environmental investigations usingions using versatile

Environmental Investigations UsingEnvironmental Investigations Using Versatile, VaporVersatile, Vapor--Permeable,Permeable,

AdsorbentAdsorbent--based Passive Samplersbased Passive Samplers

Jay W.Jay W. HodnyHodny, Ph.D. & George Sha, Ph.D w. & George ShawW. L. Gore & Associates, Inc.W. L. Gore & Associates, Inc.

77thth Passive Sampling Workshop and SymposiPa umussive Sampling Workshop and Symposi mReston, VAReston, VA

April 24April 24––26, 2026 070, 20 7

GORE™ Surveys: Investigating Air, Soil, and Water GORE, GORE-TEX and designs are trademarks of W. L. Gore & Associates © 2007 W. L. Gore & Associates, Inc. 1

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OutlineOutline

• Introduction

• Environmental investigations

– Passive sampling – soil gas, subslab soil gas, air

– Common applications

– Benefits

• GORE™ Module

– What it is and how it works

• Example

• New advances

– Concentration reporting – air, water

• Examples

GORE, GORE-TEX and designs are trademarks of W. L. Gore & Associates © 2007 W. L. Gore & Associates, Inc. 2

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Do you prefer an informative pictureDo you prefer an informative picture beforebefore an operation?an operation?

Where’s the problem?

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Do you prefer an informative pictureDo you prefer an informative picture beforebefore remediatingremediating??

Reconnaissance Tool • Type • Source • Extent

“Environmental X-ray”

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Common ApplicationsCommon Applications –– Passive SamplingPassive Sampling

• Site assessment (Conceptual Site Models)

• Vapor intrusion

• Remedial optimization

• Property transfer - Brownfields

• Monitoring

– Long-term GW

– Remediation

• Pipeline integrity

* - partial list


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BenefitsBenefits –– Passive SamplingPassive Sampling

• Rapid, inexpensive, unobtrusive installation & retrieval

• Minimal operator & field sampling error

• Time-integrated sampling

• ppt sensitivity

• Sensitivity to broad range of compounds VOCs, SVOCs, PAHs

• Minimizes sampling variability

• Virtually any soil and moisture condition

• No forced extraction of vapor

• No mechanical parts

• No energy required


Limitations

Mercury and vapor concentration, no longer a limitation.

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• Active soil gas and subslab soil gas

– Forced withdrawal of vapor

– Complex setup

• Potential for error

ComparisonComparison

Courtesy of ZEBRA Environmental Corporation

• Passive soil gas and subslab soil gas

– No forced withdrawal of vapor

– Simple setup

• Minimal error

Limitations

Mercury and vapor concentration, no longer a limitation.

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Passive

Volatile Semivolatile

D rie

r W

et te

r

Active

Sand

s C

l a y s

Shorter Sampling Longer Sampling

Time-integrated: Sensitive to a broader range of compounds, present in lower concentrations, in virtually any soil condition.

S il ts

S hal

low

G W

D

e ep

GW

Organic Compound Universe

Geo

logi

cal U

nive

rse

Why Passive Sampling?Why Passive Sampling?

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1) GORE-TEX® MembraneChemically-inert, waterproof, vapor permeable

2) Engineered sorbentsHydrophobic

VOCs, SVOCs, PAHs

3) Sample analysisEPA 8260/8270 or TO-15

Duplicate samples

Direct detection of organic compounds

Sample integrity protected

GOREGORETMTM ModulesModules

GORE-TEX® Membrane

1) GORE-TEX® Membrane • Chemically-inert, waterproof, vapor permeable•

2) Engineered sorbents • Hydrophobic• • VOCs, SVOCs, PAHs•

3) Sample analysis • EPA 8260/8270 or TO-15• • Duplicate samples•

• Direct detection of organic compounds• • Sample integrity protected•


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GORE™ ModuleGORE™ Module

String and cork

Insertion rod

Field Kit

Subsurface InstallationSubsurface Installation

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InstallationInstallation -- Soil Gas,Soil Gas, SubslabSubslab Soil Gas and AirSoil Gas and Air

Subslab Soil GasSoil Gas

Slam bar Hammer drill

Module insertion Angle beneath slab

Air

Crawlspace air

Indoor air


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InstallationInstallation –– Sediment and GroundwaterSediment and Groundwater

Sediment Groundwater

Vertical Profiling in Wells

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Remedial Optimization ExampleRemedial Optimization Example

Manufacturing Facility

Objective: optimize recovery well placementObjective: optimize recovery well placement

• Chlorinated compounds in groundwater

• 30ft weathered, “tight” clay (10-8), fractured bedrock

• Groundwater ~30ft depth

• Geophysical survey lacked resolution

• Active soil gas survey failed

• PETREX survey performed poorly

• 77 GORETM Modules, 30 x 4ft sample spacing


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SOURCE AREA

“Groundwater

Data”



“Soil Gas Data &

New Recovery

Well”


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Conclusions

• Sample spacing delineated suspect fracture

• TCE in groundwater detected in soil gas • Challenging site geology

• Recovery well location optimized

• 25x increase in fluid removal

• 75% increase in TCE removal


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Calculating ConcentrationsCalculating Concentrations

• Quantify (measure) uptake rate

– Experimental conditions

– Varying concentrations, conditions

– Air, water

• Exposure period

• Quantify (measure) mass desorbed

• Soil gas

– Eff. Diff.=ƒ[total porosity, water-filled porosity]* • Johnson-Ettinger VI model terms

• Millington-Quirk

• Conc = ƒ[volume=ƒ(uptake rate, time), mass, soil*]

• Approach – IH methods-solid, sorbent-based diffusion samplers • ASTM 6306 (1998); 6246 (1998); 4597 (1987)

• MDHS 70 (1990); 80 (1995); 27 (1983)


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Vapor Intrusion InvestigationVapor Intrusion Investigation

CrawlspaceSubslab

Basement

NAPL

GW Impact

Monitoring Well GORE Module


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Indianapolis site

• US EPA - IDEM

• Objective: – “First look”

• July

• VOCs, SVOCs, PAHs

– Guide next sampling • July, August

• “sampling boot camp”

Vapor Intrusion Concentration ExampleVapor Intrusion Concentration Example

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TCE Calculated vs Measured Concentrations

y = 7.0722x - 185.49

R2 = 0.9696

-2000

0

2000

4000

6000

8000

10000

12000

0 200 400 600 800 1000 1200 1400 1600

Gore TCE (ppbv)

Me

as

ure

d T

CE

(p

pb

v)

Courtesy of Todd McAlary, GeoSyntec Consultants

• 3 ft sample depth

• Excellent correlation

TCE (r^2 = 92%)

10.0

100.0

1000.0

10000.0

10.0 100.0 1000.0

Gore Concentration (ppbv)

TA

GA

Co

nc

en

tra

tio

n

(pp

bv

)

JulyJuly

AugustAugust


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• 3 ft sample depth

• One hour exposure

• Correlates spatially

• Matches P5

503053 – 2.7 ppmv 503055 - 8.8 ppmv

P-5 - 9.4 ppmv

503051 – 17.1 ppmv

TCETCE


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Groundwater Sampling ExampleGroundwater Sampling Example

Dry cleaner site – southeast US

• Chlorinated solvents in groundwater

• Shallow water table ~ 8ft.

• Up to four GORETM Modules per four wells – Vertical profile

– One hour exposure

• Slow purge (peristaltic pump); disposable bailer


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Groundwater Sampling ExampleGroundwater Sampling Example

PCE, TCE, cis-1,2-DCE (ug/L)

y = 1.1611x

R2 = 0.982 n = 12

0

5000

10000

15000

20000

25000

30000

35000

0 5000 10000 15000 20000 25000 30000 35000

Concentrations - Passive

Co

nce

ntr

atio

ns

-B

aile

r

c12DCE

TCE

PCE

Linear

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ConclusionsConclusions

GORETM Module - versatile, membrane-based passive sampler • Effective in broad scope of environmental investigations

• Sample virtually any media – Air, soil gas, water

• Inexpensive installation, retrieval & operation – Minimizes sampling error

• Concentration reporting – Relatively new capability

– Sound science

– Favorable data comparisons


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THANK YOU!THANK YOU!

The authors acknowledge:

Louise Parker, USACE

US EPA

IDEM

Todd McAlary, GeoSyntec Consultants

S & ME

For more information, contact:

[email protected]

[email protected]

410-392-7600

www.gore.com/surveys


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mailto:[email protected]

mailto:[email protected]

http://www.gore.com/surveys

environmental investigations usingions using versatile

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