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PRE-REMEDIAL SOIL VAPOR
AND AIR SAMPLINGMartyne Kieling
GeoScientist
New Mexico Environment Department
August 21, 2018
Discussion -2
How NMED Performs Pre-Remedial Soil Vapor (SV)
and Indoor Air (IA) Sampling.
The goal is to have defensible data that can be used
for the EPA CERCLA Hazardous Ranking System (HRS)
Subsurface Intrusion (SsI) Pathway.
Discussion -
3
Soil Vapor and Indoor Air Sampling Think - Design - Call
Methods Employed and Equipment UsedDrilling,
Vapor point install,
He leak check,
Mobile GC unit, and
Evacuated Canisters
Lessons Learned Along the Way
Questions
NMED Pre-Remedial SV and IA Sampling
4
For Superfund NMED follows a phased
Approach SV & IA Sampling
Site Inspection (SI)
Site Reassessment (SR)
Expanded Site Inspection (ESI)
7
Call Before You Drill!
Call before you Drill !
Free Locate service for public property and
Paid locate company for private property.
Are you trained (811 one call)?
Plan reconnaissance trip –
Mark areas for the locate service-
Don’t forget backup locations –
Silica dust is the newest requirement with
OSHA safety. Concrete dust should be kept
to a minimum, use a dust mask if
appropriate.
8
Design Your Area of Study
What questions are you trying to answer, does
each selected SV location provide information for
the HRS SsI pathway?
Is this for source identification?
Is this to determine where to select indoor air sample
locations for risk?
Or both?
Show rationale with location placements on a map.
Keep in mind high traffic areas and vandalism.
10
Design Your Area of Study
What influences contaminant pathways and
subsurface movement of SV at the Site.
Impervious surfaces or caps,
Sewer pipes and utility corridors,
Irrigation of parks & ballfields / irrigation ditches or
stream channels could create a doughnut hole effect.
Weather conditions – wind & barometric pressure
changes may influence indoor VI sample results.
11
Design Your Area of Study - Indoor
Who are you contacting? owners will influence where you sample. City, county, home owner (renter), active business or empty
lot.
Survey the building and contents. Don’t just leave the survey, the owner may not fill it out.
Go over the rules –
Windows & doors shut
No auto repair & garage door to the home closed
Remove chemical based craft items & cleaning chemicals.
Heat/air conditioning system exchange rate, fans, swamp-coolers (require open window/door)
13
Methods Employed and Equipment Used
Canister Size
Soil vapor – 1Liter
soft ball size
Indoor air – 6 Liter
basketball size
Flow Controller Rate
Soil vapor - 200ml/min
= 5 min
Indoor air – 8hr or 24
hr.
Methods Employed & Equipment Used14
Laboratory – Use when confirmatory or defensible data is needed.
◼ Select a Lab based on services & equipment –
Can it provide extras such as duplicate T, ferrules, nuts, Nylaflow or Teflon tubing, flow controller (set at the rate needed: 200ml/min for SV; or 8hr or 24hr for IA).
NMED uses private Laboratories for efficiency, cost savings and extras.
Methods Employed & Equipment Used15
Portable Gas Chromatograph –
NMED uses FROG-5000tm with Ellvintm software
by Defiant Technologies Inc. www.defiant-tech.com
Use for SI phase - determine areas with elevated
results.
◼ Determine if a potential for IA risk is a concern.
◼Where to focus IA sampling for the SR and ESI phase.
◼Where to step out/in with the next set of sample points
and where to take confirmatory SV samples for the SR
and ESI phase.
Results in real time -10 to 30 min
TCE+PCE 10 min run time
Chlorinated alkenes 30 min run time (VC, TCE, PCE, Cis1,2-DCE Trans1,2-DCE)
In-line diluter (extra cost)
Analyzes water, soil & air
Runs stand alone or with PC
Ellvintm software
Calibration lasts 3 weeks
Easy to use & set retention times
Provides graph overlay option
Can perform continuous runs
16
FROG-5000tm Defiant Technologies Inc.
18
NMED First Use of FROG/Canister Soil Gas
Comparison, (2016)
54
1516
0
983
1650
4751
199 199
713
1655
2741
785
0
0 0 0
1,440
3,050
8,530
257 272
1,350
0.48 2.15 0 8.94
-200
800
1800
2800
3800
4800
5800
6800
7800
TCE ug/m3
Sample Location
West Central Avenue, TCE Field Screening & Summa Data Results
FROG TCE ug/m3 Summa TCE ug/m3
Methods Employed & Equipment Used
AMS, Inc. www.ams-samplers.com20
Pre-drill hard
surface or auger
top 12 inches.
Ceramic fish-bubbler inserted into ¼ in. Teflon or Nylaflow
tubing. Both are industry standard & used by Blaine Hartman
www.hartmandeg.com 24
Open Hole Method - Drop tubing with tip into the borehole. Cap
tubing. Add clean sand, A 60 cc syringe is used for measuring the
volume for a 6 in. to 1 ft. sample collection zone.25
Build it like a well – Add dry bentonite and DI water at 1-2
foot lift intervals. Measure depth with a marked steel fish tape.
26
Add DI water to each lift directly to the top of the bentonite
layer (homemade water deliver system), this keeps the upper
part of the borehole dry. Repeat steps until near the surface.27
Alternate Methods – Speed Deploy in Small
30
-Insert fish-bubbler into tubing, slide tubing into a small diameter threaded pipe (hydraulic line).
Pipes can connect to extend to desired length and shorten for easy transport.
Insert pipe into borehole and then remove, leaving the sample tubing and tip in place.
Maintain Representative Sample
31
Equilibrate time (ideal =24 hours)
Consistent rates (200 ml/min) across all
instrumentation (PID, GilAir by Sensidyne, helium
meter, evacuated canisters and portable GC
Frog-5000tm)
Un-Even surface problem… use clean soil
32
Problems encountered….
Fairly even surface is
optimal for firm shroud
placement, to minimize He
loss during the leak test.
Use clean soil
Must keep concrete portion
of borehole open so
concrete patch can be
added later.
Use foil
Dielectric helium/hydrogen multi-gas MGD-2002 www.dielectrictechnologies.com
GilAir www.sensidyne.com/air-sampling-equipment/gilian-air-sampling-pumps
Shroud = homemade with standard hardware
33
-
Helium Shroud Downhole Leak Test Details
34
Equipment:
Digital Gillian pump set at 200mL/min, shroud-PVC Cap fitted with foam insulation and three ports, helium detector (preferably a Dielectric He/H Multi-gas Detector MGD-2002 with water trap wand), Tedlar bag(s), MityVack, caps for tubing or electrical tape, Silicon tubing for connections (with 0.2 mm less than the OD Teflon or Nylaflow tubes), helium canister with certified ultra-pure helium, PID, Field Sample form to record all SV installation, He leak test, and sample collection information.
Shroud Placement and Setup
Prior to performing shroud leak test, pre-set the digital Gillian pump to 200mL per min. The system purge time for the He leak test will take approximately 5 minutes to fill the Tedlar bag to a volume of 1000 mL (and to fulfill the purge volume requirement). The He shroud test will purge adequate volume to meet sample tubing and borehole purge requirements.
Clear and smooth area around soil vapor sample tubing. Insert tubing through the top hole in the shroud (it should be a snug fit). Attach the end of the sample tubing to a small piece of silicone tubing connected to the Gillian pump inlet.
To the Gillian outlet, place another small piece of silicone tubing and a 2-foot long piece of tubing (use another short piece of silicon tubing on the Tedlar inlet to connect the Tedlar bag to the end of the 2-feet of tubing).
On one side port of the shroud attach the He tank tubing with a short piece of silicone tubing, the connection should be tight. On the other shroud side tubing insert the initialized and running He detector.
Helium Shroud Downhole Leak Test Details cont….
36
Complete set up - holding pressure to the
shroud while He is added. Continue to
apply pressure to shroud while Tedlar fills
with the 1 L purge volume to be used for
the He test and PID measurement.
Helium Shroud Downhole Leak Test Details cont.
37
10 second collection of vapor with He
meter. Observe highest reading and
record. Must be less than 5% of shroud
concentration.
PID reading of entire 1-liter volume.
Look for the highest reading and
record. Insert loosely and apply slight
pressure to aid in evacuation of Tedlar
bag.
Evacuated Canister Shut-in Test39
Does the pressure hold steady for 1 min.?
If so you have secured the flow controller tight to canister.
Magnehelic gage
Wrenches (don’t over tighten)
Tubing & nut with ferrule.
Silicone tubing for tight fit
3-way Luer Lock valve and Luer Lock 60cc syringe
Binder clip
Evacuated Canister – dust cover Don’t forget to remove dust cover when you set it for collection!
40
Lessons Learned43
Two generators
were needed set in
parallel to have
enough power for
the AMS Drill.
Lessons Learned44
Vegetable shortening
can be used to
lubricate connectors
on the AMS drill rods
so threads come
apart easily.
Lessons Learned45
A Small piece of tubing to change diameter for a tight fit when filling Tedlar.
Beware of DIRTY Tedlar bags.
Tedlars leak over time through the membrane.
If possible collect blanks from your equipment. NMED uses the FROG-5000 to test its tubing and Tedlars.
Questions47
To be addressed at the end of the Session.
Contact Information:
Martyne Kieling, GeoScientist
NMED, Ground Water Quality Bureau - Superfund Oversight Section
martynekieling@state.nm.us
505-827-2340
48
Blaine Hartman Training
Practical Guide to Vapor Intrusion 2-Day Training course. www.hartmandeg.com
Thank you to LaDonna Turner EPA-R6 Site Assessment Manager (NM & OK) for supporting NMED–SOS work using Soil Vapor methods.
Thank you to Brenda Cook EPA-R6 for her Soil Vapor Intrusion HRS – SsI training and insight.
Acknowledgements
Achieve a Representative Sample50
Vapor Point Installation -
Install tubing with vapor tip and cap (vacuum cap or electrical tape)
Sand pack (clean graded #2/16 sand)
Bentonite seal (8-20 mesh granular bentonite)
Water delivery system (tubing and 60 ml syringe)
Equilibrate (ideal =24 hours, not always possible)
Leak test & Borehole/tubing purge -
Certified ultra pure helium (small tank), flow controller valve & hose.
Helium meter (Dielectric helium/hydrogen multi-gas MGD-2002) www.dielectrictechnologies.com
Shroud (PVC cap, top hole¼ in., 2 side ports with brass fittings, and soft pipe insulation)
GilAir www.sensidyne.com/air-sampling-equipment/gilian-air-sampling-pumps
Evacuated Canister & Flow Controller51
Talk with the Laboratory -
How much sample do they need for analysis?
Evacuated canisters come in different sizes, 6 Liter, 1Liter and smaller.
How many canisters do they have?
How much lead time do they need to prep canisters for you.
Can the Lab set a flow controller to (200ml/min)?
Does the flow controller have a straight intake or a goose neck?
Certified clean and with tags. (EPA Lab does not supply tags)
Does the Lab supply ferrules, nuts and duplicate T all for ¼ in?
Helium Shroud Downhole Leak Test Details cont….
53
Helium Leak Test (Step by Step): Make sure the He detector is on and the He supply tank main valve is open.
Staff # 1 Opens the Tedlar bag that is already connected to the Gillian pump sample line, applies pressure to the shroud with one or two hands, and will turn on the Gillian when Shroud HE reaches 50% saturation.
Staff #2: Operates the He tank and observes the He meter, and records readings.
Staff #1: opens Tedlar and applies pressure to shroud.
Staff # 2: Open the He valve slowly to allow He to enter the shroud. Add the He slowly and wait for a response in the He meter. There is a delay in the addition of He and the response occurring at the He detector. The HE meter will switch from ppbv to % saturation when enough HE is under the Shroud. Continue to slowly add He and watch for the delay on the meter until it reaches approximately 50% He saturation. Maintain Approx. 50% He under the shroud during purge vapor collection.
Staff #1: starts the Gillian pump.
Staff #2: Record the actual % saturation range reached.
Staff #1: Apply even pressure to the shroud while Tedlar fills for 5 min at 200mL/min. When the Tedlar is full, turn off the Gillian and close the Tedlar bag.
Staff #2: Turn off He tank. Record the purge collection time. Remove equipment and cap the sample collection tube. The shroud can be kept in place until a FROG or canister sample is collected or it can be removed and tubing capped until the follow-up team collects the SV sample.
Helium Shroud Downhole Leak Test Details cont…..
54
Analyze Purge Volume for He and VOC’s
Open the Tedlar and firmly hold the silicone tubing on the Tedlar to the He detector probe wand. Analyze the Tedlar purge sample with the He detector for 10 seconds. Record the highest He reading on the field sample form.
NOTE - The Tedlar sample should not contain more than 5% of maximum shroud He saturation.
For example: a 5% Tedlar detection from a He shroud that is saturated at 50% is equivalent to a Tedlar He sample detection of 2.5%. If the Tedlar sample is 2.5% or greater, the vapor point construction is likely compromised by ambient or surface interference.
Next, screen for VOCs levels to estimate FROG detections (and subsequently dilution procedures). Gently hold the PID probe in the silicone tubing to analyze for VOCs using the PID. Apply slight pressure to the Tedlar bag while the PID analyzes. Slowly compress the entire Tedlar bag contents looking for the highest VOC reading. Record the highest reading observed in the field sample form.
More on Tubing and Borehole Purge Volumes
55
Tubing Purge
Residual or stagnant air inside the gas probes and sampling train should be purged prior to sample collection to preserve sample-integrity. A standard purge consists of three to four sample tubing volume purges plus the 6- to 12-inch sand pack borehole volume.
If applicable, initial sample purges should be completed simultaneously with the Helium (He) shroud leak test. If returning to the site for follow-up sample collections, a second He leak test is not necessary. When performing subsequent sample collections, the system can be purged using the Gillian pump set at 200mL/min to slowly draw a desired purge volume.
More on Tubing and Borehole Purge Volumes
56
Calculated Volumes V=πr2h
Volume of Tubing (πR2 * Length);
Volume of Sand Pack Pore Space (πR2 * Porosity * Thickness)
Approximate Volumes for Tubing and Boreholes
Tubing ID Volume of 1 foot of tubing Volume of 10 feet of tubing
1/8 inch 2.4 mL 25 mL
3/16 inch 5.42mL 55 mL
Conversion - (1 cubic inch = 16.387mL)
Approximate Volumes for Tubing and Boreholes*
Borehole Diameter Volume of 1-foot borehole
5/8 inch 60 mL
1.5 inch 348 mL
2 inches 618 mL
*does not account for sand pack porosity
FROG-5000tm Defiant Technologies Inc.
57
Portable GC – FROG-5000tm with Ellvintm by
Defiant Technologies Inc. www.defiant-tech.com
Cost –
◼ Rental approx. $1000 weekly or $3000 monthly + $375 to calibrate for analyte(s).
◼ Purchase approx. $27,000 +$375 to calibrate (calibration lasts for 3 weeks).
Results – real time 10 to 30 min.
◼ TCE+PCE 10 min run time
◼ Chlorinated alkenes 30 min run time (VC, TCE, PCE, Cis1,2-DCE, and Trans1,2-DCE)
Training & customer service provided.
Air sampling attachment
In-line diluter (extra cost)
Analyzes water, soil & air
Runs stand alone or with PC
Ellvintm software
Calibration lasts 3 weeks
Easy to use & set retention
times
Overlay graphs
Can perform continuous runs
58
FROG-5000tm Defiant Technologies Inc.
AMS, Inc. www.ams-samplers.com
60
AMS manufactures hand augers, soil probes, gas vapor core samplers
COST
approx. $4, 653
5/8” OD - ¼” ID
- standard sample tubing and connections is 1/4”
Little Beaver ® http://www.littlebeaver.com/
61
Earth Drills & Augers
$4,500.-Lightweight, powerful, reliable
-High-speed auger rotation digs holes quickly and cleanly
-Torque-free digging eliminates kickback.
NMED uses two-person operation because it is a bit heavy.
62
Vapor Pin www.envirologek.com/shop/environmental-
investigation/gas-and-vapor-sampling
for repeat sampling.
Sub-slab – Sampling
Kerfoot Technologies Inc. www.kerfoottech.com
63
NMED – started SV sampling in 2016. We used equipment that was in our office. NMED stopped using this one.
-Expensive to maintain
-Impossible in caliche or pebble ground (7’ max depth if
easy soil)
-One time Shield point $13
-Small tubing size (5/8 OD, 3/16 ID)
-Continually lost rods in ground from broken thread connectors.
Macho Soil Gas Probe System
approx. $3,585
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