9285.9-28
                                    FPA 540/R-94-100
                                    PB95-963213
                                    April 1994
INTRODUCTORY SITE INSPECTION
        TRAINING MANUAL
  Office of Emergency and Remedial Response
    U.S. Environmental Protection Agency
            Washington. DC

-------
                                    9285.9-28
                                    EPA540/R-94-100
                                    PB95-963213
                                    April 1994
INTRODUCTORY SITE INSPECTION
        TRAINING MANUAL
  Office of Emergency and Remedial Response
    U.S. Environmental Protection Agency
            Washington, DC

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                                                                          9285.9-28
                                                                          EPA540-R-94-9W
                                                                          PB95-963213
                                      FOREWORD
This manual  is for reference use of students enrolled in scheduled training courses of the U.S.
Environmental Protection Agency (EPA). While it will be useful to anyone who needs information
on the subjects covered, it will have its greatest value  as an adjunct to  classroom presentations,
involving discussions among the students and the instructional staff.

This manual  has been developed with a goal  of providing the best available current information;
however, individual instructors may provide additional material to cover special aspects of their
presentations.

Because of the limited availability of the manual, it should not be cited in bibliographies or other
publications.

References to products and manufacturers are for illustration only; they do not imply endorsement
by EPA.

Constructive  suggestions for improvement of the content and format of the manual are welcome.

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                INTRODUCTORY SITE INSPECTION  TRAINING
                                          2 Days

This course provides participants with an introduction to the Superfund site assessment process and the
fundamentals of the site inspection phase of this process.  The site assessment process is used to screen
hazardous waste sites for inclusion on the EPA National Priorities List and to prioritize sites for further
investigation and remediation. Participants will receive the background necessary to evaluate preliminary
assessments  and to develop and implement site inspection strategies.  The course is  designed for
individuals with little experience in  the initial evaluation of hazardous waste sites.

The course format is based  on the EPA document entitled Guidance for Performing Site Inspections
Under CERCLA. The focus is on implementing EPA site inspection guidance rather than on emphasizing
the mechanics of scoring sites using the Hazard Ranking System.

Topics to be discussed include an overview of the site assessment process; the fundamentals of the Hazard
Ranking System;  data  collection strategies; site reconnaissance and documentation procedures;  site,
source, and waste characterization techniques; groundwater, surface water, air, and soil exposure pathway
analyses; site inspection approaches; media-specific planning and  sampling strategies; data evaluation and
review;  and reporting requirements.

After completing this course, participants will be able to:

     •    Describe how the outcome of the site assessment process affects the placement of a hazardous
          waste site on the National Priorities List.

     •    Define key phrases related to site inspections.

     •    Review a preliminary assessment document and develop a site reconnaissance plan.

     •    Develop site sampling strategies that will test preliminary assessment hypotheses and will
          provide adequate data for performing Hazard Ranking System calculations.

Note: Calculators are  highly recommended.

Continuing Education Units:  1.35
                                              111

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                                 TABLE OF CONTENTS
Section


Section 1:



Section 2:



Section 3:



Section 4:



Section 5:



Section 6:
Title
Page
Section 7:
Section 8:
Section 9:
Section 10:
Section 11:
Introduction

       Lecture Notes	1-1

Integrated Assessments

       Lecture Notes	2-1

Site Inspection Approaches

       Lecture Notes	3-1

Site Investigation Planning

       Lecture Notes	4-1

Sampling Strategies

       Lecture Notes	5-1

Source Characterization

       Lecture Notes	6-1
       Case Study	6-7

Ground Water Pathway

       Lecture Notes	7-1
       Case Study	7-15

Surface Water Pathway

       Lecture Notes	8-1
       Case Study	8-24

Soil Exposure Pathway

       Lecture Notes	9-1
       Case Study	9-14

Air Pathway

       Lecture Notes	10-1
       Case Study	  10-10

Radiation

       Lecture Notes	'.	11-1

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                               TABLE OF CONTENTS



Section             Title                                                         Page



Section 12:          Site Inspection Evaluation and Reporting

                          Lecture Notes	12-1

Section 13:          Appendixes

                          Appendix A - Fact Sheets
                          Appendix B - Acronym List and Glossary
                          Appendix C - Case Studies
                          Appendix D - SI Data Summary
                                           VI

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 Section 1:
Introduction

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                                • INTRODUCTION •
                                Course Overview

            This course...
               • Focuses on the role of the site inspection (SI) in the site
                assessment process
               • Examines the relationship of the SI to the preliminary assessment
               • Demonstrates that the SI process is flexible and dynamic
               • Describes the activities necessary to develop pathway-specific
                sampling strategies
               • Emphasizes the importance of sampling smart
               • Introduces the concept of "integrated assessments"

            This course will not provide...
               • Detailed SI standard operating guidelines or procedures
               • Hazard Ranking System (MRS) training
                                                                        OH*1
                                SI Guidance Goals

            Assist SI investigators in:
               • Conducting efficient, high-quality assessments
               • Making correct site recommendations
               • Achieving national consistency in performing Sis
         SI Guidance, chapter 1                                              OH • 2
Introduction                                                                       4/94
page 1-2

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                                   INTRODUCTION •
                              SI Guidance Structure
                           Chapter 1 • Introduction
                           Chapter 2 • SI Approaches
                           Chapter 3 • Planning
                           Chapter 4 • Sampling Strategies
                           Chapter 5 • SI Evaluation
                           Chapter 6 • Reporting Requirements
                           References
                           Glossary
                           Appendixes
         SI Guidance, chapter 1
OH* 3
                                  SARA Mandate

               "...assess the relative degree of risk to human health and the
                 environment posed by sites."
         SI Guidance, section 1.1
OH* 4
4/94
  Introduction
     page 1-3

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                                INTRODUCTION •
              Super-fund Tackles Hazardous Waste Emergencies
                      and the Nation's Most Serious Sites
          Site Discovery and Study: Finding the Most Serious Sites
                             Preliminary
                            Assessment
          Long-Term Cleanup:  Fixing the Most Serious Sites

National
Priorities
List







R1/F3


Record of
Decision







Remedial
Design
Remedial
Action






Deletion

0AM

                                                                    OH* 5
Introduction
page 1-4
4/94

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                                INTRODUCTION •
                        The Site Assessment Process:
                         Preliminary Assessment (PA)

                 The PA identifies...
                  • Historical waste generation and disposal practices
                  • Hazardous substances associated with site
                  • Potential sources of hazardous substances
                  • Important migration pathways and affected media
                  • A comprehensive survey of targets
                  • Critical sample locations for SI
        S/ Guidance, section 1.1.1
OH* 6
                        Site Assessment in Superfund
                                             Yes
V.
4/94
                                                                     OH* 7
  Introduction
     page 1-5

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                                • INTRODUCTION •
                         The Site Assessment Process

            Site Inspection (SO
               • Intended to test PA hypotheses
               • Includes collection of environmental samples
               • Involves more detailed data collection
               • Results in a decision to recommend for MRS scoring or no further
                remedial action planned (NFRAP)
         SI Guidance, section 1.1.2                                           OH • 8
                         The Site Assessment Process

            Primary SI objectives
               • Identify substances present
               • Determine whether hazardous substances are being
                released to the environment
               • Determine whether hazardous substances have impacted
                specific targets

            Additional objectives
               • Support potential removal activities
               • Support enforcement actions
               • Collect data to support the remedial investigation/feasibility study
                (RI/FS)
         SI Guidance, section 1.1.2                                           OH • 9
Introduction                                                                      4/94
page 1-6

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                                  INTRODUCTION
                          The Site Assessment Process

                       Major SI activities
                          • Review available information
                          • Organize project team and develop plans
                          • Perform field work
                           - Visually inspect site
                           - Collect data samples
                          • Evaluate all data and prepare site score
                          • Establish defensible documentation
      SI Guidance, section 1.1.2
              OH* 10
                         The Site Assessment Activities
           PA Activities
SI Activities
                                                                       Reporting and
                                                                       Documentation
                                                                        OH* 11
4/94
                    Introduction
                      page 1-7

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                            =     • INTRODUCTION •
                               Comparison of PA and SI
                        PA
                     Limited scope

                     Nonsampling
                     investigation

                     Step-by-step evaluation
                     Comprehensive target
                     survey
                     Conservative assumptions
                     and professional judgment
Limited scope

Biased sampling
investigation

Flexible and dynamic
evaluation

Sampling strategy and
data collection to satisfy
HRS criteria

Additional information to
test critical assumptions
and hypotheses
                                                                               OH* 12
      Notes:
Introduction
page 1-8
                                                                                         4/94

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      Section 2:
Integrated Assessments

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                       INTEGRATED ASSESSMENTS
                          Lecture Overview:
                        Integrated Assessment
                   integrated Assessments and SACM
                  Introduction to the Removal Program
                    Integrated Assessments Approach
                                                           OH»1
                        Integrated Assessments
                  Integrated Assessments and SACM
                   Introduction to the Removal Program
                    Integrated Assessments Approach
                                                           OH* 2
Integrated Assessments
page 2-2
10/94

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                         • INTEGRATED ASSESSMENTS •
                            Integrated Assessments
                Integrating removal and remedial site assessment
                investigation to achieve increased efficiency and shorter
                response times
                One of many programs associated with the implementation of
                the Superfund Accelerated Cleanup Model (SACM)
                                                                      OH* 3
                                 SACM History

                Developed to increase efficiency of the Superfund program by
                streamlining cleanup efforts at all Superfund sites

                Designed to combine immediate action with continuing study as
                necessary

                Should restore public confidence in Superfund process
         Hazard Ranking System Guidance Manual,
         EPA 540-R-92-026, November 1992
                                                                       OH* 4
10/94
Integrated Assessments
            page 2-3

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                          INTEGRATED ASSESSMENTS
                           Traditional Approaches

               Removal assessments are traditionally based on whether site
               conditions meet National Contigency Plan (NCR) criteria for a
               removal action
               Remedial site assessments are focused on collecting data for
               HRS
               The need to integrate these programs is based on the
               assumption that there is duplication of effort between the
               programs
        EPA Directive 9345.1-16FS (Fact Sheet), Integrating Removal and
        Remedial Site Assessment Investigations, September 1993
                                                                    OH* 6
                           Integrated Assessments
                      Integrated Assessments and SACM
                    Introduction to the Removal Program
                      Integrated Assessments Approach
                                                                    OH* 6
Integrated Assessments
page 2-4
10/94

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                        • INTEGRATED ASSESSMENTS
                        What is the Removal Program?

           Federal response capability for releases or threatened releases of:
              • Hazardous substances that present a threat to public health, welfare,
               or the environment
              • Oil spills into or on navigable waters and shorelines
              • Petroleum releases from underground storage tanks
                                                                   OH* 7
                What are the Removal Program Authorities?

           Statutory
             • Clean Water Act (CWA) as amended by the Oil Pollution Act
               of 1990
             • Comprehensive Environmental Response, Compensation
               and Liability Act of 1980 (CERCLA)
             • Superfund Amendments and Reauthorization Act (SARA)
             • Oil Pollution Act
           Regulatory
             • NCP
                                                                   OH* 8
•I 0/94                                                         /irtey/afed Assessments
                                                                        page 2-5

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                          • INTEGRATED ASSESSMENTS •
                           Initiating Removal Actions

            Authority to approve a removal Is generally based on estimated cost
               • Less than 50K - onscene coordinator (OSC)
               • $50K to $2M - regional administrator
               • Over $2M - assistant administrator, OSWER

            PRP search
               • NCR requirement
            Action memorandum
               • Criteria for qualifying site
               • Proposed removal action
               • Estimated cost

         Note: Cost criteria are under revision
                                                                        OH* 9
                           What are Removal Actions?

            Near-term response actions taken to prevent, minimize, or
            mitigate threats to public health, welfare, or the environment
            including, but not limited to:
               • Collection and analysis of samples
               • Provision of alternate water supplies
               • Onsite treatment
               • Source control/stabilization
               • Offsite storage, treatment, destruction, or disposal
               • Temporary relocation of threatened individuals
               • Installation of security fencing/guards
                                                                       OH* 10
Integrated Assessments                                                             10/94
page 2-6

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                           INTEGRATED ASSESSMENTS
                      Classification of Removal Actions

           Classic emergency
              • 33 percent of removal actions since 1985
              • Immediate action required

           Time critical
              • Planning period of less than 6 months
           Nontime critical
              • Planning period of greater than 6 months is available
              • Agency conducts an engineering evaluation/cost analysis
                (EE7CA)

                                                                     OH* 11




How is the Appropriate Response Selected?

Discovery or ^^^^ Removal Site — — — —
Notification Evaluation

^ No release
or threatened
release
Nonfederal party
"™~^ undertaking proper
response
Removal action
fr (removal action
memo to
document a
threat)
^ Remedial
r action
OH


•12
10/94
Integrated Assessments
            page 2-7

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                          • INTEGRATED ASSESSMENTS •
                            The Removal Evaluation

           Removal preliminary assessments and site inspections are
           conducted to determine and evaluate:
              • Presence and magnitude of threat to health or environment
              • Source and nature of the release
              • Activities required to mitigate threat
              • Ability of nonfederal party(ies) to undertake response
              • Need for CERCLA-funded removal
                                                                     OH* 13
                                Removal Criteria

                Actual or potential human or animal food chain exposure
                Actual or potential drinking water contamination
                Fire or explosion threat
                Hazardous substance in containers that pose a threat of release
                Highly contaminated soils at the surface — direct contact threat
                Weather conditions that may cause substances to migrate
                Unavailability of other response or enforcement mechanisms
                                                                      OH* 14
Integrated Assessments                                                           10/94
page 2-8

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              INTEGRATED ASSESSMENTS
           How are Removals Implemented?

Technical response support
   • Technical Assistant Team (TAT) - contractor
   • U.S. Coast Guard (USCG)
   • Environmental Response Team (ERT)
Mitigation/cleanup response
   • Regional Emergency Response Cleanup Services (ERCS) -
    contractor
   • Site-specific contracts

Cooperative agreements (CAs) with states
                                                       OH* 15
                        ERCS
                 Analytical services
                 Containment and countermeasures
                 Cleanup, mitigation, and disposal
                 Site restoration
                                                       OH* 16
                                                            page 2-9

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                        INTEGRATED ASSESSMENTS
                 EPA Emergency Notification Procedures
            The National Response Center (NRC; 1-800-424-8802) alerts
            regional EPA or USCG OSC about most spill notifications
                                                             OH* 17
                        Integrated Assessments
                    Integrated Assessments and SACM
                   Introduction to the Removal Program
                   Integrated Assessments Approach
                                                             OH* 18
Integrated Assessments
page 2-10
                                                                    10/94

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                           INTEGRATED ASSESSMENTS
                     Removal and Remedial Assessments

            Similarities in programs' goals
               • Evaluate potential for human exposure to drinking water, soil,
                and airborne contaminants
               • Evaluate threats to sensitive environments (e.g., wetlands)

            Similarities in activities
               • Telephone and file investigations
               • Site visits or PA recons
               • Sampling visits

        Fact sheet, page 3                                               OH • 19
                     SACM Goals: Integrated Assessment

                Eliminate duplication of effort
                Expedite the process
                Minimize the number of site visits and other steps in the process
                Collect only the data needed to assess the site appropriately
         Fact sheet, page 3                                                OH* 20
10/94                                                           Integrated Assessments
                                                                          page 2-11

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                          • INTEGRATED ASSESSMENTS •
                       Integrated Assessment Approach

                 Important features
                    • Combined notification/site discovery/screening function
                    • Single site visit for both programs
                    • Phased file searches
                    • Integrated sample planning and inspection
               See Figure 2, Integrated Assessment, Integrating Removal
               and Remedial Site Assessment Investigations Fact Sheet,
                        EPA 540-F-93-038, September 1993
         Fact sheet, page 4
OH* 21
                       Integrated Assessment Approach

            Notification/site discovery/screening
               • "One door" notification process
               • All sites screened for emergency response
               • Determine whether there is enough time for a file search before
                initial site visit

            Classic emergency
               • Respond immediately
               • Little or no time for file search or telephone
                investigation
         Fact sheet, page 3
OH* 22
Integrated Assessments
page 2-12
        10/94

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                          INTEGRATED ASSESSMENTS
                      Integrated Assessment Approach
                 File search
                    • Includes all elements of a removal assessment file search
                    • Table 1, File Search and Telephone Investigation, lists
                     elements
                    • Document all elements for both programs
        Fact sheet, page 3                                               OH • 23
                      Integrated Assessment Approach
           Initial field investigation/PA reconnaissance:
              • Combines elements from removal field visit and remedial PA
                reconnaissance
              • Documentation procedures for removal assessment may require
                revision to meet remedial assessment needs
              • Would require onsite reconnaissance at all sites
              • Table 2, Data Elements of the Site Visit, lists data needs for both
                programs
        Fact sheet, page 5                                              OH-24
•I 0/94                                                          Integrated Assossments
                                                                         page 2-13

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                           INTEGRATED ASSESSMENTS
                       Integrated Assessment Approach

           Sample (optional)
              • Should follow current removal assessment approach
              • Should consider MRS data needs

           Review data and decide further action
              • Both programs meet to decide next step(s)
              • May continue removal assessment, PA, or both concurrently
              • May expedite PA to determine whether remedial site assessment
                requirements should be included in sampling plans
         Fact sheet, page 5                                              OH • 25
                       Integrated Assessment Approach

           Complete the PA
              • Collect additional information needed to complete PA
              • Calculate preliminary MRS score
              • Prepare PA report
              • Table 3, Data Elements Needed to Complete the PA, should be
                consulted
              • Refer site to regional decision team if score is greater than or
                equal to 28.5
         Fact sheet, pages 5 and 6                                         OH • 26
Intogntod Assessments                                                          10/94
page 2-14

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                          INTEGRATED ASSESSMENTS
                      Integrated Assessment Approach

           Integrated sampling plan
              • Combines screening level SI plans and remaining removal
               sampling activities
              • For sites going to NPL, remedial project manager (RPM) should
               be consulted
              • Could include sampling for long-term objectives

           Si/removal assessment sampling
              • One event
              • Meet needs of both programs
                  See Table 4, Integrating Removal and Remedial
                   Site Assessment Investigations, Fact Sheet,
                       EPA 540-F-93-038.  September1993
        Fact sheet, page 6                                              OH • 27
                      Integrated Assessment Approach


            Expanded site inspection/remedial investigation
               • Option allowing Rl to start as soon as site appears to qualify for
                NPL
               • NPL listing needs and Rl needs can be incorporated into single
                sampling plan
        Fact sheet, page 6                                               OH»28
•I 0/94                                                          Integrated Assessments
                                                                        page 2-15

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  Section 3:
SI Approaches

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                              • SI APPROACHES  •
                                SI Approaches
                            Yes











Focused
SI
1
t

Expanded
SI


Single
SI





—





|
t

uoc
nt\&
Package
Preparation









or NFRAP




         SI Guidance, chapter 2
OH»1
                              Focused SI: Goals

                Obtain and analyze critical samples
                Investigate human and environmental exposure to hazardous
                substances
                Test PA hypotheses that affect further action recommendations
         SI Guidance, section 2.1
OH-2
SI Approaches
page 3-2
       10/94

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                             •  SI APPROACHES  •
                                 Focused SI
              There are several types of PA hypotheses that would
                        result in a further action decision
        SI Guidance, section 2.1
OH* 3
                                 Focused SI:
                         Further Action Hypotheses
        SI Guidance, section 2.1
                                               Municipal
                                                 Well
OH* 4
10/94
SI Approaches
    page 3-3

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                               SI APPROACHES •
                                 Focused SI:
                         Further Action Hypotheses
                                             Marshes/wetlands
     SI Guidance, section 2.1
OH* 5
                                Focused SI:
                         Further Action Hypotheses
        S/ Guidance, section 2.1
   OH* 6
SI Approaches
page 3-4
                                                                         10/94

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                                SI APPROACHES
                                  Focused SI:
                          Further Action Hypotheses
        SI Guidance, section 2.1
                                               Residence
OH»7
                            Focused SI:  Emphasis

                Additional screening to test "critical" PA hypotheses and
                assumptions
                - Targets that may be exposed to contamination
                - Suspected release of hazardous substances
                - Source characterization and identification of hazardous
                 substances

                Seeks to distinguish between NFRAP and National Priorities List
                (NPL) candidate site
         SI Guidance, section 2.1
 OH* 8
10/94
SI Approaches
     page 3-5

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                                SI APPROACHES
                              Focused SI: Scope

               Average 400 technical hours; typically 350 to 450 hours
               Average 16 samples; typically 12 to 20 samples
               Does not need to satisfy all MRS requirements
               Can reduce number of background samples to control costs
               Number of quality control (QC) and background samples depends
               on pathways being sampled
        SI Guidance, section 2.1
OH-9
                             Focused SI Activities
                           Total Focused SI Hours: 400
         SI Guidance, section 2.1
OH* 10
SIApproaches
page 3-6
                                                                            10/94

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                              • SI APPROACHES  •
                              Focused SI Results
                                     Focused
                                        SI
                               No
                                           Yes
                            Expanded
                               SI
or
                               Expanded SI: Goal
                                                                     OH»11
                     "...collect all data necessary to prepare an MRS
                     scoring package to propose the site to the NPL."
         SI Guidance, section 2.2
                              OH* 12
10/94
                               SI Approaches
                                    page 3-7

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                                 SI APPROACHES
                            Expanded SI:  Emphasis

                Hypotheses or conclusions not adequately documented during
                focused SI
                Collect samples necessary to attribute hazardous substance
                contamination to site operations
                Collect samples to establish background/quality control
                Collect missing data for significant pathways
                Collect all remaining nonsampling data
                Establish thorough and defensible documentation
         SI Guidance, section 2.2                                           OH • 13
                     Expanded SI:  Expanded SI Sampling
                 Design to support HRS requirements
                    • "Observed release" of hazardous substances
                     relative to background
                    • "Observed contamination"
                    • "Levels of contamination"
                 May require special field activities
                    • Monitoring well installation
                    • Air sampling
                    • Geophysical studies
                    • Drum/tank sampling
                    • Borehole installation
                    • Background sampling studies
         SI Guidance, section 2.2                                            OH • 14
SI Approaches                                                                   10/94
page 3-8

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                               •  SI APPROACHES  •
                              Expanded SI:  Scope

                      • Average 600 hours; typically 550 to 650 hours
                      • Average 30 samples; typically 25 to 35 samples
                      • Adequate QC and background samples
                      • Satisfy MRS requirements
         SI Guidance, section 2.2
OH* 15
                             Expanded SI Activities
                                                   Report Preparation,
                                                    MRS Evaluation,
                                                     •nd R«vi«wi
                           Total Expanded SI Hours: 620
         SI Guidance, section 2.2
OH* 16
10/94
 SI Approaches
      page 3-0

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                                 •  SI APPROACHES •

V
SI Approaches: Typical Data Collection Activities
Activity
Nonsampling data
collection
Target sampling
Source sampling
Release sampling
Background sampling
Attribution sampling
QA/QC sampling
Special data collection
or sampling tasks
Focused SI
• (minor activity)
ss (major activity)
ss
s
s
—
S
—
Expanded and
Single SI
/
*v
ss
ss
•/
-------
                                 SI APPROACHES
                              Single SI: Activities
           Scope vanes
              • Collect data to satisfy MRS requirements
              • Obtain adequate QC and background samples
              • Collect missing nonsampling information for significant pathways
              • Document thoroughly
         SI Guidance, section 2.3
OH* 19
                                 SI Approaches

Focused
SI
1
Expanded
SI

Single
SI

—
1
MRS
Package
Preparation
1


or NFRAP

         SI Guidance, chapter 2
OH* 20
10/94
 SI Approaches
     page 3-11

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               Section 4:
    Site Investigation Planning
              Site-specific Work Plan
Health and Safety
  Plan (HASP)
Site Sample Plan
               Investigation-derived
                Waste Plan (IDW)

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                          SITE INVESTIGATION PLANNING
                               Planning - Overview

                              Four plans are needed to:

                              • Refine investigation objectives
                              • Ensure activities proceed efficiently
                              • Ensure safety
                              • Address investigation - derived waste
         SI Guidance, chapter 3, pages 15 and 30                                 OH • 1
                            Sample Collection Issues


                     Demonstrate that hazardous substances are present
                     Determine whether they have migrated from their original
                     locations
         SI Guidance, section 3.1                                              OH • 2
Stto Investigation Planning                                                            11/94
page 4-2

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                            SITE INVESTIGATION PLANNING
                                             SI
                                        Sample Types
                        Waste Source
                          Samples
                   •  Landfills
                   •  Surface impoundments
                   •  Drums/containers
                   •  Piles
                   •  Contaminated soil
Media (Environmental)
     Samples
 •  Groundwater
 •  Surface water
 •  Soil (sediment)
 •  Air
                    Further discussion of sample types is found in Table 3-1,
                        Types of Samples, page 16 of the SI Guidance
      SI Guidance, section 3.1.1
                       OH* 3
      Notes:
11/94
              Site Investigation Planning
                            page 4-3

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                                     TABLE 3-1: TYPES OF SAMPLES
      SAMPLE TYPE
          ADVANTAGES
          DISADVANTAGES
      Biased
      (non-random,
      judgmental)
Promotes timeliness

Uses knowledge of site

Focuses sampling effort
Decreases representativeness

Increases chance of false negatives
      Unbiased
      (random,
      systematic
      grid)
Increases representativeness

Reduces chance of false negatives

Allows limited site knowledge
Increases cost

Increases time required
      Grab
Increases representativeness and
variability
Requires more samples

Requires careful placement
      Composite
Reduces cost

Increases area of investigation

Reduces chance of false positives
Provides average concentrations only

Allows substances to interact
      Media
Supports releases

Supports target contamination
May require off-site access permits

Subject to temporal variation
      Waste
Optimizes contaminant identification

Supports attribution
 May result in elevated concentrations

 May require sample dilution

 May require special procedures and
 equipment
      Filtered
 Allows comparison with drinking water
 benchmarks
 Comparison with surface water
 environmental benchmarks not valid

 May increase sample handling errors
      Unfiltered
 Allows comparison with surface water
 environmental benchmarks
 Comparison with drinking water
 benchmarks not valid
     Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept. 1992
Site Investigation Planning
page 4-4

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                           SITE INVESTIGATION PLANNING
                           Sample Variability:   Factors


                           Sample collection and handling techniques
                           Spatial variability
                           Temporal variability
                            Media variability
      SI Guidance, section 3.1.2, pages 17-21
         OH* 4
                  Sample Variability:  Media-specific Sampling

                              • Surface and ground water
                              • Soil/sediment
                              • Air vapors or particulates
                              • Tissue
                              • Containerized materials
                      Turn to SI Guidance, Table 3-4, Sampling Issues
                    Affecting Confidence in Analytical Results, page 19, for
                              media-specific sampling issues    	
      SI Guidance, section 3.1.2, pages 19-21
         OH* 5
11/94
SJte Investigation Planning
              page 4-5

-------
     TABLE 3-4: SAMPLING ISSUES AFFECTING CONFIDENCE IN ANALYTICAL RESULTS
MAJOR AQUATIC
SAMPLING SOIL/ GROUND SURFACE ANIMAL SOURCE
ISSUES SEDIMENT WATER WATER AIR TISSUE MATERIAL
Hazardous Substance
Migration
Temporal Variation
Spatial Variation .
Topographic and
Geological Features
Hot Spots
Sample Collection
Sample Preparation
and Handling
Sample Storage
Sample Preservation
//
—
//
//
//
/
//
—
—
.
/
—
//
—
/
//
//
//
/
//
//
- 	
—
//
//
//
//
/
//
/
/
—
//
//
//
—
	
/
—
__
—
//
//
//
//
SS
—
//
_
//
/
/
—
—
Key: //= Likely source of significant sampling problem
/ = Potential source of sampling problem
Source: Modified from Keith, 1990
 Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept. 1992
Site Investigation Planning
page 4-6

-------
                         SITE INVESTIGATION PLANNING
                         Field Quality Assurance and
                   Quality Control (QA/QC) Considerations

                Help evaluate quality of analytical results and quality of field
                methods
                QC samples treated in same manner as site samples
                Consult EPA regional guidelines for number and type of QC
                samples to be collected
      SI Guidance, section 3.2, page 21                                       OH • 6
V
      Notes:
                                                            SUt Investfgttlon Planning
                                                                        page 4-7

-------
                          SITE INVESTIGATION PLANNING
                                QC Sample Types
         Co-located or
         Duplicates
         Replicates or Splits
         Field Blanks
         Trip Blanks
         Field Rinsates
         (Equipment Blanks)
         Field Matrix Spikes
Two samples collected at the same time and
location.
One sample that is divided and sent to the
same or separate laboratories.
Samples of contaminant-free medium that are
either transferred from one container to an-
other or are exposed to field conditions.
Samples prepared from contaminant-free
medium and placed in sample containers prior
to the SI. They are kept unopened with site
samples throughout the investigation.
Oeionized water flushed through sampling
equipment after decontamination and before
resampling to monitor decontamination proce-
dures.
Field samples prepared by adding a known
amount of contaminants to selected site
samples.
S/fe Investigation Planning
page 4-8
                                                11/94

-------
                          SITE INVESTIGATION PLANNING
                          HRS Sampling Considerations

               Several MRS elements require sample data
               • Site and source characterization
                - Identify hazardous wastes
                - Determine hazardous waste quantity
                - Delineate source boundaries
               • Observed release and areas of observed contamination
                - Provide direct evidence of an "observed release" to affected media
                - Demonstrate "significant" contamination
                - Estimate  area of contamination
                - Demonstrate "attribution"

      SI Guidance, section 3.3, pages 22-23                                      OH • 7
                            HRS Sampling Considerations

                 Additional HRS elements requiring sample data
                 • Levels of contamination at specific targets
                   - Document "actual contamination"
                   - Targets include drinking water wells, surface water intakes,
                    residential/school properties, and sensitive environments
                   - Support "potential contamination"
                   - Define levels of contamination
                 • Target distances
                   - Establish target distance limits
      SI Guidance, section 3.3                                                 OH •*
11/94                                                           Sto Investigation Planning
                                                                            page 4-9

-------
                         SITE INVESTIGATION PLANNING
                     MRS Sampling Considerations:
                         Levels of Contamination
                               YM
                       Actual contamination
                               Yn
                       LevaM contamination
                        (Target Valuax 10)
      SI Guidance, section 3.3
                                         Potential contamination
                                          (TargatvaluaxO.1)
                                         Laval II contamination
                                          (Target Valuaxl)
OH* 9
                         MRS Sampling Considerations:
                             What are Benchmarks?

                Health- or ecological-based reference concentrations that reflect
                relative risk (for example, cancer risk)
                Media- and threat-specific
                Any threat may involve more than one benchmark
                Found in look-up table (for example, SCDM)
                Default to Level II if no benchmark applies
                        Benchmarks are presented in Table 3-6,
                   Media-specific Benchmarks, S! Guidance, page 23
      SI Guidance, section 3.3
OH* 10
Site Investigation Planning
page 4-10
       11/94

-------
                       TABLE 3-6: MEDIA-SPECIFIC BENCHMARKS
HRS PATHWAY/THREAT
Ground Water
Surface Water
Drinking Water Threat
Human Food Chain Threat
Environmental Threat
Soil Exposure
Air
BENCHMARKS'
Maximum Contaminant Levels
Maximum Contaminant Level Goals
Screening concentrations11'
Maximum Contaminant Levels
Maximum Contaminant Level Goals
Screening concentrations"
Food and Drug Administration Action Levels
Screening concentrations"
Ambient Water Quality Criteria
Ambient Aquatic Life Advisory Concentrations
'Screening concentrations"
National Ambient Air Quality Standards
National emissions standards for hazardous air pollutants
Screening concentrations"
'See Superfund Chemical Data Matrix (SCDM)
'Screening concentrations for cancer corresponding to concentrations for the 10"' individual cancer risk for
oral exposure (inhalation exposure for the air pathway)
'Screening concentration for noncancer lexicological responses corresponding to RfDs for oral exposure
(inhalation exposure for the air pathway)
Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept. 1992
                                                                        Site Investigation Planning
                                                                                      page 4-11

-------
                         SITE INVESTIGATION PLANNING
                            Sample Analysis Options

            Contract Laboratory Program (CLP)

               • Standardized analytical services provided by laboratories under
                contract to U.S. Environmental Protection Agency (EPA)
                • Organics/inorganics
                - Water or solid samples
                - Broad spectrum analysis
                 • target compound list (TCL)
                 • target analyte list (TAL)
      SI Guidance, section 3.4, page 24                                        OH • 11
                            Sample Analysis Options

            Non-CLP services
               • May provide data of similar quality to CLP
               • Analytical protocols must be selected

            Field Analytical Screening Program (FASP)
               • Use "portable" analytical instruments
               • Applications:
                - Screen many samples             - Determine monitoring
                - Select sample locations             well locations
                - Design soil sampling              - Estimate hazardous
                - Determine extent of waste           waste quantity (HWQ)
                 migration                         - Fast turnaround time
                - Reduce CLP costs
      SI Guidance, section 3.4, page 25                                        OH • 12
Slta Investigation Planning                                                          11/94
page 4-12

-------
                          SITE INVESTIGATION PLANNING
                      Review Information for SI Planning

                Compile all relevant and available site data
                - Hazardous waste sources
                - Migration pathways
                - Human and environmental targets
                - Existing analytical data
                Review PA (or focused SI) reports
                - Examine hypotheses
                - Look for changes in site conditions
      SI Guidance, section 3.5                                              OH • 13
V	J
                      Review Information for SI Planning

                       Review data to determine additional work needed
                       -  Data gaps
                       -  Data quality
                       -  Nonsampling information
                       Identify sampling objectives
                       -  Focused vs. expanded SI
                       -  Test critical hypotheses
      SI Guidance, section 3.5                                              OH • 14
                                                              Slt» Investigation Planning
                                                                           page 4-13

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                          SITE INVESTIGATION PLANNING
                       Review Information for SI Planning

                         Other sources of Information
                         • Previous investigations by other parties
                         • Investigations at nearby sites
                         • Removal actions and reports
                         • EPA or other federal agencies
                         • State agencies
                         • Health departments
                         • Academic studies
                         • Owner/operator records

      SI Guidance, section 3.5                                                OH • 15
                         Existing Analytical Data Review

                Use data to support design of sampling and analysis program
                Refer to SI Guidance, Table 3-7, Types of Analytical Data for
                applications of existing data
                SI Guidance, Table 3-8, Review of Previous Analytical Data, sets
                forth a procedure for data review
                SI Guidance, Exhibit 3-1, Checklist for Usability of Previous
                Analytical Data, should be applied to existing data
      SI Guidance, section 3.5.2                                              OH • 16
SIto Investigation Planning                                                           11/94
page 4-14

-------
                        TABLE 3-7: TYPES OF ANALYTICAL DATA
TYPE OF DATA
CLP
Qualified CLP
Non-CLP
Field screening
Owner/operator
APPLICATION
No specific limitations; used as necessary for all SI activities
Some general, limitations depending on types of data qualifiers and bias (e.g.,
unknown, low, high) associated with the data
Few limitations if non-CLP data are shown to be equivalent to CLP data (e.g., level of
QA/QC documentation, level of laboratory performance, level of data quality,
independent data quality review)
Limitations if non-CLP data cannot be shown to be comparable to CLP data
Augments SI samples, especially to investigate area of contamination
Few limitations; used as necessary for all SI activities
Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept. 1992
                                                                    Site Investigation Planning
                                                                                   page 4-15

-------
                     TABLE 3-8: REVIEW OF PREVIOUS ANALYTICAL DATA
PROCEDURE
Determine what data are available
Evaluate purpose and scope of
previous investigations
Review sampling locations, dates,
depths, and sample descriptions
Evaluate the sampling results and
hazardous substance concentrations
Review field preparation and collection
techniques for previous samples
Review available laboratory
documentation
Assess usability of previous data
CONSIDERATIONS
What are the types of previous data: CLP, non-CLP, field
screening, full TCL analysis, partial TCL analysis, owner/operator,
State?
Why were data collected? What type of investigation: State or
Federal facility investigation, enforcement action, emergency
response, RCRA facility inspection, general assessment of ground
water quality, environmental property assessment, NPDES permit
requirements?
Was the design of the sampling program similar to the SI
sampling strategy? Did it include background samples and field
QC samples?
Are a sample plan and sample location map available? Is a field
notebook available that describes all sampling activities?
What hazardous substances were detected? What are the range of
concentrations, background levels, data qualifiers and codes
attached to data, and detection limits?
Were appropriate SOPs used for sample collection and handling?
Are QA/QC procedures or data vab'dation procedures available?
What are the name of the laboratory, the type of analyses
performed, and the performance results?
What is the overall usability of the data set?
  Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept. 1992
Site Investigation Planning
page 4-16

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          EXHIBIT 3-1: CHECKLIST FOR USABILITY OF PREVIOUS ANALYTICAL DATA
 1.   Have samples been taken at the appropriate location, depth, or stratum to confidently
      test site hypotheses?                                                            D Yes   D No

 // the answer is  "no,"  additional sampling will likely be needed to fully test hypotheses
 and provide a basis for the site disposition decision. The data may nevertheless be useful
 in developing  sampling  and analysis  plans  and identifying  hazardous  substances of
 concern.
 2.   Is documentation available to support the analytical procedures used to derive the data
      (e.g.,  laboratory  QA/QC procedures, type of analyses, detection  limits, and data
      review)?                                                                        D Yes  D No
 3.   Are  representative  background  levels  available  for targets  exposed  to  actual
      contamination and hazardous substances that may demonstrate releases?               D Yes  D No
 4.   If background samples are available, are they temporally and spatially comparable to
      samples indicating releases and exposure of targets to actual contamination?           D Yes  D No

 If the answer to questions 2, 3, or 4 is "no." the data may not support HRS documentation
 requirements and further review is needed to determine usability. However, the data may
 support testing of site hypotheses and development of a sampling strategy.
 5.   Do data provide evidence that attributes the hazardous substances detected in various
      media and waste samples to the site?                                              D Yes  D No

 // the answer to question 5 is "no," additional samples will be needed to fully support
 releases and  targets exposed to actual contamination.

 If the answers to questions 1 through 5 are all "yes"  the previous analytical data may
 support  testing  PA  hypotheses,  identification  of hazardous  substances  of concern,
 development  of a sampling strategy, and HRS documentation requirements, including
 releases and  targets exposed to actual contamination.
Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept.  1992
                                                                                   SHe Investigation Planning
                                                                                                   page 4-17

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                          SITE INVESTIGATION PLANNING
                             Site Assessment Team

                             • Site assessment manager
                             • Health and safety officer
                             • Field team
                             • Chemist/data evaluator
                             • Hydrogeologist
                             • Subcontracts officer/procurement officer
                                                                       OH* 17
                                    Work Plan

            Work plans should:

               • Summarize site background and hazards present
               • Identify SI objectives
               • Set work schedule
               • Identify personnel and training needs
               • Determine equipment/laboratory requirements
               • Include provisions to secure contract services
      SI Guidance, section 3.6.1                                              OH • 18
S/fe investigation Planning                                                           11/94
page 4-18

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                          SITE INVESTIGATION PLANNING
                            A Sample Plan Includes:

                Field operations—sequence for conducting field activities
                Sample locations and rationale—sample type, volume, number,
                and sample map
                Analytical requirements and sample handling—sample
                equipment, container types, preservation techniques, and filtering
                Sample delivery—laboratory locations, special storage, and
                transport requirements
                           Refer to SI Guidance, Exhibit 3-2,
                         SI Sample Plan Outline, pages 31-32
         SI Guidance, section 3.6.2                                        OH • 19
                         Health and Safety Plan (HASP)

                  Goal:  To establish requirements and procedures to protect the
                  health and safety of investigative personnel and nearby public

                Routine operations—describe hazards, list key safety personnel,
                levels of protection by task, designate work areas, security,
                environmental monitoring, training requirements, and weather-
                related problems
                Emergencies—communication alternatives, contact procedures
                for emergency response units, emergency equipment, route to
                hospital map, transport vehicles, worker evacuation, and
                decontamination
         SI Guidance, section 3.6.3                                        OH • 20
•11/94                                                           Sto Investigation Planning
                                                                            page 4-19

-------
                              EXHIBIT 3-2: SI SAMPLE PLAN OUTLINE
  INTRODUCTION
       Briefly stale the authority and purpose for conducting the SI and the scope of the investigation.  Discuss
       the objectives and goals of the SI.

  SITE DESCRIPTION AND REGULATORY AND OPERATIONAL HISTORY
    •   Describe the site location.  Identify the type of facility, whether it is active or inactive, and years of
       operation.  Describe its physical characteristics and setting (e.g., local land use, climate, topography,
       geology, hydrology, hydrogeology). Include a map showing the location. Include a site plan or sketch
       showing features on and around the site.

    •   Describe historical site operations, including all past and current operations and conditions. Identify
       current and former owners/operators, types of site activities, wastes generated, and waste disposal
       practices.  Identify all sources and source types.  Provide the hazardous waste quantity disposed in each
       source, if possible, and provide volume or area of the sources. Identify hazardous substances associated
       with or detected in the sources.  Describe source containment Describe any spills  that have occurred at
       the site.

    •   Specify  whether any sources are regulated by RCRA.  Describe past regulatory activities, including
       permits, permit violations, and inspections by local, State, or Federal agencies. If applicable, provide
       emergency response and waste removal information.  Summarize analytical results  of earlier
       investigations. Specify type of data (e.g., CLP, non-CLP, owner/operator).

  COLLECTION OF NON-SAMPLING DATA
    •   Describe additional non-sampling information to be collected (e.g., aquifer boundaries, interconnections,
       and discontinuities; resources; drainage area; soil group; paniculate migration factors) and the rationale
       for collecting this information. Discuss any field activities needed to obtain this information.

   SAMPLING ACTIVITIES
       Discuss objectives of planned field activities. Describe procedures and necessary resources. Discuss the
       rationale for these tasks.

       Provide explicit instructions for all field activities, including field observations, sampling, environmental
       monitoring for health and safety purposes, and field QA/QC protocols.  Reference appropriate Standard
       Operating Procedures (SOPs).  Discuss purpose of both onsite and offsite reconnaissances  and
       observations (e.g., to verify the selection of sample locations, to evaluate the degree of containment at
       site sources, to measure source dimensions, to verify distances  to nearby targets, and to characterize
       additional sources of contamination not identified during previous investigations).

       Justify proposed sample locations. Discuss methods to more fully characterize wastes and sources.
       Identify specific targets to be sampled (e.g., drinking water wells or intakes, fisheries, sensitive
       environments) to test or substantiate target contamination hypotheses.  Describe sampling  strategy to test
       or  substantiate observed release hypotheses and presence of media contamination (e.g., soil, ground
       water, sediment, air, surface water)..
Site Investigation Planning
page 4-20

-------
                      EXHIBIT 3-2: SI SAMPLE PLAN OUTLINE (concluded)
   •   Include a map or siic sketch showing previous and proposed sample locations.

      Summarize sample plan in'a table, identifying sample types, sample numbers, sample locations, and
      sample-selection criteria. Describe methods of sample collection and preservation, field measurements,
      and analytical methods.  Refer to Standard Operating Guidelines (SOGs) or provide a table or checklist
      describing the SOGs.

   •   Describe investigation-derived wastes (IDW) that may result from field activities. Reference the IDW
      plan that describes the management approach  for non-hazardous and hazardous IDW.

 PROJECT MANAGEMENT

   •   Identify all persons who will be involved in the field activities and discuss their  specific
      responsibilities.  Identify all safety and sampling equipment and supplies.  Describe any contractual
      services needed to accomplish field activities.  Summarize all transportation and shipping information.

   •   Describe community relations plans and meetings.

   •   Provide information on SI costs (e.g., number of technical hours; number of CLP, field screening, or
      other samples; subcontracting  costs). Provide schedule for SI activities and deliverables.  Summarize
      any special requirements that impact the SI (e.g., special safety considerations, special analytical
      services (SAS), or special equipment).

   •   Reference the work plan.

 ATTACHMENTS

   •   Sample summary table

   •   Sample location sketch

   •   List of references cited in this plan

   •   Health and safety plan

   •   Appropriate SOPs and SOGs
Guidance for Performing Site Inspections Under CERCLA,  USEPA, Sept.  1992
                                                                           Site Investigation Planning
                                                                                            page 4-21

-------
                         SITE INVESTIGATION PLANNING
            Investigation-Derived Wastes (IDW) Management Plan

                         • Minimize quantity of wastes generated
                         • Remove wastes that pose an immediate threat to
                          human health or the environment
                         • Must comply with applicable federal and state
                          requirements
                      Refer to Directive 9345.3-02, Management
                of Investigation-Derived Wastes During Site Inspections
      SI Guidance, section 3.6.4                                             OH* 21
                             Site Reconnaissance

                        • Verify site conditions
                        • Verify sample locations
                        • Locate and identify all sources
                        • Determine physical state of wastes
                        • Evaluate source containment and migration
                        • Identify overland flow paths
                        • Determine distance from sources to targets
                        • Refine site sketch
                        • Evaluate need for emergency response

      SI Guidance, section 3.7                                              OH • 22
Stto Investigation Planning                                                          11/94
page 4-22

-------
                          SITE INVESTIGATION PLANNING
                                   Site Access

                  "Legal access must be obtained from site owner before
                  conducting an SI"

                Voluntary entry—consent to entry by notifying owner in writing of
                activities to be conducted (sample collection, photography)
                Conditional entry—consent to entry with restrictions (limit area of
                reconnaissance, employee interviews, records)
                Entry with a warrant—SI must be conducted in strict accordance
                with warrant
                Consult with EPA Office of Regional Counsel
      SI Guidance, section 3.7.3                                              OH • 23
V	
            Community, Neighborhood, and Government Contacts

               • Contact local representatives in advance
               • Explain purpose of SI
               • Explain tasks to be performed
               • Identify contact for further information (regional site assessment
                manager—SAM)
               • Determine routing of SI results and other information
               • Consult Community Relations in Superfund: A Handbook, Section
                4.1, OSWER Directive 9230.0-03C, January 1992
               • Contact appropriate municipal, county, state, and federal officials
                before SI

      SI Guidance, sections 3.7.4 and 3.7.5                                      OH • 24
                                                               Site Investigation Planning
                                                                            page 4-23

-------
     Section 5:
Sampling Strategies

-------
                              SAMPLING STRATEGIES
                        SI Sampling Program Purpose...
                                                            Endangered
                                                            species
         ...Assess the nature of the problem site
         ...Support response and further action decisions
         ...Meet public information needs
         ...Incorporate Rl sampling objectives when possible

         SI Guidance, chapter 4
OH*1
      Notes:
Sampling Stntogto
page 5-2
       11/94

-------
                            SAMPLING STRATEGIES
        Bias sampling locations toward areas with potential for hazardous
        substance concentrations higher than background
              •2
           ii
           «!
             r'
                                                       D
                                                         2
                                                        Q
        SI Guidance, chapter 4
    OH* 2
11/94
Sampling Strategies
        page 5-3

-------
                               SAMPLING STRATEGIES
                         Selecting Analytical Parameters
              Review
            Existing Data
    Does
 high quality
analytical data
    exist?
         SI Guidance, chapter 4
                                         i
        Yes
                                    May perform
                                    partial analyses
                                    based on prior
                                    results
Perform full
TCL (TAL)
analyses
                                      OH* 3
                          General SI Sampling Principles

            Sample to:
               • Identify targets exposed to actual contamination
               • Identify all hazardous substances present
               • Demonstrate a release
               • Support attribution
               • Establish representative background concentrations
               • Ensure appropriate QA/QC
         SI Guidance, chapter 4.1.1
                                      OH* 4
Sampling Strategies
page 5-4
                                                                                 11/94

-------
                             SAMPLING STRATEGIES
                       Focused SI Sampling Principles

                  Collect analytical data to tost PA hypotheses
                    • Identify hazardous substances present
                    • Determine whether a release has occurred
                    • Determine impact on targets

                  Determine need for further Investigations
        SI Guidance, chapter 4.1.2                                          OH • 6
                       	J
                    Focused SI Sampling Considerations

                    Concentrate samples on major pathways affecting
                    the score
                    Use previous analytical data
                    Limit collection of background and QA/QC samples
         SI Guidance, chapter 4.1.2                                          OH • 6
11/94                                                              Sampling Stntegtos
                                                                          page 5-5

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                    TABLE 4-2: PRIORITIES FOR FOCUSED SI SAMPLES
SAMPLE BUDGET
CATEGORY
Number of pathways to
evaluate with samples
Number of targets sampled
Number of sources sampled
Number of release samples
Number of background and
QA/QC samples
Other criteria
PRIORITIES
Sample pathways critical to PA further action recommendation
If multiple pathways are critical to screening decision, plan sampling to test
all critical hypotheses
'Sample primary drinking water wells and intakes suspected of exposure to
site-related contamination (see glossary: Primary Target)
Sample nearest targets or targets most likely to be exposed to site-related
contamination for critical pathways if contamination suspected during PA
If sample budget permits, take more than one sample at surface water and
soil target locations that are critical to the site decision
Sample sources to identify hazardous substances present at site
If multiple sources exist, sample each different source type
Sample to test if a release has occurred for critical pathways. When
possible, test release hypotheses in conjunction with target samples
If the magnitude of potentially contaminated targets is responsible for
screening decision, limit number of release samples
Limit collection of background and QA/QC samples to those needed to
screen site. Background or QA/QC samples may not be necessary
Use previous analytical data to plan sample locations
Do not resample at locations where reliable previous analytical data detected
a hazardous substance
 Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept. 1992
Sampling Strategies
page 5-6

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                             SAMPLING STRATEGIES
                 Expanded and Single SI Sampling Principles

           Collect fully documented data to prepare MRS package
              • Document observed releases
              • Document observed contamination
              • Document levels of target exposure

           Collect field data for the Rl when appropriate

           Conduct field activities beyond the scope of focused SI
                         Turn to SI Guidance, Section 4.1.3,
                       page 49, for list of expanded SI activities
        SI Guidance, chapter 4.1.3                                          OH • 7
                   Expanded and Single SI Considerations
                Collect samples to improve documentation for factors that
                significantly affect scoring
                Collect adequate background and QA/QC samples
         SI Guidance, chapter 4.1.3                                          OH • 8
11/94                                                             Sampling Strategies
                                                                          page 5-7

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                         TABLE 4-3: PRIORITIES FOR EXPANDED SI SAMPLES
      SAMPLING CRITERIA
                            PRIORITIES
     Number of pathways
     sampled
Sample pathways critical to site score

If multiple pathways are critical to site score, sample to fully document all
remaining site hypotheses
      Number of targets sampled
Sample targets (e.g., drinking water wells and intakes, residential and school
properties, surface water sensitive environments and wetlands) most likely to
be exposed to site-related contamination

Resample targets where previous analytical results are questionable, or where
background concentrations are needed to document contamination of targets
      Number of sources sampled
Sample sources to attribute hazardous substances to site

Sample to more fully describe areas of observed surficial contamination

If multiple source types exist at site, at a minimum, sample each different
source type
      Number of release samples
Sample to document a release for critical pathways. When possible, collect
samples to document an observed release in conjunction with a target
exposed to actual contamination

Limit number of release samples to critical pathways
      Number of background and
      QA/QC samples
Collect background and QA/QC samples necessary to confidently document
site score
      Other criteria
Use previous analytical data to optimize sample locations

Do not resample at locations where reliable previous analytical data fully
documented a hazardous substance or a release unless samples are needed to
pair those with background samples taken at the same time
    Guidance for Performing Site Inspections Under CERCLA, USEPA. Sept. 1992
Sampling Strategies
page 5-8

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                             SAMPLING STRATEGIES
                 Comparison of SI Data Collection Activities
Activity
Nonsampling data
collection
Source sampling
Target sampling
Release sampling
Background sampling
Attribution sampling
QA/QC sampling
Special data collection
or sampling tasks
FocuMd SI








Expanded and
Single SI








        SI Guidance, chapter 4.1.3
    OH't
                                QA/QC Samples

                Collected to confirm precision and accuracy of data
                QA/QC samples for focused Sis are limited

                - One aqueous trip blank
                - One equipment rinsate blank for each medium collected
                Suggested QA/QC sample guidance for expanded and single Sis
                is found in Table 4-6 (Note: EPA regional guidance may differ)
                           Turn to Table 4-6, Guidance for
                 Minimum QA/QC Samples: Expanded SI or Single SI,
                               page 56, SI Guidance
         SI Guidance, chapter 4.3
   OH* 10
11/94
Sampling Strategies
        page 5-9

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                               SAMPLING STRATEGIES
   Sampled
   SDI
   SD2

   SS1
   SSB
   SW1
   SW2

   SWB
    S1
   GW1
   GWB
                         Mini Exercise: QA/QC Samples
                   GWB
                   SSB
                                                      Small atream
                                                      (10 da)
                                                       S  = source
                                                       SW * surface water
                                                       SO = secSment
                                                       SS = surface toil
                                                       GW = ground water
                                                         0 25ft 50ft
               Sampling Plan
Rationale
Sediment from lagoon
Sediment from probable point
of entry (PPE)
Surface soil from ditch
Surface soil background
Surface water at PPE
Surface water downstream
of PPE
Surface water background
Source (aqueous)
Ground water from private well
Ground water background
                                         QA/QC Samples
                                 Focused SI
Expanded SI
                                                                          OH* 11
StmpllngStntogto*
page 5-10
                                                                                  11/94

-------
                           SAMPLING STRATEGIES
               Demonstrating a Release: HRS Requirements
                  An observed release can be documented by:
                             • Direct observation

                             • Chemical analysis
        SI Guidance, chapter 4.4.1
   OH* 12
                   Demonstrating a Release by Sampling

Key Factor To demonstrate a release by chemical analysis
for a pathway, at least one sample must show
contamination significantly above the background
level for a hazardous substance

See SI Guidance, page 59, for a discussion of the term "significance" 1
SI Guidance, chapter 4.4.1 OH • 1 3

J
11/94
Sampling Strategies
       page 5-11

-------
                           SAMPLING STRATEGIES
                  Demonstrating a Release by Sampling

                          77»ree Primary Factors
            Background
Attribution
Target
                        Document observed release
                           (actual contamination)
        SI Guidance, chapter 4.4.1
                                OH* 14
            Demonstrating a Release by Sampling:  Background

           Considerations
             • Naturally occurring vs. man-made concentrations
             • Chemical analytical data vs. published data
             • Comparability of background and release samples
             • Background sampling locations
        SI Guidance, chapter 4.4.1
                                 OH* 16
Sampling Sfnrtogft
page 5-12
                                                                       11/94

-------
                             SAMPLING STRATEGIES
             Demonstrating a Release by Sampling: Attribution

           Considerations
              • Some portion of the release must be attributable to one or more
                sources
              • Can use a unique hazardous substance from a site to
                differentiate it from other sites
              • May be addressed by source characterization
        SI Guidance, chapter 4.4.1
         OH* 18
                 Background
                  Sample
                "non-detects"
                                  Attribution?
                               1.2DCE
                               Benzene
                               Toluene
                               Xylene
Source
Sample
Benzene
Toluene
Xylene
                                                   Release
                                                   Sample
                                                   1.2DCE
                                                   Toluene
                                                                     OH* 17
11/94
      Sampling Strafogfes
             page 5-13

-------
                             SAMPLING STRATEGIES
                Demonstrating a Release by Sampling:  Targets

            Evaluate target factors
              • Nearest individual
              • Population
              • Sensitive environments, including wetlands

            Evaluate on the basis of:
              • Actual contamination
              • Potential contamination
         SI Guidance, chapter 4.4.1                                         OH • 18
                     Demonstrating Actual Contamination

                Must first demonstrate observed release
                Targets exposed to concentrations meeting observed release
                criteria are evaluated as actually contaminated
                Two degrees of actual contamination
                - Level I = concentration > applicable benchmark(s)
                - Level II = concentration < applicable benchmark(s)
         57 Guidance, chapter 4.4.1                                          OH • 19
Singling Stntogtos                                                               11/94
page 5-14

-------
                          • SAMPLING STRATEGIES
                           Actual Contamination?
                            Concentrations (in ng/L)
Analyte
Compound x
Site
25
Background
5U
Intake
20
Benchmark
15
          U = nondetect
                                                                  OH -20
                     Sampling Strategies:  Conclusions

              The key to any successful $1: sample smart
              • Conserve resources
              • Set sampling priorities
              • Emphasize dual-purpose sampling
              • Use previous analytical data to augment scope
              • Tailor sampling to meet SI objectives
              • Consider MRS math when planning samples
               • Focus on major pathway(s)
               - Focus on critical MRS factors
                                                                  OH* 21
11/94
Stapling Stntogto
       page 5-15

-------
      Section 6:
Source Characterization
                     D
                     D
                     D
o

-------
                           SOURCE CHARACTERIZATION
                                Source Definition
                "An area where hazardous substances may have been
                deposited, stored, disposed of, or placed. Also, soil that
                may have become contaminated as a result of hazardous
                substance migration."
         SI Guidance, glossary, page 121
OH*1
                                Basic Principles

            Sample to confirm OF refute contamination at site

            Sample to characterize sources
               • Identify hazardous substances present
               • Support determination of waste characteristics
               • Support attribution
         SI Guidance, section 4.2
OH* 2
Source C/Mractarfzatfon
page 6-2
                                                                               4/04

-------
                           SOURCE CHARACTERIZATION
                                    Guidelines

               • Sample as many different types of sources as possible
               • Sample visibly contaminated soil near drums or containers—do
                not sample drums or containers themselves
               • Sample within 2 feet of ground surface (soil exposure pathway
                considerations)
               • Sample where wastes are likely to collect or be concentrated
               • Collect background sample for selected sources (for example,
                contaminated soil)
               • Use composite samples carefully
         SI Guidance, section 4.2                                             OH • 3
      Notes:
4/94                                                              Source Characterization
                                                                            page 6-3

-------
                         SOURCE CHARACTERIZATION
                         Source Characterization
                 8
                 0)
                                                         D
                                                         D
                                                                 OH* 4
Source CfMracfarfzatfon
page 6-4
                                                                        4/94

-------
                          SOURCE CHARACTERIZATION
                              Focused SI Strategy
              • Primary objective is identifying hazardous substances present at
                the site
              • Should not attempt to establish degree of containment of
                source(s)
              • Source area, volume, and hazardous constituent estimates are
                beyond the scope of focused SI
         SI Guidance, section 4.2.1                                           OH • 5
                                                                  	J
                       Expanded and Single SI Strategy

                Emphasis is on MRS documentation requirements
                May not need further characterization after focused SI
                May collect samples to document containment
                Generally, do not collect samples to document extent of
                hazardous waste contamination
         SI Guidance, section 4.2.2                                           OH • 6
4/94                                                             Source Chanctartzalton
                                                                           page 6-5

-------
                           TABLE 4-4: SOURCE SAMPLING STRATEGIES
       CRITERION
       FOCUSED SI
     EXPANDED SI AND SINGLE SI
   Primary objective
To identify hazardous
substances associated with site
sources; to confirm substances
known or suspected

To refine target distance limits
To verify inconclusive data collected during
focused SI

In limited situations, to help quantify hazardous
waste quantity
   Data quality
All DUCs
DUC-I for hazardous constituent quantity

DUC-I and DUC-II to establish heterogeneity
or homogeneity of wastes

All DUCs for other hazardous waste quantity
measures and to identify hazardous substances
associated with site sources
   Samples to help
   demonstrate observed
   contamination
Generally limited to samples
used to test a site hypothesis
regarding soil contamination
within 2 feet of surface
Samples to further describe the areas of
observed contamination in the direction of
targets for the soil exposure pathway
   Samples to help
   evaluate source
   containment or source
   type
Generally not collected
 Generally only collected when the containment
 factor value for a migration pathway is not 10;
 sometimes collected to demonstrate a biogas
 release if air pathway is  significant pathway
   Samples to help
   describe source
   boundaries and estimate
   hazardous waste
   quantity
 Generally limited to surficial
 samples within 2 feet of
 surface

 Generally limited to
 contaminated soil sources
 In certain situations, samples to estimate the
 depth of a source or to further describe the
 area of sources other than contaminated soil
 (e.g., landfill, land treatment, buried surface
 impoundment)

 In certain situations, samples to estimate
 hazardous constituent quantity or hazardous
 waste volume quantity
  Guidance for Performing Site Inspections Under CERCLA, USEPA. Sept.  1992
Source Characterization
page 6-6

-------
                            SOURCE CHARACTERIZATION
                                    CASE STUDY

                     EXAMPLE OF SOURCE SAMPLING STRATEGY

Located near a town of 10,000 people, the Lakefield Farm Site is an abandoned strawberry
farm that was used for various types of waste activities for an unknown period (see Lakefield
Farm Site Sketch #1).  During the preliminary assessment, three potential sources were identi-
fied: a wet surface impoundment with a volume of approximately 45,000 cubic feet of electro-
plating sludge; a drum storage area containing about 30 leaking drums (contents unknown) at
the southeast comer of the site; and an area of stained soil near the site's western boundary.

                             Lakefield Farm Site Sketch 1
                         Surface Impoundment
                             (Sludge)
           -f
                                                   ' A Neircil Well and
                                                   (\   Ncar«l
                                                   I—I  Individual
                                                           LAKEFIELD
                                                           FAnM SITE
Suincd Soil
                                                     GREENACRES
                                                     SUBDIVISION
                KEY

             • Source samples

             -^- Drinbng water well                         Municipal Well        	ft 	


             -<}>- Irrigition well                               ~^f~

                                                                     NOT TO SCALE
4/94                                                                Source Characterization
                                                                               page 6-7

-------
                            SOURCE CHARACTERIZATION
                  SOURCE SAMPLING STRATEGY FOR EXAMPLE SITE
   Potential Waste
    Source Area
      Focused SI
   Sampling Strategy
        MRS
    Considerations
    Nonsampling
   Data Collection
Wet surface
impoundment
Collect one composite
source sample of
impoundment sediments
(SD-1) plus one sludge
sample (SL-1) to
evaluate hazardous
substances present
More than 675,000
cubic feet is needed to
increase HWQ factor
to next category value
Obtain physical
dimensions of
source: evaluate
containment,
consider using aerial
photographs
Drum storage area
Collect one composite
surficial soil sample
(SS-1) from beneath
drums to determine
hazardous substances
present
More than 1,000
drums are needed to
increase HWQ factor
value to next category
value
Verify number of
drums, evaluate
containment, look for
container markings,
examine area around
drums
Stained soil
Collect one composite
surficial soil sample
(SS-2) to determine
whether area is
contaminated and to
identify hazardous
substances
More than 78 acres of
contaminated soil are
needed to increase
HWQ factor value to
next category value
Obtain physical
dimensions of area,
evaluate containment
  Source Characterization
  page 6-8
                                                                              4/94

-------
                   Section 7:
           Ground Water Pathway
Resources
          Wellhead
          protection
           area
Nearest
 well
                                      \
                        SOURCE
Ground water
 population
           /\
      '•V""1""/
                        AQUIFER

-------
                           GROUND WATER PATHWAY
                           Ground Water Pathway

           Basis for pathway score
              • Number of people served by each aquifer
              • Likelihood of release to each aquifer
              • Likelihood that drinking water wells are contaminated
               by site
        SI Guidance, section 4.5                                          OH • 1
               Ground Water Pathway: Review PA Information

           Determine whether major pathway of concern is based on:
              • Suspected release
              • Primary targets
              • Number of secondary targets

           Has contamination already been demonstrated?
              • Previous sampling
              • Reports of suspected release
              • Number of secondary targets

                                                                    OH* 2
Ground Water Pathway                                                          4/94
page 7-2

-------
                            GROUND WATER PATHWAY
               Ground Water Pathway:  Review PA Information

             Identify specific information concerning primary targets
             - Type of well/population served
             - Distance from sources
             - Depth of screened interval
             Identify wellhead protection areas
            • Identify relevant hydrogeological information
            ' Identify potentially affected resources
             Where do you expect hazardous substances to be found?
             (sinkers vs. floaters)

                                                                      OH* 3
                                       	J
                            Ground Water Pathway

            Compile existing analytical and nonsampling information

            SI data summary document can be used to:
               • Summarize existing information
               • Identify factors not fully evaluated
               • Focus additional data collection efforts
                  Turn to SI Guidance, Appendix B, SI Data Summary
         SI Guidance, appendix B                                            OH • 4
4/94                                                             Ground Water Pathway
                                                                           page 7-3

-------
                         GROUND WATER PATHWAY
                         Ground Water Pathway:
                           MRS Considerations
         Waste
   Characterization
    Likelihood
    of Release
      Conducted under
   source characterization
Demonstrate/document
       release
  Targets
   Actual
contamination
     vs.
  potential
contamination
                                                               OH-5
                         Ground Water Pathway:
                          Likelihood of Release
                       Document an observed release by:
                         • Direct observation
                         • Chemical analysis

                       Chemical analysis is preferred
        SI Guidance, section 4.5
                                     OH* 6
Ground Water Pathway
page 7-4
                                                                      4/94

-------
                        • GROUND WATER PATHWAY
                          Ground Water Pathway:
                           Likelihood of Release

             • At least two groundwater samples are needed to document
              an observed release

              • Background sample
              • Release sample

             • Well samples should be from same aquifer and comparable
              screened intervals


             • Wells should be of similar construction
                                                                OH»7
V.

4/94
               Ground Water Pathway:  Likelihood of Release
                            Observed Release?
                 Contaminated
                 well sample
            200'
Background
well sample
                                                                OH* 8
          Ground Water Pathway
                    page 7-5

-------
                           GROUND WATER PATHWAY •
                           Ground Water Pathway:
                            Likelihood of Release

               Sample nearest well expected to be contaminated
               Background well should be out of influence of site
               Sample both wells within 1-3 days
               Samples should be similar
               - sample analyses
               - filtered or unfiltered
        SI Guidance, Section 4.5                                           OH • 9
                            Ground Water Pathway:
                                    Targets

                PA primary targets are sampled to establish "actual
                contamination"
                PA secondary targets become "potential contamination"
                                                                     OH* 10
Ground Watof Pathway                                                            4/94
page 7-6

-------
                         • GROUND WATER PATHWAY •
                           Ground Water Pathway:
                                   Targets

               Ground water pathway targets
               - Municipal drinking water wells
               - Private drinking water wells
               - Public drinking water wells
               Always sample nearest target well
               Attempt to sample all primary targets
               Cannot infer contamination between wells for actual
               contamination
V.
/"
        SI Guidance, section 4.5
     OH* 11
                           Ground Water Pathway:
                   Ground Water Sampling Considerations
                                                                   OH* 12
4/94
Ground Watar Pathway
          page 7-7

-------
                          GROUND WATER PATHWAY
                          Ground Water Sampling
Type of Well
Monitoring
Private
Municipal
Industrial
Irrigation
Standby
Background






Observed
Release






Actual
Contamination






                                                                  OH* 13
                          Ground Water Pathway:
                        Focused SI Strategy-Release

           If PA hypothesized release to groundwater
              • Sample to test hypotheses
              • Sample nearest drinking water well
           Sampling to establish and document an observed release not
           necessarily in scope of focused SI
              • Background wells may not be available
              • Wells near source(s) may not exist
              • Monitoring wells are an expanded SI activity
           Can use other sources to establish background if necessary

        SI Guidance, section 4.5.1                                        OH • 14
Ground Water Pathway
page 7-8
                                                                          4/94

-------
                           GROUND WATER PATHWAY
                           Ground Water Pathway:
                        Focused SI Strategy-Targets

               Not every primary target well must be sampled
               Sample wells where detection of hazardous substances is likely
               Sample critical well locations
               Target well - drinking water well
               Background well = any type of well
               Some wells can serve as their own background wells if
               continuous monitoring data are  available
        SI Guidance, section 4.5.1                                         OH • 15
                           Ground Water Pathway:
                  Focused SI Strategy-Actual Contamination

           If "actual contamination" is hypothesized
              • Drinking water wells should be sampled
              • If all wells cannot be sampled, sample nearby and municipal wells
              • Sample remaining wells during expanded SI
           Can use samples from target wells to demonstrate observed
           release and actual contamination
        SI Guidance, section 4.5.1                                         OH • 1 6
4/94                                                           Ground Water Pathway
                                                                         page 7-9

-------
                          GROUND WATER PATHWAY
Which Wells Should Be Samp
to Test for Actual Contaminati
Source JTN
A\ /±N A\
s>

V
led
on?
(t) Private Wd
4Q Industrial Witt
0 OJ
l J
1 1
•catolnmttM

OH«17

                          Ground Water Pathway:
                   Focused SI Strategy-Blended Systems
                                                Wells A, B, and C are
                                                part of a blended
                                                system. Which wells
                                                should be sampled.
        S/ Guidance, section 4.5.1
OH* 18
Ground Water Pathway
page 7-10
                                                                        4/94

-------
                          • GROUND WATER PATHWAY •
                     Expanded SI and Single SI Strategy
          Review existing analytical data
          from wells in the vicinity
          of the site
             • Check for abnormalities
             • Determine need for resampling
        SI Guidance, section 4.5.2
ABC Site: Analytical Data
  Samples    Results
                                                        /*•»•
                    OH* 19
                     Expanded SI and Single SI Activity:
                        Document Observed Release

               Resample wells as needed
               Sample wells not tested during focused SI
               Collect background samples
               Install monitoring wells
               Collect QC samples
                                                                   OH* 20
4/94
                Ground Water Ptthway
                          page 7-11

-------
                            GROUND WATER PATHWAY
                      Expanded SI and Single SI Activity:
               Ground Water Target Sampling Considerations

              • "Actual contamination" requires an observed release, attribution,
               and presence of hazardous substance at target
              • Collect QC samples
              • Base well selection on ground water flow direction
              • Background well should be upgradient or at least outside of the
               influence of sources
              • Focus on targets
v        SI Guidance, section 4.5.2                                         OH«21      /
                      Expanded SI and Single SI Activity:
                          Monitoring Well Installation

               Done only on sites expected to score because of observed
               release
               May not be necessary if ground water pathway is not critical site
               score
               Do not install wells in karst aquifers
        SI Guidance, section 4.5.2                                          OH • 22
Ground Water Pathway                                                            4/94
page 7-12

-------
                 TABLE 4-8: GROUND WATER SAMPLING STRATEGIES
CRITERION
Primary objective
Data quality (see
section 5.2)
Average number of
samples
Types of activities
Background samples
Attribution samples
QA/QC samples
FOCUSED SI
To test hypotheses regarding a suspected
release or targets suspected to be exposed
to actual contamination
When possible, test release hypothesis in
conjunction with target sampling
Less rigorous (e.g, DUC-II) to rigorous
0 to 6 depending on site hypotheses and
number of existing wells to sample
Sample existing wells
Install drive points or shallow boreholes
if there are no nearby wells
Limited, 1 background per 3 release
samples
May rely on published regional data
Limited to testing release hypotheses
Limited to testing release hypotheses
EXPANDED SI AND SINGLE SI
To demonstrate a release based on HRS
documentation requirements
To demonstrate targets exposed to actual
contamination and determine levels of
exposure
Rigorous (e.g., DUC-I)
0 to 14 based on HRS documentation
requirements
Resample existing wells if previous data
did not conclusively demonstrate a release
or targets exposed to actual contamination
Sample wells not yet sampled
Collect multiple samples from drinking-
water wells where hazardous substance
concentrations are likely to be near
benchmarks
Install monitoring wells as needed
2 background per 3 release samples
Install background monitoring wells, if
necessary
Generally should not rely on published
data
Those necessary to attribute a share of a
release to the site
Those necessary to obtain precise and
accurate data.
Guidance for Performing Site Inspections Under CERCLA, USEPA, Sept.  1992
                                                                      Ground Water Pathway
                                                                                  page 7-13

-------
                          GROUND WATER PATHWAY
                          Ground Water Pathway
             • After sampling and analysis have been completed, compile new
               information
             • Complete SI data summary sheets pertaining to ground water
                 Turn to SI Guidance, Appendix B, SI Data Summary
                                                               OH* 23
        Notes:
Ground Wafer Pathway
page 7-14
                                                                          4/94

-------
                              GROUND WATER PATHWAY
                                     CASE STUDY

         EXAMPLE OF GROUND WATER SAMPLING STRATEGY: FOCUSED SI

During the PA it was determined that residents near the Lakefield Farm Site rely on shallow
domestic wells for drinking water (see Lakefield Farm Site Sketch 2). A municipal well that
provides drinking water to about 10,000 people is located 0.5 miles southeast of the site.  The
municipal well and several nearby irrigation wells are screened in the deep aquifer, which
appears to be interconnected with the shallow aquifer. The PA identified the primary targets
as all domestic wells within 0.25 miles of the site and the municipal well.  The focused SI
indicated ground water flows to the south. Several domestic wells appear to be downgradient
from the site.
                             Lakefield Farm Site Sketch 2
                                              GW-l
                                                      GW-2
                                        SL-1
                                  SD-1
                                              SS-l
                                              GW-4
                                                                      Director, of
                                                                     groimdwaicr flow
                                         A
                                        Q
Netrcsi
 Well
                                                        LAKEFIELD
                                                        FARM SITE
                                GW-9
KF.Y_
Drinking W»ier SVell
Source Simple
Irrigilion Well
                                   GW-6    GW-7   GW-S

                                        GREENACRES
                                        SUBDIVISION
                               GW-10    GW-H
                                                    Municipal Well
                                                      GW-n
4/94
                 1


              —N —



            NOTTO SCALE

            Ground Water Pathway
                       page 7-15

-------
                       GROUND WATER PATHWAY
         GROUND WATER SAMPLING STRATEGY FOR EXAMPLE SITE
                            FOCUSED SI
Samples
Municipal wen (GW-12)
Domestic weto (GW-3,
GW-4, GW-5. GW-6,
GW-7, GW-8. GW-9.
GW-10, GW-11)
Background (GW-1,
GW-2)
Sources (SD-1, SL-1,
SS-1, SS-2)
Quality control (Q-1.
Q-2) (not shown)
Focused SI
Sampling Strategy
Collect sample prior to treatment;
sample to document
contamination, identify hazardous
substances, and determine level
of contamination
Sample nearest domestic drinking
water wells suspected of exposure
to contamination
Sample drinking water aquifer
limit number of background
samples
Collect grab or composite soil
samples to identify hazardous
substances present at site
Monitor sample collection and
decontamination procedures; one
rinsate and one field blank
MRS
Considerations
Determine municipal well
contamination, which is critical
to protecting public health and
the screening decision
Determine domestic wel
contamination, which is critical
to protecting public health and
the screening decision
Sample to determine
concentrations of hazardous
substances
Do not sample to increase
hazardous waste quantity
(amounts are not dose to HWQ
factor value breakpoints)

Nonsampfing
Data Collection
Verify aquifer from which wel
draws; verify population
served
Verify aquifer from which weto
draw, verify population served
Verify aquifer from which well
draws
Obtain physical dimensions of
surface impoundment and
estimate area of contaminated
soO; verify number of drums
and look for drum labels

Ground Water Pathway
page 7-16
                                                                 4/94

-------
      Section 8:
Surface Water Pathway

-------
                          • SURFACE WATER PATHWAY •
                            Surface Water Pathway

           Score based on:
              • Likelihood of release to a surface water body
              • Likelihood that surface water is contaminated by the site
              • Number of people exposed to contaminated drinking water or
                contaminated food items
              • Sensitive environments exposed to contaminated water
         SI Guidance, section 4.6
OH*1
                            Surface Water Pathway
                 Key Factor   If there are no surface waters within 2 miles of
                              the site, the surface water pathway need not be
                              evaluated
         SI Guidance, section 4.6
OH* 2
Surface Water Pathway
page 8-2
                                                                              10/94

-------
                           SURFACE WATER PATHWAY
                           Surface Water Pathway

           Examples of surface water bodies

              • Perennially flowing ditches, streams, and rivers
              • Isolated but perennial ponds or lakes (excludes man-made used
               for industrial purposes)
              • Intermittent streams only in areas with less than 20 inches mean
               annual precipitation
              • Natural and man-made wetlands
        SI Guidance, section 4.6
                                 OH* 3
                   How Contaminants Reach Surface Water
          Overland flow
          Flood
        • Ground water
          discharge to surface
          water


        SI Guidance, section 4.0
Runoff
                                          •ourc*
                                   Runoff
      SOUK*
                                  OH*4
10/94
                           Surface Water Pathway
                                     page 8-3

-------
                            SURFACE WATER PATHWAY
                        Surface Water: Multiple Targets
                 Waste
              Characteristics
Likelihood
of Release
         SI Guidance, section 4.6
                                                         Drinking






1MB




•^H
Water

Human Food
Chain

Environmental
Thraa*
                                    OH* 5
                     Surface Water Pathway Investigation
                       Complete the SI Data Summary Surface
                         Water section using available data
                     See SI Guidance, Appendix B, Surface Water
                     Information Section, pages B-12 through B-15
         SI Guidance, appendix B
                                    OH* 6
Suffice WttorPtthwty
page 8-4
                                           10/94

-------
                            SURFACE WATER PATHWAY
                            Review PA Information

           Determine whether major pathway of concern is based on:
              • Suspected release
              • Primary targets
              • Number of secondary targets
         SI Guidance, section 4.6                                            OH • 7
        	J
                             Review PA Information

            Identify physical characteristics of surface water migration route
               • Is overland segment greater than 2 miles?
               • Are there multiple watersheds?
               • Location of PPE(s)
               • Tidal influence
               • Flow rate for each segment of migration path
         SI Guidance, section 4.6                                            OH • 8
10/94                                                            Surface Water Pathway
                                                                          page 8-5

-------
                            SURFACE WATER PATHWAY •
                            Review PA Information

           Identify locations of primary targets
              • Drinking water intakes
              • Fisheries
              • Wetlands and other sensitive environments
         SI Guidance, section 4.6                                             OH • 9
                   Surface Water Sampling Considerations

              • Are sources actively discharging contamination to surface water?
              • How old is the site?
              • What are surface water flow characteristics?
              • What are the chemical properties of hazardous substances of
               concern (for example, persistence and bioaccumulation
               potential)?
         SI Guidance, section 4.6                                            OH • 10
Surface Water Pathway
page 8-6

-------
                         • SURFACE WATER PATHWAY •
                       Sample Type Considerations

         Sediment, Aqueous, or Tissue
            • Sediment samples typically detect contamination more often than
              other sample types
            • Consider adding aqueous samples for intakes or sensitive
              environments
            • Tissue samples are generally not recommended
        SI Guidance, section 4.6                                          OH • 11
                                            	J
                            Likelihood of Release:
                  Observed Release By Direct Observation

           Hazardous substance seen entering or known to have been
           deposited into perennial surface water
              • Sample effluent discharge, source runoff, or leachate (no
                background required)
              or
              • Rely on existing analytical data indicating effluent contains
                hazardous substance
              • Must sample discharge, runoff, or leachate to show they contain
                hazardous substance


        SI Guidance, section 4.6                                          OH • 12
1 o/94                                                          SuiftK* Wttor Pathway
                                                                         page 8-7

-------
                           SURFACE WATER PATHWAY
                           Likelihood of Release:
                  Observed Release By Direct Observation

           Source area flooded and hazardous substances In direct contact
           with flood waters
              • Must rely on historical "source" data and flood information
              • No SI sampling necessary
        SI Guidance, section 4.0                                         OH* 13
                           Likelihood of Release:
                  Observed  Release By Chemical Analysis

               Minimum of two samples
               - One background sample upstream from PPE
               - Second sample at or reasonably close to PPE (downstream
                sample)
               If multiple PPEs present, sample each
               Background and release samples must be same type and from
               same or similar water body
        SI Guidance, section 4.6                                         OH • 14
Surface Water Pathway                                                         10/94
page 8-8

-------
                          SURFACE WATER PATHWAY •
                    Sample to Establish Background
                                 Wetland
             Landfill
                        Bald eagle
                           habitat
                 Key
      Flow direction

      Intermittent stream  	
                                                                OH* 15
10/94
Sufftc* Water Pathway
          page 8-9

-------
                 33    • SURFACE WATER PATHWAY •
                           Likelihood of Release:
                  Observed Release By Chemical Analysis

               Comparable sampling and analytical procedures
               Collect most downstream samples first
               Collect aqueous samples before sediment samples at same
               location
        SI Guidance, section 4.6
OH* 16
                  Sample to Test Suspected Release
                                                ppc i    Source
                                                                 OKI
   •17
Surface Water Pathway
page 8-10
                                                                         10/94

-------
                            SURFACE WATER PATHWAY •
                                     Targets

            Sampling considerations for actual contamination
               • Must establish observed release first
               • Can infer contamination between "hits"
                - No need to sample each target
                - Can sample adjacent to or beyond (downstream of) target
                  locations
               • Sample for human health considerations, regardless of score
                - Always sample nearest drinking water intake if contamination is
                  suspected
         SI Guidance, section 4.6
      OH* 18
                       Targets: Inferring Contamination
                          Souret

                                                                      OH* 19
10/94
Surfra WtterPtthway
          page 8-11

-------
                         • SURFACE WATER PATHWAY
               Landfill
                   Key
                           Inferring Contamination
                                   Wetland
                          Bald eagle
                          habitat
         Flow direction

        Intermittent stream
                                                                    OH'20
Surface Water Pathway
page 8-12
                                                                           10/94

-------
                           SURFACE WATER PATHWAY
                       Targets: Drinking Water Threat

           To demonstrate actual contamination:
              • Sample types
               - Aqueous
               - Sediment
               - Sessile benthic
              • Collect samples at or downstream of target (intake)
              • Compare analytical results to benchmarks
              • Only aqueous samples can be used to score Level I targets
              • Level II can be established with any sample type
        SI Guidance, section 4.6
     OH* 21
                          Surface Water Benchmarks
SW Threat
Drinking water
Environmental
Human food
chain
Benchmark
MCL
MCLG
Screening concentrations
AWQC
AALAC
FDAAL
Screening concentrations
Sample Type
Aqueous
Aqueous
Tissue
        SI Guidance, section 4.6
      OH* 22
10/94
Surface Water Pathway
          page 8-13

-------
                          SURFACE WATER PATHWAY
                           Actual Contamination?
                          Level of Contamination?
                                           Key
                                           PPE
                                           Sample location   SW
                Drinking
                water
                intake
                                         15-mile	
                                         target distance limit
Sample
SW1
SW2
SW3
Result
Nondetect
100ppb
SOppb
Benchmark

10ppb

                                                                  OH* 23
Surface Wafer Pathway
page 8-14
                                                                          10/94

-------
                           SURFACE WATER PATHWAY
                     Targets:  Human Food Chain Threat

           Demonstrate actual contamination
              • Only attempt if this threat is essential to site score
              • Use sediment samples (not organisms)
              • Tissue sampling is expanded SI activity
              • If fishery is closed for fishing, surface water sample can be used
               to establish threat
              • Collect multiple samples
                                                                   OH* 24
                     Targets:  Human Food Chain Threat

           Sampling considerations for actual contamination
              • Observed release at target + bioaccumulation potential factor
                value (BCFV) considerations
              • Sediment, aqueous, and effluent samples - require substance
                within BCFV > 500
              • Tissue samples - no BCFV requirement
                                                                    OH* 25
10/94
                                                                        page 8-15

-------
                        • SURFACE WATER PATHWAY •
                         Actual Contamination?
Sample
SW1
SW2
SW3
SW4
Arsenic
2
175
190
80
                                           Key
                                           PPE
                                           Sample location

                                           Flow
                                                                 OH* 26
Surface Wator Pathway
page 8-16
                                                                        10/94

-------
                           SURFACE WATER PATHWAY
                        Targets: Environmental Threat

           Determine actual contamination
              • Only aqueous samples can be used to score Level I contamination
              • Collect at or downstream of sensitive environment
              • For wetlands
                - Sample near PPE
                - Two samples from wetland (at least 0:1 miles from PPE into
                 surface water)
              • Collect unfiltered surface water
                       Sensitive environments for this pathway
                     are found in PA table 5 in the PA scoresheets
        SI Guidance, section 4.6                                           OH • 27
        Notes:
10/94                                                           Surface Water Pathway
                                                                         page 8-17

-------
           PA TABLE 5:  SURFACE WATER AND AIR  PATHWAY SENSITIVE  ENVIRONMENTS VALUES
     Stnsftivt Environment
                                                                                                            Assigned Valui
     Critical habitat tor Federally designated endangered or threetened special
     Marine Sanctuary
     National Park
     Designated FedereJ Wildarnan Araa
     Ecologically important areai identified under lha Coastal Zone Wildgrnaii Act
     Sensitive Areis identified undar lha Nauonal Estuary Program or Naar Coanal Watar Program ol tha Clean Watar Act
     Critical Araai Identified undar tha Claan Lakai Program ol tha Claan Warn Act  (suberies in lakes or antira smell lakat)
     National Monument (air pathway only)
     National Saaihore Racraabon Araa
     National Lakeshore Recreation Araa
                                         100
     Habitat known to be used by Federally deiignated or proposed indangered or threatened species
     National Praiarva
     National or State Wildlife Refuge
     Unit of Coastal Barrier Raaourcai System
     Federal land daaignated  for tha protection of natural ecosystems
     Administratively Proposed Federal Wilderness Area
     Spawning areas critical for the maintenance of fish/shellfish species within a river system, bay, or oitviary
     Migratory pathways  and feeding areas critical for tha maintenance of anadromous fish species in  e river system
     Terrestrial areas utilized (or breeding by large or dense aggregations of vertebrate animals (air pathway) or
          lami-equatic foragers (surface water pathway)
     National river reach designated as Recreational
                                        75
     Habitat known to be used by Slate designated endangered or threatened species
     Hebilat known to be used by a species under review aa to its Federal endangered or threatened status
     Coastal Barner (parrieJIy developed)
     Federally designated Scenic  or Wild River
                                         SO
     State land designated lor wildlife or game management
     Slate designated Scenic or Wild River
     State designated Natural Araa
     Particular areas, relatively small in size, important to maintenance of unique biotic communities
                                                                                                                  25
     Slat» designated arees lor protection/maintenance ol aoualic life under the Claan Water Act
     Wetlands
             Sea PA Table 8 (Surface Water Pathway!
                               or
            	  PA Table 9 (Air Pathway)
                                        PA TABLE 6:   SURFACE WATER PATHWAY
                                              WETLANDS  FRONTAGE VALUES
                                       Total Length of Wetlands
Assigned Value
                                      Less than O.V mile
                                      0.1 to 1 mile
                                      Greater than 1 to 2 miles
                                      Greater than 2 to 3 miles
                                      Greater than 3 to 4 miles
                                      Greater than 4 to 8 miles
                                      Greeter than 8 to 1 2 miles
                                      Greater than 1 2  to  16 miles
                                      Greater than 18  to  20 mules
                                      Greater than 20  miles
       0
       25
       50
       75
       IOO
       ISO
       250
       350
       450
       500
Surface Water Pathway
page 8-18
                                                               A-31

-------
                            SURFACE WATER PATHWAY •
                              Focused SI Strategy

           If PA hypothesized release to surface water and targets are
           present:
              • Sample locations at or near PPE and background
              • Sample effluent discharge (no background needed)
              • Sample all drinking water intakes suspected to be exposed
                (primary targets)
              • If multiple primary target threats are present, collect sediment
                samples
        SI Guidance, section 4.6.1                                           OH • 28
                              Focused SI Strategy

            To establish background
              • Background and release/target samples must be same sample
                type
              • Background samples include:
                - Sediments upstream of PPE (and out of site influence)
                - Aqueous samples upstream of PPE (only if drinking water
                  targets are threatened)
         SI Guidance, section 4.6.1                                          OH • 29
10/94                                                            Surface Water Pathway
                                                                          page 8-19

-------
                            SURFACE WATER PATHWAY
                       Expanded and Single SI Strategy

              • Determine whether aqueous samples are needed to demonstrate
               a release
              • Collect surface water samples at targets that were not sampled
               earlier
              • Sample to expand fishery and wetland boundaries if these are
               important
        SI Guidance, section 4.6.2                                          OH • 30
         Notes:
Surface Water Pathway                                                           10/94
page 8-20

-------
        TABLE 4-10: SURFACE WATER SAMPLES TO SUPPORT A RELEASE AND TARGET
                                   CONTAMINATION
HRS Factors
Observed release
Level I drinking water
Level II drinking water
Level I sensitive
environments
Level II sensitive
environments
Level I fisheries
Level II fisheries
Sediment1
Yes
No
Yes
No
Yes
No
Yes3
Aqueous
Yes
Yes
Yes
Yes
Yes
No
Yes3
Effluent1
Yes
No
Yes
No
Yes
No
Yes3
Sessile
Benthic
Organisms
Yes
No
Yes
No
Yes
Yes'
Yes5
Non-sessile
Dentine
Organisms
No
No
No
No
No
Yes3-4
No
Finfish,
Amphibians,
and Reptiles
No
No
No
No
No
Yes3'4
No
1 No benchmarks available; evaluate as Level II contamination.
1 Does not require comparison to background to document a release.
3 Sample only tissues of edible species to evaluate human food chain level of contamination.
4 Can be used to score Level I targets, but not an observed release; must be collected within boundaries of
surface water contamination.
3 Targets can be evaluated if hazardous substance has a bioaccumulation factor value of 500 or greater.
   Guidance for Performing Site Inspections Under CERCLA, USEPA, 7992
4/94
Surface Water Pathway
           page 8-21

-------
                            SURFACE WATER PATHWAY
                      Surface Water Sampling Strategies

                      • SI Guidance, Table 4-11, Surface Water Sampling
                       Strategies, presents focused, expanded, and single SI
                       sampling criteria and strategies
                      • Prior to sampling, carefully plot sample locations using
                       information gathered during the site reconnaissance and
                       the nonsampling investigation
                      • Photodocument sample locations to aid in data
                       evaluation and to resample locations if necessary
         SI Guidance, section 4.6.3                                           OH • 31

                       	       J
         Notes:
Su/ftc« Mfeter Prtftway                                                             1Q/94
page 8-22

-------
                 TABLE 4-11: SURFACE WATER SAMPLING STRATEGIES
CRITERION
Primary
objectives
Data quality
Average
number of
samples
Types of
activities
Background
samples
Attribution
samples
QA/QC
samples
FOCUSED SI
To test hypotheses regarding a suspected
release and primary targets
When possible, sample at or beyond targets
to test release hypotheses
Less rigorous (e.g, DUC-II) to rigorous
(e.g., DUC-I)
0 to 6 depending on site hypotheses and
number of surface water targets to sample
Sample easily accessible surface water
locations
Sample sediments at or beyond targets most
likely to indicate contamination
1 background per 3 release samples
May rely on published -data
Limited to testing release hypotheses
Enhance confidence in sample results
EXPANDED SI AND SINGLE SI
To document a release based on HRS
requirements
To document targets exposed to actual
contamination and determine levels of
exposure
Rigorous (e.g., DUC-I)
Q to 14 based on HRS documentation
requirements
Resample surface water locations if
previous data did not document a release
or targets exposed to actual contamination
Sample surface water targets not yet
sampled, particularly sensitive
environments and wetlands
Collect multiple aqueous samples from
drinking water intakes where hazardous
substance concentrations are likely to be
near surface water benchmarks
2 background per 3 release samples
Should not rely on published data
Those necessary to attribute a portion of a
release to the site
Those necessary to obtain precise and
accurate data within the SI scope
Guidance for Performing Site Inspections Under CERCLA, USEPA, 1992
                                                                        Surface Water Pathway
                                                                                    page 8-23

-------
                             SURFACE WATER PATHWAY
                                   CASE STUDY

        EXAMPLE OF SURFACE WATER SAMPLING STRATEGY: FOCUSED SI

Returning to the Lakefield Farm Site example, the site description now includes the Apsley
River, a moderate-to-large water body (streamflow 900 cfs) approximately 200 feet north of the
surface impoundment (see Lakefield Farm Site Sketch 3).  A recreational fishery is located
within the river, and a 10-acre wetland lies 1 mile downstream from the PPE. An unnamed
creek flows into the Apsley River about 750 feet upstream of the PPE, and an outfall to this
creek is 1 mile upstream of this confluence.  During the PA, the investigator suspected a
release to the Apsley River from the Lakefield Farm and a release to ground water.

Because of significant threats to both ground water and surface water and because attribution
is a problem, a focused SI is planned with an expanded SI to be performed if necessary.
Focused SI sampling will test whether ground water and surface water targets are exposed to
contamination.
      SED-l
                            Lakefield Farm Site Sketch 3
                                                    GW-2
                                                                       SED-7
                                             -$•&
                                              GW-3
                                               /Wetiind
                                                        LAKGFIELD
                                                        FARM SITE
                                           SS-1
                                          <*±*
                                            GW-4
KEY

Surface waler sediment sample

Surface waler aqueous sample

Source sample

Drinking water well

Irrigation well

Pijlicry
                                                   GKEEN A CUES
                                                    SUBDIVISION
 Surface Water Pathway
 page 8-24
                                       Municipal Well
                                                  GW-7
                                                                   — N —
                                                                  NOT TO SCALE
                                                                       10/94

-------
                       SURFACE WATER PATHWAY
    SURFACE AND GROUND WATER SAMPLING STRATEGY FOR EXAMPLE SITE:
                             FOCUSED SI

Sample*

Municipal wM (oW-r J


Domestic wale
(GW-3 through GW-o)

Background for ground
water

Surface water target
locations
Background for surface
wmtw(SW-1,SED-1)

Sourcaa
(SD-1, SL-1, SS-1, SS-2)

Quality control
(Q-1 through Q-4)
(not shown)

Approach
_ 1 .... . .

tiaatiiiaiit^ aiiinpJa to documant
aubatancaa, and datarmina laval
of contamination
Sampia naaraat domaatic waUa

IAN flM 1 HI IMI^JT 1
Sample drinking water aquifer;
Ivmt numbar of background
aamplaa


contamination is prasant in ths
fishary (SEO-4) or wetland
(SED-S, SED-6)
Umtt numbar of background
•amplas
• .* i
Identify hazaiuous substances
present at the site through
composite aamplu
Monitor collection and
decontamination procedures; one
rinsate for ground water
equipment, one nnaate for surface
water equipment, one trip and one
field blank

Rationale
** * ' ' * • 	 i •

GoniattMnaoon la cinicaj to prooacnng
decision
DatarnwnQ oomaate WN
coniafnafiauon • uiucai n pfovacung
puoac naann ana v> ma aiia acraanaTiy
daymen
Sampia to datanrvna raiativa
oof tcanu auor ta of nazarooua
aubatancaa in ambiant conditiona


•c/aanviQ daciaion
Sa/npla to datanrma lavaia of
i-, — -_— !-.,-» n - ^ ^ J-. »*•--. !-••
nazarooua auDavncaa
t L j
Do not aampla to ancraaaa hazardoua
waata quantity if amounts ant not doaa



nonaampang
Data Colaction

VVIHJ aqunar irem wncn wvi dmw,
varify population aarvad

Varify acMfar from which wala draw;
Vawwy popuuuun aarvao

Varify aquifar from which wala draw

\Jmrjtu aWiaiair Ih-LTataxrui s* laaarftavwi


Cdect information about background
— — --.-il— tn |-|»tina» ^**i± , Jt— — ^^Ji£>»^
aampai Demon, iimuong aacung,
flow, and phyaical charactanatica
(a.g.. aadimant grain aiza)

uocajn pnyacaj amanapna or
aunaca •mpounamani ami aaonuiia
mr^m raf /xruifarrunatmH mfJt tjaartfti
numbar of druma and took for dmrn
labala

10/94
Surface Water Pathway
        page 8-25

-------
        Section 9:
Soil Exposure Pathway
            Fence
    Breach
    in fence
         H     M
              200 feet
   s
   0)
                         o
                         9
             XYZ
          Corporation
Contaminated f
  Soil

-------
                             SOIL EXPOSURE PATHWAY
                             Soil Exposure Pathway

            Pathway score based on:
               • Likelihood that residential, school, or workplace properties are
                contaminated
               • Likelihood that residents, students, or workers are exposed to site
                contaminants
         SI Guidance, section 4.7
                                     OH»1
                             Soil Exposure Pathway:
                              MRS Considerations
                   Waste
               Characteristics
Likelihood of
 Exposure
         SI Guidance, section 4.7
                                                          Human
                                                        Population
                                                          Threat
Worker
Threat
                                                         Sensitive
                                                        Environment
                                                          Threat
                                      OH* 2
Soil Exposure Pathway
page 9-2
                                                                               10/94

-------
                          • SOIL EXPOSURE PATHWAY •
                             Review PA Information

           Determine whether a major pathway of concern is based on:
              • Resident individuals (onsite residents, students)
              • Workers
              • Terrestrial sensitive environments
         SI Guidance, section 4.7                                             OH • 3
                            Review PA Information

                       Identify number and location of primary targets
                       Identify areas of suspected surficial contamination
                       Identify property boundaries
                       Has contamination already been demonstrated?
         SI Guidance, section 4.7                                             OH • 4
10/94                                                             Soil Exposure Ptthway
                                                                            page 9-3

-------
                           SOIL EXPOSURE PATHWAY
                    Soil Exposure Pathway Investigation
                         Complete SI data summary soil
                        section using available information
                  See SI Guidance, Appendix B, "SI Data Summary"
        SI Guidance, section 4.7
OH* 5
                       Most Important Analytical Data

                        Establishing observed contamination
                        Establishing level of contamination
        $1 Guidance, section 4.7
                                                                    OH* 6
So//Exposure Pathway
page
                                                                           10/94

-------
                             SOIL EXPOSURE PATHWAY
                     Establishing Observed Contamination

                Must use analytical evidence
                Should demonstrate:
                - Attribution
                - Contamination present at significant levels
                Need to collect two soil samples
                - Background
                - Area of contamination
                If observed contamination cannot be established, do not evaluate
                soil pathway
         SI Guidance, section 4.7                                            OH • 7
                Sampling Criteria for Observed Contamination

                Must meet criteria for observed contamination (similar to
                observed release for migration pathways), and samples must be
                collected within 2 feet of surface
                Cannot collect sample beneath impenetrable cover
                Can infer contamination within a source, not between sources
                For all sources except soil, one observed contamination sample
                demonstrates an area of surficial contamination for entire source
         SI Guidance, section 4.7                                             OH • 8
10/94                                                             Soil Exposure Pathway
                                                                            page 9-5

-------
                            SOIL EXPOSURE PATHWAY
               Sample for Observed Contamination (Sources)
                      Landfill
                Former drum
                Storage area
                           Area of suspected
                           contamination
      SI Guidance, section 4.7
 OH-9
                           Sampling Considerations

           Sample to identify targets exposed to surficial contamination
              • Resident individuals most heavily weighted
              • Workers
              • Terrestrial sensitive environment
              • Resources

           Sample in direction of targets only
              • Do not sample to delineate total extent of surficial contamination
      SI Guidance, section 4.7
OH«10
So/7 Exposure Pathway
page 9-6
                                                                              4/94

-------
                           • SOIL EXPOSURE PATHWAY
                             Target Considerations

            Resident individuals and workers
               • Demonstrate contamination on property and within 200 feet of
                 residence, school, or workplace

            Sensitive environments and resources
               • Demonstrate contamination within boundary
                                                                      OH«11
                    Sample to Define Resident Individuals
                              Areas of vegetation/
                              suspected soil contamination
                                                                     OH* 12
4/94
Soil Exposure Pathway
           page 9-7

-------
                            SOIL EXPOSURE PATHWAY
                 Estimating Areas of Observed Contamination

                Sample to identify resident population threat targets
                Three soil samples (minimum) needed
                Two soil samples for critical targets that lie along a line
                One nonsoil source sample can designate an entire source as
                area of observed  contamination
         SI Guidance, section 4.7
              OH* 13
                        Area of Inferred Contamination

                Established between two points of observed contamination
                                      Source
                   0'  100' 200'
         SI Guidance, section 4.7
                                   (aerial view)
House
Property boundary
Soil sample
               OH* 14
Soil Exposure Pathway
page 9-8
                                                                              4/94

-------
                            SOIL EXPOSURE PATHWAY
                            Inferring Contamination
                                                                     OH* 15
                      Evaluating Level of Contamination

              Analytical results are compared with benchmarks
              Populations associated with areas of inferred contamination can
              only be evaluated as Level II resident threat targets
         SI Guidance, section 4.7
      OH-16
4/94
Soil Exposure Pathway
           page 9-9

-------
                           SOIL EXPOSURE PATHWAY
                          Levels of Contamination
                                = Soil samples
                                 (all exceed ng benchmark)
                                                                   OH»17
                     Additional Sampling Considerations

           • Soil samples collected for comparison should be similar
              • Soil type
              • Same soil horizon
              • Mineralogy
              • Composition
           • For background, observed contamination, and metals analysis
            samples, need similar:
              • Texture
              • Color
              • Grain size
           • For MRS purposes, grab samples are preferred
        SI Guidance, section 4.7                                          OH • 18
Soil Exposure Pathway
page 9-10
                                                                           4/94

-------
                             SOIL EXPOSURE PATHWAY
                            Establishing Background

            Background samples should:
               • Represent uncontaminated conditions
               • Be collected from undisturbed areas
               • Not be collected from drainage channels
               • Be collected within 1-3 days of release sample (can use results
                from nearby sites for focused SI)
         SI Guidance, section 4.7                                            OH • 19
                              Focused SI Strategy

                Review PA hypotheses concerning suspected observed surficial
                contamination and exposed targets
                Establish areas of observed contamination
                Target resident individual exposures
                Can use inferred contamination areas
                Less rigorous data quality
      SI Guidance, section 4.7.1                                              OH • 20
4/94                                                              Soil Exposure Pathwty
                                                                            page 9-11

-------
                            SOIL EXPOSURE PATHWAY
                        Expanded and Single SI Strategy

               • Focus on documentation of target exposure
               • Sample locations not sampled during earlier investigations
               • Establish and document background
               • Rigorous quality control
         SI Guidance, section 4.7.1
OH* 21
                             Soil Sampling Strategy
                    SI Guidance, Table 4-14, Soil Sampling Strategies,
                    compares criteria and activities associated with focused,
                    expanded, and single Sis
         SI Guidance, section 4.7.1
OH* 22
Soil Exposure Pathway
page 9-12
                                                                               4/94

-------
                       TABLE 4-14:  SOIL SAMPLING STRATEGIES
CRITERIA
Primary
objectives
Data quality
Average
number of
samples
Types of
activities
Background
samples
Attribution
samples
QA/QC
samples
FOCUSED SI
To test hypotheses regarding suspected
observed surficial contamination and
targets exposed to actual contamination
Less rigorous (DUC-II) to rigorous
(DUC-I); depends on objectives
0 to 10 depending on site hypotheses and
resident population to investigate
Sample source and target areas indicating
possible surficial contamination, exposed
or within 2 feet of surface
Limited
May not be necessary for some organics
May rely on published data
Limited
As approved by Regional guidelines
EXPANDED SI AND SINGLE SI
To document target exposure to hazardous
substances related to site sources
Rigorous (DUC-I); depends on objectives
0 to 20 based on documentation requirements
and number of sources and targets
Resample locations if previous data did not
demonstrate areas of observed contamination or
targets exposed to actual contamination
Sample other resident target properties not yet
sampled
Collect multiple samples from properties where
hazardous substance concentrations are likely to
be near benchmarks
As many as necessary; research natural soil
concentrations as well as development history in
the area to select critical background sample
locations; use aerial photographs.
Those necessary to attribute substances to the
site being evaluated
Minimum 1 split and 1 blank or per Regional
guidelines
Guidance for Performing Site Inspections Under CERCLA, USEPA, 1992
                                                                        Soil Exposure Pathway
                                                                                   page 9-13

-------
                              SOIL EXPOSURE PATHWAY
                                    CASE STUDY

               EXAMPLE OF SOIL SAMPLING STRATEGY: FOCUSED SI

The Carveth Landing site is a dump near a residential neighborhood and elementary school
(see Carveth Landing site sketch).  The PA reported that dumping occurred for an unknown
period of time and allegedly included paints, organic and inorganic substances, and construc-
tion debris. The area is devoid of vegetation.  Sources at the site include several piles of 5-
gallon containers and two poorly defined areas of stained soil.  Pigeon River, which flows at
1,600 cubic feet per second and is  located 400 feet east of the site, has flooded twice in the
past 7 years. Commercial and recreational oyster beds are downstream of two PPEs to sur-
face water. The PA concluded that flooding may have carried hazardous substances into the
surface water and onto adjacent school and residential properties. Hazardous substances
associated with the site are not known, but could involve metals typically found in paints.
            A XS-3
                             Carveth Landing Site Sketch
                        A XS-4          ^ XS-5
            Key
          • Source simple
          A Soil sample

          Q Sediment junplc
         f* Fishery

          X XS = Expanded SI soil jtmple
A SS-7
                                         XS-10
                  AXS-II


                     A SS-10

                       A SS-9
              SCHOOL
 Soil Exposure Pathway
 page 9-14
              :-82A  Li  XS-14A/X
                                       XS-15A
                                                                                  4/94

-------
                       SOIL EXPOSURE PATHWAY
      SOIL AND SURFACE WATER SAMPLING STRATEGY FOR EXAMPLE SITE
                             FOCUSED SI
Sample*
Surface water location*
(ScD-3, SEEM)

B 'J 41 1 'I 1


Background soil
(SS-7, SS-8)
Background eurface
water (SED-1, SED-2)
Source*
(SS-1 through SS-6)
Quality control
(Q-1 through Q-3)
Approach
Sample aedimenti to
demonstrate a release;
determine if contamination is
present and level of
contaVninfltion
«* -1 h. J frn & rK

SS-1 2, SS-1 3) and the school
yard (SS-9, SS-10) are exposed
to surfiaaJ contamination
Limited
Collect sediment sample*
upstream of PPEs; ensure
sample* are beyond tidal
influence of hazardous
substance migration
Identify hazardous substance
present at the site; sample to
test hypothesis of surficial
contamination
Monitor sample collection and
decontamination procedure*;
two rinsatee and one trip blank
Rationale
Investigate release to surface
water and determine if fishery ia
exposed to actual comammanon
1 K t 1 ti h»


Sample to determine relative level*
of hazardous substance* under
ambient conditions and to better
define effect* of flooding at site
Sample to determine relative levele
of hazardous substances under
ambient conditione
Do not sample to increase
hapirriniM wast* quantity because
amounts are not dose to HWQ
factor value breakpoints

Nonsamping
Data C election
Document use of river for fishing;
estimate annual commercial food
cham production for oyster*


students attending school
If available, obtain historical
aerial photograph* and FEMA
map*; research natural
background levele of metaia
Reaearch other potential source*
of hazardous substance*
Estimate physical dimension* of
stained soil; count paint pate and
look for drum label*

4/94
So// Exposure Pathway
         page 9-15

-------
                                 SOIL EXPOSURE PATHWAY
                                       CASE STUDY

                 EXAMPLE OF SOIL SAMPLING STRATEGY: EXPANDED SI

 An expanded SI was performed at the Carveth Landing site using the following sampling
 strategy.
                     SOIL SAMPLING STRATEGY FOR EXAMPLE SITE
                                       EXPANDED SI
         Samples
        Approach
        Rationale
    Nonsampling
    Data Collection
Resident samples
(XS-7,XS-8,XS-9,XS-11
through XS-17)
Sample to document resident
targets and levels of actual
contamination
To establish observed
contamination on residential
and school properties, target
samples must be 3 or more
times the ambient
background levels
Determine number of
residents, property
boundaries, and number
of students
Background
(XS-3 through XS-6, XS-10)
Sample areas less influenced
by site; document
contamination attributable to
site
Show that target
contamination is attributable
to the site, rather than other
potential sources of lead;
ensure sufficient background
samples for MRS
documentation
Quality control
(Q-1 through Q-6)
Monitor sample collection and
decontamination procedures;
transport and handling
procedures; two equipment
rinsates, two duplicates, one
field blank, one replicate
Ensure sufficient QA/QC
samples for HRS
documentation
  Soil Exposure Pathway
  page 9-16
                                                                                        4/94

-------
                                Section 10:
                               Air Pathway
   Threat
Potential sources
of a release to air
           Fire
     Burn operation (odors,
      gases, participates)
                                                                         Contaminants may
                                                                        settle on buildings or
                                                                          settle onto soils
                                   Mine tailings
                                       pile
                                    Sensitive Environment
                                     (e.g., habitat park, or
                                      recreation area)
                                                    Dry and dusty
                                                 conditions may cause
                                                   particulates to be
                                                    blown offsite
       Waste water
         lagoon
   May release
vapors/gases that are
 detected by nearby
 residents/workers
Contaminated
    soils

-------
                                  • AIR PATHWAY •
                             Air Pathway Evaluation

            Pathway score based on:
               • Likelihood that airborne contaminants are migrating from site
               • Likelihood of detecting contaminants at human and sensitive
                 environment targets
         SI Guidance, section 4.8                                              OH • 1
V
                              Review PA Information

                 Was air pathway significant to preliminary score?
                 Identify sources (source areas)
                 Identify primary targets and primary target populations
                 Identify most dispersible substances
         SI Guidance, section 4.8                                              OH • 2
A/rPttfiway                                                                        4/94
page 10-2

-------
                                • AIR PATHWAY •
                         Air Pathway Investigation
              Complete the SI data summary air section using available
              information.

              This information may help determine whether to evaluate the
              pathway.
                           See SI Guidance, Appendix B,
                      SI Data Summary, pages B-19 through B-21
      SI Guidance, appendix B
OH* 3
                      When Is Air Sampling Appropriate?

            Is air the only significant pathway?
               • Typically expanded or single SI activity

            Evaluating air pathway during focused SI
               • Generally sample air only if immediate human health threat exists
               • Monitor to better assess release potential
         SI Guidance, section 4.8
OH* 4
4/94
  Air Pathway
    page 10-3

-------
                                 AIR PATHWAY
                      Air Pathway: MRS Considerations
Waste
Characteristics


Likelihood of
Exposure
        SI Guidance, section 4.8
                                                          Targets
                                                         Likelihood
                                                        of Detection
OH* 5
                     Air Pathway:  Likelihood of Release

                       Depends on nature of source
                          • Chemical properties
                          • Thickness of cover

                       Affected by atmosphere
                          • Wind direction
                          • Temperature
         SI Guidance, section 4.8
OH* 6
Air Pathway
page 10-4
                                                                             4/94

-------
                                  AIR PATHWAY
                   Observed Release by Direct Observation

                Particulate emission seen entering atmosphere directly
                Use photographs to document emissions
                Need information supporting that emission material contains
                hazardous substance
                - Existing analytical data
                - Manifests
                - Soil or source samples
                Sample source to document direct observation
         SI Guidance, section 4.8
OH«7
                   Observed Release by Direct Observation
                                                  Residential area
                                                 Residential Area
                                                                       OH* 8
4/94
  Air Pathway
    page 10-5

-------
                                • AIR PATHWAY
                       Air Pathway: Observed Release

           Background and release samples should be similar
              • Collection and analysis
              • Same time frame

           Background sample locations should be outside influence of site
           to ensure attribution
                                                                    OH-9
V
r
                             Air Pathway:  Targets

                Do not need to sample air targets directly
                Observed release can demonstrate actual contamination of
                targets within the distance category
                                                                    OH* 10
AJr Pathway                                                                   4/94
page 10-6

-------
                                   AIR PATHWAY •
                                    Air Targets
                                                                        OH«11
                          Air Sampling Considerations

                 Sample targets within a 0.25-mile target distance limit
                 Conduct before or after other sampling activities (not during)
                 May require more than one sampling event
                 Should not be conducted near facilities discharging into air
                 Monitoring stations should be located near sources
         SI Guidance, section 4.8.3
OH* 12
4/94
   AlrPtthway
    page 10-7

-------
                                  AIR PATHWAY •
                              Focused SI Strategy

           Air sampling for CLP analysis should not be conducted during
           focused SI

           Ambient air screening may be appropriate
              • Health and safety
              • Release detection
         SI Guidance, section 4.8.1                                          OH • 13
              	J
                       Expanded and Single SI Strategy

                Single SI option is selected if air is only pathway of concern
                Conduct sampling:
                -  If air pathway is of concern
                -  If public health is threatened
                Minimum 12-hour sampling time to reduce variability
                Determine predominant wind direction
                Rigorous quality control
         SI Guidance, section 4.8.2                                          OH • 14
Air Pathway                                                                      4/94
page 10-8

-------
                               • AIR PATHWAY
                      Expanded and Single SI Strategy:
                          Establishing Background

                      Necessary at this stage
                      Upwind or cross-wind samples acceptable
                      Multiple samples preferred
         SI Guidance, section 4.8.2
OH-15
                          Establishing  Background
                                                                   OH* 16
4/94
   Air Pathway
    page 10-9

-------
                                    AIR PATHWAY
                                    CASE STUDY
                       EXAMPLE OF AIR SAMPLING STRATEGY
Vega Ore is a remote site near Smalltown where ore is processed for the extraction of lead,
zinc, and silver (see Vega Ore site sketch). The site has been operating since 1930, and
current activities are very limited. Waste sources include three tailings piles, a drum storage
area for acids, and an aboveground tank.

The nearest residence is 1,000 feet from a tailings pile.  Smalltown relies on drinking water
from an intake 3 miles away. A national park is located 900 feet from the site. A total of six
ranches within 0.25 miles of the site rely on bottled water and cisterns for drinking water.
Based on PA research, the significant threats posed by Vega Ore involve suspected migration
of hazardous substances through air that may impact people and sensitive environments.  No
ground water targets exist, and the nearest surface water body is more than 2 miles from the
site.

                                 Vega Ore Site Sketch
                                    Prevailing wind direction
                                      durlnj »lr jumpllnj
                                                                    NitioniJ Pirk
Air Pathway
page 10-10
                                                                            0.25 Mflc
                                                                           Targci DLSOUJCC
                                                                             Limit
                • Source Jvmpl

                * Ai/ junplc-s
                                                                                    4/94

-------
                              AIR PATHWAY
                AIR SAMPLING STRATEGY FOR EXAMPLE SITE
Sample*
Release and air target*
(A-4 through A-6)
Support for release and
air targes (A-7, A-8)
Background
(A-1 through A-3)
Source*
(SS-1 through SS-S)
Quality control
(Q-1 through Q-4)
(not shown)
Approach
Sample to test if contamination is
present and determine level of actual
contamination
Monitor wind •peed, direction, end
other atmospheric conditions
Sample to test if other sources of air
contamination exist in the site
vicinity, or if wind direction changes
during the sampling event; establish
cross-wind sample stations
Sample to collect background levels
of ambient air concentrations
Sample to determine background soil
levels
Identify hazardous substances
present at the site through surfictal
soil samples and tailing samples
Monitor sample collection and
decontamination procedures; 2 trip
blanks and 2 duplicates
Rationale
Determining whether the 0. 25-mile
target distance category ie exposed
to actual air contamination is vital to
investigating the fnfmTi health and
the screening and listing decisions
Support determining whether the
0.25-mile target distance category is
exposed to actual contamination
Sample to determine relative levels of
perticulsts hazardous substances in
ambient conditions
Ensure sufficient background
samples for listing purposes
Do not sample to Increase hazardous
waste quantity (amounts are not
dose to HWQ factor value
breakpoints)
Ensure sufficient QA/QC samples for
listing purposes
Nonsampiing
Data Collection
Determine population of SmaMown
lying within the 0.25-mile target
distance category from arts sources
Determine number of workers at Vega
Ore
Dtrtenraiti bound&viiM of ntroonM
perk

Identify other sources of pertfcuMa
•fTwmons «n &VM
WOMCl OMCnpuVV sfllUfflllUOn TOT 81
bflckQround Mfnpw locations

UDtBsTi pnywcu oUTwntiont of TBRKS,
drum, and tailings pita, and
otifTiiti ATM of oontevrvmtod soij
verify number of drum* and look for
drumtabs^s

4/84
Air Pathway
 page 10-11

-------
Section 11
 Radiation

-------
                                    RADIATION
                                    Definitions
         1. Radioactive Substance — Solid, liquid, or gas containing atoms
           of a single radionuclide or multiple radionuclides.

         2. Radionuclide/radioisotope— Isotope of an element exhibiting
           radioactivity. For MRS purposes, "radionuclide" and
           "radioisotope" are used synonymously.

         3. Radioactivity — Property of those isotopes of elements that
           exhibit radioactive decay and emit radiation.

         4. Radiation— Particles (alpha, beta, neutrons) or photons (X- and
           gamma-rays) emitted by radionuclides.
         MRS Final Rule, section 1. 1, page 51586
OH • 1
                          Radioactive Substances Are:

                Hazardous substances under CERCLA and should be considered
                in MRS scoring
                Treated as additional wastes with special properties under the
                MRS

                      Special analytical data requirements apply
        MRS Final Rule, section 7.0, page 51663
OH* 2
RatBatton
page 11-2
                                                                                10/94

-------
                                    RADIATION
                         Three Groups of Radionuclides

               1.  Naturally occuring or ubiquitous in the environment
               2.  Man-made radionuclides not ubiquitous in the environment
                  (elements beyond atomic number 92: uranium)
               3.  Gamma radiation
         HRS Final Rule, section 7.1.1, page 51663;
         SI Guidance, section 4.9.4, page 89
OH* 3
                              Radiation Measurement

         Radiation is measured in activity units (curies)

         Curie (Ci):  Measure used to quantify radioactivity. One curie equals
                    37 billion nuclear transformations per second and one
                    picocurie (pCi) equals 10~12 Ci.
Media
Soil
Ground/surface
water
Air
Unit Measurement
pCi/kg
pCi/L
pCi/m3
         HRS Final Rule, section 7.1.1, page 51663
OH* 4
10/94
    Radiation
    page 11-3

-------
                                  • RADIATION •
                              CERCLA Exclusions

         Section 101(22) of CERCLA excludes a limited category of
         radioactive materials, making them ineligible for CERCLA response
         ortheNPL

         1.  Excludes releases of source uranium or thorium..., by-product or
            material  made radioactive by exposure to radiation from the use
            or production of special nuclear material (plutonium, ^U,
            enriched ^U, ^U) or any material that the NRC determines to
            be special nuclear material subject to section 170 of the AEC
            Act.

         2.  Any release of source, by-products, or special nuclear material
            from any processing site specifically designated under the
            Uranium Mill Tailings Radiation Control Act of 1978.


         MRS Guidance, page 19                                             OH • 5
                       Potential Radioactive Waste Sites

                Pose special hazards for field investigators (gamma radiation)
                Less than 2 percent of CERCLIS sites involve radioactive
                materials
                Detailed investigations and information are handled by EPA's
                Office of Radiation Programs (ORP)
         PA Guidance, section 2.7, page 34                                      OH • 6
Radiation
page 11-4

-------
                                   • RADIATION
                 Facilities That Contain Radioactive Materials

                DOD/DOE research labs, contractors, and suppliers
                Public/private energy production and research labs
                Ore mining, milling, and processing industries
                Deep well injection sites
                Aircraft, submarine, and shipbuilding companies
                Businesses that manufacture, use, store, or dispose of
                radiopharmaceuticals
                Industrial radiography (X-rays)
         PA Guidance, section 2.7, page 34                                      OH • 7
                        Evidence of Radioactive Materials

               • Presence of drums and containers with radiation symbols
               • Permits, manifests, and records of radioactive materials
               • Above-background readings on a radiation meter

               (EPA action guideline:  readings > 1milliroentgen/hour for
               gamma radiation; evacuate area!)
         PA Guidance, section 2.7, page 34                                      OH • 8
10/94                                                                         Rtdlttlon
                                                                             page 11-5

-------
                                   • RADIATION •    =
                            Radiation Sampling* Goals
               • Identify radionuclides and activity concentrations in situ, both
                 onsite and offsite
               • Locate elevated sources of radioactivity and external radiation
                 exposure rates
               • Estimate areal extent of contamination and major migration
                 pathways
               • Confirm radiation releases
               • Determine site-specific background radioactivity and exposure
                 rates
               • Document Level I and Level II contamination
               • Support QA/QC requirements (samples require CLP SAS)
                      * After consultation with a health physicist

         SI Guidance, section 4.9.1, pages 86-88                                  OH • 9
        	J
               Factors That Are Evaluated Differently under MRS
                               in All Four Pathways
                       • Observed release
                       • Toxicity
                       • Persistance
                       • HWQ
               Refer to MRS Final Rule, section 7, for specific information
         MRS Final Rule, table 7-1, page 51663                                  OH • 10
Radiation                                                                         10/94
page 11-6

-------
                                     RADIATION •
                                Observed Release

                 Direct observation for each migration pathway except soil
                 Measured concentration in activity units in all four pathways
         SI Guidance, section 4.9.4, pages 89-90                                 OH • 11
                                Observed Release

            1. Observed release for naturally occurring radlonuclldes

               • Concentrations that exceed upper limit of regional background for
                 a specific nuclide and media type
               • Must be attributable to site

            2. Observed release for man-made radlonucllde without
               ubiquitous background concentrations In the environment

               • Measure concentrations that equal or exceed the SQL* for that
                 nuclide in a specific media
               • Must be attributable to site

               * If CLP-generated data, use CRQL in place of SQL;
                if non-CLP-generated data, use IDL in place of SQL

         SI Guidance, section 4.9.4, pages 89-90                                 OH • 12
10/94
                                                                             page 11-7

-------
                                    RADIATION •
                 Observed Release for Soil Exposure Pathway

              • Must be present at surface or covered by 2 feet or less of cover
                material
              • Exceeds the upper-limit value of the range of regional background
                concentration values for that specific radionuclide in that type of
                sample
              • Must be attributable to the site
              • Excludes gamma radiation
         SI Guidance, section 4.9.4, page 89;
         MRS Final Rule, section 7.1.1, page 51664                               OH • 13
                 For Observed Release with Gamma Radiation

                Concentration equals or exceeds 2 times the site-specific
                background gamma radiation exposure rate
                Must be attributable to the site
                Does not have to be within 2 feet of the surface
         MRS Final Rule, section 7.1.1, page S1664                              OH • 14
                                                                              10/94
page 11-8

-------
                                     RADIATION
                        Hazardous Waste Quantity (HWQ)

                 Use activity units (curies) to evaluate sources
                 Need source area and depth (volume in cubic yards or gallons)
                 Need net activity concentration of each nuclide (after subtracting
                 background concentration)
                 Evaluate radionuclide constituent quantity (tier A) or wastestream
                 quantity (tier B)
         SI Guidance, section 4.9.2, pages 88-89                                  OH • 15
                                         HWQ

         Tier A:  Based on activity content. Convert from curies to equivalent
                pounds of nonradioactive hazardous substances by
                multiplying the activity estimate or area of observed
                contamination by 1,000. Assign the product as a constituent
                quantity value.

         TierB:  Based on activity content. Estimate total volume (cubic
                yards or gallons); divide cubic yards by 0.55 and gallons by
                110 to obtain equivalent pounds of noradioactive hazardous
                substances. Assign resulting value as radionuclide quantity
                value.

         Select the higher value for HWQ
         MRS Final Rule, section 7.2.5.7, pages 51665-51666                        OH • 16
10/94                                                                          Racfiatfon
                                                                              page 11-9

-------
       Section 12:
Site Inspection Evaluation
      and Reporting
   WC x LR x T  =  ~
      82,500
Site Score =
            gw
    Narrative Report
    SI Scoresheets

-------
                           EVALUATION AND REPORTING
                            SI Evaluation:  Overview
                          Review and Validate Analytical Data
                          Identify Analytical Data for Scoring
                            Review Nonsampling Information
                                     Score Site
         SI Guidance, chapter 5
OH*1
                           SI Evaluation: Data Review

                Compile all data
                - Existing
                - New SI data
                Include sampling and nonsampling information
                Evaluate existing analytical data using procedures outlined in
                chapter 3 of the SI guidance
                Evaluate new analytical data against performance criteria in SI
                work plan
         SI Guidance, section 5.1
                                                                         OH* 2
Evaluation and Reporting
page 12-2
                                                                                4/94

-------
                           EVALUATION AND REPORTING
                          SI Evaluation:  Data Review

              • Review should be conducted by the site investigator and project
                chemist
              • SI Guidance, table 5-1, provides data review considerations
         SI Guidance, section 5.1                                             OH • 3
      Notes:
4/94                                                            Evaluation and Reporting
                                                                           page 12-3

-------
                              TABLE 5-1: DATA REVIEW CONSIDERATIONS
        D  Review data reports for transcription and typographical errors (e.g., 0.5 v. .05; ppb v. ppm)
        D  Determine if sampling protocols were appropriate
        D  Compare data against field and trip blanks to detect cross-contamination
        D  Compare field replicates samples
        D  Review laboratory QC (e.g., laboratory blanks, method standards, spike recovery, duplicates)
        D  Summarize detection limits for non-detectable results
        D  Review detection limits for positive but non-quantifiable data
        D  Review sampling program design for assessing media variability
        D  Review background concentrations to help identify site-specific contamination
        D  Delete unusable data, attach qualifiers to usable data, and explain limitations of qualified data
     Guidance for Performing Site Inspections Under CERCLA, USEPA, 1992
Evaluation and Reporting
page 12-4

-------
                          EVALUATION AND REPORTING
                       SI Evaluation:  Data Review
             Scope of data review reflects use requirements
             Problems with data packages should be resolved with laboratory
      SI Guidance, section 5.1                                               OH • 4
     	y
                    SI Evaluation:  Identify Data for Scoring

            MRS aspects that depend on analytical data
              • Observed releases
              • Observed contamination (soil pathway)
              • Targets exposed to actual contamination
              • Levels of target contamination
              • Hazardous waste quantity
            Can use CLP and non-CLP data deemed suitable for SI objectives
      SI Guidance, section 5.2                                               OH • 5
4/94                                                           Evaluation and Reporting
                                                                         page 12-5

-------
                           EVALUATION AND REPORTING
                       SI Evaluation: Identify Data for Scoring

               Criteria for establishing acceptable minimum data quality:
                  • Intended use of data
                  • Specific site hypothesis being tested
                  • Particular MRS factor being examined
                  • Levels of target contamination
                  • Hazardous waste quantity
         SI Guidance, section 5.2                                            OH • 6
                       SI Evaluation: Identify Data for Scoring

                   Determine usability of qualified data
                   Qualifiers are added to data during laboratory analysis or data
                   validation
         SI Guidance, section 5.2                                             OH • 7
Ev*Ju*tion»nd Reporting                                                            4/94
page 12-6

-------
                           EVALUATION AND REPORTING
                        Analytical Data Review Process
                        Non-GIF
                        Data
                               Contract
                              compliance
                               •crtanlng
 Quality aaaurad,
ligaly dafanaibla
                                                                        OH* 8
                    SI Evaluation:  Identify Data for Scoring

            Qualified Analytical Data
               •  Data with attached letter code or "flag" indicates QA/QC problems
                 or questions concerning chemical identity or concentration
               •  Flag assigned by analyzing laboratory or person validating data
                                                                        OH* 9
4/94
                    Evaluation and Reporting
                               page 12-7

-------
                          EVALUATION AND REPORTING
£
V
SI Evaluation: Identify Data for Scoring
xample of Qualifed Data
Samples 1234
Trichloroethylene 40J 160 120 30J
Tetrachloroethylene 25U 150J 100R 45
Phenol 330U 390 19.000J 490
Concentrations (ppb)
OH* 10

r
                    SI Evaluation: Identify Data for Scoring

           Common Qualifiers in CLP Data
              • J-flag: Concentrations are estimated; identification of hazardous
                substances certain
              • U-flag: Compound analyzed for but not detected
              • R-flag: QC indicates data are unusable
              • Specific meaning of a qualifier may vary
                                                                     OH* 11
Evaluation and Reporting
page 12-8
                                                                             4/94

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                          EVALUATION AND REPORTING •
                   SI Evaluation: Nonsampling Information


                      • Review SI data summary sheets
                      • Update with new information if needed
                       - Changes in site conditions (e.g., a removal)
                       - Changes in targets
                      • Assess quality of nonsampling information
                           SI Evaluation: Site Score

                    General Strategy
                Characterize sources
                Focus on significant pathways
         SI Guidance, section 5.3                                          OH • 12

        	J
         SI Guidance, section 5.4                                          OH • 13
4/94                                                          Evaluation and Reporting
                                                                        page 12-9

-------
                        EVALUATION AND REPORTING
                        SI Evaluation: Site Score

              SI worksheet
              PREscore software program
              MRS scoresheets
              Other evaluation tools developed by EPA regional or state offices
             See SI Guidance, Appendix C, Site Inspection Worksheets
        SI Guidance, section 5.4
                    OH* 14
                       SI Reporting Requirements
                 Narrative
                   Report
                                   ii
 Score
Sheets
                                                              OH* 15
Evaluation and Reporting
page 12-10
                                                                      4/94

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                         • EVALUATION AND REPORTING
                        SI Reporting:  Narrative Report

            Report should:
               • Describe history and nature of waste handling at site
               • Describe known hazardous substances
               • Describe pathways of concern
               • Identify and describe targets
               • Present SI analytical results
         SI Guidance, section 6.1                                            OH • 16
                                                      	     J
                         SI Reporting:  Narrative Report

                Can be letter report or stand-alone document
                Factual statements should be supported by references
                References not generally available should be attached
                Structure and format should follow format in Exhibit 6-1, SI
                Narrative Report Format
         SI Guidance, section 6.1                                           OH • 17
4/94                                                            Evaluation and Reporting
                                                                         page 12-11

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                            EXHIBIT 6-1: SI NARRATIVE REPORT FORMAT
    INTRODUCTION

      •   State that an SI was performed, the name of the agency performing it, and the authority under which it
         was conducted (e.g., CERCLA as amended by SARA, and EPA contract or cooperative agreement).

      •   State the site name, CERCLIS identification number, and location (street address, city, county, State,
         latitude/longitude coordinates).  If necessary, provide brief directions to  the site.

      •   State the purpose, scope, and objectives of the SI.

    SITE DESCRIPTION AND REGULATORY HISTORY

      •   Identify the type of site (e.g., plating facility, chemical plant, municipal  landfill), whether it is active or
         inactive, and years of operation. Describe its physical setting (e.g., topography, local land uses).
         Include the appropriate portion of a USGS 7.5-minute topographic map  locating the site and showing a
         1-mile radius. On the map, identify the surface water drainage route; nearest well, drinking water
         intake, and residence; and wetlands and other sensitive environments. Include a drafted sketch showing
         site layout, source areas, and features on and around the site.

      •   Briefly summarize dates and scope of previous investigations.

      •   Describe prior land use and past regulatory activities including the site's RCRA status, permits, permit
         violations, and inspections by  local, State, or Federal authorities. Discuss any citizen complaints.

    OPERATIONAL HISTORY AND WASTE CHARACTERISTICS

      •   Provide an operational  history of the site. Identify current and former owners and operators, and
         describe site activities.   Identify and describe wastes generated,  waste disposal practices, waste source
         areas, waste source containment, and waste quantities.  Indicate source areas on the site sketch.

      •   Discuss any previous sampling at the site; provide dates of sampling events and sample types.
         Summarize analytical results in a table. Include a site map of all previous sample locations.

      •   Discuss SI source sampling results. List in a table each waste source sample and summarize analytical
         results. Include a site  map of all waste source and pathway sample locations.

      •   Identify hazardous substances associated  with sources.

      •   Describe accessibility to source areas.

    GROUND WATER

      •   Describe the local geologic and hydrogeologic setting (e.g., stratigraphy, formations, aquifers,  karst
         features,  confining layers, depth and permeability to each aquifer).
   Guidance for Performing Site Inspections Under CERCLA, USEPA,  1992
Evaluation and Reporting
page 12-12

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                   EXHIBIT 6-1: SI NARRATIVE REPORT FORMAT (continued)
GROUND WATER (continued)

  •   Discuss ground water use within a 4-mile radius of the sources.  Identify the nearest private and
     municipal drinking water wells and state the distance from sources. Quantify drinking water
     populations served by wells within 4 miles, differentiating between private and municipal wells and
     specifying aquifers.  Identify any municipal wells that are part of a blended system; state number of
     wells, locations, pumping rates, and aquifer from which water is drawn.  Identify wells in karst aquifers.

  •   Identify designated wellhead protection areas (WHPA) and specify location.

  •   Discuss any previous ground water sampling results; provide dates of sampling events and the depths
     and names of sampled aquifers.

  •   List in a table each well or spring  sampled during the SI, provide the depth from which  it draws
     drinking water and the screened interval, quantify the population associated with it, and identify its
     distance from site sources.  Discuss SI ground water sampling results.  List in a table each sample and
     summarize analytical results.  Include a site map of sample locations.  Identify drinking  water wells
     exposed to hazardous substances and quantify the drinking water populations served by each.

SURFACE WATER

  •   Describe the local hydrologic setting, including site location with respect to floodplains,  and the
     overland and in-water segments of the surface water migration path. State the distance from the site to
     the probable point of entry (PPE) into surface water.  Identify the water bodies within the in-water
     segment, and state the length of reach and flow or  depth characteristics of each; describe tidal influence.
     Include a drafted sketch of the surface water migration path.  Describe upgradient drainage areas, onsite
     drainage (including storm drains, ditches, culverts,  etc.),  facility discharges into surface water, permits,
     and historical information, including floods, fish kills, fishery closures, and other events.

  •   Indicate whether  surface water within the target distance limit supplies drinking water. Identify the
     location and state the distance from the PPE to each drinking water intake. Quantify the drinking water
     population served by surface water and identify blended systems.

  •   Indicate whether  surface water within the target distance limit contains fisheries.  Identify and state the
     distance from the PPE to each fishery; briefly characterize each fishery.

  •  Indicate whether sensitive environments are present within or adjacent to the in-water segment.  Identify
     and state the distance from the PPE  to each sensitive environment. Describe each sensitive environment
     and state the frontage length  of wetlands on surface water.

  •  Discuss any previous surface water sampling results, dates, locations,  and types of samples.

  •  Discuss SI surface water sampling results.  List in a table each sample and  summarize analytical results.
     Identify surface water intakes exposed to hazardous substances and quantify the drinking water
     .populations  served by each.  Identify fisheries exposed to hazardous substances and quantify the food
     chain population associated with  each.  Identify sensitive environments and wetlands exposed to
     hazardous substances; quantify the frontage of exposed wetlands.
Guidance for Performing Site Inspections Under CERCLA, USEPA,  1992
                                                                                   Evaluation and Reporting
                                                                                                   page 12-13

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                      EXHIBIT 6-1: SI NARRATIVE REPORT FORMAT (continued)
    SOIL EXPOSURE

     •   State the number of workefs on properties with site-related contamination.

     •   State the number of people who live on properties with site-related contamination and within 200 feet
         of an area of observed contamination.  Slate the hazardous substance concentration and compare to
      ,  health based benchmarks.

     •   Identify schools and day care facilities within 200 feet from an area of observed contamination on the
         school property and state the number of attendees.

     •   Identify terrestrial sensitive environments and resources in an area of observed contamination.

     •   State the number of people who live within 1 mile travel  distance of the site.

     •   Discuss any previous sampling results of sources of surficial materials, including dates and locations.

     •   Discuss SI surficial source samples.  List each sample in  a table and summarize analytical results.

    AIR

     •   Identify the location of, and state the distance to, the nearest individual.  State the population within 4
         miles of the site, including students and workers.  Identify sensitive environments on sources and
         within 4 miles.

     •   Discuss any previous air sampling results, including dates, locations, sampling procedures,  and
         meteorological conditions.

     •   Discuss SI air sampling procedures and results.  Identify  sample  locations on a map. List in a table
         each sample and summarize analytical results.

    SUMMARY AND CONCLUSION

     •   Briefly summarize the major aspects of the site and its history that relate to the release or threatened
         release of hazardous substances and the exposure of targets. Briefly summarize principal pathways and
         targets of concern.

     •   Summarize sampling results, including substances detected in site sources and in environmental media.

    PHOTODOCUMENTATION LOG

      •   As  an attachment, provide photographs of the site taken during the SI depicting pertinent site features
         such as waste source areas, containment conditions, stained soil, stressed vegetation, drainage routes,
         and sample locations.  Describe each photograph in captions or accompanying text.  Key each photo to
         its  location on the site sketch.
   Guidance for Performing Site Inspections Under CERCLA, USEPA, 1992
Evaluation and Reporting
page 12-14

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                   EXHIBIT 6-1: SI NARRATIVE REPORT OUTLINE (concluded)
 APPENDICES

      Analytical results reports

   •   QA Report

   •   Other attachments

 REFERENCES

   •   List, in bibliographic citation format, all references cited in the SI report

   •   Attach copies of references cited in the SI report. Include complete copies of site-specific references
      (e.g., USGS topographic maps, records of communication, drinking water population apportionment and
      calculation worksheets, GEMS and other database printouts, waste handling records or shipping
      manifests).  Include only the title page and pertinent excerpts of publicly available references (e.g.,
      geologic reports).
Guidance for Performing Site Inspections Under CERCLA, USEPA,  1992
                                                                              Evaluation and Reporting
                                                                                             page 12-15

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                          EVALUATION AND REPORTING
                   SI Reporting:  Score and Documentation

           During SI scoring, investigator should:
              • Start at beginning of package and work through systematically
              • Document all assumptions
              • Develop references

           Evaluate SI Results
              • Use Table 6-1, Additional Evaluation of SI Results, to aid in
                decisions
         SI Guidance, section 6.2                                            OH • 18
                   	J
                             SI Reporting:  Reviews

            SI reports and scoresheets undergo three separate reviews
              • SI investigator conducts detailed review of SI report and
                scoresheets for completeness and internal consistency
              • Independent reviewer reviews analytical data and internal
                consistency
              • EPA regional officials and state personnel review reasonableness
                and whether SI objectives were met
         SI Guidance, section 6.3                                            OH • 19
Evaluation and Reporting                                                            4/94
page 12-16

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                         EVALUATION AND REPORTING
                          Site Disposition Decision

           Recommendation based on site scon
              • No further remedial action planned (NFRAP)
              • Expanded SI (if focused SI conducted initially)
              • MRS package preparation
           EPA makes final decision
                                                                  OH* 20
        Notes:
4/94                                                         Evaluation and Repotting
                                                                     page 12-17

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APPENDIX A
  Fact Sheets

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                                                                          PB93-963341
                      United States
                      Environmental Protection
                      Agency
Office of
Solid Waste and
Emergency Response
Directive 9345.1-16FS
EPA540-F-93-038
September 1993
                       Integrating   Removal  and
                       Remedial  Site  Assessment
                       Investigations
   Office of Emergency and Remedial Response
   Hazardous Site Evaluation Division (5204G)
                    Quick Reference Fact Sheet
Increased efficiency and shorter response times are the primary objectives of integrating removal and remedial site
assessment investigations under the Superfund Accelerated Cleanup Model (SACM).  This  is based on the
assumption that there is duplication of effort between the programs.  A critical element of SACM is a continuous
and integrated approach to assessing sites.   The concept of integrating removal and  remedial  site assessment
activities was introduced in Assessing Sites Under SACM—Interim  Guidance (OSWER Publication 9203.1-051,
Volume 1, Number 4, December 1992). This  fact sheet examines areas of duplication and key differences between
the two types of investigations, and describes some approaches for integrating assessments. The primary audience
for this information is the site assessment community which includes  EPA On-Scene Coordinators (OSCs) and Site
Assessment Managers (SAMs), their counterparts in state or other federal agencies, and assessment contractors.
REMOVAL ASSESSMENTS AND
REMEDIAL SITE ASSESSMENTS

Figure 1 illustrates traditional assessment activities of
the removal and remedial programs prior to SACM.
Typically, when EPA is notified of a possible release
(under CERCLA Section 103), the removal program
determines whether there is a need for emergency
response by  EPA.    If  a response  is  deemed
necessary,  an   OSC  and/or  a  removal  program
contractor will visit the site. If circumstances allow,
a file and telephone investigation should be initiated
prior to  the site visit.  The OSC may decide to take
samples during this initial visit or  may postpone
sampling.  EPA can initiate a removal action at any
point in the  assessment  process.   If the  OSC
determines that the site does not warrant a removal
action,  he  may  refer  the site to  remedial  site
assessment  or  the State for further  evaluation, or
recommend no further federal  response action.

The remedial site assessment process is similar to that
of the  removal program.  Once  a  site has  been
 discovered and entered into the CERCLIS data base,
 the SAM directs that  a preliminary assessment (PA)
 be performed  at  the site.  The focus of PA data
 collection is the set of Hazard Ranking System (HRS)
  factors that can be obtained without sampling (e.g.,
  population within 1/4 mile).  The PA includes a file
  and telephone investigation, as well as a site visit (the
  PA reconnaissance, or "recon").   The PA recon
  differs from the typical removal site visit because
  samples are not collected and observations are often
  made from the perimeter of the site (although some
  Regions prefer on-site PA recons).   From the PA
  information, the SAM determines if a site inspection
  (SI) is needed (i.e., whether the site could score
  greater than the 28.5 needed to qualify for inclusion
  on the National Priorities List (NPL)). The SI would
  include sufficient sampling and other information  to
  allow the SAM to determine whether the score  is
  above 28.5.   Even in cases where SI  data are
  adequate for this  decision, it may be necessary  to
  conduct an expanded site inspection (ESI) to obtain
  legally defensible documentation.

   In general,  the  remedial  site  assessment process is
   more  structured than the removal assessment and
   operates on a less intensive schedule. The remedial
   site assessment process is focused on collecting data
   for the HRS, while Removal  assessments  are based
   on whether site conditions meet National Contingency
   Plan (NCP) criteria for a removal action.

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                                      Figure 1:  Traditional Assessment  Processes
                                                REMOVAL PROGRAM
Notification or
  Discovery
                      Site  Inspection
                      (If nece*»iry)
Altaic Whether Incident
Meets NCP Criteria lor a
    Removal  Action
                                                                      YES
                                                   Prepare and Obtain Approval
                                                      of Action Memorandum
                                                                                                                 Initiate Removal
                                                                                                               Action  Site  Actlvltes
                                                       NO
Terminate PA or Refer to Remedial)
   Program or Other Authorities,
         If Appropriate
                                              REMEDIAL  PROGRAM
                                              Removal Actions May Occur at any Stage
Discovery I
           CERCLIS
Preliminary
Assessment
   (PA)
                                              Remedial
                                            Investigation/
                                          Feasibility Study
                                              (RI/FS)
Record of
Decision
(ROD)
	 k
Remedial
Design/
Remedial
Action
                    Site Evaluation Accomplished  (SEA)
                      (Site Screened Out of Process)

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INTEGRATING ASSESSMENT ACTIVITIES

While there  are  differences  in objectives  between
removal   and  remedial  assessments  (i.e.,   NCP
removal  criteria  versus  HRS), many  of the  same
factors are important to both programs:  the potential
for human exposure through drinking  water,  soils,
and   air   pollution;  and   threats   to   sensitive
environments such as wetlands.   Similarities in  the
activities  required by  both assessments—telephone
and  file  investigations,  site  visits or PA  recons,
removal   or  SI sampling  visits—suggest  that  the
activities  can be consolidated.   The  challenge  of
integrating assessments is to organize the activities to
enhance efficiency.

The basic goals of an integrated assessment program
under SACM are:

   •   Eliminate duplication  of effort.

   •   Expedite  the process.  At a  minimum,  avoid
      delays for time-critical removal actions or early
      actions (see Early Action and Long-Term Action
      Under  SACM—  Interim  Guidance,  OSWER
      Publication 9203.1-051, Volume  1, Number 2,
      December 1992,  for details  on early and long-
      term actions).

   •  Minimize the  number of site visits and other
      steps in the process.

   •  Collect only the data needed to assess the site
      appropriately.

 The last point is critical to  enhancing efficiency since
 not all sites need to be assessed in depth for  both
 removal   and  remedial  purposes.    Integrating
 assessments does not mean simply adding together the
 elements of both assessments for all sites—efficient
 decision  points  must  be  incorporated  into  the
 integration process. The elements deemed necessary
 for an integrated assessment depend on the particular
 needs of a  specific site and  could involve similar,
 additional,  or  slightly  different activities  from
 traditional removal  or remedial site assessments.

 Figure 2 shows an approach for  integrating the two
 assessments   and  indicates  ways  to  eliminate
 unnecessary  data  collection.  The most important
 features   of  the  approach  are  the  combined
 notification/site discovery/screening  function; the
 single site visit  for  both  programs;  phased file
searches   as  appropriate;  and  integrated   sample
planning and inspection.  This approach  is detailed
below.

Not I Heat ion/Site Discovery/Screening

This "one door" notification process is a combination
of  the  current  removal  and  remedial   program
notification/discovery.   All remedial  and  removal
program discovered  sites are  screened for  possible
emergency  response.   The  screening  step  would
determine whether there is time for a file search prior
to the initial site visit.

(Classic)  Emergency

If an emergency is identified,  the response would be
implemented  immediately.    Emergency  responses
require immediate sampling and removal  actions and
allow  little or   no  time  for  file  or  telephone
investigations prior to site activity.

File Search

The integrated file search includes all elements of the
current removal assessment   file  search.    All  file
search elements should  be thoroughly documented to
serve the needs of both programs. Table 1 lists data
 elements that are commonly a part of the file search.
 The timing of the file search relative to the  initial site
 visit   would   be   determined   during   the
 notification/screening step.
           Table 1:  File Search and
            Telephone Investigation
         Elements Common to Both Programs
        Regulatory program file search (e.g., RCRA,
        water, stale)
        Site access information and property
        ownership
        Site history,  industrial processes
        Substances used at site
        Past releases (substances, locations, impacts)
        Latitude and longitude
        Topographic maps
          Generally Removal Assessment Only
         Potentially responsible party (PRP) search
         Treatment technology review

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                                               Figure 2:   Integrated Assessment
                                                                                                     No Further Action
                    No Further Action
                          1
     Report
Received/Release
    Identified
Initial Screening
 lor Emergency
   Elglblllty
                                     Classic
                                    Emergency
                                    Response

earch
allows)
1

J
&
I,
1

ample (upuona
I
Inltlsl Field
Investigation I
(Recon) |


1-
->

^
f
Review
Oata/Oeclslon
Further Actli




Complete the
>n Report 1

Do Removal < — No

Time Critical |
Removal? |j~'
n Integr
ECfJ* -x
                                                                                       I
                                                                                     <28.5
Definitely >28.S
                                                                                                        May be
                                                                                                         >28.S
                                                                                                                  Si/Removal
                                                                                                                  Assessment
                                                                                                                Sampling Report
                                                                                                           >28.S
                                                                                                                  Do Removal

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Initial Field Investigation/PA Recon

The  integrated site visit combines elements of both
the removal assessment field visit and the remedial
PA recon.   Because removal and remedial program
site visit activities are similar, only a small increase
in effort would be required to meet the needs of both
programs.   Documentation needs of  remedial  site
assessment might  require  slight revision of removal
assessment procedures. For example, one might need
to document the distance to  the nearest residence, in
addition to locating any  contaminated  residential
properties; for removal assessment needs, one might
need  to assess the  extent of contamination.   The
assessment  team  will  need  to  gain  site  access
approval for the site visit,  in contrast with current
remedial PA recons performed from the perimeter in
some Regions.   Table 2  lists  elements that are
commonly part of the screening site visit.

Sample (Qptionan

Integrated  assessment sampling  should  follow the
current removal  assessment approach,  except that
HRS data  needs  should be considered  in selecting
sample  locations and  laboratory  analyses.    The
emphasis, however, is on removal assessment needs.

Review Data/Decide Further Action

Both removal  and remedial programs would jointly
recommend   a   course  of  action,  taking  into
consideration any previous removal actions.  A site
might undergo either a continuation of the removal
assessment, a remedial site assessment PA,  or both
concurrently.  Alternatively, a time-critical removal
action could be performed prior  to deciding whether
the  site should undergo a PA.   Completing the PA
might be expedited in order to determine early in the
process   whether   remedial   site   assessment
 requirements should be included in sampling plans.
 When  planning the site inspection, the Region may
 also want to  consider the effect  of a  removal action
 on the HRS score (see The Revised Hazard Ranking
 System:   Evaluating Sites After  Waste  Removals,
 OSWER Publication 9345.1-03FS, October  1991).

 Complete the PA

 Collect any information needed  for the remedial site
 assessment that was not part of the earlier file search,
 and calculate the preliminary HRS score.  For sites
 assigned  the SEA  (site evaluation accomplished)
Table  2:  Data Elements of the Site Visit
       Elements Common to Both Programs
      Current human exposure identification
      Sources identification, including locations,
      sizes, volumes
      Information on substances present
      Labels on drums and containers
      Containment evaluation
      Evidence of releases (e.g., stained soils)
      Locations of wells on site and in immediate
      vicinity
      Runoff channels or pathways
      Location of site or sources relative to surface
      waters
      Nearby wetlands identification
      Nearby land uses (e.g.,  residential, schools,
      parks, industrial)
      Distance measurements or estimates for wells,
      land uses (residences and schools), surface
      waters, and wetlands
      Public accessibility (e.g., site fence)
      Blowing soils and air contaminants
      Photodocumentation
      Site sketch
        Generally Removal Assessment Only
       Petroleum releases (eligible)
       Fire and explosion threat
       Urgency of need for response
       Response and treatment alternatives evaluation
       Greater emphasis on specific pathways (e.g.,
       direct contact)
       Sampling
      Generally Remedial Site Assessment Only
       Perimeter survey (in some Regions)
       Number of people within 200 feet
       Some sensitive environments (e.g., endangered
       species habitats)
       Review all pathways
 designation, also complete the PA report.  Depending
 on circumstances and the Region's approach, the PA
 report might be included as part of a comprehensive
 PA/SI report for sites scoring above 28.5. Table 3
 lists typical data elements of this activity.  If after the
 PA it is evident that a site is likely to qualify for the
 NPL, the  site would  be referred  to  the Regional
 Decision  Team  (RDT).   (See  SA CM  Regional
 Decision    Teams—Interim    Guidance,   OSWER
 Publication  9203.1-051,  Volume 1,  Number  5,

-------
                     Table 3:  Data Elements Needed to Complete the PA
      Population within 1 and 4 miles
      All private and municipal wells wilhin 4 miles
      Depth to ground water (sometimes also collected for removal assessment)
      Local or regional geology and climate
      Distance to surface water measured (removal assessment only estimates distance)
      Fisheries along a 15-mile surface water migration pathway
      Sensitive environments along a 15-mile surface water migration pathway
      Size of wetlands
      Preliminary  HRS score
December 1992, for details on the composition and
role of the RDT.)

Integrated Sampling Plan

This combines planning for  the current screening
level  SI  (see  section  2.1  of  the Guidance for
Performing Site Inspections Under CERCLA, OS WER
Directive  9345.1-05,   1992)  and  any   removal
sampling activities not already addressed by the initial
visit.  When it appears  that a remedial action will be
appropriate, and the site looks like a candidate for
NPL  listing, a Remedial Project  Manager (RPM)
should join the OSC and SAM in sample planning to
incorporate the objectives of any potential long-term
actions at the site.  For applicable sites,  this will
enhance  the  efficiency  of  progressing   from
assessment to  remediation,  or  starting a  remedial
investigation prior to   NPL  proposal.   Likewise,
sample planning should anticipate the needs of any
possible engineering evaluation/cost analysis (EE/C A)
that might be needed for subsequent non-time-critical
removal actions.

Si/Removal Assessment Sampling

This is a single sampling event designed to meet the
needs  of both programs, where appropriate.  Along
with  the  site visit and the file search, integrating
sampling would  improve  efficiency.    Table  4
describes differences in emphasis between removal
and remedial site  assessment  sampling  approaches
which need to be considered when developing a joint
sampling plan.

 RDT Decisions

 The RDT determines the course of action  needed  to
 address a site, based  on the  outcome of the site
 assessment PA, Si/removal assessment, and any time-
 critical removal actions. This can include proposing
to list the site on  the  NPL;  conducting  an early
action; starting the remedial investigation (RI) early;
or combining the  Rl with the data collection needed
for listing.

ES1/RI

One option open to the RDT is to start the RI as soon
as it is apparent that the site will qualify for  the NPL
(e.g., after a PA), even if further documentation  is
needed  for NPL  rulemaking.   The needs  of NPL
listing and the RI  can  be integrated  into  a single
sampling  plan  to give  a  headstart to a long-term
action.

Flexibility in Approach

Figure  2  addresses the most  likely approaches  for
screening site assessments; in fact, the approach will
vary  according to the site and other factors.  Time-
critical removal  actions  can occur  at  any  time.
Enforcement,  community  relations,  and  remedial
planning  considerations  can be  factored   into data
 collection as needed at any point along the  process.
 OTHER CONSIDERATIONS

 Methods of recording  or documenting information
 vary between programs.  Documentation  is a major
 consideration  for  both  programs,  but  the  HRS
 requires a specific data set.  In order for  a common
 data element to be  used by  both programs, HRS
 documentation needs to be addressed.

 Timing and duration of the activities  also need to be
 considered by Regional personnel who are setting up
 integrated   assessments.      One  critical   timing
 consideration involves the step "complete the PA."
 At some sites this can proceed on a routine schedule,
 but if a Region decides that sampling is needed to

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                  Table 4:  Site Inspection/Removal Assessment Sampling
                                   Remedial Site Assessment Emphasis
      Attribution to the site
      Background samples
      Ground water samples
      Grab samples from residential soils
      Surface water sediment samples
      HRS factors related to surface water sample locations (e.g., floodplains, watershed area)
      Fewer samples on average (10-30) than removal assessment
      Strategic sampling for HRS
      Contract Laboratory Program (CLP) usage (no separate funding for analytical services)
      Full screening organics and inorganics analyses
      Definitive analyses
      Documentation, including targets and receptors (e.g., maps, census data)
      Computing HRS scores
      Standardized reports
                                      Removal Assessment Emphasis
      Sampling from containers
      Physical characteristics of wastes
      Treatability and other engineering concerns
      On-site contaminated soils
      Composite and grid sampling
      Rapid turnaround on analytical services
      Field/screening analyses
      PRP-lead removal actions
      Goal of characterizing site (e.g., defining extent of contamination)
      Focus on NCP  removal action criteria
determine  whether  to  undertake  a  time-critical
removal action, the PA should be completed before
developing the integrated sampling plan. Otherwise,
the remedial site assessment sampling needs may not
be appropriately factored into the sampling plan. By
collecting enough data to develop a preliminary HRS
score, the Region can determine whether the site may
be eligible for the NPL and whether it is worthwhile
to collect HRS-related samples.  The PA report can
be  combined  with an SI report at a later time, if
appropriate.

An integrated sampling approach implies the need for
a  coherent approach to sample  analysis.    Some
general principles should be followed to avoid major
problems. Analytical data must  be suitable for NPL
purposes.   Analytical services  should include the
appropriate reporting  requirements to allow for data
validation at a later date, if necessary.  Table 5 lists
some data  quality considerations for analytical data
used to support an HRS score.

The focus of  this fact sheet is on  the technical
integration of assessments at sites where there is a
potential for no action,  early actions, or long-term
actions.  In some cases,  the Region will  rule out the
need for one of those,  and the  assessment  process
under SACM will be similar to a traditional removal
or remedial site assessment.

Integration of assessments under SACM  will reduce
duplication of effort at sites by addressing them with
a single assessment approach which incorporates the
objectives of both programs as applicable  to each
site.   Integration of  assessments is  an   efficient
blending  of similar  procedures  which  may  be
 appropriate at some sites and meets the objectives and
 needs of both programs.

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            Table 5:  Analytical  Data  Quality Needs For MRS Observed Releases
      Sampling procedures, location, and conditions documented in field log.
      Chain of custody.
      Field blanks for each parameter for each day of sampling. The concentration of contaminants detected must be at
      least one order of magnitude below corresponding sample results.
      Initial 2-point calibration.  Low level standard at or below concentration level of concern.  High concentration
      standard no more than 2 orders of magnitude above the low concentration standard.
      Continuing calibration using low level concentration standard  after 10 to  15 sample analyses, or at the end of the
      day/sampling event, whichever occurs first.  (This step ensures consistent instrument response.)
      Blanks run after high level samples to avoid cross contamination.
 Specific examples of acceptable field methods:
    •  X-ray fluorescence (XRF) for metals with site-specific standard matrix or with 10 percent lab confirmation by
      accepted EPA atomic absorption (AA) method.
    •  Field headspace or vadose zone VOC analysis with site specific standards, coupled with previous site information
      such as spill composition, 10 percent split for verification by an accepted EPA method, or successful field
      analysis of a PE or reference sample.
                                  Additional copies can be obtained from:
             Public                                                 EPA Employees
National Technical Information Service (NTIS)          or            Superfund Documents Center
U.S. Department of Commerce                                       U.S. Environmental Protection Agency
5285 Port Royal Road                                               401 M Street, SW (OS-245)
Springfield, VA 22161                                              Washington,  DC  20460
(703) 487^650                                                     (202) 260-9760 or (202) 260-2596 (FAX)
Order  #:  PB93-963341
United States
Environmental Protection Agency
5204G
Washington, DC 20460

$300 Penalty for Private Use
                                                      8

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                        United States
                        Environmental Protection
                        Agency
                            Office of
                            Solid Waste and
                            Emergency Response
    &EPA
Directive 9285.7-14FS
PB94-963311
EPA/540/F-94/028
July 1994
Using  Qualified  Data  to
Document  an  Observed   Release
  Office of Emergency and Remedial Response
  Hazardous Site Evaluation Division (5204G)
                                              Quick Reference Fact Sheet
Abstract

Data validation checks the accuracy of analytical data, and qualifies results that fall outside performance criteria of
the Contract Laboratory Program (CLP). Results qualified with a "J" are  estimated concentrations that may be
biased, but may be used to determine an observed release in Hazard Ranking System (HRS) evaluation.  This fact
sheet explains the conditions for use of V-qualified data, and introduces factors which compensate for variability
and enable their use in HRS evaluation.
Why Qualify Data?

Chemical  concentration  data  for  environmental
decision-making  are  generated  using  analytical
methods.  EPA  analytical  chemistry methods are
designed  to  provide   the   definitive   analyte
identification and quantitation needed to establish an
observed release under the Hazard Ranking System
(HRS).  Routine operational variations in sampling
and analysis inevitably introduce a degree of error
into the analytical data.  Data validation checks the
usability of the analytical data for HRS evaluation and
identifies the error  (bias) present. The validation
process qualifies the biased data.  Certain types of
qualified data for release and background samples
may be used to determine an observed release.
EPA Data Qualifiers

EPA analytical methods (e.g., SW-846 and Contract
Laboratory Program [CLP])  introduce a number of
Quality   Assurance/Quality   Control  (QA/QC)
mechanisms during the course of sample analysis to
measure  qualitative  and quantitative accuracy.3/w
Such mechanisms include matrix spikes, matrix spike
duplicates, laboratory control samples, surrogates,
blanks, laboratory  duplicates, and quarterly blind
performance evaluation (PE) samples.  Surrogates
and spikes are chemically similar to the analytes of
interest   and   thus  behave   similarly during  the
analytical process.  They are introduced or "spiked"
                            at a known concentration into  the field  samples
                            before  analysis.    Comparison  of  the   known
                            concentrations of the surrogates and spikes with their
                            analytical results measures accuracy, and may indicate
                            bias caused by interferences from the sample medium
                            (matrix effect).1*9    Laboratory  control  samples
                            contain known  concentrations of target analytes and
                            are analyzed in the same batch  as field samples.
                            Their  results  are  used  to  measure laboratory
                            accuracy.   Blanks  are  analyzed to  detect any
                            extraneous contamination  introduced either in  the
                            field or in the laboratory.   Laboratory duplicates
                            consist of one  sample that undergoes  two  separate
                            analyses;  the results are  compared  to determine
                            laboratory precision. Quarterly blind PE samples also
                            evaluate lab precision.

                            CLP  and other EPA  analytical methods  include
                            specifications  for  acceptable  identification, and
                            minimum and maximum  percent recovery of  the
                            target  analytes and QA/QC compounds.  Data are
                            validated   according  to   guidelines  which  set
                            performance  criteria for instrument calibration,
                            analyte identification, and  identification and recovery
                            of the QA/QC  compounds. M*   The  National
                            Functional Guidelines for Data Review used in EPA
                            validation were designed for data generated under the
                            CLP  organic and inorganic analytical  protocols.1*3'4
                            The guidelines do not preclude the validation of field
                             and non-CLP data; many EPA Regions have adapted
                             the National Functional Guidelines for Data Review to
                            validate non-CLP data. Data which do not meet the

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guidelines'  performance  criteria  are  qualified  to
indicate bias or QC deficiencies. The data validation
report  usually explains why the data were qualified
and indicates  the direction of  bias when it can be
determined. Most EPA validation guidelines use the
data qualifiers presented  below.  u   (Other  data
qualifiers besides these are in use; always check the
validation report  for the exact  list of qualifiers and
their meanings.)

   •  "U" qualifier - the analyte was  analyzed for,
      but was not detected  above  the  reported
      sample  quantitation  limit.     For  practical
      purposes, "U" means "not detected"; the result
      U  usable   for   characterizing   background
      concentrations for HRS evali"»tion.3

   •  M"  qualifier ~  the analyte  was  positively
      identified;  the associated numerical value is
      the approximate, concentration of the analyte in
      the sample.  "J" data are biased, but provide
      definitive analyte identification, and are usually
      reliable.  They  may be used to determine an
      observed release under  conditions  specified
      later in this fact sheet. 5

   •  "N" qualifier --  the  analysis  indicates  the
      presence of  an analyte  for which  there is
      presumptive  evidence to make  a  "tentative
      identification."  "N" data are not sufficiently
      definitive for HRS evaluation.

   •  "NJ" qualifier  -  the analysis indicates  the
      presence  of an   analyte  that  has  been
      "tentatively  identified"   and  the  associated
      numerical  value  represents its  approximate
      concentration.  "NJ" data are  not sufficiently
      definitive for HRS evaluation.   .

   .  "UJ" qualifier -- the analyte was not detected
      above the reported sample quantitation limit.
      However, the reported  quantitation limit is
      approximate  and may or may not represent the
      actual   limit of  quantitation   necessary  to
      accurately and precisely measure the analyte in
      the sample. "UJ"  non-detects are not definite;
      the analyte may be  present.  The result can be
      used to document  non-detects in background
      samples under certain conditions.

   .  "R" qualifier -- the  sample results are rejected
      due  to  serious deficiencies in the  ability to
      analyze the sample and meet quality control
      criteria.   The presence or absence  of the
      analyte cannot be verified.  EPA does not use
      "R"  data   because  they  are   considered
      unreliable.5

Validrted data that are not qualified are unbiased,
and can  be used at their reported values for HRS
evaluation.
Criteria for Determining an Observed Release with
Chemical  Data

Chemical data demonstrate an observed release when
all of the following are true:

1.  The release of a  hazardous substance is at least
   partially    attributable   to   the   site    under
   investigation.

2.  The release sample concentration is greater than
   or equal to the appropriate detection limit (e.g.,
   sample quantitation limit [SQL]).

3.  If background levels are below detection  limits,
   the release sample concentration must be greater
   than its detection limit, or, if background levels
   are greater than or equal to detection limits, the
   release sample concentration  must be  at least
   three times the background concentration.7
Direction of Bias in T-Qualified Data

It is important to understand the bias associated with
"J"-qualified  data  when  using  them   for  HRS
evaluation.     "J"  data may  have  high,  low,  or
indeterminate bias.   A low bias means that the
reported    concentration   is   most   likely   an
underestimate  of  the  true  concentration.    For
example,  data may  be biased  low when  sample
holding times for volatile organic compounds (VOCs)
are  exceeded  or  when the  recovery  of  QA/QC
compounds is significantly  less than the true amount
originally introduced into  the sample.  A high  bias
means that the reported concentration is most likely
an overestimate of the true concentration. A bias is
indeterminate  when  it  is impossible  to ascertain
whether the concentration is  an overestimate or an
underestimate.  For example, an indeterminate bias
could result when matrix effects  obscure QA/QC
compounds.

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Qualified Data and Direction of Bias

Qualified data  may  be  used  when  it  can  be
demonstrated  that the data meet the HRS rule  for
determining an observed release despite the bias in
the reported concentrations. This condition depends
on the direction of bias:  low bias data may be used
for release samples, and high bias data may be used
for background samples.  Low bias release samples
are underestimates of true concentration.   Under-
estimated release concentrations  that still meet  the
HRS   criteria  (e.g.,   they  are  still  three times
background  level)  clearly  establish an  observed
release.    High  bias background  samples   are
overestimates   of  background  level.     If   the
concentration  of  unbiased  release  samples  still
significantly  exceeds  an  overestimated  background
level according to HRS criteria, an observed release
is clearly established.  Similarly, an observed release
is  established  when low bias release concentrations
significantly   exceed   high   bias   background
concentrations according to the HRS criteria.

These scenarios show that low bias "J-"qualificd data
may be used  for release  samples at their reported
concentrations, and that high bias "J-"qualified data
may be  used for background  samples  at  their
reported concentrations.

High bias release samples may not be used at their
reported  concentrations   because  they  are   an
overestimate  of true concentration;    the  true
concentration  might be less than the HRS criteria for
an observed release. The  reported concentration for
low bias background concentrations  may  not  be
compared to release samples because it is most likely
an  underestimate of background level;  the release
sample concentration might not significantly exceed
the background concentration.  However, high bias
release data and low bias background  data may be
used with factors which compensate for the variability
in the data.  The factors will enable these  types of
biased data to meet HRS criteria for determining an
observed release.

Factors for Biased Data:  Tables 1 through 4 (pages
6-13) present  analvte-specific factors to address the
uncertainty  when  determining an observed release
using high bias release data and low bias background
data.  The factors are derived from percent recoveries
of  matrix spikes, surrogates, and laboratory control
samples in  the CLP Analytical  Results Database
(CARD) from January 1993 to March 1994.
The range of CARD data for each analyte includes 95
percent of all percent recoveries. Discarding outliers
left 95  percent  of the  CARD data available for
calculating  factors. The factors are ratios of percent
recovery values at  the 97.5 and 2.5 percentiles. The
ratios generally show a consistent pattern.

An attempt to "convert" a biased  value to its true
concentration  is  not  recommended because  the
CARD   data  do  not  differentiate  and  quantify
individual  sources of  variation.   The  factors are
applied as "safety factors" to ensure that biased data
can be used to meet HRS criteria for determining an
observed release.  Dividing a high bias value by a
factor effectively deflates it from the high end of the
range to the low end (low bias • alue). Multiplying a
low bias value by the factor effectively inflates it to a
high bias value.  Use of the ratio of percentiles is a
"worst-case" assumption that the data are biased by
the extent  of the range  of CARD  data considered.
The factors either inflate the values to the high end of
the range, or deflate the data to the low end, and thus
compensate  for  the   apparent  variability  when
comparing a high bias  value to a low bias  value (see
Exhibit 1).

Factors have been selected for all analytes in the CLP
Target Compound List (organic analytes) and Target
Analyte List  (inorganic  analytes).   Some organic
factors  were  derived  from  matrix spike percent
recoveries,  and  some  from  surrogate  percent
recoveries, depending on availability of  data. When
both matrix spike and surrogate data were available
for   the  same  compound,  the  larger  value
(representing more  extreme  high  and  low percent
recoveries) was used.  Laborato.y  control samples
were used to calculate some of the inorganic factors.
A default  factor of  10 was used  for analytes when
percent recovery data  were unavailable.

Application of the Factors:  Exhibit 1 shows how to
apply the  factors to "J"  qualified  data.  High  bias
background data, low bias release  data,  and unbiased
data may  be  used at  their reported concentrations.
Multiply low bias background sample data by the
analvte-specific factor  to bring them  to  their  new
value. The new background value -ffectively becomes
 a high bias value that may be used to determine an
 observed release.  Divide  high bias release sample
 data by the analyte-specific factor to bring them  to
 their  new  value.   The  new  release sample  value
 effectively becomes a low bias result that may be used

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Exhibit 1: Use of Factors for "J"-Qualified Data
Type of Sample
Background
Sample
Release
Sample
Type of Bias
No Bias
Low Bias
High Bias
Unknown Bias
No Bias
Low Bias
High Bias
Unknown Bias
Action Required
Nona: Use concentration without factor
Multiply concentration by factor
None: Use concentration without factor
Multiply concentration by factor
None: Use concentration without factor
None: Use concentration without factor
Divide concentration by factor
Divide concentration by factor
to determine an observed release.  Note:  Adjusted
release and background values must still meet HRS
criteria (e.g.,  release concentration must be at least
three times background level) to determine an observed
release.
Examples Using Trichloroethene in Soil:

7.  Release sample  data  biased  low,  background
   sample data biased high.
Release sample value:
Background sample value:
30 MgAg GO low bias
10 /xg/kg (J) high bias
In this instance, the direction of the bias indicates
that  the  release  sample  concentration  exceeds
background by more than three times, so an observed
release is established (provided all other HRS criteria
are met).  Use of the factors is not needed.

2.  Release sample data unbiased, background sample
   data biased low.
                                     no bias
Release sample value:       30
Background sample value:   10
To use the data to establish an observed  release,
multiply the background sample value by factor given
for trichloroethene (1.8). No factor is needed for the
release sample.

New background sample value:
(10 /ig/kg) x (1.8) = 18 /xg/kg (J) high bias
                             The release sample concentration does not exceed the
                             new  background level by a factor of three,  so  an
                             observed release is not established.

                             3.  Release sample  data  biased  high,  background
                                sample data unbiased.
                             Release sample value:     75 jigAg (-0 high
                             Background sample value: 15 MgAg   no bias
                                                        To use  the  data to establish  an observed release,
                                                        divide the release  sample value by  the  factor for
                                                        trichloroethene  (1.8).  No factor is needed for the
                                                        background sample.

                                                        New release sample value:
                                                        (75 jig/kg) 4- (1.8) =  42 Mg/kg (J) low bias

                                                        The  new release  sample  concentration  does not
                                                        exceed background concentration by a factor of three,
                                                        so an observed release is not established.

                                                        4.  Release sample data  biased high,  background
                                                           sample data biased low.
                             Release sample value:     100 /xg/kg (J) high bias
                             Background sample value: 10 /tg/kg (J) low bias

                             To use the data to establish an  observed  release,
                             divide the release  sample value  and  multiply the
                             background sample value by the factor given for
                             trichloroethene in soil (1.8).

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New release sample vaiue:
(100 Mg/kg) •«• (1.8) =  56 Mg/kg (J) low bias

New background sample value:
(10 Mg/kg) x (1.8) = 18 Mg/kg (J) high bias
The new release sample concentration is three times
the new background  concentration, so an observed
release is established,  provided all other HRS criteria
are met.

Documentation Requirements for Use of Qualified
Data: When using T-qualified data to determine an
observed release, include the T-qualifier commentary
from the data validation report in the HRS package.
This step will ensure that the direction of bias  is
documented.

Use of Other Factors: EPA Regions may substitute
higher factor values other than the ones in this fact
sheet on  a  case-by-case  basis  when  technically
justified. For example, other factors may be applied
to conform with site-specific Data Quality Objectives
(DQOs)  or  with  Regional  Standard  Operating
Procedures (SOPs).10

Detection Limit Restrictions:  Factors may only be
applied to "J" data with concentrations above the CLP
Contract Required Quantitation  Limit (CRQL) or
Contract Required Detection Limit  (CRDL).  T-
qualified  data  with   concentrations  below  CLP
detection limits cannot  be used to  document an
observed release.
Use of "UJ"-Qualified Data

A combination of the "U" and "J"  qualifiers indicates
that the reported value may not accurately represent
the concentration necessary to detect the analyte in
the sample.  Under limited conditions, "UJ" data can
be used to represent background when determining
an  observed  release.   These conditions  include
instances  when  there  is   confidence  that  the
background concentration has not been detected and
the sample measurement that establishes the observed
release  equals  or  exceeds   the  SQL  or  other
appropriate detection limit. This reasoning is  based
on  the presence of a high bias in the background
sample. Thus, UJ data can be used only when all of
the following conditions apply:

   •  The "UJ" value applies to  the background
      sample and represents the detection limit,

   •  The "UJ" value is biased high, and

   •  The release sample concentration exceeds the
      SQL (or  applicable  detection limit)  and is
      unbiased or biased low.
Summary

Data validation checks the usability of analytical data
and identifies certain errors (bias).  "J"-qualified data
identify that analytes are  present,  but the reported
values represent estimated concentrations associated
with bias.   Low bias release  data  and high bias
background data may be used at the reported values.
High bias release data and low bias background data
may not be used at their reported  concentrations
because  they do not establish  an  observed  release
with certainty.  Application of factors introduced in
this  fact sheet compensate for  this u icertainty, and
enable "J" data to be used to determine an observed
release.

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Table 1: Factors for Volatile Organic Analytes
VOLATILE
ORGANIC
ANALYTES
1,1,1-TRICHLOROETHANE
1 .1 ,2,2-TETRACHLOROETHANE
1,1,2-TRICHLOROETHANE
1,1-DICHLOROETHANE
1,1-DICHLOROETHENE
1,2-DICHLOROETHANE
1,2-DICHLOROETHENE (TOTAL)
1,2-DICHLOROPROPANE
2-BUTANONE
2-HEXANONE
4-METHYL-2-PENTANONE
ACETONE
BENZENE
BROMODI'CHLOROMETHANE
BROMOFORM
BROMOMETHANE
CARBON DISULFIDE
SOIL MATRIX
Number of
CARD
Samples
Reviewed
«
11144
—
11144
2064
11144
11144
—
11144
11144
11144
11144
2060
—
-
11144
11144
Factor
10.0
1.5
10.0
1.4
2.4
1.4
1.4
10.0
1.4
1.5
1.5
1.4
1.7
10.0
10.0
1.4
1.4
WATER MATRIX
Number of
CARD
Samples
Reviewed
—
9180
-
9179
1484
9179
9179
—
9179
9180
9180
9179
1482
-
-
9179
9179
Factor
10.0
1.2
10.0
1.3
2.0
1.3
1.3
10.0
1.3
1.2
1.2
1.3
1.5
10.0
10.0
1.3
1.3

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Table 1: Factors for Volatile Organic Analytes (continued)
VOLATILE
ORGANIC
ANALYTES
CARBON TETRACHLORIDE
CHLOROBENZENE
CHLOROETHANE
CHLOROFORM
CHLOROMETHANE
CIS-1 ,3-DICHLOROPROPENE
DIBROMOCHLOROMETHANE
ETHYLBENZENE
METHYLENE CHLORIDE
STYRENE
TETRACHLOROETHENE
TOLUENE
TRANS-1 ,3-DICHLOROPROPENE
TRICHLOROETHENE
VINYL CHLORIDE
XYLENE (TOTAL)
SOIL MATRIX
Number of
CARD
Samples
Reviewed
-
2058
11144
11144
11144
—
-
11144
11144
11144
11144
2029
-
2046
11144
11144
Factor
10.0
1.6
1.4
1.4
1.4
10.0
10.0
1.5
1.4
1.5
1.5
2.0
10.0
1.8
1.4
1.5
WATER MATRIX
Number of
CARD
Samples
Reviewed
-
1480
9179
9179
9179
~
-
9180
9179
9180
9180
1468
-
1452
9179
9180
Factor
10.0
1.4
1.3
1.3
1.3
10.0
10.0
1.2
1.3
1.3
1.2
1.4
10.0
1.5
1.3
1.2

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Table 2: Factors for Semivolatile Organic Analytes
SEMIVOLATILE
ORGANIC
ANALYTES
1 ,2,4-TRICHLOROBENZENE
1,2-DICHLOROBENZENE
1,3-DICHLOROBENZENE
1,4-DICHLOROBENZENE
2,2'-OXYBIS(1 -CHLOROPROPANE)
2,4,5-TRICHLOROPHENOL
2,4,6-TRICHLOROPHENOL
2,4-DICHLOROPHENOL
2.4-DIMETHYLPHENOL
2.4-DINITROPHENOL
2,4-DINITROTOLUENE
2,6-DINITROTOLUENE
2-CHLORONAPHTHALENE
2-CHLOROPHENOL
2-METHYLNAPHTHALENE
2-METHYLPHENOL
2-NITROANILINE
2-NITROPHENOL
3,3'-DICHLOROBENZIDINE
3-NITROANILINE
4.6-DINITRO-2-METHYLPHENOL
4-BROMOPHENYL-PHENYL ETHER
4-CHLORO-3-METHYLPHENOL
4-CHLOROANILINE
4-CHLOROPHENYL-PHENYL ETHER
4-METHYLPHENOL
SOIL MATRIX
Number of
CARD
Samples
Reviewed
1978
11899
11899
1980
11899
11889
11889
11896
11896
11889
1979
11889
11889
1930
11896
118f)9
11Q89
11?96
11898
-
--
-
1927
11896
11899
11899
Factor
3.5
3.8
3.8
3.8
3.8
8.9
8.9
4.0
4.0
8.9
3.4
8.9
8.9
3.2
4.0
3.8
8.9
4.0
4.3
10.0
10.0
10.0
3.6
4.0
8.9
3.8
WATER MATRIX
Number of
CARD
Samples
Reviewed
1375
7951
7951
r-73
7951
7952
7952
7949
7949
7952
1375
7952
7952
1376
7949
795.
7952
7949
7951
-
-
-
1375
7949
7952
7951
Factor
2.9
4.0
4.0
3.0
4.0
3.6
3.6
2.5
2.5
3.6
2.6
3.6
3.6
2.9
2.5
4.0
3.6
2.5
6.0
10.0
10.0
10.0
3.5
2.5
3.6
4.0

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Table 2: Factors for Semivolatile Organic Analytes (continued) |
SEMIVOLATILE
ORGANIC
ANALYTES
4-NITROANIUNE
4-NITROPHENOL
ACENAPHTHENE
ACENAPHTHYLENE
ANTHRACENE
BENZO(A)ANTHRACENE
BENZO(A)PYRENE
BENZO(B)FLUORANTHENE
BENZO(G,H,I)PERYLENE
BENZO(K)FLUORANTHENE
BIS(2-CHLOROETHOXY)METHANE
BIS(2-CHLOROETHYL)ETHER
BIS(2-ETHYLHEXYL)PHTHALATE
BUTYL'BENZYLPHTHALATE
CARBAZOLE
CHRYSENE
DI-N-BUTYLPHTHALATE
DI-N-OCTYLPHTHALATE
DIBENZ(A,H)ANTHRACENE
DIBENZOFURAN
DIETHYLP.HTHALATE
DIMETHYLPHTHALATE
FLUORANTHENE
FLUORENE
HEXACHLOROBENZENE
HEXACHLOROBUTADIENE
HEXACHLOROCYCLOPENTADIENE
SOIL MATRIX
Number of
CARD
Samples
Reviewed
11889
1905
1965
11889
•
11898
--
--
—
--
11896
11899
11898
11898
--
11898
-
-
11889
11889
11889
11889
-
11889
--
11896
11889
Factor
8.9
4.8
3.1
8.9
10.0
4.3
10.0
10.0
10.0
10.0
4.0
3.8
4.3
4.3
10.0
4.3
10.0
10.0
8.9
8.9
8.9
8.9
10.0
8.9
10.0
4.0
8.9
WATER MATRIX
Number of
CARD
Samples
Reviewed
7952
1368
1361
7952
-
7951
--
-
—
-
7949
7951
7951
7951
--
7951
-
--
7952
7952
7952
7952
--
7952
--
7949
7952
Factor
3.6 I
4.5 I
3.0 I
3.6
10.0 I
6.0
10.0 |
10.0
10.0
10.0 I
2.5 I
4.0 I
6.0 I
6.0
10.0 ||
6.0
10.0
10.0 I
3.6 I
3.6 I
3.6 |
3.6
10.0 I
3.6
10.0 I
2.5 I
3.6 I

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Table 2: Factors for Semivolatile Organic Analytes (continued)
SEMIVOLATILE
ORGANIC
ANALYTES
HEXACHLOROETHANE
4-NITROPHENOLINDENO(1 ,2,3-CD)PYRENE
ISOPHORONE
N-NITROSO-DI-N-PROPYLAMINE
N-NITROSODIPHENYLAMINE (1)
NAPHTHALENE
NITROBENZENE
PENTACHLOROPHENOL
PHENANTHRENE
PHENOL
PYRENE
SOIL MATRIX
Number of
CARD
Samples
Reviewed
11899
--
11896
1966
—
11896
11896
1895
—
1924
1901
Factor
3.8
10.0
4.0
3.7
10.0
4.0
4.0
18.8
10.0
3.2
8.3
WATER MATRIX
Number of
CARD
Samples
Reviewed
7951
-
7949
1345
--
7949
7949
1359
-
1368
1369
Factor
4.0
10.0
2.5
3.7
10.0
2.5
2.5
3.7
10.0
3.5
4.9
10

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Table 3: Factors for Pesticide/PCB Analytes
PESTICIDE/PCB
ANALYTES
4,4'-DDD
4,4'-DDE
4,4'-DDT
ALDRIN
ALPHA-BHC
ALPHA-CHLORDANE
AROCLOR-1016
AROCLOR-1221
AROCLOR-1232
AROCLOR-1242
AROCLOR-1248
AROCLOR-1254
AROCLOR-1260
BETA-BHC
DELTA-BHC
DIELDRIN
SOIL MATRIX
Number of CARD
Samples Reviewed
~
~
1801
1870
—
—
—
—
—
-
-
—
--
-
-
1886
Factor
10.0
10.0
7.4
7.9
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
6.2
WATER MATRIX
Number of CARD
Samples Reviewed
-
--
1353
1350
-
-
23305
23305
23305
23305
23305
23305
23305
-
-
1350
Factor
10.0
10.0
4.6
4.8
10.0
10.0
8.7
8.7
8.7
8.7
8.7
8.7
8.7
10.0
10.0
2.8
11

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Table 3: Factors for Pesticide/PCB Analytes (continued)
PESTICIDE/PCB
ANALYTES
ENDOSULFAN 1
ENDOSULFAN II
ENDOSULFAN SULFATE
ENDRIN
ENDRIN ALDEHYDE
ENDRIN KETONE
GAMMA-BHC (UNDANE)
GAMMA-CHLORDANE
HEPTACHLOR
HEPTACHLOR EPOXIDE
METHOXYCHLOR
TOXAPHENE
SOIL MATRIX
Number of CARD
Samples Reviewed
—
-
-
1866
-
—
1872
-
1877
—
—
-
Factor
10.0
10.0
10.0
8.5
10.0
10.0
4.5
10.0
4.5
10.0
10.0
10.0
WATER MATRIX
Number of CARD
Samples Reviewed
-
-
-
1348
-
-
1350
'-
1351
—
—
-
Factor
10.0
10.0
10.0
3.4
10.0
' 10.0
3.1
10.0
3.6
10.0
10.0
10.0
12

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Table 4: Factors for Inorganic Analytes
INORGANIC
ANALYTES
ALUMINUM
ANTIMONY
ARSENIC
BARIUM
BERYLLIUM
CADMIUM
CALCIUM
CHROMIUM
COBALT
COPPER
CYANIDE
IRON
LEAD
MAGNESIUM
MANGANESE
MERCURY
NICKEL
POTASSIUM
SELENIUM
SILVER
SODIUM
THALLIUM
VANADIUM
ZINC
SOIL MATRIX
Number of CARD
Samples Reviewed
1147
1153
1208
1149
1150
1148
1163
1148
1153
1154
884
1149
1331
1143
1151
1563
1150
-
1190
1152 ..
-
1197
1152
1154
Factor
1.5
1.8
1.6
3.3
1.2
1.3
1.2
1.2
1.2
1.1
1.4
1.2
1.3
1.2
1.2
1.7
1.2
10.0
2.3
1.6
10.0
1.7
1.2
1.3
WATER MATRIX
Number of CARD
Samples Reviewed
1686
1688
1701
1686
1686
1685
1685
1686
1685
1683
-
1687
1727
1686
1685
-
1685
-
1695
1684
-
1691
1685
1689
Factor
1.2
1.2
1.2
1.1
1.2
1.2
1.1
1.2
1.2
1.2.
10.0
1.2
1.2
1.1
1.2
10.0
1.2
10.0
1.3
1.3
10.0
1.2
1.1
1.2
13

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References

1.  U.S. Environmental  Protection  Agency,  1994.
   CLP National Functional Guidelines for Inorganic
   Data  Review.  Office   of  Solid  Waste   and
   Emergency Response.  Publication 9240.1-05-01.

2.  U.S. Environmental  Protection  Agency,  1993.
   CLP National Functional Guidelines for Organic
   Data  Review.  Office   of  Solid  Waste   and
   Emergency Response.  Publication 9240.1-05.

3.  U.S. Environmental  Protection  Agency,  1991.
   Contract Laboratory Program Statement of Work for
   Inorganics Analysis. Document No. ILM02.0

4.  U.S. Environmental  Protection  Agency,  1991.
   Contract Laboratory Program Statement of Work for
   Organics  Analysis.  Office of  Solid  Waste  and
   Emergency Response.  Document No. OLM1.8

5.  U.S. Environmental  Protection  Agency,  1992.
   Hazard Ranking System Guidance Manual. Office
   of  Solid  Waste   and  Emergency   Response.
   Directive 9345.1-07.
6.  U.S. Environmental  Protection  Agency,  1991.
   Guidance for Performing Preliminary Assessments
   Under  CERCLA.   Office of Solid  Waste  and
   Emergency Response. Publication 9345.0-01A.

7.  U.S. Environmental  Protection  Agency,  1992.
   Guidance for Performing  Site Inspections  under
   CERCLA. Office of Solid Waste and Emergency
   Response.  Directive 9345.1-05.

8.  U.S. Environmental  Protection  Agency,  1992.
   Quality  Assurance/Qualify  Control  Samples.
   Environmental Response Team Quality Assurance
   Technical Information Bulletin.

9.  U.S. Environmental Protection Agency, 198o.  Test
   Methods for Evaluating Solid  Waste (SW-846):
   Physical and Chemical  Methods.  Office of Solid
   Waste and  Emergency Response. Document No.
   SW-846.

10. U.S. Environmental Protection Agency, 1993.
   Data Quality Objectives  Process for Superfund.
   Office of Emergency and Remedial Response.
   Directive 9355.9-01.
                                                  14

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15

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                                      Additional copies can be obtained from:

                                   National Technical Information Service (NTIS)
                                          U.S. Department of Commerce
                                              5285 Port Royal Road
                                              Springfield, VA 22161
                                                 (703) 487-4650
                                                Order #94-963311
United States
Environmental Protection Agency
5204G
Washington, DC 20460

$300 Penalty for Private Use

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                    United States
                    Environmental Protection
                    Agency
Office of
Solid Waste and
Emergency Response
Directive 9285.7-19FS
PB94-963313
EPA/540/F-94/030
October 1994
  &ERA      Establishing   Background   Levels
   Office of Emergency and Remedial Response
   Hazardous Site Evaluation Division (5204G)
                                                   DRAFT
                             Quick Reference Fact Sheet
Abstract

The Hazard Ranking System (HRS) establishes criteria for documenting an observed release and observed contamination.
There must be evidence of a hazardous substance in the medium of concern at a concentration significantly above the
background level, and some portion of the release and the hazardous substance must be attributable to the site. This fact
sheet defines background, describes background level determination, and emphasizes the necessity of strategic, efficient
sampling. Background considerations for each HRS pathway are presented.
Introduction

Background level is "the concentration of a hazardous
substance that provides a defensible reference point that
can be used to evaluate whether or not a release  from
the site  has  occurred.  The background level should
reflect the concentration of the hazardous substance in
the medium of concern for the environmental setting on
or near  a site. Background level does not necessarily
represent pre-release conditions, nor conditions in the
absence  of  influence  from sourcc(s) at  the  site."  '
Background  levels  do  not  have  to reflect pristine
conditions; they define concentrations of contaminants
outside the influence of a release.

Background  level determination, usually by chemical
analysis, is necessary to document  an observed release
and to  establish attribution  of contaminants where
multiple  sources or  contaminant contributors   exist
When evaluating a release, the background level of a
substance is  compared with the concentration of the
release  sample(s).  Background and release samples
generally should be collected during the same sampling
event and from the same geologic stratum or medium of
concern.   Time  differences  between  release   and
background samples become critical when analytical
holding times are short (e.g., volatile organic analysis and
hexavalent chromium). Collect release and background
samples   within the  shortest  time   period  possible,
preferably on the  same day.   Obtaining suitable
background samples  can  be challenging because of
varying  media  compositions  and  potentially  false
assumptions regarding data representativeness. Consult
         the  Guidance for Performing Site Inspections Under
         CERCLA, 1992, OSWER Directive 9345.1-05, for further
         information on establishing background levels.
         Resource Considerations

         Determining a  background level  is  important  for
         evaluating an observed release and attribution. Only a
         few background samples  are usually necessary.   The
         selection of strategic sampling locations is critical to the
         success of the Site Inspection (SI), which is a limited-
         scope biased sampling event. Evaluate the benefits of
         sampling at specific locations and assess the validity of
         available data  to meet  SI objectives and conserve
         resources (see exhibits 1 and 2).
         Background Level Determination Without Sampling

         Establishing background level requires determining the
         concentration level of a hazardous substance; it does not
         always require sampling.  Often,  the contaminant of
         concern is  ubiquitous (e.g., lead),  and sampling is
         required to establish a background level. However, some
         man-made  hazardous substances  (e.g.,  chlorinated
         organic solvents,  pesticides,  short-lived radioactive
         substances) can be attributed  only to a contaminant
         source.  In areas that are isolated or where no other
         sources can  be identified, the  presence  of these
         substances in release samples is sufficient documentation
         of contamination; a  background sample is not needed.1
         (However, certain low-level chlorinated organic com-

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   Exhibit 1:     Direct Observation and Chemical
                 Analysis

   The HRS documents an observed release in one
   of two ways:  by direct observation, or by
   chemical analysis.

   Direct Observation: Material containing a
   hazardous substance from the site is observed
   entering or is known to have been deposited
   directly into or otherwise has come to be located
   in the medium (e.g., an effluent discharge from
   the site to surface water).  No background
   sampling is required if direct observation is
   documented.  However, the presence of a
   hazardous substance in the release must be
   documented, preferably by chemical analysis. A
   demonstrated adverse effect also may be used to
   document an observed release by direct
   observation in the air and surface water
   pathways.

   Chemical Analysis:  There is analytical evidence
   of a hazardous substance in a medium, at a
   concentration significantly above the background
   level, and attributable wholly or in part to the
   site or source.

   Criteria for observed release by chemical
   analysis (Refer to Table 2-3 in the Hazard
   Ranking System, Final Rule, 40 CFR Part 300):

     • "If the background concentration is not
       detected  (or is less than the detection limit),
       an observed release is established when the
       sample measurement equals or exceeds the
       sample quantitation limit."
     • "If the background concentration equals or
       exceeds the detection limit, an observed
       release is established when the sample
       measurement is 3 times or more above the
       background concentration.'	
-pounds in aqueous samples  may  be associated with
drinking water chlorination.)

In some cases,  a sample location may serve as its own
background location.2 For example, a ground water well
or surface water intake may have associated historical
analytical data.  A release can be demonstrated  when
historical data from a contaminated well or intake show
that  it  was   previously   uncontaminated  or   less
contaminated.   Detailed historical  data  are useful  to
define encroachment of a contaminant plume. Often,
historical data are available for wells and surface water
intakes at industrial sites or municipal water facilities
which have a regular monitoring program.'
   Exhibit 2:     Reasons for Collecting
                 Background Samples

     •  A release cannot be determined by direct
       observation
     •  The source consists of contaminated soil
     •  Historical  data are unavailable or
       in.Mifficie.nt
     •  The substance of interest is ubiquitous
Some substances,  such as metals in soils, may have
published background levels that can be applied to the
site locally.  Consult the following published data sources:

  • Background  sample  results  from other  nearby
    CERCLA site investigations
  • Local surveys by other Federal or State  agencies
    (e.g.,   U.S.  Geological  Survey   (USGS),  Soil
    Conservation Service (SCS))
  • University studies (e.g., graduate theses)
  • Tables  or  databases  with  natural  concentration
    ranges and averages in local or regional soils 1

Note that in many cases published information may be
inappropriate.  Published  data  may not  account for
regional variations or unique site-specific characteristics.1
Background levels may vary  with  regional and local
geology (e.g., ore veins, soils with naturally high metals
content).  It is difficult to demonstrate comparability
using published  data  because  of  the  difficulty of
duplicating sample method and analysis. To be similar,
published  or existing data should be generated under
quality assurance/quality  control (QA/QC) measures
equivalent to EPA requirements for release  samples.
Published data may be useful when selecting  background
sampling locations. If published data are used, multiple
sources of information help to support a  comparison
determination. The use of background level  data without
sampling (e.g., published data) may be acceptable for SI
or HRS scoring activities. The analytical package for the
published data should be obtained whenever possible. *
Background Sample Selection Considerations

Collect at least one background sample per pathway or
medium collected  outside  the area  believed  to be
influenced by the site. The activities of the investigation
team  should  not   introduce  any   non-attributable
contaminants  to  a  release  or  background  sample.
Sampling methodology can minimise this error.

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            Smart Sampling Example:
                Advantages of CIS

   For ground water contamination with multiple
   sources or very large areas of contamination,
   computer-based Geographic Information
   Systems (CIS) are often used to store and
   manage large quantities of water quality data,
   as well as hydrogeologic and geographic data
   and Potentially Responsible Party (PRP)
   information.  The advantage of a GIS over a
   standard database management system is the
   ability to relate data spatially.   Sample data In
   the GIS may contain historical background
   concentrations or aid In the selection of
   background sampling locations. In conjunction
   with GIS, use existing data from CERCLA sites.
It is often necessary to collect more than one background
sample.   The  location and  number  of background
samples depend upon:

  • Hazardous substances present  at  the  site  and
    expected concentrations
  • Availability and quality of existing information and
    analytical data
  • Objectives of the investigation
  • Site hypotheses to be tested
  • Media variability
  • Size of the site, number, and type of sources
  • Pathway-specific  considerations   (e.g.,  geologic
    formations, types of surface water bodies)
  • Other potential sources  of  contamination  in  the
    vicinity of the site 2

The number of background samples collected may also
depend upon the  type  of investigation performed.  At
times,  a  contaminated background  sample can be
compared with a release sample to demonstrate that the
site under investigation contributes at least part of the
contamination in the release sample (refer to chapter 4
of the  Guidance for Performing Site Inspections Under
CERCLA, for more information).

In general, the highest background sample concentration
can be used as a background  level.  In a non-industrial
area, average background concentrations may be  used
when sufficient background samples are collected in a
relatively homogeneous environment and there  are no
alternative sources of contamination nearby.  Qualified
analytical  data may also be used  for background  level
determination  (refer  to   Using   Qualified  Data  to
Document an Observed Release, 1994, OSWER Directive
9285.7-14FS, for more information).
In all evaluations, release and background samples must
be similar for comparison. In some situations, collection
of a comparable background sample is not possible (e.g.,
when there  is  no surface water sample similar to an
isolated pond,  or when a surface water body originates
from a spring).2 If background sampling is not possible,
substitute published  data, as available.
   Exhibit 3:      Examples of Factors Affecting
                 Comparability

     • Filtered versus unfiltered aqueous samples,
       including preservative added before or after
       filtering
     • Depth of the ground water sample (i.e.,
       screened interval). Note: Data may not be
       available for household wells
     • Density of contaminants (floater or sinker)
     • Geologic strata, sorptive capacities, and soil
       types
     • Plants that bioaccumulate certain substances
       (consider cover vegetation types and density
       between surface soil sample locations)
     • Factors within a water body
             thermal or chemical stratification
             sediments versus aqueous samples
             coarse grain sediments in riffle or
             scouring zones versus  fine grain
             sediments in depositional zones
             mixing zones
     • Age,  species, and gender (tissue samples and
       portions analyzed)
     • Date, time, and weather conditions
     • Sample handling procedures'1*
Factors  which  determine  sample  similarity  include
location,  type,  depth,  medium,  sampling  method,
preservation, handling, timing,  and weather conditions
during sampling (see exhibit 3). Variability introduced by
sampling methods can  be  much greater than  that
introduced  by  the  analytical  laboratory.   Consider
variability  factors  for  each  HRS  pathway  under
investigation.  The following are specific considerations
when  selecting background samples  for each  HRS
pathway.
 Ground Water Pathway

 A direct observation of a release to ground water can be
 documented if it is observed or known that a hazardous
 substance has been deposited, or the source lies below
 the water table of the aquifer of concern (e.g., injection
 well, buried waste). A direct observation of a release to
 ground water does-not require establishing a background
 level, but the  presence of a hazardous substance in the

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release should be documented by manifest  data or
chemical analysis. u

When establishing an  observed release  by chemical
analysis, background samples  generally  are  needed.
Collect background samples from nearby wells that are
not  expected  to  be  influenced   by  the  source  of
contamination or by other sites.  If there are other sites
or potential local sources of ground water contamination,
collect additional background samples, where possible, to
differentiate their contribution from that of the site under
investigation  (refer to the Guidance for Performing Site
Inspections Under CERCLA, for more information).

Similarity of Aquifers

Where possible, aqueous release and background samples
should be collected during the same sampling event but
must  be collected  from comparable zones in the same
aquifer.    Interconnected  aquifers  should  not  be
considered as one  aquifer when comparing samples  for
an  observed release.    When  collecting  background
samples, it is preferable not  to use samples from a well
screened in two or more aquifers.2

Evaluate aquifer characteristics before selecting wells for
sampling, especially in areas  of complex or  variable
geology. Be  aware of the existence of  mines, faults, or
other  aquifer  intrusions which may  affect  sample
representativeness.   (Note:  Section 7.1 of the  Hazard
Ranking System  Guidance  Manual,  1992,  OSWER
Directive  9345.1-07,  provides  detailed  guidance  on
determining aquifers and aquifer boundaries.)

Note  information on ground water flow direction if it is
known or can be easily determined. This information
may  also  be  useful   in  selecting monitoring well
installation locations for Expanded Site Inspection (ESI)
and   Remedial  Investigation  (RI)  work.    Obtain
information on flow direction by using piezometers, by
comparing static water levels in existing wells in the same
aquifer, and by using data from published reports.  The
well used for background sampling should be out of the
influence of the site.2

Comparability of Wells

Samples  from  any  two  wells can  be  considered
comparable if both are collected from the same aquifer
and if the sample preparation is the same  (i.e., compare
filtered release samples to filtered background samples,
and unfiltered release samples to unfiltered background
samples). Ideally, well completion techniques and usage
of background wells should be similar to those of the
well under investigation. It is best if sample methodology
is  the same  for  both release  and background wells.
Sampled wells generally should be screened at similar
zones within the  same aquifer, depending on the site
hydrogeologic setting, because different depths may have
different  contaminant  levels  and  water   chemistry.
Measure depth as elevation relative to a reference (e.g.,
mean sea level) instead of below ground surface for data
consistency.  Where possible, duplicate purge parameters
and method, sampling method, and sampling equipment
for all well  samples.  Sample release and background
samples on the same day, if possible, but not more than
three days apart.2

In cases where a background well is not available, sample
a spring before it reaches the surface by inserting a pipe
or well point near the  location  where ground water
discharges at the spring.2 Thoroughly document this type
of sampling in a field logbook. Sampling data may  be
supplemented with applicable  published data.  Springs
may  be  used for  background  sampling of  surficial
aquifers only.

Surface Water Pathway

Direct observation of a release to surface water may be
documented if material containing a hazardous substance
is seen entering surface water; is known to have entered
surface water through direct deposition; or is present in
a source which is in contact with surface water through
flooding. Direct observation of a release to surface water
eliminates the need for background  sampling, but the
presence of a hazardous substance in the release should
be documented analytically.  No background  sample is
required when sampling an effluent discharge from the
site into surface water, because the effluent is considered
a direct observation.

In non-tidal surface water bodies, sample downstream to
upstream. Background sediment samples should be from
a location  comparable to that of the release samples
(e.g., fine sediments from quiescent zones).2  Sediment
samples are generally preferred over aqueous samples  for
evaluation   of  the  surface   water  pathway  because
sediments are more likely to retain  contaminants.  In
general, aqueous samples might represent current release
conditions,  whereas sediment samples might  exhibit
historical release conditions.

Background  tissue samples  from  essentially   sessile,
benthic organisms (e.g., sponges, oysters) can be used in
support of similar (same  species) release tissue samples.
Individuals  selected  for  background  tissue sampling
should be  the  same gender and  approximate age,
wherever possible, of those selected for release tissue
sampling.2

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Special Considerations for Tidal Water Bodies

Determine the need to collect aqueous and sediment
samples in cases where the surface water body is tidally
influenced. One approach for background sampling is to
collect outside of the zone of tidal influence (this can be
gauged by the level of the highest tide). Beware of tidal
flow picking up additional sources upstream.  Consider
the effect of  the  tides on  contaminant concentration
(upstream concentrations  would be highest during the
rising tide and lowest at falling tide). Consider collecting
release and background samples at the same tidal level.1

Comparability of Water Bodies

Collect release and background samples from the same
type  of  water  body.   (Use flow  characteristics  to
determine  similar water   bodies.)   For  example,  a
background sample from a small tributary usually is not
comparable to a release sample from a river.  Consider
physical and  chemical  properties  of the surface water,
such as  lack  of mixing, in large, slow-flow segments of
rivers, physical  transport  mechanisms, and biological
influences.    Where  possible,   collect   release   and
background samples  during the same time  period, since
thermal stratification and salt/freshwater  stratification
vary with the time of year.  Consider the thermoclines of
a pond  or lake or measure them in the field prior to
sampling.u

Simple surface water pathway sampling generally consists
of a minimum of  one Probable Point of  Entry (PPE)
release sample and one upstream background sample. If
the surface water pathway has multiple PPEs, multiple
background samples may  be needed.  The number of
background samples collected depends on the complexity
of the path of the surface  water body.  The presence of
multiple  tributaries  upstream with  multiple potential
sources requires multiple background samples because of
the potential  contribution of contamination from other
off-site sources.1-2

For  ponds and lakes, background samples  may  be
collected near the inflow to the water body if it is not
influenced by the source.  A pond near the site may be
selected for background sampling if it exhibits similar
physical characteristics to the pond on site.  For  large
ponds and lakes, background samples may be collected
from  the water body itself but as far away as possible
from  the influence  of the PPE  and other potential
sources. 1

Air Pathway

Direct observation of release to the air pathway can be
documented in two ways:  a release containing hazardous
substances is seen entering the atmosphere directly (e.g.,
visually  observing dust blowing  off  a pile known to
contain hazardous substances), or an adverse effect is
demonstrated (e.g., a documented health effect from a
reaction of incompatible substances). Background levels
need not be established when an observed release by
direct observation is documented.

Weather conditions are critical for evaluating the air
pathway. Throughout the sampling period, determine the
predominant wind direction and speed. Consider lack of
air movement, effects of low temperatures, existence of
flat,  open  terrain, and  any  atmospheric instability.
Perform background sampling upwind  of site sources,
although cross-wind samples may be acceptable. Always
consider multiple samples for this pathway and collect
them  from  the  same  height and at the same time.
(Samples from great heights such as rooftops generally
are not useful because they do  not represent target
conditions; very low heights are subject  to  potential
interference  from  particulates  introduced  by  field
activities.) Dust, wipe, soil, and soil gas samples are not
acceptable for background sampling in the air pathway,
but these types of samples may be used, along with field
air  monitoring   equipment,  to  select  release   and
background sample locations. Always sample release and
background   concurrently.    A  minimum   12-hour
monitoring period is recommended for sampling the air
pathway,  particularly  during  hot  and  dry  weather
conditions. u

Wind roses may be used to determine predominant wind
direction, or to document changes in wind direction; this
is important when selecting sample stations.' The "rose'
diagrams consist of bars on a compass face indicating the
frequency of each wind direction during the selected time
period, as well as the average high wind  speed for the
period.   If  wind  roses  are  utilized, determine  the
elevation for which the wind rose was calculated; this
elevation should  be representative of target exposure.
Weather stations and airports may provide information
on  local wind direction at ground level and at various
elevations.

Soil Exposure Pathway

There is no direct observation of contamination in the
soil exposure pathway.  Establishing background levels
for this pathway  can  be  difficult,  particularly if the
hazardous substances attributed to the site are naturally
occurring substances.  Where possible, collect on-site
background soil samples from surficial soils not likely to
be  affected  by the source. Collect  off-site background
soil samples from shallow soils which ideally should not
be  affected by  other  sources  and  sites  in  the  area.
However,   if   there   are  alternative    sources  of
contamination  in  the  area, background levels should
account for these contributions.  When possible, sample
release and background samples on the same day, or not
more  than three days apart.  (See Highlight 9-1 of the

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HRS Guidance Manual for information on background
samples  for  non-soil  sources  in the  soil  exposure
pathway).

Carefully document location, depth, and appearance of
all soil samples. If depths  and thicknesses of soil strata
vary with location, ensure  that release and background
samples  are  from a  similar stratum  and  soil type.
Samples  should have similar  texture, color,  and grain
size. J   During an SI, grab  samples (as opposed to
composite)   are  preferred   for  determining   soil
contamination. Obtain  the background sample from an
undisturbed,  unfilled   area,   because  fill  may have
contaminants which are not representative of background
conditions.   If a site  is  located on fill,  obtain  the
background samples from a similarly filled area  (where
the fill is not  considered one  of the areas of observed
contamination at the site).1

Select more than one background sample and location
for  the  soil   exposure pathway.   Do  not  collect
background soil samples from  a drainage channel which
receives water  from off site. l  Where possible, collect
background samples from  a higher elevation than  the
sources to avoid the effect of potential surface drainage.
Avoid background sample  locations that are  subject to
airborne  contamination  from the site or other sources.1J

Determining Background Levels in Industrial, Mining,
and Radioactive Areas

Industrial areas pose a special challenge to determining
background levels.  Ambient conditions may  include
elevated  concentrations of  common -contaminants from
alternative sources not associated with the site.  Common
contaminants  in background samples in industrial  and
urban areas include:

   • Metals in soils (e.g., lead)
   • Trichloroethene (TCE) and perchloroethene (PCE)
    in urban aquifers
   • Organic substances in  harbor  sediments 2

In  industrial  areas,  the  investigator often  needs to
document that a release sample  is above background
sample variability. Where potential alternative  sources
exist and possibly interfere with background  or  release
samples,   assess  whether the   interference  affects
background samples and the site significantly, or whether
bias can  be determined.  Because industrial  areas are
affected by increased levels of contaminants and  greater
local variability, additional  background samples  may be
required  to establish surrounding off-site conditions.  Be
sure to collect a sufficient  number of samples between
the site and all other potential sources of contamination
in order to attribute the increase to the site.J In general,
it is inappropriate to average background samples in an
industrial area where more than  one type of industry
existed. This probably will lead to unacceptable levels of
local  variability (see Establishing Areas  of Observed
Contamination, 1994, OSWER Directive 9285.7-18FS, for
more detailed  information).

Mining areas,  like industrial areas, pose a challenge to
determining background levels. Often the contaminants
associated  with  the  mine  are  naturally  occurring
elements.  Surface water may originate from the mine,
presenting   no  upstream   location  for   background
sampling.  Surface water may pass through the mined
watershed; its  nearest upstream location away from the
influence of the  site may be  in a different geologic
formation,  with different water  chemistry,  producing
uncertainty about comparability. Mines are often located
in areas with aquifers that  are highly  fractured or
influenced by mine drainage tunnels. It is difficult to find
undisturbed  areas in which to locate ground water wells.
Because it may be difficult  to determine background
levels in mining areas, it is preferable to determine an
observed release by direct observation (e.g., evidence of
mining below  the water table of the aquifer of concern,
tailings observed  in  surface water).  Mine  tailings
generally have a high concentration of minerals and are
considered waste; collecting background samples is not
necessary  if  tailings are  analyzed  and  the  mineral
concentrations are shown to  be  elevated well beyond
what might be expected under natural conditions.

When surface  water originates in  the source or when no
similar upstream location exists, select a water body with
similar physical characteristics (e.g., a similar stream on
the other side  of a mined hill) for background sampling.
The similar water body should not be directly affected by
the site. Release concentrations may be so significantly
elevated (this  is common with large-scale  mining sites)
that published data may provide  a more  reasonable
background   level   for  comparison.     Establishing
background  conditions  at  mining  sites  should be
addressed on a site-by-site basis.

To sample sites with radioactive wastes, follow sampling
strategies similar to those for other hazardous substances.
Criteria  to  establish  an  observed release  through
chemical analysis for radioactive substances are available
for the following three groups:

   •  Radionuclides  that occur naturally, or  ubiquitous
     man-made radionudides
   •  Non-ubiquitous man-made radionudides
   •  External  gamma radiation (soil exposure  pathway
  ,   only)

Some portion of the release sample concentration must
be  attributable to the site.   For each group,  compare
release  concentrations  against  known  background
radionuclide   concentrations    or   against   sample
quantitation limits for a sample medium. Section 4.9.4 of
the  Guidance for Performing Site Inspections  Under

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CERCLA  provides details on establishing an observed
release for each group.

Summary

Collect samples to improve documentation for factors
that significantly affect HRS evaluation. If demonstrating
a release or establishing actual contamination is critical
to evaluating a site, do not limit background or QA/QC
samples unduly because  of budgetary considerations
—collecting these samples  may prevent having to return
to the site. Thorough documentation of the locations of
the background samples and potential alternative sources
is  necessary to  assess the  adequacy of the  background
levels and to evaluate release and attribution.  Evaluate
the benefits of sampling at specific locations and assess
the validity of existing analytical data. Meet SI objectives
while conserving  Superfund resources  when  feasible.
Direct observation  of  a release  does  not  require
background sampling if  detectable  concentrations of
hazardous substances are  documented to be present in
the source.  Background samples may not be  necessary
for certain man-made compounds.

To establish background  levels by  chemical  analysis,
thoroughly review on-site and off-site sources and their
locations.  Collect background and release samples from
similar locations and media.  Ground water samples are
similar when they come from the same zone within an
aquifer and undergo similar sample preparation. Collect
background samples for surface water upstream of the
PPE.   Additional site reconnaissance and review are
often  needed to select sampling locations  in industrial
and mining areas and  at complex sites.
References

1.  U.S.  Environmental  Protection  Agency,  1992.
    Hazard Ranking System Guidance Manual. Office of
    Solid Waste and Emergency Response.  Directive
    9345.1-07.

2.  U.S.  Environmental  Protection  Agency,  1992.
    Guidance for  Performing Site Inspections Under
    CERCLA.  Office of Solid Waste and Emergency
    Response.  Directive 9345.1-05.

3.  U.S.  Environmental Protection Agency, Hazard
    Ranking System, Final Rule.  40 CFR Part 300.

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                        Additional copies can be obtained from:

                     National Technical Information Service (NTIS)
                              Department of Commerce
                                5285 Port Royal Road
                                Springfield, VA 22161
                                   (703) 487-4650
                                 Order # 94-963313
United States
Environmental Protection Agency
5204G
Washington, DC 20460

$300 Penalty for Private Use

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                        United States
                        Environmental Protection
                        Agency
 Office of
 Solid Waste and
 Emergency Response
Directive 9285.7-20FS
PB94-963314
EPA/540/F-94/031
October 1994
    &EPA       Establishing  an   Observed  Release
  Office of Emergency and Remedial Response
  Hazardous Site Evaluation Division (5204G)
 •MM^^MMMHB

Abstract
DRAFT
                        Quick Reference Fact Sheet
The Hazard Ranking System (HRS) establishes criteria for documenting an observed release and observed contamination.
This fact sheet describes an observed release and the data required to substantiate it for National Priorities List (NPL)
rule-making purposes.  This fact sheet further describes the process documenting an observed release and emphasizes
strategic, efficient sampling.
Introduction

Three categories of sampling generally are performed
during a Site Inspection (SI):

  • Source  sampling  to  establish  the  presence of
    hazardous substances at a site
  • Sampling in the media of concern to establish an
    observed  release, with  background   sampling
    corresponding to the source to establish attribution
  • Quality   Assurance/Quality  Control  (QA/QC)
    sampling (e.g., field blanks) to ensure data integrity

This fact  sheet addresses  the  second  category of
sampling, although each category is dependent upon the
others for site assessment.

Determining an Observed Release

An observed release is  evidence that contaminants have
migrated from a site to a pathway or medium. Ground
water, surface water, and  air constitute the migration
pathways for observed  releases.  The Hazard Ranking
System (HRS) establishes general criteria to document
an  observed release:   there must be evidence of a
hazardous  substance in the medium of concern at a
concentration significantly above  the background level,
and the release and the hazardous substance must be at
least  partially   attributable  to   the   site   under
investigation.1^  In contrast, the soil exposure pathway is
evaluated  for observed contamination,  where  targets
(human   populations,  resources,   and   sensitive
environments)  may  come into  direct  contact with
contaminants.   For more  information on  the soil
exposure pathway, refer to the fact  sheet Establishing
   Areas  of Observed  Contamination,  1994,  OSWER
   Directive 9285.7-18FS.

   An observed release  can be  determined either by
   chemical analysis of samples, or by directly observing the
   release of the hazardous substance (to be documented)
   into the medium of concern (see figure 1).

   Documenting an observed release by chemical analysis
   cannot be accomplished without determining background
   level and attribution. Determine background level by
   sampling or by using other acceptable information such
   as published or existing sample data.  For example, a
   ground water well or surface water intake with historical
   monitoring data may show a change in contaminant levels
   over time.  If the change is attributable to the site or
   source,  the  data may serve both as background and
   release levels.  Attribution requires documentation that
   the hazardous substance detected in  a medium resulted
   from site activities.  Background samples or existing data
   should be as similar as  possible to the release samples
   for comparison.2 For more information on establishing
   background  levels,  refer to the fact sheet  Establishing
   Background Levels, 1994, OSWER Directive 9285.7-19FS.

   Documenting an observed release is a prerequisite for
   evaluating actual  contamination  at targets.   Actual
   contamination is evidence that targets have  contact with
   the hazardous substance(s) resulting from an observed
   release.  The level of actual contamination is determined
   by comparing the release sample concentration to health-
   based or ecological benchmark  values, where available.
   Level I  contamination  is at or above media-specific
   benchmarks; level n  is a  concentration less  than
   benchmark  values.    Note  that  the  detection  of
   contamination at  targets  is not in  itself sufficient to

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                          Figure 1:  Flowchart for Establishing an Observed Release
                          Wa» the material
                            containing
                       a hazardous substance
                      observed entering or aeen
                            existing in
                         the environmental
                             mBdium?
                                        Is the concentration of a
                                        hazardous substance in
                                          the release sample
                                          significantly above
                                            background?
                           a the hazardo
                            substance
                           attributable to
                             the site?
                                             No observed
                                               release
                                              •t the site
                                                                                         Is a portion of
                                                                                         the significant
                                                                                           increase
                                                                                         attributable to
                                                                                           me site?
                                                                                       Observed release
5
YES
r
Observed release
established by
direct observation
* Not applicable to ground water plume sites with unknown sources

 Figure adapted from reference 2 (p. 56)
establish an observed release or actual contamination.2
Samples can be  strategically  collected to establish an
observed release and  to  include  one or more targets
(dual  purpose   sampling).     Analytical  data  with
appropriate  and  adequate  quality  assurance/quality
control (QA/QC)  are needed, since benchmarks are
expressed in concentration units.

Resource Considerations

The SI is  a  limited-scope biased sampling event, and
selecting strategic  sampling locations is critical to its
success.  Evaluate  the benefits of sampling at specific
locations.  Use available data when possible to meet SI
objectives and conserve resources (see exhibit 1).
Observed Release by Direct Observation

To establish an observed release by direct observation, a
hazardous substance must be observed or known to have
been released into the medium of concern. Use existing
                                             analytical data or other references, such as manifests, to
                                             document that the hazardous substance is present or
                                             known to  have  been released.2   See exhibit  2 for
                                             examples of an observed release by direct observation.

                                             For the ground water pathway,  an observed release by
                                             direct observation may be documented with information
                                             that  hazardous materials have come to be  located or
                                             deposited in the aquifer of concern.2

                                             For  the  surface  water  pathway, direct observation to
                                             establish an observed release can be documented by:

                                               •  Documented hazardous substances seen entering the
                                                  water  body  through migration or known to have
                                                  entered through direct deposition
                                               •  Flooding  of a  source area  so  that  hazardous
                                                  substances come in direct contact with the water
                                               •  Documented  adverse  effects  (e.g.,  fish  kill)
                                                  associated with the release of a hazardous substancg
                                                  to  surface water.   Note  that inference  require^
                                                  extensive documentation and verified attribution.2

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     Exhibit 1:     Questions to Consider when Determining the Need for Sampling

       1. Is then an imminent or current threat to human health or the environment? Is a removal action
       warranted? Sample at targets if human or environmental exposure to contaminants is suspected.  Sample
       for public health concerns, where possible.
       2. Does the pathway critically affect the site Hazard Ranking System  (HRS) score (^ 28.50)? If yes, must
       an observed release be documented for that pathway to achieve that site score? If no, evaluating the
       pathway for potential contamination may be sufficient (particularly for less critical pathways).
       3.  What are the constraints of the pathway? Are targets nearby? Each HRS pathway has certain criteria
       for determining and limiting target distance with respect to contaminants.  For example, for  the soil
       exposure pathway, contamination must be documented within a zero to 2 foot depth of the surface, and
       contamination must be on the property and within 200 feet of targets. For the surface water pathway,
       the surface water body must be within two overland miles  of the site or source.2 If release  samples
       cannot meet the pathway constraints, do not collect samples.
       4.  What an the objectives of the SI?  Table 4-7 in Guidance for Performing Site Inspections Under
       CERCLA provides guidelines on the number of samples recommended for a focused, expanded, or single
       SI as part of an observed release sampling strategy.1
For  an observed release by  direct observation from
flooded contaminated soils to surface water, the presence
of a hazardous substance significantly above background
prior to flooding must be demonstrated.1  Historical data
may be sufficient to document flood levels, the presence
of a hazardous substance, and its  direct contact with
flooded waters.

For  the  air  pathway,  direct  observation  may  be
established by  demonstrating adverse effects from a
release.2
Observed Release by Chemical Analysis

An observed release can be documented when samples
from the  media of  concern  exhibit  contamination
significantly   above   background   levels,   and  the
contaminants  are attributable to the source.   Since
concentrations of contaminants usually  decrease with
distance from a  source, sampling near to  sources will
better establish an observed release and attribution.1  At
minimnm) one validated sample and  a background level
are required to document a release, even  if earlier or
later sampling fails to show a release.  Varying results
could  be  due  in  part  to intermittent  releases.2
Background level determination usually is required to
attribute an observed release to the site.

To document an observed release by chemical analysis,
the   following  criteria   must  be  met  (except  for
radionuclides, which are  discussed later  in this fact
sheet):

   1.      The release of a hazardous substance  must be
          at least partially attributable to a source at the
          site. (Note:   This  does not  apply to  ground
          water plume sites with unknown sources.)
 2.     The release sample  concentration must  be
        greater  than or  equal  to the  appropriate
        detection limit (e.g., sample quantitation limit
        [SQL]).U

 3.     If the  background level is below its detection
        limit, the release sample concentration must be
        greater  than or  equal to the  background
        detection limit, or, if the background level is
        greater than or equal to its detection limit,  the
        release sample concentration must be at least
        three times the background concentration.2

 4.     The detection limits must be calculated  or
         determined properly. The detection limit used
         for comparison often depends on the source of
         the analytical data. The SQL is the preferred
         HRS measure, but other limits such as those
         provided by the Contract Laboratory Program
         (CLP) may be used.2 Note that detection limits
         may be different for release and background
         samples.

Observed release sampling issues  vary according to the
medium, or pathway. These issues include temporal  and
spatial variation, hazardous  substances  present,   and
documentation of location and collection conditions. The
surface  water  pathway  may  use  aqueous, effluent,
sediment,  and  tissue samples  from sessile, benthic
organisms to document an observed release.  The other
pathways  generally  are  more limited  (e.g., aqueous
samples for ground water, soil samples for soil exposure,
and air samples for the air pathway).  Establishing an
observed release in the ground water pathway could be
further complicated by uncertainties about ground water
flow  direction,  and  the  resultant  uncertainty about
background and attribution.

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     Exhibit 2:     Examples of an Observed
                  Release by Direct
                  Observation

       •  Ground water pathway-Hazardous
         substances placed into an old quarry
         where the water table has been
         reestablished above the level of the
         deposited materials.
       •  Surface water pathway—An
         impoundment leachate seep seen
         entering a stream. (Collect a sample
         from the leachate to document
         hazardous substances.) Also, effluent
         known to contain hazardous substances
         (through manifests) seen entering a
         surface water body.
       •  Air pathway—A field logbook entry and
         photodocumentation of a dust cloud
         originating from a tailings pile. A
         sample of the fine particulate matter
         from the pile showing the presence of
         hazardous substances will verify the
         release. u
Ground Water Pathway

For the ground water pathway, certain types of wells,
including monitoring, irrigation, or drinking water wells,
may be used to establish an observed release, although
the same well may  not necessarily serve  to document
actual contamination of targets. For a target population,
actual  contamination should  be documented  using a
drinking water well. To establish an observed release,
sample the well(s) closest to the contamination source,
where  possible.  Select background well(s) outside the
influence of a source and in the same aquifer being
evaluated.     Either  cross-gradient   or   upgradient
background sample -locations  are preferred  when flow
gradient information is available.  (Ground  water flow
gradient is not required for HRS purposes.) Be cautious
about using wells that are close to the site as background,
because some sources (e.g., landfills and impoundments)
interfere with natural ground water flow. Pumping also
may affect ground water direction and plume movement:
If available, pumping  rates of nearby wells (including
those  sampled)  may serve  as a  useful  source  of
information for addressing  both sample comparability
and contaminant effect.

Consider characteristics of suspected  contaminants in
water  when  selecting  sample  locations  and  depths.
Contaminants in water may not be evenly dispersed. Oils
and organic substances lighter  than water  (light non-
aqueous phase liquids [LNAPLs]) tend to float on top of
the water table. Contaminants heavier than water (dense
non-aqueous phase liquids [DNAPLs]) sink to the bottom
of the water column. IJ
     Smart Sampling Example:  Using Springs
     to Qather Ground Water Data

     Experience at several sites indicates that
     springs are an underutilized  source of
     ground water quality data, which are usually
     obtained from monitoring wells.  Springs are
     common, occur in most geological settings,
     and are found at, or near, many hazardous
     waste sites.   They require no installation or
     purging, and may be used to gather rapid
     screening data upon site discovery and/or
     later as part of an established sampling or
     monitoring program. The spring sample
     must be documented as ground water rather
     than surface water.  When properly
     documented, spring sampling successfully
     has identified surficial aquifer contamination
     when well sampling did not.  It also has
     located reaches of streams into which
     contaminated ground water plumes
     discharge. Consider using springs as
     surficial aquifer sampling points for
     documenting either a background level or
     an observed release.
Surface Water Pathway

A minimum of two samples  (aqueous or sediment)
generally is required for documenting a release in the
surface water pathway:  a background sample slightly
upstream  of the  Probable  Point  of  Entry (PPE) for
contaminants  from  the  site  or source,  and a release
sample at or slightly downstream of the PPE. Beware of
tidal  flow  picking  up  additional sources  upstream.
Exceptions to the two sample minimum are when the
surface water body  originates at the  site (no upstream
background exists) or when multiple PPEs exist. In the
first case, one sample may be sufficient to document a
release.  In the  second case, it  may be  advisable  to
sample at  or downstream of each PPE to establish  an
observed release; similar background sample(s) should be
inciuded.u

Proper sampling methods  and sample  handling  are
critical for documenting an observed release, particularly
for the surface water pathway. Aqueous samples may be
used to document  current releases to  a surface water
body. Collect the downstream sample first, and aqueous'
samples before sediments, to avoid the introduction of
any contaminants not associated with the site or medium.

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Minimize aeration of a sample to prevent reducing the
concentration  of contaminants such as volatile organic
chemicals.

Consider seasonal and other potential variations such as
irrigation  and  flooding when sampling  in this pathway.
Deep,  slow-moving surface  water bodies often exhibit
some chemical or thermal stratification.  Stratification
also occurs where two streams converge. The absorption
or dilution of substances is affected by stream movement,
and depositional conditions vary within the riffles or close
to stream edges.2

Sediment  samples  may be used to document historical
releases to the water body. Ideally, the characteristics of
the suspected contaminant(s) should be known to select
the best sample medium, location, and sampling method.
Grain  size,  organic content, and structure can affect
adsorbance of substances to sediments.  For example,
trichloroethylene  (TCE)  adsorbs to certain particles,
which may bias a sample. 2  Sediments  are scoured and
deposited in bends of streams and other flowing surface
water bodies.  Sample from  like areas (e.g., inside bend
deposition areas) for comparability.

Distinguish  sediments  from  soils,  especially  when
sampling along the  edge  of a water body.  Note that in
arid or semiarid locations (less than 20 inches mean
annual  precipitation), "sediments" include areas with
intermittently  flowing waters  as  well as  contiguous
intermittently flowing ditches.  Contamination hi  these
areas should be evaluated in the surface water pathway.3

Tissue  sampling poses  challenges - for  comparability
because of differences between members of the  same
species, differences between species, variations within a
study   population,   species   mobility,   and   tissue
differentiation.  The target sample species should be
examined for type of organism, approximate age, gender,
size of population,  migratory nature, and seasonal,
feeding,  spawning, • or  other  periodic activities  that
influence  concentration  of  substances  within  the
organism.2 Tissue samples can be used to determine an
observed release only under limited circumstances; they
are more readily used to document actual contamination.
It is prudent to collect tissue samples in concert  with
other sampling activities when documenting an observed
release.

For tissue sampling, document both the rationale for the
tissue  selection,  and  the  accuracy of  measurement.
Edible  tissues from sessile,  benthic  organisms are
preferred for  HRS evaluation.  (Non-sessile  benthic
organisms, finfish,  amphibians, and reptiles generally
should not be  used.)
Air Pathway

It  is important to consider  temporal variability in air
sampling   because   large   variations  in  substance
concentration  can  occur  over  a  very  short time.
Emissions characteristics depend upon topography and
changeable   atmospheric   conditions,   including
temperature,  pressure,  wind  speed  and  direction,
precipitation, and atmospheric stability.

Monitoring  wind  direction is prudent  to  document
migration of hazardous substances  from the  source.
Wind roses, which detail the percentage of predominant
wind  direction, should be developed for the sampling
period to document shifts in wind direction.2

For  the  air pathway,  an  air  sample may be  used to
document  both  an   observed  release  and  actual
contamination of targets within a certain radius from the
source. (In contrast, the ground water pathway requires
sampling  at the target;  the  surface water  pathway
requires  sampling at or beyond the  target to establish
actual contamination.)

An observed release by chemical analysis is not easy to
establish for the air pathway because of the difficulty of
obtaining comparable and verifiable samples. The HRS
evaluates outdoor ambient air conditions only; indoor air
samples are not evaluated for this pathway.2
Partial Attribution and Multiple Source Sites

Sources of contamination other than those found at the
site  under  investigation are  often present.   Where
attribution is questionable, sampling  should  produce
analytical data demonstrating that the contamination is at
least partially attributable to the site. Contributions from
sites sometimes can be isolated by identifying hazardous
substances unique to the site under investigation. This
may  require special   analytical  services  and  close
evaluation of data. Knowledge of the nearby  facilities'
disposal  practices and wastes is helpful.'

Attribution may be  established through  the use  of
manifests, labels, records, oral or written statements, or
other information regarding hazardous substances present
at the site or at alternative sources.  If these references
confirm the presence of a hazardous substance in release
samples, attribution generally can be established even if
specific  sources  where the substance was  deposited
cannot be documented.2

Establishing  background  levels  is  important  when
attributing  hazardous  substances  to varied   sources.
Background and release sample data should be from the
same  medium using  similar sampling  and analytical
methods. Background samples should be collected from

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outside  the  influence of contamination from  the  site
under investigation,  but do  not have to  be  free of
contamination.   The data need only  support  that the
release  sample concentration is beyond  a reasonable
background level. Thoroughly review and document the
location  of  potential alternative sources  so that  the
appropriate  background sampling locations  can  be
selected. Many hazardous substances may be widespread
in the vicinity of the site. Substances may originate from
non-point  sources  such  as   pesticides   and  lead.
Background levels  for  ubiquitous substances  should
account for local variability, several  samples  may  be
required to establish this variability. *

Obtain   sufficient  samples  from  the  site   under
investigation and from other known potential sources (or
other adjacent sites)  to demonstrate that an increase in
contaminant levels is attributable to the site. Additional
information beyond analytical samples may be required
if the other sites release intermittently.  To attribute
contamination sufficiently, collect the following  data:

  • Concentration gradients (e.g., establish an observed
    release and attribution with samples from  multiple
    wells or  a series of samples between the  site  and
    alternative sources)
  • Flow gradients  and other information about the
    media of concern
  • Data that associate  the site with a unique substance
    or unique ratios of  different substances 2

Complex  factors  affecting  attribution   (e.g.,   soil
contamination  in  an   industrial  area)  may  require
conducting an expanded SI.  In many  cases, attribution
concerns may be addressed by  fully characterizing all
sources  at a site and those of neighboring sites.1

To establish attribution for the ground water pathway,
sample wells located between site sources and alternative
sources.  Three wells generally are needed to define flow
direction and to verify the source versus an alternative
source(s). For surface water, a release sample may be
collected downstream of or at the confluence.  Sample
background  and attribution along  each  tributary  if
multiple sources are  located upstream.2
Transformation Products

Transformation  products are substances found when a
hazardous substance is changed in the environment by
physical, chemical,  or  biological  processes.    Most
transformation products at hazardous waste sites are the
result of degradation.2

An observed release'for transformation products must be
documented by chemical analysis and the transformation
product must be a hazardous substance.2
Document the presence of a transformation product in a
release sample at levels significantly above background
level  to  attribute  the  parent substance(s)  and  the
transformation  product to  the  site.   The  following
references may be  useful for  documenting the parent
substance and transformation product relationship:

   • Site-specific studies on the transformation process by
    qualified   research  organizations   (e.g.,   U.S.
    Government  agencies, universities)
   • Technical reports  on transformation  from EPA's
    Office of Research and Development
   • Databases containing EPA-reviewed information
   • Articles from peer-reviewed journals
   • Textbooks  on  soil, environmental  microbiology,
    biotechnology, and biotreatment processes and their
    effectiveness  2

For determining an observed release,  conditions at the
site  must  be  conducive  to,  or  must  not  impede,
transformation, and at least one source must be able to
release the substance to the pathway.2
      Smart Sampling Example:  Minimizing
      Investigation Derived Wastes (IDW)

      Solvents, equipment, and other materials
      used in site investigation and cleanup may
      themselves end up as hazardous waste.
      Disposal of IDW at an approved facility
      increases site costs and adds to the overall
      waste disposal burden.  Take  precautions to
      minimize waste generated on  site. Solvents
      should be recycled rather than incinerated,
      whenever feasible. In many instances,
      drums may be cleaned and reconditioned
      instead of sent to a landfill. A series of
      treatment steps may reduce the final volume
      of hazardous waste for disposal.  Consider
      pollution prevention when planning response
      actions.
 Radionuclide Sites

 The criteria for  documenting an observed release by
 direct  observation apply to radionuclides.  Table 7-1 in
 the Hazard Ranking System, Final Rule provides the HRS
 factor  categories  that  are evaluated differently  when
 radionuclides are present.3

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For  documenting an  observed  release by  chemical
analysis, radionuclide sites are divided into three groups:

  1.      Radionuclides  that   exist  naturally   and
         ubiquitous radionuclides.
  2.      Man-made   radionuclides   which  are  not
         ubiquitous.
  3.      External  gamma  radiation  (for  the  soil
         exposure pathway only).

Observed releases from a combination of radionuclides
and   hazardous  wastes (mixed  waste)  should  be
documented separately.

Establishing an observed release requires:

  • Identification of the radionuclide of concern and the
    physical and chemical properties of the radionuclide
  • On-site   and  background  activities   for   that
    radionuclide
  • SQL or other detection limit for the radionuclide

For gamma radiation, measure the exposure rate  at one
meter above ground for the soil exposure pathway.

Specific requirements for establishing an observed release
for  each of the three groups of radionuclides can be
found in Section 7.1 of the Hazard Ranking System, Final
Rule.
Summary

Documenting an observed release for NFL rule-making
purposes requires evidence that the concentration of the
hazardous substance of concern significantly exceeds the
background  level.  The hazardous substance must  be
attributable at least in part to the site under investigation
(except for  ground  water  plume  sites  with  unknown
sources).   Establishing an  observed  release requires
thorough documentation.  The sampling design should
attempt to meet multiple HRS data needs with a limited
number of samples.
References

1.  U.S.  Environmental   Protection  Agency,  1992.
Guidance for Performing Site Inspections Under CERCLA.
Office  of Solid  Waste  and  Emergency  Response.
Directive 9345.1-05.

2. U.S. Environmental Protection Agency, 1992. Hazard
Ranking System Guidance Manual. Office of Solid Waste
and Emergency Response.  Directive 9345.1-07.

3.  U.S.  Environmental Protection Agency,   Hazard
Ranking System, Final Rule. 40 CFR Part 300.

-------
                                Additional copies can be obtained from:

                              National Technical Information Service (NTIS)
                                      Department of Commerce
                                        5285 Port Royal Road
                                        Springfield, VA 22161
                                           (703) 487-4650
                                         Order # 94-963314
AEPA
  United States
  Environmental Protection Agency
  5204G
  Washington, DC 20460

  $300 Penalty for Private Use

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                   United States
                   Environmental Protection
                   Agency
Office of
Solid Waste and
Emergency Response
Directive 9285.7-18FS
PB94-963312
EPA/540/F-94/029
October 1994
                    Establishing  Areas  of  Observed
                    Contamination
   Office of Emergency and Remedial Response
   Hazardous Site Evaluation Division (5204G)
         DRAFT
                            Quick Reference Fact Sheet
Abstract

This fact sheet addresses the use of analytical data to establish areas of observed contamination at a hazardous waste site
when evaluating the soil exposure  pathway under the Hazard Ranking System (HRS). The data may also be used to
evaluate hazardous waste quantity for some HRS source types.  The soil exposure pathway is evaluated only if observed
contamination is established.  Establishing observed contamination, defining the area of observed contamination, and
identifying areas of differing levels  of contamination are critical  in evaluating the soil exposure pathway.
Introduction

The Hazard Ranking System (HRS) establishes general
criteria to document an observed release of hazardous
substances to the migration pathways (ground water,
surface  water,  air)   and to  document  observed
contamination in the soil exposure pathway. An observed
release is evidence that contaminants have migrated away
from a site to a migration pathway. In contrast, observed
contamination  is   evidence  that   targets   (human
populations, resources, and sensitive environments) have
come into direct contact with the contaminants. Unlike
the migration pathways, the soil exposure  pathway is
evaluated based on  current, rather than historical, site
conditions. An exception occurs when a removal action
is performed under EPA oversight during or after a Site
Inspection (SI).  In such a case,  the soil  exposure
pathway could be evaluated based on conditions prior to
the removal action  (see the fact sheet The Revised
Hazard Ranking System:  Evaluating  Sites After Waste
Removals,* OSWER 9345.1-03FS, for more information
on removal actions performed during  or after  an SI).

The  HRS criteria for documenting  an observed release
and observed contamination are:  there must be evidence
of a hazardous substance in the medium of concern at a
concentration significantly  above the background level
and at or above the  appropriate detection limit, and the
         hazardous  substance  must  be  at  least   partially
         attributable to a release from the site under investigation
         (see  figure 1). (For more information  on  observed
         releases, refer to the fact sheet "Establishing an Observed
         Release," OSWER Directive 9285.7-20FS.)
         Establishing Observed Contamination

         When evaluating  the soil exposure pathway, observed
         contamination must be documented by chemical analysis
         of  samples from  contaminated  areas.   The source
         samples are compared to a background level.  Most
         samples consist of soil, but leachate, waste, sediment, and
         other  surfitial  samples  may  be  collected. '    In
         comparison, an  observed  release  in  the  migration
         pathways  may   be  documented  either  by  direct
         observation or by chemical  analysis of release samples
         compared to a background level.

         Three  criteria must be  met  in order to  document
         observed contamination by chemical analysis:

            1.     The source sample  concentration  must be
                  greater  than or  equal to  the appropriate
                  detection limit (e.g., sample quantitation limit
                  [SQL]). The detection limit must be properly
                   determined.

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                        Figure 1: Flowchart for Establishing Observed Contamination
                              I* the concentration of •
                              hazardous substance in
                                the source sample
YES
                                        NO
No ob
contam
at the

letved NO
Sit*
NO
                                                                           Is the hazardous
                                                                              substance
                                                                              Increase
                                                                             attributable
                                                                             to the site?.
                                                                                   YES
                    * Direct observation does not apply to
                          the sol I exposure pathway

                    Figure adapted from reference 2 CP   56}
                  Observed
                contamination
                established by
                       analysis
chemical
  2.     If the hazardous substance of concern is not
         detected in the background samples (or  its
         concentration is less than the detection limit),
         the  source sample  concentration  must  be
         greater than or equal to its detection limit, if
         both  detection limits  are  the  same.     If
         background levels are greater than or equal to
         the   detection  limit,  the  source  sample
         concentration must be at least three times the
         background level.  Note that  detection limits
         may be different  for source and background
         samples.

  3.     The  hazardous substance is  present  at the
         surface or is covered by no more than two feet
         of  penetrable material (except for gamma
         radiation  emitters,  which have  no depth
         restriction).J
Sampling to Meet the MRS Sampling Objective

In the soil exposure pathway, there is no  acceptable
documentation of  observed  contamination  based  on
direct observation, and the potential for contamination is
not evaluated. Consider both the types and locations of
targets when selecting sampling locations.  Establish an
area of observed contamination as dose  to  targets as
possible.   Evaluate  targets under the HRS resident
population   threat  when   an   area  of   observed
contamination lies on the site property and within 200
feet of a residence, school, day care center, or workplace.
Evaluate sensitive environments and resources in  the
resident population threat only if the area of observed
contamination  lies within site  boundaries.   Evaluate
targets beyond 200 feet but within one mile of the area
of  observed  contamination  under  the  HRS  nearby
population threat.4  Collect samples no deeper than two
feet below the surface.   Document  the  absence of  a
maintained, essentially impenetrable cover material (e.g.,
asphalt, concrete)  over  any portion  of an  area  of
observed contamination.1 Since surficial contamination is
not limited to soil, sampling of other surface media, such
as leachate or waste, should be considered.

Attribute   contamination to   a  site   by   collecting
appropriate background samples outside the influence  of
sources. Obtain source samples from locations where the'

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Exhibit 1: Background Samples for Areas of Observed Contamination
Source
Contaminated soil
Tanks/Drums filled with contaminated soil
Tanks/Drums containing liquid or solid wastes
Landfill"
Piles*
Surface Impoundment (liquid)"
Surface impoundment (sludges or backfilled)*
Other sources
Background Sample
Soil in vicinity of the site1
Same as for the soil at the site
Background is zero
Soil In vicinity of the site
Soil in vicinity of the site
Aqueous samples from vicinity of the site;
background may be zero
Soil in the vicinity of the site
Review on a site-specific basis
'See sections 5.1 and 5.2 of reference 2 for additional considerations.
Tor these source types, the Indicated sample is likely to be the most appropriate background.
Figure adapted from Highlight 9-1 of reference 2 (p. 344)
substances are suspected to have been deposited (e.g.,
contaminated soil along the flood plain of a contaminated
surface water body). 2  Exhibit 1  suggests appropriate
locations for background samples by source type.
Evaluating  Waste Quantity by  Defining  Areas  of
Observed Contamination

Identify and delineate areas of observed contamination
for the following reasons:

1.   The soil exposure pathway can be evaluated only if
    there are areas of observed  contamination.

2.   Target values are assigned based on the distance of
    targets from the area of observed contamination.

3.   Waste quantity can be calculated based on the area
    of observed contamination.

A  site  may  have more  than  one area  of observed
contamination.  Each area of observed contamination
may be  associated with its own targets.  Assign a source
hazardous waste quantity value for each area. Sum the
source hazardous waste quantity values assigned to each
area of  observed contamination  to determine the waste
quantity factor value for the soil exposure pathway.1
Some soil areas cannot be included in evaluating an area
of observed contamination.  Exclude the following sub-
areas:

   • Areas   covered  by   permanent  or  otherwise
    maintained and essentially  impenetrable  material
    (e.g., asphalt, concrete)

   • Areas  of higher  ground not influenced by  runoff
    from the site, if contamination results from runoff

   • Areas  where the types of operations at a  facility
    preclude the presence of hazardous substances (e.g.,
    contamination at loading docks but not elsewhere on
    site)

   • Contaminated areas covered by more than two feet
    of fill  or other materialJ

(Refer to specific examples in Highlights 9-3 through 9-6
in the Hazard Ranking System Guidance Manual, 1992,
OSWER Directive 9345.1-07.)

Areas of observed contamination can be established with
sampling locations and analytical data that meet the HRS
criteria    for   observed   contamination,    including
determination  of background levelJ.  A minimum of
three  contaminated samples is sufficient to establish an
area  of  observed contamination for soil. The  area of

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observed contamination  includes  the  three  sampling
points and  the area within them, except excluded sub-
     i i
areas.u

Points and linear strips of observed contamination may
be evaluated as areas of observed contamination for the
soil exposure  pathway,  even though  an actual  "area"
cannot be delineated. For soils, one contaminated sample
denotes  a  point of  observed contamination.   Two
contaminated  soil samples  denote a linear  strip  of
observed contamination. Either a point or a linear strip
can be used to identify other targets and to demonstrate
a hazardous waste quantity value greater than zero. This
method, however, should not be used indiscriminately to
calculate waste quantity.

For non-soil  sources,  such as waste piles,  observed
contamination at a single point generally is sufficient to
establish the   entire source as an area  of  observed
contamination.
Inferring an Area of Observed
For contaminated soil, an area of observed contamination
may be inferred within sampling locations that meet the
observed  contamination  criteria  and  have  proper
documentation. Select sampling locations that will allow
maximum  use   of  inferred  areas  of  observed
contamination.  This strategy may identify  more targets
with fewer  samples.   Consider the  following when
inferring an area of observed soil contamination:

  • Density of sampling points
  • Physiography
  * Topography and drainage  patterns
  • Operational history
  • Transport and deposition  of hazardous substances,
    such as wind dispersion
  • Contamination in  the downgradient  portion of a
    well-defined migration route
  • Data derived  from  other  investigations  (e.g.,
    geophysical surveys)
  • Soil staining
  • Stressed vegetation patterns
  • Aerial and ground photography
  • Infrared satellite imagery  indicating soil anomalies
  • Use of composite samples (Samples within one grid
    cell may be combined; vertical samples from a single
    point within a  zero to two  foot depth  may be
    combined.   In  general,  do  not  use  non-grid
    horizontal composite  samples to infer areas  of
    observed contamination.) u
Consider the modes of contaminant transportation and
deposition   when  inferring  an   area   of  observed
contamination. Contaminants dispersed by air would be
distributed  differently than those transported by water;
take this into account when planning sampling.  Do not
infer an area of observed contamination between soils in
the floodplain of a contaminated surface water body and
those contaminated from other modes  of transportation
and deposition.

Determining Levels of Actual Contamination

Documentation  of  observed   contamination  is   a
prerequisite  for  evaluating  actual contamination  at
targets. Actual contamination is  evidence that targets
have contact  with  the hazardous  substance(s)  from
observed   contamination.     The  level  of   actual
contamination is determined  by comparing the release
sample concentration  to  media-specific  benchmark
values, where available. Level I contamination is at or
above benchmarks; level II is below benchmarks.  Note
that the presence of contamination at targets is not  in
itself sufficient to establish observed  contamination or
actual  contamination.2  Observed contamination samples
can  be strategically located to  establish an  area  of
contamination and to include one or more targets (dual
purpose sampling). Analytical data with appropriate and
adequate quality assurance/quality control (QA/QC) are
needed since benchmarks are expressed in concentration
units.    Analytical  data  should  provide  definitive
identification of the hazardous substances.3

Level  I actual contamination concentrations cannot be
inferred between contaminated soil sampling points. The
inferred area of observed contamination is evaluated as
Level  II, even if Level I concentrations are  found  at
sampling points.2
Use of Grid Samples

Grid samples may consist of grab samples (from a single
point) or  composite samples  (from multiple points).
Either grab or composite grid  samples  may be used to
evaluate the  area  of observed contamination  if the
following conditions apply:

   • Samples are obtained from a depth of two feet or
     less from the source or soil surface, and the source
     is not covered by impervious material

   • The available  analytical data verify analyte identity
     and quantitation with adequate QA/QC (this may

-------
     consist  of  confirming 10  percent
     analyses by definitive methods)}
                                       of
screening
   •  The verified analytical data meet the HRS definition
     of observed contamination as defined in section 2.3
     of the Hazard Ranking System, Final Rule

Contaminated  grid  cells  are  those  with  identified
hazardous substances that meet HRS criteria for depth,
attribution to the site, and significance above background
level. The area within these grid cells may be used to
define an area of observed contamination.

Contamination can be inferred at grid cells not sampled
if they lie between contaminated grid cells.   Grid cells
lying within  inferred contaminated cells are  themselves
considered inferred contaminated cells. The  area within
inferred contaminated grid cells may be included as part
of an area  of  observed  contamination.   (Refer  to
Highlight 9-4 in the Hazard Ranking System Guidance
Manual,  1992, OSWER Directive 9345.1-07.)

The   following  guidelines  should  be  used  when
considering grid sampling data:

  •  Exclude from the  area of observed contamination
     uncontaminated grid cells and unsampled grid cells
     that do not lie  between contaminated  or  inferred
     contaminated ones.

  •  Subtract  from  the defined  area  of  observed
     contamination any grid cells or sub-areas which are
     covered with  impervious materials,  or  meet other
     criteria  for exclusion.2

  •  Use the same methods to define both the excluded
     sub-areas and areas  of observed contamination. All
     samples should be of the same quality, and analyzed
     by similar procedures. Exclude sub-areas from the
     inferred area of observed contamination on a case-
     by-case basis.

  •  Composite grid samples may  establish Level II
     actual  contamination; specific  grab samples are
     required to establish Level I actual contamination.
DeterP"n'ng a
Sources Other
                Area of Observed  CQ"tflmination
                    §Q'|
Sources other than contaminated soil, such as waste piles,
impoundments, and containers, can be evaluated for the
soil exposure pathway.  The entire source is considered
an area of observed contamination if a sample collected
from it meets the criteria for observed contamination.2
Determine an area of observed contamination as follows:

   • Impoundment, landfill, and land treatment
    — Use the surface area of the source w

   • Pile — Use the surface area of the pile

   • Ruptured tanks,  drums, and other containers — Use
    the surface area of the  container or the land area
    under  the  container  (Note:    Do not  evaluate
    containers which have not leaked.)
                Example Site

                EPA conducted an Expanded Site Inspection (ESI) at a
                scrap metal yard in an industrial area to assess inorganic
                soil contamination. For a number of years, reclamation
                of automotive batteries bad taken place at the scrap yard,
                which was surrounded by a residential area.  A prior
                removal action mitigated severe soil contamination and
                secured the site from public access, but did not generate
                enough data to allow HRS evaluation.

                The   removal   action   uncovered   extensive   lead
                contamination  within  the  property  boundaries  of  the
                scrap yard, but had not evaluated the residential area.
                Eleven residences were situated on a tract adjacent to the
                site;  six residences abutted the scrap yard boundary.
                The proximity of the residential area raised the possibility
                that inhabitants could be exposed to lead from sources at
                the scrap yard.  A study of the  area revealed that lead
                could be deposited on the residential tract from surface
                runoff,  dispersion of participates  from  wind,   and
                vehicular  movement.   EPA  hypothesized that these
                modes of soil  transport  created an area of observed
                contamination in the residential tract.

                EPA collected  soil samples at each residence and at
                border  areas  to demonstrate  attribution  of   lead
                contamination by area! contiguity. Background samples
                were collected  at nearby areas  that were  outside the
                influence of sources at the scrap yard.  In an industrial
                area, it is always possible that background concentration
                 is  inflated from various  sources.  To account for this
                 possibility, seven spatially divergent  sample locations
                were  selected  within  the background area to ensure
                 provision of at least one representative background level.
                 Soils  in  all sample  locations were classified  so  that
                 release  samples  could be compared to  background
                 samples of similar soil composition.  All samples were

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         Figure 2:  Lead Concentrations in Residential Soils Related to Various Background Levels
         r\
         0>
 13-

 12-
 11 -

 10-

1  9-
          o
         u
         T3
          (0
          0)
  5-

  4-

  3-

  2-

  1-
                                         A - Level  l  Benchmark
                                         8 - 3X  Lowest Background
                                         C - 3X  Second Highest Background
                                         0 - 3X  Highest Background
                   1   2   3  4   5   6   7   8  9  10  11 12  13 14  15 16  17 18  19 20

                                      Res i dent i a I  Samp Ie  Number
collected  within  six  inches  of the  ground  surface.
Analytical  results from  the  area  of suspected  lead
contamination revealed lead concentrations ranging from
740 to 12,600 mg/kg (see figure 2).  Lead concentrations
from the  background  area ranged from 448 to 1,410
mg/kg.  Observed and actual contamination were clearly
established,  since   three   residences   had   lead
concentrations greater  than or equal to three times the
highest background level, and the lead was attributable to
the scrap yard.   Data from local  and regional health
agencies indicated that the highest background level,
which is usually the one selected for HRS evaluation, was
inflated.  If this were the case, the number of residences
with actual contamination would  be underestimated.
EPA decided to examine  the  background data more
closely.

According to data from the health agencies, background
levels of lead in area soils ranged from 500 to 1000
mg/kg.   Statistical analysis of the background levels
showed  that the  highest value, 1,410 mg/kg, was not an
outlier, but did lie well above the upper quartile of the
data distribution.   EPA suspected  that  the  highest
background value was not a representative level, and
considered using a  statistically derived  concentration.
The use of the  mean  concentration  was  immediately
                                             rejected because it was subject to inflation from the
                                             highest value.  In such a skewed data set, the  median
                                             would be a more stable estimator of typical background
                                             value. The median background level of 625 mg/kg was
                                             consistent with published data.  It was, however, only an
                                             inference of typical background level, not a real sample
                                             concentration.     The  second  highest   background
                                             concentration,  856 mg/kg, fell within the  range of the
                                             published data. EPA chose this value because  a single
                                             background   sample  is  a   sufficient,  defensible
                                             determination of background level under the HRS.  Use
                                             of the  lowest  background  concentrations was  not
                                             considered because it  could erroneously indicate observed
                                             contamination in areas where lead  concentrations  were
                                             below three times the reasonable background level.  The
                                             lowest concentration  is not defensible in HRS evaluation
                                             when there are higher background values obtained  from
                                             sampling.

                                             Samples from seven  residences had lead concentrations
                                              in excess of three times background level (i.e.,   3 x 856
                                              mg/kg  = 2^68 mg/kg).   The health-based benchmark
                                              for  lead in soil is  500 mg/kg.   The  ESI  therefore
                                              established an area  of observed contamination beyond
                                              the facility's boundaries and found seven residences with
                                              Level I actual contamination.

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   Smart Sampling Example:  Use of Aerial
   Photographs

   The use of aerial photographs during early site
   screening can provide valuable information for
   optimal selection of sampling locations.
   Further,  photos can facilitate potentially
   responsible party (PRP) searches and
   enforcement activities. Recent aerial
   photography may reveal burial outlines,
   staining, or stressed vegetation.  In one
   instance, aerial photos of a landfill pinpointed
   locations of buried drums more precisely than
   did borings.  In another instance, aerial photos
   of two adjacent oilfield-related sites revealed
   the possibility  of burled waste pits.
   Subsequent samples from the locations
   confirmed the  existence of the waste pits.
   Whenever possible, use aerial photographs to
   help delineate site  contamination, aid in
   enforcement, and save money by narrowing
   the areas that  must be sampled.
Summary

Surficial soil and other source samples may be used to
establish  observed  contamination for the soil exposure
pathway.  Observed contamination can be documented
only by chemical analysis.  Direct  observation and the
potential  for observed contamination are not evaluated
for this pathway. Sample on the property, within 200 feet
of targets, and within two feet of the source surface.
Multiple  samples which  meet  the  HRS  criteria for
observed contamination may be used to delineate an area
of observed contamination  by inferring contamination
between  sampling points.    The scope  of the Site
Inspection generally does not warrant fully delineating
areas that are not subject to observed  contamination.
The  primary objective is to  identify targets that may
come in contact  with hazardous substances at the site.
Whenever possible, select sampling locations which serve
the dual purpose of establishing observed contamination
and identifying targets.
References

1.  U.S.  Environmental   Protection  Agency,  1992.
    Guidance for Performing Site  Inspections Under
    CERCLA.  Office of  Solid Waste  and Emergency
    Response.  Directive 9345.1-05.

2.  U.S.  Environmental   Protection  Agency,  1992.
    Hazard Ranking System Guidance Manual. Office of
    Solid Waste  and Emergency Response.   Directive
    9345.1-07.

3.  U.S. Environmental Protection Agency, 1993. Data
    Quality Objectives Process for  Superfund, Interim
    Final Guidance.  Office of Emergency and Remedial
    Response. Directive 9355.9-01.

4.  U.S.  Environmental   Protection  Agency,  1990.
    Hazard Ranking System, Final Rule. 40  CFR Part
    300.

-------
                                   Additional copies can be obtained from:

                                National Technical Information Service (NTIS)
                                       U.S. Department of Commerce
                                           5285 Port Royal Road
                                           Springfield, VA 22161
                                               (703) 487-4650
                                             Order #94-963312
United States
Environmental Protection Agency
5204G
Washington, DC 20460

$300 Penalty for Private Use

-------
Minimize aeration of a sample to prevent reducing the
concentration of contaminants such as volatile organic
chemicals.

Consider seasonal and other potential variations such as
irrigation and flooding when sampling in this pathway.
Deep,  slow-moving surface water bodies often  exhibit
some chemical  or thermal stratification.  Stratification
also occurs where two streams converge. The absorption
or dilution of substances is affected by stream movement,
and depositional conditions vary within the riffles or close
to stream edges.2

Sediment samples  may be used to document historical
releases to the water body. Ideally, the characteristics of
the suspected contaminant(s) should be known to select
the best sample medium, location, and sampling method.
Grain  size,  organic  content,  and structure  can affect
adsorbance of substances  to sediments. For example,
trichloroethylene  (TCE)  adsorbs to certain  particles,
which may bias a sample. J Sediments are scoured  and
deposited in bends of streams and other flowing surface
water bodies. Sample from like areas (e.g., inside bend
deposition areas) for comparability.

Distinguish  sediments  from  soils,  especially  when
sampling along  the edge of a water body. Note that in
arid or semiarid locations (less than 20 inches mean
annual precipitation),  "sediments" include  areas with
intermittently flowing  waters  as well  as  contiguous
intermittently flowing ditches.  Contamination in these
areas should be evaluated in the surface water pathway.3

Tissue sampling poses challenges - for comparability
because of differences between members of  the same
species, differences between species, variations within a
study  population,  species   mobility,   and   tissue
differentiation.   The target sample species  should be
examined for type of organism, approximate age, gender,
size of population,  migratory nature, and  seasonal,
feeding,  spawning, • or  other  periodic activities  that
influence  concentration  of   substances  within  the
organism.2 Tissue samples can be used to determine an
observed release only under limited circumstances; they
are more readily used to document actual contamination.
It is prudent to collect tissue  samples in concert with
other sampling activities when documenting an observed
release.

For tissue sampling, document both the rationale for the
tissue  selection,  and  the  accuracy of measurement.
Edible  tissues  from  sessile,  benthic  organisms  are
preferred for HRS  evaluation.   (Non-sessile benthic
organisms,  finfish,  amphibians, and reptiles generally
should not be used.)
Air Pathway

It  is important to consider temporal variability in air
sampling  because   large   variations   in   substance
concentration  can  occur  over a  very  short  time.
Emissions characteristics depend upon topography and
changeable   atmospheric  conditions,   including
temperature,   pressure,  wind  speed  and  direction,
precipitation, and atmospheric stability.

Monitoring  wind direction is  prudent  to  document
migration of hazardous  substances from the source.
Wind roses, which detail the percentage of predominant
wind  direction, should be developed for the sampling
period to document shifts in wind direction.J

For  the  air pathway, an air sample may be  used  to
document  both  an   observed release  and  actual
contamination of targets within a certain radius from the
source. (In contrast, the ground water pathway requires
sampling  at  the target; the surface  water  pathway
requires  sampling at or beyond the target to establish
actual contamination.)

An observed release by chemical analysis is not easy to
establish for the air pathway because of the difficulty of
obtaining comparable and verifiable samples. The HRS
evaluates outdoor ambient air conditions only; indoor air
samples are not evaluated for this pathway.2
Partial Attribution and Multiple Source Sites

Sources of contamination other than those found at the
site  under  investigation are  often  present.   Where
attribution is questionable, sampling should  produce
analytical data demonstrating that the contamination is at
least partially attributable to the site. Contributions from
sites sometimes can be isolated by identifying hazardous
substances unique to the site under investigation. This
may  require special  analytical  services  and  close
evaluation of data.  Knowledge of the nearby facilities'
disposal practices and wastes is helpful.'

Attribution may be  established through  the  use of
manifests, labels, records, oral or written statements, or
other information regarding hazardous substances present
at the site or at  alternative sources. If these references
confirm the presence of a hazardous substance in release
samples, attribution generally can be established even if
specific  sources  where  the  substance  was deposited
cannot be documented.2

Establishing background  levels  is   important  when
attributing  hazardous substances to  varied  sources.
Background and release sample data should be from the
same  medium* using  similar sampling and analytical
methods. Background samples should be collected from

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outside the influence of contamination from  the  site
under  investigation, but do  not have  to  be  free of
contamination.   The data need only support  that the
release sample  concentration is beyond a reasonable
background level. Thoroughly review and document the
location  of potential alternative sources  so  that  the
appropriate background sampling  locations  can  be
selected. Many hazardous substances may be widespread
in the vicinity of the site. Substances may originate from
non-point  sources  such  as  pesticides  and  lead.
Background levels  for  ubiquitous substances should
account for local variability, several samples  may be
required to establish this variability.2

Obtain  sufficient  samples  from  the  site  under
investigation and from other known potential sources (or
other adjacent sites) to demonstrate that an increase in
contaminant levels is attributable to the site. Additional
information beyond analytical samples may be  required
if the  other sites release intermittently. To  attribute
contamination sufficiently, collect the following  data:

  • Concentration gradients (e.g., establish an observed
    release and attribution with samples from  multiple
    wells or a  series of samples between the  site  and
    alternative  sources)
  • Flow gradients and other information about the
    media of concern
  • Data that associate  the site with a unique substance
    or unique ratios of  different substances 2

Complex   factors  affecting   attribution  (e.g.,  soil
contamination  in   an   industrial  area)  may  require
conducting an expanded SI.  In many cases, attribution
concerns may be addressed by fully characterizing all
sources at a site and those of neighboring sites. l

To  establish attribution for the ground  water  pathway,
sample wells located between site sources and alternative
sources.  Three wells generally are needed to define  flow
direction and to verify the source versus an alternative
source(s).  For surface water, a release  sample may be
collected downstream of or at the confluence.  Sample
background and attribution along  each  tributary  if
multiple sources are located upstream. *
Transformation Products

Transformation  products are substances found when a
hazardous substance is changed in the environment by
physical, chemical,  or  biological  processes.    Most
transformation products at hazardous waste sites are the
result of degradation.2

An observed release'for transformation products must be
documented by chemical analysis and the transformation
product must be a hazardous substance.2
Document the presence of a transformation product in a
release sample at levels significantly above background
level  to  attribute  the  parent substance(s)  and  the
transformation product  to  the  site.    The  following
references may be  useful for  documenting the parent
substance and transformation product relationship:

   • Site-specific studies on the transformation process by
    qualified   research   organizations   (e.g.,   U.S.
    Government agencies, universities)
   • Technical reports on transformation  from EPA's
    Office of Research and Development
   • Databases containing EPA-reviewed information
   • Articles from peer-reviewed journals
   • Textbooks on  soil,  environmental  microbiology,
    biotechnology, and biotreatment processes and their
    effectiveness 2

For determining an observed release, conditions at the
site  must  be  conducive to,  or  must  not  impede,
transformation, and at least one source must be able to
release the substance to the pathway.2
      Smart Sampling Example:  Minimizing
      Investigation Derived Wastes (IDW)

      Solvents, equipment, and other materials
      used in site investigation and cleanup may
      themselves end up as hazardous waste.
      Disposal of IDW at an approved facility
      increases site costs and adds to the overall
      waste disposal burden.  Take  precautions to
      minimize waste generated on  site. Solvents
      should be recycled rather than incinerated,
      whenever feasible. In many instances,
      drums may be cleaned and reconditioned
      instead of sent to a landfill. A series of
      treatment steps may reduce the final volume
      of hazardous waste for disposal. Consider
      pollution prevention when planning response
      actions.
 Radionuclide Sites

 The criteria for  documenting  an observed release by
 direct observation apply to radionuclides.  Table 7-1 in
 the Hazard Ranking System, Final Rule provides the HRS
 factor categories  that  are evaluated differently  when
 radionuclides are present.3

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For  documenting  an  observed release by  chemical
analysis, radionuclide sites are divided into three groups:

  1.      Radionuclides  that   exist   naturally   and
         ubiquitous radionudides.
  2.      Man-made  radionudides  which  are  not
         ubiquitous.
  3.      External  gamma  radiation   (for  the  soil
         exposure pathway only).

Observed releases from a combination of radionudides
and   hazardous wastes (mixed  waste)   should  be
documented separately.

Establishing an observed release requires:

  • Identification of the radionuclide of concern and the
    physical and chemical properties of the radionuclide
  • On-site   and   background  activities   for   that
    radionuclide
  • SQL or other detection limit for the radionuclide
For gamma radiation, measure the exposure rate at
meter above ground for the soil exposure pathway.
one
Specific requirements for establishing an observed release
for each of the three groups of radionudides can be
found in Section 7.1 of the Hazard Ranking System, Final
Rule.
           Summary

           Documenting an observed release for NFL rule-making
           purposes requires evidence that the concentration of the
           hazardous substance of concern significantly exceeds the
           background level.   The  hazardous substance  must be
           attributable at least in part to the site under investigation
           (except for ground water plume sites with unknown
           sources).    Establishing  an observed release  requires
           thorough documentation. The sampling design should
           attempt to meet multiple HRS data needs with a limited
           number of samples.
References

1.   U.S.  Environmental  Protection  Agency,  1992.
Guidance for Performing Site Inspections Under CERCLA.
Office  of  Solid  Waste  and  Emergency Response.
Directive 9345.1-05.

2.  U.S. Environmental Protection Agency, 1992. Hazard
Ranking System Guidance Manual. Office of Solid Waste
and Emergency Response. Directive 9345.1-07.

3.   U.S.  Environmental Protection Agency,  Hazard
Ranking System, Final Rule. 40 CFR Part 300.

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                                Additional copies can be obtained from:

                             National Technical Information Service (NTIS)
                                      Department of Commerce
                                        5285 Port Royal Road
                                        Springfield, VA 22161
                                            (703) 487-4650
                                         Order # 94-963314
United States
Environmental Protection Agency
5204G
Washington, DC 20460

$300 Penalty for Private Use

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                   United States
                   Environmental Protection
                   Agency
Office of
Solid Waste and
Emergency Response
Directive 9285.7-18FS
PB94-963312
EPA/540/F-94/029
October 1994
    &ER&    Establishing  Areas  of  Observed
                   Contamination
   Office of Emergency and Remedial Response
   Hazardous Site Evaluation Division (5204G)
         DRAFT
                            Quick Reference Fact Sheet
Abstract

This fact sheet addresses the use of analytical data to establish areas of observed contamination at a hazardous waste site
when evaluating the soil exposure pathway under the Hazard Ranking System (HRS). The data may also be used to
evaluate hazardous waste quantity for some HRS source types. The soil exposure pathway is evaluated only if observed
contamination  is  established.  Establishing observed contamination, defining the area of observed contamination, and
identifying areas of differing levels of contamination are critical in evaluating the soil exposure pathway.
Introduction

The Hazard Ranking System (HRS) establishes general
criteria to document an observed release of hazardous
substances  to  the migration pathways  (ground water,
surface  water,  air)  and  to  document  observed
contamination in the soil exposure pathway. An observed
release is evidence that contaminants have migrated away
from a site to a migration pathway. In contrast, observed
contamination  is   evidence  that  targets  (human
populations, resources, and sensitive environments) have
come into direct contact with the contaminants.  Unlike
the migration  pathways,  the soil exposure  pathway is
evaluated based on current,  rather  than historical,  site
conditions. An exception occurs when a removal action
is performed under EPA oversight during or after a Site
Inspection  (SI).  In such  a case,  the soil exposure
pathway could be evaluated based on conditions prior to
the removal action  (see the fact  sheet The Revised
Hazard Ranking System: Evaluating Sites After Waste
Removals," OSWER 9345.1-03FS, for more information
on removal actions performed during or after an SI).

The  HRS criteria for documenting  an observed release
and observed contamination are: there must be evidence
of a hazardous substance in the medium of concern at a
concentration  significantly above the background level
and at or above the appropriate detection limit,  and the
         hazardous  substance  must  be  at  least  partially
         attributable to a release from the sice under investigation
         (see  figure  1). (For more information on observed
         releases, refer to the fact sheet "Establishing an Observed
         Release,' OSWER Directive 9285.7-20FS.)
         Establishing Observed Contamination

         When evaluating the soil exposure pathway, observed
         contamination must be documented by chemical analysis
         of samples from contaminated  areas.   The  source
         samples are  compared to a background level.  Most
         samples consist of soil, but leachate, waste, sediment, and
         other  surfitial  samples  may  be  collected. l   In
         comparison,  an observed release in  the  migration
         pathways  may  be  documented  either  by  direct
         observation or by chemical analysis of release samples
         compared to  a background level.

         Three  criteria  must be  met  in  order  to  document
         observed contamination by chemical analysis:

            1.     The  source sample concentration must be
                  greater than or equal to the appropriate
                  detection limit (e.g., sample quantitation limit
                  [SQL]). The detection limit must be properly
                  determined.

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                        Figure 1: Flowchart for Establishing Observed Contamination
                              !• the concentration of
                              hazardous aubatance in
                                tha source tampla
                                sianificantiy above
                                  oackground?
YES
No obi
contam
at th«

lerved NO
sit*
k
NO
                                                                                   YES
                    * Direct observation does not apply to
                          the soll exposure pathway

                    Figure adapted from reference 2 CP   563
                  Observed
                contamination
                established by
               chemical anaJyiia
  2.     If the hazardous substance of concern is not
         detected in the background samples (or  its
         concentration is less than the detection limit),
         the  source sample  concentration  must  be
         greater than or equal to its detection limit, if
         both  detection limits  are  the  same.    If
         background levels are greater than or equal to
         the   detection  limit,  the  source  sample
         concentration must be at least three times the
         background level.  Note that  detection limits
         may be different  for source and background
         samples.

  3.     The  hazardous substance is  present  at the
         surface or is covered by no more than two feet
         of  penetrable material (except for gamma
         radiation  emitters,  which have  no depth
         restriction).a
Sampling to Meet the MRS Sampling Objective

In the soil exposure pathway, there is no  acceptable
documentation of observed  contamination  based  on
direct observation, and the potential for contamination is
not evaluated. Consider both the types and locations of
targets when selecting sampling locations.  Establish an
area of observed contamination as close  to targets as
possible.   Evaluate  targets under the HRS  resident
population   threat  when   an   area  of  observed
contamination lies on the site property and within 200
feet of a residence, school, day care center, or workplace.
Evaluate sensitive environments and resources in  the
resident population threat only if the area of observed
contamination  lies within site  boundaries.  Evaluate
targets beyond 200 feet but within one mile of the area
of  observed  contamination  under  the  HRS  nearby
population threat.4  Collect samples no deeper than two
feet below  the surface.   Document  the  absence of  a
maintained, essentially impenetrable cover material (e.g.,
asphalt,  concrete)  over  any portion  of an  area  of
observed contamination. * Since surficial contamination is
not limited to soil, sampling of other surface media, such
as leachate or waste, should be considered.

Attribute   contamination  to   a  site   by  collecting
appropriate background samples outside the influence  of
sources. Obtain source samples from locations where the

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Exhibit 1: Background Samples for Areas of Observed Contamination
Source
Contaminated soli
Tanks/Drums filled with contaminated soil
Tanks/Drums containing liquid or solid wastes
Landfill*
Piles*
Surface Impoundment (liquid)*
Surface impoundment (sludges or backfilled)*
Other sources
Background Sample
Soil In vicinity of the site1
Same as for the soil at the site
Background is zero
Soil in vicinity of the site
Soil in vicinity of the site
Aqueous samples from vicinity of the site;
background may be zero
Soil in the vicinity of the site
Review on a site-specific basis
'See sections 5.1 and 5.2 of reference 2 for additional considerations.
*For these source types, the Indicated sample is likely to be the most appropriate background.
Figure adapted from Highlight 9-1 of reference 2 (p. 344)
substances are suspected to have been deposited (e.g.,
contaminated soil along the flood plain of a contaminated
surface water body). 2  Exhibit 1 suggests  appropriate
locations for background samples by source type.
Evaluating  Waste  Quantity  by  Defining Areas  of
Observed Contamination

Identify and delineate areas of observed contamination
for the following reasons:

1.   The soil exposure pathway can be evaluated only if
    there are areas of observed contamination.

2.   Target values are assigned based on the distance of
    targets from  the area of observed contamination.

3.   Waste quantity can be calculated based on the area
    of observed contamination.

A  site  may have  more  than one  area  of observed
contamination.   Each area of observed contamination
may be  associated with its own targets.  Assign a source
hazardous waste quantity value for each area.  Sum  the
source hazardous waste quantity values assigned to each
area of  observed  contamination to determine the waste
quantity factor value for the soil exposure pathway.2
Some soil areas cannot be included in evaluating an area
of observed contamination. Exclude the following sub-
areas:

   • Areas   covered  by   permanent   or  otherwise
    maintained  and essentially impenetrable material
    (e.g., asphalt, concrete)

   • Areas of higher  ground not  influenced by runoff
    from the site, if contamination results from runoff

   • Areas where the types of operations at a facility
    preclude the presence of hazardous substances (e.g.,
    contamination at loading docks but not elsewhere on
    site)

   • Contaminated areas covered by more than two feet
    of fill or other material2

(Refer to specific examples in Highlights 9-3 through 9-6
in the Hazard Ranking System Guidance Manual, 1992,
OSWER Directive 9345.1-07.)

Areas of observed contamination can be established with
sampling locations and analytical data that meet the HRS
criteria   for   observed   contamination,   including
determination  of background level2.  A minimum of
three  contaminated samples is sufficient to establish an
area  of  observed contamination for soil.  The area of

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observed  contamination  includes  the  three sampling
points and the area within them, except  excluded sub-
areas.14

Points and linear strips of observed contamination may
be evaluated as areas of observed contamination for the
soil  exposure  pathway,  even though  an actual  "area"
cannot be delineated. For soils, one contaminated sample
denotes  a point  of  observed  contamination.   Two
contaminated  soil samples  denote a  linear  strip  of
observed contamination. Either a point or a linear strip
can be used to identify other targets and to demonstrate
a hazardous waste quantity value greater than zero. This
method, however, should not be used indiscriminately to
calculate waste quantity.

For  non-soil  sources,  such as  waste  piles, observed
contamination at a single point generally is sufficient to
establish the  entire source  as  an area  of observed
contamination.
Inferring an Area of Observed Contamination

For contaminated soil, an area of observed contamination
may be inferred within sampling locations that meet the
observed  contamination  criteria   and  have  proper
documentation. Select sampling locations that will allow
maximum   use  of  inferred  areas  of  observed
contamination.  This strategy may identify  more targets
with fewer  samples.    Consider the  following  when
inferring an area of observed soil contamination:

  • Density of sampling points
  • Physiography
  • Topography and drainage patterns
  • Operational history
  • Transport and  deposition  of hazardous substances,
    such as wind dispersion
  • Contamination in  the downgradicnt  portion of  a
    well-defined migration route
  • Data  derived  from  other  investigations  (e.g.,
    geophysical surveys)
  • Soil staining
  • Stressed vegetation patterns
  • Aerial and ground photography
  • Infrared satellite imagery  indicating soil anomalies
  • Use of composite samples (Samples within one grid
    cell may be combined; vertical samples from a single
    point within a zero to  two  foot depth  may be
    combined.   In  general, do  not  use  non-grid
    horizontal composite  samples to infer  areas  of
    observed contamination.)u
Consider the modes of contaminant transportation and
deposition   when  inferring  an   area   of   observed
contamination.  Contaminants dispersed by air would be
distributed  differently than those transported by water;
take this into account when planning sampling. Do not
infer an area of observed contamination between soils in
the floodplain of a contaminated surface water body and
those contaminated from other modes of transportation
and deposition.

Determining Levels of Actual Contamination

Documentation  of  observed   contamination  is   a
prerequisite  for  evaluating  actual  contamination  at
targets.  Actual contamination is  evidence that targets
have  contact  with  the hazardous substance(s)  from
observed   contamination.     The  level   of   actual
contamination is determined by comparing the release
sample  concentration  to   media-specific  benchmark
values, where available. Level I contamination is at or
above benchmarks; level II is below benchmarks.  Note
that the  presence of contamination at targets is  not  in
itself sufficient to establish  observed  contamination or
actual contamination.2  Observed contamination samples
can  be  strategically located to  establish  an area  of
contamination and to include one or more targets (dual
purpose sampling). Analytical data with appropriate and
adequate quality assurance/quality control (QA/QC) are
needed since benchmarks are expressed in concentration
units.    Analytical  data   should provide  definitive
identification of the hazardous substances.3

Level I actual  contamination concentrations cannot be
inferred between contaminated soil sampling points. The
inferred area of observed contamination is evaluated as
Level II, even if Level I concentrations are found  at
sampling points.2
Use of Grid Samples

Grid samples may consist of grab samples (from a single
point) or  composite samples  (from multiple points).
Either grab or composite grid  samples  may be used to
evaluate  the  area of  observed contamination  if the
following conditions apply:

   • Samples are obtained from a depth of two feet or
     less from the source or soil surface, and the source
     is not covered by impervious material

   • The available analytical data verify analyte identity
     and  quantitation with adequate QA/QC (this may

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     consist of  confirming 10  percent
     analyses by definitive methods)'
of
screening
   •  The verified analytical data meet the HRS definition
     of observed contamination as defined in section 2.3
     of the Hazard Ranking System, Final Rule

Contaminated  grid  cells  are  those  with  identified
hazardous substances that meet HRS criteria for depth,
attribution to the site, and significance above background
level. The area within these grid cells may be used to
define an area of observed contamination.

Contamination can be inferred at grid cells not sampled
if they lie between contaminated grid cells.   Grid cells
lying within inferred contaminated cells are themselves
considered inferred contaminated cells.  The area within
inferred contaminated grid cells may be included as part
of an area  of  observed  contamination.   (Refer  to
Highlight 9-4 in the Hazard Ranking System Guidance
Manual,  1992, OSWER Directive 9345.1-07.)

The   following  guidelines   should  be  used  when
considering grid sampling data:

   *  Exclude from the area of observed contamination
     uncontaminated grid cells and unsamplcd grid cells
     that do  not lie  between contaminated  or  inferred
     contaminated ones.

   •  Subtract  from  the  defined   area of  observed
     contamination any grid cells or sub-areas which are
     covered with  impervious materials,  or  meet other
     criteria for exclusion.2

   •  Use the same methods to define both the excluded
     sub-areas and areas of observed contamination. All
     samples should be of the same quality, and analyzed
     by similar procedures. Exclude sub-areas from the
     inferred area of observed contamination on a case-
     by-case basis.

   •  Composite grid  samples may establish Level II
     actual  contamination; specific  grab samples  are
     required to establish Level I actual contamination.
Detenr''"'"g an Area of Observed  ^*o"^"iination for
Sources Other Than Soil

Sources other than contaminated soil, such as waste piles,
impoundments, and containers, can be evaluated for the
soil exposure pathway.  The entire source is considered
an area of observed contamination if a sample collected
from it meets the criteria for observed contamination.J
Determine an area of observed contamination as follows:

  • Impoundment, landfill, and land treatment
    — Use the surface area of the sourcel4

  • Pile — Use the surface area of the pile

  • Ruptured tanks,  drums, and other containers — Use
    the surface area of the container or the land area
    under  the container  (Note:    Do not  evaluate
    containers which have not leaked.)
                    Example Site

                    EPA conducted an Expanded Site Inspection (ESI) at a
                    scrap metal yard in an industrial area to assess inorganic
                    soil contamination. For a number of years, reclamation
                    of automotive batteries had taken place at the scrap yard,
                    which was surrounded by a residential area.  A prior
                    removal action mitigated severe soil contamination and
                    secured the site from public access, but did not generate
                    enough data to allow HRS evaluation.

                    The  removal   action  uncovered  extensive   lead
                    contamination within the  property boundaries of the
                    scrap  yard, but had not evaluated the residential area.
                    Eleven residences were situated on a tract adjacent to the
                    site;  six residences  abutted the scrap yard boundary.
                    The proximity of the residential area raised the possibility
                    that inhabitants could be exposed to lead from sources at
                    the scrap yard.  A study of  the area revealed that lead
                    could be deposited on the residential tract from surface
                    runoff,  dispersion  of  participates  from  wind,  and
                    vehicular  movement.  EPA  hypothesized  that  these
                    modes of soil  transport  created an  area  of observed
                    contamination in the residential tract.

                    EPA  collected  soil samples at  each residence and at
                    border   areas  to  demonstrate  attribution  of  lead
                    contamination by area! contiguity.  Background samples
                    were  collected  at nearby areas that  were  outside  the
                    influence of sources  at the scrap yard. In an industrial
                    area, it is always possible that background concentration
                    is inflated  from various sources.  To account  for  this
                    possibility, seven  spatially  divergent sample  locations
                    were  selected  within  the background area  to  ensure
                    provision of at least one representative background level.
                    Soils  in all  sample  locations were  classified  so that
                    release  samples  could be compared, to  background
                    samples of similar soil composition.  All samples were

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         Figure 2:  Lead Concentrations in Residential Soils Related to Various Background Levels
         /-v
         C»
C ' '
5*
«s
r en
13-

12-
11 -

10-

 9-
          0
         U

         t)
          10
          0)
     7-
   u
  f 6-

     5-


     3-

     2-

     1-
                                         A - Level  I  Benchmark:
                                         B - 3X  Lowest Background
                                         C - 3X  Second Highest Background
                                         0 - 3X  Highest Background
                   1  2   3   4   5   6   7   8  9  10  11 12  13 14  15  16  17  18  19  20

                                      Res i dent i a I  Samp Ie  Number
collected  within  six  inches  of the  ground  surface.
Analytical  results  from  the  area  of suspected  lead
contamination revealed lead concentrations ranging from
740 to 12,600 mg/kg (see figure 2).  Lead concentrations
from the  background  area ranged from 448 to 1,410
mg/kg.  Observed and actual contamination were clearly
established,  since   three  residences   had   lead
concentrations greater  than or equal to three times the
highest background level, and the lead was attributable to
the scrap  yard.  Data from local  and regional health
agencies indicated that the highest background level,
which is usually the one selected for HRS evaluation, was
inflated. If this were the case, the number of residences
with actual contamination would  be  underestimated.
EPA decided to examine  the  background data more
closely.

According to data from the health agencies, background
levels of lead in area soils ranged from 500 to 1000
mg/kg.   Statistical analysis of the background levels
showed that the  highest value, 1,410 mg/kg, was not an
outlier, but did lie well above the upper quartile of the
data distribution.    EPA  suspected  that  the  highest
background value  was not a representative level, and
considered using a  statistically derived  concentration.
The use of the mean concentration  was  immediately
                                                 rejected because  it was subject to  inflation from  the
                                                 highest value.  In such a skewed data set, the median
                                                 would be a more stable estimator of typical background
                                                 value. The  median background level of 625 mg/kg was
                                                 consistent with published data. It was, however, only an
                                                 inference of typical background level, not a real sample
                                                 concentration.     The  second   highest  background
                                                 concentration, 856 mg/kg, fell within the range of the
                                                 published data. EPA chose this value because a single
                                                 background  sample   is   a   sufficient,   defensible
                                                 determination of background level under the HRS. Use
                                                 of  the lowest  background concentrations  was  not
                                                 considered because it could erroneously indicate observed
                                                 contamination in  areas where lead concentrations were
                                                 below three times the reasonable background level. The
                                                 lowest concentration is not defensible in HRS evaluation
                                                 when there are higher background values obtained from
                                                 sampling.

                                                 Samples from seven residences had lead concentrations
                                                 in excess of three times background level (i.e.,  3 x 856
                                                 mg/kg = 2,568 mg/kg).  The health-based benchmark
                                                 for  lead  in soil  is 500 mg/kg.   The ESI therefore
                                                 established an area of  observed contamination beyond
                                                 the facility's boundaries and found seven residences with
                                                 Level I actual contamination.

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   Smart Sampling Example:  Use of Aerial
   Photographs

   The use of aerial photographs during early site
   screening can provide valuable information for
   optimal selection of sampling locations.
   Further,  photos can facilitate potentially
   responsible party (PRP) searches and
   enforcement activities.  Recent aerial
   photography may reveal burial outlines,
   staining, or stressed vegetation.  In one
   instance, aerial photos  of a landfill pinpointed
   locations of buried drums more precisely than
   did borings.  In another instance,  aerial photos
   of two adjacent oilfield-related sites revealed
   the possibility of burled waste pits.
   Subsequent samples from the locations
   confirmed the  existence of the waste pits.
   Whenever possible, use aerial photographs to
   help delineate  site contamination, aid in
   enforcement, and save money by narrowing
   the areas that  must be  sampled.
Summary

Surfirial soil and other source samples may be used to
establish  observed contamination for the soil exposure
pathway.  Observed contamination  can be documented
only by chemical analysis.  Direct observation and the
potential  for observed contamination are not evaluated
for this pathway. Sample on the property, within 200 feet
of targets, and within two feet of the source  surface.
Multiple  samples which  meet the  HRS criteria  for
observed contamination may be used to delineate an area
of observed contamination by inferring contamination
between  sampling points.   The  scope  of  the  Site
Inspection generally does not warrant fully delineating
areas that are not subject to observed  contamination.
The  primary objective is to identify targets  that  may
come in contact  with hazardous substances at the site.
Whenever possible, select sampling locations which serve
the dual purpose of establishing observed contamination
and identifying targets.
References

1.  U.S.  Environmental  Protection  Agency,   1992.
    Guidance for Performing Site  Inspections  Under
    CERCLA.  Office of Solid Waste and Emergency
    Response.  Directive 9345.1-05.

2.  U.S.  Environmental  Protection  Agency,   1992.
    Hazard Ranking System Guidance Manual. Office of
    Solid Waste  and  Emergency Response.   Directive
    9345.1-07.

3.  U.S. Environmental Protection Agency, 1993. Data
    Quality Objectives Process for  Superfund, Interim
    Final Guidance. Office of Emergency and Remedial
    Response. Directive 9355.9-01.

4.  U.S.  Environmental   Protection  Agency,   1990.
    Hazard Ranking System,  Final Rule. 40  CFR Part
    300.

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                                   Additional copies can be obtained from:

                                National Technical Information Service (NTIS)
                                       U.S. Department of Commerce
                                           5285 Port Royal Road
                                           Springfield, VA 22161
                                              (703) 487-4650
                                             Order #94-963312
United States
Environmental Protection Agency
5204G
Washington, DC 20460

$300 Penalty for Private Use

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APPENDIX B
  Acronym List
     and
   Glossary

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                                      ACRONYM LIST

AALAC      ambient aquatic life advisory concentration
AOC         area of observed contamination
AWQC       ambient water quality criteria
BCF         bioconcentration factor
BCFV        bioconcentration factor value
BIA          Bureau of Indian Affairs
BLM         Bureau of Land Management
BPF         bioaccumulation potential factor
BPFV        bioaccumulation potential factor value
STAG        Biological Technical Assistance Group
CA          cooperative agreement
CERCLA      Comprehensive Environmental Response, Compensation and Liability Act
CERCLIS     Comprehensive Environmental Response, Compensation and Liability Information System
CERI         Center for Environmental Research Information
CFR         Code of Federal Regulations
CLP         Contract Laboratory Program
CRDL        contract-required detection limit
CRQL        contract-required quantitation limit
CWA         Clean Water Act
ODD         dichloro-diphenyl-dichloro-ethane
DOE         dichloro-diphenyl-ethane
DDT         dichloro-diphenyl-trichloroethane
DL          detection limit
DNAPL       dense nonaqueous phase liquid
DOD         U.S. Department of Defense
DOE         U.S. Department of Energy
DOT         U.S. Department of Transportation
EECA        engineering evaluation/cost analysis
EIS          environmental impact statement
EP          extraction procedure
EPA          U.S. Environmental Protection Agency
ERCS        Emergency Response Cleanup Services
ERD         Emergency Response Division
ERT          Environmental Response Team
FDAAL       Food and Drug Administration advisory level
FRDS        Federal Data Reporting System
FWRS        Fish and  Wildlife Reference Service
GIS          Geographic Information System
GW          ground water
HASP        health and safety plan
HFC         human food chain
HRS         Hazard Ranking System
HRSGM      Hazard Ranking System Guidance Manual
HWQ        hazardous waste quantity
IAG          interagency agreement
IDL          instrument detection limit
IDW         investigation-derived waste
LNAPL       light nonaqueous phase liquid
LR           likelihood of release
                                                                                 Acronym Ust
                                                                                 pag* 1

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                                      ACRONYM LIST
MCL         maximum contaminant level
MCLG        maximum contaminant level goal
MDL         method detection limit
MMS        Minerals  Management Service
NAAQS      National Ambient Air Quality Standards
NAWDEX     National Water Data Exchange
NCP         National Contingency  Plan
NESHAP      National Emission Standard for Hazardous Air Pollutants
NFRAP       no further remedial action planned
NMFS        National Marine fisheries Service
NOAA        National Oceanic and Atmospheric Administration
NPDES       National Pollutant Discharge Elimination System
NPL         National Priorities List
NPS         National Park Service
NRC         Nuclear Regulatory Commission
NRT         National Response Team
NSFF        National Sport Fishing Federation
NWI         National Wetlands Inventory
ORP         EPA Office of Radiation Programs
OSC         Onscene  Coordinator
OSM         Office of  Surface Mining
OSWER      Office of  Solid Waste and Emergency Response
OVA         organic vapor analyzer
OWRS        Office of  Water Regulations and Standards
PA           preliminary assessment
PCB         polychlorinated biphenyl
PPE         probable  point of entry
PRP         potentially responsible party
QA          quality assurance
QC          quality control
RA          removal action
RAS         Routine Analytical Services
REAC        Regional  Engineering Analytical Contract
RCRA        Resource Conservation and Recovery Act
RDT         Regional  Decision Team
RI/FS        remedial investigation/feasibility study
RREL        Risk Reduction Engineering Laboratory
RRT         Regional Response Team
SACM        Superfund Accelerated Cleanup Model
SARA        Superfund Amendments and Reauthorization Act
SAS         Special Analytical Services
SAV         submerged aquatic vegetation
SC          screening concentration
SCDM        Superfund Chemical Data Matrix
SCS         Soil Conservation Service
SDWA        Safe Drinking Water Act
SF           slope factor
SI           site inspection
SMO         sample management officer
SQL         sample quantitetion limit
SW          surface water
SWDA        Solid Waste Disposal Act
                                                                                  Acronym List
                                                                                  pap* 2

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                                     ACRONYM LIST
TAL          target analyte list
TAT          Technical Assistance Team
TCL          target compound list
TCLP         Toxic Characteristic Leaching Procedure
TDL          target distance limit
TSCA        Toxic Substances Control Act
TSOF        treatment storage, or disposal facility
USC         U.S. Code
USDA        U.S. Department of Agriculture
USFS         U.S. Forest Service
USFWS      U.S. Fish and Wildlife Service
USGS         U.S. Geological Survey
UV           ultraviolet
WC           waste characteristics
WHPA         wellhead protection area
                                                                                   Acronym List

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                                       GLOSSARY
Apportioned population:  In the evaluation of drinking water target populations associated with a
blended system, that portion of the population evaluated as being served by an individual well or
intake within the system.

Aquifer:  A saturated subsurface zone from which drinking water is drawn.

Blended system:  A drinking water supply system which can or does combine (e.g., via connecting
valves) water from more than one well or surface water intake, or from a combination of wells and
intakes.

CERCLA:  Comprehensive Environmental Response, Compensation, and Liability Act of 1980.

CERCLA Information System:  CERCLIS, EPA's computerized inventory and tracking  system for
potential hazardous waste sites.

CERCLIS:  CERCLA Information System.

Coastal tidal waters:  Surface water body type that includes embayments, harbors, sounds,
estuaries, back bays, etc. Such water bodies are in the interval seaward from the mouths of rivers
and landward from the 12-mile baseline marking  the transition to the ocean water body type.

Comprehensive Environmental Response. Compensation, and Liability Act of 1980:  Legislation that
established the Federal Superfund for response to uncontrolled releases of hazardous substances to
the environment.

Contaminated  soil: Soil onto which available evidence indicates that a hazardous substance  was
spilled, spread, disposed, or deposited.

Depth to aquifer:  The vertical distance between  the deepest point at which hazardous substances
are suspected  and the top of the shallowest aquifer that supplies drinking water.

Distance to surface water: The shortest distance that runoff would follow from  a source to surface
water.

Drinking water population: The number of residents,  workers, and students who drink water drawn
from wells or surface water intakes located within target distance limits

Drums:  Portable containers designed to hold a standard 55-gallon volume of wastes.

Emergency response: See "removal."

Factor:  The basic element of site  assessment requiring data collection and evaluation for scoring
purposes.

Factor  category:  A set of related factors. Each  pathway consists of three factor categories --
likelihood of release or exposure, targets, and waste characteristics.

Federal Register:  Daily  publication of the Government Printing Office; contains public notices,
rules, and regulations issued by the Federal Government. Cited as "  FR  ."
                                                                                          Glossary
                                                                                           page 1

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      FEMA:  Federal Emergency Management Agency.

      Fishery:  An area of a surface water body from which food chain organisms are taken or could be
      taken for human consumption on a subsistence, sporting, or commercial basis. Food chain
      organisms include fish, shellfish, crustaceans,  amphibians, and amphibious reptiles.

      FR:  Federal Register.

      GEMS:  Geographical Exposure  Modeling System.

      Geographical Exposure Modeling System:  Population database maintained by EPA's Office of Toxic
      Substances; provides residential populations in specified distance rings around a point location.

      Hazard Ranking System:  EPA's principal mechanism for placing sites on the  NPL.

      Hazardous constituent:  Hazardous substance.

      Hazardous substance:  Material  defined as a hazardous substance,  pollutant, or contaminant in
      CERCLA Sections 101(14) and  101(33).

      Hazardous waste:  Any material suspected to  contain a hazardous  substance, pollutant, or
      contaminant that is or was in a  source.

      HRS: Hazard Ranking System.

      Karst:  A kind of terrain with characteristics of relief and drainage arising from a high degree of
      rock solubility.  The majority of  karst conditions occur in limestone areas, but karst may also occur
      in areas of dolomite, gypsum, or salt deposits. Features associated with karst terrain may include
      irregular topography, abrupt ridges, sinkholes, caverns, abundant springs, disappearing  streams,
      and a general lack of a well-developed surface drainage system of  tributaries and streams.

      Lake: A type of surface water body which includes:

           •  Natural and artificially-made lakes or ponds that lie along rivers or streams (but  excluding
              the Great Lakes).

           •  Isolated but perennial lakes, ponds, and wetlands.

           •  Static water channels or oxbow lakes  contiguous to streams or rivers.

           •  Streams or small rivers, without diking, that merge into surrounding perennially-inundated
              wetlands.

           •  Wetlands contiguous to water bodies  defined as lakes are  considered to be part of the lake.

      Landfill:  An engineered (by excavation or construction) or natural  hole in the ground into which
      wastes  have been  disposed by  backfilling, or  by contemporaneous soil deposition with  waste
      disposal, covering wastes from view.

      Land treatment: Landfarming or other land treatment method of waste management in which liquid
      wastes  or sludges are spread over land and tilled,  or liquids are injected at shallow depths into
      soils.
Glossary
page 2

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National Contingency Plan:  Regulation that establishes roles, responsibilities, and authorities for
responding to hazardous substance releases. The NCP established the HRS as the principal
mechanism for placing sites on the NPL.

National Priorities List:  Under the  Superfund program, the list of releases and potential releases of
hazardous substances, pollutants,  and contaminants that appear to pose the greatest threat to
public health, welfare, and the environment.

NCP:  National Oil and Hazardous  Substances Pollution Contingency Plan, commonly known as the
National Contingency Plan.

NFRAP: No further remedial action planned; site disposition decision that further response under
the Federal Superfund is not necessary.

No suspected release: A professional judgement conclusion based on site and pathway conditions
indicating that a  hazardous substance is not likely to have been released to the environment.  (No
suspected release is the PA term analogous to the HRS "potential to release.")

NPL:  National Priorities List.

Ocean:  A type of surface water body which includes:

    •  Ocean areas seaward from a baseline distance of 12 miles from shore.
    •  The Great Lakes, along with wetlands contiguous to them.

PA: Preliminary  assessment.

PA-Score:  EPA's computer program that automates PA site scoring.

Pathway:  The environmental medium  through which a hazardous substance may threaten targets.
The PA evaluates the migration  and threat potential through the ground  water, surface water, air,
and soil exposure pathways.

Pile:  Any non-containerized accumulation above the ground surface of solid, non-flowing wastes;
includes open dumps. Some types of  piles are:  Chemical Waste Pile --  consists primarily of
discarded chemical products,  by-products, radioactive wastes, or used or unused feedstocks;  Scrap
Metal or Junk Pile --  consists primarily of scrap metal or discarded durable goods such as
appliances, automobiles, auto parts, or batteries,  composed of materials suspected to contain or
have contained a hazardous substance; Tailings Pile --  consists  primarily of any combination of
overburden from a mining operation and tailings from a mineral mining, beneficiation, or processing
operation; Trash  Pile -- consists primarily of paper, garbage, or discarded non-durable goods which
are suspected to contain or have contained a hazardous substance.

PPE:  Probable point of entry.

Preliminary assessment: Initial stage of site assessment under Superfund; designed to distinguish
between sites that pose little  or no threat to human  health and  the environment and sites that
require further investigation.

PREscore:  EPA's computer program that  automates site scoring with the Hazard Ranking System.
                                                                                         Glossary
                                                                                           page 3

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    Primary target: A target which, based on professional judgement of site and pathway conditions
    and target characteristics, has a relatively high likelihood of exposure to a  hazardous substance.
    (Primary target is the PA term analogous to the HRS target exposed to Level I or Level II actual
    contamination.)

    Probable point of entry: The point at which runoff from the site most likely enters surface water.

    RCRA:  Resource Conservation and Recovery Act of 1976.

    Removal:  An action taken to eliminate, control, or otherwise mitigate a threat posed to the public
    health or environment due to release or threatened release of a hazardous substance. Removals
    are relatively short-term actions to respond to situations requiring immediate action.

    Resident:  A person whose place of residence (full- or part-time) is within the target distance limit.

    Resident individual: Under the soil exposure pathway, a resident or student within 200 feet of any
    area of suspected contamination associated with the site.

    Resident population: Under the soil exposure pathway, the number of residents and students
    within 200 feet of any area  of suspected contamination associated with the site.

    Resource Conservation and Recovery Act of 1976:  Legislation that established cradle-to-grave
    accountability for hazardous wastes, from point of generation to point of ultimate disposal.

    SARA:  Superfund Amendments and Reauthorization Act of 1986.

    Secondary target:  A target  which, based on professional judgement of site and pathway conditions
    and target characteristics, has a relatively low  likelihood of exposure to a hazardous substance.
    (Secondary  target is the PA term analogous to the HRS target exposed to potential contamination.)

    Sensitive environment:  A terrestrial or aquatic resource, fragile natural setting, or other area with
    unique or highly-valued environmental or cultural features.

    Si: Site inspection.

    Site:  The area consisting of the aggregation of sources,  the  areas between sources, and areas that
    may have been contaminated due to migration from  sources; site boundaries are independent of
    property boundaries.

    Site inspection:  Second stage of site assessment under Superfund, conducted on sites that receive
    a further action recommendation after the PA;  builds on PA information and typically includes
    sampling to identify hazardous substances,  releases, and  contaminated targets; identifies sites that
    pose the greatest threats to human health and the environment.

    Source:  An area where a hazardous substance may have been deposited, stored, disposed, or
    placed. Also, soil that may have become contaminated as a result of hazardous substance
    migration.  In general,  however, the volumes of air,  ground water, surface water, and surface
    water sediments that may have become contaminated through migration are not  considered
    sources.

    Stream flow:  The average rate of  flow of a water body, expressed in cubic feet per second (cfs).
Glossary
page 4

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Stream or river:  A type of surface water body which includes:

     •  Perennially-flowing waters from point of origin to the ocean or to coastal tidal waters,
       whichever comes first, and wetlands contiguous to these flowing waters.

     •  Aboveground portions of disappearing rivers.

     •  Artificially-made ditches only insofar as they perennially flow into other surface water.

     •  Intermittently-flowing waters and contiguous intermittently-flowing ditches in areas where
       mean annual precipitation is less than 20 inches.

Student:  A full- or part-time attendee of a daycare facility or educational institution located within
the target distance limit.

Superfund Amendments and Reauthorization Act of 1986: Legislation which extended the Federal
Superfund program and mandated revisions to the MRS.

Surface impoundment: A topographic depression, excavation, or diked area, primarily formed from
earthen materials (lined or unlined) and designed to hold accumulated liquid wastes,  wastes
containing free liquids, or sludges that were not backfilled or otherwise covered during periods of
deposition; depression may be dry if deposited liquid has evaporated, volatilized or leached, or wet
with exposed liquid; structures that may be more specifically described as  lagoon pond, aeration
pit, settling pond, tailings pond, sludge pit, etc.;  also a surface impoundment that has been covered
with soil  after the final deposition of waste materials (i.e., buried or backfilled).

Surface water: A naturally-occurring, perennial water body;  also, some artificially-made and/or
intermittently-flowing  water bodies.  See "water body type"  and subsequent definitions for more
detail.

Suspected  release:  A professional judgement conclusion based on site and pathway conditions
indicating that a hazardous substance is likely to have been  released to the environment.
(Suspected release is  the PA term analogous to the MRS "observed release.")

Tanks and non-drum containers: Any stationary device, designed to contain accumulated wastes,
constructed primarily of fabricated materials (such  as wood,  concrete, steel, or plastic) that provide
structural support; any portable or mobile device in  which waste is stored  or otherwise handled.

Target:  A physical or environmental receptor that is within the target distance limit for a particular
pathway. Targets may include wells and surface water intakes supplying  drinking water, fisheries,
sensitive environments, and resources.

Target distance limit:  The maximum distance over which targets are evaluated.  The target
distance  limit varies by pathway: ground water and air pathways -- a 4-mile radius around the site;
surface water pathway -- 15 miles downstream from the probable  point of entry to surface water;
soil exposure pathway - 200 feet (for the resident population threat) and  1 mile (for the nearby
population threat) from areas of known  or suspected contamination.

Target population:  The human  population associated with the site and/or  its targets. Target
populations consist of those people who use target wells or  surface water intakes supplying
drinking water, consume food chain species taken  from target fisheries, or are regularly present on
the site or within target distance limits.
                                                                                           Glossary
                                                                                            page 5

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      Terrestrial sensitive environment: A terrestrial resource, fragile natural  setting, or other area with
      unique or highly-valued environmental or cultural features.

      USF&WS:  U.S.  Fish and Wildlife Service.

      USGS:  U.S. Geological Survey.

      Water body type:  Classification  of a surface water body.  Water body  types include:  streams and
      rivers; lakes; oceans (includes the Great Lakes); and coastal tidal waters.  See the specific
      definition of each water body type for more detail.

      Wetland: A type of sensitive environment characterized as an area that is sufficiently inundated or
      saturated by surface or ground water to support vegetation adapted for life in saturated soil
      conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.

      Worker: Under the soil exposure pathway, a person who is employed on a full- or part-time basis
      on the property on which the site is located.  Under all other pathways, a  person whose place of
      full- or part-time employment is within the target distance limit.
               Guidance for Performing Preliminary Assessments Under CERCLA, USEPA, Sept. 1991
Glossary
page 6

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APPENDIX C
  Case Studies

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         SOURCE SAMPLING EXERCISE:  ACME MANUFACTURING COMPANY
OBJECTIVE:
      Using available site information, develop a source sampling strategy implementing
      procedures established in the SI guidance manual.
METHOD:
      1.  Review the general site information provided below.
      2.  Identify site sources on the map.
      3.  Develop a source sampling strategy that includes source characterization,
         background determination, and collection of quality control samples. You are limited
         to 20 samples.  You do not need to use all available samples.
      4.  Record your sampling strategy on the table provided.
      5.  BONUS CHALLENGE: Complete this exercise using only 10 samples.
General Site Information:

      • The ACME Manufacturing Company site is an inactive electroplating facility. The total
       acreage is about 10 acres (see site map).
      • Rinsewater from the electroplating process was discharged to treatment ponds from
       1907 until 1985.
      • Drums, which were located in the former drum storage area found on the
       northwestern comer of the facility property, are believed to have contained waste
       solvents. They were held there prior to offsite removal.
      • Stained soil was observed adjacent to the bulk chemical unloading area and
       manufacturing building.
      • The waste pile appears to be dried sludge from the treatment ponds.
      • The landfill reportedly received "off-spec" products, spent solvents, and treatment
       pond sludge.
      • Leachate seeps were observed along the southeast comer of the landfill with
       stressed vegetation extending beyond the facility boundary.
Cam Studios
pageC-2

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       Source Sampling Exercise
           Former
           Drum
           Storage
           Area
                    ACME
                    Manufacturing
                    Company
            Facility Boundary
            Stressed Vegetation
           3 Stained Soil
           -• Drainage Ditch
-o «
to 
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SITE NAME:
                        SOURCE SAMPLING STRATEGY
        Sample ID
Sample Type
Rationale
Total Samples:

Special Sampling Considerations:
C«$« Stud/as
pageC-4
                                                                        11/94

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                    BONUS SOURCE SAMPLING STRATEGY
SITE NAME:
        Sample ID
Sample Type
Rationale
Total Samples:

Special Sampling Considerations:
11/94
                                    Casa Studios
                                       pageC-5

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           SURFACE WATER SAMPLING EXERCISE: R. R. ACME LANDFILL
OBJECTIVE:
      Using available site information, develop a single SI sampling strategy to test a PA
      hypothesis of suspected contamination of surface water.
METHOD:
      1.  Review the general site information and map below.
      2.  Identify site sources on the map.
      3.  Identify probable points of entry (PPE).
      4.  Identify all primary and secondary targets.
      5.  Develop a sampling strategy to test the PA hypothesis of suspected release to
         surface water. You should use the procedures outlined in the SI guidance to
         demonstrate observed contamination. Because this is a single SI, all data must be
         sufficient to complete MRS scoring and documentation.
      6.  You are limited to 20 samples. You do not need to use all available samples.
      7.  Record your sampling strategy on the table provided.
      8.  BONUS CHALLENGE: Develop a sampling strategy to demonstrate actual
         contamination.
General Site Information:

      • The R. R. Acme Landfill is a municipal landfill that was active between 1950 and
       1980.
      • The PA has determined that the surface water pathway is the major pathway of
       concern for this site.
      • The PA has determined that the hazardous substances of concern are DDT, lead, and
       mercury.
      • Critical distances:
       - PPE to wetland = 200 feet
       - PPE to wilderness area and habitat = 0.5 miles
       - PPE to intake = 5 miles
Cut Studios
pageC-6

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     Sample to Test Suspected Contamination
       Drainage
       Ditch

                                         Habitat for
                                         Federally Designated
                                        ^ Endangered Species
                                                Intake
                                                    1.200 els
•

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                             SAMPLING STRATEGY
SITE NAME:
        Sample ID
Sample Type
Rationale
Total Samples:

Special Sampling Considerations:
Case Stud/as
pageC-8
                                                                          11/94

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                         BONUS SAMPLING STRATEGY
SITE NAME:
        Sample ID
Sample Type
Rationale
Total Samples:

Special Sampling Considerations:
11/94
                                    Caso Studios
                                        pageC-9

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CASE STUDY: SI SAMPLING STRATEGY

OBJECTIVE:

      Using available site information for the Wolfram Industries site, develop a SI sampling
      strategy implementing procedures established in the SI guidance manual.

METHOD:

      1.  Review the site information provided with this case study.  The information is
         derived from the preliminary assessment (PA).

      2.  Identify the following elements and label them on the appropriate maps:
         - Sources
         - Targets
         - Areas of suspected contamination
         -PPE
         - In-water portion of the surface water pathway

      3.  Develop a list of objectives for an SI sampling plan

      4.  Develop a sampling strategy to test the following hypotheses:
         - Suspected release to ground water, surface water, and air
         - Suspected soil contamination
         - Exposure of targets to contaminated ground water, surface water, soil, and air

      5.  Include the following elements in the sampling strategy:
         - Characterization of background
         - Demonstration of attribution
         - Quality control (minimal)

      6.  There is a limit of 20 samples for this exercise. You are not required to use all
         allocated samples.

      7.  Plot all sampling locations on the site map(s).

      8.  Complete the sampling strategy table.
Cam Studios                                                                      11/94
page C-10

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SITE INSPECTION CASE STUDY: WOLFRAM INDUSTRIES
General Site Description

Wolfram Industries is a 12-acre site located within an industrial area in Harbor Hill County,
Fairlawn, New York. It consists of a laboratory, a warehouse, and a refinery. The site was
active from 1941 to 1989 and has since been abandoned.  The Mosquito River is located east
of the site and flows south into Harbor Hill Bay. There are several small wetlands along the
banks of the Mosquito River.  A potato farm occupies a piece of land to the east of the river.
Rainfall for this area is approximately 28 inches per year, according to the local weather
station records.

The GEMS data base provides the following population information for the region lying within
4 miles of the site.
Distance from Site
Onsite
0 - % mile
1/4 - % mile
!* - 1 mile
1-2 miles
2-3 miles
3-4 miles
Population
0
250
1,080
4,520
9,900
35,400
67,900
U.S. Census Bureau data for this region indicate an average 2.5 people per household.

Operational History

A review of site records indicates that this facility processed raw tungsten ore into tungsten
metal via crushing and hydrochloric acid extraction and precipitation reactions.  Processed
tungsten was used for making lighting filaments and for making other tungsten compounds.
Waste products include acidic metallic slag that contains high concentrations of hexavalent
chromium, lead, zinc, manganese, iron, copper, and cyanide.
11/04
CM* Studies
   pageC-11

-------
Information obtained during the PA revealed several possible source areas onsite  (see Figure
1, Wolfram Industries site map). The slag is stored in stacked 55-gallon drums throughout the
site. The outdoor portions of the site are not paved. Two large piles of fine-grained black ore
tailings are adjacent to the refining facility. They are estimated to contain 375 cubic yards of
waste within an estimated combined area of 416 square feet. A plastic-lined lagoon of
unknown depth is found to the north of the refinery. It occupies an area of 2,000 square feet.
The lagoon was reported to contain process waters and acidic solutions containing heavy
metals and cyanide. Plants were observed growing out of a portion of the lagoon.  Three
monitoring wells that are 75 feet in depth are located around the lagoon. One downgradient
monitoring well was reported to be vandalized and filled in with beer cans and gravel.  The
facility is fenced on three sides, but there is a large hole in the southern fence due to a recent
automobile accident.

Probable Substances of Concern

Based on observations made during the offsite reconnaissance for the PA, the 55-gallon
drums of slag are badly deteriorated and the contents of several drums are spilling black
powdery slag onto the ground.  Partially corroded drums were found on the north side of the
warehouse; their contents are unknown. A topographic map of the area shows that the site
slopes toward the northeast, and it is documented that runoff from the site is directed into the
Mosquito River through an outfall pipe. The soil between the outfall pipe and the river was
stained green and is devoid of vegetation. Aerial photographs of the site and information
gathered during the PA indicate that there are 4,321 drums located outdoors. There is no
containment and these drums are in contact with the unpaved ground. The  area of stained
soil adjacent to the drums is estimated to be 400 feet by 600 feet. The area of contaminated
soil near the outfall is estimated to be 100 feet long by 10 feet wide.  The estimated depth of
the contaminated soil for both areas is 0.5 feet. The combined volume of the two tailings piles
is estimated to be 375 cubic yards with a surface area of 416 square feet.

Geology and Ground Water

Based on information gathered from a United States Geological Survey (USGS) publication,
the native soil for the site and surrounding area is a thin (0 to 2 feet thick) cover of loamy soil.
Beneath this soil lies a thick formation of sand and gravel that is part of the Atlantic Coastal
Plain from the Cretaceous  Period.  A water table aquifer occurs at a depth of 60 feet below the
surface, although perched  water tables exist over small and discontinuous clay lenses at
shallow depths (about 10 feet) throughout the area.  Ground water flow in the vicinity of the
site is known to flow east-southeast or toward the Mosquito River.
Cast Studies
page C-12

-------
                      Figure 1: Wolfram Industries Site Map
                 (Drums)
              000000
                                                     (Vandalized)
               Warehouse
                                       Heavy
                                     equipment
                                      storage
                                                                 Potato
                                                                  farm
                           Large drum dump
                              Stained soil
     N
11/94
CastStud/0s
  pageC-13

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Ground Water Pathway

According to the municipal water authority, potable water for residents within 4 miles of the site
comes from water reservoirs located 5 miles from the site.  A wellhead protection area does
not exist for this region. However, according to a USGS ground water data base, some
residents have their own potable wells screened within a confined sand aquifer at a depth of
300 feet. Groundwater from a shallow perched water table aquifer is used for the irrigation of
Mr. Spuds 4.5-acre potato farm.  Some residents are supplied by ground water. They are
eight homes located 0.3 miles from the site and 44 homes at 3.75 miles. This information was
obtained from a USGS computer listing of wells within the  county. No information is available
on any well closures due to site contamination.

Surface Water Pathway

The Mosquito River was identified on the topographic map as the closest surface water body
to the site.  It lies within 100 feet of the site. Based on information gathered during the offsite
reconnaissance, an outfall pipe from the facility and its associated stained soil area lie
adjacent to the river bank. The bank of this river is located several feet below the grade of the
site. The Federal Emergency Management Agency (FEMA) indicates that the site is located
on the 10-year flood plain. On average, the Mosquito River flows at 1,500 cubic feet per
second, according to the USGS Water Resource Atlas for this region. The state fish and
wildlife bureau has confirmed that portions of this river serve as a fishery for catfish and small-
mouth bass and as a habitat for the state-designated endangered species known as the "long-
eared sunfish." In addition, many sport saltwater fish are caught in Harbor Hill Bay located 3
miles to the south. One unmapped wetland (0.1 miles in length) was observed along the river
closest to the site and another (0.4 miles in length) was identified from published wetlands
maps.  No known drinking water intakes are located on the Mosquito River.

Soil Exposure Pathway

The PA states  that there are no residents, schools, or day care centers located on or within
200 feet of an area of observed soil contamination. A hole in the fence of the facility allows
unauthorized access by children or others.  There are no terrestrial sensitive environments
located on any areas of observed contamination. The total population within 1 mile of the site
is 5,850 (based on GEMS data).

Air Migration  Pathway

The nearest residence is  located 0.24 miles west of the site  and prevailing winds come from
the west. No windbreak or covering is associated with the tailings piles.
Cm Studies                                                                       11/94
pageC-14

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                         Figure 2: Surface Water Pathway Map
                      Site
                                     Extent of salt water
                                                        t
                                                        N

                                                       = fishery

                                                   Not to Scale
                        15-mile target
                        distance limit
                       Harbor Hill Bay
4/94
Case Studies
   page C-15

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                             SI SAMPLING STRATEGY
           Sample ID
Sample Type
Rationale
Total Samples:

Special Sampling Considerations:

Requested Analyses:
Caso Stud/as
page C-16
                                                                            11/94

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                             SI SAMPLING STRATEGY
           Sample 10
Sample Type
Rationale
Total Samples:

Special Sampling Considerations:

Requested Analyses:
11/94
                                   Case Sfucf/as
                                      pageC-17

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APPENDIX D
 SI Data Summary

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                             SI DATA SUMMARY
The investigator may use the SI Data Summary to compile analytical data and non-sampling
information concerning the site.  The Data Summary can be a checklist to:

              Summarize previous and newly-collected information
              Identify factors that have not been fully evaluated
              Focus additional data collection efforts

A completed SI Data Summary may facilitate entering data into PREscore or other SI scoring
and MRS documentation tools.

Responses on the SI Data Summary need not be typed; legible handwriting is acceptable.

The Data Summary is not a mandatory requirement for SI reporting; EPA Regional guidelines
may recommend using other mechanisms to summarize information collected during the SI or
to compile previous information about the site.

SI Data Summary entries marked with an asterisk (*) are optional during a focused SI.  For
pathways investigated during an expanded SI, all Data Summary entries should be completed.

If  necessary, continuation pages to summarize  additional  analytical results should be
photocopied and included with the Data Summary. A sample location map should be provided
or referenced for all analytical results.

The last page of  the Data Summary may be  used to describe additional site information
regarding a specific data element.  In addition, this page may be used to describe or summarize
site information that has not been collected, is not available, or is not well documented.

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SI Data Summary
Site Name	
                            Site Name
                                   EPA Region,
                                       Date
Contractor Name or State Office and Address
                        GENERAL SITE INFORMATION
1.  CERCLIS ID No.
    Address 	
    County	
                              City.
State
Zip Code.
Congressional District
2.  Owner name
                      Operator name
    Owner address
    City	
    State
         Operator address
         City	
              State
3.  Type of ownership (check all that apply):
    D Private  D Federal/Agency	
    D Other	
                         D State  D County  D Municipal
                                      Reference(s)	
4.  Approximate size of property:	acres
5.  Latitude              	"  Longitude
 6.  Site status:   Q Active  D Inactive D Unknown
 7.  Years of operation:  From:	to:	D Unknown
 8.  Previous Investigations:  .
    Type        Agencv/State/Contractor             Date
                                      Reference(s).
                                      Reference(s)
                                      Reference(s)
                                      Reference(s)
                                                               Reference(s).
                                                               Reference(s).
                                                               Reference(s).
                                                               Reference(s).
                                                               Reference(s)
                                                               Reference(s)

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SI Data Summary                                     Site Name
                      WASTE SOURCE INFORMATION
1.  Waste source types (check all that apply)
   D Constituent
   D Wastestream (type)
   D Landfill
   D Drums
   D Contaminated soil
   D Land treatment
   D Tanks or non-drum containers (type)
   n Pile (type)	
   D Surface impoundment (buried)
   D Surface impoundment (backfilled)
   D Other	

   Reference(s)   	;	
2.  Types of wastes (check all that apply)

   D Organic chemicals
   D Inorganic chemicals
   D Municipal wastes
   D Radionuclides
   D Metals
   D Pesticides/Herbicides
   D Solvents
   D Other	
    Reference(s)
3.  Summarize history of waste disposal operations:
    Reference(s)

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SI Data Summary                                         Site Name
4.   Source characterization (Attach pages to show quantity and calculations.)


    Source 1  name:	        Source type_

    Describe  source:       	
    Ground water migration containment:

    Surface water migration containment:
    Air migration (gas and migration) containment:
    Physical state of wastes:  D Liquid  D Solid  D Sludge/Slurry  D Gas  D Unknown
    Constituent quantity of hazardous substances:         	(specify units)
    Wastestream quantity containing hazardous substances:         	(specify units)
    Volume of source (yd3):	       Area of source (ft2):	

    Hazardous substances associated with source 1:
    Reference(s)
    Source 2 name:  	           Source type_

    Describe source:       	
    Ground water migration containment:

    Surface water migration containment:
    Air migration (gas and migration) containment:
    Physical state of wastes:  D Liquid  D Solid  D Sludge/Slurry  D Gas  D Unknown
    Constituent quantity of hazardous substances:         	(specify units)
    Wastestream quantity containing hazardous substances:        	(specify units)
    Volume of source (yd3):	       Area of Source (ft2):	

    Hazardous substances associated with source 2:
     Reference(s)

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SI Data Summary                                        Site Name	

CONTINUATION PAGE FOR SOURCE CHARACTERIZATION


    Source #	Name	       Source type

    Describe source:       	   	
    Ground water migration containment:

    Surface water migration containment:
    Air migration (gas and migration) containment:
    Physical state of wastes:  D Liquid  D Solid  D Sludge/Slurry  D Gas  D Unknown
    Constituent quantity of hazardous substances:         	(specify units)
    Wastestream quantity containing hazardous substances:        	(specify units)
    Volume of source (yd3):	       Area of source (ft2):	

    Hazardous substances associated with source #	:
    Reference(s)
    Source #	Name	      Source type

    Describe source:      	
    Ground water migration containment:

    Surface water migration containment:
    Air migration (gas and migration) containment:
    Physical state of wastes: D Liquid  D Solid  D Sludge/Slurry  D Gas  D Unknown
    Constituent quantity of hazardous substances:        	(specify units)
    Wastestream quantity containing hazardous substances:         	(specify units)
    Volume of source (yd3):	        Area of source (ft2):	

    Hazardous substances associated with source #	:
     Reference(s)

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SI Data Summary                                        Site Name	

5.  Description of removal or remedial activities

    If a removal has occurred, identify the removal authority and describe the activities. Specify the
    date(s) of the removal.
     Reference(s)

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SI Data Summary                                      Site Name
                       GROUND  WATER INFORMATION
1.  Ground water drinking water use within 4 miles of site sources:
   D Municipal    D Private   D Both    D No Drinking Water Use
   Reference(s)
2.  Is ground water contaminated?
   D Yes D No  D Uncertain but likely  D Uncertain but not likely
   D Additional sampling required
   Is analytical evidence available?    D Yes  D No              Reference(s)

3.  Is ground water contamination attributable to the site?
   D Yes D No  D Additional sampling required                Reference(s)
4.  Are drinking water wells contaminated?
    D Yes D No  D Uncertain but likely  D Uncertain but not likely
    D Additional sampling required
    Is analytical evidence available?    D Yes  D No              Reference(s)
5.*  Net precipitation (HRS Section 3.1.2.2):	inches        Reference(s)	

6.  County average number of persons per residence:	Reference(s)	

7.  Discuss general stratigraphy underlying the site. Attach sketch of stratigraphic column.
    Reference(s)
 8.  Using Table GW-1 (next page), summarize geology underlying the site (starting with formation
    #1 as closest to ground surface). Indicate if formation is interconnected with overlying formation.

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SI Data Summary
                         Site Name

TABLE GW-1:  SITE GEOLOGY
NAME OF FORMATION
1.
2.
3.
4.
5.
6.
INTER-
CONNECT?
(yes/no)






TYPE OF
MATERIAL






AVERAGE
THICKNESS
(FEET)






HYDRAULIC
CONDUCTIVITY
(CM/SEC)






USED FOR
DRINKING
WATER?






    Reference(s)
9.  Does a karst aquifer underlie any site source?
    DYes  DNo
10. Depth to top of aquifer:
    feet
Elevation:
Reference(s)

Reference(s)
11. In the table below, enter the number of people obtaining drinking water from wells located
    within 4 miles of the site. For each aquifer, attach population calculation sheets.  Key aquifer to
    formations listed in Table GW-1.
               POPULATION SERVED BY WELLS WITHIN DISTANCE CATERGORIES BY AQUIFER
DISTANCE OF WELL(S)
FROM SITE SOURCES
1/4 mile or less
>1/4 to 1/2 mile
>1/2 to 1 mile
>1 to 2 miles
>2 to 3 miles
>3 to 4 miles
AQUIFER A: INCLUDES
FORMATIONS






AQUIFER B: INCLUDES
FORMATIONS






AQUIFER C: INCLUDES
FORMATIONS






    Reference(s)
 12. Is ground water from multiple wells blended prior to distribution?
    DYes DNo                                           Reference(s)

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SI Data Summary                                        Site Name
 13.    Is ground water blended with surface water?
   DYes  DNo                                           Reference(s)
Briefly describe:
14. Distance from any Incompletely contained source available to ground water to nearest
   drinking water well (HRS Section 3.3.1):      	feet             Reference(s)	
15.  Briefly describe standby drinking water wells within 4 miles of sources at the site:
    Reference(s)
16. Using Table GW-2, summarize ground water analytical results for all sampling Investigations.
    Include and identify background ground water sample results.

17.* Ground water resources within 4 miles of site sources (HRS Section 3.3.3):
    D Irrigation (5-acre minimum) of commercial food or commercial forage crops
    D Commercial livestock watering
    D Ingredient in commercial food preparation
    D Supply for commercial aquaculture
    D Supply for major or designated water recreation area, excluding drinking water use
    D Water usable for drinking water but no drinking water wells are within 4 miles
    D None of the above

    Reference(s)       	

18. Wellhead protection area (WHPA) within 4 miles of site sources (HRS Section 3.3.4):
    D Source with non-zero containment factor value lies within or above WHPA
    D Observed ground water contamination attributable to site source(s) lies within WHPA
    D WHPA lies within 4 miles of site sources
    ID None
    Reference(s)
Additional ground water pathway description:
 References(s)
                                              10

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TABLE GW-2: ANALYTICAL RESULTS FOR GROUND WATER PATHWAY
SAMPLE ID
&DATE












TYPE OF WELL
D Irrigation O Monitoring
O Drinking water
People served
n Other
O Irrigation D Monitoring
D Drinking water
People served 	
n Other
D Irrigation n Monitoring
D Drinking water
People served 	
O Other 	
D Irrigation D Monitoring
D Drinking water
People served
n Other
D Irrigation a Monitoring
a Drinking water
People served 	
D Other
D Irrigation D Monitoring
O Drinking water
People served
D Other
D Irrigation D Monitoring
D Drinking water
People served 	
D Other
D Irrigation d Monitoring
O Drinking water
People served
n Other
SCREENED
INTERVAL












HAZARDOUS SUBSTANCE












CONCENTRATION
(SPECIFY UNITS)












DETECTION
LIMIT












REFERENCES













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SI Data Summary                                       Site Name
                      SURFACE WATER INFORMATION
   Complete this section of the data summary for each watershed If there are multiple
   watersheds.  Photocopy this page If necessary.

1.  Describe surface water migration path from site sources to at leas* 15 miles downstream.
   Attach a sketch of the surface water migration route.
    Reference(s)
2.  Is surface water contaminated?
    D Yes  D No  D Uncertain but likely  D Uncertain but not likely  D Additional sampling required
    Is analytical evidence available?    D Yes  D No                  Reference(s)	
3.  Is surface water contamination attributable to the site?
    D Yes D No  D Additional sampling required                    Reference(s)

4.  Floodplaln category In which site sources are located (check all that apply):
    CH-year D 10-year D 100-year  D 500-year D None             Reference(s)

5.  Describe flood containment for each source (MRS Section 4.1.2.1.2.2):

    Source #1  	 Flood containment     	

    Source #2  	 Flood containment     	

    Source #3  	 Flood'containment     	

    Source #	Flood containment    	

    Source #	Flood containment    	

    Source #	Flood containment    	

    Source #	Flood containment    	

    Reference(s)	-
 6.  Shortest overland distance to surface water from any source (HRS Section 4.1.2.1.2.1.3):
    	feet                                                 Reference(s)	
 7.* Size of drainage area (HRS Section 4.4.3):  	Acres        •  Reference(s)

                                             12

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SI Data Summary
Site Name
8.*  Describe predominant soil group within the drainage area (MRS Section 4.1.2.1.2.1.2).
    Reference(s)
9.*  2-year 24-hour rainfall (MRS Section 4.1.2.1.2.1.2):
           inches

10.'Elevation of the bottom of nearest surface water body:
       	feet above sea level

11 .'Elevation of top of uppermost aquifer:
       	feet above sea level
          Reference(s).


          Reference(s)


          Reference(s)
12. Predominant type of water body between probable point of entry to surface water and
    nearest drinking water Intake:
    D River    D Lake                                             Reference(s)	
 13. Identify all drinking water Intakes, fisheries, and sensitive environments within 15 miles
    downstream.
TARGET NAME/TYPE






WATER
BODY TYPE






DISTANCE
FROM PPE






FLOW
(CFS)






TARGET
CHARACTERISTICS1






TARGET
SAMPLED?






    'if target is a drinking water intake, provide number of people served by intake.
     If target is a fishery, provide species and annual production of human food chain organisms
        (pounds per year).
     If target is a wetland, specify wetland frontage (in  miles). Attach calculation pages.

    Reference(s)      	,	
 14. Is surface water drinking water blended prior to distribution?
    DYes  DNo                                              Reference(s)
                                               13

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SI Data Summary                                        Site Name
15.  Describe any standby drinking water Intakes within 15 miles downstream.
    Reference(s) 	
16.*Surface water resources within 15 miles downstream (MRS Section 4.1.2.3.3):
    D Irrigation (5-acre minimum) of commercial food or commercial forage crops
    H Commercial livestock watering
    D Ingredient in commercial food preparation
    D Major or designated water recreation area, excluding drinking water use
    D Water designated by the state for drinking water use but is not currently used
    D Water usable for drinking water but no drinking water intakes within 15 miles downstream
    D None of the above

    Reference(s)      	

17. Using Table SW-1, summarize surface water analytical results for all sampling Investigations.
    Include and identify background sample results.
                                               14

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                     TABLE SW-1: SUMMARY OF ANALYTICAL RESULTS FOR SURFACE WATER PATHWAY
SAMPLE ID
&DATE









SAMPLE
TYPE
D Aqueous
D Sediment
D Other
a Aqueous
D Sediment
Q Other
O Aqueous
a Sediment
D Other
a Aqueous
a Sediment
D Other
a Aqueous
G Sediment
D Other
a Aqueous
D Sediment
D Other
a Aqueous
a Sediment
D Other
a Aqueous
a Sediment
D Other
a Aqueous
aSedment
a Other
SAMPLE OBJECTIVE
a Release D Fishery
O Drinking water
D Sensitive environment
Distance from PPE
D Release D Fishery
D Drinking water
D Sensitive environment
Distance from PPE
O Release D Fishery
D Drinking water
O Sensitive environment
Distance from PPE
D Release D Fishery
D Drinking water
D Sensitive environment
Distance from PPE
O Release D Fishery
D Drinking water
D Sensitive environment
Distance from PPE
D Release D Fishery
D Drinking water
O Sensitive environment
Distance from PPE
D Release D Fishery
D Drinking water
D Sensitive environment
Distance from PPE
D Release a Fishery
D Drinking water
D Sensitive environment
Distance from PPE
O Release D Fishery
D Drinking water
D Sensitive environment
Distance from PPE
TARGET
NAME









HAZARDOUS
SUBSTANCE









CONCENTRATION
(SPECIFY UNITS)









DETECTION
LIMIT









REFERENCES









cn

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SI Data Summary                                        Site Name
                                SOIL  INFORMATION
1.  Is surtlclal or soil contamination present at the site?
   D Yes D No  D Uncertain but likely  D Uncertain but not likely
   D Additional sampling required
   Is analytical evidence available?    D Yes D No             Reference(s)	

2.  Is surflclal or soil contamination attributable to the site?
   D Yes D No  D Additional sampling required

3.  Is surflclal contamination on the property and within 200 feet of a residence, school, daycare
   center, or workplace?
   D Yes D No  D Uncertain but likely  D Uncertain but not likely
   D Additional sampling required
   Is analytical evidence available?    D Yes D No             Reference(s)	

4.* Total area of surflclal contamination (HRS Section 5.2.1.2):
   	square feet                               Reference(s)	
5.*  Attractiveness/accessibility of the areas of observed contamination (HRS Section 5.2.1.1). Check
    all that apply:

    D Designated recreational area
    D Used regularly, or accessible and unique recreational area
    D Moderately accessible with some use
    D Slightly accessible with some use
    D Accessible with no use
    D Inaccessible with some use
    D Inaccessible with no use

    Reference(s)      	

6.  Using Table SE-1, summarize analytical results detecting surflclal contamination within 200 feet
    of a residence, school, daycare center, or workplace.  Include and identify background sample
    results.

7.  Using Table SE-2, summarize analytical results detecting surflclal contamination within the
    boundary of a resource or a terrestrial sensitive environment. Include and identify background
    sample results if not listed in Table SE-1.

8.  Population within 1-mlle travel distance from site. Do not include populations from Table SE-1.
DISTANCE FROM SITE SOURCES
1/4 mile or less
>1/4 to 1/2 mile
>1/2 to 1 mile
POPULATION



    Reference(s)      	


                                               16

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TABLE SE-1:  ANALYTICAL RESULTS FOR SOIL EXPOSURE PATHWAY
SAMPLE ID
4 DATE








SAMPLE
DEPTH








TYPE OF PROPERTY
O Residence D School
D Daycare center
n Workplace
D Residence D School
O Daycare center
d Workplace
D Residence D School
D Daycare center
D Workplace
D Residence D School
D Daycare center
d Workplace
D Residence D School
a Daycare center
n Workriace
D Residence a School
D Daycare center
d Workolace
D Residence a School
D Daycare center
n Workolace
D Residence a School
D Daycare center
D Workplace
POPULATION








HAZARDOUS
SUBSTANCE








CONCENTRATION
(SPECIFY UNITS)








DETECTION
LIMIT








REFERENCES









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                             TABLE SE-2: ANALYTICAL RESULTS FOR SOIL EXPOSURE PATHWAY
SAMPLE ID
&DATE




SAMPLE
DEPTH




TYPE OF TARGET
O Terrestrial sensitive
environment
D Resources*
D Commercial agriculture
D Commercial silviculture
D Commercial livestock
production or grazing
D Terrestrial sensitive
environment
D Resources*
D Commercial agriculture
D Commercial silviculture
D Commercial livestock
production or grazing
O Terrestrial sensitive
environment
D Resources*
D Commercial agriculture
D Commercial silviculture
n Commercial livestock
production or crazing
D Terrestrial sensitive
environment
D Resources*
O Commercial agriculture
n Commercial silviculture
O Commercial livestock
production or grazing
HAZARDOUS SUBSTANCE




CONCENTRATION
(SPECIFY UNITS)




DETECTION
UMIT




REFERENCES




CO

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SI Data Summary                                       Site Name
                                 AIR INFORMATION
1.   Is air contamination present at the site?
    D Yes D No  D Uncertain but likely  D Uncertain but not likely
    D Additional sampling required
    Is analytical evidence available?    D Yes  D No             Reference(s)	

2.   Is air contamination attributable to the site?
    D Yes D No  D Additional sampling required

3.   Are populations,  sensitive  environments,  or wetlands  exposed  to airborne hazardous
    substances released from the site?
    D Yes D No  D Uncertain but likely  D Uncertain but not likely
    D Additional sampling required
    Is analytical evidence available?    D Yes  D No             Reference(s)	

4.   Evidence of blogas release from any of the following source types at the site:
    D Below-ground containers or tanks   D Landfill   D Buried surface impoundment
    Reference(s)      	

5.*  Paniculate migration potential factor value:	 (MRS Figure 6-2)

6.*  Paniculate mobility factor value:	 (MRS Figure 6-3)

7.   Distance from any  Incompletely contained source to nearest residence or regularly occupied
    area:  	miles      Reference(s)	

8.   Population within 4 miles of site sources.
DISTANCE FROM SITE SOURCES
0 (within site sources)
1/4 mile or less
>W4 to 1/2 mile
>1/2 to 1 mile
>1 to 2 miles
>2 to 3 miles
>3 to 4 miles
POPULATION







    Reference(s)
 9.* Resources within % mile of site sources (HRS Section 6.3.3):
    O Commercial agriculture
    D Commercial silviculture
    D Major or designated recreation area
    D None of the above

    Reference(s)      	
                                              19

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SI Data Summary                                      Site Name
10. Sensitive environments and wetlands within 4 miles of the site.
NAME/DESCRIPTION/LOCATION OF
SENSITIVE ENVIRONMENT OR
WETLAND







DISTANCE FROM
SITE (MILES)


•




TYPE OF SENSITIVE
ENVIRONMENT







WETLAND SIZE
(ACRES)







Reference(s)
11.    Using Table AIM, summarize air analytical results for all sampling Investigations. Include
       and identify background sample results.
                                             20

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                            TABLE AIR-1: SUMMARY OF ANALYTICAL RESULTS FOR AIR PATHWAY
SAMPLE ID
&DATE







SAMPLE
TYPE







DISTANCE FROM
SITE (MILES)



-



TARGET(S) WITHIN
DISTANCE CATEGORY
D Number of people
a Name of sens, environment

D Wetiand acreage
D Number of people
D Name of sens, environment

D Wetland acreaqe
D Number of people
D Name of sens, environment

D Wetland acreage
O Number of people
D Name of sens, environment

D Wetland acreage
O Number of people
D Name of sens, environment

D Wetiand acreage
D Number of people
a Name of sens, environment

D Wetiand acreage
O Number of people
O Name of sens, environment

D Wetiand acreage
HAZARDOUS
SUBSTANCE







CONCENTRATION
(SPECIFY UNITS)







DETECTION
LJMIT







REFERENCES







ro

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SI Data Summary                                Site Name
            ADDITIONAL INFORMATION AND COMMENTS
 Reference(s)
                                       • C.S. CWnUWEUT PRIHTIHC orPICI:1994-386-54 1 /034 17





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