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
-------
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.
-------
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
-------
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
-------
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
-------
Section 1:
Introduction
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
= 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
-------
Section 2:
Integrated Assessments
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
Section 3:
SI Approaches
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
Section 4:
Site Investigation Planning
Site-specific Work Plan
Health and Safety
Plan (HASP)
Site Sample Plan
Investigation-derived
Waste Plan (IDW)
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
SITE INVESTIGATION PLANNING
A Sample Plan Includes:
Field operationssequence for conducting field activities
Sample locations and rationalesample type, volume, number,
and sample map
Analytical requirements and sample handlingsample
equipment, container types, preservation techniques, and filtering
Sample deliverylaboratory 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 operationsdescribe hazards, list key safety personnel,
levels of protection by task, designate work areas, security,
environmental monitoring, training requirements, and weather-
related problems
Emergenciescommunication 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 entryconsent to entry by notifying owner in writing of
activities to be conducted (sample collection, photography)
Conditional entryconsent to entry with restrictions (limit area of
reconnaissance, employee interviews, records)
Entry with a warrantSI 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
managerSAM)
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
-------
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
-------
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
-------
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
-------
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
-------
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 containersdo
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
II 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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
APPENDIX A
Fact Sheets
-------
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 SACMInterim 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.
-------
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)
-------
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 assessmentstelephone
and file investigations, site visits or PA recons,
removal or SI sampling visitssuggest 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 sitesefficient
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
-------
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
-------
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 TeamsInterim 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
-------
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.
-------
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
-------
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.
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
15
-------
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
-------
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-
-------
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.
-------
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
-------
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
-------
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
-------
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
-------
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 pathwayAn
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 pathwayA 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
-------
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
-------
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
-------
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
-------
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.
-------
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
-------
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.
-------
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
-------
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
-------
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
-------
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.
-------
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.
-------
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
-------
APPENDIX B
Acronym List
and
Glossary
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
SITE NAME:
SOURCE SAMPLING STRATEGY
Sample ID
Sample Type
Rationale
Total Samples:
Special Sampling Considerations:
C«$« Stud/as
pageC-4
11/94
-------
BONUS SOURCE SAMPLING STRATEGY
SITE NAME:
Sample ID
Sample Type
Rationale
Total Samples:
Special Sampling Considerations:
11/94
Casa Studios
pageC-5
-------
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
-------
Sample to Test Suspected Contamination
Drainage
Ditch
Habitat for
Federally Designated
^ Endangered Species
Intake
1.200 els
-------
SAMPLING STRATEGY
SITE NAME:
Sample ID
Sample Type
Rationale
Total Samples:
Special Sampling Considerations:
Case Stud/as
pageC-8
11/94
-------
BONUS SAMPLING STRATEGY
SITE NAME:
Sample ID
Sample Type
Rationale
Total Samples:
Special Sampling Considerations:
11/94
Caso Studios
pageC-9
-------
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
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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
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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
-------
SI SAMPLING STRATEGY
Sample ID
Sample Type
Rationale
Total Samples:
Special Sampling Considerations:
Requested Analyses:
Caso Stud/as
page C-16
11/94
-------
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
-------
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.
-------
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)
-------
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)
-------
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)
-------
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)
-------
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)
-------
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.
-------
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)
-------
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
-------
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)
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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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