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)

5

Soil Vapor and Indoor Air Sampling

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Things to Think about Before you Start.

How close can you get to a building foot print?

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.

Map it out …. plan it out9

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)

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Design Your Area of Study - Indoor

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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.

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Evacuated canister and FROG-5000 co-located.

On-site windspeed and direction monitor.

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 Used19

Methods Employed & Equipment Used

AMS, Inc. www.ams-samplers.com20

Pre-drill hard

surface or auger

top 12 inches.

Methods Employed & Equipment Used21

Insert rod and drill adaptor, attach hammer drill.

Methods Employed & Equipment Used22

23

Retrieval Jack & Brace Board is used for uneven or soft surface.

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

Well log for Soil Vapor well28

Alternate Methods - Drill with Tubing Inside Drill Rod.

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Alternate Methods – Speed Deploy in Small

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-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

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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

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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

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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 & Flow Controller38

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!

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Secure canister & protect from moisture. chain and padlock / turndown tubing

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Lessons Learned42

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.

How the Data Collected Is Used46

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

49

Extra information

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?

Field Sample Form for VI & IA52

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

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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

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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.

59

Air sampling parts FROG-5000tm

AMS, Inc. www.ams-samplers.com

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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.

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Vapor Pin www.envirologek.com/shop/environmental-

investigation/gas-and-vapor-sampling

for repeat sampling.

Sub-slab – Sampling

Kerfoot Technologies Inc. www.kerfoottech.com

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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