling, feed storage area, electrical subsystems, and
scrubber water handling and treatment.
**#
Section 9 References;

Bearden, Charles. 1989. Personal communications between
Charles Bearden, O.H. Materials, and Roger Hathaway, E.C.
Jordan, November 22, 1989.

E.C. Jordan Co./Ebasco, 1987a. "Detailed Analysis of
Remedial Technologies for the New Bedford Harbor Feasibility
Study;" prepared by E.C. Jordan Co. for EPA.

E.C. Jordan Co./Ebasco, 1987b. "Request for Proposals for
Bench Testing of Selected Technologies for PCB
Destruction/Detoxification: New Bedford Harbor Feasibility
Study;" prepared by E.C. Jordan Co. for EPA.

Esposito, M.P. et al., "Incineration of a Chemically
Contaminated Synthetic Soil Matrix Using a Pilot-Scale
Rotary Kiln System;" U.S. EPA Risk Reduction Laboratory,
Cincinnati, Ohio.

Lanier, John H. "ENSCO MWP-2000 Transportable Incinerator;"
Environmental Systems Co., Little Rock, Arkansas.
9-15
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SECTION 10.0 - EVALUATION OF ALTERNATIVE TREATMENT TECHNOLOGIES

10 . 1 ALTERNATIVE TECHNOLOGIES

DCN #31, Page 7-11, Section 7.7.4

Numerous technologies considered for implementation and some
that were pilot or bench-scale tested, such as alkali metal
dechlorination, were eliminated from consideration due to
lack of historical implementation or full-scale pilot
testing, This is contrary to ,EPAfs own policy of technology
innovation and the law, relied on by tne Agency to support
cleanups at a number of other, Massachusetts Super fund sites.
A decision to" eliminate these alternatives should have been
made before the bench and pilot tests since the criteria for
their elimination was not related to the results of the
tests. New Bedford Harbor should not have been utilized by
the government for experimentation with technologies, after
the agency excluded them from review, since this was Costly
and unrelated to New Bedford Harbor cleanup*

DCN #31, Page 7-12, Section 7.7.9
ifi-^^ dismissed out of
hand without any serious consideration of their potential
...... """'"""" ............ """"""" ....... .......... """"" ............. """"
DCN #31, Page 7-23, Section 7.9.26

The overview of the bench-scale technology test, program
discusses the five technologies that were bench-tested:

o Inrfiitk "vitrification
o KPEG
o dewatering
o biodegradaticn
o B.E*S«T. solvent extraction

This report states that test were used to determine "the
effectiveness and potential material handling problems and
to define the^cbsts 'estimates for each method. In reviewing
this dpcjroent with other EPA documents, ,it Is apparent that
KPEG, biodegradation and
were *pi?; Eliminated for reasons that could have been or were
identified prior >to the initiation of the bench-scale test.
Therefore, these tests did not provide any data that either
verified the feasibility and applicability of the technology
for New Bedford Harbor or helped to refine the cost ^
estimates*- -
10-1
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EPA RESPONSE 10.1

Remedial alternatives consist of combinations of technology
types and process options that form a series of response
actions necessary to achieve the remedial objectives
developed for a site problem. The Superfund Amendments
(SARA) direct EPA to select a remedial action that utilizes
permanent solutions and alternative treatment technologies
or resource technologies to the maximum extent practicable.

EPA identified, screened, and evaluated treatment
technologies for New Bedford Harbor in accordance with SARA
requirements and CERCLA RI/FS Guidelines. The methodology
and results of this work are described in detail in numerous
published reports (E.G. Jordan Co./Ebasco, 1987a,b,c;
1989a,b).

EPA identified sixty sediment and water treatment process
options in the five major technology types identified for
New Bedford Harbor: physical, chemical, thermal, biological,
and in situ treatment (Table 5-1, E.G. Jordan/Ebasco,
1989a). EPA screened these technologies with respect to
their applicability to treating PCBs and/or metals in
sediment and/or water matrices, and whether they were
technically implementable. As a result of this screening
step, the initial list of sixty treatment technologies was
reduced to eleven (Figure 5-2, E.G. Jordan Co./Ebasco,
1989a).

EPA conducted an evaluation of the remaining eleven
treatment technologies to assess the effectiveness, the
level of development (i.e., the readiness of the technology
for full-scale implementation at the anticipated time of
completion for the New Bedford Harbor FS), and to obtain
refined cost estimates of these treatment technologies for
the site and waste specific conditions present at New
Bedford Harbor. EPA uses available data and information
coupled with best engineering judgement to determine the
effectiveness, implementation, and cost in its detailed
evaluation of technologies for a CERCLA FS. Available
information and performance data for many of these
technologies looked promising for New Bedford given the site
and/or waste specific characteristics found there. However,
much of this information and data was generated from earlier
stages of technology development and did not necessarily
reflect advances in process development which had occurred
at the time these technologies were being evaluated for New
Bedford.

Therefore, EPA conducted the bench-scale treatment program
to ensure that any remedial alternatives incorporating
treatment technologies reflected state-of-the-art

10-2
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' information and information date specific to New Bedford
Harbor. The results of this test program were used to
determine:

the effectiveness of the treatment technologies on
treating PCB and metal contaminated sediment and water
from New Bedford Harbor;

potential material handling problems and process rate
limiting features that might develop during scale up of
the technology at New Bedford Harbor;

refined cost estimates for treating New Bedford Harbor
sediment.

Four of the eleven treatment technologies were selected for
the bench-scale test program: in situ vitrification, the
KPEG process (alkali metal dechlorination) , advanced
(aerobic) biodegradation, and the B.E.S.T. process (solvent
extraction) . Details on the selection of these technologies
are reported in E.G. Jordan/Ebasco, 1989b. A fifth
treatment technology, dewatering, was included in the
program under a different arrangement described in Section 9
of this Responsiveness Summary.

The results of this bench test program and how they were
used in the Hot Spot FS are reported in detail E.G.
Jordan/Ebasco, 1989a,b.

10.2 SOLVENT EXTRACTION fB.E.S.T. PROCESS)

10.2.1 TOXICITY OF TEA

DCN #31, Page 7-13, Section 7.7.13

The. B.E.S.T, extraction solvent r TEA is toxic by ingestion
and inhalation and has caused liver and kidney damage In
exposed animals. The solvent could have adverse health
effects on workers* These facts were arbitrarily excluded
j^ t " ''*^WWgWVI*'*^''^ ' "* V.W
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amines and to ammonia. The Occupational Safety and Health
Administration's (OSHA) permissible exposure limit and time
weighted average (PEL/TWA) is 25 ppm, two orders of
magnitude higher than the level at which TEA is detected by
smell.

Toxicity studies have been conducted with TEA on laboratory
rats by the National Institute for Occupational Safety and
Health in Cincinnati, Ohio. No adverse effects were
observed in rats exposed to 250 ppm TEA vapor for six hours
per day, five days per week, for six months. When TEA
levels were raised to 1,000 ppm for six hours per day for
ten days, the rats showed damage to mucous membranes in
nasal passages, trachea and lungs. Other laboratory
experiments testing the effects of TEA inhalation have shown
an LCLo (lowest published lethal concentration) of 1000 ppm
for four hours for both guinea pigs and rats (Sax and Lewis,
1984) .

Comparison of the threshold for smell, the PEL/TWA, and the
laboratory experimental data indicates that fugitive TEA
emissions would become noticeable to workers long before
permissible exposure or health threatening levels had been
reached.

Laboratory experiments testing the effects of ingestion of
TEA have shown L050 (lethal dose 50% kill) values of 460
mg/kg (body weight) and 546 mg/kg for the rat and jnouse,
respectively (Sax and Lewis, 1984). This rate indicates
that a significant quantity of pure TEA would have to be
ingested by an average 70 kg adult to be life-threatening.

In practical terms, the B.E.S.T. system is designed to
operate as a closed system such that no TEA is released into
the air as air emissions or becomes available for direct
contact with equipment operators. In addition, operators
and maintenance personnel would receive extensive training
on the safety related aspects of handling TEA and the
potential health impacts of TEA exposure. Minimum
protective equipment consisting of boots, overalls, hard
hats and goggles that would be worn by all personnel when
working on the site within the BEST unit perimeter.
Personnel actually working on the unit could be required to
wear breathing protection as an additional safeguard against
possible fugitive releases of TEA.

Finally, EPA did not select the B.E.S.T. technology for this
operable unit*
10-4
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10.2.2 PILOT TESTING OF NEW PROCESS HARDWARE

DCN #31, Page 7-13, Section 7.7.15

Although,the RCC B.E.S.T. process has operated at a
demonstration scale at a Savannah:, Georgia superfund
its operation and extraction efficiency using the new
washer-drier equipment has not been proven at either the
pilot or commercial scale..,* Similarly, it is not clear
that the solids handling problems are minimized using the
washer-drier equipment because the time required for
settling'the fine particles from the harbor sediments could
be quite long,"necessitating numerous washer-driers to
achieve,the required capacity*

DCN #31, Page 7-14, Section 7.7.16

Many of the'problems noted in the CF Systems tests using
liquid propane should be anticipated with the RCC B.E.S.T-
process. This is particularly true since the B.E.S.T.
evaluation was only done at the bench scale and problems'
specific to the harbor sediment such as solids handling,
solids carryover and PCB accumulation would not have been
observed except in the pilot plant or commercial scale
operation....

EPA RESPONSE 10.2.2

Resources Conservation Company's (RCC) B.E.S.T. extraction
process using triethylamine (TEA) solvent has been
successfully demonstrated on a pilot-scale at a Savannah,
Georgia superfund site. This demonstration utilized RCC's
prototype 100-ton-per-day multistage treatment unit. RCC's
bench test protocols, which were used to evaluate the
treatability of New Bedford Harbor sediment, were developed
to simulate the process dynamics of their prototype unit.

Currently, RCC is pilot-testing a different process hardware
system using Littleford rotary washer-dryer units. These
units are readily available and are used extensively in the
chemical processing industry. One major advantage of this
processing system is that sediment-solvent mixing is more
uniform, thereby increasing the extraction efficiency per
stage (or wash cycle). In addition, the sediment is not
moved from one reaction stage to the next (as it was in the
prototype system) which simplifies material handling.

Within the last month, RCC has completed a pilot-scale
demonstration of their new process hardware system at a
Superfund site in Greenville, Ohio. A ten gallon Littleford
unit was used to treat PCB contaminated soils. This ten
gallon unit is the same unit used by Littleford to pilot-

10-5
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test operational and design parameters prior to full scale
implementation. The results of RCC's tests at the
Greenville site indicated that soils contaminated with 150
ppm PCBs were reduced to less than 5 ppm PCBs using the new
process system (Weimer, 1989).

Application of this new process system at New Bedford Harbor
would require additional pilot-scale tests to develop
operating and design data for configuring a B.E.S.T.
treatment unit for treating New Bedford Harbor sediments.

As noted in EPA Response 10.2.1, EPA did not select the
B.E.S.T. technology for this operable unit. Doubts as to
the (full-scale) reliability for the heavily contaminated
Hot Spot sediments contributed to EPA's selection of
incineration over solvent extraction.
Section 10 References;

E.G. Jordan Co./Ebasco, 1987a. "Initial Screening of Non-
removal and Removal Technologies for the New Bedford Harbor
Feasibility Study;" prepared by E.G. Jordan Co. for EPA.

E.G. Jordan Co./Ebasco, 1987b. "Initial Screening of
Detoxification/Destruction Technologies for the Ne,w Bedford
Harbor Feasibility Study;" prepared by E.G. Jordan Co. for
EPA.

E.G. Jordan Co./Ebasco, 1987c. "Detailed Analysis of
Technologies for the New Bedford Harbor Feasibility Study;"
prepared by E.G. Jordan Co. for EPA.

E.G. Jordan Co./Ebasco, 1989a. "Hot Spot Feasibility Study
for New Bedford Harbor;" prepared by E.G. Jordan Co. for
EPA.

E.G. Jordan Co./Ebasco, 1989b. "Overview of the Bench-
Scale Treatment Technology Test Program for the New Bedford
Harbor Feasibility Study;" prepared by E.G. Jordan Co. for
EPA.

Sax, Irving N., and Richard Lewis, Sr. Dangerous Properties
of Industrial Materials. Seventh Edition, Volume III. (Van
Nostrand Reinhold, New York). 1984.

Weimer, L., 1989. Personal communications between L.
Weimer, RCC, and Douglas Allen, E.G. Jordan. December 5,
1989.
10-6
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ATTACHMENT A
CHRONOLOGY OF COMMUNITY RELATIONS ACTIVITIES
CONDUCTED AT THE NEW BEDFORD HARBOR SUPERFUND SITE

Fall 1982 - EPA prepared a Community Relations Plan based on
interviews with local officials and residents.

December 8, 1982 - Public meeting held to explain Superfund
process. Speakers from EPA, DEQE and MA Department of
Public Health.

February 9, 1983 - EPA distributed copies of the Remedial
Action Master Plan (RAMP) report to the New Bedford Site
mailing list.

February 14, 1983 - EPA held a 30-day public comment period
on the RAMP concluding on March 14, 1983.

May 18, 1983 - EPA held a public meeting to update residents
about harbor investigation activities.

December 20, 1983 - EPA distributed an information fact
sheet and update to the site mailing list describing studies
to be performed.

February 1984 - EPA began distributing monthly progress
reports in English and Portuguese to the site mailing list.
These reports were sent every month through October 1984.

March 8, 1984 - EPA held a public meeting to update the
public on site cleanup activities.

June 18, 1984 - EPA held a public informational meeting on
environmental issues in Southeastern Massachusetts.

June 1984 - EPA distributed pamphlets to public and private
schools in New Bedford, Acushnet, and Fairhaven describing
PCBs and areas to avoid to prevent exposure to contaminants
in the New Bedford harbor area.

July 18, 1984 - EPA distributed a copy of the Remedial
Action Master Plan (RAMP) Responsiveness Summary to the site
mailing list.

July 27, 1984 - EPA issued a press release stating that EPA
would post warning signs in the harbor area.

August 8, 1984 - EPA issued a press release announcing that
a public meeting would be held September 7 to discuss
contamination and cleanup plans for the estuary.
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August 22, 1984 - EPA held a public meeting to explain Hot
Spot cleanup options.

August 23, 1984 - EPA began a public comment period
concluding on January 15, 1985 to provide an opportunity for
public comment on Hot Spot cleanup options.

August 1984 - EPA conducted interviews with leaders of the
Portuguese community to determine how better to inform and
involve the Portuguese community. Copies of a Portuguese
version of the PCB pamphlet distributed.

September 7, 1984 - EPA held a public meeting to discuss
cleanup plans for the estuary. THe meeting was held at the
Portuguese community center and translated into Portuguese.

September 12, 1984 - EPA held an open house to explain
cleanup options for the Estuary.

September 27, 1984 - EPA issued a press release announcing a
public hearing on October 25 and a public comment period on
Hot Spot cleanup options.

October 1984 - EPA distributed a mailing in Portuguese
explaining cleanup options and opportunities for public
comment.

October 25, 1984 - EPA held a public hearing on cleanup
options.

October 4, 1985 - EPA issued a press release announcing a
public meeting on October 17 to explain the Focused
Feasibility Study (FFS).

October 17, 1985 - EPA held a public meeting to explain the
FFS.

October 28, 1985 - EPA issued a press release announcing the
authorization of funds to conduct the Pilot Study (FFS) at
the New Bedford Harbor Site.

September 17, 1986 - EPA issued a press release announcing
the distribution and availability of a project management
plan for remedial activities at the site.

April 13, 1987 - EPA issued a press release announcing a
public meeting on April 30 to discuss studies underway for
the estuary and harbor, including the risk assessment.
i
October 1987 - New Bedford Community Work Group (CWG) formed
to participate in harbor cleanup decisions, monitor the
remedial process and site investigations, and represent
community concerns to federal and state agencies addressing
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harbor clea'nup. The CWG has been meeting regularly since it
was formed. EPA and DEP representatives regularly attend
CWG meetings and provide status reports and presentations on
harbor studies. ~ ~

April 7, 1988 - EPA conducted a public groundbreaking
ceremony to announce the beginning of construction of the
Confined Disposal Facility (CDF).

August 26, 1988 - EPA conducted a field trip to the Site to
provide an opportunity for members of the public to learn
about the Superfund Innovative Technology Evaluation (SITE)
demonstration program.

November 22, 1988 - EPA issued a press release announcing
that the CWG was awarded a $50,000 Technical Assistance
Grant (TAG) from the EPA.

November 29, 1988 - EPA issued a press release announcing
two (2) open houses on December 2 and 3 to view pilot study
dredging and disposal activities.

July 28, 1989 - EPA issued a press release announcing that
an August 3 public meeting would be held to present Hot Spot
cleanup options. The release also announced that a public
comment period would take place from August 4 through
September 1, 1989.
4
August 3, 1989 - EPA held a public meeting on the FS and
Proposed Plan for the Hot Spot Study Area.

August 16, 1989 - EPA held a public hearing on the FS and
Proposed Plan for the Hot Spot Study Area.

August 17, 1989 - EPA issued a press release announcing that
an additional public hearing would be held on August 22 and
the public comment period on Hot Spot cleanup options would
be extended through October 2, 1989.

August 22, 1989 - EPA held an additional public hearing to
hear PRP cleanup options to address harbor contamination.

September 25, 1989 - EPA held an additional public hearing
to hear questions from the CWG and general public regarding
Hot Spot cleanup options..

October 2, 1989 - EPA issued a press release announcing the
extension of the public comment period through October 16,
1989.
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ATTACHMENT B
PUBLIC HEARING TRANSCRIPTS:

AUGUST 16, 1989

AUGUST 22, 1989

SEPTEMBER 25, 1989
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