Quantitative Passive DiffusiveQuantitative Passive ... 7/McAlary AWMA...Quantitative Passive DiffusiveQuantitative Passive Diffusive--Adsorptive Sampling Techniques for ... • Introduction to quantitative passive sampling ... qualitative! 8

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  • Quantitative Passive DiffusiveQuantitative Passive Diffusive--Adsorptive Sampling Techniques for Adsorptive Sampling Techniques for

    Vapor Intrusion AssessmentVapor Intrusion AssessmentVapor Intrusion AssessmentVapor Intrusion Assessment

    ESTCP Project 08 30ESTCP Project 08-30

    T M Al H G lt T G ki S S th thT. McAlary, H. Groenevelt, T. Gorecki, S. Seethapathy, D. Crump, P.Sacco, H. Hayes, M. Tuday, B.

    Schumacher, J. Nocerino, P. Johnson

    AWMA Specialty Conference Vapor Intrusion 2010

    September 30, 2010Chi IL

    11

    Chicago, IL

  • Outline Challenges with conventional sampling

    Introduction to quantitative passive sampling

    Comparative Studies Comparative Studies ESTCP Project 08-30 NAVY SPAWAR Projectj

    Summary of Findings to date

    22

  • Challenges withgConventional Sampling

    33

  • Summa Canister and TO-15

    Complex procedure, requires special training ($)

    Must be cleaned and certified ($)

    Bulky ($) to ship and handleBulky ($) to ship and handle

    Maximum ~24 hour samples

    Costly: $200 to $300/sample, depending on reporting limit

    Not useful for analytes heavier than naphthalene (poor recovery)

    4444

  • 55

  • Automatic Thermal Desorption Tubes / TO-17

    Typically customized for each application high level of training required

    Allows longer than 24-hour samples, but the pump must run reliably throughout the sampling periodsampling period

    Capable of a larger list of analytes

    Typically

  • Introduction to Quantitative QPassive Sampling

    77

  • Quantitative Passive Sampling Expose a sampler for a known time Ship to laboratory for analysis of adsorbed mass Calculate concentration

    M C0 = concentration of analyte in air (g/m3)

    tkMC 10

    M = mass of analyte collected by the sorbent (pg)

    k-1 = uptake rate (mL/min)

    Uptake rate is unique to each sampler/analyte pair

    tk t = sampling time (min) Uptake rate is unique to each sampler/analyte pair

    Usually requires expensive controlled experiments Some passive samplers dont control uptake qualitative!

    88

  • Benefits of Passive Sampling Simple (minimal training)

    L i Less expensive Low reporting limits with no premium cost

    Ti i ht d t ti Time-weighted average concentration(up to a week or a month if needed)

    S ll t hi di t t d l Smaller easy to ship, discrete to deploy Long history of use in Industrial Hygiene

    Oth b fit i t h l Other benefits unique to each sampler

    99

  • ESTCP Study TeamOrganization Name RoleGeosyntec Consultants, Inc.Guelph (Canada)

    Todd McAlaryHester Groenevelt

    Overall project direction &reporting

    US EPA Labs, Las Vegas (NV) Brian SchumacherJohn Nocerino (D)

    Experimental Design &Statistics

    Arizona State University (AZ) Paul Johnson Practicality for Vapor IntrusionSitesSites

    University of Waterloo(Canada)

    Tadeusz GoreckiSuresh Seethapathy

    PDMS Membrane Sampler

    Cranfield University (UK) Derrick Crump ATD Passive and Active Samplers

    Fondazione Salvatore Maugeri(Italy)

    Paolo Sacco Radiello Samplers

    Columbia Analytical Services(CA)

    Michael TudayKu-Jih Chen

    High Conc. Laboratory TestingUltra II samplers & canisters(CA) Ku-Jih Chen Ultra II samplers & canisters

    Air Toxics Limited (CA) Heidi HayesStephen Disher

    Low Conc. Laboratory TestingATD Passive and Active Samplers

    International Team incl ding the labs most familiar ith each of the samplers

    1010

    International Team, including the labs most familiar with each of the samplers

  • Four Different Passive Samplers

    Waterloo Membrane S l TM

    Automated Thermal Desorption (ATD) T bSampler TM

    (1-D permeation across a

    b CS

    Tubes

    (1-D diffusion through air, thermal desorption)

    membrane, CS2extraction or thermal desorption)

    Radiello

    SKC Ultra II

    (Badge sampler,

    (Radial uptake through porous cylinder, thermal desorption or( g p1-D uptake

    through porous plate, thermal desorption)

    desorption or solvent extraction)

    1111

    p )

  • Desorption Methods

    Thermal desorptionThermal desorptionThermal desorptionThermal desorption

    Solvent

    Sorbent

    Solvent desorptionSolvent desorption

    1212

    Thermal desorption

  • Sorbent Media SelectionSorbent Description Sampling Properties

    Anasorb 747 Beaded active carbon

    High capacity for VOCs, solvent desorption

    Tenax TA Porous polymer Low capacity, medium to high boiling compounds, thermal

    60/80 mesh

    g pdesorption

    Non porous high capacity forCarbopack B

    60/80 mesh graphitized

    carbon black

    Non-porous, high capacity for VOCs, thermal desorption

    1313

    There are many, many more sorbents available

  • Laboratory Analyte List

    43

    Selected to span a range of compounds of interest for vapor intrusion studies

    1414

    Selected to span a range of compounds of interest for vapor intrusion studiesChlorinated ethenes, ethanes, methanes, and VOCs of differing solubility and sorptive properties

  • Low Concentration Tests:To Mimic Indoor and Outdoor Air ConditionsTo Mimic Indoor and Outdoor Air Conditions

    Concentration : 1, 50 and 100 ppbvTemperature: 22, 25, 28 CTemperature: 22, 25, 28 CHumidity: 30, 60 and 90% RHFace velocity: 0.01, 0.2 and 0.4 m/sExposure time: 1 4 and 7 days

    High Concentration Tests:

    Exposure time: 1, 4 and 7 days

    High Concentration Tests:To Mimic Soil Gas Conditions

    C t ti 1 10 d 100Concentration : 1, 10 and 100 ppmvTemperature: ambientHumidity: 90-100%Face velocity: very low (5x10-5 m/s)

    1515

    Face velocity: very low (5x10 5 m/s)Exposure time: 30 minutes

  • Exposure Chamber Conditioned gas enters at

    bottom and flows past lsamplers

    Samplers rotate on a carousel to control facecarousel to control face velocity

    Baffles help to minimize t b lturbulence

    All surfaces passivated to minimize adsorptionminimize adsorption

    1616

  • Exposure Chamber (contd)Off th h lf All fOff the shelf glassware, modified by glass blower

    All surfaces passivated

    glass-blower

    Surrounded by tube of circulating fluid and insulated for temperature controlcontrol

    1717

  • 1818

  • Inter-Laboratory TestingSecondary #ofSamplersto

    SamplerType HomeLaboratory Laboratories EachLaboratory

    W t l M b Ai T i LtdWaterlooMembraneSampler UniversityofWaterloo

    AirToxicsLtd2

    AirzoneOne

    ATD Tubes with Tenax TA Air Toxics Ltd

    ColumbiaAnalyticalServices 2ATDTubeswithTenaxTA AirToxicsLtd Services 2

    UniversityofWaterloo

    ATDTubeswithb k Air Toxics Ltd

    ColumbiaAnalyticalServices 2CarboPackB AirToxicsLtd 2

    UniversityofWaterloo

    SKCUltra ColumbiaAnalyticalServicesAirToxicsLtd

    2ServicesAirzoneOne

    Radiello FondazioneSalvatoreMaugeri

    ColumbiaAnalyticalServices 2

    Air Toxics Ltd

    1919

    AirToxicsLtd

  • Interlab Test Youden Plot

    (blank contamination)

    2020

    Most results show good agreement between labsMEK was problematic

  • ANOVA TestingSet the five factors at their midpoints, and run test multiple times

    to determine variance from experimental procedures

    Factor Units Center Value

    Concentration ppb 50

    Temperature C 20Temperature C 20

    Gas Flow Velocity m/s 0.2

    Sampling Duration days 4

    Relative Humidity % 60

    2121

    e at ve u d ty % 60

  • Fractional Factorial TestingA series of experiments strategically changing the 5 key factors

    Concentration

    Temperature

    Face Velocity

    Sample Time

    HumidityHumidity

    2222

  • Chamber Test Results to DateChamber Test Results to Date

    2323

  • Chamber Test Results to DateChamber Test Results to Date

    (l bi )(low bias)

    2424

  • Chamber Test Results to DateChamber Test Results to Date

    (blank)(blank)

    (1-day)

    (Calculated Uptake Rate)

    2525

  • Chamber Test Results to DateChamber Test Results to Date

    (high bias)

    ?

    ?

    2626

  • Chamber Test Results to DateChamber Test Results to Date

    2727

  • Field Testing (SPAWAR/NESDI)Comparative sampling of indoor air, outdoor air, and soil vapor

    Indoor Air:

    ATD Tubes3M OVM 3500RadielloSKC Ult IISKC Ultra IIWaterloo Membrane

    VersusVersus

    6-day Summas

    With

    3 Replicates

    2828

    Acknowledgements to Ignacio Rivera and Bart Chadwick of SPAWAR for Support

    p

  • Indoor Air (3 Locations in Triplicate)Indoor Air (3 Locations in Triplicate)Indoor Air AverageTrichloroethene

    8

    10Indoor Air - AverageTrichloroethene

    SummaWMS3M OVM

    (Anasorb 747)(Activated carbon wafer)

    6

    8

    m3)

    ATDRadielloSKC Ultra

    Each bar is an average of the three

    (Chromosorb 106)(Activated charcoal)

    (Chromosorb 106)

    4

    atio

    n (

    g/m Each bar is an average of the three

    samples collected at that location

    2

    Con

    cent

    ra

    0

    IA-1 IA-2 IA-3 Average

    C

    Sample Location

    2929

    The low bias for SKC is believed to be due to sorbent selection (Chromosorb 106 worked well for ATD, but SKC has 20X higher uptake rate)TCE was the dominant compound

  • SubSub--Slab SamplingSlab SamplingTwo types:

    1) Fully passive (drop and cork for 24 hours)

    2) Semi-passive(drop and purge

    ith PID f 10with PID for 10 minutes)

    3030

  • SPAWAR Subslab DataSPAWAR Subslab DataFully passive samples (left)

    Fully Passive With Purging

    showed Starvation Effect in proportion to

    t k tuptake rate

    Much less starvation when PID used to purgePID used to purge gas from hole during 10 min sampling interval

    3131

    p g

  • Starvation Factor vs Uptake RateStarvation Factor vs Uptake Rate1000.0

    WMS cis-1,2-DichloroetheneWMS Trichloroethene

    Starvation Factor = Summa concnPassive concn

    100.0

    TrichloroetheneSKC cis-1,2-DichloroetheneSKC Trichloroethene

    on F

    acto

    r

    Radiello TrichloroetheneATD cis-1,2-

    10.0

    Star

    vatio

    ATD cis 1,2DichloroetheneATD Trichloroethene

    3M OVM i 1 2

    1.00.01 0.1 1 10 100

    Uptake Rate (ml/min)3M OVM cis-1,2-Dichloroethene3M OVM Trichloroethene

    3232

    Consider a custom low-uptake sampler

  • Modified Uptake RatesModified Uptake Rates

    WMS Sampler

    ATD Tube & Pinhole Cap

    SKC Ultra II and 12-hole Cap

    Reduce the uptake rate by reducing the area

    3333WMS Pinhole Sampler

    p y gLower uptake = less starvation

  • Passive Soil Gas Passive Soil Gas Utah HouseUtah House

    3434

  • 6 Passive Samplers6 Passive Samplers(Tenax) (Carbopack) (Cap)

    Uptake rates: 0.01 to 75 mL/min

    Void space was larger than SPAWAR sub-slab sampling

    3535

  • 6 Passive Probes + 1 Conventional6 Passive Probes + 1 Conventional

    Modified Latin Square TestAdded one Duplicate

    3636

    Added one DuplicateTested 1 to 12 day exposuresDrop the sampler/Purge 3 PV

  • Active Sampler DataActive Sampler Data120

    140

    TCE in Summa and Hapsite GC/MSPSG-1PSG-2PSG-3PSG-4PSG-5

    60

    80

    100

    trat

    ion

    (ppb

    v)

    PSG-6Summa - PSG-1Summa - PSG-2Summa - PSG-3Summa - PSG-4Summa - PSG-5

    20

    40

    60

    Con

    cent Summa - PSG-6

    Linear (PSG-1)Linear (PSG-2)Linear (PSG-3)Linear (PSG-4)Linear (PSG-5)

    007/16/10 07/21/10 07/26/10 07/31/10 08/05/10 08/10/10 08/15/10 08/20/10 08/25/10 08/30/10 09/04/10 09/09/10

    Sampling Date

    ( )Linear (PSG-6)

    160 1,1-DCE in Summa and Hapsite GC/MSPSG-1PSG-2PSG-3PSG 4

    100

    120

    140

    on (p

    pbv)

    PSG-4PSG-5PSG-6Summa - PSG-1Summa - PSG-2Summa - PSG-3

    40

    60

    80

    Con

    cent

    ratio Summa - PSG-4

    Summa - PSG-5Summa - PSG-6Linear (PSG-1)Linear (PSG-2)Linear (PSG-3)

    3737

    0

    20

    07/16/10 07/21/10 07/26/10 07/31/10 08/05/10 08/10/10 08/15/10 08/20/10 08/25/10 08/30/10 09/04/10 09/09/10

    Sampling Date

    ( )Linear (PSG-4)Linear (PSG-5)Linear (PSG-6)

  • Fully Passive Fully Passive Deep 2Deep 2--inch Probesinch Probes

    C/Co = Passive data divided by Mean of all Hapsite data

    3838

    All but about 3 of these measurements are within a half order of magnitudeLonger samples with weaker sorbent show losses (Tenax)

  • Fully Passive Fully Passive Deep 2Deep 2--inch Probesinch Probes

    Longer samples show losses with both Carbopack and Tenax for ATD Tubes

    3939

    Consistent with theory for incomplete retention (11DCE is 3X less sorptive than TCE)

  • Starvation Factor Versus Uptake RateStarvation Factor Versus Uptake Rate1000

    100

    1000

    Losses from Tenax

    10

    or (C

    o/C

    )

    1

    vatio

    n Fa

    cto

    0.1

    Star

    v

    0.010.01 0.1 1 10 100 1000

    4040

    Uptake Rate (mL/min)

    After removing artifacts of weak sorbent, trend is encouraging

  • FlowFlow--Through CellsThrough Cells

    Why worry about starvation at all?J st p rge soil gas past the sampler at a modest rate

    4141

    Just purge soil gas past the sampler at a modest rateComparable to groundwater Low Flow Sampling Protocol

  • FlowFlow--Through Cell ResultsThrough Cell Results

    4242

    Flow-through cell neutralizes the starvation effectVariability about 1 order of magnitude, but so did Summa cans

  • Interim Conclusions Encouraging results to dateEncouraging results to date

    No samplers eliminatedNo samplers eliminated Challenges with highly sorptive or highly soluble compoundsChallenges with highly sorptive or highly soluble compounds Challenges with very high humidity or long exposures for Challenges with very high humidity or long exposures for

    some sampler/sorbent combinationssome sampler/sorbent combinationssome sampler/sorbent combinationssome sampler/sorbent combinations Much better understanding of how to avoid starvation for soil Much better understanding of how to avoid starvation for soil

    gas sampling gas sampling quantitative results are likely feasiblequantitative results are likely feasibleg p gg p g q yq y Modifications can overcome some of the limitationsModifications can overcome some of the limitations

    Custom sorbents and uptake rates Custom sorbents and uptake rates Based on theory & dataBased on theory & data

    This is roughly the halfThis is roughly the half--way point way point stay tuned!stay tuned!

    4343

  • Questions/Comments?Questions/Comments?Questions/Comments?Questions/Comments?

    tmcalary@geosyntec.com

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