M Mitc Obradovih c Assistant Director GRACE · GRACE M Mitc Obradovih c Assistant Director...

GRACE

M Mitch Obradovic

Assistant Director

Remediation Management Dept.

W R Grace & Co

6401 Poplar Avenue Suite 301

Tel (901)820-2065

Fax (901) 820-2061

Ct n cr

March 25, 1998

Mr. David LedererWaste Management DivisionU. S. Environmental Protection AgencyRegion I90 Canal StreetBoston, Massachusetts 02114

Mr. Edmond Benoit, Deputy Regional DirectorBureau of Waste Site CleanupMassachusetts Department ofEnvironmental Protection627 Main StreetWorcester, Massachusetts 01608

Subject: W. R. Grace & Co. - Conn. Acton Site Operable Unit Three

Gentlemen:

W. R. Grace & Co. - Conn. (Grace) submits herewith and agrees to execute the Operable UnitThree Remedial Investigation/Feasibility Study (RI/FS) Statement of Work (SOW) relating tothe Grace Site in Acton, Massachusetts (the Site) pursuant to the schedule set forth in theSOW, on the understanding that Grace and the Government Parties have mutually agreed toreserve their respective positions on the question of the governing statutory or other legalauthority.

In particular, Grace understands that the Government Parties take the position that theComprehensive Environmental Response, Compensation, and Liability Act of 1980, asamended (CERCLA), and the equivalent Massachusetts statute apply, which Grace disputes.Grace understands that the Government Parties dispute Grace's position that its obligationsare governed solely by the 1980 Consent Decree and the Amended MassachusettsDepartment of Environmental Protection (DEP) Order. Grace further understands that theGovernment Parties will not contend that Grace's agreement to the OU-3 RI/FS SOW in anyway operates as a waiver of Grace's position or an agreement on Grace's part to theGovernment Parties position.

Accordingly, and in reliance on the aforesaid mutual agreement and understandings, Gracedoes hereby reserve its right to contend that its obligations at the Site are governed solely bythe 1980 Consent Decree and the Amended DEP Order, and by agreeing to the SOW, Gracedoes not waive its position nor adopt or accept the Government Parties' position. For its part,Grace will not contend that the Government Parties' agreement to the SOW in any wayoperates as a waiver of the Government Parties' position or an agreement on their part toGrace's position.

Messrs. Ledererand Benoit 2~ March 25, 1998

By submitting the SOW for approval, Grace does not waive its position that any request for a revised report or plan is subject to the dispute resolution provisions of the 1980 Consent Decree. Grace acknowledges that the Government Parties reserve the right to take the position that CERCLA and/or M.G. L. c. 21E and associated implementing regulations govern disputes among the parties.

As was discussed at the March 28, 1997 meeting, it is Grace's intention to conduct the work called for by the SOW in accordance with the technical procedures and methodologies set out in the National Contingency Plan and the Massachusetts Contingency Plan, to the extent that those technical procedures and methodologies are not inconsistent with Grace's rights under the 1980 Consent Decree and the Amended DEP Order.

Grace's submission of the SOW is expressly conditioned upon receipt of written acknowledgment by the Government Parties of Grace's reservations set forth herein via a Government Party approval letter, substantially in accordance with the draft Government Party approval letter attached to the SOW as Attachment 4.

Very truly yours, s '

* *

" /t (L u-v/Ktv^ C

^ffi^ M. Mitch Obradovic " Assistant Director

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cc: William J. Cheeseman, Esq., Foley, Hoag & Eliot Andy Cohen, DEP Boston Jay Neparstek/DEP Boston J. Demming, Acton Water District Bob Eisengrein, ACES Jack Guswa, GeoTrans Doug Halley, Town of Acton Don Hanson, MADEP Stephen Anderson, Anderson and Kreiger Maryellen Johns, W. R. Grace & Co. Gretchen Muench, Esq., U.S. EPA Chuck Myette, EMCON Jim Okun, OT&O Bill Pencola, Foster Wheeler Mark Stoler, W. R. Grace & Co. (w/o attachment) R. Sugatt, Normandeau Associates J. Swallow/Pine & Swallow Associates W. Swanson, Camp Dresser & McKee File M-11.8

H \SHAREDVJJAMES\WORD\MMO\ACTONOU3 DOC

W. R. GRACE & CO. SITE, ACTON MA OPERABLE UNIT THREE

RI/FS STATEMENT OF WORK TABLE OF CONTENTS

SECTION 1: OBJECTIVES, REPORTING REQUIREMENTS, AND SCHEDULE 3 I. OBJECTIVES 3

A. Remedial Investigation 3 B. Feasibility Study Objectives 4

II. REPORTING REQUIREMENTS 4 III. SCHEDULE: STEPS AND DELIVERABLES 5

A. RI/FS Steps 5 B. RI/FS Deliverables 5 C. RI/FS Schedule 5

SECTION 2: SCOPING OF THE RI/FS 6 I. OBJECTIVES 6 II. DELIVERABLES 6

A. Overview 6 B. Project Operations Plan 7

1. Site Management Plan 8 2. Sampling and Analysis Plan (SAP) 9

2A. Quality Assurance Project Plan (OAPP) 10 2B. Field Sampling Plan (FSP) 13

3. Health and Safety Plan 15 4. Community Relations Support Plan (CRSP) 16

C. Applicable or Relevant and Appropriate Requirements 16 D. Data Requirements for Potential Remedial Alternatives and Technologies 22 E. Expanded Schedule for Remedial Investigation/Feasibility Study 23 F. Notification Requirements for New Releases and Threats of Release 23

SECTION 3: INITIAL SITE CHARACTERIZATION 24 I. OVERVIEW 24 II. DELIVERABLES 24

A. Initial Site Characterization Report 24 B. Work Plan for the RI/FS 24

SECTION 4: PHASE 1 RI/FS 25 I. OBJECTIVES 25 II. WORK PLAN REQUIREMENTS 26 III. COMPONENTS OF THE SITE CHARACTERIZATION 27

A. Site Survey 27

B. Subsurface and Hydrogeological Investigations 27 C. Surface Water and Sediments 29 D. Long-term Monitoring and Sampling 30 E. Treatability and Pilot Studies 31

IV. THE DEVELOPMENT AND INITIAL SCREENING OF ALTERNATIVES 31 A. Development of Alternatives 31 B. Initial Screening of Alternatives 33 C. Reporting 34

V. SCHEDULE AND DELIVERABLES 34 A. Draft RI Report 34 B. Development and Initial Screening of Alternatives Report 34 C. Work Plans 35

SECTION 5: POST-SCREENING FIELD INVESTIGATION 36 I. OBJECTIVES 36 II. DETAILED ANALYSIS OF ALTERNATIVES 36

A. Analysis 36 B. Reporting 37

III. DELIVERABLES FROM POST-SCREENING FIELD INVESTIGATIONS 37 A. Draft RI/FS 37 B. Work Plan 37

SECTION 6: Public Comment 38

ATTACHMENT 1 Ecological Risk Assessment Statement of Work ATTACHMENT 2 Public Health Risk Assessment Statement of Work ATTACHMENT 3 Letter from W.R.Grace & Co. to the Government Parties ATTACHMENT 4 Letter from the Government Parties to W.R. Grace & Co.

SECTION 1: OBJECTIVES, REPORTING REQUIREMENTS, AND SCHEDULE

I. OBJECTIVES

The Remedial Investigation and Feasibility Study (RI/FS) and associated Ecological Risk Assessment and Public Health Risk Assessment (Attachments 1 and 2, respectively) will be conducted to accomplish the objectives set out in the Consent Decree, the Amended DEP Order and the September 29,1989, Record of Decision (ROD) with respect to the third operable unit (OU Three) at the W.R. Grace & Co. Site in Acton, MA hi accordance with W.R. Grace & Co.-Conn.'s letter of March 25, 1998, Attachment 3 hereto, and a letter from the Environmental Protection Agency and the Department of Environmental Protection in substantially the form attached hereto as Attachment 4. The primary objective of the RI/FS shall be to evaluate the extent of groundwater contamination on and off site and to determine whether additional remedial measures are necessary to ensure accelerated restoration of the groundwater affected by the Site to a fully usable condition. The RI/FS will include an evaluation of the existing Aquifer Restoration System (ARS) to determine if it is adequately containing contaminated groundwater affected by the Site, and to establish target cleanup goals for groundwater that has been contaminated by the Site, based hi part on existing groundwater monitoring data from Operable Unit One. It will also include an evaluation of the nature and extent of surface water, sediment, and wetlands contamination that may be due to the presence of contaminated groundwater from the site as well as that resulting from past and continuing utilization of the Aquifer Restoration System (ARS) and to develop and evaluate, if necessary ,remedial alternatives for media other than groundwater that may be impacted by contaminated groundwater. The Site within context of this document is geographically meant to include all locations where groundwater impacts need to be evaluated on the property, and off the property as the result of migration from the property.

A. Remedial Investigation

The objectives of the RI are to:

1. Complete the definition of the extent of contaminants released to groundwater and the associated impacts on water, sediments and air at the Site (including the release of these contaminants from the Aquifer Restoration System); and

2. Provide sufficient information to determine whether additional remedial measures are necessary as described hi the Consent Decree and the DEP Amended Order and the 1989 ROD and if so to evaluate remedial alternatives (including treatment technologies), conceptually design remedial actions, select a remedy, and issue a Record of Decision.

The procedures used to address the objectives listed above include evaluating all existing Site information including data generated by W.R Grace & Co., EPA, the Commonwealth of Massachusetts, and their respective contractors; identifying data gaps; performing field sampling and laboratory analyses; conducting bench scale and/or field pilot studies; and consulting all available applicable, or relevant and appropriate human health and environmental regulations and/or laws. The RI shall include additional data gathering (samples, monitoring, and testing) to fill any identified data gaps, and developing methodology, procedures, and assessments for characterizing the nature and extent of groundwater contamination at or from the Site.

B. Feasibility Study Objectives

The objectives of the FS portion are, without limitation, to:

1. Review the applicability of various remedial technologies, including innovative technologies, to determine whether they are appropriate remedies for addressing groundwater and associated water, sediment and air contamination at the Site;

2. Determine if each alternative developed by combining groundwater remedial technologies is effective, by evaluating in the short and long term:

(a) effectiveness,

(b) implementability, and

(c) cost

3. Evaluate each alternative or combination of alternatives which survive the analysis of B.2. through a detailed and comparative analysis based upon the nine (9) criteria listed in the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (EPA 540/G-89/004 OSWER Dir. 9355.3-01 October 1988) and any criteria identified in the effective NCP (40 CFR Pan 300) or CERCLA as amended; and

4. Provide direction to the RI portions to ensure that sufficient data of the appropriate type exists to select a remedy based on the factors mentioned in the objectives listed above.

The FS includes, but is not limited to, conceptualizations, engineering analyses, cost analyses, and time frames for the achievement of clean-up goals.

II. REPORTING REQUIREMENTS

All data, methods, and interpretations must be:

A. Scientifically and technically sound with all assumptions, biases, potential deficiencies, safety factors, and design criteria explicitly stated;

B. discussed with observations and interpretation clearly identifiable and distinguishable;

C. discussed with all supporting reference material clearly identified and included or incorporated by specific reference to existing materials made available to the Government Parties;

D. concisely illustrated and presented in separate graphs, charts, maps, plans and/or cross-sections where possible so that the text provides a discussion of such illustrations;

E. linked to each and every objective for which they were completed and to which they are applicable; and

F. sufficient to satisfy the objectives of the RI and FS listed above.

III. SCHEDULE: STEPS AND DELIVERABLES

A. RI/FS Steps

W.R. Grace & Co. shall perform the RI/FS as discussed in this section and as shown in Table 1. The illustrated process is based on the current understanding of the Site. The integrated RI/FS process ensures an orderly selection of a remedy. If necessary, Site data needed to perform the FS shall be identified as early as possible in the RJ. However, the results of investigations during the RI/FS may require changes in the process.

B. RI/FS Deliverables

Deliverables for each step of the RI/FS are shown on Table 1. The actual number of deliverables may vary depending on:

1. the types of deliverables proposed by W.R. Grace & Co.;

2. tasks within RI/FS steps;

3. revisions based on GPs review;

4. requests for additional field studies, analyses, and documentation by the GPs or W.R. Grace & Co.; and

5. the quality and completeness of W.R. Grace & Co.'s work.

EPA and the Commonwealth of Massachusetts (the GPs) will review each major deliverable as described in the flowchart on Table 1. The GPs will consult with the Town of Acton, the Acton Water District, and the Acton Citizens for Environmental Safety (ACES). The GPs, however, retain the authority to approve or disapprove the deliverables.

C. RI/FS Schedule

Initiation of the schedule for W.R. Grace & Co. to complete the scoping of the RI/FS phase shall begin immediately. Initiation of the other phases of the RI/FS shall be triggered by notice from the GPs. The GPs may give notice to start a component of the study even if prior steps have not been completed.

In addition to appearing in this SOW, the schedule shall be included in the Work Plan for the RI/FS. It shall also accompany each of the major predetermined deliverables and monthly progress reports.

1 Table 1. Workflow of tasks included in the Operable Unit 3 RI/FS Draft SOW.

WORKFLOW FOR THE OPERABLE UNIT 3 RI/FS DRAFT SOW W R. GRACE - ACTON, MA

^ASE 1 RI/FS 5J,S

^-^IVERABLE

SITE CHARACTERIZATION REPORT (SUMMARY REPORT OF EXISTING DATA)

GP REVIEW AND COMMENT

WORKPLAN FOR PHASE 1 RI/FS PROJECT OPERATIONS PLAN

SITE MANAGEMENT PLAN

SAMPLING AND ANALYSIS PLAN (QUALITY ASSURANCE PROJECT PLAN and FIELD SAMPLING PLAN)

HEALTH AND SAFETY PLAN

COMMUNITY RELATIONS SUPPORT PLAN

APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARs) DATA REQUIREMENTS OF POTENTIAL REMEDIAL ALTERNATIVES AND TECHNOLOGIES

EXPANDED SCHEDULE FOR THE RI/FS

PHASE 1 ECOLOGICAL RISK ASSESSMENT WORKPLAN AND PROTOCOL

PUBLIC HEALTH RISK ASSESSMENT DELIVERABLES 1 AND 2


>rr.5£ / FIELD WORK

SITE SURVEY

SUBSURFACE AND HYDROGEOLOGICAL INVESTIGATION ^ v

SURFACE WATER AND SEDIMENTS

ECOLOGICAL ASSESSMENT

LONG-TERM MONITORING AND SAMPLING

TREATABILITY/PILOT STUDIES

DRAFT RI REPORT

PHASE I SCREENING ECOLOGICAL RISK ASSESSMENT (IF NECESSARY)


DEVELOPMENT AND INITIAL SCREENING OF ALTERNATIVES REPORT

DETAILED ANALYSIS OF ALTERNATIVES WORKPLAN

POST- SCREENING FIELD INVESTIGATION WORKPLAN (PHASE 2 RI/FS WORKPLAN)

PHASE 2 ECOLOGICAL RISK ASSESSMENT WORK PLAN (IF NECESSARY)


DUE DATE

120 days after approval of RI/FS SOW and attachments

60 days, unless GPs notify within that review period that more time will be required

90 days after GP approval of Site Characterization Report

Submitted with the Phase 1 Workplan

Submitted with the Phase 1 Workplan


As specified in approved Phase I RI/FS Work Plan

60 days after completion of Phase I Field Work

Submitted with Draft RI


90 days


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4

PHASE 2 RI/FS

DELIVERABLE

^_ E 2 FIELD WORK:

POST-SCREENING FIELD INVESTIGATION

PILOT STUDIES

ECOLOGICAL FIELD INVESTIGATION (IF NECESSARY)

ECOLOGICAL RISK ASSESSMENT REVISED DELIVERABLES 1 AND 2 (IF NECESSARY)

PHASE 2 PUBLIC HEALTH RISK ASSESSMENT REVISED PROTOCOL (IF NECESSARY)

DETAILED ANALYSIS OF ALTERNATIVES


PUBLIC HEALTH RISK ASSESSMENT DELIVERABLE 3


DRAFT Rl/FS

DRAFT BASELINE ECOLOGICAL RISK ASSESSMENT REPORT

XAFT BASELINE PUBLIC HEALTH RISK ASSESSMENT REPORT (DELIVERABLE 4)

WORKPLAN FOR SECOND DRAFT Rl/FS (IF NECESSARY)


SECOND DRAFT Rl/FS (IF NECESSARY)


PUBLIC COMMENT

FINAL DRAFT RI/FS

FINAL DRAFT BASELINE ECOLOGICAL RISK ASSESSMENT REPORT

FINAL DRAFT BASELINE PUBLIC HEALTH RISK ASSESSMENT REPORT (DELIVERABLE 5)

KEY TO THE TASKS WITHIN EACH PHASE OF THE RI/FS:

1 WORKPLAN

2. FIELD WORK

3. REPORT

4. GOVERNMENT PARTIES REVIEW AND COMMENT

I\N097W3181140970

DUE DATE

As specified in approved Phase 2 RI/FS Work Plan

Submitted after completion of Phase 2 Field Work

Submitted after completion of Phase 2 Field Work

To Be Determined


To Be Determined


To Be Determined

To Be Determined


To Be Determined


To Be Determined

To Be Determined

SECTION 2: SCOPING OF THE RI/FS

I. OBJECTIVES

The scoping of the RI/FS shall indicate that W.R. Grace & Co.:

A. understands the objectives of the RI/FS;

B. develops procedures to meet the RI/FS objectives, including those for field activities;

C. initiates the identification of federal or state Applicable or Relevant and Appropriate Requirements (ARARs);

D. assembles and evaluates existing data, identifies data gaps, and resolves inconsistencies;

E. develops a conceptual understanding of the Site based on the evaluation of existing data;

F. identifies likely response scenarios and potentially applicable technologies that may address Site problems;

G. identifies the type, quality and quantity of the data needed to assess possible adverse health and environmental effects and potential remedial technologies, to evaluate technologies that may be combined to form remedial alternatives, and to support decisions regarding remedial response activities;

H. prepares site-specific health and safety plans that shall specify, at a minimum, employee training and protective equipment, medical surveillance requirements, standard operation procedures, and a contingency plan that conforms with 29 CFR 1910;

I. develops sampling and analysis plans that shall provide a process for obtaining data of sufficient quality and quantity to satisfy data needs; and

J. provides a schedule which shows the flow of studies and the submission of deliverables.

II. DELIVERABLES

A. Overview

An Initial Site Characterization Report shall be provided by compiling existing data to describe current site conditions and apparent data gaps.

After the completion of the Initial Site Characterization Report. W.R. Grace & Co. shall deliver to the GPs the Workplan for the RI/FS which shall consist of the following in writing:

1. Project Operations Plan (POP);

2. Applicable or Relevant and Appropriate Requirements (ARARs);

3. Data Requirements of Potential Remedial Alternatives and Technologies; and

4. Expanded Schedule for the RI/FS.

Collectively, items 1-4 above are referred to as the Work Plan for the RI/FS in Table 1, and elsewhere in this document. The Work Plan for the RI/FS shall describe necessary studies to be done during the Phase 1 of the RI/FS. The Work Plan for the RI/FS shall be revised as necessary, and revisions submitted prior to each subsequent phase of work as described in Table 1.

To reduce the submittal of repetitive information contained within each of the elements of the Work Plan, W.R. Grace & Co. shall provide the appropriate cross-references at key places within each document. Documents used for past approved site activities may be used where appropriate.

B. Project Operations Plan

Before Phase 1 of the remedial investigation field activities, several site-specific plans shall be written to establish procedures to be followed by W.R. Grace & Co. in performing field, laboratory, and analysis work and community and agency liaison activities. These site-specific plans include the:

1) Site Management Plan;

2) Sampling and Analysis Plan (SAP) which includes the Field Sampling Plan (FSP) and the Quality Assurance Project Plan (QAPP);

3) Health and Safety Plan (HSP); and.

4) Community Relations Support Plan.

W.R. Grace & Co. shall combine these plans in preparing the Project Operations Plan (POP). As illustrated in Table 1, the POP is part of the Work Plan for the RI/FS. The POP must be approved pursuant to Section IV. of the Consent Decree and the DEP Amended Order before the RI field work can commence at the Site. The four components of the POP are discussed in the following Sections.

W.R. Grace & Co. shall modify the format and scope of each plan as needed to describe the sampling, analyses, and other activities that are clarified as the RI/FS progresses. These activities include on-site pilot studies of remedial treatments, laboratory bench scale studies, and subsequent rounds of field sampling.

7

1. Site Management Plan

The overall objective of the Site Management Plan is to provide the GPs with a written understanding of how various project aspects such as access, security, contingency procedures, management responsibilities, waste disposal, and data handling are being managed by W.R. Grace & Co. As part of the plan, W.R. Grace & Co. shall include, at a minimum:

a. a map and list of properties, the property owners, and addresses of owners to whose property access may be required;

b. a clear indication of any exclusion zone, contamination reduction zone, and clean area for off property activities;

c. necessary procedures and sample letters to land owners to arrange field activities and to ensure that the GPs are abreast of access-related problems and issues;

d. a provision for the security of government and private property on the Site;

e. the location of a field office for on-site activities;

f. contingency and notification plans for potentially dangerous activities associated with the RI/FS;

g. provision for the monitoring of airborne contaminants released by site activities which may affect local populations shall be provided in the Health & Safety Plan;

h. a provision for communicating to EPA, the State, and the public, details regarding the management of the RI/FS, including key personnel and their responsibilities;

i. a list of potential contractors and subcontractors of W.R. Grace & Co. in the RI/FS and a description of their activities and roles;

j. provision for the proper disposal of materials used and wastes generated during the RI/FS (e.g., drill cuttings, extracted ground water, protective clothing, disposable equipment). These provisions shall be consistent with the offsite disposal aspects of SARA, RCRA, and applicable state laws. W.R. Grace & Co., a representative of W.R. Grace & Co., or another party acceptable to the GPs shall be identified as the generator of wastes for the purpose of regulatory or policy compliance; and

k. plans and procedures for organizing, manipulating, and presenting the data generated and for verifying its quality before and during the RI/FS. To the degree possible, the data base management parameters shall be compatible with the EPA Region I and DEP data storage and analysis system.

2. Sampling and Analysis Plan (SAP')

The purpose of the Sampling and Analysis Plan is to ensure that sampling data collection activities will be comparable to and compatible with previous data collection activities performed at the site while providing a mechanism for planning and approving field activities.

The overall objectives of the sampling and analysis plan are as follows:

a. to document specific objectives, procedures, and rationales for field work and sample analytical work;

b. to provide a mechanism for planning and approving site and laboratory activities;

c. to ensure that sampling and analysis activities are necessary and sufficient; and

d. to provide a common point of reference for all parties to ensure the comparability and compatibility of all objectives and of sampling and analysis activities.

The SAP shall be the framework of all anticipated field activities (e.g., sampling objectives, evaluation of existing data, standard operating procedures) and contain specific information on the Phase 1 field work (e.g., sampling locations and rationale, sample numbers and rationale, analyses of samples). During the RI/FS, the SAP shall be revised as necessary to cover each round of field or laboratory activities. Revisions, or a statement regarding the need for revisions, shall be included in each deliverable describing new field work.

The SAP consists of two parts: (1) a Quality Assurance Project Plan (QAPP), and (2) the Field Sampling Plan (FSP). Components of these two individual plans are described in the following sections. In addition, the FSP and QAPP should be submitted as a single document (although they may be bound separately to facilitate use of the FSP in the field).

The SAP shall specify in the FSP provisions for notifying EPA and the DEP ten working days before initiation of field sampling or monitoring activities. The plan shall also allow split, replicate, or duplicate samples to be taken by EPA, DEP (or their contractor personnel), and by other parties as provided by the Consent Decree and the DEP Amended Order. At the request of EPA or DEP, W.R. Grace & Co. shall provide these samples in appropriate containers to the government representatives. Identical procedures shall be used to collect W.R. Grace & Co.'s, EPA's and DEP's parallel samples.

Guidance on the topics covered in the QAPP and FSP and their integration into each of these plans and the integration of the QAPP and the FSP into the SAP can be found in the following several references and shall be used to develop the SAP:

Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (OSWER Directive 9355.3-01, EPA/540/G-89/004, October 1988);

Data Quality Objectives for Remedial Response Activities Development Process (OSWER Directive 9355.0-7, EPA/540/G-87/003, March 1987);

Draft Data Quality Objectives for Remedial Response Activities. Example Scenario: RI/FS Activities at a Site with Contaminated Soil and Ground Water (OSWER Directive 9355.0-7B, EPA/540/G-87/002, March 1987); and

Test Methods for Evaluating Solid Waste. Physical/Chemical Methods (EPA Pub. SW846, Third Edition).

2A. Quality Assurance Project Plan (QAPP)

The Quality Assurance Project Plan (QAPP) shall document in writing site-specific objectives, policies, organizations, functional activities, and specific quality assurance/quality control activities designed to achieve the data quality objectives (DQOs) of the RI/FS. The QAPP shall cover all relevant environmentally related measurements. The QAPP developed for this project shall document quality control and quality assurance policies, procedures, routines, and specifications.

All project activities throughout the RI/FS shall comply with the QAPP. All QAPP sampling and analysis objectives and procedures shall be consistent with Interim Guidelines and Specifications for Preparing Quality Assurance Project Plans (EPA, 1983 - EPA/QAMS 005/80) and appropriate EPA handbooks, manuals, and guidelines including Test Methods for Evaluating Solid Waste. Physical/Chemical Methods (EPA Pub. SW-846, Third Edition, as amended by Update 1) and Guidelines Establishing Test Procedures for the Analysis of Pollutants (40 CFR, Part 136).

The 16 basic elements of the QAPP are:

1) title page with provision for approval signatures of principal investigators;

2) table of contents;

3) project description;

4) project organization and responsibility;

5) quality assurance objectives for measurement data, in terms of precision, accuracy, completeness, representativeness, and comparability;

6) sampling procedures;

7) sample custody;

8) calibration procedures and frequency;

9) analytical procedures, which must be EPA approved or equivalent methods;

10

10) data reduction, validation, and reporting;

11) internal quality control checks and frequency;

12) performance and system audits and frequency;

13) preventive maintenance procedures and schedules;

14) specific routine procedures to be used to assess the precision, accuracy, and completeness of data and to assess specific measurement parameters involved:

15) corrective action; and

16) quality assurance reports to management.

As indicated in EPA/QAMS-005/80, the above list of essential elements must be considered in the QAPP for the RI/FS. If a particular element is not relevant to a project and therefore excluded from the QAPP, specific and detailed reasons for exclusion must be provided.

Information in a plan other than the QAPP may be cross-referenced clearly in the QAPP provided that all objectives, procedures, and rationales in the documents are consistent, and the reference material fulfills the requirements of EPA/QAMS-005/80. Examples of how this cross reference might be accomplished can be found in the Data Quality Objectives for Remedial Response Activities (OSWER Directive 9355.0-7B) and the Data Quality Objectives for Remedial Response Activities. Example Scenario (OSWER Directive 9355.0-7B). EPA-approved references, or equivalent, or alternative methods approved by EPA shall be used, and their corresponding EPA-approved guidelines shall be applied when they are available and applicable.

Laboratory QA/QC Procedures

The QA/QC procedures for any laboratory used during the RI/FS shall be included in W.R. Grace & Co.'s QAPP. When this work is performed by a contractor to a private party, each laboratory performing chemical analyses shall meet the following requirements:

1) be approved by the State Laboratory Evaluation Program, if available;

2) have successful performance in one of EPA's National Proficiency Sample Programs (i.e., Water Supply or Water Pollution Studies or the State's proficiency sampling program);

3) be familiar with the requirements of 48 CFR Part 1546 contract requirements for quality assurance; and

4) have a QAPP for the laboratory including all relevant analysis. This plan shall be referenced as part of the contractor's QAPP.

11

Data Validation Procedures

W.R. Grace & Co. is required to certify that ten percent of the data has been validated by an independent person according to the Region I Laboratory Data Validation Functional Guidelines for Evaluating Organic Analyses and the Region I Laboratory Data Validation Functional Guidelines for Evaluating Inorganic Analyses (amended as necessary to account for the differences between the approved analytical methods for the project and the Contract Laboratory Procedures (CLP) procedures). Approved validation methods shall be contained in the QAPP.

The independent person shall not be the laboratory conducting the analyses and should be a person with a working knowledge of or prior experience with EPA data validation procedures. The independent person shall certify that the data has been validated, discrepancies have been resolved if possible, and the appropriate qualifiers have been provided.

W.R. Grace & Co. must keep the complete data package and make it available to the GPs on request in order for the GPs to conduct an independent validation of the data. The complete data package shall consist of all results, the raw data, and all relevant QA/QC information. An example set of data package deliverables is listed below.

1) a summary of positive results and detection limits of non-detects with all raw data;

2) tabulated surrogate recoveries and QC limits from methods 3500 and 8000 in SW846 and all validation and sample raw data;

3) tabulated matrix spike/matrix spike duplicate recoveries, relative percent differences, spike concentrations, and QC limits from methods 3500 and 8000 in SW-846 and all validation and sample raw data;

4) associated blanks (trip, equipment, and method) with accompanying raw data for tests;

5) tabulated initial and continuing calibration results (concentrations, calibration factors or relative response factors and mean relative response factors, % differences and % relative standard deviations) with accompanying raw data;

6) tabulated retention time windows for each column;

7) a record of the daily analytical scheme (run logbook, instrument logbook) which includes samples and standards order of analysis;

8) the chain of custody for the sample shipment groups, SAS packing slip, SAS request forms;

9) a narrative summary of method and any problems encountered during extraction or analysis;

12

10) tabulated sample weights, volumes, and % solids used in each sample calculation:

11) example calculations for positive values and detection limits; and

12) SW-846 method 3500 and 8000 validation data for all tests.

The forms contained in Chapter 1 of SW-846 (Second Edition 1982 as amended by Update I, April 1984, and Update II, April 1985) must be utilized to report the data when applicable. Raw data includes the associated chromatograms and the instrument printouts with area and height peak results. The peaks in all standards and samples must be labeled. The concentration of all standards analyzed with the amount injected must be included.

2B. Field Sampling Plan (FSP)

The objective of the Field Sampling Plan is to provide the GPs and all parties involved with the collection and use of field data with a common written understanding of all fieldwork. The FSP shall address the RI/FS objectives and conform to the procedures in Section 2 of this document and the National Contingency Plan (NCP).

The FSP shall define in detail the sampling and data gathering methods used on a project. The FSP should be written so that a field sampling team unfamiliar with the Site would be able to gather the samples and field information required. Guidance for the selection of field methods, sampling procedures, and custody can be acquired from the Compendium of Superfund Field Operations Methods. (OSWER Directive 9355.0-12, EPA/540/P-87/001), which is a compilation of demonstrated field techniques that have been used during remedial response activities at hazardous waste sites.

The FSP shall be site-specific and shall include the following information:

Site Background The analysis of the existing Site details must be included in the FSP. This analysis shall include a conceptual Site model. A conceptual Site model includes a description of the Site and surrounding areas and a discussion of known and suspected contaminant sources, probable transport pathways, and other information about the Site. The FSP shall also include descriptions of specific data gaps and ways in which sampling is designed to fill those gaps.

Sampling Objectives Specific objectives of a sampling effort that describe the intended uses of data must be clearly and succinctly stated.

Sample Location, Analytes. and Frequency This section of the sampling plan identifies each sample matrix to be collected and the constituents to be analyzed. Tables shall be used to clearly identify the number of samples to be collected along with the appropriate number of replicates and blanks. Figures shall be included to show the locations of existing or proposed sample points.

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Sample Designation A sample numbering system shall be established. The sample designation should include the sample or well number, the sample round, the sample matrix (e.g., surface soil, ground water, soil boring), and the name of the Site.

Sampling Equipment and Procedures Sampling procedures must be clearly written. Step-by-step instructions for each type of sampling are necessary to enable the field team to gather data that shall meet the Data Quality Objectives (DQOs). A list should include the equipment to be used and the material composition (e.g., Teflon, stainless steel) of equipment along with decontamination procedures.

Sampling Handling and Analysis A table shall be included that identifies sample preservation methods, types of sampling jars, shipping requirements, and holding times. Examples of paperwork such as traffic reports, chain of custody forms, packing slips, and sample tags filled out for each sample as well as instructions for filling out the paperwork must be included. Field documentation methods including field notebooks and photographs shall be described.

Each Field Sampling Plan submitted as a part of the Work Plan for the RI/FS shall be sufficiently detailed to carry out the study, and shall provide data needed to fully address the objective of the study and to complete the study. Each study shall be designed to achieve a high performance on the first attempt. Each work plan shall be related (by cross-references) to the other requirements in the Project Operations Plan.

In the Field Sampling Plan for the RI/FS (Phase 1), W.R. Grace & Co. shall include plans that describe how each of the following and other necessary studies shall be done. See Section 4 of this document to facilitate understanding of the type and quality of the deliverable required for each activity of the Phase 1 RI.

1) site survey;

2) subsurface and hydrogeological factors;

3) surface water and sediment sampling;

4) long-term monitoring and sampling;

5) treatability and pilot studies; and

6) biota sampling.

The complete results of these studies shall be described in the draft RI Report. The data from these studies and the Initial Site Characterization Report shall be submitted according to the schedule (Table I of this document).

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3. Health and Safety Plan

The objective of the site-specific Health and Safety Plan (HSP) is to establish the procedures, personnel responsibilities, and training necessary to protect the health or safety of all on-site personnel during the RI/FS. The plan shall provide for routine but hazardous field activities and for unexpected Site emergencies.

The site-specific health or safety requirements and procedures in the HSP shall be based on an ongoing assessment of Site conditions, including the most current information on each medium. For each field task during the RI/FS, the HSP shall identify:

a. possible problems and hazards and their solutions;

b. environmental surveillance measures;

c. specifications for protective clothing;

d. the appropriate level of respiratory protection;

e. the rationale for selecting that level; and

f. criteria, procedures, and mechanisms for upgrading the level of protection and for suspending activity, if necessary.

The HSP shall also include the delineation of exclusion areas on a drawing and describe provisions for this delineation in the field. The HSP shall indicate the on-site person responsible for implementing the HSP as a representative of W.R. Grace & Co., protective equipment, personnel decontamination procedures, and medical surveillance. The following documents shall be consulted:

Interim Standard Operations Safety Guides. (Hazardous Response Support Division, Office of Emergency and Remedial Response EPA, Wash. D.C. 1982);

Hazardous Waste Operations and Emergency Response. (Department of Labor, Occupational Safety and Health Administration, (OSHA) 29 CFR Part 1910); and

Occupational Safety and Health Guidance Manual for Hazardous Waste Site Activities: Appendix B. (NIOSH/OSHA/USCG/EPA 1985).

OSHA regulations at 40 CFR 1910 and Chapter 9 of the Interim Standard Operating Safety Guide, which describes the routine emergency provisions of a site-specific health and safety plan, shall be the primary reference used by W.R. Grace & Co. in developing and implementing the Health and Safety Plan.

The measures in the HSP shall be developed and implemented to ensure compliance with all applicable State and Federal occupational health and safety regulations. The HSP shall be consistent with the objectives and contents of all other plans submitted by W.R. Grace & Co.. The HSP shall be updated as necessary.

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4. Community Relations Support Plan (CRSP)

W.R. Grace & Co. shall develop a Community Relations Support Plan, whose objective is to ensure and specify adequate support from W.R. Grace & Co. for the community relations efforts of the GPs. Currently, the GPs do not envision changes to the CRSP prepared by the GPs in December 1991. This support shall be at the request of the GPs or as required by Grace under the CRSP and may include, at a minimum:

a. participation in public informational or technical meetings, including the provision of visual aids and equipment;

b. publication and copying of fact sheets or updates; and

c. assistance in preparing a responsiveness summary after the RI/FS public comment period.

C. Applicable or Relevant and Appropriate Requirements

W.R. Grace & Co. shall identify all probable Federal Applicable or Relevant and Appropriate Requirements (ARARs), identify State ARARs and identify any local requirements. Applicable requirements are those cleanup standards, standards of control, and other substantive requirements, criteria, or limitations promulgated under Federal environmental or State environmental or facility siting laws that specifically address a hazardous substance, pollutant, contaminant, remedial action, location, or other circumstances at a CERCLA site. Relevant and appropriate requirements are those cleanup standards, standards of control, and other substantive requirements, criteria, or limitations promulgated under Federal or State environmental or facility siting laws that. while not applicable to a hazardous substance, pollutant, contaminant, remedial action, location, or other circumstances at a CERCLA site, address problems or situations sufficiently similar to those encountered at the CERCLA Site that their use is well suited to the particular site.

In addition to ARARs, W.R. Grace & Co. shall also make preliminary determinations on the extent that other publicly available criteria, advisories, and guidances are pertinent to the hazardous substances, possible work conducted at specific locations at the Site, and potential remedial actions. ARARs and other criteria, advisories, and guidances shall be:

1. considered in terms of their chemical-specific, location-specific, and action-specific attributes;

2. evaluated for each medium (surface water, groundwater, sediment, air, biota, and facilities) particularly for chemical-specific ARARs, but including other ARARs as appropriate;

3. distinguished for each technology considered, particularly for action-specific ARARs, but including other ARARs as appropriate; and

4. considered at each major step of the RI/FS where they are indicated.

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In general, identification of chemical and location specific ARARs is more important in the beginning steps of the RI/FS, whereas the identification of action-specific ARARs gain importance later, during the more FS-oriented steps. If a requirement is determined to be not applicable, W.R. Grace & Co. shall subsequently consider whether it is relevant and appropriate. When any new site-specific information becomes available, ARARs should be re-examined.

Chemical-specific ARARs are usually health or risk-based numerical limits on the amount of, or concentration of, a chemical that may be found in, or discharged to the ambient environment. The Maximum Contaminant Levels (MCLs) of the Safe Drinking Water Act (SDWA, 1986), the Federal Ambient Water Quality Criteria of the Clean Water Act adopted in the Commonwealth of Massachusetts water quality standards are examples of chemical-specific ARARs. Additive risks shall be evaluated and, if appropriate, shall be utilized as a remediation goal.

Location-specific ARARs are general restrictions placed upon the concentration of hazardous substances or the conduct of activities solely because they are in specific locations. Some examples of specific locations include, but are not limited to floodplains, wetlands, historic places, places with objects of archaeological significance, and sensitive ecosystems or habitats. A few examples of possible location-specific ARARs are the Floodplain Management Executive Order (Federal Register, 1977a - E.O. 11988). the Protection of Wetlands Executive Order (Federal Register. 1977 - E.O. 11990), and the regulations promulgated pursuant to the National Historic Preservation Act of 1966 and any and all of its subsequent amendments.

Action-specific ARARs are usually technology-based or activity-based directions or limitations which control actions taken at CERCLA sites. Action-specific ARARs, as the name implies, govern the remedial actions. RCRA 40 CFR Part 264, Subpart G Closure Regulations, RCRA 40 CFR Part 264, Subpart 0 Incineration Regulations, and the land disposal restrictions set forth by the Hazardous and Solid Waste Amendments Act of 1984 are a few examples of possible action-specific ARARs.

As part of the Work Plan for the RI/FS, W.R. Grace & Co. shall provide a list in the form of a chart of ARARs and publicly available EPA/State of Massachusetts criteria, advisories, and guidances, and limitations which should initially be exhaustive of all such requirements. The description shall briefly describe the requirements and shall include: if it is a numerical requirement; what it is based upon (i.e., health, technical practicality); and what media it is designed for (i.e., surface water, ambient air, etc.). The list shall indicate whether each requirement is: potentially applicable or relevant and appropriate; chemical-specific, location-specific, or action-specific; pertinent to surface water, ground water, soil, air, biota, or facilities; and affixed with specific levels or goals to be attained. If specific levels or goals are affixed, they must be enumerated in the chart.

Data requirements in terms of physical and chemical characteristics needed to evaluate ARARs shall be considered as part of the scoping. Such requirements may include but are not limited to chemical residuals, background levels, or various modeling parameters. Such data requirements shall be satisfied during Phase 1 of the RI to the extent possible, rather than during the later phases of the RI/FS. W.R. Grace & Co. shall identify

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attributes necessary to achieve specific levels or goals, and include appropriate procedures in the Phase 1 RI discussed in Section 4.

The following shall be consulted during the ARAR identification process:

CERCLA Compliance with Other Laws Manual: Draft Guidance (August 1988, EPA/540/G-89/006).

CERCLA Compliance with Other Laws Manual: Part II. Clean Air Act and Other Environmental Statutes and State Requirements (August 1989. EPA/540/G-89/009).

Section 4 of Guidance of Feasibility Studies Under CERCLA (EPA, 1985c - EPA/540/G85/003), and Appendix E of the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (EPA/540/G-89/004,OSWER Directive 9355.3-01, EPA October 1988) present a partial list of potential ARARs. Additional ARARs must be sought by W.R. Grace & Co. during a thorough search of applicable Federal and State environmental statutes and regulations.

W.R. Grace & Co. shall identify all site-specific ARARs. At a minimum, chemical- and location-specific ARARs shall be identified as part of the Initial Site Characterization, and the action-specific ARARs shall be identified after the Development and Initial Screening of the Remedial Alternatives. Sufficient justifications for incorporating or dropping a requirement shall be provided at each step where such decisions are made.

The following paragraphs partially list potential ARARs for the Site. The list is not complete because the major investigative effort at the Site has not been performed. However, the list shall be used to focus tasks during the RI/FS.

Safe Drinking Water Act

National Primary Drinking Water Standards, Maximum Contaminant Levels (40 CFR 141): The maximum level of a contaminant in water which is delivered to the free flowing outlet of the ultimate user of a public water system.

Maximum Contaminant Level Goals (40 CFR 141): The maximum contaminant level in drinking water at which no known or anticipated adverse effect on the health of persons would occur, and which allows an adequate margin of safety.

Underground Injection (40 CFR 144): These standards may be applicable if underground injection is chosen as a remediation technology. These standards require compliance with certain administrative and procedural sections of 40 CFR 265 Subpart R.

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Clean Water Act

A NPDES permit may be required if the remedy includes discharging to surface water offsite. If the discharge is on-site, the substantiative requirements of the Clean Water Act regulations must be met. Effluent limitations developed must meet both the technological (BAT, BPT, BCT) requirements of the Clean Water Act, as well as assure compliance with the Massachusetts Surface Water Quality Standards and the water quality criteria contained therein.

Toxic Pollutant Effluent Standards (40 CFR 129): The concentration of a toxic pollutant in navigable waters that shall not result in adverse impact on important aquatic life, or on consumers of aquatic life, after exposure of that aquatic life to the pollutant for periods of time exceeding ninety-six (96) hours and continuing through at least one reproductive cycle.

Resource Conservation and Recovery Act

In general, the applicable solid waste requirements shall be action-specific, applying to the remedial activities undertaken. The following are some examples of RCRA requirements (40 CFR 264) that may be Applicable or Relevant and Appropriate:

Chemical, Physical, and Biological Treatment: Although standards do not yet exist for general waste treatment in new facilities, standards do exist for interim status facilities (40 CFR 265, Subpart Q) and include specific requirements for ignitable and reactive wastes. The interim status requirements are probably not applicable if the treatment is performed on-site, but they may be relevant and appropriate.

Thermal Treatment: Standards do not yet exist for thermal treatment in new facilities, but standards do exist for interim status facilities (40 CFR 265, Subpart P) and provide for general operating requirements, waste analysis, monitoring and inspections, closure, open burning, and waste explosives. The interim status requirements are probably not applicable if the treatment is performed on-site, but they may be relevant and appropriate.

Storage (40 CFR 264, Subparts I and J): Two subparts include standards for storage of hazardous waste in containers (Subpart I) and tanks (Subpart J). In addition, sections of Subparts B and C also relate to storage.

Onsite Land Disposal (40 CFR 264, Subparts L, M, and N): Land disposal techniques will probably not be chosen given SARA's preference for permanent remedies that reduce the volume, mobility, and toxicity of hazardous substances. However, requirements for landfills are in Subpart N, and requirements for general landfill treatment (biodegradation, volatilization, land farming) are in Subpart M. Another form of land treatment is underground injection, which is discussed above (40 CFR 144)

Ground-Water Monitoring (40 CFR 264, Subpart F): This subpart provides RCRA ground-water corrective action requirements that may be applicable or relevant and appropriate at the Site. These requirements include ground-water monitoring and groundwater protection standards.

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Other potential ARARs are:

A. Ground-water classification for aquifers underlying the Site;

B. Regulations pertaining to activities that affect the navigation of waters of the United States (33 CFR 320-329);

C. Endangered Species Act (50 CFR 81, 225, 402);

D. Fish and Wildlife Coordination Act (50 CFR 83);

Commonwealth of Massachusetts Potential ARARs

1. M.G.L.C.21C and the Massachusetts Hazardous Waste Regulations, 31OCMR 30.000

A. Management Standards for Hazardous Waste Facilities, 310 CMR 30.500

B. Site Security Standards, 310 CMR 30.514

C. Closure Regulations, 310 CMR 30.580

D. Post-Closure Regulations, 310 CMR 30.590

E. Technical Standards for Hazardous Waste Facilities, 310 CMR 30.600 - 30.690

i. Closure and Post Closure Care for Surface Impoundment Regulations, 310 CMR 30.617

ii. Groundwater Protection Regulations, 310 CMR 30.661 -30.763 (collectively cited as 310 CMR 30.660)

F. Land Disposal Restrictions. 310 CMR 30.750

G. EP Toxicity and Toxicity Characteristics, at 310 CMR 30.125A, 30.125B and 40 CFR 261 et. seq.

H. PCB Regulations, 310 CMR 30.105, 310 CMR 30.370, 40 CFR 761

2. c.21D and the Massachusetts Hazardous Waste Facility Siting Regulations, 990 CMR 5.04

3. S. 17, M.G.L. c. 111, s. 160 and the Massachusetts Drinking Water Regulations at 310 CMR 22.00

4. s. 27 and 43, DWPC Surface Water Discharge Permit Program Massachusetts NPDES, 314 CMR 3.00

5. s. 27, DWPC Surface Water Quality Standards 314 CMR 4.00.

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6. c.21, ss. 43 and 44, DWPC Ground Water Discharge Permit Program. 314 CMR 5.00

7. c.21. ss. 27(5), 27(6) and 27(12), DWPC Groundwater Quality Standards, 314 CMR 6.00

8. ss. 27(9), 27(12), and 34, Operation and Maintenance and Pretreatment Standards for Wastewater Treatment Works, 314 CMR 12.000

9. ss. 142A-142J, Ambient Air Quality Standards, 310 CMR 6.000 - 310 CMR 8.000

10. s. 40 and the Wetland Protection Regulations at 310 CMR 10.00.

11. ss. 26-53, Certification for Dredging, Dredge Material and Filling in Water at 314 CMR 9.00.

12. s. 4, clause 13 A, Endangered, Threatened, and Special Species of Concern, 321 CMR 8.00 and the Massachusetts Natural Heritage Program

Commonwealth of Massachusetts To Be Considered

1. "Guide to the Regulation of Toxic Chemicals in Massachusetts Waters".

2. "Standard References for Monitoring Wells", DEP Publication #WSC-310-91. 4.91, includes 7/94 Sections 7 & 8 update.

3. "Off-Gas Treatment of Point-Source Remedial Air Emissions". DEP Publication #WSC94-150. (5/94).

4. "Minimum Standards for Analytical Data for Remedial Response Actions Under M.G.L.C.21E", Policy WSC-89-004/WSC-300-89.

5. "Policy on the Identification of Hazardous Waste", HW-85-004.

6. BRP/BWSC Memorandum of Understanding and Unfeasibility Criteria.

7. "A Guide on Remedial Actions at Superfund Sites with PCB Contamination", EPA Directive # 9355.4-01FS.

8. Threshold Effects Exposure Limits (TEL) values and annual average Allowable Ambient Limits (AAL) values.

9. "Interpretation of Identified Vegetation", Wetlands Protection Program Policy 85-1.

10. "Isolated Land Subject to Flooding", Wetlands Protection Program Policy 85- 2.

11. Presumptions for Subsurface Sewage Disposal Systems that Meet Title 5", Wetlands Protection Program Policy 86-1.

12. "Expedited Reviews", Wetlands Protection Program Policy 87-1. 21

13. "Aquatic Plant Control", Wetlands Protection Program Interim Guidance 90- TGI.

14. "Rare Species Habitat", Wetlands Protection Program Policy 90-2.

15. "Quality Assurance for Groundwater Modeling", DWS Policy 87-12.

16. "The Determination and Management of the Protective Radius (Zone 1) for Public Supply Wells", DWS Policy 87-20.

17. "Interim Wellhead Protection Area", DWS Policy 88-03. April 15, 1988.

18. "Watershed Resource Protection Plan Policy", DWS Policy 89-09. January 19, 1990.

19. "Guidelines and Policies for Public Water Systems - August 1996 Edition", DEP Division of Water Supply

20. "Massachusetts Drinking Water Standards and Guidelines" (May 1996), DEP/ORS.

D. Data Requirements for Potential Remedial Alternatives and Technologies

Potential Remedial Action objectives shall be identified for groundwater and other media that may be impacted by contaminated groundwater and treated groundwater, and a preliminary range of remedial action alternatives and associated technologies shall be identified. W.R. Grace & Co. shall identify, consistent with the National Contingency Plan and applicable guidance, all potential remedies that may be useful in remediating contaminated groundwater and other media that may be impacted by contaminated groundwater and/or treated groundwater. In discussing potential remedies, EPA describes an alternative as a group of technologies, including innovative ones, that will achieve certain remedial action goals (see Section 4). W.R. Grace & Co. shall identify the various technologies, showing the critical data needed to evaluate such technologies, and the performance of technologies grouped into an alternative. These data requirements shall be initially developed during the Work Plan for the RI/FS and shall be further incorporated in all subsequent field investigation Work Plans. The data shall be obtained during the Phase 1 RI (see Section 4) and shall be further refined during the Post-Screening Field Investigation (see Section 5).

The identification of potential technologies shall help ensure that data needed to evaluate the technologies are collected in the Phase 1 field investigations. Certain parameters may be common to several possible technologies and alternatives.

In addition to the common data requirements, any other data necessary to evaluate a particular technology or alternative leading to remedy selection shall be noted in the Work Plan and subsequently integrated into each field investigation. The EPA Guidance on Conducting Remedial Investigations and Feasibility Studies Under CERCLA, (EPA/540/G-89/004, OSWER Directive 9355.3-01, EPA October 1988) shall be a source of additional information on identifying alternative remedies and potential innovative technologies.

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A preliminary list of broadly defined alternatives shall be developed by W.R. Grace & Co.. Consistent with Sections 4 and 5 of this document, this list shall include a range of alternatives in which treatment that significantly reduces the toxicity, mobility, or volume of waste is a principal element; one or more alternatives that involve containment with little or no treatment; and a no-action alternative. W.R. Grace & Co. shall present a chart, or a series of charts, showing the requirements and technologies to be considered for remedial alternatives. In the charts, data requirements shall be linked to the Work Plans for each field investigation.

E. Expanded Schedule for Remedial Investigation/Feasibility Study

The major predetermined deliverables are identified in Table 1. The established schedule along with a more detailed, expanded schedule for subtasks shall be included as a component of the Work Plan for the RJ/FS. Modifications of the schedule must be approved by the GPs prior to their implementation.

The schedule shall be presented as a chart, which shall include target data and time periods for each deliverable, to the extent possible. The chart shall be updated when the schedule changes by showing the original (planned) due date and revisions of the due date.

A copy of the schedule shall be in the preface of each major deliverable of the RI/FS and in each monthly progress report required by the RI/FS agreement.

F. Notification Requirements for New Releases and Threats of Release

Attention should also be given to compliance with notification and other requirements of Chapter 21E and the Massachusetts Contingency Plan applicable to new releases and threats of release at the Site. Pertinent regulations include, without limitation, 310 CMR 40.0300-40.0314 (covering releases and threats of release which require 2-hour and 72hour notification) and 310 CMR 40.0330 (covering notification requirements and procedures).

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SECTION 3: INITIAL SITE CHARACTERIZATION

I. OVERVIEW

The objective of the Initial Site Characterization is to summarize the existing data in order to evaluate the current nature and extent of groundwater contamination at the Site. Areas of the Site which require further investigations will be identified and additional work to fill these data gaps will be described in the Phase 1 RI Workplan. The Initial Site Characterization will also evaluate the effectiveness of the Aquifer Restoration System(ARS) to contain and remediate groundwater affected by the Site.

The Initial Site Characterization Report will consist of tables, graphs, maps, and text sections which will allow water quality and water level data collected since 1985 to be more readily examined and evaluated. Water quality data collected from groundwater monitoring wells and the groundwater treatment system and water level data will be used to evaluate areas of the Site where Maximum Contaminant Levels (MCLs) are exceeded or where insufficient data exists to determine the nature and extent of contamination. The current database that has been compiled for the Site will allow W.R. Grace & Co. to prepare a comprehensive evaluation of the existing groundwater recovery and treatment system.

II. DELIVERABLES

A. Initial Site Characterization Report

B. Work Plan for the RI/FS

W.R. Grace & Co. shall submit a Work Plan for the RI/FS as a Site Characterization Deliverable.

During the Site Characterization, it is anticipated that the need for additional information will become apparent. W.R. Grace & Co. shall prepare a Work Plan for the RI/FS that describes the data to be obtained. W.R. Grace & Co. shall submit the Work Plan to the GPs for review as a Site Characterization Deliverable, and shall perform the necessary studies after receiving a notice to proceed with Phase 1 Field Work by the GPs. The Work Plan for the RI/FS shall be scoped to meet all field data collection objectives of the RI/FS (Section 1), be consistent with the procedures in the Project Operations Plan (Section 2), and fulfill the requirements of the Phase 1 RI (Section 4).

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SECTION 4: PHASE 1 RI/FS

I. OBJECTIVES

At its onset, the goal of the Phase 1 RI shall be to collect all field data which can reasonably be assumed to be necessary for the Remedial Investigation (RI) and Feasibility Study (FS) and sufficient to select a remedy. The Phase 1 RI shall conform to the work plans for the characterization, written in the Work Plan for the RI/FS and included in the Field Sampling Plan. W.R. Grace & Co. shall characterize and/or describe the following, at a minimum:

1. amount, concentration, toxicity, environmental fate, transport (e.g., bioaccumulation, persistence, mobility), phase (e.g., solid, liquid), and other significant characteristics of each hazardous substance present;

2. zones between media, and critical parameters for decontamination (e.g., soil chemistry, soil types, porosity);

3. hydrogeologic factors (e.g., depth to groundwater table, hydraulic gradients, hydraulic conductivity, proximity to residential wells, flood plains, and wetlands);

4. climate and water table fluctuation (e.g., precipitation, run-off, stream flow, water budget);

5. routes of exposure and receptors;

6. populations and environmental concerns, including biological communities and habitats on or abutting the Site;

7. extent to which the hazardous substances have migrated or are expected to migrate;

8. contribution to the contamination of air, land, groundwater, surface water, sediment, and the food chain;

9. surface water classifications and existing use designations;

10. ground-water characteristics and current and potential ground-water uses (e.g., characteristics related to the ground-water classes described in the Ground Water Protection Strategy. (EPA, 1984));

11. extent to which contamination levels exceed health-based levels prompting a necessary response action;

12. waste characteristics that affect the type of treatment possible (e.g., BTU values, pH, BOD);

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13. extent to which substances at the Site may be reused or recycled:

14. Current extent of substances or residuals remaining onsite, as well as the potential extent of future releases from such sources;

15. physical characteristics of the Site, including important surface features, soils, geology, hydrogeology, meteorology, and ecology;

16. characteristics or classifications of surface water and ground water;

17. other factors, such as sensitive populations, that pertain to the characterization of the Site or support the analysis of potential remedial action alternatives; and

Using this information, W.R. Grace & Co. shall further define the boundaries of the RI/FS study area by determining the extent of existing contaminants and of environmental effects resulting from releases from the Site. The Phase 1 RI shall provide information sufficient to refine the preliminary identification of potentially feasible remedial technologies, ARARs, and the data needed by the Grace to perform the Baseline Risk Assessment.

In the Phase 1 RI, W.R. Grace & Co. shall gather additional field data necessary to fulfill the requirements of the following deliverables:

1. Draft Remedial Investigation Report;

2. Development and Initial Screening of Alternatives Report;

3. Detailed Analysis of Alternatives Work Plan; and

4. Post-Screening Field Investigation Work Plan.

The RI includes a set of field investigations. Data gaps exposed in the Initial Site Characterization and further data requirements from the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (EPA/540/G-89/004, OSWER Directive 9355.3-01, October 1988), the National Contingency Plan, and the previous three sections of this Statement of Work shall provide the focus for the studies.

II. WORK PLAN REQUIREMENTS

The Phase 1 RI shall specifically consist of the activities and deliverables described in this section (Section 4).

For each component of the site characterization, W.R. Grace & Co. shall establish, at a minimum, and include in the Work Plan for the RI/FS the following:

1. A description of the locations of suspected contaminated areas and the areas considered to represent background levels;

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2. An anticipated number or schedule of samples, subject to the results of field activities;

3. Quality assurance/quality control procedures, including blanks, duplicates, alternative analysis conditions, and standards;

4. A method for determining how the field program shall be adjusted according to the initial sampling results; and

5. The analytical methodology to be used for each medium including instrumentation and detection limits.

III. COMPONENTS OF THE SITE CHARACTERIZATION

A. Site Survey

The Site map provided using updated previous surveys shall have 2-foot elevation contours and shall display survey data collected at the Site. The map shall contain all standard topographic, physiographic, cultural, and facility features, the surveyed locations of all wells (including residential wells), and surface sampling locations.

W.R. Grace & Co. shall prepare maps of smaller scale that show offsite sampling locations and the courses of contaminants. The basis of one of these maps shall be the U.S. Geological Survey 7.5-minute quadrangle which includes the Site.

W.R. Grace & Co. shall determine the elevations and horizontal locations of all wells, piezometer, and other sampling locations. It may be necessary to extend the Site map based on the results of the Site characterization. The Site survey shall be of sufficient detail for explanations of areas into which contaminants may migrate.

B. Subsurface and Hydrogeological Investigations

1. Objectives

W.R. Grace & Co. shall plan, conduct, and report subsurface and hydrogeological investigations sufficient to characterize and/or describe, at a minimum, the following:

a. the nature and extent of contamination sufficiently to define the boundaries of all contaminant plumes and to quantify in three dimensions every aquifer, including bedrock;

b. a quantitative estimate of the number of years necessary to achieve clean-up goals for groundwater extraction and treatment remedial alternatives;

c. the subsurface stratigraphy and structure, for each rock and soil type including, but not limited to, lithologies, grain sizes, sorting, permeability, fracturing (orientation, frequency, and effects), plasticity index, moisture content, dry density, and mineralogy;

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d. the concentration, environmental fate, transport mechanisms, and other significant characteristics of each contaminant;

e. the partitioning of contaminants between groundwater and soil or rock, and determine the phases, including their partitioning coefficients:

f. quantification of the hydrogeological factors (e.g., in situ permeability, conductivity, and storage capacity of each soil and rock type; depth of saturated zone; hydraulic and pressure gradients);

g. the routes of groundwater migration, transport rates, and receptors. Also specifically determine the locations, flow rates, contaminant concentrations, and variability for discharge to bodies of surface water;

h. the seasonal fluctuations in the water table, flow gradients, and contaminant concentrations, simultaneously with other factors such as precipitation, run-off, and stream flow;

i. the condition of existing monitoring wells and the need to replace them or a portion of their installation materials;

j. the construction, location, and proximity, of residential, municipal, and previously installed monitoring wells;

k. the populations and environments at risk;

1. the extent to which the hazardous substances will migrate once the limits of plumes are determined (if modeling studies are involved, the parameters, assumptions, accuracy, contingencies of the studies must be explicitly stated, and a plan established to verify the modeling if a significant risk is indicated for a specific population or environment);

m. a review and illustration of groundwater classifications (the need for institutional controls on ground-water use, considering such controls as adjuncts to remedial action, must be assessed);

n. all physical and chemical waste characteristics that may affect the possible type of treatment (this information must be reported in a chart for each detected compound);

o. the potential risks associated with future releases resulting from onsite residuals; and

p. the background levels for groundwater quality at a sufficient number of horizontal and vertical locations, including unconsolidated overburden and bedrock.

2. Work Plan Requirements

W.R. Grace & Co. shall design investigations that are sufficient to fully address the objectives listed above and others that may arise during the RI/FS. The plan for the subsurface and hydrogeological investigations shall be presented in the FSP. The FSP

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shall also describe the locations, methods, field forms, procedures, and types of analyses to be used in performing the subsurface and hydrogeological investigations. This description shall include specific drilling methods and protocol to be used. The Ground Water Technical Enforcement Guidance Document (OSWER Directive 9950, Sept. 1986) and the Guidance on Remedial Actions for Contaminated Ground Water at Superfund Sites (OSWER Dir. 9283.1-2 Final Review Draft, EPA, August 1988) shall provide the framework of these investigations. The plan shall clearly show the relations between the objectives and the studies to be performed (see Sections 1 and 4). The plan shall provide for GP review of deviations from the Work Plan procedures due to unforeseen field conditions. The plan shall allow additional work contingent on the results of the studies described in the Work Plan for the RI/FS.

3. Reporting Requirements

For the subsurface and hydrogeological investigations. W.R. Grace & Co. shall present the results and describe the actual procedures (especially when the actual procedures differ from those in the work plan) in a section of the Draft RI report. The section shall contain all data, analyses, maps, cross sections, and charts necessary to meet the objectives for which the investigations were performed. Illustrations shall clearly identify the data points, values, and the degree of interpolation or extrapolation necessary to draw conclusions.

C. Surface Water and Sediments

1. Objectives

W.R. Grace & Co. shall determine the nature and extent of contamination from the Site to surface water bodies including but not limited to Sinking Pond. Releases to surface water that will be evaluated include groundwater migration and the discharge of treated groundwater to Sinking Pond. W.R. Grace & Co. shall determine the extent to which contamination from the Site has affected or threatens to affect human health and the environment. Work previously done may be incorporated by reference.

To the extent practical, upgradient samples of water and sediment shall be collected (and analyzed) from several locations in each surface water flow path determined to be receiving discharge of contaminated groundwater or treated groundwater. The collection and analysis of the upgradient samples shall be sufficient to determine background concentrations of analytical parameters. Sampling schedules shall include the monitoring of seasonal changes, including low flow periods, and shall conform to the procedures and requirements of the Project Operations Plan (Section 2).


W.R. Grace & Co. shall prepare a plan for additional surface water and sediment sampling during the scoping of the RI/FS if appropriate. This plan shall be part of the FSP. It shall contain provisions for additional sampling and more general assessments of wetlands, streams, and lakes if this additional work is needed. The plan shall allow for GP review of proposed differences between the actual field work and the specifications for the field work.

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The surface water and sediment sampling data shall be compiled and presented in the draft RI Report and shall include tables, graphs, charts, and other visual aids. These illustrations shall indicate the static levels and seasonal fluctuations of water levels and the impacts of those changes on contaminant concentration and migration.

D. Long-term Monitoring and Sampling

1. Objectives

W.R. Grace & Co. shall monitor the groundwater and potentially surface water and sediment to determine the long-term changes in the nature, extent, quantity, seasonal variability, climatological influence, environmental fate and transport, background levels, and migration pathways for each contaminant at the Site. Long-term-monitoring and sampling for groundwater has commenced in accordance with the EPA/DEP accepted Post Closure Groundwater Monitoring Plan.


W.R. Grace & Co. shall revise the previously submitted plan for periodically sampling and monitoring contaminants in ground water on a long-term basis. The Long-Term Monitoring and Sampling Plan shall be revised as part of the Work Plan for the RI/FS. The plan shall include provisions for needed expansions of the type, quantity, and coverage of the monitoring.

The plan shall also include a thorough discussion of the statistical and mathematical techniques to be used in comparing the results of each sampling round to previous sampling results. Notable differences shall be explained and resolved by repeating sampling and analyses, if necessary. The plan shall be consistent with the procedures and requirements established in the Project Operations Plan (Section 2), the overall objectives (Section 1), and the other components of the Phase 1 RI (Section 4). The plan shall accommodate expansion, including further studies that may be required by the GPs. The plan shall also allow the GPs review before deviating from the original work plan specifications for field work.

The long-term monitoring, for the most part, shall be separate and in addition to the site-specific studies.


Results shall be presented after the sampling and in accordance with the procedures described in the Project Operations Plan (Section 2). Results of each round of sampling shall be statistically and mathematically evaluated as required in the current plan or as may be revised. Deviations and trends shall be illustrated and explained.

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E. Treatability and Pilot Studies

1. Objectives

The objective of the treatability and pilot studies is to obtain the information necessary to evaluate the effectiveness of potential remedial treatment technologies. W.R. Grace & Co. shall conduct laboratory-scale simulations of treatment processes to evaluate the treatability of contaminated ground water and other environmental media. In any treatability and/or pilot studies, W.R. Grace & Co. shall evaluate treatment options, including biological treatments, physical separation, chemical conditioning, and in situ treatments.

The data from additional sampling programs and previously published data on the Site may be sufficient to develop a well-designed pilot program. Before dynamic modeling, bench-scale tests may be performed to establish the "preliminary" treatability of contaminated media. Through the bench-scale tests, W.R. Grace & Co. may initially evaluate the applicability of treatments.

The treatability studies may be conducted anytime during the RI upon approval of the GPs. The GPs may require treatability or pilot studies at any time during the RI/FS.


W.R. Grace & Co. shall prepare a work plan for the treatability and pilot studies and shall include this in the Work Plan for the RI/FS. A Treatability Study Work Plan shall be submitted to the GPs for approval prior to the performance of treatability and pilot studies or upon the request of the GPs. The Treatability Study Work Plan must clearly define the purpose of the study and include a detailed test plan including drawings and a step-bystep procedure, if applicable.


Results of treatability and pilot studies shall be submitted to the GPs in the form of a report describing methods, analyses, and results.

IV. THE DEVELOPMENT AND INITIAL SCREENING OF ALTERNATIVES

A. Development of Alternatives

W.R. Grace & Co. shall develop an appropriate range of waste management options in a manner consistent with the National Contingency Plan (NCP) (40 CFR Part 300), the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (OSWER Directive 9355.3-01), and any format or guidance provided by Region 1 EPA. Alternatives for remediation shall be developed by assembling combinations of technologies (including innovative ones) and the media to which they would be applied, into alternatives that address contamination at the Site or for an identified operable unit.

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1. Objectives

Alternatives shall be developed that:

a. protect human health and the environment by recycling waste or by eliminating, reducing, and/or controlling risks to human health and the environment posed by the groundwater and associated media;

b. consider the long term uncertainties associated with land disposal;

c. consider the goals, objectives, and requirements of the Solid Waste Disposal Act;

d. consider the persistence, toxicity, mobility, and propensity to bioaccumulate of hazardous substances and their constituents;

e. consider the short and long term potential for human exposure;

f. consider the potential threat to human health and the environment if the remedial alternative proposed was to fail; and

g. consider the threat to human health and the environment associated with excavation, transportation, and redisposal or containment of contaminated substances and/or media.

2. Development

In addition, W.R. Grace & Co. shall perform, at a minimum, the following activities:

a. development of remedial action objectives specifying the contaminants and media of concern, potential exposure pathways, and preliminary remediation goals that are based on chemical specific ARARs, risk assessments, and Site characterization data;

b. development of response actions for each media of interest defining engineering controls, treatment, excavation, pumping, or other actions, separately and in combinations;

c. identification of volumes or areas of media to which response actions shall apply;

d. identification and screening of technologies, including innovative ones, that would be applicable to each response action;

e. identification and evaluation of technology process options;

f. assembly of the selected technologies into alternatives representing a range of treatment and containment options; and

g. identification and evaluation of all the handling, treatment, and final disposal of all treatment residuals.

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B. Initial Screening of Alternatives

1. Criteria

In screening the alternatives, W.R. Grace & Co. shall consider, but not be limited to, the short and long term aspects of the following three criteria:

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, and minimizes short-term impacts. It also focuses on how quickly the alternative achieves protection with a minimum of short term impact in comparison to how quickly the protection shall be achieved.

Implementability. This criterion focuses on the technical feasibility and availability of the technologies that each alternative would employ and the administrative feasibility of implementing the alternative.

Cost. The costs of construction and any long-term costs to operate and maintain the alternatives shall be considered.

2. Range of Alternatives

W.R. Grace & Co. shall develop a series of alternatives for the site including, but not limited to, the following:

a. An alternative that throughout the entire soil, source, and/or groundwater plume reduces the contaminant concentrations to meet or attain levels below all MCLs, nonzero MCLGs, ARARs, and a 10-6 excess cancer risk. It shall achieve this objective as rapidly as possible and must be completed in less than 10 years and shall require no long term maintenance.

b. A no action alternative that would rely solely upon natural attenuation to meet cleanup standards. This may be "no further action".

c. For groundwater response actions, W.R. Grace & Co. shall develop a limited number of remedial alternatives that attain site-specific remediation levels within different restoration time periods utilizing one or more different technologies if they offer the potential for comparable or superior performance or implementability; fewer or lesser adverse impacts than others available approached; or lower costs for similar levels of performance than demonstrated treatment technologies.

W.R. Grace & Co. shall give special consideration to innovative technologies. One or more such technologies shall be evaluated beyond the initial screening.

An alternative that involves no need for long-term maintenance and the no action alternative shall be carried through the development and screening and shall be analyzed during the Detailed Analysis of Alternative (Table 1).

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C. Reporting All alternatives shall be presented in the Development and Initial Screening Report (see next section). If an alternative is to be eliminated it must be screened out for clearly stated reasons contained in the NCP (40 CFR Part 300) and other EPA guidances.

V. SCHEDULE AND DELIVERABLES

A. Draft RI Report

A Draft Remedial Investigation Report (Draft RI) shall be prepared by W.R. Grace & Co. and submitted to the GPs for review as a Phase 1 deliverable. The Draft RI shall describe and display in appropriate maps, tables, and figures, any results from pre RI/FS sampling, the Phase 1 Field Investigations and parallel samples taken by EPA or Commonwealth of Massachusetts available to W.R. Grace & Co.. The Draft RI shall include a Site Characterization Report which shall consider, and if appropriately valid, use all available pre-RI/FS, Phase 1, and government field sample results. The Draft RI shall meet the requirements and objectives of the National Contingency Plan, the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (EPA/540/G-89/004, OSWER Directive 9355.3-01, October 1988), and Sections 1, 2, 3, and 4 of the Statement of Work.

The draft RI Report shall include the methods, data gathered and analyses of results. W.R. Grace & Co. shall evaluate how well the studies satisfy the objectives of the RI/FS (Section 1), the Phase 1 RI (Section 4), and the objectives stated in study descriptions (Section 4). The report shall also explain differences between the actual field work and the work specified by Work Plans for the RI/FS. Deficiencies in satisfying the objectives shall be clearly stated. Compilations of data shall be presented in formats that can accommodate the results of additional studies. To the extent possible, W.R. Grace & Co. shall provide data compilations on computer data bases that are compatible with those used by EPA Region I and DEP/CERO.

B. Development and Initial Screening of Alternatives Report

A Development and Initial Screening of Alternatives Report shall be submitted to the GPs (Table 1) for review as a RI deliverable. The report shall contain a chart of all alternatives and the analysis of the basic factors described in Section 4, IV. The report shall justify deleting, refining, or adding alternatives. It shall also identify the data needed to select a remedy and the work plans for studies designed to obtain the data. The report shall contain charts, graphs, and other graphics to display the effectiveness of the alternatives including but not limited to:

1. maps showing the three-dimensional extent of groundwater contamination across the Site;

2. graphs showing the predicted concentration reduction over time for potential ground water remedial alternatives.

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C. Work Plans

1. Detailed Analysis of Alternatives Work Plan

A Detailed Analysis of Alternatives Work Plan, which shall describe the methods by which W.R. Grace & Co. shall evaluate the potential remedial alternatives shall be submitted to EPA for review as a Phase 1 deliverable. This Work Plan shall be consistent with the National Contingency Plan, Section 5.0 of this SOW, and shall consider the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (EPA/540/G-89/004. OSWER Directive 9355.3-01, October 1988).

2. Post-Screening Field Investigation Work Plan

A Post-Screening Field Investigation Work Plan shall also be prepared by W.R. Grace & Co. and submitted to the GPs for review as a deliverable. Alternatives, particularly those involving innovative technologies, may require additional field investigations to obtain data needed for the further evaluation of Site characteristics and the detailed analysis of alternatives. The Post-Screening Field Investigation Work Plan (Phase 2 RI) shall include, but not be limited to:

a. supplemental literature searches to obtain additional data on treatment technologies;

b. bench and pilot scale treatability tests; and

c. the collection of additional field data to assess further the characteristics of the Site.

The Post-Screening Field Investigation Work Plan shall conform to the objectives, procedures, and methods described in Sections 1-4 of the Statement of Work. The investigations shall include the collection of data needed to evaluate the effectiveness of the remedial alternatives, conceptually design remedial actions, select a remedy, and sign a Record of Decision. In the Post-Screening Field Investigation Work Plan, W.R. Grace & Co. shall describe the methods and procedures to be followed to perform field investigations necessary to fill the remaining data gaps. If W.R. Grace & Co. believes that no further field investigations are necessary, they must provide an explanation of how the previous studies fulfilled all of the data objectives and requirements of the National Contingency Plan and the Statement of Work.

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SECTION 5: POST-SCREENING FIELD INVESTIGATION

I. OBJECTIVES

The purpose and objective of this phase is to provide for the information required to fill all relevant data gaps and to provide information necessary to perform the Detailed Analysis of Alternatives and the preparation of the first draft RI/FS. This may include, but not be limited to, bench and pilot studies of potential technologies, literature searches, and field investigations. Field investigations must be performed by W.R. Grace & Co., if information relevant to the selection of a remedial action alternative is not sufficient to perform a Detailed Analysis of Alternatives that shall result in a remedy consistent with the National Contingency Plan. W.R. Grace & Co. must also perform additional field investigations if new areas of concern are identified that require characterization to accurately define the Site boundaries.

II. DETAILED ANALYSIS OF ALTERNATIVES

A. Analysis

The Detailed Analysis of Alternatives consists of an assessment of individual alternatives against each of the nine (9) evaluation criteria and a comparative analysis that focuses upon the relative performance of each alternative against those criteria. The analysis shall be consistent with the National Contingency Plan (NCP) (40 CFR Part 300) and shall consider the Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA (OSWER Directive 9355.3-01). The nine criteria are as follows:

1. Overall protection of human health and the environment 2. Compliance with 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 Acceptance 9. Community Acceptance

Criteria one (1) and two (2) from the above list are considered threshold criteria. This means that an alternative must meet these two (2) criteria or must contain a statutory basis for waiving compliance with specific ARARs in order for it to be eligible for selection. Criteria three (3) through seven (7) on the above list are considered primary balancing criteria. These five (5) criteria are used to further evaluate alternatives that satisfy the threshold criteria. The final two (2) criteria, state acceptance and community acceptance, are modifying criteria that shall be considered by EPA in remedy selections.

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B. Reporting

The Detailed Analysis of Alternatives report, which shall be presented in the FS, shall contain the following:

1. further definition of each alternative with respect to the volumes or areas of contaminated media to be addressed, the technologies to be used, and any performance requirements associated with those technologies;

2. a process scheme for each alternative which describes how each process stream, waste stream, emission residual, or treatment product shall be handled, treated and/or disposed;

3. an assessment and a summary profile of each alternative against the nine (9) evaluation criteria; and

4. a comparative analysis among the alternatives to assess the relative performance of each alternative with respect to each evaluation criterion.

III. DELIVERABLES FROM POST-SCREENING FIELD INVESTIGATIONS

A. Draft RI/FS

W.R. Grace & Co. shall submit a complete Draft Remedial Investigation/Feasibility Study to the GPs for review after completing the Post-Screening Field Investigation. This and any subsequent drafts of the RI/FS shall conform to the NCP (40 CFR Part 300), the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (EPA/540/G-89/004, OSWER Directive 9355.3-01, October 1988), and any additional format, guidance, or examples provided by EPA. The FS section shall include a chart that delineates each criteria listed in Section 5.II. for each alternative. Other graphics shall be included that allow for comparisons of multiple alternatives at various risk, cost, and clean-up levels for sediments, groundwater or surface water as appropriate. These include but are not limited to graphs of the cost of potential remediation alternatives plotted against a range of clean-up levels, and projected concentrations plotted against time for proposed alternatives. W.R. Grace & Co. shall compare the alternatives by using the listed criteria and other appropriate criteria consistent with the National Contingency Plan and all previous Sections of this Statement of Work.

B. Work Plan

Subject to the requirements of the Consent Decree and the DEP Amended Order, if the GPs or W.R. Grace & Co. determine that additional studies are needed, W.R. Grace & Co. shall submit a work plan for approval by the GPs and perform the studies consistent with a GP approved work plan.

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SECTION 6: Public Comment

The final draft Remedial Investigation/Feasibility Study shall be submitted for public comment. After the public comment period, W.R. Grace & Co. shall assist in preparing a responsiveness summary. This assistance shall include, but not be limited to, providing the draft responses to any comments within two weeks of the date the comments are made available to W.R. Grace & Co.. If assistance by W.R. Grace & Co. to numerous technical or extensive comments is needed and an extension is requested, the deadline can be extended beyond the two week deadline by an appropriate time period.

G/projrmd/acton/ou3/so\vtlnal.doc

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ATTACHMENTl; Ecological Risk Assessment Statement of Work

The purpose of this Statement of Work is to establish the tasks, deliverables, and schedule for completion of a Baseline Ecological Risk Assessment of Sinking Pond, other surface water bodies and wetlands in which the natural discharge of contaminated groundwater from the site is present, and waterbodies and wetlands which have received or are receiving discharges from the ARS system or drainage from the site. After review of existing data and establishment of the data base referred to in the RI/FS SOW, W.R. Grace shall conduct a Baseline Ecological Risk Assessment. The objective of this Ecological Risk Assessment is to characterize and, where appropriate, quantify the current and potential environmental risks to the areas described above.

All deliverables under this Work Assignment shall be reviewed by the Government Parties (EPA and the MADEP). This document is part of the Scope of Work for the Operable Unit Three Remedial Investigation/Feasibility Study ("RI/FS") and is subject to all of the general provisions of that document.

Risk Assessment Guidance

W.R. Grace shall use the following as guidance in developing the Ecological Risk Assessment:

Framework for Ecological Risk Assessment (EPA 630/R-92/001, February 1992).

EPA Region I Supplemental Risk Assessment Guidance for the Superfund Program Part 1: Public Health Risk Assessment and Part 2: Ecological Risk Assessment (EPA 901/5/89-001, June, 1989).

Risk Assessment Guidance for Superfund. Volume II: Environmental Evaluation (EPA 540/1-89/001, March 1989).

Guidance for Data Usability in Risk Assessment, Part A (Publication 9285.709A/FS, May 1992).

Ecological Assessment of Hazardous Waste Sites: A Field and Laboratory Reference Document (EPA 600/3-89/013, March 1989).

Draft Guidelines for Ecological Risk Assessment. (EPA/630/R-95/002B).

Proposed Guidelines for Ecological Risk Assessment. Notice. Federal Register Vol. 61 No. 175: 47552-47631. September 9, 1996.

Guidance for Disposal Site Risk Characterization (chapter 9) BWSC/ORS-95-141

Menzie, C. et al. 1996. Special Report of the Massachusetts Weight of Evidence Workgroup: A Weight-of-evidence Approach for Evaluating Ecological Risks. Human and Ecological Risk Assessment; Vol. 2, No. 2, pp. 277-304.

1

Risk Assessment Methodologies

Data Acquisition

The Ecological Risk Assessment shall be based upon information gathered during previous investigations at the site that achieves appropriate and relevant data quality objectives, data available through peer-reviewed literature, and additional field data collected as appropriate.

Phase 1 Screening Ecological Risk Assessment

Problem formulation in the Phase 1 Ecological Risk Assessment Work Plan may identify significant information gaps that need to be addressed. If this is the case then a screening level ecological risk assessment shall be developed to focus additional problem formulation, conceptual model development, and informational gathering.

Ecological Risk Assessment

The Framework for Ecological Risk Assessment produced by EPA's Risk Assessment Forum outlines a basic fundamental approach to performing ecological risk assessments. It consists of three principal components: 1) Problem Formulation; 2) Analysis; and 3) Risk Characterization. The Ecological Risk Assessment shall follow this structure.

Of particular importance in the Risk Characterization phase is utilizing a weight of evidence approach to evaluate the conclusions, strengths, weaknesses, and uncertainties associated with multiple lines of evidence. The attributes defined in the approach A Weight of Evidence Approach for Evaluating Ecological Risks (Menzie et al, 1996) shall be followed to systematically evaluate the information collected.

Tasks

W.R. Grace shall prepare interim and final deliverables outlined under Tasks 1, 2 and 3 as components of the development of the Ecological Risk Assessment.

W. R. Grace shall provide a Phase 1 Ecological Risk Assessment Work Plan and a Phase 1 Screening Ecological Risk Assessment. The Phase I screening Ecological Risk Assessment shall contain recommendations on whether additional risk assessment is required.. If so, these additional tasks shall be described in a Phase 2 Ecological Risk Assessment Work Plan. The results of the Phase 1 Screening Ecological Risk Assessment and any required additional Phase 2 Ecological Risk Assessment activities shall be incorporated in a Draft Ecological Risk Assessment report, which shall be revised based on GP comments and resubmitted.

Task 1: Project Planning

Task 1.1 Review of Site Documents/ Information

W.R. Grace shall review all documents containing site data collected to date to determine which data achieve relevant and appropriate data quality objectives. W.R. Grace shall use validated data whenever possible.

Task 1.2 Data Management and Formatting

W.R. Grace shall review all raw data from studies conducted in the past. W.R. Grace shall then create a database to summarize all data for use in other tasks under this Work Assignment. These data summaries shall be provided to the Government Parties for review.

Task 1.3 Work Plans

W.R. Grace shall submit a Phase 1 Ecological Risk Assessment Work Plan and, if necessary to resolve data gaps, a Phase 2 Ecological Risk Assessment Work Plan. The Work Plan shall include data requirements, including data format, for the completion of the Ecological Risk Assessment. The Phase 1 Ecological Risk Assessment Work Plan shall include a preliminary Problem Formulation statement that describes the components outlined in Task 2.1 (below) and preliminary ecological exposure and effects components (historic data summary, COCs, formulas, RTVs, assumptions, etc.) outlined in Task 2.2 (below). Preliminary information needed to fill data gaps in the conceptual model shall be identified, and provisions made to collect this information in the Phase 1 RI/FS Sampling and Analysis Plan.

Task 2; Ecological Risk Assessment

Task 2.1 Problem Formulation Statement

W. R. Grace shall provide a preliminary Problem Formulation Statement as part of the Phase 1 Ecological Risk Assessment Work Plan. After receipt of GP comments on the Phase 1 Ecological Risk Assessment Work Plan, W.R. Grace shall revise the Problem Formulation Statement. If a Phase 2 Ecological Risk Assessment Work Plan is necessary, the Problem Formulation Statement shall also be revised after receipt of GP comments on the Phase 2 Work Plan. The components of the ecological scope of work and the requirements for the Ecological Risk Assessment are outlined below.

Definition of Stressors: The primary stressor(s) shall be identified from a list of contaminants of concern. The Ecological Risk Assessment shall review all data collected to determine the final list of COCs.

Ecosystem Potentially at Risk: The ecosystem potentially at risk includes Sinking Pond,, other surface water bodies and wetlands in which the natural discharge of contaminated groundwater from the site is present, and waterbodies and wetlands which have received or are receiving discharges from the ARS system or drainage from the site.

Selection of Assessment Endpoints: Assessment endpoints must be defined in the Ecological Risk Assessment. Assessment endpoints are explicit expressions of the actual environmental value that is to be protected. Well-defined assessment endpoints provide clear direction for the risk characterization, promote clear communication of risks, and reduce the uncertainties in the assessment.

Selection of Measurement Endpoints: The definition of measurement endpoints shall be derived in the Ecological Risk Assessment. Measurement endpoints are measurable responses to a stressor that are related to the valued characteristics chosen as the assessment endpoints.

Conceptual Model Development: The conceptual model shall be developed in the Ecological Risk Assessment based upon stressor, ecosystem at risk and assessment and measurement endpoints. The model shall tie together the measurement endpoints with the appropriate assessment endpoints. The weight of evidence attributes shall be used to evaluate the measurement endpoints and their relationship to assessment endpoints.

Each measurement endpoint shall be evaluated using the weight of evidence attributes to estimate the relative strengths, weaknesses, and uncertainties. This shall provide an estimate of how data may be considered during the weighing of the lines of evidence during the risk characterization. Any additional information needed to fill data gaps in the conceptual model shall be identified in the Phase 1 Screening Ecological Risk Assessment. If these data gaps must be resolved (based on GP review), they shall be included in a Phase 2 Ecological Risk Assessment Work Plan provided for collecting this information.

Task 2.2 Analysis Stage

The Analysis Stage focuses on the technical evaluation of the data, characterizing ecological effects and exposure.

The Analysis Stage of the Ecological Risk Assessment shall contain the following information:

Characterization of exposure

Summary of sediment, water and biota data, including tabular or graphical displays; definition of any equations, statistics or other procedures or assumptions for each appropriate measurement endpoint, where needed; and discussion of uncertainties.

Characterization of Ecological effects

Discussion of primary and secondary ecological effects associated with COCs, receptors, and mode of exposure; definition of reference toxicity values (RTVs) defining the stressor/response relationship for COCs for each appropriate measurement endpoint, where needed; and discussion of extrapolations and other assumptions, and uncertainties associated with the ecological effects.

The Analysis Stage is expected to incorporate the full discussion of the analysis component of the Phase 1 Screening Ecological Risk Assessment and the Draft Ecological Risk Assessment, and shall present succinctly the assumptions, RTVs, formulas, etc. that shall be used in generating the analysis section.

Task 2.3 Risk Characterization

The final phase of the Ecological Risk Assessment, risk characterization, evaluates the likelihood of adverse effects occurring as the result of the exposure of the receptors to the stressors, as defined in the assessment and measurement endpoints. There are two primary components of this phase; an estimation of the risks, and a description and interpretation of the risks, using the weight of evidence approach and including a full discussion of uncertainties.

The Phase 1 Screening Ecological Risk Assessment and the Draft Ecological Risk Assessment shall evaluate, for each measurement endpoint, the relevant data according to the approach defined in the conceptual model. The uncertainties specific to each estimate shall be fully outlined.

Risk Description: The risk description section summarizes all of the risk estimates, discusses the evidence supporting the estimates (weight of evidence), and interprets the significance of the evidence, resulting in a finding regarding the baseline ecological risks.

Utilizing all assessment endpoints, the Phase 1 Screening Ecological Risk Assessment and the Draft Ecological Risk Assessment shall include an evaluation of the evidence of risk and the relative significance of the evidence with regard to nature, magnitude, spatial, and temporal characteristics of the response(s), and the uncertainties surrounding the responses. The discussion should culminate in a finding of the baseline ecological risk.

Task 2.4 Submittal of Draft Ecological Risk Assessment Report

W.R. Grace shall prepare and submit a Draft Ecological Risk Assessment

Task 2.5 Final Draft Ecological Risk Assessment

W.R. Grace shall prepare and submit a Final Draft Ecological Risk Assessment revised in response to GP comments .

Task 3: Geographic Information System (GIS)

After evaluating the magnitude and diversity of information collected during the Sinking Pond investigations and other wetland or waterbody investigations, W.R. Grace shall propose appropriate mapping techniques to spatially present the data and the risk assessment results.

References

Menzie, C. et al. 1996. Special Report of the Massachusetts Weight of Evidence Workgroup: A Weight-of-evidence Approach for Evaluating Ecological Risks. Human and Ecological Risk Assessment; Vol. 2, No. 2, pp. 277-304.

DELIVERABLES AND SCHEDULE

Deliverable

Phase 1 ERA Work Plan

Phase 1 Screening ERA

GP Comments

Phase 2 ERA Work Plan (if required)

GP Comments

Draft ERA

GP Comments

Final Draft ERA

g:\projrmd\acton\ou3\necorafinal.doc

Responsibility

WRG

WRG

GP

WRG

GP

WRG

GP

WRG

Schedule

TBD (to be submitted with Phase 1 RI/FS Workplan for OU-3)

TBD (to be submitted with Draft RI for OU-3

TBD

TBD (to be submitted with Phase 2 RI/FS Workplan for OU-3)

TBD

TBD(to be submitted with First Draft RI/FS for OU-3)

TBD

TBD (to be submitted with Final Draft RI/FS for OU-3)

ATTACHMENT 2: BASELINE PUBLIC HEALTH RISK ASSESSMENT STATEMENT OF WORK

Baseline Public Health Risk Assessment Objective

The primary objective is to characterize and quantify, where possible, the current and potential public health risk that would prevail if no further remedial action was taken in Operable Unit Three (OU-3) at the W.R. Grace site in Acton. After evaluation of the field investigation information and site files, W.R. Grace shall prepare a Public Health Risk Assessment (PHRA) and the necessary public health risk assessment documents. Because OU-3 involves the following: groundwater, the natural discharge of contaminated groundwater to surface water bodies, and the discharge of treated groundwater to Sinking Pond, the Baseline Public Health Risk Assessment shall evaluate those exposures associated with current and future use of groundwater, and associated media - affected surface waters, and sediment. This document is part of the Statement of Work for Operable Unit Three Remedial Investigation/Feasibility Study ("RI/FS") and is subject to all the general provisions of that document.

Public Health Risk Assessment Guidance

The Public Health Risk Assessment must be done in accordance with the guidance, procedures, assumptions, methods, and formats contained in:

Human Health Evaluation Manual. Supplemental Guidance: "Standard Default Exposure Factors" OSWER Directive 9285.6-03 (EPA, March 25, 1991).

EPA Region I Supplemental Risk Assessment Guidance for the Superfund Program Part 1: Public Health Risk Assessment and Part 2: Ecological Risk Assessment (EPA 901/5/89-001, June 1989).

Risk Assessment Guidance for Superfund. Volume I: Human Health Evaluation Manual (Part A) Interim Final (EPA 540/1/89, December 1989).

Risk Assessment Guidance for Superfund, Volume II: Environmental Evaluation (EPA 540/1-89/001, March 1989).

Guidance for Data Usability for a Risk Assessment. Part A (Publication 9285.7-09A/FS, May 1992).

Air/Superfund National Technical Guidance Study Series, Volumes I, II, III, and IV (EPA 450/1-89-001, 002,003, 004, July 1989).

Ecological Assessment of Hazardous Waste Sites: A Field and Laboratory Reference Document (EPA 600/3-89/013), March 1989).

Guidance for Exposure Assessment. Federal Register 57:22888-22938.

EPA Region I Supplemental Risk Assessment Guidance for the Supertund Program Part 1: Public Health Risk Assessment

Human Health Evaluation Manual. Supplement Guidance: "Standard Default Exposure Factors" OSWER Directive 9285.6-03 (EPA, March 25, 1991).

USEPA, Draft Exposures Factors Handbook, August, 1996, Office of Research and Development, National Center for Environmental Assessment, Washington, D.C.

USEPA, Region 1, Waste Management Division Risk Updates, December 1992

USEPA, Region 1, Risk Updates, No. 2., August, 1994

USEPA, EPA New England, Risk Updates, No. 3., August, 1995

USEPA, Region 1, Risk Updates, No. 4., November 1996

Some additional Guidance that may be used to prepare and conduct a public health risk assessment are:

1. Carcinogen Risk Assessment (51 FR 33992, September 24, 1986)

2. Mutagenicity Risk Assessment (51 FR 34006, September 24, 1986).

3. The Health Risk Assessment of Chemical Mixtures (51 FR 34014, September 24, 1986).

4. The Health Assessment of Suspect Developmental Toxicants (56 FR 63798, Decembers, 1991).

Before applying site-specific risk assessment approaches not addressed by the above mentioned guidances, W.R. Grace shall present the approaches to the Government Parties and obtain agreement for their use.

Public Health Risk Assessment Methodologies

Components of the Public Health Risk Assessment

The Public Health Risk Assessment must include the following five components at a minimum:

1. Hazard Identification 2. Dose-response Assessment 3. Exposure Assessment 4. Risk Characterization 5. Limitations/Uncertainties

Data Acquisition

The Public Health Risk Assessment shall be based upon information gathered prior to and during the OU-3 RI/FS at the site, as well as data available through a review of the literature. The decision regarding the need for supplemental data collection shall be made after review of the Phase I RI data by the Government Parties. Primary importance shall be placed upon data collected in the field at the site. Data collected from the literature can be used to support or explain field results where appropriate.

Deliverables

The final product shall be the Draft Baseline Public Health Risk Assessment Report. Prior to the submission of the final report, portions of the Baseline Public Health Risk Assessment in the form of interim deliverables (see the table, below) shall be submitted. These interim deliverables shall be reviewed and approved by the Government Parties prior to W.R. Grace proceeding with the next interim deliverable. Once all interim deliverables are approved, a Draft Baseline Public Health Risk Assessment Report shall be submitted. This shall include the interim deliverables as well as the additional information required for the report. Following review and feedback from the Government Parties on the Draft Baseline Public Health Risk Assessment Report, a revised Draft Baseline Public Health Risk Assessment Report may be required, incorporating the Government Parties' comments and any additional data that may have bearing on the risk assessment, acquired after the completion of the draft report.

The content of the interim deliverables are outlined in the following table.

Interim Deliverable Items Scope of Deliverable Deliverable #

1. Standard Table 1 - Selection One Table for each Risk Assessment of Exposure Pathways

Interim Deliverable #

Deliverable Items

1. (cont'd) Data Usability Worksheet

Supporting Information on Background Values

2. Standard Table 2 Occurrence, Distribution, and Selection of COPCs

Supporting Information on EPCs

Standard Table 3 - Medium-Specific Exposure PointConcentration (EPC) Summary

Supporting Information onModeled Intake Methodologyand Parameters

Supporting Information on Chemical-Specific Parameters

Standard Table 4 - Values Used for Daily Intake Calculations

Supporting Information on Toxicity Data for Special Case Chemicals

Standard Table 5 - Non-Cancer Toxicity Data

Standard Table 6 - Cancer Toxicity Data

Scope of Deliverable

One Worksheet for each Medium

Information for all Chemicals listed in Table 2

One Table for each unique combination of Scenario Time frame, Medium, Exposure Medium and Exposure Point

Information for all EPCs presented in Table 3

One Table for each unique combination of Scenario Time frame, Medium, Exposure

Medium and Exposure Point

Information for all Modeled Intake calculations that are not presented on

Table 4

Information for all Chemical-Specific Parameters used

One Table for each unique combination of Scenario Time frame, Medium, Exposure Medium, Exposure Point, Receptor Population and Receptor Age

Information for each Special Case Chemical

Three Tables - 5.1 for Oral/Dermal, 5.2 for Inhalation, and 5.3 for Special Case Chemicals



Deliverable Items

2. (cont'd) Supporting Information on Special Chemical Risk and Hazard Calculations

3. Standard Table 7 - Calculationof Non-Cancer Risks

Standard Table 8 - Calculationof Cancer Risks

Standard Table 9 - Summary of Receptor Risks and Hazards for COPCs

Standard Table 10 - Risk Assessment Summary

Lead Worksheets (if applicable)

Radionuclide Worksheets (if applicable)

Assessment of Confidence and Uncertainty

Summary of Probabilistic Analysis



Separate Table for each unique combination of Scenario Time frame,

Medium, Exposure Medium, Exposure Point, Receptor Population and Receptor Age, for RME and for CT



Separate Table for each unique combination of Scenario Time frame, Receptor Population and Receptor Age, for RME and for CT


Separate Worksheets for Screening Analysis, and Child and Adult Exposures for each Medium


One Assessment for each Risk Assessment

One Summary for each Risk Assessment

Draft Baseline Public Health Risk Assessment

The draft Baseline Public Health Risk Assessment document shall be submitted after the completion and acceptance of the interim deliverables described above. The Public Health Risk Assessment shall include the following five sections:

1. Hazard Identification

The objective of this component is to present an orderly compilation of the available data for groundwater and associated media that represent complete exposure pathways at the site, to identify data sets suitable for use in a quantitative risk evaluation, and if necessary, to identify contaminants of concern upon which the quantitative assessment of risk shall be based.

2. Dose-Response Evaluation

The objective of this component is to identify the nature and probability of adverse health effects which could be expected to result from exposure to the contaminants of concern. Carcinogenic and noncarcinogenic effects are characterized independently. The Dose-Response evaluation for possible carcinogenic effects is described by the cancer slope factor while for noncarcinogenic effects, the reference dose (Rfd) for other suitable health based criteria should be used. GP verified Dose-Response criteria obtained from IRIS should be preferentially utilized.

W.R. Grace shall provide a Dose-Response evaluation consistent with the EPA Region I Supplemental Risk Assessment Guidance for the Superfund Program Part 1: Public Health Risk Assessment Chapter 3.

3. Exposure Assessment

The purpose of the exposure assessment is to estimate a range of possible exposures which may result from actual or threatened releases of hazardous substances from the site. The average and reasonable maximum exposure levels which are to be characterized, are defined by the manner in which the contaminant concentration (central tendency or maximum) is coupled with conservative exposure parameters developed for each exposure scenario in the interim deliverables. The format of the exposure point concentrations and exposure dose levels shall be presented in narrative form and tables.

4. Risk Characterization

Risk characterization integrates the information developed during the toxicity assessment (hazard identification and dose response evaluation) and the exposure assessment to quantitate the risks from the site for each exposure pathway. Presentation of the risk characterization shall be in the form of tables which separately summarize the noncarcinogenic and carcinogenic health risk.

5. Uncertainties and Limitations

This section shall address the uncertainties and limitations of the analysis. It shall clearly address the major limitations, sources of uncertainty, and if possible, provide an indication as to whether they resulted in an over- or under-estimation of the risk.

The format of this report shall conform to the chapters and sections as follows:

I. Draft Public Health Risk Assessment

1.0 Introduction/Hazard Identification

1.1. Site description and history 1.1.1. Present and future use 1.1.2. Human receptors (including type, location and numbers.)

1.2. Nature and extent of groundwater contamination, surface water and sediment affected by the natural discharge of contaminated groundwater or discharge of treated groundwater at the site.

1.3. Selection of contaminants of concern 1.3.1. Health Based ARARs (e.g. MCL/MCLG)

1.4 Fate and Transport

2.0 Exposure Assessment

2.1. Groundwater, Surface water, Sediment Exposure pathways 2.2 Groundwater, Surface water, Sediment Exposure Scenarios

2.2.1 Exposure point concentrations (ug/L, mg/kg, ug/m3) 2.2.2. Exposure dose levels (mg/kg/day)

3.0 Dose Response Evaluation

3.1 Dose response criteria for carcinogenic effects 3.2 Dose response criteria for noncarcinogenic effects

4.0 Risk Characterization

4.1 Narrative and tables summarizing the carcinogenic and noncarcinogenic risks of exposure pathway for the present and potential future exposure scenarios.

5.0 Uncertainty/Limitations

6.0 References

7.0 Appendices

7.1 Documentation/data 7.2 Toxicity profiles for contaminants of concern

Once the draft Public Health Risk Assessment document has been reviewed by the Government Parties, a revised draft Public Health Assessment document may be warranted. The revised draft document shall follow the same format as the draft report and shall address and incorporate any comments provided by the GPs. A Final Draft Baseline Public Health Risk Assessment shall be submitted.

SCHEDULE

Deliverable

Interim Deliverables 1& 2

Revised Interim Deliverables 1& 2

Interim Deliverable 3

Draft Baseline Public Health Risk Assessment(Interim Deliverable 4)

Final Draft Baseline Public Health RiskAssessment(Interim Deliverable 5)

g:\projrmd\acton\ou3\hutnanhrafinal.doc

Due Date

TBD (to be submitted with the Workplan for OU-3 RI/FS)

TBD (to be submitted after Phase 2 RI/FS field work)

TBD (to be submitted after approval of Revised Interim Deliverables 1 & 2)

TBD (to be submitted with the First Draft RI/FS for OU-3)

TBD (to be submitted with the Final Draft RI/FS for OU-3

ATTACHMENT 2: BASELINE PUBLIC HEALTH RISK ASSESSMENT STATEMENT OF WORK

Baseline Public Health Risk Assessment Objective

The primary objective is to characterize and quantify, where possible, the current and potential public health risk that would prevail if no further remedial action was taken in Operable Unit Three (OU-3) at the W.R. Grace site in Acton. After evaluation of the field investigation information and site files, W.R. Grace shall prepare a Public Health Risk Assessment (PHRA) and the necessary public health risk assessment documents. Because OU-3 involves the following: groundwater, the natural discharge of contaminated groundwater to surface water bodies, and the discharge of treated groundwater to Sinking Pond, the Baseline Public Health Risk Assessment shall evaluate those exposures associated with current and future use of groundwater, and associated media - affected surface waters, and sediment. This document is part of the Statement of Work for Operable Unit Three Remedial Investigation/Feasibility Study ("RI/FS") and is subject to all the general provisions of that document.

Public Health Risk Assessment Guidance

The Public Health Risk Assessment must be done in accordance with the guidance, procedures, assumptions, methods, and formats contained in:

Human Health Evaluation Manual. Supplemental Guidance: "Standard Default Exposure Factors" OSWER Directive 9285.6-03 (EPA, March 25, 1991).

EPA Region I Supplemental Risk Assessment Guidance for the Superfund Program Part 1: Public Health Risk Assessment and Part 2: Ecological Risk Assessment (EPA 901/5/89-001, June 1989).

Risk Assessment Guidance for Superfund, Volume I: Human Health Evaluation Manual (Part A) Interim Final (EPA 540/1/89, December 1989).

Risk Assessment Guidance for Superfund. Volume II: Environmental Evaluation (EPA 540/1-89/001, March 1989).

Guidance for Data Usability for a Risk Assessment. Part A (Publication 9285.7-09A/FS, May 1992).

Air/Superfund National Technical Guidance Study Series, Volumes I, II, III, and IV (EPA 450/1-89-001, 002,003, 004, July 1989).

Ecological Assessment of Hazardous Waste Sites: A Field and Laboratory Reference Document (EPA 600/3-89/013), March 1989).

Guidance for Exposure Assessment. Federal Register 57:22888-22938.

EPA Region I Supplemental Risk Assessment Guidance for the Superfund Program Part 1: Public Health Risk Assessment

Human Health Evaluation Manual. Supplement Guidance: "Standard Default Exposure Factors" OSWER Directive 9285.6-03 (EPA, March 25,1991).

USEPA, Draft Exposures Factors Handbook, August, 1996, Office of Research and Development, National Center for Environmental Assessment, Washington, D.C.

USEPA, Region 1, Waste Management Division Risk Updates, December 1992

USEPA, Region 1, Risk Updates, No. 2., August, 1994

USEPA, EPA New England, Risk Updates, No. 3., August, 1995

USEPA, Region 1, Risk Updates, No. 4., November 1996

Some additional Guidance that may be used to prepare and conduct a public health risk assessment are:

1. Carcinogen Risk Assessment (51 FR 33992, September 24, 1986)

2. Mutagenicity Risk Assessment (51 FR 34006, September 24, 1986).

3. The Health Risk Assessment of Chemical Mixtures (51 FR 34014, September 24, 1986).

4. The Health Assessment of Suspect Developmental Toxicants (56 FR 63798, Decembers, 1991).

Before applying site-specific risk assessment approaches not addressed by the above mentioned guidances, W.R. Grace shall present the approaches to the Government Parties and obtain agreement for their use.

Public Health Risk Assessment Methodologies

Components of the Public Health Risk Assessment

The Public Health Risk Assessment must include the following five components at a minimum:

1. Hazard Identification 2. Dose-response Assessment 3. Exposure Assessment 4. Risk Characterization 5. Limitations/Uncertainties

Data Acquisition

The Public Health Risk Assessment shall be based upon information gathered prior to and during the OU-3 RI/FS at the site, as well as data available through a review of the literature. The decision regarding the need for supplemental data collection shall be made after review of the Phase I RI data by the Government Parties. Primary importance shall be placed upon data collected in the field at the site. Data collected from the literature can be used to support or explain field results where appropriate.

Deliverables

The final product shall be the Draft Baseline Public Health Risk Assessment Report. Prior to the submission of the final report, portions of the Baseline Public Health Risk Assessment in the form of interim deliverables (see the table, below) shall be submitted. These interim deliverables shall be reviewed and approved by the Government Parties prior to W.R. Grace proceeding with the next interim deliverable. Once all interim deliverables are approved, a Draft Baseline Public Health Risk Assessment Report shall be submitted. This shall include the interim deliverables as well as the additional information required for the report. Following review and feedback from the Government Parties on the Draft Baseline Public Health Risk Assessment Report, a revised Draft Baseline Public Health Risk Assessment Report may be required, incorporating the Government Parties' comments and any additional data that may have bearing on the risk assessment, acquired after the completion of the draft report.

The content of the interim deliverables are outlined in the following table.

InterimDeliverable #

Deliverable Items Scope of Deliverable

1. Standard Table 1 - Selectionof Exposure Pathways

One Table for each Risk Assessment


Deliverable Items

1. (cont'd) Data Usability Worksheet

Supporting Information on Background Values

2. Standard Table 2 Occurrence, Distribution, and Selection of COPCs

Supporting Information on EPCs

Standard Table 3 - Medium-Specific Exposure PointConcentration (EPC) Summary

Supporting Information on Modeled Intake Methodology and Parameters

Supporting Information on Chemical-Specific Parameters

Standard Table 4 - Values Used for Daily Intake Calculations

Supporting Information on Toxicity Data for Special Case Chemicals

Standard Table 5 - Non-Cancer Toxicity Data

Standard Table 6 - Cancer Toxicity Data



Information for all Chemicals listed in Table 2

One Table for each unique combination of Scenario Time frame, Medium, Exposure Medium and Exposure Point

Information for all EPCs presented in Table 3

One Table for each unique combination of Scenario Time frame, Medium, Exposure

Medium and Exposure Point

Information for all Modeled Intake calculations that are not presented on Table 4

Information for all Chemical-Specific Parameters used

One Table for each unique combination of Scenario Time frame, Medium, Exposure Medium, Exposure Point, Receptor Population and Receptor Age





2. (cont'd)

3.

Deliverable Items

Supporting Information on Special Chemical Risk and Hazard Calculations

Standard Table 7 - Calculationof Non-Cancer Risks

Standard Table 8 - Calculationof Cancer Risks

Standard Table 9 - Summary of Receptor Risks and Hazards for COPCs

Standard Table 10 - Risk Assessment Summary

Lead Worksheets (if applicable)

Radionuclide Worksheets (if applicable)

Assessment of Confidence and Uncertainty

Summary of Probabilistic Analysis









Separate Worksheets for Screening Analysis, and Child and Adult Exposures for each Medium


One Assessment for each Risk Assessment

One Summary for each Risk Assessment

Draft Baseline Public Health Risk Assessment

The draft Baseline Public Health Risk Assessment document shall be submitted after the completion and acceptance of the interim deliverables described above. The Public Health Risk Assessment shall include the following five sections:

1. Hazard Identification

The objective of this component is to present an orderly compilation of the available data for groundwater and associated media that represent complete exposure pathways at the site, to identify data sets suitable for use in a quantitative risk evaluation, and if necessary, to identify contaminants of concern upon which the quantitative assessment of risk shall be based.

2. Dose-Response Evaluation

The objective of this component is to identify the nature and probability of adverse health effects which could be expected to result from exposure to the contaminants of concern. Carcinogenic and noncarcinogenic effects are characterized independently. The Dose-Response evaluation for possible carcinogenic effects is described by the cancer slope factor while for noncarcinogenic effects, the reference dose (Rfd) for other suitable health based criteria should be used. GP verified Dose-Response criteria obtained from IRIS should be preferentially utilized.

W.R. Grace shall provide a Dose-Response evaluation consistent with the EPA Region I Supplemental Risk Assessment Guidance for the Superfund Program Part 1: Public Health Risk Assessment Chapter 3.

3. Exposure Assessment

The purpose of the exposure assessment is to estimate a range of possible exposures which may result from actual or threatened releases of hazardous substances from the site. The average and reasonable maximum exposure levels which are to be characterized, are defined by the manner in which the contaminant concentration (central tendency or maximum) is coupled with conservative exposure parameters developed for each exposure scenario in the interim deliverables. The format of the exposure point concentrations and exposure dose levels shall be presented in narrative form and tables.

4. Risk Characterization

Risk characterization integrates the information developed during the toxicity assessment (hazard identification and dose response evaluation) and the exposure assessment to quantitate the risks from the site for each exposure pathway. Presentation of the risk characterization shall be in the form of tables which separately summarize the noncarcinogenic and carcinogenic health risk.

5. Uncertainties and Limitations

This section shall address the uncertainties and limitations of the analysis. It shall clearly address the major limitations, sources of uncertainty, and if possible, provide an indication as to whether they resulted in an over- or under-estimation of the risk.

The format of this report shall conform to the chapters and sections as follows:

I. Draft Public Health Risk Assessment

1.0 Introduction/Hazard Identification

1.1. Site description and history 1.1.1. Present and future use 1.1.2. Human receptors (including type, location and numbers.)

1.2. Nature and extent of groundwater contamination, surface water and sediment affected by the natural discharge of contaminated groundwater or discharge of treated groundwater at the site.

1.3. Selection of contaminants of concern 1.3.1. Health Based ARARs (e.g. MCL/MCLG)

1.4 Fate and Transport

2.0 Exposure Assessment

2.1. Groundwater, Surface water, Sediment Exposure pathways 2.2 Groundwater, Surface water, Sediment Exposure Scenarios

2.2.1 Exposure point concentrations (ug/L, mg/kg, ug/m3) 2.2.2. Exposure dose levels (mg/kg/day)

3.0 Dose Response Evaluation

3.1 Dose response criteria for carcinogenic effects 3.2 Dose response criteria for noncarcinogenic effects

4.0 Risk Characterization

4.1 Narrative and tables summarizing the carcinogenic and noncarcinogenic risks of exposure pathway for the present and potential future exposure scenarios.

5.0 Uncertainty/Limitations

6.0 References

7.0 Appendices

7.1 Documentation/data 7.2 Toxicity profiles for contaminants of concern

Once the draft Public Health Risk Assessment document has been reviewed by the Government Parties, a revised draft Public Health Assessment document may be warranted. The revised draft document shall follow the same format as the draft report and shall address and incorporate any comments provided by the GPs. A Final Draft Baseline Public Health Risk Assessment shall be submitted.

SCHEDULE

Deliverable

Interim Deliverables 1& 2

Revised Interim Deliverables 1& 2

Interim Deliverable 3

Draft Baseline Public Health Risk Assessment(Interim Deliverable 4)

Final Draft Baseline Public Health RiskAssessment(Interim Deliverable 5)

g:\projrmd\acton\ou3\humanhrafinal.doc

Due Date

TBD (to be submitted with the Workplan for OU-3 RI/FS)

TBD (to be submitted after Phase 2 RI/FS field work)

TBD (to be submitted after approval of Revised Interim Deliverables 1 & 2)

TBD (to be submitted with the First Draft RI/FS for OU-3)

TBD (to be submitted with the Final Draft RI/FS for OU-3

M Mitch Obradovic

Assistant Director

Remediation Management Dept.

W R Grace & Co GRACE 6401 Poplar Avenue, Suite 301

Tel (901)820-2065 Fax (901)820-2061

ATTACHMENT 3

March 25, 1998

Mr. David Lederer Mr. Edmond Benoit, Deputy Regional Director Waste Management Division Bureau of Waste Site Cleanup U. S. Environmental Protection Agency Massachusetts Department of Region I Environmental Protection 90 Canal Street 627 Main Street Boston, Massachusetts 02114 Worcester, Massachusetts 01608

Subject: W. R. Grace & Co. - Conn. Acton Site Operable Unit Three

Gentlemen:

W. R. Grace & Co. - Conn. (Grace) submits herewith and agrees to execute the Operable Unit Three Remedial Investigation/Feasibility Study (RI/FS) Statement of Work (SOW) relating to the Grace Site in Acton, Massachusetts (the Site) pursuant to the schedule set forth in the SOW, on the understanding that Grace and the Government Parties have mutually agreed to reserve their respective positions on the question of the governing statutory or other legal authority.

In particular, Grace understands that the Government Parties take the position that the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (CERCLA), and the equivalent Massachusetts statute apply, which Grace disputes. Grace understands that the Government Parties dispute Grace's position that its obligations are governed solely by the 1980 Consent Decree and the Amended Massachusetts Department of Environmental Protection (DEP) Order. Grace further understands that the Government Parties will not contend that Grace's agreement to the OU-3 RI/FS SOW in any way operates as a waiver of Grace's position or an agreement on Grace's part to the Government Parties position.

Accordingly, and in reliance on the aforesaid mutual agreement and understandings, Grace does hereby reserve its right to contend that its obligations at the Site are governed solely by the 1980 Consent Decree and the Amended DEP Order, and by agreeing to the SOW, Grace does not waive its position nor adopt or accept the Government Parties' position. For its part, Grace will not contend that the Government Parties' agreement to the SOW in any way operates as a waiver of the Government Parties' position or an agreement on their part to Grace's position.

Messrs. Ledererand Benoit 2 March 25, 1998

By submitting the SOW for approval, Grace does not waive its position that any request for a revised report or plan is subject to the dispute resolution provisions of the 1980 Consent Decree. Grace acknowledges that the Government Parties reserve the right to take the position that CERCLA and/or M.G. L. c. 21 E and associated implementing regulations govern disputes among the parties.

As was discussed at the March 28, 1997 meeting, it is Grace's intention to conduct the work called for by the SOW in accordance with the technical procedures and methodologies set out in the National Contingency Plan and the Massachusetts Contingency Plan, to the extent that those technical procedures and methodologies are not inconsistent with Grace's rights under the 1980 Consent Decree and the Amended DEP Order.

Grace's submission of the SOW is expressly conditioned upon receipt of written acknowledgment by the Government Parties of Grace's reservations set forth herein via a Government Party approval letter, substantially in accordance with the draft Government Party approval letter attached to the SOW as Attachment 4.

Very truly yours,

C

M. Mitch Obradovic Assistant Director

jaj

cc: William J. Cheeseman, Esq., Foley, Hoag & Eliot Andy Cohen, DEP Boston Jay Neparstek/DEP Boston J. Demming, Acton Water District Bob Eisengrein, ACES Jack Guswa, GeoTrans Doug Halley, Town of Acton Don Hanson, MADEP Stephen Anderson, Anderson and Kreiger Maryellen Johns, W. R. Grace & Co. Gretchen Muench, Esq.. U.S. EPA Chuck Myette, EMCON Jim Okun, OT&O Bill Pencola, Foster Wheeler Mark Stoler, W. R. Grace & Co. (w/o attachment) R. Sugatt, Normandeau Associates J. Swallow/Pine & Swallow Associates W. Swanson, Camp Dresser & McKee File M-11.8

H:\SHAREDVJJAMES\WORD\MMO\ACTONOU3.DOC

03/10/98 TUE 14:34 FAX FOLEY HOAG & ELIOT LLP 000;

ATTACHMENT4

DRAFT Mitchell Obradovic Remediation Management Department W. R. Grace & Co. - Conn. 6401 Poplar Avenue, Suite 301 Memphis, TN 38119-4840

Re: W.R. Grace Superfund Site, Acton, MA Conditional Approval of Remedial Investigation/Feasibility Study statement of Work Pursuant to Paragraph XII(A) u£ uhe EPA Consent Decree and Paragraph 7 of the DEP Amended Order

Dear Mr. Obradovic:

The U. S. Environmental Protection Agency ("EPA") and the Massachusetts Department of Environmental Protection ("DEP") (collectively the "Government Parties") acknowledge receipt by letter of March , 1998 from W. R. Grace & Co. - Conn. ("Grace") of a Statement of Work for a Remedial Investigation/Feasibility Study ("SOW"). Grace submitted this SOW pursuant to Section XII(A) of the Consent Decree between the United States of America and Grace (Civil Action No. 80-748-C (D. Mass.)) ("Consent Decree") and Paragraph 7 of the Amended order issued by DEP (formerly known as the Department of Environmental Quality Engineering) to W. R. Grace & Co. on April 15, 1961 ("Amended Order").

In the March , 1998 letter, Grace agreed to conduct a Remedial Investigation/Feasibility Study for Operable Unit 3 of the w. R. Grace Superfund site in Acton, Massachusetts ("Site") in accordance with uhe SOW, including the schedule contained in the SOW, attached to its letter. Subject to the conditions and reservations set forth below, the Government Parties hereby approve the SOW.

It is EPA's position that the cleanup of the Site is governed by Che Comprehensive Environmental Response, Compensation and Liability Act, 42 U.S.c, Section 9601 et. asg. As you know, the Site was added to the National Priorities List ("NPL") on September 8, 1983, pursuant to Section 105 of CERCLtA. As a result, it is EPA's position that the substantive and procedural requirements of CBRCLA and the National Contingency Plan ("NCP") must be followed at this Site.

in addition, the Site is currently classified ae a Ti«x- 1A site in Che Massachusetts Sites DuLdbase. Ae a result, it ie DEP's position that thie Site is also subject to M.O.L. C.21E, Section 3A and the Massachusetts Contingency Plan

03/10/98 TUE 11:32 [TI/RI NO 7S99]

03/10/98 TUE 14:35 FAX FOLEY HOAG & ELIOT LLP

(MMCP"), in conjunction with CBRCLA and the NCP.

As the Government Parties have consistently maintained, the cleanup of this Site must be c.onducted in accordance with these federal and state laws. The Government Parties continue to aesert that these authorities specifically apply to the conduct of any and all response actions at the site. In its letter of March / 1998, Grace stated its intention to undertake and perform the SOW in conformance with the technical procedures and methodologies of the NCP and the MCP. The conditional approval contained herein io granted with the understanding that any plan, program, report or proposed action that is submitted by Grace for approval by the Government Parties shall be in compliance with all requirements embodied in applicable federal and state laws, including those requirements imposed by the NCP and the MCP.

The Site cleanup is also governed by the agreements of Grace contained in the Consent Decree, by the terms of the Amended Order, and by any plan, program, report or proposed actions approved by the Government Parties under the Consent Decree and the Amended Order. Grace's obligations embodied in the Consent Decree and the Amended Order are to conduct work as approved by the Government Parties. The Government Parties will not approve any work or accept any action governed by the Consent Decree or the Amended Order which is not consistent with CERCLA, M.G.L. C.21E, the NCP and the MCP.

Grace should also understand that notwithstanding the approval transmitted by this letter, the Government Parties reserve their rights under CERCLA, M.G.L. C.21E, and all other legally applicable federal and state laws and regulations to institute proceedings in the underlying judicial and administrative actions or in a new action, or to issue Administrative Orders, seeking to compel Grace to perform additional response actions at the Site and/or to reimburse the Government Parties for response action coats. Further, by approving the SOW, the Government Parties neither waive their position nor adopt or accept Grace's position. As set forth in Grace's March 1998 letter, the Government Parties also understand that Grace will not contend that the Government Parties approval of this SOW in any way operates as a waiver of the Government Parties' position or an agreement by the Government Parties' to the Grace position regarding applicable law.

The Government Parties, on our part, understand that oraoe disputes the applicability of CERCLA, M.G.L. c.21E, the NCP and the MCP to the SOW. In addition, the Government Parties understand that Grace, by agreeing to conduct the work embodied in the SOW does not waive its position nor adopt or accept the Government Parties' position regarding applicable law, Moreover, the Government Parties will not contend that this agreement by Grace to conduct the SOW in any way

03/10/98 TUE 11:32 ITX/RX NO 7599]

®005 FOLEY HOAG & ELIOT LLP03/10/98 TUB 14:35 FAX

operates as a waiver of Grace's position or an agreement by Grace to the Government Parties' position.

Finally, the Government Parties acknowledge that Grace'e submission of the SOW fior approval is not a waiver of Grace's position that any request for a revised report or plan is subject to the dispute resolution provisions of the I960 Consent Decree. The Government Parties reserve the right to take the position that CERCIA and/or M.G.L. c.2iE and associated implementing regulations govern disputes among the parties.

We trust that this letter fully sets forth all conditions and reservations of the Government Parties' approval of the SOW. Should you have any questions about the foregoing/ please contact Gretchen Muench at (617)565-4904 or Andy Cohen at (617)292-5652.

Sincerely,

Harley F. Laing Director Office of Remediation and Restoration Environmental Protection Agency

Bdmond G, Benoit Deputy Director Bureau of Waste Site Cleanup Massachusetts Department of Environmental Protection

Dave Lederer, EPA Don Hanson, MADEP Doug Halley, Town of Acton Andy Cohen/ DEP Boston Bob Biaengrein, ACES Jim okun, OT&O Chuck Myette, EMCON Cynthia Heslen, Anderson and Xreiger Bill Cheeseman, Foley, Hoag & Eliot Bill Pencola, Poster Wheeler Jack Guswa, Geotrans R. Sugatt, Normandeau Associates

03/10/98 TUE 11:32 ITI/RI NO 7599]

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