United States
Environmental Protection
Agency
Office of Solid Waste and
Emergency Response
Washington DC 20460
EPAy540/P-91/006
January 1991
Compendium of ERT
Soil Sampling and
Surface Geophsics
Procedures
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EPA/540/P-91/006
OSWER Directive 9360.4-02
January 1991
COMPENDIUM OF ERT SOIL SAMPLING AND
SURFACE GEOPHYSICS PROCEDURES
Sampling Equipment Decontamination
Soil Sampling
Soil Gas Sampling
General Surface Geophysics
Interim Final
Environmental Response Team
Emergency Response Division
Office of Emergency and Remedial Response
U.S. Environmental Protection Agency
Washington, DC 20460
Printed on Recycled Paper
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Notice
This document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved
for publication. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
The policies and procedures established in this document are intended solely for the guidance of government
personnel for use in the Superfund Removal Program. They are not intended, and cannot be relied upon, to
create any rights, substantive or procedural, enforceable by any party in litigation with the United States. The
Agency reserves the right to act at variance with these policies and procedures and to change them at any time
without public notice.
Depending on circumstances and needs, it may not be possible or appropriate to follow these procedures exactly
in all situations due to site conditions, equipment limitations, and limitations of the standard procedures.
Whenever these procedures cannot be followed as written, they may be used as general guidance with any and
all modifications fully documented in either QA Plans, Sampling Plans, or final reports of results.
Each Standard Operating Procedure in this compendium contains a discussion on quality assurance/quality
control (QA/QC). For more information on QA/QC objectives and requirements, refer to the Quality
Assurance/Quality Control Guidance for Removal Activities, OSWER directive 9360.4-01, EPA/540/G-90/004.
Questions, comments, and recommendations are welcomed regarding the Compendium of ERT Soil Sampling
and Surface Geophysics Procedures. Send remarks to:
Mr. William A. Coakley
Removal Program QA Coordinator
U.S. EPA - ERT
Raritan Depot - Building 18, MS-101
2890 Woodbridge Avenue
Edison, NJ 08837-3679
For additional copies of the Compendium of ERT Soil Sampling and Surface Geophysics Procedures, please
contact:
National Technical Information Service (NTIS)
U.S. Department of Commerce
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4600
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Table of Contents
1.0 SAMPLING EQUIPMENT DECONTAMINATION: SOP #2006
1.1 Scope and Application 1
1.2 Method Summary 1
1.3 Sample Preservation, Containers, Handling, and Storage 1
1.4 Interferences and Potential Problems 1
1.5 Equipment/Apparatus 1
1.6 Reagents 2
1.7 Procedures 2
1.7.1 Decontamination Methods 2
1.7.2 Field Sampling Equipment Cleaning Procedures 3
1.8 Calculations 3
1.9 Quality Assurance/Quality Control 3
1.10 Data Validation 4
1.11 Health and Safety 4
2.0 SOIL SAMPLING: SOP #2012
2.1 Scope and Application 5
2.2 Method Summary 5
2.3 Sample Preservation, Containers, Handling, and Storage 5
2.4 Interferences and Potential Problems 5
2.5 Equipment/Apparatus 5
2.6 Reagents 5
2.7 Procedures 6
2.7.1 Preparation 6
2.7.2 Sample Collection 6
2.8 Calculations 9
2.9 Quality Assurance/Quality Control 9
2.10 Data Validation 9
2.11 Health and Safety 9
3.0 SOIL GAS SAMPLING: SOP #2149
3.1 Scope and Application n
3.2 Method Summary U
3.3 Sample Preservation, Containers, Handling, and Storage 11
3.3.1 Tedlar Bag 11
3.3.2 TenaxTube 11
3.3.3 SUMMA Canister 11
111
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Section
3.4 Interferences and Potential Problem
3.41 HNU Measurements 12
3.4.2 Factors Affecting Organic Concentrations in Soil Gas
3.43 Soil Probe Clogging
3.4.4 Underground Utilities
3.5 Equipment/Apparatus
3.5JL Slam Bar Method
3.5.2 Power Hammer Method
3.6 Reagents
3.7 Procedures
3.71 Soil Gas Well Installation
3.7.2 Screening with Field Instruments
3.73 Tedlar Bag Sampling
3.7.4 Tenax Tube Sampling
3.7.5 SUMMA Canister Sampling
3.8 Calculations
3.8JL Field Screening Instruments
3.8.2 Photovac GC Analysis
3.9 Quality Assurance/Quality Control
3.91 Field Instrument Calibration
3.9.2 Gilian Model HFS113A Air Sampling Pump Calibration
3.9.3 Sample Probe Contamination
3.9.4 Sample Train Contamination
3.9.5 Field Blank
3.9.6 Trip Standard
3.9.7 Tedlar Bag Check
3.9.8 SUMMA Canister Check
3.9.9 Options
310 Data Validation
311 Health and Safety
12
12
12
12
12
12
13
13
13
13
14
14
14
16
16
16
16
16
16
16
16
16
16
16
17
17
17
17
17
IV
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4.0 SOIL SAMPLING AND SURFACE GEOPHYSICS: SOP #2159
41 Scope and Application 19
4.2 Method Summary 19
4.21 Magnetics 19
4.2.2 Electromagnetics 20
4.2.3 Electrical Resistivity 20
4.2.4 Seismic 21
4.2.5 Ground Penetrating Radar 22
4.3 Sample Preservation, Containers, Handling and Storage 23
4.4 Interferences and Potential Problems 23
4.5 Equipment/Apparatus 24
4.5.1 Magnetics 24
4.5.2 Electromagnetics 24
4.5.3 Electrical Resistivity 24
4.5.4 Seismic 24
4.5.5 Ground Penetrating Radar 24
4.6 Reagents 24
4.7 Procedures 24
4.8 Calculations 24
4.9 Quality Assurance/Quality Control 24
4.10 Data Validation 24
4.11 Health and Safety 24
APPENDIX A - Figures 25
APPENDIX B - HNU Field Protocol 29
REFERENCES 33
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List of Exhibits
Exhibit
Table 1:
Figure 1:
Figure 2:
Figure 3:
SOP
Recommended Solvent Rinse for Soluble Contaminants #2006
Sampling Augers #2012
Sampling Trier #2012
Sampling Train Schematic #2149
Page
4
26
27
28
VI
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Acknowledgments
Preparation of this document was directed by William A. Coakley, the Removal Program QA Coordinator of
the Environmental Response Team, Emergency Response Division. Additional support was provided under U.S.
EPA contract #68-03-3482 and U.S. EPA contract #68-WO-0036.
VII
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1.0 SAMPLING EQUIPMENT DECONTAMINATION: SOP #2006
1.1 SCOPE AND APPLICATION
This Standard Operating Procedure (SOP) describes
methods used for preventing or reducing cross-
contamination, and provides general guidelines for
sampling equipment decontamination procedures at
a hazardous waste site. Preventing or minimizing
cross-contamination in sampled media and in
samples is important for preventing the introduction
of error into sampling results and for protecting the
health and safety of site personnel.
Removing or neutralizing contaminants that have
accumulated on sampling equipment ensures
protection of personnel from permeating substances,
reduces or eliminates transfer of contaminants to
clean areas, prevents the mixing of incompatible
substances, and minimizes the likelihood of sample
cross-contamination.
1.2 METHOD SUMMARY
Contaminants can be physically removed from
equipment, or deactivated by sterilization or
disinfection. Gross contamination of equipment
requires physical decontamination, including
abrasive and non-abrasive methods. These include
the use of brushes, air and wet blasting, and high-
pressure water cleaning, followed by a wash/rinse
process using appropriate cleaning solutions. Use
of a solvent rinse is required when organic
contamination is present.
1.3 SAMPLE PRESERVATION,
CONTAINERS, HANDLING, AND
STORAGE
This section is not applicable to this SOP.
1.4 INTERFERENCES AND
POTENTIAL PROBLEMS
• The use of distilled/deionized water
commonly available from commercial
vendors may be acceptable for
decontamination of sampling equipment
provided that it has been verified by
laboratory analysis to be analyte free.
• An untreated potable water supply is not
an acceptable substitute for tap water. Tap
water may be used from any municipal
water treatment system for mixing of
decontamination solutions.
• Acids and solvents utilized in the
decontamination sequence pose the health
and safety risks of inhalation or skin
contact, and raise shipping concerns of
permeation or degradation.
• The site work plan must address disposal
of the spent decontamination solutions.
• Several procedures can be established to
minimize contact with waste and the
potential for contamination. For example:
Stress work practices that
minimize contact with hazardous
substances.
Use remote sampling, handling,
and container-opening techniques
when appropriate.
Cover monitoring and sampling
equipment with protective material
to minimize contamination.
Use disposable outer garments
and disposable sampling
equipment when appropriate.
1.5 EQUIPMENT/APPARATUS
appropriate personal protective clothing
non-phosphate detergent
selected solvents
long-handled brushes
drop cloths/plastic sheeting
trash container
paper towels
galvanized tubs or buckets
tap water
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distilled/deionized water
metal/plastic containers for storage and
disposal of contaminated wash solutions
pressurized sprayers for tap and
deionized/distilled water
sprayers for solvents
trash bags
aluminum foil
safety glasses or splash shield
emergency eyewash bottle
1.6 REAGENTS
There are no reagents used in this procedure aside
from the actual decontamination solutions and
solvents. In general, the following solvents are
utilized for decontamination purposes:
• 10% nitric acid(1)
• acetone (pesticide grade)(2)
• hexane (pesticide grade)(2)
• methanol
(1) Only if sample is to be analyzed for trace metals.
(2) Only if sample is to be analyzed for organics.
1.7 PROCEDURES
As part of the health and safety plan, develop and
set up a decontamination plan before any personnel
or equipment enter the areas of potential exposure.
The equipment decontamination plan should
include:
• the number, location, and layout of
decontamination stations
• which decontamination apparatus is needed
• the appropriate decontamination methods
• methods for disposal of contaminated
clothing, apparatus, and solutions
1.7.1 Decontamination Methods
All personnel, samples, and equipment leaving the
contaminated area of a site must be
decontaminated. Various decontamination methods
will either physically remove contaminants,
inactivate contaminants by disinfection or
sterilization, or do both.
In many cases, gross contamination can be removed
by physical means. The physical decontamination
techniques appropriate for equipment
decontamination can be grouped into two
categories: abrasive methods and non-abrasive
methods.
Abrasive Cleaning Methods
Abrasive cleaning methods work by rubbing and
wearing away the top layer of the surface containing
the contaminant. The following abrasive methods
are available:
• Mechanical: Mechanical cleaning methods
use brushes of metal or nylon. The
amount and type of contaminants removed
will vary with the hardness of bristles,
length of brushing time, and degree of
brush contact.
• Air Blasting: Air blasting is used for
cleaning large equipment, such as
bulldozers, drilling rigs or auger bits. The
equipment used in air blast cleaning
employs compressed air to force abrasive
material through a nozzle at high velocities.
The distance between the nozzle and the
surface cleaned, as well as the pressure of
air, the time of application, and the angle
at which the abrasive strikes the surface,
determines cleaning efficiency. Air blasting
has several disadvantages: it is unable to
control the amount of material removed, it
can aerate contaminants, and it generates
large amounts of waste.
• Wet Blasting: Wet blast cleaning, also
used to clean large equipment, involves use
of a suspended fine abrasive delivered by
compressed air to the contaminated area.
The amount of materials removed can be
carefully controlled by using very fine
abrasives. This method generates a large
amount of waste.
Non-Abrasive Cleaning Methods
Non-abrasive cleaning methods work by forcing the
contaminant off of a surface with pressure. In
general, less of the equipment surface is removed
using non-abrasive methods. The following non-
abrasive methods are available:
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• High-Pressure Water: This method
consists of a high-pressure pump, an
operator-controlled directional nozzle, and
a high pressure hose. Operating pressure
usually ranges from 340 to 680 atmospheres
(atm) which relates to flow rates of 20 to
140 liters per minute.
* Ultra-High-Pressure Water: This system
produces a pressurized water jet (from
1,000 to 4,000 atm). The ultra-high-
pressure spray removes tightly-adhered
surface film. The water velocity ranges
from 500 m/sec (1,000 atm) to 900 m/sec
(4,000 atm). Additives can enhance the
method. This method is not applicable for
hand-held sampling equipment.
Disinfection/Rinse Methods
• Disinfection: Disinfectants are a practical
means of inactivating infectious agents.
• Sterilization: Standard sterilization
methods involve heating the equipment.
Sterilization is impractical for large
equipment.
• Rinsing: Rinsing removes contaminants
through dilution, physical attraction, and
solubilization.
1.7.2 Field Sampling Equipment
Cleaning Procedures
Solvent rinses are not necessarily required when
organics are not a contaminant of concern and may
be eliminated from the sequence specified below.
Similarly, an acid rinse is not required if analysis
does not include inorganics.
1. Where applicable, follow physical removal
procedures specified in section L7J..
2. Wash equipment with a non-phosphate
detergent solution.
3. Rinse with tap water.
4. Rinse with distilled/deionized water.
5. Rinse with 10% nitric acid if the sample will be
analyzed for trace organics.
6. Rinse with distilled/deionized water.
7.
Use a solvent rinse (pesticide grade) if the
sample will be analyzed for organics.
8. Air dry the equipment completely.
9. Rinse again with distilled/deionized water.
Selection of the solvent for use in the
decontamination process is based on the
contaminants present at the site. Use of a solvent
is required when organic contamination is present
on-site. Typical solvents used for removal of
organic contaminants include acetone, hexane, or
water. An acid rinse step is required if metals are
present on-site. If a particular contaminant fraction
is not present at the site, the nine-step
decontamination procedure listed above may be
modified for site specificity. The decontamination
solvent used should not be among the contaminants
of concern at the site.
Table 1 lists solvent rinses which may be required
for elimination of particular chemicals. After each
solvent rinse, the equipment should be air dried and
rinsed with distilled/deionized water.
Sampling equipment that requires the use of plastic
tubing should be disassembled and the tubing
replaced with clean tubing, before commencement
of sampling and between sampling locations.
1.8 CALCULATIONS
This section is not applicable to this SOP.
1.9 QUALITY ASSURANCE/
QUALITY CONTROL
One type of quality control sample specific to the
field decontamination process is the rinsate blank.
The rinsate blank provides information on the
effectiveness of the decontamination process
employed in the field. When used in conjunction
with field blanks and trip blanks, a rinsate blank can
detect contamination during sample handling,
storage and sample transportation to the laboratory.
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Table 1: Recommended Solvent Rinse for Soluble Contaminants
SOLVENT
SOLUBLE CONTAMINANTS
Water
• Low-chain hydrocarbons
• Inorganic compounds
Salts
Some organic acids and other polar compounds
Dilute Acids
• Basic (caustic) compounds
• Amines
Hydrazines
Dilute Bases — for example, detergent
and soap
• Metals
• Acidic compounds
• Phenol
• Thiols
• Some nitro and sulfonic compounds
Organic Solvents1'5 - for example,
alcohols, ethers, ketones, aromatics,
straight-chain alkanes (e.g., hexane), and
common petroleum products (e.g., fuel,
oil, kerosene)
Nonpolar compounds (e.g., some organic compounds)
(1) - WARNING: Some organic solvents can permeate and/or degrade protective clothing.
A rinsate blank consists of a sample of analyte-free
(i.c, dcionized) water which is passed over and
through a field decontaminated sampling device and
placed in a clean sample container.
Rinsate blanks should be run for all parameters of
interest at a rate of 1 per 20 for each parameter,
even if samples are not shipped that day. Rinsate
blanks are not required if dedicated sampling
equipment is used.
1.10 DATA VALIDATION
This section is not applicable to this SOP.
1.11 HEALTH AND SAFETY
When working with potentially hazardous materials,
follow U.S. EPA, OSHA and specific health and
safely procedures.
Decontamination can pose hazards under certain
circumstances even though performed to protect
health and safety. Hazardous substances may be
incompatible with decontamination methods. For
example, the decontamination solution or solvent
may react with contaminants to produce heat,
explosion, or toxic products. Decontamination
methods may be incompatible with clothing or
equipment; some solvents can permeate or degrade
protective clothing. Also, decontamination solutions
and solvents may pose a direct health hazard to
workers through inhalation or skin contact, or if
they combust.
The decontamination solutions and solvents must be
determined to be compatible before use. Any
method that permeates, degrades, or damages
personal protective equipment should not be used.
If decontamination methods pose a direct health
hazard, measures should be taken to protect
personnel or the methods should be modified to
eliminate the hazard.
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2.0 SOIL SAMPLING: SOP #2012
2.1 SCOPE AND APPLICATION
The purpose of this Standard Operating Procedure
(SOP) is to describe the procedures for collecting
representative soil samples. Analysis of soil samples
may determine whether concentrations of specific
soil pollutants exceed established action levels, or if
the concentrations of soil pollutants present a risk
to public health, welfare, or the environment.
2.2 METHOD SUMMARY
Soil samples may be collected using a variety of
methods and equipment. The methods and
equipment used are dependent on the depth of the
desired sample, the type of sample required
(disturbed versus undisturbed), and the type of soil.
Near-surface soils may be easily sampled using a
spade, trowel, and scoop. Sampling at greater
depths may be performed using a hand auger, a
trier, a split-spoon, or, if required, a backhoe.
2.3 SAMPLE PRESERVATION,
CONTAINERS, HANDLING, AND
STORAGE
Chemical preservation of solids is not generally
recommended. Refrigeration to 4°C, supplemented
by a minimal holding time, is usually the best
approach.
2.4 INTERFERENCES AND
POTENTIAL PROBLEMS
There are two primary interferences or potential
problems associated with soil sampling. These
include cross-contamination of samples and
improper sample collection. Cross-contamination
problems can be eliminated or minimized through
the use of dedicated sampling equipment. If this is
not possible or practical, then decontamination of
sampling equipment is necessary. Improper sample
collection can involve using contaminated
equipment, disturbance of the matrix resulting in
compaction of the sample, or inadequate
homogenization of the samples where required,
resulting in variable, non-representative results.
2.5 EQUIPMENT/APPARATUS
sampling plan
maps/plot plan
safety equipment, as specified in the health
and safety plan
compass
tape measure
survey stakes or flags
camera and film
stainless steel, plastic, or other appropriate
homogenization bucket or bowl
1-quart mason jars w/Teflon liners
Ziploc plastic bags
logbook
labels
chain of custody forms and seals
field data sheets
cooler(s)
ice
decontamination supplies/equipment
canvas or plastic sheet
spade or shovel
spatula
scoop
plastic or stainless steel spoons
trowel
continuous flight (screw) auger
bucket auger
post hole auger
extension rods
T-handle
sampling trier
thin-wall tube sampler
Vehimeyer soil sampler outfit
- tubes
- points
- drive head
- drop hammer
- puller jack and grip
backhoe
2.6 REAGENTS
Reagents are not used for the preservation of soil
samples. Decontamination solutions are specified in
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ERT SOP #2006, Sampling Equipment
Decontamination.
2.7 PROCEDURES
2.7.1 Preparation
1. Determine the extent of the sampling effort, the
sampling methods to be employed, and which
equipment and supplies are required.
2. Obtain necessary sampling and monitoring
equipment.
3. Decontaminate or preclean equipment, and
ensure that it is in working order.
4. Prepare schedules, and coordinate with staff,
client, and regulatory agencies, if appropriate.
5. Perform a general site survey prior to site entry
in accordance with the site-specific health and
safety plan.
6. Use stakes, buoys, or flagging to identify and
mark all sampling locations. Consider specific
site factors, including extent and nature of
contaminant, when selecting sample location. If
required, the proposed locations may be
adjusted based on site access, property
boundaries, and surface obstructions. All
staked locations will be utility-cleared by the
property owner prior to soil sampling.
2.7.2 Sample Collection
Surface Soil Samples
Collect samples from near-surface soil with tools
such as spades, shovels, and scoops. Surface
material can be removed to the required depth with
this equipment, then a stainless steel or plastic
scoop can be used to collect the sample.
This method can be used in most soil types but is
limited to sampling near surface areas. Accurate,
representative samples can be collected with this
procedure depending on the care and precision
demonstrated by the sampling team member. The
use of a flat, pointed mason trowel to cut a block of
the desired soil can be helpful when undisturbed
profiles are required. A stainless steel scoop, lab
spoon, or plastic spoon will suffice in most other
applications. Avoid the use of devices plated with
chrome or other materials. Plating is particularly
common with garden implements such as potting
trowels.
Follow these procedures to collect surface soil
samples.
1. Carefully remove the top layer of soil or debris
to the desired sample depth with a pre-cleaned
spade.
2. Using a pre-cleaned, stainless steel scoop,
plastic spoon, or trowel, remove and discard a
thin layer of soil from the area which came in
contact with the spade.
3. If volatile organic analysis is to be performed,
transfer a portion of the sample directly into an
appropriate, labeled sample container(s) with a
stainless steel lab spoon, plastic lab spoon, or
equivalent and secure the cap(s) tightly. Place
the remainder of the sample into a stainless
steel, plastic, or other appropriate
homogenization container, and mix thoroughly
to obtain a homogenous sample representative
of the entire sampling interval. Then, either
place the sample into an appropriate, labeled
container(s) and secure the cap(s) tightly; or, if
composite samples are to be collected, place a
sample from another sampling interval into the
homogenization container and mix thoroughly.
When compositing is complete, place the
sample into appropriate, labeled container(s)
and secure the cap(s) tightly.
Sampling at Depth with Augers and Thin-
Wall Tube Samplers
This system consists of an auger, a series of
extensions, a "T" handle, and a thin-wall tube
sampler (Appendix A, Figure 1). The auger is used
to bore a hole to a desired sampling depth, and is
then withdrawn. The sample may be collected
directly from the auger. If a core sample is to be
collected, the auger tip is then replaced with a thin-
wall tube sampler. The system is then lowered
down the borehole, and driven into the soil at the
completion depth. The system is withdrawn and the
core collected from the thin-wall tube sampler.
Several types of augers are available. These
include: bucket, continuous flight (screw), and
pesthole augers. Bucket augers are better for direct
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sample recovery since they provide a large volume
of sample in a short time. When continuous flight
augers are used, the sample can be collected
directly from the flights, which are usually at 5-feet
intervals. The continuous flight augers are
satisfactory for use when a composite of the
complete soil column is desired. Pesthole augers
have limited utility for sample collection as they are
designed to cut through fibrous, rooted, swampy
soil.
Follow these procedures for collecting soil samples
with the auger and a thin-wall tube sampler.
1. Attach the auger bit to a drill rod extension,
and attach the "T" handle to the drill rod.
2. Clear the area to be sampled of any surface
debris (e.g., twigs, rocks, litter). It may be
advisable to remove the first 3 to 6 inches of
surface soil for an area approximately 6 inches
in radius around the drilling location.
3. Begin augering, periodically removing and
depositing accumulated soils onto a plastic
sheet spread near the hole. This prevents
accidental brushing of loose material back down
the borehole when removing the auger or
adding drill rods. It also facilitates refilling the
hole, and avoids possible contamination of the
surrounding area.
4. After reaching the desired depth, slowly and
carefully remove the auger from boring. When
sampling directly from the auger, collect sample
after the auger is removed from boring and
proceed to Step 10.
5. Remove auger tip from drill rods and replace
with a pre-cleaned thin-wall tube sampler.
Install proper cutting tip.
6. Carefully lower the tube sampler down the
borehole. Gradually force the tube sampler
into the soil. Care should be taken to avoid
scraping the borehole sides. Avoid hammering
the drill rods to facilitate coring as the
vibrations may cause the boring walls to
collapse.
7. Remove the tube sampler, and unscrew the drill
rods.
8. Remove the cutting tip and the core from the
device.
9. Discard the top of the core (approximately 1
inch), as this represents material collected
before penetration of the layer of concern.
Place the remaining core into the appropriate
labeled sample container(s). Sample
homogenization is not required.
10. If volatile organic analysis is to be performed,
transfer a portion of the sample directly into an
appropriate, labeled sample containers) with a
stainless steel lab spoon, plastic lab spoon, or
equivalent and secure the cap(s) tightly. Place
the remainder of the sample into a stainless
steel, plastic, or other appropriate
homogenization container, and mix thoroughly
to obtain a homogenous sample representative
of the entire sampling interval. Then, either
place the sample into an appropriate, labeled
container(s) and secure the cap(s) tightly; or, if
composite samples are to be collected, place a
sample from another sampling interval into the
homogenization container and mix thoroughly.
When compositing is complete, place the
sample into the appropriate, labeled
container(s) and secure the cap(s) tightly.
11. If another sample is to be collected in the same
hole, but at a greater depth, reattach the auger
bit to the drill and assembly, and follow steps
3 through 11, making sure to decontaminate
the auger and tube sampler between samples.
12. Abandon the hole according to applicable state
regulations. Generally, shallow holes can
simply be backfilled with the removed soil
material.
Sampling at Depth with a Trier
The system consists of a trier, and a "T" handle.
The auger is driven into the soil to be sampled and
used to extract a core sample from the appropriate
depth.
Follow these procedures to collect soil samples with
a sampling trier.
1. Insert the trier (Appendix A, Figure 2) into the
material to be sampled at a 0° to 45° angle
from horizontal. This orientation minimizes
the spillage of sample.
2. Rotate the trier once or twice to cut a core of
material.
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3. Slowly withdraw the trier, making sure that the
slot is faring upward.
4. If volatile organic analysis is to be performed,
transfer a portion of the sample directly into an
appropriate, labeled sample containers) with a
stainless steel lab spoon, plastic lab spoon, or
equivalent and secure the cap(s) tightly. Place
the remainder of the sample into a stainless
steel, plastic, or other appropriate
homogenization container, and mix thoroughly
to obtain a homogenous sample representative
of the entire sampling interval. Then, either
place the sample into an appropriate, labeled
container^) and secure the cap(s) tightly; or, if
composite samples are to be collected, place a
sample from another sampling interval into the
homogenization container and mix thoroughly.
When compositing is complete, place the
sample into an appropriate, labeled container(s)
and secure the cap(s) tightly.
Sampling at Depth with a Split Spoon
(Barrel) Sampler
The procedure for split spoon sampling describes
the collection and extraction of undisturbed soil
cores of 18 or 24 inches in length. A series of
consecutive cores may be extracted with a split
spoon sampler to give a complete soil column
profile, or an auger may be used to drill down to
the desired depth for sampling. The split spoon is
then driven to its sampling depth through the
bottom of the augured hole and the core extracted.
When split tube sampling is performed to gain
geologic information, all work should be performed
in accordance with ASTM D 1586-67 (reapproved
1974).
Follow these procedures for collecting soil samples
with a split spoon.
1. Assemble the sampler by aligning both sides of
the barrel and then screwing the bit onto the
bottom and the heavier head piece onto the
top.
2. Place the sampler in a perpendicular position
on the sample material.
3. Using a sledge hammer or well ring, if
available, drive the tube. Do not drive past the
bottom of the head piece or compression of the
sample will result.
4. Record in the site logbook or on field data
sheets the length of the tube used to penetrate
the material being sampled, and the number of
blows required to obtain this depth.
5. Withdraw the sampler, and open by unscrewing
the bit and head and splitting the barrel. If a
split sample is desired, a cleaned, stainless steel
knife should be used to divide the tube contents
in hall', longitudinally. This sampler is typically
available in diameters of 2 and 3 1/2 niches.
However, in order to obtain the required
sample volume, use of a larger barrel may be
required.
6. Without disturbing the core, transfer it to an
appropriate labeled sample containers) and
seal tightly.
Test Pit/Trench Excavation
These relatively large excavations are used to
remove sections of soil, when detailed examination
of soil characteristics (horizontal structure, color,
etc.) are required. It is the least cost effective
sampling method due to the relatively high cost of
backhoe operation.
Follow these procedures for collecting soil samples
from test pit/trench excavations.
1. Prior to any excavation with a backhoe, it is
important to ensure that all sampling locations
are clear of utility lines and poles (subsurface
as well as above surface).
2. Using the backhoe, dig a trench to
approximately 3 feet in width and
approximately 1 foot below the cleared
sampling location. Place removed or excavated
soils on plastic sheets. Trenches greater than
5 feet deep must be sloped or protected by a
shoring system, as required by OSHA
regulations.
3. Use a shovel to remove a 1- to 2-inch layer of
soil from the vertical face of the pit where
sampling is to be done.
4. Take samples using a trowel, scoop, or coring
device at the desired intervals. Be sure to
scrape the vertical face at the point of sampling
-------
to remove any soil that may have fallen from
above, and to expose fresh soil for sampling. In
many instances, samples can be collected
directly from the backhoe bucket.
5. If volatile organic analysis is to be performed,
transfer a portion of the sample directly into an
appropriate, labeled sample container(s) with a
stainless steel lab spoon, plastic lab spoon, or
equivalent and secure the cap(s) tightly. Place
the remainder of the sample into a stainless
steel, plastic, or other appropriate
homogenization container, and mix thoroughly
to obtain a homogenous sample representative
of the entire sampling interval. Then, either
place the sample into an appropriate, labeled
container(s) and secure the cap(s) tightly; or, if
composite samples are to be collected, place a
sample from another sampling interval into the
homogenization container and mix thoroughly.
When compositing is complete, place the
sample into appropriate, labeled container(s)
and secure the cap(s) tightly.
6. Abandon the pit or excavation according to
applicable state regulations. Generally, shallow
excavations can simply be backfilled with the
removed soil material.
2.8 CALCULATIONS
This section is not applicable to this SOP.
2.9 QUALITY ASSURANCE/
QUALITY CONTROL
There are no specific quality assurance activities
which apply to the implementation of these
procedures. However, the following QA procedures
apply:
• All data must be documented on field data
sheets or within site logbooks.
• All instrumentation must be operated in
accordance with operating instructions as
supplied by the manufacturer, unless
otherwise specified in the work plan.
Equipment checkout and calibration
activities must occur prior to
sampling/operation, and they must be
documented.
2.10 DATA VALIDATION
This section is not applicable to this SOP.
2.11 HEALTH AND SAFETY
When working with potentially hazardous materials,
follow U.S. EPA, OSHA, and specific health and
safety procedures.
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3.0 SOIL GAS SAMPLING: SOP #2149
3.1 SCOPE AND APPLICATION
Soil gas monitoring provides a quick means of waste
site evaluation. Using this method, underground
contamination can be identified, and the source,
extent, and movement of the pollutants can be
traced.
This Standard Operating Procedure (SOP) outlines
the methods used by EPA/ERT in installing soil gas
wells'; measuring organic levels in the soil gas using
an HNU PI 101 Portable Photoionization Analyzer
and/or other air monitoring devices; and sampling
the soil gas using Tedlar bags, Tenax sorbent tubes,
and SUMMA canisters.
3.2 METHOD SUMMARY
A 3/8-inch diameter hole is driven into the ground
to a depth of 4 to 5 feet using a commercially
available "slam bar". (Soil gas can also be sampled
at other depths by the use of a longer bar or bar
attachments.) A 1/4-inch O.D. stainless steel probe
is inserted into the hole. The hole is then sealed at
the top around the probe using modeling clay. The
gas contained in the interstitial spaces of the soil is
sampled by pulling the sample through the probe
using an air sampling pump. The sample may be
stored in Tedlar bags, drawn through sorbent
cartridges, or analyzed directly using a direct
reading instrument.
The air sampling pump is not used for SUMMA
canister sampling of soil gas. Sampling is achieved
by soil gas equilibration with the evacuated
SUMMA canister. Other field air monitoring
devices, such as the combustible gas indicator (MSA
CGI/02 Meter, Model 260) and the organic vapor
analyzer (Foxboro OVA, Model 128), can also be
used depending on specific site conditions.
Measurement of soil temperature using a
temperature probe may also be desirable. Bagged
samples are usually analyzed in a field laboratory
using a portable Photovac GC.
Power driven sampling probes may be utilized when
soil conditions make sampling by hand unfeasible
(i.e., frozen ground, very dense clays, pavement,
etc.). Commercially available soil gas sampling
probes (hollow, 1/2-inch O.D. steel probes) can be
driven to the desired depth using a power hammer
(e.g., Bosch Demolition Hammer). Samples can be
drawn through the probe itself, or through Teflon
tubing inserted through the probe and attached to
the probe point. Samples are collected and
analyzed as described above.
3.3 SAMPLE PRESERVATION,
CONTAINERS, HANDLING, AND
STORAGE
3.3.1 Tedlar Bag
Soil gas samples are generally contained in 1-L
Tedlar bags. Bagged samples are best stored in
coolers to protect the bags from any damage that
may occur in the field or in transit. In addition,
coolers ensure the integrity of the samples by
keeping them at a cool temperature and out of
direct sunlight. Samples should be analyzed as soon
as possible, preferably within 24 to 48 hours.
3.3.2 Tenax Tube
Bagged samples can also be drawn into Tenax or
other sorbent tubes to undergo lab GC/MS analysis.
If Tenax tubes are to be utilized, special care must
be taken to avoid contamination. Handling of the
tubes should be kept to a minimum, and samplers
must wear nylon or other lint-free gloves. After
sampling, each tube should be stored in a clean,
sealed culture tube; the ends packed with clean
glass wool to protect the sorbent tube from
breakage. The culture tubes should be kept cool
and wrapped in aluminum foil to prevent any
photodegradation of samples (see Section 3.7.4.).
3.3.3 SUMMA Canister
The SUMMA canisters used for soil gas sampling
have a 6-L sample capacity and are certified clean
by GC/MS analysis before being utilized in the
field. After sampling is completed, they are stored
and shipped in travel cases.
11
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3.4 INTERFERENCES AND
POTENTIAL PROBLEMS
3.4.1 HNU Measurements
A number of factors can affect the response of the
HNU PI 101. High humidity can cause lamp
fogging and decreased sensitivity. This can be
significant when soil moisture levels are high, or
when a soil gas well is actually in groundwater.
High concentrations of methane can cause a
downscale deflection of the meter. High and low
temperature, electrical fields, FM radio
transmission, and naturally occurring compounds,
such as terpenes in wooded areas, will also affect
instrument response.
Other field screening instruments can be affected by
interferences. Consult the manufacturers' manuals.
3.4.2 Factors Affecting Organic
Concentrations in Soil Gas
Concentrations in soil gas are affected by
dissolution, adsorption, and partitioning.
Partitioning refers to the ratio of component found
in a saturated vapor above an aqueous solution to
the amount in the solution; this can, in theory, be
calculated using the Henry's Law constants.
Contaminants can also be adsorbed onto inorganic
soil components or "dissolved" in organic
components. These factors can result in a lowering
of the partitioning coefficient.
Soil "tightness" or amount of void space hi the soil
matrix, will affect the rate of recharging of gas into
the soil gas well.
Existence of a high, or perched, water table, or of
an impermeable underlying layer (such as a clay
lens or layer of buried slag) may interfere with
sampling of the soil gas. Knowledge of site geology
is useful in such situations, and can prevent
inaccurate sampling.
3.4.3 Soil Probe Clogging
A common problem with this sampling method is
soil probe clogging. A clogged probe can be
identified by using an in-line vacuum gauge or by
listening for the sound of the pump laboring. This
problem can usually be eliminated by using a wire
cable to clear the probe (see procedure #3 in
Section 3.7.1).
3.4.4 Underground Utilities
Prior to selecting sample locations, an underground
utility search is recommended. The local utility
companies can be contacted and requested to mark
the locations of their underground lines. Sampling
plans can then be drawn up accordingly. Each
sample location should also be screened with a
metal detector or magnetometer to verify that no
underground pipes or drums exist.
3.5 EQUIPMENT/APPARATUS
3.5.1 Slam Bar Method
slam bar (one per sampling team)
soil gas probes, stainless steel tubing, 1/4-
inch O.D., 5 foot length
flexible wire or cable used for clearing the
tubing during insertion into the well
"quick connect" fittings to connect sampling
probe tubing, monitoring instruments, and
Gilian pumps to appropriate fittings on
vacuum box
modeling clay
va.cuum box for drawing a vacuum around
Tedlar bag for sample collection (one per
sampling team)
Gilian pump Model HFS113A adjusted to
approximately 3.0 L/min (one to two per
sampling team)
1/4-inch Teflon tubing, 2 to 3 foot lengths,
for replacement of contaminated sample
line
Tedlar bags, 1 liter, at least one bag per
sample point
soil gas sampling labels, field data sheets,
logbook, etc.
HNU Model PI 101, or other field air
monitoring devices, (one per sampling
team)
ice chest, for carrying equipment and for
protection of samples (two per sampling
team)
metal detector or magnetometer, for
detecting underground utilities/
pipes/drums (one per sampling team)
Photovac GC, for field-lab analysis of
bagged samples
SUMMA canisters (plus then* shipping
cases) for sample, storage and
transportation
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3.5.2 Power Hammer Method
• Bosch demolition hammer
• 1/2-inch O.D. steel probes, extensions, and
points
• dedicated aluminum sampling points
• Teflon tubing, 1/4-inch O.D.
• "quick connect" fittings to connect sampling
probe tubing, monitoring instruments, and
Gilian pumps to appropriate fittings on
vacuum box
• modeling clay
• vacuum box for drawing a vacuum around
Tedlar bag for sample collection (one per
sampling team)
• Gilian pump Model HFS113A adjusted to
approximately 3.0 L/min (one to two per
sampling team)
• 1/4-inch Teflon tubing, 2 to 3 foot lengths,
for replacement of contaminated sample
line
• Tedlar bags, 1 liter, at least one bag per
sample point
• soil gas sampling labels, field data sheets,
logbook, etc.
• HNU Model PI 101, or other field air
monitoring devices, (one per sampling
team)
• ice chest, for carrying equipment and for
protection of samples (two per sampling
team)
• metal detector or magnetometer, for
detecting underground utilities/
pipes/drums (one per sampling team)
• Photovac GC, for field-lab analysis of
bagged samples
• SUMMA canisters (plus their shipping
cases) for sample, storage and
transportation
• generator with extension cords
• high lift jack assembly for removing probes
3.6 REAGENTS
• HNU Systems Inc. Calibration Gas for
HNU Model PI 101, and/or calibration gas
for other field air monitoring devices
• deionized organic-free water, for
decontamination
• methanol, HPLC grade, for
decontamination
• ultra-zero grade compressed air, for field
blanks
standard gas preparations for Photovac GC
calibration and Tedlar bag spikes
3.7 PROCEDURES
3.7.1 Soil Gas Well Installation
1. Initially, make a hole slightly deeper than the
desired depth. For sampling up to 5 feet, use
a 5-foot single piston slam bar. For deeper
depths, use a piston slam bar with threaded 4-
foot-long extensions. Other techniques can be
used, so long as holes are of narrow diameter
and no contamination is introduced.
2. After the hole is made, carefully withdraw the
slam bar to prevent collapse of the walls of the
hole. Then insert the soil gas probe.
3. It is necessary to prevent plugging of the probe,
especially for deeper holes. Place a metal wire
or cable, slightly longer than the probe, into the
probe prior to inserting into the hole. Insert
the probe to full depth, then pull it up 3 to 6
inches, then clear it by moving the cable up and
down. The cable is removed before sampling.
4. Seal the top of the sample hole at the surface
against ambient air infiltration by using
modeling clay molded around the probe at the
surface of the hole.
5. If conditions preclude hand installation of the
soil gas wells, the power driven system may be
employed. Use the generator-powered
demolition hammer to drive the probe to the
desired depth (up to 12 feet may be attained
with extensions). Pull the probe up 1 to 3
inches if the retractable point is used. No clay
is needed to seal the hole. After sampling,
retrieve the probe using the high lift jack
assembly.
6. If semi-permanent soil gas wells are required,
use the dedicated aluminum probe points.
Insert these points into the bottom of the
power-driven probe and attach it to the Teflon
tubing. Insert the probe as in step 5. When
the probe is removed, the point and Teflon
tube remain in the hole, which may be sealed
by backfilling with sand, bentonite, or soil.
13
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3.7.2 Screening with Field
Instruments
1. The well volume must be evacuated prior to
sampling. Connect the Gilian pump, adjusted
to 3.0 L/min, to the sample probe using a
section of Teflon tubing as a connector. Turn
the pump on, and a vacuum is pulled through
the probe for approximately 15 seconds. A
longer tune is required for sample wells of
greater depths.
2. After evacuation, connect the monitoring
instruments) to the probe using a Teflon
connector. When the reading is stable, or
peaks, record the reading. For detailed
procedures on HNU field protocol, see
appendix B, and refer to the manufacturer's
instructions.
3. Some readings may be above or below the
range set on the field instruments. The range
may be reset, or the response recorded as a
figure greater than or less than the range.
Consider the recharge rate of the well with soil
gas when sampling at a different range setting.
3.7.3 Tedlar Bag Sampling
1. Follow step 1 in section 3.7.2 to evacuate well
volume. If air monitoring instrument screening
was performed prior to sampling, evacuation is
not necessary.
2. Use the vacuum box and sampling train (Figure
3 in Appendix A) to take the sample. The
sampling train is designed to minimize the
introduction of contaminants and losses due to
adsorption. All wetted parts are either Teflon
or stainless steel. The vacuum is drawn
indirectly to avoid contamination from sample
pumps.
3. Place the Tedlar bag inside the vacuum box,
and attach it to the sampling port. Attach the
sample probe to the sampling port via Teflon
tubing and a "quick connect" fitting.
4. Draw a vacuum around the outside of the bag,
using a Gilian pump connected to the vacuum
box evacuation port, via Tygon tubing and a
"quick connect" fitting. The vacuum causes the
bag to inflate, drawing the sample.
5. Break, the vacuum by removing the Tygon line
from the pump. Remove the bagged sample
from the box and close valve. Label bag,
record data on data sheets or in logbooks.
Record the date, time, sample location ID, and
the HNU, or other instrument reading(s) on
sample bag label.
CAUTION: Labels should not be pasted directly
onto the bags, nor should bags be labeled directly
using a marker or pen. Inks and adhesive may
diffuse through the bag material, contaminating the
sample. Place labels on the edge of the bags, or tie
the labels to the metal eyelets provided on the bags.
Markers with inks containing volatile organics (i.e.,
permanent: ink markers) should not be used.
3.7.4 Tenax Tube Sampling
Samples collected in Tedlar bags may be sorbed
onto Tenax tubes for further analysis by GC/MS.
Additional Apparatus
• Syringe with a luer-lock tip capable of
drawing a soil gas or air sample from a
Tedlar bag onto a Tenax/CMS sorbent
tube. The syringe capacity is dependent
upon the volume of sample being drawn
onto the sorbent tube.
• Adapters for fitting the sorbent tube
between the Tedlar bag and the sampling
syringe. The adapter attaching the Tedlar
bag to the sorbent tube consists of a
reducing union (1/4-inch to 1/16-inch O.D.
~ Swagelok cat. # SS-400-6-ILV or
equivalent) with a length of 1/4-inch O.D.
Teflon tubing replacing the nut on the 1/6-
inch (Tedlar bag) side. A 1/4-inch I.D.
silicone O-ring replaces the ferrules in the
nut on the 1/4-inch (sorbent tube) side of
the union.
The adapter attaching the sampling syringe
to the sorbent tube consists of a reducing
union (1/4-inch to 1/16-inch O.D. —
Swagelok Cat. # SS-400-6-ILV or
equivalent) with a 1/4-inch I.D. silicone
O-ring replacing the ferrules in the nut on
the 1/4-inch (sorbent tube) side and the
needle of a luer-lock syringe needle
inserted into the 1/16-inch side (held in
place with a 1/16-inch ferrule). The
14
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luer-lock end of the needle can be attached
to the sampling syringe. It is useful to have
a luer-lock on/off valve situated between
the syringe and the needle.
• Two-stage glass sampling cartridge (1/4-
inch O.D. x 1/8-inch I.D. x 5 1/8 inch)
contained in a flame-sealed tube
(manufactured by Supelco Custom
Tenax/Spherocarb Tubes or equivalent)
containing two sorbent sections retained by
glass wool:
Front section: 150 mg of Tenax-GC
Back section: 150 mg of CMS
(Carbonized Molecular Sieve)
Sorbent tubes may also be prepared in the
lab and stored in either Teflon-capped
culture tubes or stainless steel tube
containers. Sorbent tubes stored in this
manner should not be kept more than 2
weeks without reconditioning. (See SOP
#2052 for Tenax/CMS sorbent tube
preparation).
• Teflon-capped culture tubes or stainless
steel tube containers for sorbent tube
storage. These containers should be
conditioned by baking at 120°C for at least
2 hours. The culture tubes should contain
a glass wool plug to prevent sorbent tube
breakage during transport. Reconditioning
of the containers should occur between
usage or after extended periods of disuse
(i.e., 2 weeks or more).
• Nylon gloves or lint-free cloth. (Hewlett
Packard Part # 8650-0030 or equivalent.)
Sample Collection
1. Handle sorbent tubes with care, using nylon
gloves (or other lint-free material) to avoid
contamination.
2. Immediately before sampling, break one end of
the sealed tube and remove the Tenax
cartridge. For in-house prepared tubes, remove
cartridge from its container.
3. Connect the valve on the Tedlar bag to the
sorbent tube adapter. Connect the sorbent tube
to the sorbent tube adapter with the Tenax
4.
(white granular) side of the tube facing the
Tedlar bag.
Connect the sampling syringe assembly to the
CMS (black) side of the sorbent tube. Fittings
on the adapters should be very tight.
5. Open the valve on the Tedlar bag.
6. Open the on/off valve of the sampling syringe.
7. Draw a predetermined volume of sample onto
the sorbent tube. (This may require closing the
syringe valve, emptying the syringe and then
repeating the procedure, depending upon the
syringe capacity and volume of sample
required.)
8. After sampling, remove the tube from the
sampling train with gloves or a clean cloth. Do
not label or write on the Tenax/CMS tube.
9. Place the sorbent tube hi a conditioned
stainless steel tube holder or culture tube.
Culture tube caps should be sealed with Teflon
tape.
Sample Labeling
Each sample tube container (not tube) must be
labeled with the site name, sample station number,
sample date, and sample volume.
Chain of custody forms must accompany all samples
to the laboratory.
Quality Assurance
Before field use, a QA check should be performed
on each batch of sorbent tubes by analyzing a tube
with thermal desorption/cryogenic trapping
GC/MS.
At least one blank sample must be submitted with
each set of samples collected at a site. This trip
blank must be treated the same as the sample tubes
except no sample will be drawn through the tube.
Sample tubes should be stored out of UV light (i.e.,
sunlight) and kept on ice until analysis.
Samples should be taken in duplicate, when
possible.
15
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3.7.5 SUMMA Canister Sampling
1. Follow item 1 in step 3.7.2 to evacuate well
volume. If HNU analysis was performed prior
to taking a sample, evacuation is not necessary.
2. Attach a certified clean, evacuated 6-L
SUMMA canister via the 1/4-inch Teflon
tubing.
3. Open the valve on SUMMA canister. The soil
gas sample is drawn into the canister by
pressure equilibration. The approximate
sampling tune for a 6-L canister is 20 minutes.
4. Site name, sample location, number, and date
must be recorded on a chain of custody form
and on a blank tag attached to the canister.
3.8 CALCULATIONS
3.8.1 Field Screening Instruments
Instrument readings are usually read directly from
the meter. In some cases, the background level at
the soil gas station may be subtracted:
Final Reading
Sample Reading -
Background
3.8.2 Photovac GC Analysis
Calculations used to determine concentrations of
individual components by Photovac GC analysis are
beyond the scope of this SOP and are covered hi
ERT SOP #2109, Photovac GC Analysis for Soil,
Water and Air/Soil Gas.
3.9 QUALITY ASSURANCE/
QUALITY CONTROL
3.9.1 Field Instrument Calibration
Consult the manufacturers' manuals for correct use
and calibration of all instrumentation. The HNU
should be calibrated at least once a day.
3.9.2 Gilian Model HFS113A Air
Sampling Pump Calibration
Flow should be set at approximately 3.0 L/min;
accurate flow adjustment is not necessary. Pumps
should be calibrated prior to bringing into the field.
3.9.3 Sample Probe Contamination
Sample probe contamination is checked between
each sample by drawing ambient air through the
probe via a Gilian pump and checking the response
of the HNU PI 101. If HNU readings are higher
than background, replacement or decontamination
is necessary.
Sample probes may be decontaminated simply by
drawing ambient air through the probe until the
HNU reading is at background. More persistent
contamination can be washed out using methanol
and water, then air drying. Having more than one
probe per sample team will reduce lag times
between sample stations while probes are
decontaminated.
3.9.4 Sample Train Contamination
The Teflon line forming the sample train from the
probe to the Tedlar bag should be changed on a
daily basis. If visible contamination (soil or water)
is drawn into the sampling train, it should be
changed immediately. When sampling in highly
contaminated areas, the sampling train should be
purged with ambient air, via a Gilian pump, for
approximately 30 seconds between each sample.
After purging, the sampling train can be checked
using an HNU, or other field monitoring device, to
establish the cleanliness of the Teflon line.
3.9.5 Field Blank
Each cooler containing samples should also contain
one Tedlar bag of ultra-zero grade air, acting as a
field blank. The field blank should accompany the
samples in the field (while being collected) and
when they are delivered for analysis. A fresh blank
must be provided to be placed hi the empty cooler
pending additional sample collection: One new field
blank per cooler of samples is required. A chain of
custody form must accompany each cooler of
samples and should include the blank that is
dedicated to that group of samples.
3.9.6 Trip Standard
Each cooler containing samples should contain a
Tedlar bag of standard gas to! calibrate the
16
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analytical instruments (Photovac GC, etc.). This
trip standard will be used to determine any changes
in concentrations of the target compounds during
the course of the sampling day (e.g., migration
through the sample bag, degradation, or
adsorption). A fresh trip standard must be provided
and placed in each cooler pending additional sample
collection. A chain of custody form should
accompany each cooler of samples and should
include the trip standard that is dedicated to that
group of samples.
3.9.7 Tedlar Bag Check
Prior to use, one bag should be removed from each
lot (case of 100) of Tedlar bags to be used for
sampling and checked for possible contamination as
follows: the test bag should be filled with ultra-zero
grade air; a sample should be drawn from the bag
and analyzed via Photovac GC or whatever method
is to be used for sample analysis. This procedure
will ensure sample container cleanliness prior to the
start of the sampling effort.
3.9.8 SUMMA Canister Check
From each lot of four cleaned SUMMA canisters,
one is to be removed for a GC/MS certification
check. If the canister passes certification, then it is
re-evacuated and all four canisters from that lot are
available for sampling.
If the chosen canister is contaminated, then the
entire lot of four SUMMA canisters must be
recleaned, and a single canister is re-analyzed by
GC/MS for certification.
3.9.9 Options
Duplicate Samples
A minimum of 5% of all samples should be
collected in duplicate (i.e., if a total of 100 samples
are to be collected, five samples should be
duplicated). In choosing which samples to
duplicate, the following criterion applies: if, after
filling the first Tedlar bag, and, evacuating the well
for 15 seconds, the second HNU (or other field
monitoring device being used) reading matches or
is close to (within 50%) the first reading, a
duplicate sample may be taken.
Spikes
A Tedlar bag spike and Tenax tube spike may be
desirable in situations where high concentrations of
contaminants other than the target compounds are
found to exist (landfills, etc.). The additional level
of QA/QC attained by this practice can be useful in
determining the effects of interferences caused by
these non-target compounds. SUMMA canisters
containing samples are not spiked.
3.10 DATA VALIDATION
For each target compound, the level of
concentration found hi the sample must be greater
than three times the level (for that compound)
found in the field blank which accompanied that
sample to be considered valid. The same criteria
apply to target compounds detected in the Tedlar
bag pre-sampling contamination check.
3.11 HEALTH AND SAFETY
Because the sample is being drawn from
underground, and no contamination is introduced
into the breathing zone, soil gas sampling usually
occurs in Level D, unless the sampling location is
within the hot zone of a site, which requires Level
B or Level C protection. However, to ensure that
the proper level of protection is utilized, constantly
monitor the ambient air using the HNU PI 101 to
obtain background readings during the sampling
procedure. As long as the levels in ambient air do
not rise above background, no upgrade of the level
of protection is needed.
Also, perform an underground utility search prior to
sampling (see section 3.4.4). When working with
potentially hazardous materials, follow U.S. EPA,
OSHA, and specific health and safety procedures.
17
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4.0 General Surface Geophysics: SOP #2159
4.1 SCOPE AND APPLICATION
This Standard Operating Procedure (SOP) describes
the general procedures used to acquire surface
geophysical data. This data is used for delineating
subsurface waste, and for interpreting geologic,
hydrogeologic or other data related to hazardous
waste site characterization.
The media pertinent to these surface geophysical
methods are soil/rock and groundwater. The
sensitivity or minimum response of a given method
depends on the comparison of the object or area of
study to that of its background (i.e., what the
media's response would be like without the object
of study). Therefore, the suitability of surface
geophysical methods for a given investigation must
be judged on the object's ability to be measured and
the extent to which the specific setting of the study
interferes with the measurement.
The surface geophysical method(s) selected for
application at a site are dependent on site
conditions, such as depth to bedrock, depth to
target, urban disturbances (fences, power lines,
surface debris, etc.) and atmospheric conditions.
Detectability of the target is dependent on the
sensitivity of the instrument and the variation of the
field measurement from the ambient noise.
Ambient noise is the pervasive noise associated with
an environment. Therefore, the applicability of
geophysical methods at a given site is dependent on
the specific setting at that site.
Five geophysical methods may be utilized in
hazardous waste site characterization:
magnetometry, electromagnetics, resistivity,
seismology and ground penetrating radar (GPR).
Magnetometers may be used to locate buried
ferrous metallic objects and geologic information.
Electromagnetic methods can be used to determine
the presence of metals, electrical conductivity of the
terrain, and geologic information. Resistivity
methods are used to determine the electrical
resistivity of the terrain and geologic information.
Seismic methods are useful in determining geologic
stratigraphy and structure. GPR may be used to
locate disturbance in the soil (i.e., trenches, buried
utilities and fill boundaries) and some near-surface
geologic information.
These procedures may be varied or changed as
required, dependent on site conditions, equipment
limitations or limitations imposed by the procedure.
In all instances, the procedures employed should be
documented and associated with the final report.
4.2 METHOD SUMMARY
4.2.1 Magnetics
A magnetometer is an instrument which measures
magnetic field strength in units of gammas
(nanoteslas). Local variations, or anomalies, in the
earth's magnetic field are the result of disturbances
caused mostly by variations in concentrations of
ferromagnetic material in the vicinity of the
magnetometer's sensor. A buried ferrous object,
such as a steel drum or tank, locally distorts the
earth's magnetic field and results in a magnetic
anomaly. The objective of conducting a magnetic
survey at a hazardous waste or groundwater
pollution site is to map these anomalies and
delineate the area containing buried sources of the
anomalies.
Analysis of magnetic data can allow an experienced
geophysicist to estimate the areal extent of buried
ferrous targets, such as a steel tank or drum.
Often, areas of burial can be prioritized upon
examination of the data, with high priority areas
indicating a near certainty of buried ferrous
material. In some instances, estimates of depth of
burial can be made from the data. Most of these
depth estimates are graphical methods of
interpretation, such as slope techniques and half-
width rules, as described by Nettleton (1976). The
accuracy of these methods is dependent upon the
quality of the data and the skill of the interpreting
geophysicist. An accuracy of 10 to 20 percent is
considered acceptable. The magnetic method may
also be used to map certain geologic features, such
as igneous intrusions, which may play an important
role in the hydrogeology of a groundwater pollution
site.
Advantages
Advantages of using the magnetic method for the
initial assessment of hazardous waste sites are the
19
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relatively low cost of conducting the survey and the
relative ease of completing a survey in a short
amount of time. Little, if any, site preparation is
necessary. Surveying requirements are not as
stringent as for other methods and may be
completed with a transit or Brunton-type pocket
transit and a non-metallic measuring tape. Often,
a magnetic investigation is a very cost-effective
method for initial assessment of a hazardous waste
site where buried steel drums or tanks are a
concern.
D/sac/vanfages
"Cultural noise" is a limitation of the magnetic
method in certain areas. Man-made structures that
are constructed with ferrous material, such as steel,
have a detrimental effect on the quality of the data.
Avoid features such as steel structures, power lines,
metal fences, steel reinforced concrete, pipelines
and underground utilities. When these features are
unavoidable, note their locations in a field notebook
and on the site map.
Another limitation of the magnetic method is the
inability of the interpretation methods to
differentiate between various steel objects. For
instance, it is not possible to determine if an
anomaly is the result of a steel tank, or a group of
steel drums, or old washing machines. Also, the
magnetic method does not allow the interpreter to
determine the contents of a buried tank or drum.
4.2.2 Electromagnetics
The electromagnetic method is a geophysical
technique based on the physical principles of
inducing and detecting electrical current flow within
geologic strata. A receiver detects these induced
currents by measuring the resulting time-varying
magnetic field. The electromagnetic method
measures bulk conductivity (the inverse of
resistivity) of geologic materials beneath the
transmitter and receiver coils. Electromagnetics
should not be confused with the electrical resistivity
method. The difference between the two techniques
is in the method which the electrical currents are
forced to flow in the earth. In the electromagnetic
method, currents are induced by the application of
time-varying magnetic fields, whereas in the
electrical resistivity method, current is injected into
the ground through surface electrodes.
Electromagnetics can be used to locate pipes, utility
lines, cables, buried steel drums, trenches, buried
waste, and concentrated contaminant plumes. The
method can also be used to map shallow geologic
features, such as lithologic changes and fault zones.
Advantages
Electromagnetic measurements can be collected
rapidly and with a minimum number of field
personnel. Most electromagnetic equipment used in
groundwater pollution investigations is lightweight
and easily portable. The electromagnetic method is
one of the more commonly used geophysical
techniques applied to groundwater pollution
investigations.
Disadvantages
The main limitation of the electromagnetic method
is "cultural noise". Sources of "cultural noise" can
include: large metal objects, buried cables, pipes,
buildings, and metal fences.
The electromagnetic method has limitations in areas
where the geology varies laterally. These can cause
conductivity anomalies or lineations, which might be
misinterpreted as contaminant plumes.
4.2.3 Electrical Resistivity'
The electrical resistivity method is; used to map
subsurface electrical resistivity structure, which is in
turn interpreted by the geophysicist to determine
the geologic structure and/or physical properties of
the geologic materials. Electrical 'resistivities of
geologic materials are measured in ohm-meters, and
are functions of porosity, permeability, water
saturation and the concentration of dissolved solids
in the pore fluids.
Resistivity methods measure the bulk resistivity of
the subsurface, as do the electromagnetic methods.
The difference between the two methods is in the
way that electrical currents are forced to flow in the
earth. In the electrical resistivity method, current is
injected into the ground through surface electrodes,
whereas hi electromagnetic methods currents are
induced by application of time-varying magnetic
fields.
Advantages
The principal advantage of the electrical resistivity
method is that quantitative modeling is possible
20
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using either computer software or published master
curves. The resulting models can provide accurate
estimates of depths, thicknesses and resistivities of
subsurface layers. The layer resistivities can then be
used to estimate the resistivity of the saturating
fluid, which is related to the total concentration of
dissolved solids in the fluid.
Disadvantages
The limitations of using the resistivity method in
groundwater pollution site investigations are largely
due to site characteristics, rather than in any
inherent limitations of the method. Typically,
polluted sites are located in industrial areas that
contain an abundance of broad spectrum electrical
noise. In conducting a resistivity survey, the
voltages are relayed to the receiver over long wires
that are grounded at each end. These wires act as
antennae receiving the radiated electrical noise that
in turn degrades the quality of the measured
voltages.
Resistivity surveys require a fairly large area, far
removed from pipelines and grounded metallic
structures such as metal fences, pipelines and
railroad tracks. This requirement precludes using
resistivity on many polluted sites. However, the
resistivity method can often be used successfully off-
site to map the stratigraphy of the area surrounding
the site. A general "rule of thumb" for resistivity
surveying is that grounded structures be at least half
of the maximum electrode spacing distance away
from the axis of the survey line.
Another consideration in the resistivity method is
that the fieldwork tends to be more labor intensive
than some other geophysical techniques. A
minimum of two to three crew members are
required for the fieldwork.
4.2.4 Seismic
Surface seismic techniques used in groundwater
pollution site investigations are largely restricted to
seismic refraction and seismic reflection methods.
The equipment used for both methods is
fundamentally the same and both methods measure
the travel-time of acoustic waves propagating
through the subsurface. In the refraction method,
the travel-time of waves refracted along an acoustic
interface is measured, and in the reflection method,
the travel-time of a wave which reflects or echoes
off an interface is measured.
The interpretation of seismic data will yield
subsurface velocity information, which is dependent
upon the acoustic properties of the subsurface
material. Various geologic materials can be
categorized by their acoustic properties or velocities.
Depth to geologic interfaces are calculated using the
velocities obtained from a seismic investigation.
The geologic information gained from a seismic
investigation is then used in the hydrogeologic
assessment of a groundwater pollution site and the
surrounding area. The interpretation of seismic
data indicates changes in lithology or stratigraphy,
geologic structure, or water saturation (water table).
Seismic methods are commonly used to determine
the depth and structure of geologic and
hydrogeologic units, to estimate hydraulic
conductivity, to detect cavities or voids, to determine
structure stability, to detect fractures and fault
zones, and to estimate ripability. The choice of
method depends upon the information needed and
the nature of the study area. This decision must be
made by a geophysicist who is experienced in both
methods, is aware of the geologic information
needed by the hydrogeologist, and is also aware of
the environment of the study area. The refraction
technique has been used more often than the
reflection technique for hazardous waste site
investigations.
Seismic Refraction Method
Seismic refraction is most commonly used at sites
where bedrock is less than 500 feet below the
ground surface. Seismic refraction is simply the
travel path of a sound wave through an upper
medium and along an interface and then back to the
surface. A detailed discussion of the seismic
refraction technique can be found in Dobrin (1976),
Telford, et. al. (1985), and Musgrave (1967).
Advantages: Seismic refraction surveys are more
common than reflection surveys for site
investigations. The velocities of each layer can be
determined from refraction data, and a relatively
precise estimate of the depth to different interfaces
can be calculated.
Refraction surveys add to depth information in-
between boreholes. Subsurface information can be
obtained between boreholes at a fraction of the cost
of drilling. Refraction data can be used to
determine the depth to the water table or bedrock.
In buried valley areas, refraction surveys map the
depth to bedrock. The velocity information
21
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obtained from a refraction survey can be related to
various physical properties of the bedrock. Rock
types have certain ranges of velocities and these
velocities are not always unique to a particular rock
type. However, they can allow a geophysicist to
differentiate between certain units, such as shales
and granites.
Disadvantages: The seismic refraction method
is based on several assumptions. To successfully
resolve the subsurface using the refraction method,
the conditions of the geologic environment must
approximate these assumptions:
• the velocities of the layers increase with
depth,
• the velocity contrast between layers is
sufficient to resolve the interface, and
• the geometry of the geophones in relation
to the refracting layers will permit the
detection of thin layers.
These conditions must be met for accurate depth
information.
Collecting and interpreting seismic refraction data
has several disadvantages. Data collection can be
labor intensive. Also, large line lengths are needed;
therefore, as a general rule, the distance from the
shot, or seismic source, to the first geophone station
must be at least three times the desired depth of
exploration.
Seismic Reflection Method
The seismic reflection method is not as commonly
used on groundwater pollution site investigations as
seismic refraction. In the seismic reflection method,
a sound wave travels down to a geologic interface
and reflects back to the surface. Reflections occur
at an interface where there is a change in the
acoustic properties of the subsurface material.
Advantages: The seismic reflection method
yields information that allows the interpreter to
discern between fairly discrete layers, so it is useful
for mapping stratigraphy. Reflection data is usually
presented in profile form, and depths to interfaces
are represented as a function of time. Depth
information can be obtained by converting time
sections into depth measurements using velocities
obtained from seismic refraction data, sonic logs, or
velocity logs. The reflection technique requires
much less space than refraction surveys. The long
offsets of the seismic source from the geophones,
common hi refraction surveys, are not required in
the reflection method. In some geologic
environments, reflection data can yield acceptable
depth estimates.
Disadvantages: The major disadvantage to
using reflection data is that a precise depth
determination cannot be made. Velocities obtained
from most reflection data are at least 10% and can
be 20% of the true velocities. The interpretation of
reflection data requires a qualitative approach. In
addition to being more labor intensive, the
acquisition of reflection data is more complex than
refraction data.
The reflection method places higher requirements
on the capabilities of the seismic equipment.
Reflection data is commonly used in the petroleum
exploration industry and requires a large amount of
data processing time and lengthy data collection
procedures. Although mainframe computers are
often used in the reduction and analysis of large
amounts of reflection data, recent advances have
allowed for the use of personal computers on small
reflection surveys for engineering purposes. In most
cases, the data must be recorded digitally or
converted to a digital format, to employ various
numerical processing operations. The use of high
resolution reflection seismic method? relies heavily
on the geophysicist, the computer capacity, the data
reduction and processing programs, resolution
capabilities of the seismograph and geophones, and
the ingenuity of the interpreter. Without these
capabilities, reflection surveys are not
recommended.
4.2.5 Ground Penetrating Radar
The ground penetrating radar (GPR) method is
used for a variety of civil engineering, groundwater
evaluation and hazardous waste site applications.
This geophysical method is the most site-specific of
all geophysical techniques, providing subsurface
information ranging in depth from several tens of
meters to only a fraction of a meter. A basic
understanding of the function of the GPR
instrument, together with a knowledge of the
geology and mineralogy of the site, can help
determine if GPR will be successful in the site
assessment. When possible, the GPR technique
should be integrated with other geophysical and
22
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geologic data to provide the most comprehensive
site assessment.
The GPR method uses a transmitter that emits
pulses of high-frequency electromagnetic waves into
the subsurface. The transmitter is either moved
slowly across the ground surface or moved at fixed
station intervals. The penetrating electromagnetic
waves are scattered at points of change in the
complex dielectric permittivity, which is a property
of the subsurface material dependent primarily upon
the bulk density, clay content and water content of
the subsurface (Olhoeft, 1984). The
electromagnetic energy which is scattered back to
the receiving antenna on the surface is recorded as
a function of tune.
Depth penetration is severely limited by attenuation
of the transmitted electromagnetic waves into the
ground. Attenuation is caused by the sum of
electrical conductivity, dielectric relaxation, and
geometric scattering losses in the subsurface.
Generally, penetration of radar frequencies is
minimized by a shallow water table, an increase in
the clay content of the subsurface, and in
environments where the electrical resistivity of the
subsurface is less than 30 ohm-meters (Olhoeft,
1986). Ground penetrating radar works best in dry
sandy soil above the water table. At applicable
sites, depth resolution should be between 1 and 10
meters (Benson, 1982).
The analog plot produced by a continuously
recording GPR system is analogous to a seismic
reflection profile; that is, data is represented as a
function of horizontal distance versus time. This
representation should not be confused with a
geologic cross section which represents data as a
function of horizontal distance versus depth.
Because very high-frequency electromagnetic waves
in the megahertz range are used by radar systems,
and time delays are measured in nanoseconds (10~9
seconds), very high resolution of the subsurface is
possible using GPR. This resolution can be as high
as 0.1 meter. For depth determinations, it is
necessary to correlate the recorded features with
actual depth measurements from boreholes or from
the results of other geophysical investigations.
When properly interpreted, GPR data can optimally
resolve changes in soil horizons, fractures, water
insoluble contaminants, geological features, man-
made buried objects, and hydrologic features such
as water table depth and wetting fronts.
Advantages
Most GPR systems can provide a continuous display
of data along a traverse which can often be
interpreted qualitatively in the field. GPR is
capable of providing high resolution data under
favorable site conditions. The real-time capability
of GPR results in a rapid turnaround, and allows
the geophysicist to quickly evaluate subsurface site
conditions.
Disadvantages
One of the major limitations of GPR is the site-
specific nature of the technique. Another limitation
is the cost of site preparation which is necessary
prior to the survey. Most GPR units are towed
across the ground surface. Ideally, the ground
surface should be flat, dry, and clear of any brush or
debris. The quality of the data can be degraded by
a variety of factors, such as an uneven ground
surface or various cultural noise sources. For these
reasons, it is mandatory that the site be visited by
the project geophysicist before a GPR investigation
is proposed. The geophysicist should also evaluate
all stratigraphic information available, such as
borehole data and information on the depth to
water table in the survey area.
4.3 SAMPLE PRESERVATION,
CONTAINERS, HANDLING AND
STORAGE
This section is not applicable to this SOP.
4.4 INTERFERENCES AND
POTENTIAL PROBLEMS
See section 4.2.1 for a discussion of limitations of
the magnetic method.
See section 4.2.2 for a discussion of limitations of
the electromagnetic method.
See section 4.2.3 for a discussion of limitations of
the electrical resistivity method.
See section 4.2.4 for a discussion of limitations of
the seismic refraction method and the seismic
reflection method.
23
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See section 4.2.5 for a discussion of limitations of
the ground penetrating radar (GPR) method.
4.5 EQUIPMENT/APPARATUS
4.5.1 Magnetics
• GEM GSM-19G
magnetometer/gradiometer, EDA OMNI
IV magnetometer/gradiometer,
Geonics 856AGX (with built-in datalogger)
or equivalent
• magnetometer base station
• 300-foot tape measure
• non-ferrous survey stakes (wooden or
plastic)
4.5.2 Electromagnetics
Geonics EM-31, EM-34 or equivalent
Polycorder datalogger
Dat 31Q software (data dump software)
300-foot tape measure
survey stakes
4.5.3 Electrical Resistivity
• DC resistivity unit (non-specific)
• 4 electrodes and appropriate cables (length
dependent on depth of survey)
• 1 or 2 12-volt car batteries
• 300-foot tape measure
4.5.4 Seismic
12- or 24-channel seismograph (Geometries
2401 or equivalent)
30 lOHz to MHz geophones (for
refraction)
30 50Hz or greater geophones (for
reflection)
300-foot tape measure
survey stakes
sledge hammer and metal plate or
explosives
4.5.5 Ground Penetrating Radar
GSSI SIR-8 or equivalent
80 Mhz, 100 Mhz or
antenna/receiver pit
200-foot cable
300-foot tape measure
300 Mhz
4.6 REAGENTS
This section is not applicable to this SOP.
4.7 PROCEDURES
Refer to the manufacturer's operating manual for
specific procedures relating to operation of the
equipment.
4.8 CALCULATIONS
Calculations vary based on the geophysical method
employed. Refer to the instrument-specific users
manual for specific formulae.
4.9 QUALITY ASSURANCE/
QUALITY CONTROL
The following general quality assurance activities
apply to the implementation of these procedures.
• All data must be documented on field data
sheets or within site logbooks.
• All instrumentation must be operated in
accordance with operating instructions as
supplied by the manufacturer, unless
otherwise specified in the work plan.
Equipment checkout and calibration
activities must occur prior to
sampling/operation, and they must be
documented. ,
Method-specific quality assurance procedures may
be found in the user's manual.
4.10 DATA VALIDATION
Evaluate data as per the criteria established in
section 4.9 above.
4.11 HEALTH AND SAFETY
When working with potentially hazardous materials,
follow U.S. EPA, OSHA and specific health and
safety procedures.
24
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APPENDIX A
Figures
25
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Figure 1: Sampling Augers
SOP #2012
TUBE
<;UGER
BUCKE
AUGER
26
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Figure 2: Sampling Trier
SOP #2012
d
IT
i V
5 .Si
-j L
1.27-2.54 cm
27
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Figure 3: Sampling Train Schematic
SOP #2149
VACUUM
BO
SAMPLING
PORT
1/4" TEFLON TUBING
1/4" I.D. THIN WALL
TEFLON TUBING
1/4" S.S.
SAMPLE PROBE
"QUICK CONNECT'
FITTING
MODELING
CLAY
SAMPLE
WELL
28
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APPENDIX B
HNU Field Protocol
29
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HNU Field Protocol
SOP #2149
Startup Procedure
1. Before attaching the probe, check the function
switch on the control panel to ensure that it is
in the "off position. Attach the probe by
plugging it into the interface on the top of the
readout module. Use care in aligning the
prongs in the probe cord with the socket: do
not force it.
2. Turn the function switch to the battery check
position. The needle on the meter should read
within or above the green area on the scale. If
not, recharge the battery. If the red indicator
light comes on, the battery needs recharging.
3. Turn the function switch to any range setting.
For no more than 2 to 3 seconds, look into the
end of the probe to see if the lamp is on. If it
is on, you will see a purple glow. Do not stare
into the probe any longer than three seconds.
Long term exposure to UV light can damage
the eyes. Also, listen for the hum of the fan
motor.
4. To zero the instrument, turn the function switch
to the standby position and rotate the zero
adjustment until the meter reads zero. A
calibration gas is not needed since this is an
electronic zero adjustment. If the span
adjustment setting is changed after the zero is
set, the zero should be rechecked and adjusted,
if necessary. Wait 15 to 20 seconds to ensure
that the zero reading is stable. If necessary,
readjust the zero.
Operational Check
1. Follow the startup procedure.
2. With the instrument set on the 0-20 range, hold
a solvent-based Magic Marker near the probe
tip. If the meter deflects upscale, the
instrument is working.
Field Calibration Procedure
1. Follow the startup procedure and the
operational check.
2. Set the function switch to the range setting for
the concentration of the calibration gas.
3. Attach a regulator (HNU 101-351) to a
disposable cylinder of isobutylene gas. Connect
the regulator to the probe of the HNU with a
piece of clean Tygon tubing. Turn the valve on
the regulator to the "on" position.
4. After 15 seconds, adjust the span dial until the
meter reading equals the concentration of the
calibration gas used. The calibration gas is
usually 100 ppm of isobutylene in zero air. The
cylinders are marked in benzene equivalents for
the 10.2 eV probe (approximately 55 ppm
benzene equivalent) and for the 11.7 eV probe
(approximately 65 ppm benzene equivalent).
Be careful to unlock the span dial before
adjusting it. If the span has to be set below 3.0
calibration, the lamp and ion chamber should
be inspected and cleaned as appropriate. For
cleaning of the 11.7 eV probe, only use an
electronic-grade, oil-free freon or similar water-
free, grease-free solvent.
5. Record in the field log: the instrument ID #
(EPA decal or serial number if the instrument
is a rental); the initial and final span settings;
the date and time; concentration and type of
calibration used; and the name of the person
who calibrated the instrument.
Operation
1. Follow the startup procedure, operational
check, and calibration check.
2. Set the function switch to the appropriate
range. If the concentration of gases or vapors
is unknown, set the function switch to the 0-20
ppm range. Adjust it as necessary.
3. While taking care not to permit the HNU to be
exposed to excessive moisture, dirt, or
contamination, monitor the work activity as
specified in the site health and safety plan.
4. When the activity is completed or at the end of
the day, carefully clean the outside of the HNU
with a damp disposable towel to remove any
30
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visible dirt. Return the HNU to a secure area plastic to prevent it from becoming contaminated
and place on charge. and to prevent water from getting inside in the
event of precipitation.
5. With the exception of the probe's inlet and
exhaust, the HNU can be wrapped in clear
31
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References
SOPS #2006, 2012, 2149
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de Vera, E.R., B.P. Simmons, R.D. Stephen, and D.L. Storm. 1980. Samplers and Sampling
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New Jersey Department of Environmental Protection. February, 1988. Field Sampling Procedures
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Roy F. Weston, Inc. 1987. Weston Instrumentation Manual, Volume I.
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SOP #2159
Magnetics
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California.
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Lilley, F. 1968. Optimum Direction of Survey Lines. Geophysics 33(2): 329-336.
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Redford, M.S. 1964. Airborne Magnetometer Surveys for Petroleum. Exploration: Aero Service
Corporation. Houston, Texas.
Vacquier, V. and others. 195L Interpretation of Aeromagnetic Maps: Geological Society of America.
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Electromagnetics
Duran, P.B. 1982. The Use of Electromagnetic Conductivity Techniques in the Delineation of
Groundwater Pollution Plumes: unpublished master's thesis, Boston University.
Grant, F.S. and G.F. West. 1965. Interpretation Theory in Applied Geophysics. McGraw-Hill Book
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Greenhouse, J.P., and D.D. Slaine. 1983. The Use of Reconnaissance Electromagnetic Methods to
Map Contaminant Migration. Ground Water Monitoring Review 3(2). \
Keller, G.V. and F.C. Frischknecht. 1966. Electrical Methods in Geophysical Prospecting. Pergamon
Press, Long Island City, New York.
McNeill, J.D. 1980. Electromagnetic Terrain Conductivity Measurements at Low Induction Numbers.
Technical Note TN-6, Geonics Limited. Mississauga, Ontario, Canada.
McNeill, J.D. 1980. EM34-3 Survey Interpretation Techniques. Technical Note TN-8, Geonics
Limited. Mississauga, Ontario, Canada.
McNeill, J.D. 1980. Electrical Conductivity of Soils and Rocks. Technical Note TN-5, Geonics
Limited. Mississauga, Ontario, Canada.
McNeill, J.D. and M. Bosnar. 1986. Surface and Borehole Electro-Magnetic Groundwater
Contamination Surveys, Pittman Lateral Transect, Nevada: Technical Note TN-22, Geonics
Limited. Mississauga, Ontario, Canada.
Stewart, M.T. 1982. Evaluation of Electromagnetic Methods for Rapid Mapping of Salt Water
Interfaces hi Coastal Aquifers. Ground Water 20.
Telford, W.M., L.P. Geldart, R.E. Sheriff, and DA. Keys. 1977. Applied Geophysics. Cambridge
University Press. New York, New York.
Electrical Resistivity
Bisdorf, RJ. 1985. Electrical Techniques for Engineering Applications. Bulletin of the Association of
Engineering Geologists 22(4).
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•U.S.Govarnment Printing Office: 1991 — 548-187/40577
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