ARCSRemedial Planning Activitiesat Selected UncontrolledHazardous Substance DisposalSites in Region I

Environmental Protection AgencyRegion I

ARCS Work Assignment No. 26-1 BBS

Risk AssessmentBurgess Brothers Superfund SiteWoodford and Bennington, Vermont

Work Plan

June 1994

TRCCompanies, Inc.

TAMS Consultants, Inc.PEI Associates, Inc.Jordan Communications,

MSM1/S

WORK PLAN RISK ASSESSMENT

BURGESS BROTHERS SUPERFUND SITE WOODFORD AND BENNINGTON, VERMONT

Prepared for

U.S. ENVIRONMENTAL PROTECTION AGENCY Region I

90 Canal Street Boston, Massachusetts 02203

Work Assignment No.: 26-1BB5

EPA Region: I

Contract No.: 68-W9-0033

TRCC Document No.: L94-437

TRCC Project No.: 1-636-027-0-1BB5-1

TRCC Project Manager: Susan Stoloff

Telephone No.: (508) 970-5757, ext. 5271

EPA Remedial Project Manager: Ron Jennings

Telephone No.: (617) 573-5794

Date Prepared: June 2, 1994

TRC COMPANIES, INC. Boott Mills South

Foot of John Street Lowell, Massachusetts 01852

(508) 970-5600

TABLE OF CONTENTS

Section Page

1.0 INTRODUCTION 1

2.0 PROJECT APPROACH 1 2.1 Task 1 - Project Planning and Management 1 2.2 Task 2 - File Review 2 2.3 Task 3 - Meetings with EPA and PRP Contractor 3 2.4 Task 4 - RI Work Plan Review 3 2.5 Task 5 - Development of Baseline Risk Assessment (BRA) 3 2.6 Task 6 - Public Meeting Support 14

3.0 PERSONNEL 14

4.0 SCHEDULE 16 4.1 Period of Performance 17

5.0 DOCUMENT PRODUCTION 17

6.0 SUBCONTRACTING PLAN 17

7.0 EXCEPTIONS/ANTICIPATED PROBLEMS 20

8.0 QUALITY ASSURANCE 21

FIGURES

Number Page

1.0 Program Management Structure 15

L94-437.txt 11

1.0 INTRODUCTION

The U.S. Environmental Protection Agency (EPA), under Contract No. 68-W9-0033, has

requested that TRC Companies, Inc. (TRCC) prepare a baseline risk assessment based on the

results of the Remedial Investigation/Feasibility Study (RI/FS) being conducted at the Burgess

Brothers Superfund site, Woodford and Bennington Vermont. TRCC will conduct the risk

assessment; prepare draft, draft final, and final risk assessment reports as well as a Pathway

Analysis Report; attend four half-day and one full-day meetings in Boston related to the

preparation of the risk assessment; and attend and provide technical support for two public

meetings in Bennington, Vermont.

The assessment will be conducted to evaluate actual and potential impacts to human health

and the environment posed by chemical contaminants associated with the $ite under the "no­

action" remedial option. Results of the risk assessment will assist in determining whether

further remediation at the site is necessary.

2.0 PROJECT APPROACH

TRCC participated in a kick-off meeting with EPA on May 12, 1994 to discuss the scope of

work and approach for this Work Assignment. The outcome of this meeting was summarized

in the TRCC Meeting Summary Memorandum dated May 19, 1994. Activities for this

assignment are expected to include six tasks which are described below.

2.1 Task 1 - Project Planning and Management

The activities under this task pertain to project management work. This work will include the

following:

• participating in the kick-off meeting,

• preparing the Meeting Summary Memorandum,

L94-437.txt 1

• developing and revising (if necessary) the Work Plan and Cost Estimate,

• tracking costs and schedule,

• staffing for risk analysis,

• reviewing available site documents as needed for developing the Work Plan and Cost Estimate,

• maintaining contact with the Work Assignment Manager,

• preparing monthly reports,

• completing project closeout, and

• project management.

Activities already completed under Task 1 include participation in the kick-off meeting,

preparation of the Meeting Summary Memorandum, and preparation of this Work Plan and

Cost Estimate.

This Work Plan and Cost Estimate have been developed based on information provided in the

Statement of Work, discussions during the scoping meeting and subsequent phone

conversations with the Remedial Project Manager, and TRCC's preliminary review of the

Phase lA-Initial Site Characterization Report, dated January 1994.

In accordance with the ARCS contract reporting requirements, TRCC will submit monthly

reports describing the project status, anticipated schedule, anticipated technical labor hours

(TLH) utilization for the following three months, and any current or anticipated problems.

2.2 Task 2 - File Review

TRCC will review the following documents to be provided by the EPA, to become familiar

with background information for the site:

• Preliminary Assessment/Site Investigation

L94-437.txt 2

• Historical Photo Analysis • Limited Field Investigation

Phase 1A RI Report

2.3 Task 3 - Meetings with EPA and PRP Contractor

TRCC will meet with the EPA to discuss the development of the Baseline Risk Assessment

(BRA) outlined in Task 5 of this Scope of Work. TRCC will periodically meet with EPA

and the PRP's contractor performing the RI/FS during this Work Assignment on an as needed

basis. The cost estimate for this task is based on the assumption that TRCC will prepare for

and attend four half-day and one full-day meetings in Boston under this task.

2.4 Task 4 - RI Work Plan Review

TRCC will review the Phase IB RI Work Plan submitted by the PRP contractor to determine

if data quality objectives will be met for the Baseline Risk Assessment. TRCC will provide

written comments to EPA in memorandum format.

2.5 Task 5 - Development of Baseline Risk Assessment (BRA)

Most of the effort under this assignment will be devoted to conducting the risk assessment.

The assessment will evaluate the actual and potential risks to human health and ecological

receptors posed by chemical contaminants released from the Burgess Brothers site under "no­

action" conditions. As recommended by EPA guidance, the assessment will estimate

contaminant exposures for current as well as hypothetical, future land use scenarios. The

following subtasks, 5.1 and 5.2, describe the components of the baseline human health and

ecological risk assessments, respectively.

Subtask 5.1 - Human Health Baseline Risk Assessment

The human health risk assessment will be conducted in accordance with EPA risk assessment

guidance, including:

L94-437.txt 3

• U.S. EPA Region I Waste Management Division Risk Updates: December 1992.

• Risk Assessment Guidance for Superfund (RAGS), Volume I:Evaluation Manual.

Human Health

(Part A) interim final, 540/1/-89, December 1989.

Development of Risk-Based Preliminary Remediation Goals (Part B) publication 9285.7-01B, December 1991, PB92-963333.

Risk Evaluation of Remedial Alternatives (Part C), publication 9285.7­01C, December 1991, PB92-963334.

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

• Supplemental Guidance to RAGS: Calculating the Concentration Term, (publication 9285.7-081, June 22, 1992).

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

• Final Guidance Data Useability in Risk Assessment (Part A), (publication 9285.7-09A, April 1992, PB92-963356).

• Guidance for Data Useability in Risk Assessment (Part B), (publication 9285.7­09B, May 1992, PB92-963362).

• Dermal Exposure Assessment:91/01 IB, January 1992).

Principles and Applications (EPA 600/8­

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

• Superfund Exposure Assessment Manual.1988. (EPA/540/1-88/001).

Office of Remedial Response. EPA,

• Exposure Factors Handbook. Office of Health and Environmental Assessment. EPA, 1989. (EPA/600/8-89/043).

L94-437.txt

Additional guidance that may be used to prepare and do the risk assessment are:

Guidelines for:

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

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

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

d. The Health Assessment of Suspect Development Toxicants (56 FR 63798, December 5, 1991); and

e. Exposure Assessment Guidelines (57 FR 22887, 1992).

Hazard Identification

In order to identify the data that must be obtained to conduct the risk assessment, TRCC will

review information gathered prior to and during the RI/FS investigation at the site as well as

on current data available through peer-reviewed literature. Most of the data will be from the

ongoing RI/FS investigations, including: (1) sampling results, and (2) discussions in the

previous reports including information regarding local geology, hydrogeology, and fate and

transport. It is assumed that these reports, primarily the Phase 1A - Initial Site

Characterization Report, will provide most of the necessary demographic, geographic,

physical, and biological information to characterize the site for the risk assessment. The cost

estimate allows for limited effort to collect, manage, and analyze these data and to gather any

background information such as status and location of local drinking water supplies, and

current and future land use. The estimate assumes that only sampling data from the current

Phase 1A and IB Initial Site Characterization investigations will be emphasized in the

quantitative risk assessment.

TRCC will evaluate and organize the analytical data specifically for use in the risk

assessment. TRCC will produce summary statistics by medium and/or "hotspot." TRCC

assumes that all data provided to TRCC will be received in a widely-used computer format

L94-437.txt 5

such as DBASE m or ASCII which is compatible with TRCC's software. The cost estimate

for this assignment does not provide for QA/QC or validation of the data provided to TRCC.

Therefore, TRCC will not perform a comparison of the detected contaminants and

concentrations which are presented in the Phase 1A and IB Initial Site Characterization

Reports to those included in the electronic data bases provided. TRCC assumes that all such

data will have undergone QA/QC and will have been validated prior to receipt. The summary

statistics produced by TRCC will require a thorough QA to ensure that all data are accurately

reported. This will be accomplished through a check of all the input parameters (number of

detects, number of samples analyzed, minimum and maximum concentration detected).

The specific tasks TRCC will perform in order to evaluate the data are described below:

1) TRCC will review data to ensure it has been qualified according to acceptable procedures and confirm that all data expected are included and in proper format.

2) TRCC will "upload" data to TRCC software and develop methods for site-specific data analysis (e.g., sample groupings). TRCC routinely enters codes with each sample so that the samples can be distinguished by medium and separated into the appropriate groupings. This task is generally required because of inconsistencies in the sample number designations which are introduced by PRP contractors.

3) TRCC will produce summary statistics by a) determining how data should be grouped, and b) sorting and preparing data for processing by software, c) running programs; and d) formatting output and generating hard copy.

4) TRCC will perform a quality control check of the summary statistics to ensure the program is correct and that all data provided by EPA are properly included and grouped.

5) TRCC will make corrections to the database as a result of any discrepancies noted during the quality control check.

The cost estimate for managing and manipulating the data base assumes a data base of

approximately 330 samples. As discussed during the scoping meeting, the cost estimate also

reflects the assumption that TRCC will receive Phase IB sample analysis data for eight

L94-437.txt 6

ground water and twenty-four soil samples to be included in the quantitative risk assessment

after development of the initial risk assessment data base and submittal of the Pathway

Analysis Report. The cost estimate also assumes that the Phase IB data will agree with

Phase 1A data previously included in the risk assessment data base and will not represent

additional or greater hazards to human health and/or the environment.

Based on information contained in the Statement of Work (SOW) for this assignment any or

all of the following media may be evaluated for the risk assessment.

• ground water • soils (surface 0-2 feet; subsurface 2 feet) • sediments • surface water • air • biota

The final decision to evaluate a specific media quantitatively or qualitatively will be based on

the type and quality of data received, existence of current and potential exposure pathways,

and the availability of appropriate toxicity criteria. The final approach will be discussed with

the EPA prior to implementation.

TRCC will use the available data to identify the contaminants of concern and the range of

concentrations of each chemical detected in the media investigated. TRCC will generate

summary statistics which will indicate for each constituent detected in each medium the mean

and maximum concentrations detected, the location of the maximum detected, and the

frequency of detection. Coded and qualified data will be treated according to

recommendations in RAGS and the EPA Region I Supplemental Risk Assessment Guidance

for the Superfund Program Part 1: Public Health Assessment. Also in accordance with

RAGS, most of these chemicals will be carried through the risk assessment. It is possible

that certain chemicals will be dropped from further consideration after thorough evaluation of

toxicity (carcinogenic and noncarcinogenic), frequency of detection (generally using a cutoff

of 5 percent), average and maximum concentration, persistence in the environment, chemical

L94-437.txt 7

class, and comparison with site-specific background levels. Lack of toxicity data for other

chemicals may permit only a qualitative treatment in the risk assessment. Proposals to omit

chemicals from the risk assessment will be subject to the approval of the EPA. TRCC will

provide EPA with a list of chemicals dropped from further consideration and a brief

discussion of why (i.e., low concentration or toxicity). For chemicals that exceed ARARs or

are contaminants of concern, TRCC will identify regulatory criteria (MCL, MCLG, Vermont

Primary Ground Water Standards, etc.) and the number of times the regulatory criteria are

exceeded.

Also, as part of the Hazard Identification step, TRCC will provide a qualitative discussion on

fate and transport mechanisms derived primarily on information from the Phase 1A report.

Mathematical modeling is not included in the cost estimate for this draft Work Plan and will

only be used if deemed necessary by EPA. The need for modeling of specific pathways (e.g.,

exposures to volatile organics in basements) may need to be reevaluated as data become

available.

The fate and transport evaluation will include physical, chemical, and biological mechanisms.

If chemical interactions affect fate and transport of chemicals from the site, they will be

discussed with the Remedial Project Manager. Where possible, TRCC will discuss present or

potential future offsite migration of contaminants.

Exposure Assessment

For the exposure assessment, TRCC will use available data on chemical releases from the

Burgess Brothers site gathered as part of the Phase 1A and IB investigations to estimate the

actual and potential exposures to human and ecological receptor populations. The exposure

assessment will include determination of:

• contaminant releases • receptor populations • exposure scenarios • exposure doses

L94-437.txt 8

In the first step, release sources for chemical contaminants will be determined to the extent

possible. If appropriate, "hot spots" will be analyzed separately in the risk assessment.

However, TRCC assumes that the number of "hot spots" requiring separate evaluation will be

limited (i.e., one or two analyses).

Chemical concentration data from current Phase 1A and IB investigations will be used in the

risk assessment. Historical data will be discussed where deemed acceptable by EPA and

TRCC and where they are readily available, but will not generally be used in risk

calculations. TRCC will determine the average (arithmetic mean) and maximum chemical

concentrations for each chemical at each exposure point.

For the second step of the exposure assessment, TRCC will characterize potential human

receptor populations in the vicinity of the site. Since this risk assessment will be conducted

to address the "no-action" alternative to remediation, both current and future population data

and distributions will be considered.

Information on contaminant releases, fate and transport, and receptor populations will be

integrated in the evaluation of likely exposure routes. Routes evaluated quantitatively may

include:

• ingestion of ground water, soils, sediments, and biota;

• dermal contact with ground water, soils, sediments, and surface water; and

• inhalation of volatilized ground water contaminants (showering, building infiltration) and soil particulate and volatile emissions.

Final determination of exposure routes will be made on the basis of the sampling results and

future discussion with EPA. For each of the identified exposure routes, scenarios will be

developed as per EPA guidance (i.e., the reasonable maximum exposure for current and/or

future conditions) for each of the identified receptor groups (e.g., workers, residents,

recreational users).

L94-437.txt 9

Assumptions concerning future land use may take into account residential development of the

site under "no-action" conditions. Estimates of parameters such as consumption or intake,

skin surface area, absorption, and body weight will be derived from guidance documents (i.e.,

EPA Region I, RAGS and RAGS 1991 Supplement), when the information is provided, or the

scientific literature. Frequencies of exposure will be estimated on the basis of available

guidance, professional judgment, or site-specific information (if available).

The final step of the exposure assessment will be to produce exposure dose estimates for each

chemical and exposure route. In this risk assessment, quantitative estimates of exposure doses

will be made only if the empirical data are adequate to characterize contaminant

concentrations in a given environmental medium. If this information is unavailable, potential

exposures will be evaluated qualitatively. Doses will be calculated for the reasonable

maximum exposure under both current and future land use conditions.

Toxicity Assessment

TRCC will use information from guidance documents, computerized data bases, and other

sources to describe the lexicological effects to human health from the exposure to each

chemical. Toxicity profiles will be developed for contaminants to provide information on

chemical pharmacokinetics and short-term and chronic toxic effects, including systemic,

reproductive, mutagenic, and carcinogenic effects.

TRCC will also assemble health criteria, where available, for each chemical to be used in the

risk characterization. Where possible, TRCC will use established, route-specific criteria.

Slope factors will be used to evaluate average lifetime exposures to carcinogens. Threshold

criteria based on short-term and chronic (lifetime) exposures will be provided for chemicals

showing noncarcinogenic effects.

L94-437.txt 10

Toxicological information will be gathered from the following sources listed in order of

preferred use:

• Integrated Risk Information System (IRIS), • Health Effects Assessment Summary Tables, and

consultation with EPA staff (ECAO).

Risk Characterization

The final step in the analysis will be to characterize the risk at the site by estimating the

potential for carcinogenic and noncarcinogenic effects based on the calculated exposure doses.

Separate calculations will be performed for current and hypothetical future cases (unless they

are the same, in which case just one set of calculations will be provided).

Dose estimates for carcinogens will be multiplied by slope factors to produce estimates of

incremental carcinogenic risk for each contaminant and exposure route. Carcinogenic risk

values will be summed across contaminants to produce medium-specific risk estimates for

each scenario. When appropriate, medium-specific risks may be summed.

TRCC will assess the potential for noncarcinogenic effects by using a hazard index (HI). The

HI is the ratio of exposure dose to an appropriate toxicity value (e.g., reference dose) which

represents an "acceptable level" of exposure. A ratio greater than one indicates the potential

for adverse effects. Contaminant- and route-specific His will be calculated for exposures to

all noncarcinogens (including carcinogens which lack a slope factor or unit risk). For

contaminants where toxicity values are unavailable, TRCC will evaluate risk qualitatively. If

a hazard index greater than one is calculated for a given exposure pathway, TRCC will sum

hazard quotients across target organs or systems to calculate a hazard index for a given health

effect.

L94-437.txt 11

Uncertainty Analysis

EPA guidance (RAGS) places emphasis on analyzing the uncertainties associated with the

assumptions and inputs used in the risk assessment. Therefore, TRCC will develop an

uncertainty analysis as part of the human health risk characterization discussion. The analysis

will be qualitative in nature and will describe general methodological and site-specific

uncertainties in the risk assessment and, if possible, provide an indication as to whether these

sources of uncertainty have resulted in an over or under estimation of the risk.

Task 5.2 Conduct a Tier-One Baseline Ecological Risk Assessment

TRCC will perform a baseline ecological risk assessment based on information provided in

existing site reports, by contacts with relevant officials, and on information gathered by a

TRCC ecologist during a one-day site visit. If available, applicable information contained in

reports for other Superfund sites in the near vicinity will also be utilized. The ecological risk

assessment will be a screening-level analysis of potential environmental risk (i.e., a Tier 1

analysis) and will consist of qualitative discussions of habitats and species and comparisons of

site concentrations to established toxicity criteria, if applicable. Quantitative measures to

evaluate ecological risks (e.g., wildlife population inventories or biota sampling) are not

included in the cost estimate. The ecological risk assessment will be conducted in accordance

with general EPA ecological risk assessment guidelines including those contained in the

following references:

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

• Ecological Assessment of Hazardous Waste Sites:Reference (EPA 600/3-89/013, March 1989).

A Field and Laboratory

• Ecological Assessment of Superfund Sites; An Overview. Volume I, Number 2. Office of Solid Waste and Emergency Response. EPA, Publication 9345.0-051, December 1991.

L94-437.txt 12

• Developing a Work Scope for Ecological Assessments. Volume I. Number 4. Office of Solid Waste and Emergency Response. EPA, Publication 9345.0-051, May 1992.

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

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

As stated previously, it is assumed that the Phase lA-Initial Site Characterization Report will

provide the necessary geographic, physical, and biological information necessary to

characterize the site for ecological risk assessment.

Media which will be addressed for the ecological risk assessment include:

• surface soils (0-2 feet); • sediments (0-2 feet, if deemed accessible to biota); • surface water; and • biota.

The baseline ecological risk assessment will be divided into the following components:

Hazard Identification (also known as Problem Formulation), Exposure Assessment, Toxicity

Assessment (also known as Ecological Effects Assessment), Risk Characterization and

uncertainty analysis. The Hazard Identification/Problem Formulation will define the

objectives of the assessment, describe on-site and off-site habitats, identify significant habitats

along with rare and endangered species, and provide a regional species profile which

describes and lists flora and fauna species observed or expected to be present in the area. A

description of the site and summary of known or suspected contaminants will have already

been presented in earlier sections of the report, and will not be reiterated in this section.

Primary media of concern, contaminants of concern, and exposure pathways will be addressed

in the Exposure Assessment section. TRCC assumes that sufficient data regarding local

habitats and species (including endangered species) is provided in the Phase 1A Report.

L94-437.txt 13

General information on potential exposure pathways will also be gathered from existing

reports.

The toxicity of contaminants to which environmental receptors may be exposed will be

evaluated in the Toxicity Assessment/Ecological Effects Assessment, if applicable. Toxicity

data will be gathered from on-line data bases and the scientific literature.

Ecological risks will be evaluated qualitatively or quantitatively (depending on the

environmental medium) in the Risk Characterization section. A quantitative assessment of

surface water and sediments may be possible based on the type of data received, the existence

of current and/or potential exposure pathways, and the availability of appropriate toxicity

criteria. A qualitative discussion is anticipated for evaluating risks to terrestrial receptors.

Uncertainties associated with the method used to assess risk to the environment and with site-

specific data will be discussed in the final Uncertainty section.

The need for a more extensive ecological assessment will be discussed with the EPA once all

site data has been submitted and reviewed.

2.6 Task 6 - Public Meeting Support

TRCC will attend and provide technical support and presentations on the findings of the

Baseline Risk Assessment. The attached cost estimate is based on the assumption that TRCC

will attend two meetings in Bennington, Vermont under this task.

3.0 PERSONNEL

Susan Stoloff will serve as project manager for TRCC. The staff listed below are

representative of those who will provide support to EPA for Task 1 of this Work Assignment.

Figure 1 presents the program management structure.

L94-437.txt 14

QUALITY CONTROL COORDINATOR

Edward MacKinnon

TRC ENVIRONMENTAL CORPORATION

PROGRAM REVIEW James Huston

TRC COMPANIES. INC.

PRINCIPAL-IN-CHARGE Vincent Rocco, P.E.

ARCS PROGRAM MANAGER

Paul Hughes

TRCC PROJECT MANAGER

Susan Stolon*

TECHNICAL STAFF

David Fratl Naida Gavrelis

Scott Heim Beth Norman Greg Dripps

Michele Bardier Tracy Jones

•6M/NU

Figure 1-0. Program Management Structure.

15

Professional Name Level Company Title

Paul Hughes P-4 TRCC Program Manager

Susan Stoloff P-3 TRCC Project Manager

David Fratt P-3 TRCC Senior Technical Reviewer

Naida Gavrelis P-3 TRCC Public Health Specialist

Scott Heim P-3 TRCC Ecologist

Greg Dripps P-2 TRCC Toxicologist/Fate and Transport

Tracy Jones P-2 TRCC Environmental Scientist

Beth Norman P-l TRCC Environmental Scientist

Michele Bardier P-l TRCC Environmental Scientist

4.0 SCHEDULE

The schedule for completion of project tasks relies on the timetable for the receipt of

validated data in the appropriate electronic format, the progress of the Phase IB field

investigation, and approval of the Pathway Analysis Report. The dates for project milestones,

discussed during the scoping meeting, are based on the assumption that TRCC will receive all

data in the appropriate electronic format by July 1, 1994 and are as follows:

July 22, 1994 Pathway Analysis Report due to EPA.

L94-437.txt 16

August 5, 1994 Ken Munney's comments on Pathway Analysis Report due to TRCC.

August 12, 1994 Mary Ballew's comments on Pathway Analysis Report due to TRCC.

August 26, 1994* Draft Risk Assessment due to EPA.

September 9, 1994 EPA comments on Draft report due to EPA.

September 30, 1994 Draft Final Risk Assessment due to EPA.

October 14, 1994 EPA comments on Draft Final report due to TRCC.

October 31, 1994 Final Risk Assessment Report due to EPA.

"Due to the short time duration between receipt of May Ballew's comments and delivery of the Draft Risk Assessment, the due date of August 26 is based on the assumption that Mary's comments will be minor. TRCC will work closely with Mary during development of the Pathway Analysis Report to help ensure that this is the case.

4.1 Period of Performance

Effective Date: April 1994

Completion Date: November 1994

5.0 DOCUMENT PRODUCTION

Deliverables produced under this Work Assignment will be the following:

Work Plan Cost Estimate Phase IB Work Plan Review Memorandum Pathway Analysis Report Draft Baseline Risk Assessment Report Draft Final Baseline Risk Assessment Report Final Baseline Risk Assessment Report

L94-437.txt 17

Costs for the production of the above deliverables are included in the cost estimates for the

appropriate tasks. The content and format of the remaining submittals is discussed in the

following paragraphs.

Pathway Analysis Report

EPA has determined a need to review and approve risk assessment inputs and assumptions

prior to preparation of the Draft Risk Assessment Report. These parameters will be

documented in the Pathway Analysis Report, and will include, but not be limited to, the

following:

• Contaminants of Concern,

• Media to be evaluated and treatment (quantitative or qualitative);

• Exposure routes (e.g., ground water ingestion);

• Exposure scenarios (e.g., worker, resident, present/future);

• Exposure inputs (frequency and duration, including references); and

• Dose/response parameters (e.g., potency factors and RfDs, including references).

This report will be submitted to EPA as a formal deliverable and must be approved by the

EPA prior to submittal of the Draft Risk Assessment.

Draft, Draft Final, and Final Risk Assessment Reports

TRCC will prepare a detailed report to describe the methods used for the risk assessment and

the results. The report will fully document the risks associated with the site and the

conclusions made; and, it will generally be organized according to the following outline:

1.0 Introduction Site description and history Summary of site contamination Fate and transport

L94-437.txt 18

2.0 Data Evaluation Data sources Data review Statistical analyses

3.0 Human Health Risk Assessment Selection of contaminants of concern Exposure assessment Toxicity and dose-response assessment Risk characterization Uncertainty analysis

4.0 Ecological Risk Assessment Problem formulation Exposure assessment Ecological effects assessment Risk characterization Uncertainty analysis

5.0 Summary and Conclusions

6.0 References

7.0 Appendices Data Summary Statistics COC selection rationale Toxicity values ARARs and TBCs Toxicity profiles Risk spreadsheets Ecological supporting information

All references will be provided. Toxicity profiles, worksheets, and other documentation will

be included as appendices.

TRCC will submit a Draft Risk Assessment to EPA. Following EPA review of the document,

TRCC will incorporate comments and revisions and submit Draft Final Risk Assessment.

After the public comment period, TRCC will incorporate any additional changes and submit

the Final Risk Assessment. All reports will be submitted in hard copy and on computer

diskette.

L94-437.txt 19

6.0 SUBCONTRACTING PLAN

TRCC anticipates that no subcontractors will be required under this work assignment.

7.0 EXCEPTIONS/ANTICIPATED PROBLEMS

TRCC has developed the estimated schedules and costs based on previous experience with

similar risk assessment projects. Subsequent changes may be necessary, based on new

information from the EPA. TRCC will keep the Remedial Project Manager apprised of any

problems that could impact schedule or budget. The estimated LOE and costs are based on

the task descriptions identified in Section 2.0 of this Work Plan. Additional meetings,

miscellaneous work requests or travel in excess of the anticipated level of effort may result in

the need for work plan revisions in the future. The assumptions used in the development of

the Work Plan and Cost Estimate for this project are summarized below:

TRCC assumes that the Phase IB data will be comprised of eight ground water and twenty-four soil samples and will agree with Phase 1A data previously included in the risk assessment data base and will not represent additional or greater hazards to human health and/or the environment. A larger data set or data that represents different hazards to human health and/or the environment may result in additional costs.

The cost estimate assumes that quantitative measures to evaluate ecological risks (e.g. wildlife population inventories or biota sampling) are not within the scope of the Tier 1 ecological risk assessment.

TRCC assumes that all data provided to TRCC will be received in a widely-used computer format such as DBASE III or ASCII which is compatible with TRCC's software. The cost estimate for this assignment does not provide for QA/QC or validation of the data provided to TRCC.

The proposed schedule presented in Section 4.0 assumes that TRCC will receive all data in the appropriate electronic format by July 1, 1994 and that the period of performance will be extended until November, 1994 to allow for the submittal of the Final Risk Assessment Report on October 31, 1994.

L94-437.txt 20

8.0 QUALITY ASSURANCE

The provisions of the ARCS Quality Assurance program apply to the present Work

Assignment. Work under this assignment may be audited by TRCC's QA staff at TRCC

pursuant to the QA Program Plan. The audit results and any corrective actions will be

described in the Monthly Progress Report and applicable Summary Progress Reports.

A formalized technical review system at TRCC's office applies to most deliverables prepared

under this ARCs Work Assignment. Deliverables will be reviewed by a senior technical

reviewer. Subsequent to that review, a representative of the Quality Assurance staff will

review the document. All resulting comments must be addressed to the satisfaction of the

reviewers.

L94-437.txt 21