United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-420) VVF
EPA/530/UST-89/010
June 1989
Petroleum Tank Releases
Under Control
A Compendium Of Current
Practices For
State UST Inspectors
Printed on Recycled Paper
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Petroleum Tank Releases
Under Control
A Compendium of Current Practices
for State UST Inspectors
U.S. Environmental Protection Agency
Office of Underground Storage Tanks
June 1989
-------
ACKNOWLEDGEMENTS
The Environmental Protection Agency's (EPA's) Office of Under-
ground Storage Tanks (OUST) would like to express its gratitude
to the following individuals for their review and comments: Roger
Chu and Sharon Gerolamo of the Massachusetts Department of
Environmental Quality Engineering; Shawn Abbott and Gordon
Dean of the Florida Department of Environmental Regulations;
Terry Brazell and the California State Water Resources Control
Board (for the inspiration in the design of the cleanup scenarios
from their "Leaking Underground Fuel Tank Field Manual"); Jack
Hwang of EPA Region III and Steve Spurlin of Region IV; and
Helga Butler, Iris Goodman, Mike Kalinoski, Pam McClellan,
Dave O'Brien, Joseph Retzer, Peg Rogers, Tom Schruben, L.M.
Williams, and Tom Young of OUST.
Also, special thanks to Claudia Brand of IGF Inc. for working with
OUST to develop and to write this document and to the rest of the
project team for all of their efforts. The team included David
Brown, Allison Cogley, Vernon Dunning, William Finan, Linda
Hart, Jody Holtzman, Ed Meyer, Arch Richardson, Gardner Shaw,
and Jean Smith. Additional thanks to Paul Yaniga, Gary Gen-
teman, and Todd Schwendeman of Groundwater Technology Inc.
for their technical review and support and to Michael Boone of the
Washington Information Center for his production assistance.
Dana S. Tulis
Project Manager
June 1989
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TABLE OF CONTENTS
I. PURPOSE, CONTENT, AND ORGANIZATION
Purpose 1
Content 1
Organization . 3
II. INITIAL RESPONSE _____
Site information 6
Fire and safety hazards 6
Source and cause of release 10
Stopping free product flow 14
Vapor migration 16
Potentially affected community 16
Alternative drinking water supplies 17
Containment of free product 18
Security of site 19
Reporting requirements 19
Site Evaluation Checklist 21
III. LIMITED SITE INVESTIGATION
Scenario A. Minimal Soil Contamination
Locations of contamination 28
Soil screening 28
Minor soil contamination management 30
Reporting requirements 31
Site Evaluation Checklist 33
Scenario B. Extensive Soil Contamination
Potential sources, suspected areas of contamination,
and site conditions 36
Field preparation 36
Initial screening 36
Subsurface soil sampling 38
Evaluation of the extent of contamination 44
Source control and soil management 46
Reporting requirements 48
Site Evaluation Checklist 49
111
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TABLE OF CONTENTS
III. LIMITED SITE INVESTIGATION (CONTINUED)
Scenario C. Groundwater Contamination
Monitoring well locations
Monitoring well installation
Groundwater flow characteristics
Groundwater sampling
Assessment of groundwater contamination
Free product removal from ground water
Determination of groundwater uses
Alternative water supplies
Reporting requirements
Site Evaluation Checklist
52
52
55
56
61
61
65
65
66
67
APPENDICES
A. Vapor Control and Treatment Options
B. Transport of Contaminants
C. Tank Removal, Closure, and Repair Activities
71
79
83
WORKSHEETS
1. Site History and Tank Information
2. Preliminary Review of Impacts of Release
3. Evaluation of Anticipated Site Conditions
4. Preparation for Field Operations
REFERENCES
INDEX
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TABLE OF EXHIBITS
1. Common Occurences and Avenues of Hydrocarbon
Migration Following a Leak 8
2. Hydrocarbon Vapor Detection Meters 9
3. Information to Help Identify the Source of the Release 11
4. Sample Tank Inventory Record 12
5. Types of Facilities with Petroleum USTs 14
6. Identifying Possible Sources of Contamination 15
7. Selecting a Scenario 24
8. General Considerations Determining Magnitude
of Potential Impacts 25
9. Laboratory Analysis of Samples 39
10. Analytical Options 40
11. Well Drilling Methods 42
12. Split-Spoon Sampler 43
13. Typical Boring Log 45
14. Soil Management Options 47
15. Typical Monitoring Well 53
16. Method to Determine Water Table Elevation and
Product Thickness 58
17. Purging Equipment 59
18. Free Product Recovery 62
19. Trenches and Recovery Wells 63
20. Barrier Installations 64
A-l Passive Vapor Control System 72
A-2 Active Vapor Control Systems 74
A-3 General Considerations for Active Vapor Control Systems 75
A-4 Catalytic Converter 77
B-l Typical Seepage Patterns 80
B-2 Hydraulic Conductivity of Selected Rocks 82
Vll
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I. PURPOSE, CONTENT, AND ORGANIZATION
Purpose
Tank Releases Under Control is intended to help States
train inspectors of underground storage tanks (USTs); it also
provides new and experienced inspectors with ways to evaluate
options for controlling releases from leaking USTs. The document
is flexible enough to be used by States regardless of their specific
requirements, conditions, and practices.
.The document is a compendium of general knowledge based on
standard engineering practices; and, as such, it covers a wide
range of activities. Remediating dissolved contamination in
ground water is not addressed, however, because of the
complexity of this topic and because of the ongoing work in this
area.
As stated above, this document is a baseline of general knowledge.
As developments and improvements evolve in the field, and as the
Office of Underground Storage Tanks (OUST) continues to focus on
specific project areas, this document will be updated.
Content
Chapter II contains descriptions of the first actions to take at a
site with an UST that is leaking petroleum. In this document, we
employ the commonly used phrase "initial response" to describe
these activities. During this stage of the cleanup, State UST
inspectors may need to gather information about the site to help
determine the cause of the leak or release. In addition, UST
inspectors might oversee the activities necessary to stop the flow of
free product, to ensure that fire and safety hazards have been
mitigated, and to determine whether other response actions (such
as vapor migration control) are needed. Inspectors may also
oversee the responsible party's investigation to determine whether
an alternative drinking water supply is needed.
Chapter III provides a list of the actions to take once the initial
response is completed. We call this a "limited site investigation."
It begins with selection of a scenario based on review of available
information and anticipated contaminant migration. The three
scenarios are: Scenario A, Minimal Soil Contamination; Scenario B,
Extensive Soil Contamination; and, Scenario C, Groundwater Con-
tamination. Depending on site-specific conditions, the activities in
one or more of the scenarios may be applicable. For example, if
groundwater contamination is discovered at the outset, Scenarios A
and B serve as the basis for investigating the release before con-
tinuing on to Scenario C.
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Organization
Because it is a training tool, Petrole/wr"
Reeases Under
Control is designed primarily for office use; however, certain pages
(e.g., checklists and worksheets) can be photocopied and used in
the field during inspections.
A step-by-step approach is used to present information. Not
every step is necessary for every situation and the sequence of
steps may vary depending on site conditions. We encourage
State inspectors to use their discretion in determining which
steps to take at each site.
In addition, we've used symbols (small icons) to help readers locate
information quickly, to highlight added details, and to identify
specific field and evaluation tools. The following icons identify
Chapters II and III respectively and are placed at the bottom of
the corresponding chapter page.
Fire Truck Initial Response; Chapter II
Detective Limited Site Investigation; Chapter III
The remaining icons highlight added detail or identify specific field
and evaluation tools. These symbols and their meanings are:
Stop Signs
=/ Checklists
Detailed information for you to know when
implementing a step.
Reminders and progress tracking sheets you can
use for supplementing other documentation.
Worksheets Tools to help you evaluate individual release
incidents.
In addition to this document, OUST has developed other source
materials for corrective action and tank closure. Ordering infor-
mation for these materials can be found in the References.
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II. INITIAL RESPONSE
The descriptions of initial response steps included in this chapter
will help inspectors evaluate the selection and implementation of
measures, taken by the owners/operators or contractors, to clean
up leaking petroleum underground storage tanks (USTs). These
steps address the suggested approaches on how to:
• Gather basic information about the site;
• Identify, monitor, and mitigate fire and safety hazards;
• Identify the source and cause of the release;
• Stop the flow of free product;
• Initiate vapor control, collection, and treatment by using either
passive or active control systems;
• Determine if public and private water supplies have been con-
taminated;
• Provide alternative drinking water supplies, if necessary;
• Initiate the collection of free product in basements/sewers and
surface waters;
• Secure the site in order to discourage unauthorized entrance or
vandalism; and
• Report all required information on site activities to the imple-
menting agency.
The need for some, or all, of these steps is contingent
upon the site-specific situation.
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Site Information
Step 1 Has information on site history, tank usage, and impacts of the
release been compiled by an inspector or contractor?
In order for inspectors to begin evaluating a release situation, it is
important to gather basic information about the site. Inspectors
should try to answer the following types of questions concerning
initial response to a release: Where is the release located? Who
reported it? What appears to have taken place at the site? (Work-
sheets 1 and 2, in the Worksheet section, have been provided to
assist with the gathering of this information.)
This initial information provides the foundation of an inspector's
understanding and assumptions about a site. Therefore, it will be
important to check these early assumptions (e.g., regarding poten-
tial sources and direction of groundwater flow) as additional infor-
mation is gathered throughout the project.
Fire and Safety Hazards
Step 2 Have fire and safety hazards been identified, monitored and
mitigated?
If vapors or liquids are detected or suspected in a confined area, a
quick assessment is necessary to determine the presence of fire
and explosion hazards. This type of assessment is based on vola-
tility of the spilled substances, approximate amount released, and
amount of time elapsed since the release. If a fire and safety
hazard exists, it is important to ensure that proper health and
safety measures have been performed. Step 5 and Appendix A
provide more details on vapor control.
During initial response, inspectors may need to verify that the
following steps have been taken (some of these measures may need
to be repeated or maintained over a period of time, depending on
specific site conditions).
2.1 Has the local fire department and/or State been
alerted?
2.2 Has an operator trained in the use of a combustible
gas indicator and an oxygen indicator (e.g., from the
State and/or local fire department) determined if
vapors are present at the site outdoors and/or in-
doors? And if present, at what concentrations?
ilii, i ,.f •m
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2.3 Have all persons been evacuated from the areas
where unsafe hydrocarbon levels have been found or
suspected (except for properly trained and equipped
persons)?
2.4 If flammable vapors or liquids have been detected at
levels dangerous to human health or property (e.g.,
near the lower explosivity limit), have the following
steps been performed?
• Notification of appropriate State and local authorities
and the facility owner/operator;
• Enforcement of security measures such as posting of
notices to warn the public of potential danger;
• Elimination of ignition sources that may be present in
vapor contaminated spaces (e.g., vapor-fired heaters,
light switches, non-explosion-proof motors, and electri-
cal items); and
• Ventilation of confined areas by opening windows and
doors and by using an explosion-proof exhaust fan to
dilute concentrations (this may need to be done prior to
entering the area).
The following additional factors are important to consider when evaluating
safety hazards:
• All gasoline vapors are heavier than air, therefore it is necessary to monitor
air near the ground or foundation as well as in the breathing zone.
• Elevator shafts, telephone lines, electrical cables, subways, and sewers are
common migration routes and collection points. (Exhibit 1 shows common
migration pathways of a tank release.)
• In explosive situations, ignition sources may not always be obvious.
Precautionary measures may need to be taken to prevent sparks and static,
e.g., when starting cars or using metal objects.
• The selection and use of detection meters for hydrocarbon vapors should be
based on their applicability to site-specific conditions. (See Exhibit 2 for
descriptions of hydrocarbon vapor detection meters.) For example,
explosimeters should be calibrated for the volatile compound of concern and
are generally most effective when used with an oxygen indicator for
determining high concentrations of contaminants and explosive conditions in
confined spaces. A photoionization detector, on the other hand, is more
suitable for identifying lower concentrations that are a concern because of the
risk of long-term exposures.
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00
EXHIBIT 1
Common Occurrences and Avenues of
Hydrocarbon Migration Following a Leak
VAPORS LOST TO
ATMOSHPERE
UNDERGROUND
UTILITIES
STORAGE
TANK
SOIL CONTAMINATED BY
ADSORBED RESIDUAL HYDROCARBONS
BOUND TO SOIL PARTICLES
VAPOR MIGRATION ALONG
SEWER LINE
ACCUMULATED MOBILE
HYDROCARBONS
WATER TABLE
HYDROCARBON/WATER
INTERFACE
DISSOLVED HYDROCARBONS IN WATER
MIGRATING DOWN WATER TABLE GRADIENT
Source: Groundwater Technology Inc.
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Hydrocarbon Vapor Detection Meters
Air
Monitoring
Meters (1)
Combustible
Gas Indicator
(CGI or
Explosivity
Meter) (3)
Oxygen
Indicator (3)
Flame
lonization
Detector
(FID) (4)
Photoionization
Detector (PID)
(4)
Infrared
Colormetric
Tube
Portable Gaa
Chromatograph
(can be equipped
with PID or FID)
Danger of Volatilization
Examples of Ranges Vapors in Fires and of Chemicals
of Detection (2) Soil Explosions to Air
0-100% LEL XX
(Response is
relative to the
calibration gas)
Indicates X
Oxygen Content
0-30% (variable)
0.6-10,000 ppm X X
approximate
(Response is
relative to the
calibration gas)
0-2,000 ppm X X
approximate
(Response is
relative to the
calibration gas)
Sppm-100* X X
Variable (e.g., XX X
0.001-10,000 ppm,
0.1-10% by volume)
0.6-10,000 ppm (FID) X X
0.01-1,000 ppm (PID)
Vapors in Vapors in
Vapors in Sewer Ambient Approximate
Buildings Pipes Air Cost Limitations
X X $600-16,000 • Accuracy of reading depends on difference between
calibration and ambient sampling temperatures, humidity,
and atmospheric pressure
• Calibration to methane and pentane may alter accuracy
of readings of other substances
• Certain chemicals (e.g., leaded gasoline) may damage the
filament on 'hot wire" models, reducing the sensitivity
• Response is qualitative
X X (Often • Does not detect fuel hydrocarbons
built into • Accuracy affected by altitude and temperature. Instrument
CGI) must be calibrated under condition of use
XXX $6,000-$7,600 • Does not detect inorganic gases or vapors
• Requires identification of chemical before it can report its
concentration
• Can be affected by humidity and moisture
• • Qualitative data only
XXX $4,000-16,000 • Does not detect methane
• Presence of high concentrations of methane or humidity may
alter reading drastically
• Interference from power lines, water vapor, transformers,
high voltage equipment, and radio wave transmissions may
alter readings
• Qualitative data only
XXX $1,750-$9,000 • False positives may occur due to interference of other gases.
XXX $2-6Vtube • Accuracy of readings subject to human error
• Responses of different models of tubes may vary
• Responses affected by humidity, temperature, other
contaminants present, and age of tube
XXX $7,000-160,000 • Accuracy of results affected by ambient conditions when using
some models
• Reading is not direct
• Portable units tend to be less accurate than lab-based GC '
• Lower detection limits can be obtained depending on
manufacturer and detector
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Source and Cause of Release
Step 3 Have the source and cause of the release been satisfactorily
identified?
A recent review of case studies from several States indicates that
misidentification of the source of the release is a common problem
leading to delays and costly cleanups. To avoid this error, an
inspector should be aware that the nearest facility, tank, or line is
not always the source. Therefore, it is important to review avail-
able information about the site and surrounding areas. The
inspector may also want to visit the site as soon as possible to
confirm initial assumptions.
3.1 Has information from the suspected facility, local
and/or State officials, and from surrounding facili-
ties been reviewed by the inspector or contractor
(see Exhibit 3)?
Although a review of inventory records can be time-
consuming, a quick review may be especially helpful in
discovering large leaks or in determining which of several
tanks is the most likely one to be leaking. See Exhibit 4 for
an example of a tank inventory record. When reviewing
inventory records and interpreting discrepancies, the
following guidelines are helpful:
• If a facility owner/operator's daily stock readings, sales
records, and/or delivery receipts are incomplete or
missing, other investigative steps should be pursued.
• Daily records should be reconciled on a monthly basis.
Looking at less than 30 days of information at a time
can be highly misleading.
• Discrepancies in inventory data can be caused by sev-
eral factors other than a leak. The most important of
these are: 1) errors in delivery receipts, 2) temperature
changes which cause the fuel to expand when heated or
contract when cooled, creating the appearance of a leak,
3) errors in pump meter calibration, 4) product loss due
to evaporation, and 5) theft. Each of these errors is
more significant for larger tanks and larger sales vol-
umes (throughput).
• Generally, a leak is suspected when monthly discrepan-
cies exceed 1% of throughput plus 130 gallons. If a
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large discrepancy is found, the reconciliation should be
reviewed for math errors and the calibration of pump
meters should be checked. If these items are not found
to be the source of the error, additional investigation of
the tank with the discrepancy may be required.
EXHIBITS
Information to Help Identify the Source of the Release
The following items are examples of information that may be useful:
• Map or sketch of the area identifying operating and abandoned facilities
with petroleum product storage
• Locations of active/inactive tanks in the area
• Records of past leaks on site
• Precision testing results
• Inventory and repair records
• Records of any water pump-outs from the tank(s)
• Observations by fire department and other local officials
• Information on past ownership and site uses (refer to old maps and
atlases)
• Equipment installation and maintenance data
• Data from leak detection systems installed on suspicious tanks
• Well logs from on-site or nearby monitoring wells or water supply wells
• Boring logs from engineering studies
• Interviews with employees and neighbors
3.2 Has a site inspection been conducted to observe site
conditions?
A site inspection may reveal information regarding:
• Evidence of leaks, spills or overfills (e.g., stained soils
and irregular vegetation patterns);
• Tank locations upgradient and upstream of sewer or
conduit flow;
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EXHIBIT 4
Sample Tank Inventory Record
*'/
Tank ID ^/Capacity
Product Unleaded.
Month/Yr IO
Operator
Cotunm 1
0*y
1
2
3
4
S
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
2
Opening
Dipstick
Inventory
(galore)
3001
37SV
3/63
763/
7/V3
&636
&Z.67
791?
*?V27
V6V7
^936
3977
3V26
7
Closing
Dlpsdok
Inventory
(Inches)
33 '/2
2S'/z
2V
75
73
67 Vi
6/
77 Vz
70'/z
V7
V/
3^
3V '/2
6>fr
(p/
76 Vz
77
Vg'/z.
W
vo
3V '/i
80
7V
70
6fo'/z
6/'/z
7*/
72
^7V2
^2Vz
39
8
Closing
Dipstick
Inventory
(galons)'
2^92-
/99Y
Iftoto
69S/
&7V6
toO 27
7376
VSC7
V276
3903
3268
Z97V
Z5V2
f879
7376
*/9/^
V3Z9
V0&V
37»V
3/fi>3
Z793
7/V3
6>6>36>
6Z67
79 2g
7V2?
V6V7
W36
3977
3V26
30*58
9
QoneFrom
Tank
(column 6)
minus
(column 8)
7/V
H9S
V28
773
V37
72/
&V9
77/
729
37J
637
3/V
V/Z
^76
7£>3
3V
VV
2-73
307
8
5/
/07
Charts converting dipstick readings (in inches) to gallons are specific for each type and size of tank. Consult
the manufacturer for the appropriate chart if it is not already provided.
Source: ICFInc.
12
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• Evidence of other possible sources of contamination at
surrounding facilities (see Exhibits 5 and 6);
• Recent excavation or signs that a tank or piping system
has been repaired;
• Water in the underground tank; and
• Evidence of free product or dissolved constituents in
samples from drinking water wells, observation wells (if
available), collection sumps, or surface water.
Vapors and liquids from petroleum releases may not always be detectable in
subsurface structures or in wells depending on the site-specific geology,
hydrogeology, and recent weather conditions. For example, a gasoline spill in
low permeability soil, such as clay, where depth to ground water exceeds 10 feet,
may not appear for over a month. Rain can also sometimes mask the presence of
contamination. As a result, it may be prudent to resample suspected locations
on more than one occasion, i.e., after the aquifer system is expected to have
returned to equilibrium. In general, the more permeable the soil, the more
quickly it will return to relative equilibrium and yield representative data
following precipitation.
3.3 If review of available information has failed to con-
firm the source, has a tightness test been performed
on tanks and underground lines?
Due to the numerous types of tank tests available, it is
necessary to evaluate a proposed test method based on its
performance claim. It should be noted, however, that the
accuracy of tank tests is variable and may be influenced by
factors such as temperature, the elevation of the water
table, tank shell deformation, product evaporation, tank
and piping layout, wind vibration and noise, and operator
error.
Product levels, for example, can fluctuate in a tank due to
temperature disturbances that occur from opening the fill
hole, the addition of product, and tank deformation. There-
fore, it is important that there is an adequate waiting
period to allow stabilization prior to starting a tank test.
As a result of the variability, tank test results often cannot
be considered to be conclusive and are best used in conjunc-
tion with the other available evidence such as historical
records and available field data.
13
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EXHIBITS
Types of Facilities with Petroleum USTs
The following facilities often store petroleum products on site:
• Service stations (existing, abandoned, or converted)
• Automobile dealerships and auto repair garages
• Municipal garages
• Fleet operators such as taxicab companies, bakeries, dairies, contractors,
bus companies
• Industries, including refineries, terminals, and bulk plants
• Commercial operations (e.g., convenience stores, cleaning
establishments), airports, schools, hospitals
• Abandoned oil and gas well sites
• Subsurface disposal systems (including drywells and deep injection wells)
• Machine shops
• Salvage yards
Stopping Free Product Flow
Step 4 Has the flow of free product into the environment been stopped?
Stopping the flow of product often requires the following steps:
• Shutting off product dispensing equipment (pumps and valves)
during repair or replacement;
• Removing product from the tank and the lines;
• Monitoring and recording the amount and flow of product
during suspension of use; and
• Shutting off power sources as necessary.
•BKBHffi H
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EXHWT6
Identifying Possible Sources of Contamination
1
1 / \
•^T*» Vacant Lot /V^ }
A f *<* (
( (possible )
Airport Potential Source » spBI location) /
(less Ikely potential '~"A. -^^
source due to location)
1 Property Line
. 1
Gas Station O £3*5-.
01 • (Potent'al source) Q
Tank " '" |
m- m- m- h — , ' >
Pump Islands 1 - - - ^r
m- m- m- — •• jf
/
Assu
Direct
Grounc
Fh
Potential Sources
Salvage T^^%. O ^
Yard ^^E/Q ^f?
Automobiles ^^^ ^u ^nma
S ._.
' GaS Station O Concrete Pad
(potential source) Q Cover lor USTs
mod '
Wrtor : W- ii- » r - - '
3W Pump island
(possible conduit for product transport)
MAIN STREET
Residence
(no vapors In
basement)
(shallow)
Drinking water
wells. Slight
odor detected In
shallow wed.
Residence
(vapors in
basement)
Heating
Oil
Tank
entlal source)
Residence
(no vapors in
basement)
Contaminated Site
Jackson Creek
(Potential lor surface water contamination from surface
run-off a discharge of contaminated ground water)
Shallow Well
(no odors detectable)
Source: ICFInc.
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Vapor Migration
Step 5 Has a determination been made as to the need for vapor
migration control, collection, and treatment?
Hydrocarbon vapors and released petroleum products often enter
confined structures such as buildings, sewers, telephone vaults,
other utility lines, and tunnels. If vapors and/or liquids have been
detected, a recovery system may be needed near the point of entry
to intercept the product or vapors before they enter the confined
structure.
Either passive or active vapor control systems may be selected
depending on site-specific conditions (see Appendix A). Vapor
control can extend over a substantial period of time, however, it is
often necessary to determine the need for it, and begin the process
during the initial response stage.
Structures and human health must be adequately protected during implemen-
tation of vapor control. Precautionary measures may entail isolating the area of
concern, ventilating with equipment having explosion-proof motors and gears,
and eliminating and/or controlling ignition sources.
Potentially Affected Community
Step 6 Has the potentially affected community (e.g., nearby well owners)
been identified?
Before deciding if provision of alternative drinking water supplies
is necessary, inspectors may need to complete or review an assess-
ment of groundwater use.
6.1 Has information on the number, location and depth
of public and private wells, and the number of
people connected to these supplies been evaluated?
This step may involve the following:
• Reviewing available zoning or property plans for the
nearby area to determine the location of residences,
businesses, and municipal wells;
16
***
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• Reviewing local Public Works and/or Water Department
records to identify other potential well users;
• Conducting a field survey in the vicinity of the site (i.e.,
drive around neighborhood) to identify any other poten-
tial users;
• Reviewing available well logs to determine the depth
and rate of pumping for the identified wells;
• Reviewing Health Department records for complaints
registered for petroleum odor or taste in the area's
water; and
• Surveying possible owners of wells and sampling their
wells for evidence of contamination.
6.2 Based on the extent of contamination, has a determi-
nation been made as to whether or not water sup-
plies need to be replaced or treated?
The following measures may need to be conducted in order
to make this determination:
• Collecting water samples from the well or tap for analy-
sis (i.e., testing for volatile organic compounds and/or
petroleum hydrocarbons depending on the type of prod-
uct — see Chapter III, Scenario B, Step 4); and
• Evaluating the analytical data using available State
and Federal drinking water criteria.
Alternative Drinking Water Supplies
Step 7 Have alternative drinking water supplies been provided?
Depending on the extent of contamination and the feasibility of
aquifer restoration, a temporary and/or emergency water supply
may be needed until a permanent alternative is found or until the
existing supply is restored.
7.1 Has a plan been initiated to determine how to inform
residents of potential problems with their water
supplies?
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7.2 Have measures been taken to provide a temporary
alternative water supply (if applicable)?
This may include using one of the following techniques:
• Providing bottled or bulk water;
• Providing point-of-entry home treatment units (e.g.,
carbon adsorption systems); and
• Installing rainwater collection systems.
In general, if aquifer restoration can be accomplished within a few years,
provision of temporary point-of-entry home treatment units may be practicable.
As an initial response, point-of-entry systems or bottled sources will probably be
required for a limited period of time before implementation of a permanent water
supply. If aquifer restoration is not feasible in a reasonable timeframe, then a
permanent alternative water supply should be developed as a long-term measure
during remediation of ground water (see Chapter HI, Scenario C, Step 8).
Containment of Free Product
Step 8 Has the containment of free product been initiated?
During the initial response to a release, free product may be
encountered in sumps, tank pits, sewers, basements, elevator
shafts, subway tunnels, telephone manholes, or seeping to surface
waters. In such cases, containment of free product can be initiated
as an interim measure until the limited site investigation can be
completed.
Where seepage discharge to small streams occurs, the use of
berms, dikes, booms, and/or sorbent materials may be used to
contain the product. If free product has contaminated a river or
large stream, the spill should be monitored to predict if and where
it will reach the shore. Once this occurs, the floating spill can be
contained with a boom. Encircling booms are useful when floating
free product has contaminated a slow-moving body of water (e.g.,
lake, lagoon, pond, or large river). Recovery of free product is most
often achieved by one of several pumping methods. See Chapter
in, Scenario C, Step 6 for a discussion of longer-term free product
removal from ground water.
-------
Security of Site
Step 9 Has the site been sufficiently secured?
Sites often need to be secured to prevent unauthorized entrance
and vandalism, particularly on abandoned sites and those with
open excavations. Security measures may include the following:
tightly closed and properly stored drums of recovered product and/
or absorbent materials; plastic covers over any excavated soils;
gates, buildings, and equipment locked; fencing or brightly colored
tape around excavations and at entrances; and notices posted as
warnings for the public.
Reporting Requirements
Step 10 Have all site activities been reported in accordance with State
and Federal requirements?
Inspectors should ensure that owners/operators comply with State
and Federal reporting requirements concerning initial response to
petroleum UST releases. The requirements usually include provi-
sions for reporting all suspected and confirmed releases, completed
and planned initial response activities, and any resulting informa-
tion and data.
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SITE EVALUATION CHECKLIST
INITIAL RESPONSE
SITE NAME/ID*:
SITE COORDINATOR:
Step 1: Has information on site history, tank usage, and impacts of
the release been compiled by an inspector or contractor?
(Use Worksheets 1 and 2.)
Step 2: Have fire and safety hazards been identified, monitored,
and mitigated?
Step 3: Have the source and cause of the release been satisfactorily
identified?
Step 4: Has the flow of free product into the environment been
stopped?
Step 5: Has a determination been made as to the need for vapor
migration control, collection, and treatment?
Step 6: Has the potentially affected community (e.g., nearby well
owners) been identified?
Step 7: Have alternative drinking water supplies been provided?
Step 8: Has the containment of free product been initiated?
Step 9: Has the site been sufficiently secured?
Step 10: Have all site activities been reported in accordance with
State and Federal requirements?
Date Completed/
By Whom
Note: Not every task may be applicable in all situations, and the sequence of
steps will vary somewhat from site to site.
21
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III. LIMITED SITE INVESTIGATION
This chapter presents three scenarios that correspond to the
severity of contamination which may be found at various sites.
Scenarios may also evolve sequentially at one site (that is, results
of one scenario may lead the investigation into the next scenario).
The three scenarios discussed in this chapter are:
• Scenario A: Minimal Soil Contamination
• Scenario B: Extensive Soil Contamination
• Scenario C: Groundwater Contamination
The decision as to what constitutes minimal soil contamination as
compared to extensive soil contamination rests with the imple-
menting agency. To select the appropriate scenario, it is impor-
tant to review the available information from the Worksheets, the
results of the initial response tasks, field observations, site history,
hydrogeology, soil characteristics, and other site-specific data. See
Exhibit 7 for descriptions of the type of site that may fall under
each scenario. For determining the magnitude of potential
impacts to soil and/or ground water, see Exhibit 8 which illustrates
the general interrelationship between soil permeability and
adsorptive capacity. (Additional information on one method to
determine transport of contaminants is presented in Appendix B.)
The key to the limited site investigation process involves ongoing
questioning and reevaluation of assumptions about site conditions.
Typical questions to ask during the process include:
• Have all of the potential sources of contamination been
identified?
• What additional information could be obtained and reviewed?
• Based on the new information received, are the owner/opera-
tor's or contractor's assumptions true?
23 Y_l
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IIBIT7
Selecting a Scenario
Scenario A — Minimal Soil Contamination
Scenario B — Extensive Soil Contamination
Scenario C — Groundwater Contamination
Leaks or spills suspected to have occurred
recently
Only small quantity release suspected
Presence of low permeable soils is expected to
have minimized migration
Field screening indicates low concentrations
present in soils
Visual observations of discoloration at surface
or during excavation. Failure of tank or piping
tightness test
Failure of tank or piping tightness test
Discrepancy in inventory
Leak suspected due to age of tank or evidence of
a previous underground storage tank leak
Field screening indicates positive reading above
designated background levels*. Groundwater
contamination observed during excavation of
leaking tank or piping
Groundwater contamination observed during
excavation of leaking tank or piping
Observations and records indicate significant
loss of product
Odors detected in drinking water near source
High permeability of natural soils and/or high
water table*
* NOTE: High readings in soils with low permeabilities (e.g., >100-1,000 ppm in clays) may indicate only localized contamination, whereas lower readings in
high permeability soils (e.g., 10-50 ppm in sand and gravel) could indicate that contamination has rapidly migrated to greater depths.
Source: ICF Inc.
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EXHIBITS
General Considerations Determining
Magnitude of Potential Impacts
General Curve for Adsorptive Capacity versus Permeability
HIGH
RELATIVE
ADSORPTIVE
CAPACITY
LOW
HIGH
(GRAVEL)
PERMEABILITY
LOW
(CLAY)
General Curve for Impact to Ground Water
HIGH
IMPACT TO
GROUND
WATER
LOW
LOW
(GRAVEL)
HIGH
(CLAY)
RELATIVE ADSORPTIVE CAPACITY
Source: Groundwater Technology Inc.
25
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SCENARIO A. MINIMAL SOIL CONTAMINATION
Sites addressed under this scenario are locations where evidence
gathered during initial response and a review of the site history
indicate that minimal contamination to the soil has occurred. For
example, minimal soil contamination may be expected in those
cases where a release is recent and consists of a small quantity of
product. In this scenario, inspectors may need to ensure that the
following activities are conducted:
• Identification of locations of minimal soil contamination;
• Soil screening for hydrocarbon vapors to confirm the presence
of minimal contamination or the need to continue to
Scenario B;
• Management of contaminated soil (if necessary); and
• Submission by owner/operator of all information relating to the
cause of the release and the status of the site to the State.
The need for some, or all of these steps is contingent upon
the site-specific situation.
27
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Locations of Contamination
Step 1 Have all of the locations of minimal soil contamination been
identified?
The identification of these areas may be based on visual observa-
tions of discolored or saturated soils, detectable odors, and/or
knowledge of historical activities (e.g., soils near a gas pump).
Such evidence may be gathered during the initial response phase
of a cleanup, and during the excavation and removal of a tank and
lines. Tanks are often removed as a provision of a real estate
transaction and are frequently the reason minimal contamination
is discovered. (For more information on tank removal, closure or
repair activities, see Appendix C.)
Soil Screening
Step 2 Have the soils been screened for hydrocarbons to confirm the
presence of minimal contamination or the need to continue to
Scenario B?
Field screening for hydrocarbons in soils can provide valuable
information to help verify that only minimal contamination is
present. Soil screening is typically accomplished by conducting a
soil gas survey or by collecting shallow soil samples and testing
them in the field. Soil gas surveys involve making a small
diameter hole and either inserting a detection meter probe into the
hole or extracting a vapor sample for screening. Shallow soil
samples can be collected using a trowel, bucket auger, or shovel.
The following four factors can affect the accuracy of soil screening:
• Selection and operation of the detection meter;
• Consistency of screening procedures;
• Number and location of soil samples; and
• Interpretation of the results.
Details on these four factors are discussed in Substeps 2.1 to 2.4.
28
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2.1 Has the appropriate type of instrument been
selected based on anticipated concentrations?
See Exhibit 2 on page 9 for a list of types of meters. To
some extent, meter selection will be dictated by State
preferences, sensitivity requirements, and general equip-
ment availability.
The quality of the data is extremely variable depending on equipment
maintenance, calibration, its operator, and climatic conditions. To obtain good
quality data, the equipment manufacturer's instructions for maintenance and
calibration should be carefully followed.
2.2 Have sampling procedures been consistent at the
site?
The soil gas survey method is most frequently used for
larger areas where more significant contamination is sus-
pected. Hence, more detailed discussion of this method is
presented in Scenario B, Substep 3.1.
Shallow soil samples can be collected in a number of ways.
More important than the type of equipment used, however,
is the consistency of the procedures across the site. (This
ensures that the data can be compared.)
One example of a soil sampling method is as follows:
Soil is placed in a precleaned, airtight, glass jar and filled to approximately two-
thirds of capacity. Screening procedures are as follows:
• Close the jar tightly;
• Place it in an area of controlled temperature;
• Shake the jar vigorously after it reaches room temperature (approximately
15 minutes); and
• Place the indicator probe in the jar to measure the concentration of organic
vapors.
Other methods for screening samples include:
• Puncturing a hole in the jar lid to extract a known volume of sample with a
needle (then injecting the needle into the detection meter); or
• Immediately after sampling, covering the jar with foil and then capping it.
When it is time to screen the sample, the cap is removed and the probe is
inserted through the foil.
Precautions need to be taken to prevent the volatilization of contaminants from
the sample. In those cases where soil samples are allowed to aerate or are
placed in warm locations, screening results will not be an accurate reflection of
the actual level of contamination.
29
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2.3 Have the number and the locations of soil samples
been sufficient for the specific site conditions?
In general, samples are collected directly from the identified
contaminated area and from one or more background
locations around the perimeter of the release. By comparing
the results from each of the locations, an evaluation can be
made as to the relative amount of contamination. (State
agencies may have specific policies on this matter.)
Samples obtained from tank removal excavations are
usually collected where soils are discolored and where the
backfill and the native soil meet. Additionally, soil may be
sampled at the following locations within the excavation
pit: the bottom center where stick testing may have worn
through the tank, near the soil surface, and at the area
previously adjacent to the fill end of the tank.
2.4 Have hydrocarbon vapor test results been correctly
interpreted?
If test results show minimal contamination — based on
State guidelines and/or the presence of such small amounts
so as not to be a threat to human health and the environ-
ment — soils may need to be managed as described in
Step 3. Following soil management, a repeat of soil screen-
ing may need to be conducted to confirm that cleanup was
adequate.
If test results show significant soil contamination, as deter-
mined by the implementing agency, the investigation
should proceed to Scenario B.
Minor Soil Contamination Management
Step 3 Has minor soil contamination been managed?
If soil contamination is minor and the release will be controlled
upon completion of this scenario, contaminated soils may be left in
place or excavated for disposal or treatment on or off site. Follow-
ing removal or treatment, another soil screening test is usually
conducted to verify that minor contamination is no longer present
on site.
Managing soils in this scenario generally involves small scale
removal and treatment operations as described in Scenario B, Step
6 and in Exhibit 14 on page 47. Those methods most applicable to
30
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this scenario include: leaving small quantities of soils with low con-
centrations on site to degrade naturally; excavating and removing
small quantities of soils with relatively high concentrations for off-
site disposal (e.g., at landfills or asphalt batching facilities); and
using enhanced volatilization and soil venting for large quantities
of soils with lower concentrations of total volatiles.
Reporting Requirements
Step 4 Have owners/operators submitted all information relating to the
cause of the release and the status of the site to the State?
Owners/operators should comply with existing State and Federal
reporting requirements concerning petroleum UST releases. At
this stage of the process, owners/operators will likely be required
to report all information on the cause of release, the estimated
quantity of product released, the surrounding population, subsur-
face soil conditions, and locations of drinking water wells.
31
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SITE EVALUATION CHECKLIST
SCENARIO A. MINIMAL SOIL CONTAMINATION
SITE NAME/ID#:
SITE COORDINATOR:
Step 1: Have all of the locations of minimal soil contamination been
identified?
Step 2: Have the soils been screened for hydrocarbons to confirm the
presence of minor contamination or the need to continue to
Scenario B?
Step 3: Has minor soil contamination been managed?
Step 4: Have owners/operators submitted all information relating to
the cause of the release and the status of the site to the State?
Date Completed/
By Whom
Note: Not every task may be applicable in all situations, and the sequence
of steps will vary somewhat from site to site.
33
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SCENARIO B. EXTENSIVE SOIL CONTAMINATION
An example of a Scenario B site is a location where a significant
quantity of product was released relatively recently in permeable
soils, and the contaminants have migrated through the subsurface
with the percolation of rainwater. Alternatively, a release of
product over time in less permeable soils (i.e., silts and clays) may
also result in extensive soil contamination, since contaminants
tend to adsorb to the material and migration to ground water may
be limited. When information from the initial response and/or
Scenario A activities reveals evidence of extensive contamination
to soils, the inspector may consider the following:
• Identification of potential release sources, suspected areas of
contamination, and site conditions;
• Preparation for field operations;
• Preliminary screening to confirm the presence of vapors and to
identify areas of highest contaminant concentrations;
• Collection of subsurface soil samples to determine the vertical
extent of contamination;
• Evaluation of soil data to determine the extent of soil
contamination and the need to continue to Scenario C;
• Source control (if applicable) and soil management; and
• Submission of information concerning the cause of the release
and the status of the site to the State.
The need for some, or all, of these steps is contingent upon
the site-specific situation.
35
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Potential Sources, Suspected Areas of Contamination, and Site Conditions
Step 1 Prior to initiating field work, have all potential sources,
suspected areas of contamination, and site conditions been
identified?
In order to evaluate a field program, inspectors need to understand
a site's hydrogeologic conditions to help determine release sources
and suspected areas of contamination. Worksheet 3 provides an
outline of the type of information that could be reviewed in the
beginning of this scenario. This is also a good time to review
information gathered during Initial Response activities (see Chap-
ter II, Step 3) and information gathered during the activities
undertaken in Scenario A.
Field Preparation
Step 2 Have adequate field preparation measures been taken by
contractors and oversight personnel?
Failure to adequately anticipate site conditions and prepare for
field operations may result in costly delays or errors. For example,
sampling locations should be sited to avoid underground utilities.
See Worksheet 4 for information on field preparation. Delays can
often be prevented if the involved parties are aware of the impor-
tance of careful planning before initiating field work.
It is important that all of the involved parties maintain complete field notes.
(See the Site Inspection and Telephone Logs accompanying Worksheet 1.) These
notes provide the foundation for numerous project management activities such
as budget tracking and report writing and can sometimes provide important
materials in legal disputes.
Initial Screening
Step 3 Has initial screening been conducted to confirm the presence of
vapors in soils and to identify areas of highest contaminant
concentrations?
Initial soil screening methods may be used to further narrow the
set of potential sources of a release and to help locate subsequent
soil sampling points. The basic screening methods are the same as
those described in Scenario A, Step 2 on page 28, and include soil
gas surveys and shallow soil sampling.
36
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Soil gas surveys measure the hydrocarbon vapors in the unsatu-
rated (vadose) zone and are useful at this stage of an investigation
to characterize a large area. As noted in Scenario A, the survey
involves making a small diameter hole and either inserting a
detection meter probe into the hole, or extracting a sample and
analyzing it on or off site (using an FID, PID, explosimeter, or
Draeger tubes).
Shallow soil samples can be collected to confirm the presence of
contaminants in locations identified during the soil gas survey.
Typically, these shallow samples are collected below the vegetative
mat from depths ranging between 0 and 4 feet.
3.1 Has the soil gas survey been designed for
site-specific conditions?
Design considerations may include the following:
• Spacing of sampling grid — close spacing is better in
dense, clayey materials;
• Depth of holes — deeper holes (e.g., over 4 feet) may be
necessary depending on thickness of soils; and
• Testing methods — on-site analyses can provide imme-
diate results (or "real-time" results) which can be useful
during the layout of the grid.
Soil gas surveys have several limitations that may need to be considered. For
example, they are not as effective when the samples are taken at a distance from
the source. They are also most reliable in permeable soils and have limited
effectiveness in clayey soils. Furthermore, soil gas surveys can have limited
results detecting older plumes whose more volatile compounds may have either
evaporated, dissolved, or degraded.
V ..
3.2 Have shallow soil samples been obtained from
strategic locations using an appropriate sampling
technique?
To ensure that accurate, representative data is gathered,
an inspector may want to check that the following occur:
• Using techniques described in Scenario A, Step 2;
• Selecting sampling locations so as not to miss areas of
potential contamination (e.g., near tank Lines and fill
pipes);
37
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• Recording odors and/or other observations in the field
log; and
• Avoiding cleaners (e.g., solvents or gasoline) that could
contaminate samples when cleaning the sampler or
equipment.
Subsurface Soil Sampling
Step 4 Have subsurface soil samples been collected to determine the
vertical extent of contamination?
Subsurface soil sampling is important because it provides informa-
tion on soil characteristics necessary to estimate contaminant
migration pathways, the depth to the water table, and the poten-
tial impact to ground water. Additionally, the data can be used to
estimate the volume of contaminated soil which is useful when
selecting clean-up alternatives.
Typically, field screening methods are used during soil sampling,
although in some cases, laboratory analyses may be desired. See
Exhibit 9 for more information on laboratory analyses and Exhibit
10 for examples of analytical options available for collected
samples.
Some of the devices available for subsurface soil sampling include
backhoes and clamshells for excavating test pits, and bucket
augers, hollow stem augers, and other drilling methods for soil
borings. (See Exhibit 11 for a summary of drilling methods.)
4.1 Have the following general sampling procedures
been used for collecting subsurface soils from test pit
excavations?
• Obtaining samples by using a clamshell or a backhoe
(since entering an open excavation is hazardous);
• Collecting soil sample(s) from designated depths and
locations of changes in strata;
• Using the general procedures described in Substep 3.2
of this scenario and in Scenario A, Step 2;
• Using a field screening meter to measure hydrocarbon
vapors in the headspace of soil jars; and
• Completing test pit field notes, including information on
location, orientation, and dimensions of excavation, as
well as soil stratigraphy and screening results.
38
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EXHIBITS
Laboratory Analysis of Samples
Field screening for hydrocarbon vapors provides enough information to determine the presence
of contamination and the relative concentration. In many cases, screening information may be
sufficient for decision-making purposes, for example, when there is no uncertainty about the
type of contaminant (i.e., the source is from a known spill or identified leaking tank). There
are instances, however, when laboratory analyses may be desired during an investigation. For
example, analytical data from a laboratory may be used for the following reasons:
• To determine if a potable water supply has been affected and the need for an
alternative water source;
• To identify contaminants that cannot be detected (or differentiated) by field screening
techniques; and
• To meet State and local requirements (e.g., for verification of a cleanup).
Given the cost and time associated with laboratory analyses, it is important that certain meas-
ures are taken to ensure accurate results. In order to avoid resampling (which results in
unnecessary delays and expenses), inspectors should be aware of the following common mis-
takes and possible solutions:
Mistakes
Solutions
Selection of inappropriate type of
analysis
Consult with the laboratory and exist-
ing guidelines for recommended analy-
ses. See Exhibit 10 for a summary of
some common analytical options
Use of improper container and pre-
servative
Consult with laboratory and use con-
tainers that they have approved and/or
provided
Samples unusable due to breakage or
cross-contamination
Collect duplicates or triplicates; place
field blank in storage container with
samples
Samples unusable due to improper
storage and excessive holding time
Arrange with laboratory ahead of time
for analysis to be run as soon as pos-
sible after delivery; store samples in
ice-filled cooler immediately following
collection
Analytical results indicate improper
labellin or samle misidentincation
Label samples very carefully in the
field and; carefully fill out chain of
custody forms prior to delivery to the
laboratory
Source: ICF Inc.
39
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QlMriO
Analytical Options
ANALYTICAL METHODS
GENERAL DESCRIPTION
APPLICABILITY
LIMITATIONS
TOTAL PETROLEUM HYDROCARBONS
(TPH, PHC, or TRPH — for recoverable
hydrocarbons)
1 Uses GC/FID analysis to measure concentration
of total petroleum hydrocarbons extracted from
sample using a solvent
' Must specifically request "fingerprint" analysis
for identification of types of petroleum
hydrocarbons
• Can be used to analyze water and soil samples
• Most applicable for determining presence of oils
(i.e., fuel oil, waste oil)
• Can provide information on "weathered" product
• Should specify if analysis of dissolved fraction of
ground water is desired
• Need to specify to laboratory the type of data
desired
• Possible to use to identify presence of gasoline
product but loss of gasoline can occur during
extraction
• Identification of product types can be approxi-
mate unless samples of pure product (i.e., from
the suspected source) are analyzed
INFRARED
(IR—EPA Method 418.1)
1 Measures concentration of total petroleum
hydrocarbons extracted from sample using freon
• Can be used to analyze water and soil samples
• Most applicable for determining presence of oils
• Can be used to measure lighter oils
• Does not provide identification of types of hydro-
carbons
• Subject to interference since analysis also
measures non-petroleum hydrocarbons
(e.g., organic acids)
• Possible for gasoline sites, however, up to 1/2 of
total gasoline concentration of the sample can be
lost during extraction
OIL AND GREASE (Standard Method 603)
• Measures weight of oil and grease extracted
from sample using freon
• Can be used to analyze soil and water samples
• Better for heavy oils
• Inappropriate for gasoline or oils with volatile
fraction (e.g. waste oils with solvent contamina-
tion) due to loss of volatiles during extraction
GAS CHROMATOGRAPHY (GC)
(EPA Method 602-water; EPA Method 6020-soil)
• Measures purgeable aromatics (volatile fraction)
using purge and trap method
• Provides data on benzene, toluene, ethyl
benzene, and total xylenes (BTEX). (May need
to request xylene data specifically.)
• Compound I.D. is not definitive, i.e., compared to
mass spectrometry (MS) results which are
verifiable
• Good for gasoline
• Can detect some solvents in waste oils
1 Not optimum for fuel oils, particularly heavier
oils, since those compounds lack significant
volatile fractions
GC
(EPA Method 601-water, EPA Method 8010-soil)
1 Measures purgeable halocarbons using purge
and trap method
1 As with Method 602, compound I.D. cannot be
confirmed
' Best for detecting presence of solvents in waste
oils
• Not applicable for petroleum hydrocarbons
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EXH
10
Analytical Options
(continued)
ANALYTICAL METHODS
GENERAL DESCRIPTION
APPLICABILITY
LIMITATIONS
GC/MASS SPECTROMETRY (MS)
(EPA Method 824-water, EPA Method 8240-soil)
• Measures purgeable halocarbons and aromatic*
• Provides positive identification of BTEX
constituents
' Most applicable for gasoline
1 Not optimum Tor fuel oils (particularly heavier
oils) since those compounds lack significant
volatile fraction
GC/MS (EPA Method 625-water;
EPA Method 8270-eoil)
• Measures acid extractable semi-volatile organic • Applicable for sites with diesel oil contamination • In general, limited applicability at petroleum
compounds UST sites
LEAD (EPA Method 239.2 or
Standard Method 304)
• Measures concentration of metal extracted using
a slightly acidic distilled water solution
• Can be used for water and soil samples
• Generally used for gasoline
• Also applicable for waste oils
1 Data on lead concentration in background
samples useful to assist with interpretation
NOTES:
however, they are typically only used for analyzing soils.
For UST sites,
There is currently no one standard method available for quantitative identification of petroleum products in soil and water samples, therefore, it is important to work closely with a
laboratory when selecting analytical methods for a specific site.
Source: Adapted by ICF Inc.
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[EBIT 11
Well Drilling Methods
DRILL TYPE NORMAL DIAM. MAX. DEPTH
HOLE
AVERAGE TIME NORMAL EXPENSE
PER HOLE
ADVANTAGES
DISADVANTAGES
1. Rotary
4--20"
Unlimited
Fast
Expensive
1. Good for deep hotel
2. Can be vised in soils and relatively soft rock
3. Wide availability
4. Controls caving
1. Need to use drilling fluid
2. Potential bore hole damage with drilling fluid
3. Requires drilling water supply
2. Stem Auger 4"-8"
30-50 a.
Fast under suitable Inexpensive to
soil conditions moderate
1. Widely available
2. Very mobile
3. Can obtain dry soil samples while drilling
1. Difficult to set casing in unsuitable soils (caving)
2. Cannot penetrate large stones, boulders, or bed rock
3. Normally cannot be used to install recovery wells
3. Hollow Stem 4"-8"
Auger
30-50 ft
Fast under suitable Inexpensive to
•oil conditions moderate
1. Good for sandy soil
2. Can set casing through hollow stem
3. Very mobile
4. Can obtain dry soil samples and split-spoon
samples
5. Controls caving
1. Casing diameter normally limited to 2"-3* outside
diameter
2. Cannot penetrate large rock, boulders, or bed rock
3. Limited availability
4. Normally cannot be used for recovery wells
4. Kelley Auger 8'-48"
0. Dug Wells Unlimited
90ft
Fast
Moderate to expensive
1. Can install large diameter recovery wells
2. Drills holes with minimum soil wall
disturbance or contamination
3. Can obtain good soil samples
1. Large equipment
2. Seldom available in rural areas
3. May require casing while drilling
5. Bncker Anger 12"- 72"
6. Cable Tools 4'- Iff
7. Air Hammer 4M2"
8. Casing Driving 2"-24"
(well point)
90 ft Fast Moderate to expensive
Unlimited Slow Inexpensive to
moderate
Unlimited Fast Expensive
60 ft Slow to moderate Inexpensive
1. Can obtain good soil samples
2. Can install large diameter recovery wells
1. Widely available
2. Can be used in soil or rock
1. Fast penetration in consolidated rock
1. Very portable
2. Readily available
1. Hard to control caving
2. At times must use drilling fluid
3. Normally very large operating area required
1. Slower than other methods
2. Hole often crooked
3. May require casing while drilling
1. Inefficient in nnconsolidated soil
2. Very noisy
3. Control of dust/air release
4. Excessive water inflow will limit use
1. Limited to nnconsolidated soil - cannot penetrate
large rocks, boulders, bedrock
2. Difficult to obtain soil samples
3. Generally inefficient method to install recovery well
10-20 ft
Fast
Inexpensive
1. Readily available
2. Very large diameter hole easily obtained
1. Caving can be severe problem
2. Limited depth
3. Greater explosive hazard during excavation into
hydrocarbons
Source: Reprinted courtesy of the American Petroleum Institute, "Underground Spill Cleanup Manual" Publication #1628, First Edition, June 1980.
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STOP
It may be necessary to consider the following before using test pits at a site:
• Test pits can disrupt normal site operations, and if left open, pose a safety
hazard to persons and vehicles. Therefore, they are probably most applicable
at large, undeveloped sites.
• Test pits are of limited value where contamination is expected to extend
below the reach of the equipment (i.e., generally 15 to 20 feet).
• Volatilization of contaminants from open excavations can result in an
increased short-term exposure pathway (e.g., to equipment operations).
EXHIBIT 12
Split-Spoon Sampler
4.2 When collecting samples from soil borings, have soil
sampling procedures been consistent?
A split-spoon sampler is one of the most common devices
used for collecting a soil sample from a soil boring or test
hole. As depicted in Exhibit 12, the split-spoon is a steel
tube that can be opened to observe and collect an undis-
turbed soil sample. An inspector should be aware that
subsurface sampling involves the following general proce-
dures:
• Collecting samples from designated intervals depending
on the desired information (e.g., every 5 or 10 feet,
continuously, or at strata changes);
• Recording the number of hammer blows while the split-
spoon sampler is being driven to determine the density
or hardness of the soils;
• Noting any loss of soil during sampling (that is, the
sampler may have penetrated 2 feet but only 1 foot of
soils may have been recovered);
• Using a sharp edge to scrape across the length of the
sample, and noting any changes in strata;
• Placing the samples in the proper containers immedi-
ately, capping them, and ensuring that they are air-
tight;
• Placing all containers in an ice-packed cooler after sam-
pling until it is time to screen soils or send them to a
laboratory for analyses;
PLASTIC BASKET
(INSERTED IN NOSE
OF SPOON TO PREVENT
LOSS OF SAMPLE)
Source: ICFInc.
43
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Classifying the soil type according to the designated
system, and noting any moisture, discoloration, odor, as
well as field screening results; and
Completing soil boring logs in accordance with standard
engineering practices associated with the particular
technique (see Exhibit 13). Include depth to ground
water if encountered during drilling.
Evaluation of the Extent of Contamination
Step 5 Have soil data been accurately evaluated in order to determine
the extent of contamination and the need to continue to
Scenario C?
The information on soil characteristics and contaminant concen-
trations (gathered during Steps 3 and 4 of this scenario) needs to
be compiled and evaluated in order to determine the lateral extent
of contamination. Information on the vertical extent of contamina-
tion and the depth to the water table can be used to determine the
likelihood of impact to ground water.
5.1 Did an evaluation of the soil data include the follow-
ing, if applicable?
• If additional contaminants are found, determining
v whether or not they represent an isolated occurrence or
relate to a separate problem which may require addi-
tional investigation;
• Comparing the screening and analytical results with
background samples from areas that are not suspected
of contamination;
• Plotting the screening and analytical data on a site plan
to delineate the lateral extent of soil contamination; and
• Determining if additional sampling is necessary based
on existing data gaps.
5.2 Did a determination of the potential impact to
ground water include the following, if applicable?
• Determining depth to the water table from ground
surface based on observations from test pits or borings,
or estimates from local/regional hydrogeologic data;
44
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PlVHlKIT 13
Typical Boring Log
PROJECT/LOCATION
PAGE / OF £_
CONTRACT CODE LOGGED BY
DRILLER DATE (START) H/2-8/«q (FINISH) 1 1/28/OT
BORING NUMBER M\V-/ BORING DIAMETER 3 3/s"
EQUIPMENT TYPE DRILLING FLUID USED IVON/E.
CASING , SAMPLER (joOn GROUND WATER
SIZE (H.TA) 33/S TYPESfl/ifSooon (2M') DATE Cf>mal?1,r,n TIME IkOO DEPTH /7.£>'
HAMMER Ib. HAMMER MO Ib. DATE / 2. /*7 7 5?9 TIME f /UA»/-^5DEPTH /? ?•
FALL
DEPTH
(FT.)
0-2
V-7
/0-/Z
/T-/7
20-22
27-27
30-32
FALL 3O~ GROUND "ELEVATION/DATUM
SMPL
S-l
5-2
5-3
5-V
5-6
5-7
REC.
2V
12"
2i'
BLOWS/6"
1*4 - ID
/ " O
/T 1^7
10-20
ZO-/8
10- 28
50-ZO
I-Z
3-6
DESCRIPTION
Med»uiTt c/finge, c)F&y i medium \
"to coarse. GRAVE. L
Loose. , qr*y. SILT and CLAY
Ifttk -fine. sand.
Medium dense, qray,5/l_T
doct CLAY, trace GRAVEL
Dense , white, medium to
Coarse. 5A/VD «9nc( GfZhrfeL,
UWe C/ayey Si/t
Vfry denSC , or&nCjC brovvn,
medium "to coarsfi S A/VO <9ic(
G^A V£TL , //tt/e ClayzySiH'
Soft , or&y , C^-AVe»no(
S/LT
Medium dense. qray CLAYandSlLT
BoTTom at 32 '
EQUIPMENT /J}
INSTALLED W
P
— ^
'.•'•'•'•
1
•X
O-IO'
0-lf
2-PVC
Riser
\0-I2'
Seal
p'i ftef
Pact
SCREENING RESULTS
/REMARKS /5)
(/>p *H J >**^
20
3
-f
0
0
0
SIGNATURE CHECKED BY
NOTES: 1. Wells were constructed innediately following drilling using a 2" diameter, schedule 40 PVC,
with .01" slotted screen, bentonite pellets, cement, and clean sand. All wells were
finished with a locking well cap and protective cover.
2. Field screening results represent total organic vapor levels measured with an HNu Model PI
101 phot oionizat ion detector, in the headspace of soil gas.
3. Grounduater encountered at 20' during drilling.
Source: IGF Inc.
45
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• Developing a vertical profile showing soil stratigraphy
and contaminant concentrations from samples;
• Considering other factors such as the solubility of the
contaminant, porosity and adsorptive capacity of the
soils, precipitation, and approximate amount of con-
taminant released (if known); and
• Proceeding to Scenario C if impact to ground water is
likely to occur or may have already occurred.
Source Control and Soil Management
Step 6 Have effective clean-up measures been taken to control the
source (if applicable) and to manage contaminated soils?
Source control most often involves removal of product from the
leaking tank system, tank removal, tank closure, or tank repair.
See Appendix C for more information on these activities. Once the
source of the release has been adequately controlled, soil manage-
ment usually begins. Inspectors may need to ensure that the
following three basic steps have occurred in the soil management
process.
6.1 Has a determination been made as to what extent
soils need to be managed based on State require-
ments and criteria?
Examples of criteria used to determine cleanup include soils
that are saturated (as measured by a paint filter test) and
soils that exceed an established concentration level.
6.2 Have treatment or disposal methods been carefully
selected and implemented?
These options include excavation and disposal, enhanced
volatilization, soil venting, incineration, and biodegrada-
tion. (See Exhibit 14 for general descriptions of these
technologies.)
6.3 Has the cleanup been confirmed to ensure that the
goals or criteria have been met?
This may involve verification sampling to determine if
treatment has met target clean-up levels as determined by
the State. Such levels may be set based on background
conditions, established concentrations, or groundwater
criteria.
46
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Soil Management Options
TECHNIQUE
GENERAL DESCRIPTION
ADVANTAGES
DISADVANTAGES
EXCAVATION AND DISPOSAL
• Conventional construction equipment (e.g., backhoe) is
used to excavate and remove soils.
• Often done in conjunction with tank removals.
• Disposal options include approved landfills, asphalt
batching plants, landfarming or other treatment facilities.
• Relatively quick and common.
• Allows pollution problem to be removed from the
site.
• Disrupts the site (excavating adjacent to buildings is
not recommended).
• Increases short-term exposure pathway to volatile
hydrocarbons.
• Disposal options may be limited by facility acceptance
criteria and space availability.
• Depth of excavation limited by equipment and presence
of ground water.
ENHANCED VOLATILIZATION/
LANDFARMING
• Contaminated materials are excavated and spread over
the ground surface.
• Volatilization and degradation mechanisms are enhanced
(e.g., by tilling or scarifying the soil and/or adding
sorbents).
• Feasible when open land is available (usually UST
site owner's land).
• Organic soils and temperate climate conditions
facilitate treatment.
• Can require air and soil monitoring.
• Land availability limits use.
VENTING (IN SITU)
• Fane or vacuums are used to create a pressure gradient
that forces air through the soils.
1 Vapors are directed to a vent and released with or without
treatment
1 Feasible at moat sites where trenches or wells can
be installed.
1 Design can account for less permeable soil
conditions (e.g., by vent spacing).
• Can take time (e.g., several weeks or more) to install
and complete.
• Air monitoring and treatment permits may be required.
INCINERATION
• Thermal destruction of contaminants in excavated soils
can be achieved by a variety of types of available
incinerators (e.g., rotary kiln, liquid injection, or circular
bed).
> May be particularly beneficial at sites where petro-
leum products are mixed with other types of
contaminants.
' Mobile unite are available and can be set up on site
for long-term projects.
• Liability perceived by some when soils mixed with
other waste types in the incinerator. (This can be con-
trolled by segregating materials).
• Can require significant permitting (Subtitle C facilities
would meet the permit requirements.)
• Still in the developmental stage.
BIOLOGICAL DEGRADATION
1 Natural microorganisms degrade the contaminants in
soils and can be used during cleanup by monitoring
natural occurrences or by optimizing oxygen and nutrient
conditions.
• Works well in conjunction with groundwater
remediation.
• Best suited for in-situ treatment
• Appropriate as a polishing technique for sites
where other clean-up measures have also occurred.
• Effectiveness limited by microbial population, availabil-
ity of nutrients, temperature, and type of hydro- •
carbons.
• Controlling these factors can be difficult, costly, and
time-consuming.
NOTE: Extensive discussion on these and other technologies has been developed in the existing literature. Please refer to the References for "Remediation* for more information.
Source: IGF Inc.
-------
Reporting Requirements
Step 7 Have owners/operators submitted all information relating to the
cause of the release and the status of the site to the State?
Owners/operators should comply with existing State and Federal
reporting requirements concerning petroleum UST releases. At
this stage of the process, owners/operators will likely be required
to report all data and information that characterizes the site and
the cause of the release (if they have not already done so, see
Scenario A, Step 4 on page 31). Additionally, owners/operators
may be asked by the State to develop a Corrective Action Plan
(e.g., for long-term soil management efforts).
48
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SITE EVALUATION CHECKLIST
SCENARIO B. EXTENSIVE SOIL CONTAMINATION
SITE NAME/ID#:
SITE COORDINATOR:
Date Completed/
By Whom
Step 1: Prior to initiating field work, have all potential sources,
suspected areas of contamination, and site conditions
been identified?
Step 2: Have adequate field preparation measures been taken by
contractors and oversight personnel?
Step 3: Has initial screening been conducted to confirm the presence
of vapors in soils and to identify areas of highest
contaminant concentrations?
Step 4: Have subsurface soil samples been collected to determine the
vertical extent of contamination?
Step 5: Have soil data been accurately evaluated in order to determine
the extent of contamination and the need to continue to
Scenario C?
Step 6: Have effective clean-up measures been taken to control the
source (if applicable) and to manage contaminated soils?
Step 7: Have owners/operators submitted all information relating to the
cause of the release and the status of the site to the State?
Note: Not every task may be applicable in all situations, and the sequence
of steps will vary somewhat from site to site.
49
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SCENARIO C. GROUNDWATER CONTAMINATION
This scenario addresses those sites where groundwater contamina-
tion is likely or has already been identified (e.g., based on visible
product on the surface of the water or analytical results of samples
from drinking water wells). At these sites, a State inspector may
need to evaluate the following:
• Locations of monitoring wells;
• Installation of monitoring wells;
• Characterization of groundwater flow;
• Groundwater sampling procedures;
• Assessment of groundwater contamination;
• Initiation of removal of floating free product from ground
water;
• Determination of the existing and future uses of ground water;
• Provision of additional alternative water supplies if necessary
(temporary alternative water supplies typically would have
been addressed during the initial response phase of the
cleanup); and
• Information relating to the groundwater investigation and
cleanup (in the form of reports and plans) submitted by the
owner/operator to the State.
The purpose of conducting these activities is to determine the type
of contamination (i.e., dissolved or floating product), the extent of
contamination, and the need (if any) to protect additional ground-
water users in an area. Information gathered under this scenario
can help provide the basis for further remediation, as necessary.
The need for some, or all, of these steps is contingent upon
the site-specific situation.
51
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Monitoring Well Locations
Step 1 Have monitoring wells been sited in strategic locations so as
to allow sampling upgradient and downgradient of the
contamination source?
The location of wells should take into consideration the expected
direction and rate of contaminant migration based on permeability
and gradient (see transport discussion in Appendix B). Prior to
siting well locations, it is also beneficial to evaluate the types of
information outlined in the Worksheets as well as data gathered
during soil sampling in Scenarios A or B.
Typically, the direction of groundwater flow in a water table
aquifer will replicate the surface topography. (This is not neces-
sarily true in confined aquifers.) In general, at least one well is
placed in the assumed upgradient direction of the contamination
source, two to three wells are located around the suspected source,
and one or more is installed downgradient to determine the extent
of contamination.
An investigation may also require at least one well to be installed
at depth, below the shallow aquifer, to determine the vertical
extent of migration into a deeper aquifer. The need for a deep well
depends on the site geology, the age of the release, and the type of
contaminants (e.g., "sinker" constituents such as No. 6 fuel oils can
have densities greater than water).
Monitoring Well Installation
Step 2 Have monitoring wells been installed correctly?
Monitoring wells are generally installed in soil borings, upon
completion of drilling, when evidence (e.g., from soil screening)
indicates a release of petroleum product has affected ground water.
(See Scenario B, Substep 4.2 and Exhibit 11 on page 42 for soil
sampling and drilling information.) For well installation purposes,
dry drilling methods are preferable to those using water or mud,
because drilling fluids can influence the quality of the groundwater
sample.
2.1
Have the monitoring wells been designed to meet the
following general criteria, as applicable? (See
Exhibit 15.)
• Well screens have been placed at the depth appropriate
for the information desired. For example:
52
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EXHIBIT 15
Typical Monitoring Well
PROTECTIVE CASING
LOCK
GROUT/BENTONITE
BACKFILL
PVC RISER
W/THREADED JOINTS
BENTONITE
SEAL
PVC SCREEN
W/THREADED JOINTS
CLEAN SAND/
GRAVEL FILTER
PACK
BOREHOLE
ANNULAR SPACE
Source: ICFInc.
53
-------
. the screen intersects the water table when investi-
gating a floating layer;
- the well screen extends sufficiently above and below
the water table in order to account for anticipated
seasonal fluctuations in the groundwater elevation;
and
• the well screen is placed at the depth of primary mi-
gration when investigating dissolved constituents or
"sinkers."
• The well diameter is wide enough to accommodate the
intended sampling equipment. In some cases, however,
small diameter wells will be used to minimize the
volume of fluid that will need to be handled and dis-
posed of during sampling.
• All well materials and sampling equipment are clean or
decontaminated prior to use.
• The well has a bottom cap.
• A filter pack of clean, inert sand or gravel is placed in
the annular space (between the sides of the boring and
the outside of the well). Generally, a sand pack will
extend two to five feet above the top of the well screen.
• Bentonite and/or grout seals are placed at appropriate
depths (i.e., one to two feet above the sand and between
significant strata) to prevent cross contamination
between aquifiers and/or infiltration of sheet runoff
from the ground surface.
• The well was developed upon completion to ensure
proper operation. This is usually accomplished by pump-
ing the well until the water is clear and until the rate of
recovery between pumping is relatively constant. If
gasoline is suspected or known to be present, develop-
ment water must be drummed and handled as hazard-
ous material (until laboratory results are available to
indicate otherwise for suspected ground water).
• The well is equipped with a protective casing or road
box and a locking cap to prevent vandalism.
2.2 Has all pertinent information been recorded on the
boring log as shown in Exhibit 13 on page 45 (or in
the field notebook), if applicable?
54
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2.3 Have well locations and ID numbers been clearly
marked so as to be sufficiently visible in all seasons
(e.g., with colored flags staked into the ground or
with spray paint)? Have well locations been
sketched on a plan, using measured distances from
stationary site features, to allow easy location in the
future by surveyors and field personnel?
Other factors to remember about well installations include the following:
• Delays during installation can occur when the sand filter pack is put in place
too quickly and forms a block or bridge between the well and the interior of
the auger or casing. This is particularly apt to occur when the annular space
is small (e.g., a 2-inch diameter well is placed in a 3.75-inch diameter auger
or casing).
• Bentonite and grout can influence water quality if improperly placed.
Bentonite should be wetted following placement and allowed to set, and grout
should be well-mixed before placement. Interference from poor seals may be
identified (i.e., by elevated conductivity readings from bentonite or by high
pH readings in groundwater samples).
• Piezometers, i.e., monitoring wells whose primary purpose is to obtain water
level data (typically used in clay materials), should be of small diameters
such that head changes can be detected quickly.
• For more information, see the References for "Soil and Groundwater
Investigations."
Groundwater Flow Characteristics
Step 3 Have groundwater flow charactericstics been determined?
In order to verify that wells are properly located both upgradient
and downgradient of the suspected source, the direction of ground-
water flow must be confirmed. To determine if sufficient data are
available on groundwater flow, inspectors may evaluate the
following.
3.1 Have experienced surveyors measured the elevation
of the tops of wells or piezometers?
3.2 Based on the survey, have groundwater elevations
been calculated? (For this calculation, it is best to
use water table measurements that were all collected
on the same day.)
55
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3.3 Have elevations been plotted on a groundwater
contour plan to determine:
• Direction of flow (perpendicular to the groundwater con-
tour lines); and
• Hydraulic gradient (the distance between contour lines
divided by the change in groundwater elevation)?
Elevation data from shallow and deep aquifers should be
examined separately. This is important since the direction
of flow in a deep aquifer may differ from, and can actually
be the opposite of, the flow in a shallow aquifer.
3.4 Were data available on hydraulic conductivity and
porosity of the soil (to estimate groundwater velocity
or the rate of flow)? (See Appendix B for one method
to calculate flow rate.)
Information on hydrogeologic characteristics of a site can be
obtained from review of available literature or direct aqui-
fer testing such as pump tests and slug tests (i.e., rising
head and falling head tests). This information is important
for estimating how quickly downgradient drinking wells
may be affected as well as for future selection of treatment
options.
Groundwater Sampling
Step 4 Have groundwater sampling procedures been correctly
implemented?
Inspectors may want to review sample collection procedures to
ensure that representative groundwater samples have been col-
lected and no cross contamination occurred at the site.
4.1 If samples are to be sent to a laboratory, have the
appropriate types of analyses been identified prior
to sample collection? (See Exhibit 9 on page 39 for
more discussion of laboratory analyses.)
The chosen laboratory analyses should provide data on the
indicator parameters for the released product. For
example, benzene, toluene, and xylene are major constitu-
ents of gasoline, and lead is an indicator parameter for
regular, leaded gasoline. The type of analysis will influence
56
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how a groundwater sample is collected. Different analyses
require different volumes of water and types of containers.
(See Exhibit 10 on page 40 for additional information on
analytical options.)
4.2 Were the necessary measurements obtained prior to
purging the well to remove stagnant well water?
This may include the following:
• Using a weighted tape or electric water level reader to
determine the depth to the water table from the top of
the casing and/or ground surface (see Exhibit 16); and
• Determining the presence of floating free product on the
water table. This determination may be made using a
weighted tape with hydrocarbon detection pastes, an oil/
water interface probe, a clear bailer, or obtaining a
sample from the water table with a standard bailer.
The inspector should recognize that the thickness of floating product observed in
a well is often greater than the actual thickness in the rock formation due to the
influence of the well diameter and the capillary fringe. Product thickness in a
well may also fluctuate seasonally and may even decrease to zero when the
water table is high.
When a floating product layer is present, measurements of depth to the water
table need to be corrected to account for the density difference of the product
relative to water. For example, gasoline has a density approximately 75 percent
that of water. Therefore, if a one-foot floating layer was present, 0.75 feet should
be added to the elevation of the water/gasoline interface to obtain the true water
table elevation.
4.3 Has the appropriate purging equipment been
selected based on the depth to the water table,
amount of water, well diameter, and the volume of
water to be removed (usually three to five times the
water standing in the well)? (See Exhibit 17 for more
information on purging equipment).
4.4 Were well water purging techniques satisfactory?
This may entail the following:
• Operating pumping equipment in accordance with
manufacturer's instructions, or bailing the well a desig-
nated number of times using clean tubing and/or
bailers; and
57
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EXHIBIT 16
Method to Determine Water Table Elevation
and Product Thickness
(B) MARKER DEPTH =
READING ON TAPE LEVEL WITH
EDGE OF CASING. USE AN
EVEN FOOT FOR CONVENIENCE.
(A) CASING ELEVATION =
ELEVATION ON TOP OF
CASING DETERMINED FROM
SURVEY.
GASOLINE FINDING PASTE
/(C) FLUID CUT =
FOOTAGE READING OF
FLUID MARK ON TAPE.
j?V»£;~sJL*L*U^»w.*,'
* V^WATER^N^NG PASTE
...
I I !..!,
^DJWTERCirH .„,%" * v/
•^ V -^ fjf'™ *•• siv ••. ^f" "• *"" -.S
- f ^ '{&•>'**'' ' t
.. * i " ',, <» s "f ' ^ - "?
''*'*"/,''% *•?" --' - -V
,/ - ,; ',;/ ->4
' ,", ' * ' "f, •. ,is ^
f ^" 4*' \f- s'tf,"***"' •&'"i"
.•^ $ f I *•• \ •$ t
^ *? *y ^ P %\ f t vx ff
f fp f '_,/•• S f * •'^ «" * / A,
* / s < ^ -^ ' *f . •=• ' ^
s. X *" •*'•* •*s"\ f ff f ff f f ff f f f f ffff f
<"•!£ £.• '5'-!' X" f %" ffffff f f$ f fff ff f tyf f
&,&, **•$£*«•£ ,',\'A, ,\st," '»-
*"-' ,^ -^''{\,'''\,f/^ "' '-'"'
\t <*••• sv&vv v. s 's ^ "*% '*•. •*•. •"• *• ^ '
—WEIGHT '- s- >, --'-„ s,' ^ /V;
,*Ttc~.r i ^;, y ,f/
* V ' J ," - -- 'tf
f , A ' '' ' ••
fz "•* * •. * " s ^ '
J* «> , - .-V 's *' < * t > •. i
^^'-'^S^^i^^L
'* PRODUCTION ELEVATION = A = (B
I WATER ELEVATION = A = (B - D)
i '5
- C) ^
58
Source: Reprinted courtesy of the American Petroleum Institute, "Underground Spill Cleanup
Manual," Publication #1628, First Edition, June 1980.
-------
EXHE81T17
Purging Equipment
Diameter Casing
Bailer
Peristaltic Pump Vacuum Pump Airlift
Diaphragm Submersible Submersible Submersible Electric
Trash* Pump Diaphragm Pump Electric Pump Pump with Packer
1.25 Inch
Water level <25 ft
Water level >25 ft.
2-inch
Water level <26 ft.
Water level >25 ft.
4 inch
Water level <26 ft
Water level >26 ft.
flinch
Water level <2B ft.
Water level >25 ft
Binch
Water level <25 ft.
Water level >25 ft.
Source: Barcelona, M.J., J.P. Gibb and R.A. Miller. A Guide to the Selection of Materials for Monitoring Well Construction and
Groundwater Sampling. ISWS Contract Report 327, Illinois State Water Survey, Champaign, IL. 1983.
en
-------
4.5
• Disposing contaminated discharge water and free
product appropriately. Options include treating
discharge water on site (using an air stripper and/or
carbon adsorption system), discharging to the sewer if
allowed (a permit may be required), or collecting and
hauling off site. Refer to the appropriate State regula-
tory standards for guidance.
Purging and sampling may be complicated if free product is
present. Common options include the following: choosing
not to sample; bailing, followed by use of sorbent material
to swab the floating product off the surface of the well
water; and installing dedicated wells/samplers below the
free product (e.g., a cluster well or a gas-driven sampler
which can be isolated to collect from a specific depth).
Have samples been obtained using the appropriate
equipment and collection method?
Following the recharge of the well, samples should be
collected using a pre-cleaned bailer (e.g., stainless steel,
TeflonfR], or polyvinyl chloride — PVC) attached to a clean
cable. (Samples obtained from a pump can compromise the
quality of results since volatilization can occur prior to
sampling.)
The quality of groundwater samples can be affected by the following:
• Excessive turbulence during sampling;
• Inadequate cleaning of sampling equipment (bailers) between wells;
• Incorrect selection, use, and labelling of sample containers; and
• Insufficient temperature and quality control during sample handling
(e.g., samples should be transported and stored in ice-packed cooler).
4.6 Has all pertinent information been recorded in a
field notebook and on the labels?
Typically this includes well number, date, time, sampler,
project name/ID#, and for laboratory analyses the type of
preservative and analytical method should be identified.
60
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Assessment of Groundwater Contamination
Step 5 Has an accurate assessment of groundwater contamination been
made?
Based on the analytical results, a determination can be made
about the presence and extent of groundwater contamination.
This assessment is necessary to help determine the need for addi-
tional sampling, protection of additional groundwater users, and/or
cleanup.
Consult with State drinking water offices to determine if contami-
nation levels exceed their criteria. Additionally, sample results
can be compared to background data (representative of conditions
around the site). The site data may then be plotted on a site plan
to delineate the limits of the contaminant plume.
If a nearby downgradient stream or river exists, it may be a good idea to collect a
surface water sample. The results can provide valuable information on the
downgradient extent of a plume assuming the ground water and surface water
are interconnected (i.e., the ground water discharges to the stream).
Free Product Removal from Ground Water
Step 6 Has an effective means of removing free product from ground
water been initiated?
To prevent free product from acting as an ongoing source of
groundwater contamination (or flammable vapors which could lead
to a health and safety hazard), free product removal can be
implemented.
Generally, the preferred free product recovery technologies are the
trench method and the recovery well method. Barriers may also
be used in conjunction with recovery systems to enhance their
effectiveness. For more information, see Exhibits 18,19, and 20
and the References for "Remediation."
61
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EXHIBIT 18
Free Product Recovery
Option A: Trenches or drains
Trenches function as relatively simple passive systems for the collection of free product (see
Exhibit 19). They are particularly effective at sites with shallow ground water (at depths less
than 10 to 15 feet), in open areas, and in soils with low permeability (e.g., 10"7 cm/sec). To
determine if a trench has been properly located and installed, it is necessary to review the
following: the depth to ground water; the direction of flow; observations of product ponding in
the trench; the effect of any pumping of water from beneath the product; the length of the
trench; and the soil conditions. (Crushed stone or gravel may need to be added for support in
long-term trenches.)
Option B: Recovery wells
Recovery wells can also be used as retrieval systems and are best suited for confined spaces,
where ground water is at depths greater than 20 feet, and where soils have moderate to high
permeabilities.
When a single pump system is used, the drawdown created during pumping needs to be suffi-
cient to control contaminant migration. Storage, treatment, and disposal of the removed fluids
(which are a mix of product and water) must be addressed in accordance with State and Fed-
eral requirements. Special permits may be necessary for managing removed fluids
(see Exhibit 19).
Dual pump systems employ separate pumps for water and for product and therefore reduce the
amount of contaminated water which must be handled. As a result, these systems are advan-
tageous for large volume spills (see Exhibit 19).
Option C: Barriers
As part of the retrieval system, barriers may be necessary to minimize withdrawals of large
volumes of water (see Exhibit 20). Barriers may include:
• Sheet Piles - Due to substantial costs involved and unpredictable wall integrity, sheet
piles are generally used for temporary dewatering during other construction efforts or
as erosion protection where some other barrier, such as a slurry wall, intersects flowing
surface water.
• Grouting - Generally used to seal voids in rocks.
• Hydraulic barriers - Can be used at sites directly over moderate or highly productive
aquifers, as well as those with low permeability soils, as part of a manifolded system
with automated controls.
• Slurry walls - Installation can be less expensive than alternatives. Most applicable at
sites where the wall depth will be less than 80 feet; also, presence of bedrock or imper-
meable layer is beneficial for "keying" or connecting the bottom of the wall.
For more information see References for "Remediation".
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Source: IGF Inc.
62
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HXHIHIT 19
Trenches and Recovery Wells
Cross Section of Interceptor Trench 1
Single Pump System 2
OIL-WATER SEPARATOR
OIL
WATER
WATER LEVEL
WHEN PUMPING
CONCENTRATED
FREE PRODUCT
GASOLINE-WATER
PUMP
Dual Pump System 2
CONCENTRATED
FREE PRODUCT
WATER TABLE
COMPRESSION PUMP
PRODUCT RECOVERY PUMP
Sources: 1. Reprinted courtesy of the American Petroleum Institute,"Underground Spill Cleanup
Manual," Publication #1628, First Edition, June 1980.
2. Cleanup of Releases from Petroleum USTs: Selected Technologies. U.S.
Environmental Protection Agency, April 1988.
63
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EXHIBIT 20
Barrier Installations
Plan View of Barrier with Recovery Well1
DITCH
IMPERMEABLE
BARRIER
RECOVERY
WELL
One-Sided Subsurface Drain with Clay or Plastic Barrier2
UNDERGROUND
TANK
SUBSURFACE DRAIN
WITH CLAY OR
PLASTIC BARRIER
ORIGINAL WATER
TABLE
CLEAN WATER
RECHARGING
FROM STREAM
LOW PERMEABILITY
64
Sources: 1. Reprinted courtesy of the American Petroleum Institute.'TJnderground Spill Cleanup
Manual," Publication #1628, First Edition, June 1980.
2. Underground Storage Tank Corrective Action Technologies. U.S. Environmental
Protection Agency, reprinted from JRB Associates, January 1987.
-------
Determination of Groundwater Uses
Step 7 Have both the existing and future uses of ground water been
determined to further identify the potentially affected
community?
Before deciding if additional alternative water supplies are
necessary, inspectors may need to complete or review an
assessment of ground water use.
7.1 Have the designated or planned uses of the ground
water been determined?
This may involve the following:
• Checking the State classification system;
• Reviewing regional and/or local classification systems
and planning documents; and
• Identifying special restrictions pertaining to the
designation.
7.2 Has existing groundwater use been evaluated by
checking new information against that gathered in
Chapter n, Initial Response, Step 6 on page 16?
Alternative Water Supplies
Step 8 Have additional alternative water supplies been provided, if
necessary?
Depending on the extent of contamination and the feasibility of
aquifer restoration, a temporary and/or emergency water supply
may be needed until a permanent alternative water supply is
found, or until the existing supply is restored. (See Chapter II,
Initial Response, Step 7 on page 17 for more information on
temporary alternative water supplies.)
If the situation is such that the existing water supply is irrevoca-
bly damaged, permanent alternative water supplies may be pro-
vided by one of the following techniques:
• Blending the existing municipal water supply with an alterna-
tive supply;
65
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• Purchasing a new municipal water supply from a neighboring
unit;
• Providing a new central municipal system using a surface
water supply;
• Developing a new groundwater well for municipal or private
• supply systems; and
• Determining the feasibility of extending municipal water
supply lines or developing new wells or surface water sources
as alternatives for private wells.
Reporting Requirements
Step 9 Have owners/operators submitted all information relating to the
groundwater investigation and cleanup to the State?
Owners/operators should comply with existing State and Federal
reporting requirements concerning the investigation and subse-
quent remedial activities associated with groundwater contamina-
tion. Owners/operators should report the steps taken to delineate
the extent of contamination, the estimated quantity, type, and
thickness of free product observed and measured, the type of
recovery system, and the extent of free product removal. Addition-
ally, owners/operators may be required to develop a Corrective
Action Plan for responding to contaminated ground water.
66
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SITE EVALUATION CHECKLIST
SCENARIO C. GROUNDWATER CONTAMINATION
SITE NAME/ID#:
SITE COORDINATOR:
Step 1: Have monitoring wells been sited in strategic locations so as
to allow sampling upgradient and downgradient of the
contamination source?
Step 2: Have monitoring wells been installed correctly?
Step 3: Have groundwater flow characteristics been determined?
Step 4: Have groundwater sampling procedures been correctly
implemented?
Step 5: Has an accurate assessment of groundwater contamination
been made?
Step 6: Has an effective means of removing free product from
ground water been initiated?
Step 7: Have both the existing and future uses of ground water
been determined to further identify the potentially
affected community?
Step 8: Have additional alternative water supplies been provided,
if necessary?
Step 9: Have owners/operators submitted all information relating to
the groundwater investigation and cleanup to the State?
Date Completed/
By Whom
Note: Not every task may be applicable in all situations, and the sequence
of steps will vary somewhat from site to site.
67
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APPENDICES
A. VAPOR CONTROL AND TREATMENT OPTIONS
B. TRANSPORT OF CONTAMINANTS
C. TANK REMOVAL, CLOSURE, AND REPAIR ACTIVITIES
69
-------
APPENDIX A -- VAPOR CONTROL AND TREATMENT OPTIONS
Passive and active vapor control systems can reduce the hazards
associated with hydrocarbon vapor migration. These systems are
designed to enhance or create a pressure gradient which causes
the vapors to flow to a desired collection area (trench or well).
From the collection point, vapors are then either released or
treated (e.g., by adsorption or catalytic conversion).
It is important to remember that the first steps in any vapor
control effort involve the following precautionary measures:
• Using explosion-proof equipment;
• Eliminating ignition sources; and
• Posting warning notices for security.
With both types of systems, inspectors need to be aware of the
following:
• Worker health and safety controls are a consideration during
installation;
• Preliminary testing may be necessary prior to design; and
• Periodic monitoring of subsurface vapors (and pressure for
active systems) may be needed to ensure effectiveness.
Passive Vapor Control Systems
Passive vapor control systems typically involve the installation of
trenches or wells just outside the area of contamination. The
trenches may be open or filled with permeable crushed stone.
Perforated pipes and vent stacks may also be installed. (See
Exhibit A-l.) Passive systems are most suitable for sites where
small volume losses have occurred, soils have high permeabilities,
and a perched water table is not present. Situations where the
temperature of the ambient air is cooler than the soil temperatures
are also suitable for passive systems.
The advantages of passive systems are that they are relatively
quick and easy to install and that they do not require ongoing
operation and maintenance. These systems may be limited,
71
-------
EXHIBIT A-l
Passive Vapor Control System
Vent
' \
J*
..) Perforated Collection Pipe
Monitoring Well
w/Probe
Note: Vent pipe placement varies with the situation. State Fire Marshalls or local fire departments
should be consulted for minimum vent pipe heights.
Source: IGF Inc.
72
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however, by climatic conditions such as heavy rainfall or prolonged
freezing, and by low permeability rock formations. The trench
method also has limited applicability at sites where the depth to
contamination exceeds the capabilities of the equipment
(i.e., approximately 20 feet).
Active Vapor Control Systems
Active vapor control systems force the vapors to collection points
(usually located within the contamination area) through the use of
pumps (positive pressure) or vacuums (negative pressure). The
system includes a series of vapor extraction wells, a gas collection
unit, control valves, a vacuum or blower, and vents (see Exhibit
A-2). Active systems may be used for most site conditions.
The advantages of active systems include: accelerated vapor
removal; relatively quick and easy installation; reliability in heavy
rainfall or prolonged freezing conditions; ability to isolate areas to
be protected; and effectiveness in most geologic conditions (see
Exhibit A-3). Negative pressure systems are also excellent for sub-
slab venting where gravel fill exists. The disadvantages of active
systems include ongoing operation and maintenance requirements,
the potential need for treatment of contaminated air, and the
potential to direct vapors to previously uncontaminated areas
(using positive pressure).
Vapor Treatment Options
Depending on the specific site and State requirements, vapor
treatment technologies may need to be included in the design of an
active control system to further control the emissions of hydrocar-
bon vapors. Two of the more common technologies, adsorption and
catalytic conversion, are described here.
Adsorption
Adsorption systems can be very effective at UST sites if
they are properly designed and maintained. The selection
of a type of adsorption media, i.e., carbon or synthetic
resins, will vary depending on the contaminant. Factors to
consider when designing an adsorption system include
anticipated effectiveness, rate of breakthrough, and dis-
posal/regeneration of the sorption media, as well as the
volume of vapor. The actual adsorption capacity of con-
taminants varies with the material.
73
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EXHIBIT A-2
Active Vapor Control Systems
Inclined Perforated Pipe S&
to Collect Vapors §|
^^^^^^^^m
•ft
-------
EXHIBIT A-3
General Considerations for Active Vapor Control Systems
General Curve for Vacuum versus Soil Permeability
HIGH
VACUUM
LOW
HIGH
PERMEABILITY
LOW
General Scheme for Well-Point Spacing
WIDE
SPACING
CLOSE
HIGH
PERMEABILITY
LOW
Source: Groundwater Technology Inc.
75
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The use of vapor phase carbon as an emergency response
mechanism is generally on a finite short-lived basis.
Normally, for longer duration use, a catalytic converter or
natural diffusion to a soil vent system is more feasible and
cost effective. Some of the general rules for carbon adsorp-
tion include:
• Vapor phase carbon adsorbs approximately 10 percent
by volume of the organics to be collected. Multiple bed
systems can be used to increase contact time.
• A small volume 55-gallon drum portable adsorber has
approximately 5-6 gallons or 30 to 40 pounds maximum
adsorption capacity.
• Under normal vapor input conditions, with 20-50 ppm
voL/vol. and a 200 ftVminute flow, a typical unit might
last 7-10 days before breakthrough.
• Alarms and/or shutdown controls may be necessary for
complex systems, sensitive locations, or populated
areas.
Catalytic Conversion
The catalytic conversion option is an approach for vapor
control at sites with low to high level vapor concentrations.
Typically, a catalytic converter unit consists of three basic
elements — a high efficiency air-to-air heat exchanger, an
air heater (electric), and a precious metal catalyst (see
Exhibit A-4). During operation, the vapor to be treated is
preheated in the heat exchanger and is passed over the
catalyst where combustion takes place. During the design
phase, safety features and monitoring controls are of pri-
mary importance to consider and pilot studies may be
necessary. (Flaring — the process of exposing vapors to an
open flame with no special features to control temperatures
or time of combustion — is another alternative for vapor
control. Design and operating conditions for flaring are not
readily available, however, and it is not a desirable method
for many situations e.g., gas stations or densely populated
areas.)
76
-------
EXHIBIT A-4
Catalytic Converter System
RECIRCULATED
CLEAN HEATED
AIR TO HEAT -^
EXCHANGER
1
1
s
1
f
1
<
4
\
w.
. ELECTRIC
HEATER
w
ATALYST
VENT TO
TMOSPHERE
f^ji
" M— 1
1
1
*•
jtfM
\
V
_
-------
APPENDIX B « TRANSPORT OF CONTAMINANTS
Unsaturated Soils
The rate and pattern of seepage of petroleum products through
unsaturated soils is primarily influenced by the geologic material,
the volume, type of contaminant released, and the amount and
type of precipitation. (Exhibit B-l presents the seepage pattern for
three hydrocarbon plumes.) To estimate the maximum depth of
penetration, the following formula can be applied:
D = RvV
A
where: D = maximum depth of penetration, m; V = volume of
infiltrating product, m3; A = area of spill, m* and Rv = constant for
retention capacity and product viscosity based on the chart below.
TYPICAL VALUES FOR Rv*
Soil
Coarse Gravel
Gravel to Coarse Sand
Coarse to Medium Sand
Medium to Fine Sand
Fine Sand to Silt
Gasoline
400
250
130
80
50
Rv
**
Kerosene
200
125
66
40
25
Light
Fuel Oil
100
62
33
20
12
* Source: Shepherd, W.D., "Practical Geohydrological Aspects of Groundwater
Contamination."
** A constant value representing capacity of soil and viscosity of product.
V J
Saturated Flow
The migration of a plume of dissolved contaminants in the satu-
rated zone is primarily controlled by the characteristics of ground-
water flow. As expressed in Darcy's Law, the quantity of flow (Q)
is a function of the hydraulic conductivity of the soil material (K),
the gradient dh/dl (or I), and the cross-sectional area (A) expressed
as:
Q = KIA
79
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EXHIBIT B-l
Typical Seepage Patterns
Product Seepage
, LAND SURFACE
SLOW SEEPAGE
INTO
PERMEABLE
SOIL
HIGH VOLUME
SEEPAGE WTO
PERMEABLE
SOIL
SEEPAGE INTO
STRATIFIED SOIL
WITH VARYING
PERMEABILITY
Behavior of Product after Spill Has Stabilized
GROUND SURFACE
SOIL CONTAMINATED
BY RESIDUAL PRODUCT
PRODUCT MIGRATING DOWNWARD
AND ACCUMULATING ON WATER TABLE
CAPILLARY ZONE
Typical Behavior in Porous Soil Following a Sudden, High Volume Spill
SOIL CONTAMINATED
BY RESIDUAL PRODUCT
80
Source: Reprinted courtesy of the American Petroleum Institute, "Underground Spill Cleanup
Manual," Publication #1628, First Edition, June 1980.
-------
(See Exhibit B-2 for hydraulic conductivities of geologic materials.)
Using Daley's Law as the basis for further calculations, the rate or
velocity of flow (v) can be calculated as:
where n = porosity.
While Dairy's Law is commonly used to determine ground water
flow characteristics, other factors such as biological degradation,
oxidation, and sorption must also be taken into account when
determining contaminant transport or dispersion. Because these
factors can vary significantly from site to site, dispersion must be
calculated on a site-specific basis.
There are no established dispersion rate values, however, there
are several methods currently used to estimate transport rates on
a site by site basis. The two primary dispersion factors that need
to be considered are the rate of longitudinal dispersion and the
transverse to longitudinal ratio.
• In general, the rate of dispersion increases as the hydraulic
conductivity of the aquifer increases. For example, in medium
grained sands the dispersion rate is greater than in fine
grained silty sands. (This premise may not be valid if a pre-
ferred migration pathway develops, e.g., through cracks in a
clay formation or along subsurface manmade lines.)
• The ratio of dispersion in the longitudinal direction vs. the
transverse direction decreases as the silt and clay content
increases in soils. For example, depending on groundwater
flow velocity, in a medium grained sand the ratio ranges from
approximately 6:1 to 10:1, while silty and clay sands may have
a ratio of about 2:1 to 3:1. (These ratios combine the affects of
biodegradation and chemical degradation.)
For more information see the References for "Soil and Ground-
water Investigations."
81
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EXHIBIT B-2
Hydraulic Conductivity of Selected Rocks
Igneous and Metamorphic Rocks
Unfractured Fractured
Basalt
Unfractured ' Fractured Lava Flow
Sandstone
Fractured Semteonsolidated
Shale
Unfractured Fractured
Carbonate Rocks
Fractured Cavernous
Clay Silt, Loess
Silty Sand
Clean Sand
Fine Coarse
Glacial Till Gravel
I I
10'" 10" 10'10 10"9 10* 107 10* 10* 10* 10* 10* 10'1 1 10
cms -1
I I I I I I I I I I I I I
10* 10"7 10* 10"s 10"* 10"3 10"2 10"' 1 10 10* 103 104
md-1
I I I I I I I I I I I I I
107 10* 10* 10* 10* 102 10' 1 10 102 103 10* 10s
ftd-1
I I I I I I I I I I I I I I
10"7 10* 10* 10* 10* 10* 10'1 1 10 10* 10s 10* 105 10s
gald-'tf2
Source: United States Geological Survey, 1983
82
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APPENDIX C — TANK REMOVAL, CLOSURE, AND REPAIR ACTIVITIES
Tank Removal
The permanent removal or in-place closure of tank systems may be
conducted for a number of reasons, including compliance with
regulations, and as a condition of a real estate transaction. The
determination of whether to excavate and remove a tank perma-
nently, to close it in place, or to repair it depends on a number of
factors, such as the location of the tank, State and local regula-
tions, availability of equipment, labor, materials, and associated
costs. State and local Fire Marshalls should be consulted to obtain
information on specific requirements.
An understanding of tank removal procedures is important, since
site observations made during these removals can often provide
the first direct evidence of leaks and the extent of soil contamina-
tion. The following steps may be followed during a tank removal:
• Drain the product from the piping into the tank;
• Pump the product from the tank;
• Clean residual sludge from the tank;
• Remove the fill (drop) tube; disconnect the product lines and
the fill gauge, and cap or plug all open ends of lines (except
vent lines);
• Eliminate explosive conditions in the tank, e.g.., by placing dry
ice inside (1.5 Ibs. per 100 gallons of tank capacity) or by venti-
lating the tank with air by use of a small gas exhauster;
• Remove the tank and place it in a secure location (i.e., to
prevent movement or obstruction);
• Check tank for explosive conditions;
• Remove soil accretion on the outside of the tank as much as
possible;
83
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Tank Closure
• Check certain parts of the tank for evidence of leakage, i.e., the
seams, the tank bottom (particularly the area beneath the fill
pipe where stick tests frequently hit the tank), and the parts of
the tank which are located near patches of stained soils;
• Plug or cap all openings, except the vent, after vapor removal;
and
• Check for explosive conditions and secure the tank on a truck
for transportation to the disposal site.
Note that, if possible, arrangements for a disposal site should be
made prior to excavation. With the ongoing capacity shortages at
landfills and recent regulations restricting land disposal, it may
take time to finalize an agreement with a disposal site. In those
cases, an open excavation or stockpiled soils could pose unneces-
sary risks during the negotiation period. Similarly, arrangements
should be made for a supply of clean fill or security fencing for a
site before beginning operations.
Managing soils during removal is another aspect of the project
that should be planned. Some States prohibit any contaminated
soils from being placed back in an excavation during a tank
removal, even if more extensive soil removal will need to be
conducted in the near future. In some situations, however, it is
possible to place plastic sheeting between unexcavated contami-
nated soils and new clean fill. This helps facilitate partial separa-
tion of the soils so they can be placed in separate stockpiles when
the comprehensive excavation is conducted.
Tank closure (in place) is often a viable option when a tank
removal would be extremely difficult (i.e., a tank is located directly
underneath a building, and/or removal would severely disrupt a
facility's operations). As with tank removals, in-place closures
involve emptying the tank of all liquids and dangerous vapors and
cleaning out the accumulated sludge. Additionally, a tank closed
in place should be filled with a harmless, chemically inactive solid,
such as sand, concrete or urethane foam.
In order to ensure that a tank being closed in place is not respon-
sible for any contamination, a site assessment must be conducted
prior to the completion of closure activities. If any contaminated
soil and/or ground water or any free product is discovered during
this assessment, the owner/operator will need to report the release
and conduct appropriate clean-up measures.
84
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Tank Repair
Tank repair is an alternative to tank removal or in-place closure.
It is important that the person repairing the tank follow standard
industry codes that explain the correct procedures for repairing
tanks and demonstrating that the tank repair was successful.
This demonstration is usually made by inspecting the tank inter-
nally with an electrical detector. Other methods include conduct-
ing a tightness test or conducting another leak detection test that
is approved by the State regulatory authority. It is also required
that USTs with cathodic protection be tested (within six months)
to determine if the cathodic protection is continuing to work prop-
erly following the construction activities.
For more information on tank removal, closure, or repair activities,
see the References for "Remediation.''
85
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WORKSHEETS
1. SITE HISTORY AND TANK INFORMATION
2. PRELIMINARY REVIEW OF IMPACTS OF RELEASE
3. EVALUATION OF ANTICIPATED SITE CONDITIONS
4. PREPARATION FOR FIELD OPERATIONS
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WORKSHEET 1 — SITE HISTORY AND TANK INFORMATION
SITE NAME/TO*:
SITE COORDINATOR:
DATE/TIME:
SITE LOCATION/ADDRESS:
COUNTY/CITY:.
SITE CONTACT:
TELEPHONE:
NAME AND ADDRESS OF OWNER/OPERATOR(S):
NOTIFICATION (name and date of incident report):
DESCRIPTION OF LOSS:
LOCATION OF TANKS (attach site plan or sketch):
-------
WORKSHEET 1 — SITE HISTORY AND TANK INFORMATION
(Continued)
TANK DESCRIPTION:
Volume
(gallons) Fuel Type
Construction Material
Age
CAUSE OF RELEASE (Circle One):
A
B
C
D
E
Catastrophic
Long-Term Leakage
Overfilling
Unknown
Other — Describe
LOCATION OF FAILURE(S) (sketch on plan):
A Tank
B Lines
C Connections
D Other
E Undetermined
TANK TEST RESULTS (recorded leakage rate, attach results):
INVENTORY LOSS (period of records, percent loss, and volume accounted for):
HISTORY OF TANK USAGE (on site and in the area around the site, e.g., could a removed or
abandoned tank or an off-site tank have contributed to the problem?):
-------
WORKSHEET 1 — SITE HISTORY AND TANK INFORMATION
(Continued)
LOCAL CONTACTS (list individuals to contact):
Department/Affiliation Name Telephone N,\mifof r
FIRE
HEALTH
EMERGENCY RESPONSE/
HAZARDOUS MATERIALS
ENGINEERING
PUBLIC WORKS/WATER
AND SEWER
ASSESSORS
U.S.G.S. AND SOIL SURVEY
SITE EMPLOYEES
NEIGHBORS
Note: Use the attached telephone and/or site inspection logs to record information on: past site
use; availability of maps, soil borings, or well logs; proximity to drinking water supplies; waste
oil disposal practices; and location of underground lines.
-------
TELEPHONE LOG
SITE NAME/TO*:
SITE COORDINATOR:
DATE/TIME:
CONTACT:
DEPARTMENT/
AGENCY:
TELEPHONE NUMBER:
SUMMARY:
i»
-------
SITE INSPECTION LOG
SITE NAME/ID#:
SITE COORDINATOR:
DATE/TIME:
PURPOSE OF VISIT:
SUMMARY OF SITE ACTIVITY:
SIGNATURE
-------
WORKSHEET 2 — PRELIMINARY REVIEW OF
IMPACTS OF RELEASE
SITE NAME/TO*:
SITE COORDINATOR:
DATE/TIME:
CURRENT SITUATION:
AFFECTED AREA (Residential, Commercial, or Industrial?):
NUMBER OF PERSONS AND/OR HOUSEHOLDS WITH AFFECTED DRINKING WATER:
SOURCE OF WATER SUPPLY:
ALTERNATE WATER SUPPLY AVAILABLE (If yes, what type?):
i
NUMBER OF PERSONS WITH POTENTIALLY AFFECTED WATER:
NUMBER OF PERSONS KNOWN AND/OR POTENTIALLY AFFECTED BY VAPORS:
VAPOR TREATMENT (provide detail, if any):
DEPTH TO GROUND WATER/METHOD TO DETERMINE:
SOIL PERMEABILITY (circle one): Low Medium High
SOIL CHARACTERISTICS:
DEPTH TO BEDROCK:
SITE CONDITIONS WHICH COULD AFFECT PLUME MIGRATION:
PRELIMINARY RECOMMENDATIONS FOR INVESTIGATIVE/REMEDIAL APPROACH:
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WORKSHEET 3 — EVALUATION OF ANTICIPATED SITE CONDITIONS
To determine if a proposed scope of work satisfactorily addresses specific site conditions, an
inspector may want to answer the following questions. Some questions addressed during the
early stages of a cleanup may need to be reexamined later.
INITIAL RESPONSE
1. What are the anticipated soil conditions? Is a sand and gravel layer present; if so how
thick?
2. What is the estimated Tpm'nim^T^ depth from ground surface to the water table? What
are the seasonal low elevations and possible tidal influences?
3. Do any man-made features exist which could act as conduits for contaminant
migration?
4. What are the unique site features (e.g., on-site or nearby streams) which might influ-
ence site conditions?
LIMITED SITE INVESTIGATION
5. Is any contaminated soil found in past borings? Where? How far from the water table?
What contaminants were identified?
6. Are any bedrock outcroppings located on or near the site?
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WORKSHEET 3 — EVALUATION OF ANTICIPATED SITE CONDITIONS
(Continued)
7. Do any borings show indications of encountering bedrock? If so, are any fractures or
joints identified which may provide conduits for contamination?
8. What is the hydraulic conductivity of the soils? (See Appendix B.) What is the antici-
pated time it will take for contaminants to reach the ground water?
9. Has a confining layer been identified? If so, is contamination expected to be present
below? Were past deep borings adequately sealed between strata?
10. What is the anticipated direction of groundwater flow?
11. What are the locations and depths of nearby and downgradient drinking water wells?
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WORKSHEET 4 — PREPARATION FOR FIELD OPERATIONS
Prior to initiating field work for a subsurface investigation, the following measures may be
taken by the owner/operator/contractor:
1. Obtain permission from property owners, preferably in writing.
2. Notify the appropriate utility companies or central notification
organization. (Record date and contact person).
3. Locate and mark the following lines: gas
telephone
sewer
power
water
oil
4. Check available site plans to identify the additional utility lines not
marked by the utility companies (e.g. connecting service lines
branching off from the main lines).
5. Review available information on site conditions (such as type of soil,
anticipated depth to ground water, and proximity to nearby surface
water bodies) as well as information on history of site and adjoining
properties as identified in Worksheets 1 & 2.
6. Sketch boring/excavation location plan. Select general locations and
depths for test pits or (at least three) test borings and/or observation
wells based on the available information. Check locations to verify
that overhead and underground obstructions are avoided. Typically,
at least one boring/well should be located upgradient.
7. Choose the appropriate sampling/excavation technique based on the
anticipated conditions at the selected locations. (See Exhibit 11 on
page 42 for Well Drilling Methods.) Test pits or trenches may be used
when visual observation of a continuous area is desired. However, test
pits have limited depth; for example, they typically can only extend a
few feet below the water table.
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WORKSHEET 4 — PREPARATION FOR FIELD OPERATIONS
(Continued)
8. Address the following miscellaneous issues:
a. Confirm the following with contractors: site location and
directions, meeting time, and necessary equipment (drilling
equipment request should include estimated quantities of rods,
augers, casing, well screen, grout, and lock boxes).
b. If decontamination is required, make provisions for steam-cleaning
equipment and collection and disposal of rinse water. Check with
the appropriate implementing authority on rinsewater disposal.
c. Confirm availability of drilling water if rotary drilling is to be used.
d. Develop health and safety information (including the locations of
the nearest hospitals) and maintain on the site.
9. Gather all the equipment and materials necessary for field inspection
identified on the attached Equipment Lost.
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EQUIPMENT LIST
In order to minimize errors and delays, prepared field personnel will typically be equipped with
the following items:
Field Notebook
Weighted tape (may also need chalk, paste, interface probe, and/or electric water level
reader)
Protective gloves
Clean sample containers
Labels
Waterproof markers
Cooler (with ice or dry ice)
Spray paint/stakes/flagging
Log sheets
Decontamination fluid
Paper towels
Camera and film
Bailers and cable and/or pump with tubing '
Plastic bags (e.g. for duplicate samples and contaminated equipment)
Key to protective casing or road box over well
Jackknife, large screwdriver, hammer, channel lock pliers
Directions to site, site plan, emergency telephone numbers
Hard hat and steel-toe boots
-------
REFERENCES
SOIL AND GROUNDWATER INVESTIGATIONS
Barcelona, M.J., J.P. Gibb and R.A. Miller. A Guide to the Selec-
tion of Materials for Monitoring Well Construction and Groundwa-
ter ffflmplinpr. ISWS Contract Report 327, Illinois State Water
Survey, Champaign, IL. 1983.
Driscoll, Fletcher G. Groundwater and Wells. Second Edition.
Johnson Division. 1986.
Everett, Lome G. Groundwater Monitoring. General Electric
Company, Technology Marketing Operation. 1980.
Freeze, R. Allan, and John A. Cherry. Groundwater. Prentice-
Hall, Inc. 1979.
Khanbilbardi, Reza M., and John Fillos. Groundwater Hydrology.
CPTlt91T>ination. and Remediation. 1986.
Shepard, W.D., "Practical Geohydrological Aspects of Groundwater
Contamination."
U.S. Environmental Protection Agency, Environmental Monitoring
Systems Laboratory. Monitoring in the Vadose Zone: A Review of
Technical Elements and Methods. Interagency Energy-Environ-
ment Research and Development Program Report. EPA-600/7-80-
134. June 1980.
U.S. Geological Survey, Heath, Ralph C. Basic Ground-water
Hydrology. Water-Supply Paper 2220, United States Government
Printing Office. 1983.
REMEDIATION
American Petroleum Institute. Cleaning Petroleytn
Tanks. API Bulletin 2015. 3rd Edition, September 1985.
American Petroleum Institute. Management of Underground
Petrolfiym fiforage Systems at Marketing and Distribution
Facilities. API Recommended Practice 1635. 3rd Edition,
November 1987.
-------
REFERENCES
REMEDIATION (CONTINUED)
American Petroleum Institute. Removal and Disposal of Used
Underground Petmlenm Storage Tanks. API Bulletin 1604. Rec-
ommended Practice, 2nd Edition, 1987.
American Petroleum Institute. Underground S/p?ll ClfianuP
Manual. API Bulletin 1628.1st Edition, June 1980.
Roy F. Weston, Inc., and the University of Massachusetts. Pre-
pared for Electric Power Research Institute and Utility Solid
Waste Activities Group. Remedial Technologies for Leaking Under-
ground Storage Tanks. July 1987.
U.S. Environmental Protection Agency, Hazardous Waste Engi-
neering Research Laboratory, Office of Solid Waste and Emer-
gency Response. Underground Storage Tank Corrective Action
Technologies. EPA/625/6-87-015. January 1987.
U.S. Environmental Protection Agency, Office of Underground
Storage Tanks. Cleanup of Releases from Petroleum USTft:
Selected Technologies. EPA/530/UST-88/001. April 1988. Avail-
able from Superintendent of Documents, Government Printing
Office, Washington, B.C., 20402, Stock No. 055-000-00272-0,
(202)783-3238.
U.S. Environmental Protection Agency, Office of Underground
Storage Tanks. "Tank Closure Without Tears: An Inspector's
Safety Guide." 1988. (Video) See "Video Ordering Information"
at end of the References.
LEAK DETECTION
American Petroleum Institute. Cathodic Protection of Under-
ground Petroleum ^tnrage Tanks and Piping Systems. API
Bulletin 1632. 2nd Edition, 1987.
American Petroleum Institute. Observation Wells as Release
Monitoring Techniques. July 1986.
Geonomics, Inc. Soil Vapor Monitoring for Fuel Leak Detection.
-------
REFERENCES
LEAK DETECTION (CONTINUED)
Maresca, Joseph W. Jr., and Monique Seibel, Vista Research Inc.
Volumetric Tank Testing. Prepared for Carol L. Grove, Center for
Environmental Research Information, Office of Research and
Development, U.S. Environmental Protection Agency. November
14,1988.
Niaki, 8., and John A. Broscious, IT Corporation. Prepared for
John S. Farlow, Releases Control Branch, Hazardous Waste
Engineering Research Laboratory, Office of Research and Develop-
ment, U.S. Environmental Protection Agency. Draft. Under-
ground Tank Leak Detection Methods: A State-of-the-Art Review.
U.S. Environmental Protection Agency Environmental Monitoring
Systems Laboratory, Office of Research and Development, Survey
of Vendors of External PetroHgyrn Leak Monitoring Devices for Use
With Underground Storage Tanks. EPA/600/4-87/016. 1987.
STATE MANUALS
New York State Department of Environmental Conservation,
Division of Water, Bureau of Water Resources. Recommended
Practices for Underground Storage of Ppfrroleym May 1984.
State of California Leaking Underground Fuel Tank Task Force.
Leaking1 Underground Fuel Tank Field Manual: Guidelines for Site
Assessment. Cleanup, and Underground Storage Tank Closure.
December 1987.
VIDEO ORDERING INFORMATION
"Tank Closure Without Tears: An Inspector's Safety Guide"
- Focuses on the problems of explosive vapors, safe tank removal
and closure (30 minutes).
Purchase: Video and companion booklet: $25.00 prepaid
Booklet only: $5.00 prepaid
Order from: New England Interstate Water
Pollution Control Commission
Attn: VIDEOS
85 Merrimac Street
Boston, MA 02114
-------
REFERENCES
VIDEO ORDERING INFORMATION (CONTINUED)
Loan:
Video and companion booklet: $5.00 prepaid
Order from: New England Regional
Wastewater Institute
2 Fort Road
South Portland, ME 04106
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INDEX
Active vapor control 16,73-77
Adsorptive capacity 23,25,35, 73, 76
Alternative water supplies 17,18, 65, 66
Aquifer (see ground water)
characteristics 23, 55, 56
restoration 17,18
shallow,deep 52
Analytical procedures 39-41
Asphalt batching (see soil
remediation)
Barriers 61,62,64
Bentonite seals 53-55
Benzene analysis 40,41
Biodegradation 30,31
Boring log 44,45
Cleanup criteria (see
regulatory requirements)
Combustible gas indicator (CGI) 6,9
Community water supplies 16-18, 65, 66
Confined spaces 6, 7,16
Contaminant migration 7, 8,13,15, 23, 25,
44, 61, 79-82
Darcy's Law 79, 81
Detection meters 6, 7,9
Draeger tubes 9
Drains 62,63
Drinking water supplies
(see community and private)
Elevation survey 55, 56
Enhanced volatilization 30, 31,46,47
Explosimeters (see CGIs)
Excavations 30, 83, 84
Filter pack 52-54
Fire and safety hazards 6, 7,9
Flame ionization detector (FID)
9
Floating (free) product
containment/recovery
(from surface waters and
subsurface collection points) 14,18
measurement 13, 57, 58
recovery from ground water 61, 62
Ground water
direction of flow 52
elevation 55, 56, 57
gradient 52, 79
sampling 56-60
use 16,17, 65
velocity 56,81
Grout
as barriers 62
in boreholes 53-55
Hydrocarbon vapors 6, 7, 9,16, 28, 36-41
Incineration 46, 47
Inventory records 10-12
Laboratory analyses
general use 39
quality control 39, 60
types of analyses 40, 41
Lead analysis 41
Man-made structures 7,11
Monitoring well
design 52-54
development 54
floating product in 57, 58
installation 52-54
location 52,54, 55
materials 52-54
purging 57, 59, 60
survey 55
-------
Oxygen indicator 6,9
Unsaturated flow 35, 79
Passive vapor control 16, 71-73
Permeability 23-25, 35, 75, 82
Photoionization detector (PID) 7, 9
Piezometers 55
Porosity 35,55,56
Private water supply wells 16-18
Purging
disposal of water 60
pumps 57-59
Vapor control 6,16, 71-77
Ventilation 7,16
Volatile organic compounds (see hydrocarbon
vapors)
Well drilling methods 38,42
Recovery wells 61-63
Regulatory requirements
drinking water 17, 61
reporting 19,31,48,66
soil remediation 46, 47
tank removal, repair, closure 28,83-85
Remediation (see
soil remediation)
Sampling (see ground water, soil
sampling)
Sheet piles 62
Sinker constituents 52
Slurry walls 62
Soil boring 38,42
Soil gas survey 28,29,36,37
Soil remediation
asphalt batching 30,31,46,47
biodegradation 30, 31,46,47
enhanced volatilization 30, 31,46,47
excavation/removal 30, 31,46,47
incineration 46,47
Soil sampling 28,29, 36, 38,43,44
Soil screening 28,29,36,37,38
Split-spoon sampler 43, 44
Surface water 15,18, 61
Tank
closure 28,83-85
repair 85
tightness testing 13, 85
Test pits 38,43
Total petroleum hydrocarbon analysis 17,40
Transport pathway 79-82
Trenches 61-63
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PURPOSE, CONTENT, AND
ORGANIZATION
-------
INITIAL RESPONSE
-------
LIMITED SITE INVESTIGATION
-------
SCENARIO A
-------
SCENARIO B
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SCENARIO C
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APPENDICES
-------
WORKSHEETS
-------
REFERENCES
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INDEX
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