Volatile Petroleum Hydrocarbon (VPH) Analysis: An Evaluation of the Potential for False Positive Bias Presented by:

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Richard J. Rago; Haley & Aldrich

IPEC

Jane Parkin Kullmann; Haley & Aldrich

31 October 2012

Haley & Aldrich, Inc.

Outline • Overview of petroleum analytical methods • VPH method specifics, integration, calculation, and adjustments • 2000 and 2011 studies of false positives • Current Case Study • Alternative Strategies

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Analytical approaches to quantitation of petroleum-related compounds • Releases of petroleum products comprise a major source of environmental contamination • Although petroleum products may contain complex and variable mixtures of hydrocarbons, some states still rely on traditional, inexact analytical approaches for petroleum identification and quantitation – e.g.: • indicator compounds (i.e., BTEX) • a single “Total Petroleum Hydrocarbon” (TPH) concentration

• Analyses for BTEX and TPH provide little or no information on the specific hydrocarbon composition or toxicity of various petroleum products 3

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Chromatogram of diesel (typical) Key point: varying results achieved with BTEX and TPH

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Initial development of VPH and EPH methods in Massachusetts • Interim Final Petroleum Report: Development of HealthBased Alternative to the Total Petroleum Hydrocarbon (TPH) Parameter (Massachusetts Department of Environmental Protection, 1994) • Draft methods released (1995) • Implementation of VPH/EPH Approach issues paper (1996) • Characterizing Risks Posed by Petroleum Contaminated Sites: Implementation of the MADEP VPH/EPH Approach FINAL POLICY; October 31, 2002; Policy #WSC-02-411

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EPH/VPH analysis • MassDEP Petroleum Analytical Methods: • Gas chromatography (GC) methods: • Volatile Petroleum Hydrocarbons (VPH) method • Extractable Petroleum Hydrocarbons (EPH) method • Toxicological-based approach to characterize and evaluate risks posed by petroleum sites • Approach included analysis of target compounds with fractionation of petroleum into collective aliphatic and aromatic carbon ranges

• Methods since updated (May 2004, July 2010 [CAM])

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Representative Petroleum Distillates

Gasoline

No. 2 Fuel Oil/Diesel No. 6 Fuel Oil

Gasoline Range Org (GRO) Diesel Range Organics (DRO)

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Overview of Petroleum Hydrocarbons Petroleum Analytical Methods Approx. Soil Vapor Survey Range 8015 Headspace

418.1 Infrared (IR)

Gasoline Range Org (GRO) Diesel Range Organics (DRO) VPH EPH

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VPH analysis described elsewhere • Recognizing the limitations of “indicator only” approaches, several regulatory entities have promulgated draft and final methodologies that attempt to better characterize the risks posed by all hydrocarbons present • Maine Department of Environmental Protection • Washington Department of Ecology • Connecticut Department of Environmental Protection “RCPs” • Indiana Department of Environmental Management • NH (soon), LA, TX (TX1006), CA draft LUFT, FLA (MA) • WI (WI GRO TVPH), MT, NC • British Columbia Ministry of Environment and Europe (EUGRIS) • Used elsewhere 9

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VPH analysis described elsewhere (cont.) • MassDEP VPH method (without alteration) • Connecticut • Maine • North Carolina (for water; soil methods are various)

• MassDEP VPH method with modifications • Washington • Montana

• EPA TPH Method 8015D • Indiana

• FID analysis only • British Columbia 10

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Focus on MassDEP VPH method • MassDEP VPH Quantitation • Target Analytes: • Benzene, toluene, ethylbenzene, o-xylene, m/p-xylenes (BTEX) • Methyl tert-butyl ether (MTBE) • Naphthalene • Carbon ranges: • C5-C8 aliphatic hydrocarbons • C9-C12 aliphatic hydrocarbons • C9-C10 aromatic hydrocarbons

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VPH calibration for targets Methyl-t-butyl ether Benzene Toluene Ethylbenzene m-Xylene p-Xylene o-Xylene Naphthalene

area of peak Calibratio n Factor (CF) = concentrat ion purged ( µg / L)

2,5-Dibromotoluene (surrogate)

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VPH calibration for carbon ranges Pentane 2-Methylpentane 2,2,4-Trimethylpentane n-Nonane n-Decane n-Butylcyclohexane 1,2,4-Trimethylbenzene

Area summation of range components Range CF = Total concentrat ion purged ( µg / L)

2,5-Dibromotoluene (surrogate) Since erratic performance noted for n-nonane; calibration of C9-C12 aliphatics with n-decane and n-butylcyclohexane only is allowed; n-nonane retained in the calibration standard for use as a range marker compound.

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VPH method peak integration methods When quantifying on a peak area basis by external calibration, collective peak area integration for the hydrocarbon ranges must be from baseline (i.e., must include the unresolved complex mixture "hump" areas). For the integration of individual Target VPH Analytes, surrogate compounds, and internal standards, a valley-to-valley approach should typically be used, though this approach may be modified on a case-by-case basis by an experienced analyst. In any case, the unresolved complex mixture “hump” areas must not be included in the integration of individual Target VPH Analytes and surrogate compounds. (source: MassDEP vph0504)

valley to valley for targets 14

baseline to baseline for C-ranges Haley & Aldrich, Inc.

Chromatogram of lubricating oil (typical) Key point: note “hump” area not included, since this chromatogram is not integrated from baseline.

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Chromatogram of VPH calibration standards on both detectors

FID

T B

X E X X

N

mtbe

PID

Source: MassDEP vph0504

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VPH carbon ranges for gasoline standard

FID

PID

Source: MassDEP vph0504

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VPH method data adjustments • By definition, the collective concentrations of aliphatic and aromatic fractions of interest exclude the individual concentrations of Target VPH Analytes • Individual concentrations of the Target VPH Analytes are subtracted from the appropriate aliphatic range in which they elute • mtbe, benzene, and toluene concentrations are subtracted from C5-C8 aliphatic hydrocarbons • ethylbenzene and o-, m, and p-xylenes are subtracted from C9-C12 aliphatic hydrocarbons

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VPH method data adjustments (continued) • the collective concentration of C9-C10 Aromatic Hydrocarbons are subtracted from the collective concentration of C9-C12 Aliphatic Hydrocarbons • C9-C10 aromatics are not adjusted (nothing to adjust from them) • naphthalene and 2,5-dibromotoluene (surrogate) elute after C9-C12 range (nothing to adjust them from) • method specifies subtraction of the area counts of surrogate compound(s) from the collective area count of any range in which they elute (not applicable if the recommended surrogate 2,5-dibromotoluene is used)

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MassDEP VPH method language • Method “Scope and Application” recognizes that like all GC procedures, this method is subject to a "false positive" bias (from non-targeted hydrocarbon compounds). Confirmatory analysis is recommended if an applicable reporting or cleanup standard is exceeded and/or where co-elution of a non-targeted hydrocarbon compound is suspected. • Method-described interferences also reference that all compounds eluting on the PID chromatogram after o-xylene are identified by the method as aromatic hydrocarbons (resulting in the potential for overestimation of levels of aromatic hydrocarbons if late-eluting aliphatic compounds also respond to the PID). 20

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Studies of the VPH analytical method • Two different studies of the VPH method, each done twice • 2000 (five laboratories) • 2011 (four laboratories)

• One blind study included the analysis of aqueous control samples spiked only with halogenated ethanes • One blind study included the analysis of aqueous control samples spiked only with aromatic hydrocarbons

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Purpose of studies • Confirm whether chlorinated VOCs are reported in VPH, and if so, assess what approximate concentration of common chlorinated VOCs would trigger a “false” regulatory response requirement as petroleum • Assess whether aromatics alone will result in an aliphatic “remainder” result and if so, would they trigger a “false” regulatory response requirement for aliphatics • Determine whether laboratories will be inclined to advise the data user of these conditions

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VPH study with haloethanes 2000 and 2011 • Aqueous control samples spiked at 50 µg/L and 100 µg/L

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Chloroethane

1,1,1,2-tetrachloroethane

1,2-dibromoethane

1,1,2,2-tetrachloroethane

1,1-dichloroethane

tetrachloroethene

1,2-dichloroethane

1,1,1-trichloroethane

1,1-dichloroethene

1,1,2-trichloroethane

Cis-1,2-dichloroethene

trichloroethene

Trans-1,2-dichloroethene

Vinyl chloride

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VPH study with aromatics 2000 and 2011 • Aqueous control samples spiked at 24 µg/L and 300 µg/L

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Benzene

sec-butylbenzene

Toluene

tert-butylbenzene

Ethylbenzene

isopropylbenzene

Xylene (p)

4-isopropyltoluene

Xylene (m)

N-propylbenzene

Xylene (o)

1,2,4-trimethylbenzene

Styrene

1,3,5-trimethylbenzene

n-butylbenzene

naphthalene

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VPH analysis – GC columns (2011) • All labs used Restek RTX-502.2 column • 105 meter; 0.53 mm ID; 3.0 um film; diphenyl/dimethyl polysiloxane phase; Restek Cat # 10910

• All labs differed in GC conditions • Surrogate 2,5-dibromotoluene elution at 25-42 minutes • One lab also included surrogate 2,3,4-trifluorotoluene

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2000 VPH study analytical data results for samples spiked with halogenated ethanes TABLE I SUMMARY OF WATER QUALITY DATA LABORATORY SAMPLE DESIGNATION PREPARATION DATE

A

A

B

B

C

C

D

D

E

E

MCP

HA-2(OW) HA-3(OW) HA-2(OW) HA-3(OW) HA-2(OW) HA-3(OW) HA-2(OW) HA-3(OW) HA-2(OW) HA-3(OW)

Reportable

14-Apr-00 14-Apr-00 14-Apr-00 14-Apr-00 14-Apr-00 14-Apr-00 14-Apr-00 14-Apr-00 14-Apr-00 14-Apr-00

Concentration RCGW-1 HALOETHANE MIXTURE VPH (µg/L) C5-C8 Aliphatics

300

240

760

231

754

130

290

99

324

310

1000

C9-C12 Aliphatics

700

34

140

ND (100)

ND (100)

ND (50)

ND (50)

28.2

82.7

37

110

C9-C10 Aromatics

200

ND (20)

ND (40)

ND (100)

ND (100)

ND (50)

ND (50)

ND (20)

ND (20)

ND (5)

ND (5)

Methyl tert-butyl ether

70

ND (5)

ND (10)

ND (5)

ND (5)

ND (5)

ND (5)

ND (2)

ND (2)

ND (5)

ND (5)

Benzene

5

ND (1)

ND (2)

ND (5)

ND (5)

ND (5)

ND (5)

ND (2)

ND (2)

ND (5)

ND (5)

Toluene

1,000

ND (5)

ND (10)

ND (5)

ND (5)

ND (5)

ND (5)

ND (2)

ND (2)

ND (5)

ND (5)

700

ND (5)

ND (10)

ND (5)

ND (5)

ND (5)

ND (5)

ND (2)

ND (2)

ND (5)

ND (5)

Ethylbenzene Xylenes, mixture Naphthalene

5,000

ND (5)

ND (10)

ND (5)

ND (5)

ND (5)

ND (5)

ND (2)

ND (2)

ND (5)

ND (5)

140

ND (5)

ND (10)

ND (5)

ND (5)

ND (5)

ND (5)

ND (20)

ND (20)

ND (5)

ND (5)

NOTES AND ABBREVIATIONS: 1. Bold values indicate an exceedance of Method 1 (ALIPHATIC) criteria. 2. ND(2.5): Not detected; number in parentheses is the laboratory reporting limit. 3. VPH: Volatile Petroleum Hydrocarbons

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2011 VPH study analytical data results for samples spiked with halogenated ethanes TABLE I SUMMARY OF WATER QUALITY DATA LABORATORY SAMPLE DESIGNATION PREPARATION DATE

F

F

MCP HA-101 (OW) HA-102 (OW) Reportable 04-Aug-11 04-Aug-11 Concentration RCGW-1

G HA-101 (OW) 04-Aug-11

G HA-102 (OW) 04-Aug-11

120 ND (50) ND (50) ND (1) ND (1) ND (1) ND (1) ND (3) ND (5)

260 ND (50) ND (50) ND (1) ND (1) ND (1) ND (1) ND (3) ND (5)

H

H

HA-101 (OW) HA-102 (OW) 04-Aug-11 04-Aug-11

J HA-101 (OW) 04-Aug-11

J HA-102 (OW) 04-Aug-11

146 a ND (50) ND (50) ND (1) ND (2) ND (2) ND (2) ND (4) ND (3)

292 a ND (50) ND (50) ND (1) ND (2) ND (2) ND (2) ND (4) ND (3)

HALOETHANE MIXTURE VPH (µg/L) C5-C8 Aliphatics C9-C12 Aliphatics C9-C10 Aromatics Methyl tert-butyl ether Benzene Toluene Ethylbenzene Xylenes, mixture Naphthalene

300 700 200 70 5 1,000 700 5,000 140

155 ND (50) ND (50) ND (3) ND (2) ND (2) ND (2) ND (4) ND (4)

346 66.8 ND (50) ND (3) ND (2) ND (2) ND (2) ND (4) ND (4)

230 ND (100) ND (100) ND (1) ND (1) ND (1) ND (1) ND (3) ND (5)

440 110 ND (100) ND (1) ND (1) ND (1) ND (1) ND (3) ND (5)

a: “Value includes chlorinated ethylenes which are present in sample matrix.” NOTES AND ABBREVIATIONS: 1. Bold values indicate an exceedance of Method 1 (ALIPHATIC) criteria. 2. ND(2.5): Not detected; number in parentheses is the laboratory reporting limit. 3. VPH: Volatile Petroleum Hydrocarbons

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VPH study results for halogenated ethane-spiked samples • 2000 study • Range of C5-C8 aliphatics concentrations detected: • 99 to 310 µg/L in sample spiked at 50 µg/L level • 290 to 1,000 µg/L in sample spiked at 100 µg/L level • Range of C9-C12 aliphatics concentrations detected: • 28.2 to 37 µg/L in sample spiked at 50 µg/L level and 82.7 to 110 µg/L in sample spiked at 100 µg/L level

• 2011 study • Range of C5-C8 aliphatics concentrations detected: • 120 to 230 µg/L in sample spiked at 50 µg/L level • 260 to 440 µg/L in sample spiked at 100 µg/L level • Range of C9-C12 aliphatics concentrations detected: • C9-C12 aliphatics not detected in sample spiked at 50 µg/L level and 66.8 to 110 µg/L in sample spiked at 100 µg/L level 28

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Example chromatogram for halogenated ethane-spiked sample

C5-C8 Aliphatics C9-C12 Aliphatics

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2000 VPH study analytical data results for samples spiked with aromatic hydrocarbons TABLE II SUMMARY OF WATER QUALITY DATA LABORATORY SAMPLE DESIGNATION PREPARATION DATE

A MCP HA-2(OW) Reportable 14-Apr-00 Concentration RCGW-1

A HA-3(OW) 14-Apr-00

B HA-2(OW) 14-Apr-00

B HA-3(OW) 14-Apr-00

C HA-2(OW) 14-Apr-00

C HA-3(OW) 14-Apr-00

D HA-2(OW) 14-Apr-00

D HA-3(OW) 14-Apr-00

E HA-2(OW) 14-Apr-00

E HA-3(OW) 14-Apr-00

350 2300 1900 ND (10) 260 270 240 1150 280

ND (100) ND (100) 213 ND (5) 21.6 23.9 23.5 77.4 21.2

486 365 2140 ND (5) 272 302 287 811 272

ND (50) 130 150 ND (5) 20 22 20 91 17

320 1300 1800 ND (25) 250 270 250 1100 260

ND (20) 40.7 160 ND (20) 22.2 21.8 19.2 92.8 23.7

168 ND (100) 2560 ND (100) 284 277 248 1144 353

ND (50) 66 210 ND (5) 24 24 25 69 25

510 850 2400 ND (5) 290 300 290 860 300

AROMATICS MIXTURE VPH (µg/L) C5-C8 Aliphatics, Adjusted C9-C12 Aliphatics, Adjusted C9-C10 Aromatics Methyl tert-butyl ether Benzene Toluene Ethylbenzene Xylenes, mixture Naphthalene

300 700 200 70 5 1,000 700 5,000 140

34 230 190 ND (5) 26 27 25 111 23

NOTES AND ABBREVIATIONS: 1. Bold values indicate an exceedance of Method 1 (ALIPHATIC) criteria. 2. ND(2.5): Not detected; number in parentheses is the laboratory reporting limit. 3. VPH: Volatile Petroleum Hydrocarbons Haley & Aldrich, Inc.

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2011 VPH study analytical data results for samples spiked with aromatic hydrocarbons TABLE II SUMMARY OF WATER QUALITY DATA LABORATORY SAMPLE DESIGNATION PREPARATION DATE

F

F

G

MCP

HA-1 (OW)

HA-2 (OW)

HA-1 (OW)

HA-2 (OW) HA-1 (OW) HA-2 (OW) HA-1 (OW) HA-2 (OW)

G

H

H

J

Reportable

04-Aug-11

04-Aug-11

04-Aug-11

04-Aug-11

ND (50) 198

295 415

ND (50) 65

ND (500) 660

04-Aug-11 04-Aug-11 04-Aug-11

J 04-Aug-11

Concentration RCGW-1 AROMATICS MIXTURE VPH (µg/L) C5-C8 Aliphatics, Adjusted C9-C12 Aliphatics, Adjusted

300 700

ND (100) 180

620 1700

ND (50) ND (50)

374 243

C9-C10 Aromatics

200

196

330

170

1900

150

1600

189

1830

Methyl tert-butyl ether

70

ND (3)

ND (15)

ND (1)

ND (10)

ND (1)

ND (1)

ND (1)

ND (1)

Benzene

5

23.3

136

24

270

22

270

26.2

292

Toluene

1,000

23.6

88.1

24

280

22

270

26.1

292

700

23.9

95.7

23

270

22

260

26

287

5,000

69.4

277.5

117

1380

66

770

107.8

1174

140

19.7

158

24

290

22

270

21.1

271

Ethylbenzene Xylenes, mixture Naphthalene

NOTES AND ABBREVIATIONS: 1. Bold values indicate an exceedance of Method 1 (ALIPHATIC) criteria. 2. ND(2.5): Not detected; number in parentheses is the laboratory reporting limit. 3. VPH: Volatile Petroleum Hydrocarbons

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VPH study results for aromatic hydrocarbon-spiked samples • 2000 Study • Range of ADJUSTED C5-C8 aliphatics concentrations detected: • Not Detected to 34 µg/L in samples spiked at 24 µg/L and 168 to 510 µg/L in samples spiked at 300 µg/L • Range of ADJUSTED C9-C12 aliphatics concentrations detected: • 40.7 to 230 µg/L in sample spiked at 24 µg/L • 365 to 2,300 µg/L in sample spiked at 300 µg/L

• 2011 Study • Range of ADJUSTED C5-C8 aliphatics concentrations detected: • Not Detected in sample spiked at 24 µg/L and 295 to 620 µg/L in sample spiked at 300 µg/L • Range of ADJUSTED C9-C12 aliphatics concentrations detected: • 65 to 198 µg/L in sample spiked at 24 µg/L • 243 to 1,700 µg/L in sample spiked at 300 µg/L 32

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Example chromatogram for aromatic hydrocarbon-spiked sample

peaks highlighted by arrows suggest possible coelution of styrene with o-xylene 33

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Haloethane VPH study results summary • Haloethane study results confirm that common chlorinated volatile organic compounds (cVOCs) are reported as VPH aliphatic hydrocarbons • In general, approximately 1 mg/L total cVOCs may result in reported C5-C8 aliphatics that exceed one or more MassDEP Method 1 risk criteria • Chromatograms suggest that low boiling cVOCs do not interfere and that less common, higher boiling cVOCs elute in the C9-C12 range • By inference, the presence of many other non-target VOCs could result in false positive VPH results (e.g., methyl ethyl ketone) 34

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Aromatic VPH study results summary • Aromatic study results confirm that common aromatic volatile organic compounds are reported as VPH aliphatic hydrocarbons (remainder effect) • In general, approximately 2.7 mg/L total non-target aromatic VOCs may result in reported C5-C8 and C9-C12 aliphatics that exceed one or more MassDEP Method 1 risk criteria • By inference, the presence of other non-target VOCs could result in false positive VPH results (e.g., alkenes)

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Current case study • Concentrations of 1,2-dichloroethane in monitoring well in excess of regulatory criterion (>500,000 µg/L)

• VPH analysis also indicate C5-C8 aliphatics in excess of regulatory criterion (>175,000 µg/L)

• Data were CAM Compliant (have “Presumptive Certainty” per MassDEP) with acceptable QC; no nonconformances present

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Current case study - 8260 chromatogram xxxxxxxxxxx

source: CAM 8260 analysis of groundwater

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Current case study – VPH chromatogram (PID)

source: CAM VPH analysis of groundwater

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Current case study – VPH chromatogram (FID)

source: CAM VPH analysis of groundwater

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Case study outcome • Internal review of data indicate that the VPH C5-C8 aliphatic results are due to the presence of 1,2-dichloroethane • Laboratory reissued report; VPH C5-C8 aliphatics results were adjusted by subtracting the native sample Method 8260 result for 1,2-dichloroethane • revised VPH C5-C8 aliphatics result is appropriately ND

• All data adjustments documented and narrated

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Alternative VPH methodology draft • Current VPH methodology utilizes GC to differentiate the aromatic and aliphatic fractions by their differing responses to the FID and PID • compound identifications determined by GC retention time • non-petroleum compounds with the “right retention times” can be included

• New pending VPH methodology alternative based on GC/MS • similar to APH analysis • GC/MS VPH method should be capable of better distinguishing non-petroleum compounds

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Summary and Recommendations • VPH Method is a better method than TPH for characterizing petroleum hydrocarbons and thus estimating risk • Because VPH is a GC method: • Common chlorinated hydrocarbons, is present, will respond and be reported as VPH (C5-C8 aliphatics and/or C9-C12 aliphatics) • Aromatic hydrocarbons can “survive” the method adjustment and be reported in the “corrected” values as C5-C8 aliphatics and C9-C12 aliphatics

• Careful subtraction in the data can be performed to get a more accurate picture • One alternative is to request GC/MS analysis if offered by your lab…it can better resolve what constituents are actually petroleum-related 42

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Conclusions • Conducting solely VPH analysis may result in a “false positive” result for petroleum-related compounds • Current GC methods do not include a requirement to advise you of “qualitative” matters such as peak patterns • Common cVOCs or aromatics may trigger response actions for petroleum when “true” condition would be attributable to cVOCs or aromatics • Select analytical methods based on your understanding of site contaminants of concern • The potential for “false positive” results should also apply similarly to EPH analysis (e.g., phthalates) 43

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