Robin & Blayne, PVI Workshop 25th Tanks Conf Phx, 9-13-15

Robin V. Davis, P.G. Project Manager

Utah Department of Environmental Quality Leaking Underground Storage Tanks

[email protected] 801-536-4177

Petroleum Vapor Intrusion Workshop Sunday September 13, 2015

1:00 pm – 5:00 pm

Recommended Field and Analytical Practices for Assessing the

Authors Blayne Hartman, Ph.D.

HARTMAN ENVIRONMENTAL

GEOSCIENCE www.hartmaneg.com

858-204-6170

25th National Tanks Conference Phoenix, Arizona

Petroleum Vapor Intrusion Pathway

2

PVI Investigations Are Very Intrusive

Cutting up carpet

Day-drinking resident

State Project Manager

Wild Turkey

Children & Toys

Assistant State

Project Manager

3

ITRC Guides

Soil Vapor Sampling

Technical Toolkit

Version 1.4

This work was funded by Chevron Environmental Management Company and performed by Chevron Energy Technology

Company, Health, Environment and Safety Group, Environmental Unit.

Copyright© 2005 Chevron Energy Technology Company. All Rights Reserved. This report and its appendices are intended

to be used by those conducting work for Chevron Environmental Management Company and Chevron Corporation

Brian M. Davis, Lead Hydrogeologist

Environmental Unit

Health, Environment and Safety Group

Chevron Energy Technology Company

Richmond, California, USA

September 7, 2005

Difference in Methods of

Installing

Nested Multi-Depth

Vapor Points

Best Practice Drill One Boring per Each

Multi-Depth Vapor Point Completion

6-inch Stainless Steel Screens for Each

Vapor Point Completion

Short PVC Lengths Protect Vapor Tubing

Courtesy of Direct Push Services, Highland, Utah

Collect Vapor Samples in <1-Liter Summa Canisters

Highest Quality Completion, Highest Quality Data

v

v

Fee

t B

elo

w G

rad

e

0

15

10

5

v

v

v LNAPL

Sand Pack

Drill 1 boring per vapor point completion Hydrate all bentonite layers thoroughly Bentonite crumbles only in small lifts around sand pack

6-inch Stainless Steel Screen

Nylon Tubing

Bentonite Chips

Bentonite Crumbles

Cement

Fee

t B

elo

w G

rad

e

0

15

10

5

v LNAPL

Clayey Silt

Silt

Sand Pack

6-inch Stainless Steel Screen

Nylon Tubing

Bentonite Crumbles

Cement

NOT ADVISED 1 Boring for Multiple Vapor Point Completions

v

v

High Potential for Leaks and Non-Representative Samples: • Full hydration of bentonite in thick lifts is difficult to achieve

• High potential for tubing to bend, tangle and kink

• Big pore spaces develop and form preferential pathways

Example of Bad Vapor Point Installation

Deepest point set followed by shallower points, separated by thick lifts of bentonite crumbles

All 3 Vapor Points Set in Same Boring

Bentonite Hydration at End of Multi-Depth Vapor Well Completion

UNADVISED: Full Hydration & Seal Not Likely

Bentonite Chips

Vapor Screen

Bentonite Crumbles

Bentonite Crumbles

Bentonite Chips

Sand Pack

A

B C

NOT ADVISED

Bentonite Crumbles

Bentonite Crumbles Throughout = HUGE Pore Spaces Due to Incomplete Hydration

RECOMMENDED PRACTICE • Thin lifts of crumbles

only above and below sand pack

• Bentonite chips for thick layers

• Hydrate each lift slowly & thoroughly

Examples of Vapor Point Completion Integrity

Data Anomalies due to

Improper Completions

and

Purging and Sampling Practices

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E+08

0 5 10 15 20 25

Be

nze

ne

Va

po

r C

on

ce

ntr

atio

ns,

ug

/m3

Oxygen Soil Gas %

Small UST/AST & Large Industrial Sites

Paired Measurements of Benzene Vapor & Oxygen in Soil…

Oxygen vs Benzene for Dissolved & LNAPL Sources

Anomalies represent small data population in database (4%-6%)

No effect on overall observation of biodegradation

No effect on screening criteria

Anomalies

1.E+00 1.E+02 1.E+04 1.E+06 1.E+08

0

2

4

6

8

10

0 5 10 15 20

Benzene (ug/m3)

O2 & CO2 (% V/V)

Huntington Beach, CA HB-3 (Ririe, et al 2002)

O2%

CO2%

Data Anomalies

1.E+00 1.E+02 1.E+04 1.E+06 1.E+08

0

5

10

15

20

0 5 10 15 20

Benzene (ug/m3)

De

pth

be

low

gra

de

(fe

et)

O2 & CO2 (% v/v)

Hal’s UT VW-10 (UDEQ 9/1/09)

Oxygen

Carbon Dioxide

Benzene

Anomalies

ANOMALOUS DATA SIGNATURE

Co-existing high concentrations hydrocarbon, high oxygen, low CO2

AEROBIC BIODEGRADATION SIGNATURE

High concentrations of hydrocarbon, low oxygen, high CO2

0

5

10

15

20

0 5 10 15 20

De

pth

be

low

gra

de

(fe

et)

2006-2014 Oxygen

Over Time

O2 4/14/06 fixed lab



O2 9/1/09 fixed lab

O2 6/24/14 0.5 min purge (0.1L)(Sweeney field-measured)O2 6/24/14 2-min purge (0.4 L)(Sweeney field-measured)

O2 %

• 2014 high-purge data corresponds to 2009 high-volume sample data

• Over-purging/large sample volume= non-representative soil gas samples

1.E+00 1.E+02 1.E+04 1.E+06 1.E+08

0

5

10

15

20

0 5 10 15 20

Benzene (ug/m3)

Dep

th b

elo

w g

rad

e (

fee

t)

O2 & CO2 (% v/v)

VW-7 9/1/09

Oxygen

Carbon Dioxide

Benzene

TPH-gro

Anomalies

2009

Vapor Samples

6-L Containers

Hal’s Chevron

VW-7

High-purge, over-purging

Sampling with large containers (e.g. 6-L Summas)

Improper sample point completion

How Anomalies Happen

Results of Anomalous Data Drawing vapors from non-representative areas

Non-representative vapor samples exhibit:

• High concentrations of hydrocarbons and oxygen

• High hydrocarbon concentrations can be diluted due

to short-circuiting with uncontaminated zones

• Uncontaminated zones exhibiting high hydrocarbons

v

v

Fee

t B

elo

w G

rad

e

0

15

10

5

v

v

v LNAPL

Clayey Silt

Silt

3 ft Tubing Volume= 0.017 L

7 ft Tubing Volume = 0.037 L



Recommended Purging and Sampling Practice, Step 1:

• Purge 1 tubing volume

v

v

Fee

t B

elo

w G

rad

e

0

15

10

5

v

v

v LNAPL

Clayey Silt

Silt

3 ft Tubing+Sand Pack = 0.511 L





• Purge 1 sand pack volume

v

v

Fee

t B

elo

w G

rad

e

0

15

10

5

v

v

v LNAPL

Clayey Silt

Silt

3 ft Tubing+Sand Pack+1L Container= 1.511 L

7 ft Tubing+Sand Pack+1L Container = 1.531 L




• Capture vapor sample in <1-Liter Container

v

v

Fee

t B

elo

w G

rad

e

0

15

10

5

v

v

v LNAPL

Clayey Silt

Silt 11 ft Tubing+Sand Pack+6L Container = 7.36 L

15 ft Tubing+Sand Pack+L Container = 7.37 L



• Purging and sampling excessive volumes results in vapors being drawn from

non-representative areas

• Non-representative vapor samples exhibit:

High concentrations of hydrocarbons and oxygen in the same sample

High hydrocarbon concentrations can be diluted due to short-circuiting with uncontaminated zones

Uncontaminated zones exhibiting high hydrocarbons

Soil Gas Temporal Study – EPA-ORD

Probe A3 (TCE - Normalized)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

13

:50

:09

10

:50

:26

7:5

0:4

4

4:5

1:0

4

1:5

1:4

3

22

:53

:46

5:4

3:2

9

2:4

3:4

7

23

:44

:04

20

:44

:22

17

:44

:39

14

:44

:57

11

:45

:15

8:4

5:3

2

16

:02

:01

13

:02

:18

10

:02

:36

7:0

2:5

5

4:0

3:1

2

1:4

3:5

6

22

:44

:15

7:0

6:4

1

4:0

6:5

9

1:0

7:1

9

22

:07

:58

19

:11

:25

Time (3/16/07 to 4/10/07)

No

rma

lize

d C

on

ce

ntr

ati

on

Probe A3-3' (Port 9)



Soil Gas Temporal Study, EPA-ORD

3’ bgs

8’ bgs

15’ bgs

• >500 points per probe collected once per hour over 4 week period

• Soil gas concentrations varied by <10% even for probes only 3 feet

below the surface.

METHODS TO ASSESS VI

• Indoor Air Sampling

• Groundwater Sampling

• Soil Phase Sampling

• Predictive Modeling

• Measure Flux Directly

• Soil Gas Sampling

• Supplemental Tools/Data

GENERAL APPROACH FOR ASSESSING VI

•Indoor Air • Always find something

• Multiple sampling rounds

•Groundwater and Soil Data – Typically over-predicts risk

•Soil Gas Data

– Best Data to Collect for PVI Assessment

PVI-SPECIFIC SAMPLING ISSUES

• Soil Gas VOC Analysis • Benzene, ethylbenzene & naphthalene

• TPH??

• Might Need to Sample <5’ bgs • If samples >5’ bgs exceed allowable levels

• How to know? On-site analysis best

• If not, collect samples anyway

• Oxygen and Carbon Dioxide Data demonstrate biodegradation

Ingredients for Effective VI Assessments

• Investigatory Approach

• Determine Correct Screening Levels

• Sample & Analyze Properly

• Know & Use Supplemental Tools

• Demonstrating Bioattenuation

The Most Important Ingredient

• Experience:

– Consultant

– Collector – done soil gas before?

– Lab – certified for methods?

– Regulator

– Public

– YOU!

What level person is going in the field?

Most Common VI Bloopers

• Unit Confusion

– Assuming mg/L equivalent to ppmv

– Assuming ug/m3 equivalent to ppbv

• Screening Levels

– Comparing to generic screening levels

– Not calculating correct levels

• Sampling & Analysis Errors

– Program design: soil gas? GW? SS? IA?

– Using wrong hardware

– Using wrong analysis

Units: ppmv

Incorrect Units

Wrong Screening Values

It Won’t Happen To Me …

RLs Not Low Enough

Uncertified Lab

All deployed & retrieved at exact same minute!

All final vacuums at 0

It Won’t Happen To Me #2…

PASSIVE IA COLLECTORS

Longer Collection Times Increases Odds of False Positives

GOT A LIFE?

Longer Collection Times = False Positives

SHAMPOO & CONDITIONER

According to European and Canadian reports, carcinogens are in almost every brand

Compound Shampoo Conditioner Cancer

(µg/m3)

Noncancer

(µg/m3)

1,4-Dioxane 87 - 0.490 31

Chloromethane 170 88 n/a 94

Ethyl acetate 6,500 120 n/a 73

Isopropylbenzene - 280,000 n/a 420

(C9-C12) Aliphatics 11,000 32,000 0.54 1000

SODA

Interesting Fact: It is a well studied fact that Benzene is in soda pop (combination of a benzoate preservative and citric acid, especially in warm/light conditions)

Compound Soda Pop Cancer

(µg/m3)

Noncancer

(µg/m3)

(C5-C8) Aliphatics 260 13 630

(C9-C10) Aromatics 1,000 n/a 3.1

(C9-C12) Aliphatics 16,000 0.54 100

SILLY STRING

UDEQ 1st Floor, 6-L Summa Outside Boss’s Office

Indoor Air Data, Utah DEQ Building, 4-30-15 ug/m3

Compound

C-181

1st Floor

outside

boss's office

DERR

C-182

3rd Floor

inside

boss's office

DDW

EPA VISL

Commercial

Indoor Air (TR 10-06,

GW temp. 55 F)

Benzene 0.406 0.415 1.6

Toluene 6.86 1.93 22,000

Ethylbenzene 0.621 0.191 4.9c, 1482nc

Xylenes 1.97 0.895 440

Naphthalene 0.572 <1.05 0.36c, 4.39nc

MTBE < 0.072 <0.072 47c, 4380nc

Tetrachloroethene 0.203 <0.136 47

Trichloroethene < 0.107 <0.107 3.0

Trichlorofluoromethane 1.71 1.70 3100

Chlorodifluoromethane 1.70 1.76 220,000

Dichlororodifluoromethane 1.29 1.58 440

Chloromethane 1.38 1.36 390

1,2-Dibromoethane (EDB) < 1.54 <0.154 0.02

1,2-Dichloroethane (DCA, EDC) 0.162 0.142 0.47

Methanol 47.3 77.1 88,000

Ethyl Alcohol (Ethanol) 68.0 70.3 none

iso-Propyl Alcohol (Isopropanol) 5.8 9.88 880

Acetone 21.5 24.9 3100

2-Butanone 1.63 4.75 none

Methylene Chloride 2.89 <1.74 1200

Butane C4 1.66 1.63 none

Pentane C5 5.55 3.51 4400

Decane C10 3.03 <1.16 none

Undecane C11 2.72 <1.28 none

Dodecane C12 4.97 <1.39 none

Thank You

Documents

Robin & Blayne, PVI Workshop 25th Tanks Conf Phx, 9-13-15