SDMS DocID 251753

SCOPE OF WORK TECHNICAL IMPRACTIBILITY (TI) EVALUATION

AND FIELD WORK FOR HYDRAULIC

CONTAINMENT SYSTEM DESIGN

HOWS CORNER SUPERFUND SITE PLYMOUTH MAINE

SEPTEMBER 2003

Prepared by

WOODARDampCURRAN Engineering bull Science bull Operations

WOODARD amp CURRAN INC 41 Hutchins Drive Portland ME 04102 (207)774-2112

CORPORATE OFFICES Maine Massachusetts N e w Hampshire Connecticut Florida

Engineering bull Science bull Operations operational offices throughout the us

October 10 2003

William P Lovely Jr Remedial Project Manager USEPA - New England Region 1 Congress Street Suite 1100 (HBT) Boston MA 02114-2023

Subject Hows Corner Superfund Site Plymouth Maine Transmittal of Scope of Work - Technical Impracticability Evaluation and Field Work for Hydraulic Containment System Design

Dear Bill

Three copies of the Final Scope of Work (SOW) for Technical Impracticability Evaluation and Field Work for Hydraulic Containment System Design are enclosed Three paper copies of the report are also being provided to MEDEP today

Please contact me at 1-800-426-4262 if you have any questions about the enclosed SOW Bill we appreciate your continued efforts in working with us to bring this project to a successful completion

Sincerely

WOODARD amp CURRAN INC

n^f

Thomas R Eschner Senior Project Manager

Enclosures

cc Claudia B Sait MEDEP (3 copies) David P Littell Pierce Atwood (1 copy) Jim Rawson General Electric (1 copy) Kristin Larson Skadded Arps Slate Meather amp Flom (1 copy)

41 Hutchins Drive i Portland Maine 04102 i 207-774-2112 i 207-774-6635 (Fax) i 1-800-426-4262 i wwwwoodardcurrancom

CORPORATE OFFICES Maine Massachusetts N e w Hampshire Connecticut Florida

Engineering bull Science bull Operations operational offices throughout the us

October 10 2003

William P Lovely Jr Remedial Project Manager USEPA - New England Region 1 Congress Street Suite 1100 (HBT) Boston MA 02114-2023

Subject Hows Corner Superfund Site Plymouth Maine Transmittal of Scope of Work - Technical Impracticability Evaluation and Field Work for Hydraulic Containment System Design

Dear Bill

Three copies of the Final Scope of Work (SOW) for Technical Impracticability Evaluation and Field Work for Hydraulic Containment System Design are enclosed Three paper copies of the report are also being provided to MEDEP today

Please contact me at 1-800-426-4262 if you have any questions about the enclosed SOW Bill we appreciate your continued efforts in working with us to bring this project to a successful completion

Sincerely

WOODARD amp CURRAN INC

n^f

Thomas R Eschner Senior Project Manager

Enclosures

cc Claudia B Sait MEDEP (3 copies) David P Littell Pierce Atwood (1 copy) Jim Rawson General Electric (1 copy) Kristin Larson Skadded Arps Slate Meather amp Flom (1 copy)

41 Hutchins Drive i Portland Maine 04102 i 207-774-2112 i 207-774-6635 (Fax) i 1-800-426-4262 i wwwwoodardcurrancom

TABLE OF CONTENTS

SECTION NO TITLE PAGE NO

10 INTRODUCTION 1

20 SITE DESCRIPTION AND INVESTIGATION HISTORY 3

30 INVESTIGATION TECHNICAL APPROACH 6 31 INVESTIGATIVE APPROACH 6

311 Task 1 - Project Planning 7 312 Task 2 - Field Investigation 7 313 Task 3 - TI Evaluation and Reporting 19

40 SCHEDULE 22

50 ACRONYMS 24

LIST OF FIGURES

FIGURE NO TITLE PAGE NO

Figure 1-1 Site Locus Plan 2 Figure 2-1 Site Plan Detail 4 Figure 3-1 Proposed Well Locations 10 Figure 4-1 Proposed Project Schedule 23

LIST OF TABLES

TABLE NO TITLE PAGE NO

Table 3-1 Rationale for Proposed Well Locations 11

TISOW WOODARD amp CURRAN TOC-I September 302003 20564309

10 INTRODUCTION

The purpose of this scope of work (SOW) is to provide an overview of the tasks proposed in response to

United States Environmental Protection Agency (USEPA) guidance and site-specific requirements for the

Technical Impracticability (TI) Evaluation of the West SiteHows Corner Superfund Site (Site) as well as

an overview of a pumping test to support design of the hydraulic containment system selected in the

Interim Record of Decision (ROD) for the Non Source-Area Groundwater at the Site (USEPA 2002)

Details of the site characterization activities described in this SOW will be provided in the three

subsequent major project-planning documents that will be produced after agreement is reached on scope

and content of the SOW

bull Work Plan

bull Health and Safety Plan (HASP)

bull Quality Assurance Project Plan (QAPP)-Including the Sampling and Analysis Plan

(SAP)

The Site is located in Plymouth Maine as depicted in Figure 1-1 The Potentially Responsible Party

Group (the PRP Group) for the Site has been asked to implement additional site characterization to

address data gaps identified by the USEPA (USEPA 2003) so that a final ROD can be issued for the Site

In addition the data developed from the pumping test described in this SOW will be used to evaluate the

number and spacing of wells for development of the hydraulic containment system design This SOW

specifies the approach proposed by the PRP Group to (1) improve the understanding of groundwater

movement including solute transport in the fractured bedrock aquifer (2) establish the limits of the TI

zone at the Site and (3) provide information that will assist in designing the hydraulic containment

system specified in the Interim ROD

This SOW is organized into four Sections Section 2 presents a brief Site description and history

followed by a discussion of the Site Conceptual Model that was previously developed for the Site based

on existing data Section 3 presents the proposed technical approach to the investigation including

rationale for well locations and investigation techniques as well as a pumping test that will be used to

assist in development of the hydraulic containment system design that will be conducted pursuant to the

authority of the Administrative Order by Consent (AOC) for the Remedial Design (RD) Details

regarding the development of the hydraulic containment system will be presented in the Remedial Design

Work Plan Section 4 presents the overall schedule for implementing this TI SOW including the

pumping test and completing the TI Evaluation Report

TISOW WOODARDampCURRAN 1 September 302003 20564309

I I1 J1 - ^

i i i KA ^$^ c E I I F L Ti M O U T H

C -j--MlI e ^P

I

I Source USGS Topographic 75-minute Series Quadrangles

Plymouth ME 1982 and Dixmont ME 1982 bull MAINR

c Figure 1-1 Quadrangle Location Site Location Map

Hows Corner Superfund Site c Plymouth Maine 4000

WOODARDampCURRAN 99503716risiteloc

I

bull 20 SITE DESCRIPTION AND INVESTIGATION HISTORY

The Site is located in east-central Maine in the town of Plymouth The Site includes a 17-acre parcel of

land owned by George West and is comprised of Operable Unit One (Non-source Area Groundwater) and

the Source Area Groundwater as generally depicted on Figure 2-1 Mr West used a small two-acre

portion of the site to operate a waste oil facility from 1965 to 1980 During investigations conducted by

the Maine Department of Environmental Protection (MEDEP) in the early 1990s a fence was placed

ft around this 2-acre portion of the Site This fenced area is referred to in the RIFS and the Interim ROD as

the Source Area (Figure 2-1) Source Area Groundwater however is defined in the ROD as

d groundwater with total volatile organic compound (VOC) concentration equal to or greater than 10 parts

per million (ppm) and may exist outside the 2-acre fenced area

m From October 1999 to May 2001 the PRP Group with oversight by USEPA and MEDEP conducted a

Remedial Investigation (RI) to determine the nature and extent of contamination to characterize the fate

and transport of contaminants and to assess the potential risks that the contamination poses to both

human health and the environment The findings of the RI show that VOCs in groundwater and

polychlorinated biphenyls (PCBs) in soil within the fenced area of the Site were present at concentrations

exceeding the target risk levels of 105 carcinogenic risk or a Hazard Index of 1 for non-carcinogenic risk

In addition modeling of Site groundwater shows that groundwater flows radially away from the source

area and discharges to the surface in many spring-fed ponds and to the surface on the flanks of the hill

bull Under current conditions contamination from the Site has reached its maximum extent This

groundwater plume consists of both Source Area Groundwater which is defined as groundwater where

total VOC concentrations are greater than or equal to 10 ppm and Non-Source Area Groundwater which

is groundwater containing total VOC concentrations below 10 ppm (USEPA 2002) (see Figure 2-1) A

(0 detailed description of the distribution and extent of groundwater contamination at the Site is provided in

sections 40 and 50 of the RI Report

4 In July 2002 the PRP Group with oversight by USEPA and MEDEP completed a Feasibility Study (FS)

to develop and evaluate a range of remedial alternatives to address potential risks to human health and the

environment that were identified during the RI for the non-source area groundwater

TISOW WOODARD amp CURRAN 3 September 302003 20564309

bull 20 SITE DESCRIPTION AND INVESTIGATION HISTORY

The Site is located in east-central Maine in the town of Plymouth The Site includes a 17-acre parcel of

land owned by George West and is comprised of Operable Unit One (Non-source Area Groundwater) and

the Source Area Groundwater as generally depicted on Figure 2-1 Mr West used a small two-acre

portion of the site to operate a waste oil facility from 1965 to 1980 During investigations conducted by

the Maine Department of Environmental Protection (MEDEP) in the early 1990s a fence was placed

ft around this 2-acre portion of the Site This fenced area is referred to in the RIFS and the Interim ROD as

the Source Area (Figure 2-1) Source Area Groundwater however is defined in the ROD as

d groundwater with total volatile organic compound (VOC) concentration equal to or greater than 10 parts

per million (ppm) and may exist outside the 2-acre fenced area

m From October 1999 to May 2001 the PRP Group with oversight by USEPA and MEDEP conducted a

Remedial Investigation (RI) to determine the nature and extent of contamination to characterize the fate

and transport of contaminants and to assess the potential risks that the contamination poses to both

human health and the environment The findings of the RI show that VOCs in groundwater and

polychlorinated biphenyls (PCBs) in soil within the fenced area of the Site were present at concentrations

exceeding the target risk levels of 105 carcinogenic risk or a Hazard Index of 1 for non-carcinogenic risk

In addition modeling of Site groundwater shows that groundwater flows radially away from the source

area and discharges to the surface in many spring-fed ponds and to the surface on the flanks of the hill

bull Under current conditions contamination from the Site has reached its maximum extent This

groundwater plume consists of both Source Area Groundwater which is defined as groundwater where

total VOC concentrations are greater than or equal to 10 ppm and Non-Source Area Groundwater which

is groundwater containing total VOC concentrations below 10 ppm (USEPA 2002) (see Figure 2-1) A

(0 detailed description of the distribution and extent of groundwater contamination at the Site is provided in

sections 40 and 50 of the RI Report

4 In July 2002 the PRP Group with oversight by USEPA and MEDEP completed a Feasibility Study (FS)

to develop and evaluate a range of remedial alternatives to address potential risks to human health and the

environment that were identified during the RI for the non-source area groundwater

TISOW WOODARD amp CURRAN 3 September 302003 20564309

NonmdashSource Area Groundwater

Source Atea Groundirater

17mdashAcre George West Property

_bdquoVOCugllppm

0

| n r nA

= Volatile Orgamc Compound _ = Microgram per Liter

= Parts per Million

300 600

FEET

Notes 1 Shaded areas based on Maximum Extent of total VOCs j n e | t h e r D e c e m b e r 1 9 9 9 P r e _ R 0 D o r J u n e 2 0 0 0 Supplemental Sampling Events

2 Source Area Groundwater is defined as groundwater with total VOC concentration equal to or greater than 10000 ugl (10 ppm) Extent of Source Area Groundwater plume inferred east of 2-Acre Fenced Area

3 Non Source Area Groundwater is defined as groundwater with total VOC concentrations less then 10000 ugl (10ppm)

Figure 2-1 Site Plan Detail

Hows Corner Superfund Site Plymouth Maine

WOODARD ampCURRAN Engineering bull Science Operations

205643wipsite sowu2-1A

0

Soil within the fenced area of the Site that presented a human health risk was excavated during pilot

testing for the FS and disposed of off-site The three remedial alternatives evaluated in the FS (WampC

bull 2002) were

bull No further Action

lt$ bull Limited Action and

bull Hydraulic Containment

$t As stated in Section 40 of the FS the possible presence of a remnant dense non-aqueous phase liquid

(DNAPL) source within the groundwater plume raises the question as to whether or not complete

restoration of the aquifer can be achieved in a reasonable period of time (eg less than 100 years)

Because of the uncertainties associated with the groundwater recharge rate the mass of DNAPL in

^ Source Area Groundwater the fractional organic carbon (foe) in the bedrock and the tetrachloroethene

(PCE) organic carbon partitioning coefficient (Koc) the restoration potential of both Source Area and

^ Non-Source Area Groundwater could not be assessed within a reasonable degree of scientific certainty in

the FS

The Interim ROD for Operable Unit One Non-Source Area Groundwater (USEPA 2002) was completed

in September 2002 The remedy selected in the Interim ROD consisted of

bull Installation of groundwater extraction and treatment system to contain Source Area Groundwater

bull Monitoring of surface water sediments and Non-Source Area Groundwater to measure the

progress of natural attenuation toward meeting Applicable or Relevant and Appropriate

Requirements (ARARs)

^9 bull Residential well monitoring with a public water contingency

bull Institutional Controls to prevent use of both Source and Non-Source Area Groundwater and

( i bull Five-year Reviews

4) Following completion of the FS Report and preparation of the Interim ROD for Operable Unit One

USEPA requested that further site characterization be completed to assist in making a determination

Jsect concerning the feasibility of attaining ARARs within a reasonable time Section 3 of this SOW outlines

the tasks proposed by the PRP Group to address the requirement for additional Site data necessary for a

pound TI evaluation and containment system design

TISOW WOODARD amp CURRAN 5 September 302003 20564309

0

Soil within the fenced area of the Site that presented a human health risk was excavated during pilot

testing for the FS and disposed of off-site The three remedial alternatives evaluated in the FS (WampC

bull 2002) were

bull No further Action

lt$ bull Limited Action and

bull Hydraulic Containment

$t As stated in Section 40 of the FS the possible presence of a remnant dense non-aqueous phase liquid

(DNAPL) source within the groundwater plume raises the question as to whether or not complete

restoration of the aquifer can be achieved in a reasonable period of time (eg less than 100 years)

Because of the uncertainties associated with the groundwater recharge rate the mass of DNAPL in

^ Source Area Groundwater the fractional organic carbon (foe) in the bedrock and the tetrachloroethene

(PCE) organic carbon partitioning coefficient (Koc) the restoration potential of both Source Area and

^ Non-Source Area Groundwater could not be assessed within a reasonable degree of scientific certainty in

the FS

The Interim ROD for Operable Unit One Non-Source Area Groundwater (USEPA 2002) was completed

in September 2002 The remedy selected in the Interim ROD consisted of

bull Installation of groundwater extraction and treatment system to contain Source Area Groundwater

bull Monitoring of surface water sediments and Non-Source Area Groundwater to measure the

progress of natural attenuation toward meeting Applicable or Relevant and Appropriate

Requirements (ARARs)

^9 bull Residential well monitoring with a public water contingency

bull Institutional Controls to prevent use of both Source and Non-Source Area Groundwater and

( i bull Five-year Reviews

4) Following completion of the FS Report and preparation of the Interim ROD for Operable Unit One

USEPA requested that further site characterization be completed to assist in making a determination

Jsect concerning the feasibility of attaining ARARs within a reasonable time Section 3 of this SOW outlines

the tasks proposed by the PRP Group to address the requirement for additional Site data necessary for a

pound TI evaluation and containment system design

TISOW WOODARD amp CURRAN 5 September 302003 20564309

bull 30 INVESTIGATION TECHNICAL APPROACH

On behalf of the PRP Group Woodard amp Curran (WampC) has developed a proposed SOW in response to

bull USEPAs request for additional field tasks to further refine the cleanup times presented in the 2002

Interim ROD for this site This approach has been designed to evaluate the following additional data

lt9 needs identified by USEPA to refine cleanup times

4t bull Aquifer hydraulic conductivity

bull Aquifer porosity (matrix and bulk) and

H bull Partitioning of contaminants to the bedrock

^ The data from these additional field tasks will also be used by USEPA to define the TI zone for the Final

ROD and assist the PRPs in developing the design for the hydraulic containment system for the Source

j Area Groundwater which is being conducted under the authority of the RD AOC Details regarding

development of the hydraulic containment system will be presented in the Remedial Design Work Plan

The proposed TI SOW is based on information available during its preparation and may be amended

subject to USEPA approval as additional information regarding subsurface conditions becomes available

during the field investigation The following section describes the overall field investigation approach A

comprehensive presentation of each task in the field investigation will be provided in the Sampling and

bull Analysis Plan (SAP) which will be amended following approval of a final scope of work

bull0 31 Investigative Approach

j The work proposed to meet the additional data requirements stated by USEPA consists of the three

primary tasks described below and further outlined as subtasks Brief descriptions of each task are

presented in the subsections that follow

Task 1 - Project Planning

Task 2 - Field Investigation

Task 3 - TI Evaluation and Reporting

WOODARD amp CURRAN 6 September 302003 20564309

311 Task 1 - Project Planning

Project planning is the first task and includes the following five subtasks

bull Finalize the SOW

bull Prepare work plan

bull Revise existing site-specific Quality Assurance Project Plan (QAPP) Sampling and Analysis

Plan (SAP) and Health and Safety Plan (HASP) and

bull Secure subcontractor contracts

bull Mobilize to the Site and establish a field office

In order to finalize the SOW for this TI evaluation it is anticipated that a minimum of one meeting will

occur between the PRP Group USEPA MEDEP and WampC Once the SOW is finalized the QAPP

SAP and HASP (the Plans) will be revised to incorporate necessary modifications to reflect the agreed-

upon work methods and technology The SAP will be modified to include a detailed plan for the

additional field activities Once the Plans have been revised and the Work Plan prepared they will be

submitted to USEPA for review USEPA comments will be incorporated into the plans and final

approved plans will be issued

After final plans have been issued WampC will negotiate contracts with subcontractors for certain field

activities including boring and monitoring well installation geophysical survey packer testing and

investigation-derived waste (IDW) storage and disposal It is anticipated that a second meeting between

the parties may be needed prior to the commencement of the field activities

Because of the duration of the field activities described in this SOW and the need for on-site evaluation of

field results in order to make program decisions during the investigation WampC will mobilize a trailer to

the Site to serve as a field office The trailer will be equipped with telephone and fax machine

312 Task 2 - Field Investigation

The field investigation task will include the following subtasks

bull Subtask 1 - Boring installation

bull Subtask 2 - Borehole geophysics

TISOW

WOODARDampCURRAN 7 September 302003 20564309

0

0 bull Subtask 3 - Packer testing

bull Subtask 4 - Sampling and analysis

bull bull Subtask 5 - Monitoring well installation

bull Subtask 5 - Pumping test and

bull Subtask 6 - Tracer test

Each of the subtasks is summarized below however a comprehensive discussion of these subtasks and

associated methodologies will be provided in the SAP

Subtask 1 - Boring Installation

j Information obtained during the installation of the new borings will be used in the evaluation of the

aquifer hydraulic conductivity and the analysis of other aquifer properties (eg porosity fracture

frequency) For this subtask it is anticipated that one angled boring will be completed to a depth of 150

feet (ft) below ground surface (bgs) One additional angled boring and four new vertical bedrock borings

will be completed to depths of approximately 100 ft bgs This depth is consistent with the depth

evaluated in the RI and will allow evaluation of bedrock and groundwater properties to depths below the

transition from less competent to more competent bedrock (approximately 50 to 80 ft bgs)

m One additional vertical boring will be installed to a depth of 100 ft bgs as the pumping well location for

bull the pumping test The pumping well location will be based on the results of field work conducted prior to

its installation The proposed drilling program is designed to enhance understanding of the flow system

by aligning new boring locations with existing wells to characterize hydraulic properties of the fracture

network and bulk bedrock Furthermore the program allows for additional characterization of

M contamination in the Source Area groundwater The rationale for the boring locations is summarized in

Table 3-1 and the proposed locations of the borings are depicted on Figure 3-1 Actual locations may

M vary depending on field conditions and accessibility

jlt The drilling protocol employed during installation of both the angled and the vertical wells will allow for

evaluation of the potential presence of DNAPL in the rock and the need for modifications to the drilling

method if DNAPL is detected If sheen or product is observed in the return water core or cuttings from a

boring an interface probe may be employed to determine whether a NAPL is present in the boring

Based on the presence of DNAPL the boring may be terminated at a shallower depth than planned the

J TISOW 4 1 WOODARD amp CURRAN 8 September 302003

20564309

location may be abandoned or other practices may be employed to reduce the potential for causing

downward migration of DNAPL The protocol will be described in the Work Plan and the SAP

Angled Borings Two angled borings will be installed using air-hammer drilling methods The first

angled boring (AW-201) will be installed to a depth of 150 ft bgs in the vicinity of existing well MWshy

106 northeast of and outside of the source area and within the dissolved phase groundwater plume This

well will be angled from the surface toward the southeast at depth in order to intersect as many northwest-

dipping near-vertical fractures as possible The angle of this boring will be approximately 30deg to 40deg

from the vertical resulting in a surface projection of approximately 84 to 126 ft and total length of

approximately 173 to 195 ft The second angled boring (AW-202) will be installed to a depth of 100 ft

bgs in the vicinity of the existing MW-2 well cluster within the source area This well also will be angled

from the surface toward the southeast at depth in order to intersect near-vertical fractures The angle of

this boring will be approximately 30deg to 40deg from the vertical resulting in a surface projection of

approximately 58 to 84 ft and total length of approximately 115 to 130 ft

m

4

sect

i

TISOW WOODARD amp CURRAN 9 September 302003 20564309

Table 3-1

Rationale for Proposed Well Locations

Hows Corner Technical Impracticability Evaluation and Field work for Hydraulic Containment System Design

Well Identification

AW-201

AW-202

MW-203

MW-204

MW-205

MW-206

PW-207

Boring Orientation

Angled

Angled

Vertical

Vertical

Vertical

Vertical

Vertical

Minimum Boring Diameter (inches)

4

4

4

4

4

4

6

Drilling Method

Air Hammer

Air Hammer

Coring

Air Hammer

Air Hammer

Air Hammer

Core Air Hammer Over -drilling

Source Area Non-Source Area

Non-Source Area

Source Area

Non-Source Area

Non-Source Area

Source Area

Source Area

Source Area

Rationale for Boring

bull Intercept near-vertical fractures to understand subsurface geology bull Aid in iting MW-203 bull Intercept near-vertical fractures to understand subsurface geology bull Aid in siting PW-201 (Pumping well) bull ion of contamination bull 1 future monitoring location bull Potential reinjection well for hydraulic containment system bull Core for matrix diffusion evaluation bullbullbullbull Ibullbullbullbull 1bullbullbullbull 1bullbull bull 1

tion point for pumping test tion point in tracer test ion of contamination

future monitoring location tion point for pumping test tion point in tracer test ion of contamination

future monitoring location tion point for pumping test tion point in tracer test ion of contamination

future monitoring location tion point for pumping test

test well extraction well

bull Core for matrix diffusion evaluation bull i point for tracer test

TISOW September 30 2003 WOODARD amp CURRAN 20564309

MW-105D MW-5B

Primary Bedding Secondary Cleavage

Tertsry Fracturing

NOTE A total of 60 observations warn made rtrtjs roprtraont tticopy number of obsafvatk noted wtthln each azimutha) segment

MW-1 1 3D euro MW-205

2 AcreSource

Fenced-^ Area i

MW-103D MW-103S

17-Acre Property Boundary

MW-104D MW-1041 bull

MW-104S

Legend Figure 3-1 J Proposed Monitoring Well Proposed Well Locations

o- Site Property Boundary bull^bullProposed Pumping Well Hows Corner Superfund Site -xmdashx- Source Area Plymouth Maine

^ ^Proposed Angled Well bullamp Existing Monitoring Well bullWDODARDampCURRAN

Englnoortng bull Science bull Operations 205643wipsite-8OlaquoAx-opt-1-2-u3-1D

bull During the installation of each angled boring observations will be made regarding water gainloss

drilling rate and bit behavior to assess the depth of potential fractures In addition water levels will be

9 measured in nearby borings using either hand measurements data loggers or both to evaluate

connectivity between locations A change in water level in a nearby boring will indicate a hydraulic

at connection between the borings Borehole geophysics will also be performed on the borings (See Subtask

2 below) Information from each angled boring will be used to site an adjacent vertical well (MW-203

^ and PW-207) so that it intercepts a fracture observed in the angled boring

^ Vertical Borings Two of the vertical borings will be completed with rotary diamond coring to

approximately 100 ft bgs These borings will be adjacent to the angled borings described above One of

^ the cored borings (MW-203) will be located near MW-106 outside of the source area within the

dissolved-phase groundwater plume (see Figure 3-1) The other cored boring (PW-207) will be the

pumping well which is anticipated to be located within the source area in the vicinity of the existing

MW-2 well cluster Coring will allow data collection for several purposes including direct observation

of bedrock for determination of the nature of the rock matrix determination of the location and nature of

fractures and the degree of fracturing comparison with geophysical logs (Subtask 2) to verify

interpretation of the logs and collection of core samples for analysis (Subtask 4)

The remaining borings will be located east of the 2-acre fenced area within or near the periphery of the

source area and will be sited to align approximately with existing wells based on the known fracture

orientations at the Site (MW-204 and MW-205) or with new wells based on the known fracture

pound orientations at the Site (MW-206) Data from these locations in conjunction with the other borings

installed as part of this TI SOW and the existing wells will be used in the interpretation of the pumping

^ test (Subtask 6) and tracer test (Subtask 7) In addition these three borings will further delineate

contamination and provide potential monitoring locations for long-term monitoring Each of these

^ borings will be advanced to approximately 100 ft bgs with a minimum four-inch diameter air hammer

^ During the installation of each boring observations will be made regarding water gainloss drilling rate

and bit behavior to assess the depth of potential fractures In addition water levels will be measured in

nearby borings using either hand measurements data loggers or both to evaluate connectivity between

locations A change in water level in a nearby boring will indicate a hydraulic connection between the

TISOW WOODARD amp CURRAN 12 September 302003 20564309

borings Borehole geophysics and packer testing will also be performed on the borings (See Subtasks 2

and 3 below)

Drilling water will be containerized on site and treated through granular activated carbon (GAC) Treated

water will be analyzed to verify that PCB and VOC concentrations have been reduced to below ARARs

prior to discharge to the ground surface Cuttings will be spread on the ground surface at the site

consistent with the Remedial Investigation work plan

It is anticipated that up to 10 core samples from each cored boring (total of 20 cores) will be collected and

submitted to an off-site laboratory for analyses of porosity (matrix and bulk) permeability bulk density

and fraction of organic carbon (f^) using methods described in Subtask 4

Subtask 2 - Borehole Geophysics

To supplement information on fracture location and connectivity obtained during boring advancement a

borehole geophysical survey will be conducted on the newly installed bedrock borings to evaluate the

nature and orientation of water bearing fractures in the borings The survey will be performed at the

completion of the angled borings and again at the completion of the vertical borings The information

obtained during the survey may be used to identify the location of subsequent boring(s) by refining the

understanding of the depth aperture and orientation of bedrock fractures The following measurements

are proposed for the new borings caliper fluid temperature fluid resistivity and acoustic televiewer

(ATV) Single-point resistively and 16 inch normal measurements will also be made in the first two

borings installed and the data will be compared to data from the other geophysical logs to determine if

the measurements confirm and significantly improve the interpretation regarding the presence of water-

bearing fractures If the measurements are applicable to identification of fractures they may be included

in lieu of other geophysical logs in the remainder of the borings

Subtask 3 - Packer Testing

To further refine information on the aquifer hydraulic conductivity the hydraulic connection between

fractures in the borings will be evaluated during packer testing of vertical borings The data will be used

to estimate the hydraulic conductivity of specific fractures and fracture zones The packer testing will be

performed after the vertical borings have been installed and the borehole geophysical survey completed

TISOW WOODARD amp CURRAN 13 September 30 2003 20564309

MW-105D MW-5B

Primary Bedding Secondary Cleavage

Tertsry Fracturing

NOTE A total of 60 observations warn made rtrtjs roprtraont tticopy number of obsafvatk noted wtthln each azimutha) segment

MW-1 1 3D euro MW-205

2 AcreSource

Fenced-^ Area i

MW-103D MW-103S

17-Acre Property Boundary

MW-104D MW-1041 bull

MW-104S

Legend Figure 3-1 J Proposed Monitoring Well Proposed Well Locations

o- Site Property Boundary bull^bullProposed Pumping Well Hows Corner Superfund Site -xmdashx- Source Area Plymouth Maine

^ ^Proposed Angled Well bullamp Existing Monitoring Well bullWDODARDampCURRAN

Englnoortng bull Science bull Operations 205643wipsite-8OlaquoAx-opt-1-2-u3-1D

bull During the installation of each angled boring observations will be made regarding water gainloss

drilling rate and bit behavior to assess the depth of potential fractures In addition water levels will be

9 measured in nearby borings using either hand measurements data loggers or both to evaluate

connectivity between locations A change in water level in a nearby boring will indicate a hydraulic

at connection between the borings Borehole geophysics will also be performed on the borings (See Subtask

2 below) Information from each angled boring will be used to site an adjacent vertical well (MW-203

^ and PW-207) so that it intercepts a fracture observed in the angled boring

^ Vertical Borings Two of the vertical borings will be completed with rotary diamond coring to

approximately 100 ft bgs These borings will be adjacent to the angled borings described above One of

^ the cored borings (MW-203) will be located near MW-106 outside of the source area within the

dissolved-phase groundwater plume (see Figure 3-1) The other cored boring (PW-207) will be the

pumping well which is anticipated to be located within the source area in the vicinity of the existing

MW-2 well cluster Coring will allow data collection for several purposes including direct observation

of bedrock for determination of the nature of the rock matrix determination of the location and nature of

fractures and the degree of fracturing comparison with geophysical logs (Subtask 2) to verify

interpretation of the logs and collection of core samples for analysis (Subtask 4)

The remaining borings will be located east of the 2-acre fenced area within or near the periphery of the

source area and will be sited to align approximately with existing wells based on the known fracture

orientations at the Site (MW-204 and MW-205) or with new wells based on the known fracture

pound orientations at the Site (MW-206) Data from these locations in conjunction with the other borings

installed as part of this TI SOW and the existing wells will be used in the interpretation of the pumping

^ test (Subtask 6) and tracer test (Subtask 7) In addition these three borings will further delineate

contamination and provide potential monitoring locations for long-term monitoring Each of these

^ borings will be advanced to approximately 100 ft bgs with a minimum four-inch diameter air hammer

^ During the installation of each boring observations will be made regarding water gainloss drilling rate

and bit behavior to assess the depth of potential fractures In addition water levels will be measured in

nearby borings using either hand measurements data loggers or both to evaluate connectivity between

locations A change in water level in a nearby boring will indicate a hydraulic connection between the

TISOW WOODARD amp CURRAN 12 September 302003 20564309

borings Borehole geophysics and packer testing will also be performed on the borings (See Subtasks 2

and 3 below)

Drilling water will be containerized on site and treated through granular activated carbon (GAC) Treated

water will be analyzed to verify that PCB and VOC concentrations have been reduced to below ARARs

prior to discharge to the ground surface Cuttings will be spread on the ground surface at the site

consistent with the Remedial Investigation work plan

It is anticipated that up to 10 core samples from each cored boring (total of 20 cores) will be collected and

submitted to an off-site laboratory for analyses of porosity (matrix and bulk) permeability bulk density

and fraction of organic carbon (f^) using methods described in Subtask 4

Subtask 2 - Borehole Geophysics

To supplement information on fracture location and connectivity obtained during boring advancement a

borehole geophysical survey will be conducted on the newly installed bedrock borings to evaluate the

nature and orientation of water bearing fractures in the borings The survey will be performed at the

completion of the angled borings and again at the completion of the vertical borings The information

obtained during the survey may be used to identify the location of subsequent boring(s) by refining the

understanding of the depth aperture and orientation of bedrock fractures The following measurements

are proposed for the new borings caliper fluid temperature fluid resistivity and acoustic televiewer

(ATV) Single-point resistively and 16 inch normal measurements will also be made in the first two

borings installed and the data will be compared to data from the other geophysical logs to determine if

the measurements confirm and significantly improve the interpretation regarding the presence of water-

bearing fractures If the measurements are applicable to identification of fractures they may be included

in lieu of other geophysical logs in the remainder of the borings

Subtask 3 - Packer Testing

To further refine information on the aquifer hydraulic conductivity the hydraulic connection between

fractures in the borings will be evaluated during packer testing of vertical borings The data will be used

to estimate the hydraulic conductivity of specific fractures and fracture zones The packer testing will be

performed after the vertical borings have been installed and the borehole geophysical survey completed

TISOW WOODARD amp CURRAN 13 September 30 2003 20564309

bull During the installation of each angled boring observations will be made regarding water gainloss

drilling rate and bit behavior to assess the depth of potential fractures In addition water levels will be

9 measured in nearby borings using either hand measurements data loggers or both to evaluate

connectivity between locations A change in water level in a nearby boring will indicate a hydraulic

at connection between the borings Borehole geophysics will also be performed on the borings (See Subtask

2 below) Information from each angled boring will be used to site an adjacent vertical well (MW-203

^ and PW-207) so that it intercepts a fracture observed in the angled boring

^ Vertical Borings Two of the vertical borings will be completed with rotary diamond coring to

approximately 100 ft bgs These borings will be adjacent to the angled borings described above One of

^ the cored borings (MW-203) will be located near MW-106 outside of the source area within the

dissolved-phase groundwater plume (see Figure 3-1) The other cored boring (PW-207) will be the

pumping well which is anticipated to be located within the source area in the vicinity of the existing

MW-2 well cluster Coring will allow data collection for several purposes including direct observation

of bedrock for determination of the nature of the rock matrix determination of the location and nature of

fractures and the degree of fracturing comparison with geophysical logs (Subtask 2) to verify

interpretation of the logs and collection of core samples for analysis (Subtask 4)

The remaining borings will be located east of the 2-acre fenced area within or near the periphery of the

source area and will be sited to align approximately with existing wells based on the known fracture

orientations at the Site (MW-204 and MW-205) or with new wells based on the known fracture

pound orientations at the Site (MW-206) Data from these locations in conjunction with the other borings

installed as part of this TI SOW and the existing wells will be used in the interpretation of the pumping

^ test (Subtask 6) and tracer test (Subtask 7) In addition these three borings will further delineate

contamination and provide potential monitoring locations for long-term monitoring Each of these

^ borings will be advanced to approximately 100 ft bgs with a minimum four-inch diameter air hammer

^ During the installation of each boring observations will be made regarding water gainloss drilling rate

and bit behavior to assess the depth of potential fractures In addition water levels will be measured in

nearby borings using either hand measurements data loggers or both to evaluate connectivity between

locations A change in water level in a nearby boring will indicate a hydraulic connection between the

TISOW WOODARD amp CURRAN 12 September 302003 20564309

borings Borehole geophysics and packer testing will also be performed on the borings (See Subtasks 2

and 3 below)

Drilling water will be containerized on site and treated through granular activated carbon (GAC) Treated

water will be analyzed to verify that PCB and VOC concentrations have been reduced to below ARARs

prior to discharge to the ground surface Cuttings will be spread on the ground surface at the site

consistent with the Remedial Investigation work plan

It is anticipated that up to 10 core samples from each cored boring (total of 20 cores) will be collected and

submitted to an off-site laboratory for analyses of porosity (matrix and bulk) permeability bulk density

and fraction of organic carbon (f^) using methods described in Subtask 4

Subtask 2 - Borehole Geophysics

To supplement information on fracture location and connectivity obtained during boring advancement a

borehole geophysical survey will be conducted on the newly installed bedrock borings to evaluate the

nature and orientation of water bearing fractures in the borings The survey will be performed at the

completion of the angled borings and again at the completion of the vertical borings The information

obtained during the survey may be used to identify the location of subsequent boring(s) by refining the

understanding of the depth aperture and orientation of bedrock fractures The following measurements

are proposed for the new borings caliper fluid temperature fluid resistivity and acoustic televiewer

(ATV) Single-point resistively and 16 inch normal measurements will also be made in the first two

borings installed and the data will be compared to data from the other geophysical logs to determine if

the measurements confirm and significantly improve the interpretation regarding the presence of water-

bearing fractures If the measurements are applicable to identification of fractures they may be included

in lieu of other geophysical logs in the remainder of the borings

Subtask 3 - Packer Testing

To further refine information on the aquifer hydraulic conductivity the hydraulic connection between

fractures in the borings will be evaluated during packer testing of vertical borings The data will be used

to estimate the hydraulic conductivity of specific fractures and fracture zones The packer testing will be

performed after the vertical borings have been installed and the borehole geophysical survey completed

TISOW WOODARD amp CURRAN 13 September 30 2003 20564309

borings Borehole geophysics and packer testing will also be performed on the borings (See Subtasks 2

and 3 below)

Drilling water will be containerized on site and treated through granular activated carbon (GAC) Treated

water will be analyzed to verify that PCB and VOC concentrations have been reduced to below ARARs

prior to discharge to the ground surface Cuttings will be spread on the ground surface at the site

consistent with the Remedial Investigation work plan

It is anticipated that up to 10 core samples from each cored boring (total of 20 cores) will be collected and

submitted to an off-site laboratory for analyses of porosity (matrix and bulk) permeability bulk density

and fraction of organic carbon (f^) using methods described in Subtask 4

Subtask 2 - Borehole Geophysics

To supplement information on fracture location and connectivity obtained during boring advancement a

borehole geophysical survey will be conducted on the newly installed bedrock borings to evaluate the

nature and orientation of water bearing fractures in the borings The survey will be performed at the

completion of the angled borings and again at the completion of the vertical borings The information

obtained during the survey may be used to identify the location of subsequent boring(s) by refining the

understanding of the depth aperture and orientation of bedrock fractures The following measurements

are proposed for the new borings caliper fluid temperature fluid resistivity and acoustic televiewer

(ATV) Single-point resistively and 16 inch normal measurements will also be made in the first two

borings installed and the data will be compared to data from the other geophysical logs to determine if

the measurements confirm and significantly improve the interpretation regarding the presence of water-

bearing fractures If the measurements are applicable to identification of fractures they may be included

in lieu of other geophysical logs in the remainder of the borings

Subtask 3 - Packer Testing

To further refine information on the aquifer hydraulic conductivity the hydraulic connection between

fractures in the borings will be evaluated during packer testing of vertical borings The data will be used

to estimate the hydraulic conductivity of specific fractures and fracture zones The packer testing will be

performed after the vertical borings have been installed and the borehole geophysical survey completed

TISOW WOODARD amp CURRAN 13 September 30 2003 20564309

bull

m

M

Drilling observations and information from borehole geophysics will be used to identify specific fractures

below the water table that are capable of transmitting water Prior to water injection for hydraulic

conductivity and fracture connectivity testing groundwater samples will be collected at selected intervals

for analysis of VOCs (See Subtask 4) Sampling intervals will be selected based on drilling observations

and logging results that indicate water is moving into or out of the borehole or that fractures exist to

promote water movement such as rapid increase in the amount of water returned rapid change in

temperature or highly fractured interval

^

^

bull

f$

Double packer testing will be performed at selected intervals within each newly installed boring It is

anticipated that up to six intervals per well will be tested for a maximum of 24 intervals and that for each

interval the test will include an approximate 15-minute injection of potable water at four progressively

increasing pressures Packer spacing is anticipated to be 10 ft however spacing may vary so that packers

are not located in potential fracture zones identified using information from rock cores drilling

observations and borehole geophysics The tests at an individual interval will be terminated if it appears

that the interval is not accepting water Care will be taken to minimize over-pumping or over-

pressurizing of the fractures The flow rate will be measured to evaluate the characteristics of the

fracture Water levels in adjacent borings will be measured during the packer testing to determine if a

hydraulic connection exists between the borings Water generated during packer testing will be

containerized on site and treated through GAC Treated water will be analyzed to verify that PCB and

VOC concentrations have been reduced to below ARARs prior to discharge to the ground surface

4 Subtask 4 Sampling and Analysis

~d

^

Rock and groundwater samples will be collected during the field program for laboratory analysis The

results of the analyses will be used to help refine the distribution of the plume and to estimate bedrock

properties These analyses will be used in conjunction with existing data during the TI evaluation to

refine cleanup times and establish the limits of the TI zone

As described in Subtask 1 it is anticipated that up to 10 core samples from each cored boring (total of 20

core samples) will be collected and submitted to an off-site laboratory for analyses of porosity (matrix and

bulk) permeability bulk density and fraction of organic carbon (f^) using existing industry methods

Subject to further evaluation of industry methods Woodard amp Curran proposes that porosity

TISOW WOODARD amp CURRAN20564309

14 September 302003

permeability and density will be measured using methods in the American Petroleum Institutes API RPshy

40 Fraction of organic carbon (f^) will be measured using either the LECO TOC method or Walkey-

Black method The LECO TOC method is a standard method in the petroleum industry and involves the

direct combustion of a ground rock sample The Walkey-Black method is a commonly used USEPA-

approved chemical oxidation method for determination of foe in soils In addition either method could be

used if a sample were scraped from a fracture surface To develop a reasonable range of f for Site

bedrock up to five samples will be selected from each boring from the unfractured matrix and up to five

from the fracture surfaces In addition Woodard amp Curran will evaluate the appropriateness of selecting

rock samples from a subset of the core samples from areas near fractures as well as from non-fractured

areas and submitting the samples for VOC analysis following methanol extraction

Results from these analyses will be used in conjunction with groundwater contaminant concentrations to

evaluate the significance of diffusion of contamination from the bedrock matrix in both the Source Area

and the Non-Source Area Although matrix diffusion likely is a significant factor in the determination of

cleanup times within the Source Area the potential applicability of matrix diffusion in the Non-Source

Area is not known These core analyses may provide evidence to assist in developing an estimate

through calculations of the effect of matrix diffusion on cleanup times

As noted in Subtask 3 prior to injection of water during packer testing groundwater samples will be

collected at selected intervals for analysis of volatile organic compounds (VOCs) Up to a total of 20

groundwater samples plus appropriate quality control samples will be collected from the newly installed

borings The samples will be submitted to an off-site laboratory for analysis Analytical results will be

validated in accordance with USEPA protocol and the data will be managed in WampCs existing

groundwater sampling analytical database for this site

Up to 21 existing monitoring wells from within or nearby the 17-acre property plus four new wells once

constructed will be sampled using low-flow techniques and submitted to an off-site laboratory for VOC

analysis Analytical results will be validated in accordance with USEPA protocol and the data will be

managed in WampCs existing groundwater sampling analytical database for this site

TISOW WOODARD amp CURRAN 15 September 302003 20564309

permeability and density will be measured using methods in the American Petroleum Institutes API RPshy

40 Fraction of organic carbon (f^) will be measured using either the LECO TOC method or Walkey-

Black method The LECO TOC method is a standard method in the petroleum industry and involves the

direct combustion of a ground rock sample The Walkey-Black method is a commonly used USEPA-

approved chemical oxidation method for determination of foe in soils In addition either method could be

used if a sample were scraped from a fracture surface To develop a reasonable range of f for Site

bedrock up to five samples will be selected from each boring from the unfractured matrix and up to five

from the fracture surfaces In addition Woodard amp Curran will evaluate the appropriateness of selecting

rock samples from a subset of the core samples from areas near fractures as well as from non-fractured

areas and submitting the samples for VOC analysis following methanol extraction

Results from these analyses will be used in conjunction with groundwater contaminant concentrations to

evaluate the significance of diffusion of contamination from the bedrock matrix in both the Source Area

and the Non-Source Area Although matrix diffusion likely is a significant factor in the determination of

cleanup times within the Source Area the potential applicability of matrix diffusion in the Non-Source

Area is not known These core analyses may provide evidence to assist in developing an estimate

through calculations of the effect of matrix diffusion on cleanup times

As noted in Subtask 3 prior to injection of water during packer testing groundwater samples will be

collected at selected intervals for analysis of volatile organic compounds (VOCs) Up to a total of 20

groundwater samples plus appropriate quality control samples will be collected from the newly installed

borings The samples will be submitted to an off-site laboratory for analysis Analytical results will be

validated in accordance with USEPA protocol and the data will be managed in WampCs existing

groundwater sampling analytical database for this site

Up to 21 existing monitoring wells from within or nearby the 17-acre property plus four new wells once

constructed will be sampled using low-flow techniques and submitted to an off-site laboratory for VOC

analysis Analytical results will be validated in accordance with USEPA protocol and the data will be

managed in WampCs existing groundwater sampling analytical database for this site

TISOW WOODARD amp CURRAN 15 September 302003 20564309

Subtask 5 - Monitoring Well Installation

Although it is anticipated that the newly installed borings will be left as open holes for tracer testing and

for pumping tests monitoring wells will be installed and developed in the newly installed borings unless

the USEPA MEDEP and PRP Group determine that the location is inappropriate for such use The

monitoring wells will be constructed of two-inch schedule 40 PVC screen and riser Screen intervals will

be selected based on the location of fractures identified during drilling geophysical logging and packer

testing A sand pack will be placed around the screen and will extend from approximately two ft below

the screen to approximately two ft above the screen

Subtask 6 - Pumping Test

WampC will conduct a single constant discharge pumping test to evaluate hydraulic properties of the

aquifer It is anticipated that the test will be conducted in a new pumping well in the vicinity of the

existing MW-2 well cluster within the source area Data from the pumping test will be used in

conjunction with other data from the investigation to improve the understanding of groundwater

movement and contaminant transport in the Source and Non-Source areas The results of the pumping

test will be used to refine the Site conceptual model as well as in the design of the hydraulic containment

system that is being constructed under the authority of the AOC for the RD

The groundwater pumping test will include the following components (1) Pumping test setup (2) Pretest

monitoring (3) Constant Discharge Pumping Test (4) Post-test monitoring and (5) Data Analysis

Pumping Test Setup In support of the groundwater pumping test WampC will install a pumping well

(PW-207) and procure and install the required groundwater extraction treatment and storage equipment at

the Site The well will be cored and over drilled to allow construction of a 4-inch well The location will

be in the vicinity of the MW-2 well cluster and be based upon results of the angled bedrock boring AWshy

202 The equipment will include but not be limited to

bull Down well pump plumbing and appurtances

bull Two (2) 20000 frac tanks

bull Groundwater transfer pumps and controls

bull Settlingaerationsand filtration treatment processes for the treatment of inorganics (if needed) and

nsow WOODARD amp CURRAN 16 September 302003 20564309

bull Granular activated carbon units for the treatment of dissolved organics in the groundwater

The groundwater treatment process will include the following processes 1) an oxidation and filtration

step to remove the inorganics from the groundwater and GAC units to treat the organic contaminants in

the extracted groundwater

Pretest Monitoring Prior to initiation of pumping WampC will monitor water levels in existing wells and

newly installed borings adjacent to the pumping well using a combination of hand measurements and data

loggers to develop an understanding of the piezometric surface under unstressed conditions The wells

proposed for water-level monitoring will be described in the work plan In addition all gauges

transducers flow meters and other equipment used in conducting the pumping tests shall be calibrated

before use

Constant Discharge Pumping Test The pumping test will be conducted in the source area using

newly-installed pumping well PW-207 It is anticipated that the test will be conducted at a pumping rate

of approximately 2 gallons per minute (gpm) for a period of 2 to 3 days however a higher or lower rate

may be shown to be appropriate based on the drilling and packer testing conducted during boring

installation Woodard amp Curran proposes to conduct this test using a vacuum-enhanced recovery system

(VERS) as described in the ROD so that the water level is not lowered appreciably in the vicinity of the

pumping well to prevent the potential migration of NAPLs to deeper bedrock zones The appropriateness

and feasibility of the VERS for the pumping test will be determined by field testing or literature

evaluation prior to completion of the Work Plan Because of the short duration of this test it is not

anticipated that stability of water levels will be reached in observation wells The test will however

provide information to estimate hydraulic conductivity and bedrock storage During the test the water

levels in the pumping well and selected monitoring wells will be logged continuously via down well data

loggers It is anticipated that water levels in approximately 24 wells will be measured using hand

measurements and data loggers

Groundwater extracted during the pumping test will be stored temporarily in an on-site frac tank prior to

on-site treatment and disposal

TISOW WOODARD amp CURRAN 17 September 302003 20564309

Post-Test Monitoring After the pump is turned off in the pumping well water levels will continue to be

monitored using hand measurements and data loggers until they have returned to within 10 of the preshy

test levels For planning purposes this has been estimated to be two weeks

Data Analysis Data collected during the pumping test will be analyzed with Aquifer Win32 Results of

the pumping test will be summarized in the summary data package for the TI Evaluation and the results

will also be used in the design of the hydraulic containment system specified in the Interim ROD that is

being conducted under the authority of the AOC for the RD Detail regarding use of the pumping test

data in hydraulic system design will be provided in the Remedial Design Work Plan

Subtask 7 - Tracer Test

WampC will conduct a tracer test using a conservative tracer to evaluate fracture connectivity porosity

dispersivity and matrix diffusion of the bedrock aquifer in both the Source Area and Non-Source Area

To increase the potential for success of this test results of the pumping test evaluation will be used to

revise the tracer test plan proposed here as necessary Following rebound of water levels after

completion of the pumping test WampC will initiate a single natural gradient tracer test The test will

consist of injecting a tracer into well PW-207 in the source area (Figure 3-1) for up to five days and

monitoring the tracers arrival in nearby wells Borehole geophysics core evaluation and packer testing

will be used to select the specific injection depth(s) in the well

A Tracer Test Work Plan will be completed prior to initiation of injection to determine the type quantity

and concentration of tracer based on the distance between the injection well and the monitoring wells A

conservative tracer that is one that is not preferentially adsorbed to rock or organic matter will be

selected for the tracer test Tracer injection equipment including tanks and flow-regulating and metering

equipment and pumps will be used to mix the tracer at the surface prior to injection Fractures may be

packered in the injection well and tracer solution will be injected at a rate determined during preparation

of the Tracer Test Work Plan During injection the potentiometric surface of the aquifer will be

monitored to verify that the potentiometric surface remains relatively constant during the injection

process

nsow WOODARD amp CURRAN 18 September 302003 20564309

Prior to injection of the tracer background concentration will be established by collecting samples from

up to six wells in the area of the tracer test and analyzing them for the tracer using an appropriate

analytical method Following injection of the tracer solutions the concentration of the tracer in

downgradient wells and borings will be measured A monitoring network will be established using nearby

monitoring wells Downhole probes will be installed in six new and existing wells near the injection well

to be identified in the work plan first to determine the background tracer concentrations and then to

monitor for the presence of the tracer upon initiation of the test Measurements will be collected at

periodic intervals to be determined based on the results of packer testing If an increase in tracer

concentration is detected or at a minimum on a weekly basis a water sample will be collected using low

flow sampling methodologies and analyzed in an off-site laboratory to evaluate the concentration of the

tracer The concentration of the tracer will be recorded Monitoring of the tracer concentration will

continue throughout the duration of the test The tracer will be allowed to flow with groundwater for one

month or until detected in wells in the vicinity of MW-106 whichever is shorter

313 Task 3 - TI Evaluation and Reporting

The TI Evaluation and reporting task includes the following five subtasks

bull Data evaluation

bull Summary data package

bull Draft TI Evaluation

bull Meetings with PRP Group and USEPA and

bull Revise and finalize TI Evaluation

As the subtasks of the field investigation are completed the data will be evaluated for the purpose of

addressing the data gaps identified by USEPA Specifically the data will be used to further refine the

cleanup times for non-source area groundwater presented in the Interim ROD

The data obtained during the field investigation will be reduced and evaluated and a summary data

package will be prepared that will include a discussion of the field activities completed and presentation

of the data It is anticipated that up to two meetings with USEPA will be necessary before the data

evaluation and summary report are completed

TISOW WOODARDampCURRAN 19 September 302003 20564309

Data collected during the pumping test will be analyzed with Aquifer Win32 Results will be summarized

in the summary data package and will also be presented as part of the RD submittals

Following submittal of the summary data package the TI evaluation will be prepared In accordance with

EPA guidance (1993) the TI waiver evaluation document will address the following topics

1 Specific ARARS or media cleanup standards for which TI determination is sought This section of the

TI Evaluation will identify the specific contaminants for which the TI determination is sought Based on

information available to date a waiver may be appropriate for pesticides PCBs chlorinated organic

compounds and other site-related contaminants that upon evaluation will not attain ARARs in a

reasonable period of time

2 Spatial area over which the TI waiver will apply The purpose of the additional site investigation

outlined in this SOW is to obtain the data necessary to further refine cleanup times presented in the

Interim ROD to determine what portions of the Site will not be expected to reach ARARs within a

reasonable time Consistent with TI guidance (USEPA 1993) the TI evaluation will specify the

horizontal and vertical extent of the area for which TI determination is sought Groundwater

concentration data from the RI and the TI SOW will be used to refine the distribution of the plume Data

from the drilling geophysical logging packer testing and pumping and tracer tests will be used to refine

the Site conceptual model and the cleanup times that will serve as the basis for establishing the scope and

nature of the TI zone

3 Conceptual Model The conceptual model forms the technical core of the TI Waiver Evaluation since

it provides basis for understanding of the restoration potential of the site The conceptual model outlines

the physical and hydrogeological constraints that hinder remediation or removal of Site contaminants and

it is the extent of these constraints rather than restoration timeframe alone that USEPA will use to

evaluate the necessity of the TI waiver of ARARs The conceptual model is the link between restoration

potential and restoration timeframe since it explains why proposed technologies are unlikely to work

either at all or within the desired 100-year timeframe

The Site conceptual model is not a mathematical model however as the result of the extensive modeling

and investigations of the site WampC has a strong understanding of the complex bedrock and overburden

TISOW WOODARDampCURRAN 20 September 302003 20564309

groundwater system beneath this site This understanding has been presented previously in both the RI

report and the FS and will be refined based on the TI SOW as necessary and summarized in the TI

Waiver Evaluation with specific attention to the physical and hydrogeological constraints on remediation

In particular the Site conceptual model will be reviewed in light of the new geologic data from drilling

logging and packer testing and the new hydrogeologic data obtained from the pumping test and tracer test

and will be revised to incorporate the new understanding

4 An evaluation of the restoration potential of the site This section will consist of a several components

It will present a systematic review of the technologies potentially capable of remediating the site given

the physical and hydrogeological constraints identified in the site model The newly acquired data will

provide an improved understanding of bedrock hydraulic properties that will allow a more Site-specific

evaluation of technologies The review of technologies will also include review of innovative

technologies and will evaluate whether existing remedial technologies or strategies would be capable of

achieving groundwater restoration at the site in a reasonable timeframe The section reference the FS and

will summarize the alternative remedies considered in the FS focusing on the ability of each to restore

groundwater in a reasonable timeframe It will also include a discussion of the selected hydraulic

containment system in light of the data gathered from the pumping test conducted in conjunction with the

TI SOW

Based on the Batch Flushing Model and using the agreed upon koc data from the RI as well as data from

this TI SOW including the f data collected as part of Subtask 4 a restoration timeframe analysis will be

conducted Following completion of the timeframe analysis and consideration of the results of drilling

rock and water analyses and pumping and tracer test a determination will be made regarding the Source

Area and the portion of the Non-Source Area VOC plume that will not attain ARARs in a reasonable

time

TISOW WOODARD amp CURRAN 21 September 302003 20564309

40 SCHEDULE

A proposed project schedule is included with this plan as Figure 4-1 This schedule is included for

discussion purposes and will be modified as necessary once the final scope of work as been approved by

all parties and the field work activities are coordinated with the subcontractors

TISOW WOODARD amp CURRAN 22 September 302003 20564309

ID

2

3

4

5

6

7 a i 10

11

12

13

14

15

16

17

16

19

20

21

22

24

25

26

27

26

29

30

31

32

Task Name

Project Meeting with EPA

Finalize SOW

Prepare Work Plans QAPP HASP Revision

Submit Work Plans for EPA Approval

Project Meeting with EPA

Revisions to work plans

Submit final work plans

Subcontractor Contracts

Project Meeting wEPA

Field Investigation

Site Mobilization

Install Borings

Borehole Geophysics

Packer Testing amp Collect GW Samples

Pumping Test

Tracer Test

Test setup

Injection

Monitoring

Data Reporting

InstallDevelop Wells

Data Evaluation

Prepare Data Package

Data Package Submittal to EPA

Draft Tl Evaluation Repon

Draft Tl Evaluation Report Submttal to EPA

EPA ReviewComment on Tl Evaluation ReF

Project Meeting wEPA

Revisions to Tl Evaluation Report

Submit Final Tl Evaluation Report

Start

Wed 070903

Thu 071003

Fri 101003

Mon 120103

Mon 121503

Mon 122903

Mon 011204

Tue 011304

Thu 021904

Fri 032104

Fri 032604

Fri 040204

Fri 041604

Fri 042304

Thu 050604

Wed 060204

Wed 060204

Wed 060904

Wed 060904

Wed 062304

Wed 070704

Wed 042804

Wed 062304

Mon 080204

Mon 070504

Tue 082404

Wed 082504

Wed 091504

Thu 0916AM

Thu 093004

Finish

Wed 070903

Fri 1OtO7u3

Fri 112803

Fri 122603

Mon 121503

Fri 010904

Mon 011204

Mon 012604

Thu 021904

Tue 071304

Thu 040104

Thu 042204

Tue 042704

Wed 050504

Tue 052504

Tue 071304

Tue 060804

Tue 061504

Tue 070604

Tue 071304

Fri 070904

Tue 072004

Fri 073004

Mon 080204

Mon 082304

Tue 082404

Tue 091404

Wed 091504

Wed 082904

Thu 093004

FIGURE 4-1 DRAFT HOWS CORNER SUPERFUND SITE

Tl EVALUATION amp RELD WORK FOR HYDRAUUC CONTAINMENT SYSTEM DESIGN PROPOSED PROJECT SCHEDULE

2003 2004 Mav |

Jun | Jul

ltamp i

Aug

i

Sen Oct I Nov Dec Jan Feb I Mar

ii i i

k ^tr 1

1V i

I t bull ^

I

ta^M bull bull M W

l LgtH^HBKLii LJ Mi

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50 ACRONYMS

AOC Administrative Order by Consent

ARARs Applicable or Relevant and Appropriate Requirements

ATV acoustic televiewer

bgs below ground surface

CERCLA Comprehensive Environmental Resource and Conservation Liability Act

DNAPL Dense Non-Aqueous Phase Liquid

GAC granular activated carbon

gpm gallons per minute

HASP Health and Safety Plan

row investigation-derived waste

MCL Maximum Containment Level

MEDEP Maine Department of Environmental Protection

MEG Maine Enforcement Guideline

mgkg milligrams per kilogram

Hg kg micrograms per kilogram

NCP National Contingency Plan

PCB polychlorinated biphenyl

PID photo ionization detector

ppm parts per million

PRP Potentially Responsible Party

TISOW WOODARD amp CURRAN 24 September 302003 20564309

50 ACRONYMS

AOC Administrative Order by Consent

ARARs Applicable or Relevant and Appropriate Requirements

ATV acoustic televiewer

bgs below ground surface

CERCLA Comprehensive Environmental Resource and Conservation Liability Act

DNAPL Dense Non-Aqueous Phase Liquid

GAC granular activated carbon

gpm gallons per minute

HASP Health and Safety Plan

row investigation-derived waste

MCL Maximum Containment Level

MEDEP Maine Department of Environmental Protection

MEG Maine Enforcement Guideline

mgkg milligrams per kilogram

Hg kg micrograms per kilogram

NCP National Contingency Plan

PCB polychlorinated biphenyl

PID photo ionization detector

ppm parts per million

PRP Potentially Responsible Party

TISOW WOODARD amp CURRAN 24 September 302003 20564309

QAPP Quality Assurance Project Plan

QAQC Quality AssuranceQuality Control

RA Remedial Action

RAO Remedial Action Objective

RCRA Resource Conservation and Recovery Act

RD Remedial Design

RIFS Remedial InvestigationFeasibility Study

ROD Record of Decision

SAP Sampling and Analysis Plan

SOW Statement of Work

TAL target analyte list

TI Technical Impracticability

USEPA United State Environmental Protection Agency

VOCs volatile organic compounds

WampC Woodard amp Curran Inc

TISOW WOODARD amp CURRAN 25 September 302003 20564309

REFERENCES

Everts CJ RS Kanwar (1994) Evaluation of Rhodamine WT as an adsorbed tracer in an agricultural

soil J Hydrology 153 53-70

Kasnavia T D Vu DA Sabatini (1999) Fluorescent dye and media properties affecting sorption and

tracer selection Groundwater 37 376-381

Ptak T G Schmid (1996) Dual-tracer transport experiments in a physically and chemically

heterogeneous porous aquifer effective transport parameters and spatial variability J Hydrology

183 117-138

Sabatini DA T A Austin (1991) Characteristics of Rhodamine WT and fluorescein as adsorbing

ground-water tracers Ground Water 29 341-349

Trudgill ST (1987) Soil water dye tracing with special reference to the use of Rhodamanie WT

Lissamine FF and Amino G acid Hydrological Processes 1 149-170

US Environmental Protection Agency (USEPA) 1993 Guidance for Evaluating the Technical

Impracticability of Ground-Water Restoration - Interim Final Office of Solid Waste and

Emergency Response Washington DC Directive 92342-25 September 1993

US Environmental Protection Agency (USEPA) 2002 Interim Record of Decision Summary shy

Operable Unit One Non-Source Area Groundwater West SiteHows Corner Superfund Site

Plymouth Maine EPA Region 1 September 2002

US Environmental Protection Agency (USEPA) 2003 Proposed Scope of Work West SiteHows

Corner Superfund Site Plymouth Maine EPA Region 1 4 pages September 2002

Vasudevan D RL Fimmen AB Francisco (2001) Tracer-grade Rhodamine WT Structure of

constituent isomers and their sorption behavior Environ Sci Technol 35 4089-4096

nsow WOODARD amp CURRAN 26 September 30 2003 20564309

Woodard amp Curran Inc (WampC) 2002 Final Feasibility Study Report - Non-Source Area Groundwater

Hows Comer Superfund Site Plymouth Maine July 2002

TISOW WOODARD amp CURRAN 27 September 302003 20564309

f

m WOODARD amp CURRAN Maine Massachusetts New Hampshire Connecticut Florida Illinois Operational offices across the US 1-800-426-4262 wwwwoodardcurrancom

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