Comparison of EPA 8260B to EPA TO-15

Pearl J PereiraSenior Scientist

IRIS EnvironmentalIrvine, California

949-724-8900http://www.irisenv.com/

IRIS EnvironmentalIRIS Environmental

DTSC Soil Gas Advisory ForumMarch 4, 2008

http://www.irisenv.com/

This presentation focuses on data quality challenges associated with differences in data sampling techniques and analytical methods

IRIS Environmental

Understanding the problem

IRIS Environmental

Active Oil Well

Potential Vapor Plume

Road

Not to scale

Abandoned Oil Wells

Sampling Program

A total of 209 soil gas samples were collected from 172 sample locations

IRIS Environmental

Difference in Installation and Sampling Techniques

IRIS Environmental

Collection: Syringes Summa Canisters with flow controllers

Method: On-Site Mobile Off-Site Fixed BasedLaboratory Laboratory

Analysis: EPA 8260B EPA TO-15

On-site Off-site

172 Soil Gas Sample Locations

Field Observations inconsistent with current advisory

No site-specific lithological information was collected prior to the soil gas investigation

IRIS Environmental

Three-stage wash and rinse decontamination of drilling rods and other re-usable components were NOT practiced

Sample locations were installed along busy street at onefoot below ground surface

No leak test or site-specific purge test was conducted

Sampling equipment was stored on and near petroleum/diesel generators prior to installation

Results

IRIS Environmental

Tracer compound was detected in three of the on-site samples at values ranging from 17 to 7,200 parts per billion by volume (ppbv)

Benzene was detected in blank samples by on-sitemobile laboratory at

Maximum Concentrations Comparison

0

500

1000

1500

2000

2500

3000

3500

1,1,1-

TRICH

LORO

ETHA

NE

1,1,2-

TRIC

HLOR

O-1,2

,2-TR

IFLUO

ROET

HAN

1,2,4-

TRIM

ETHY

LBEN

ZENE

1,2-D

ICHLO

ROET

HANE

1,3,5-

TRIM

ETHY

LBEN

ZENE

1,3-B

UTAD

IENE

2-BUT

ANON

E

2-HEX

ANON

EAC

ETON

E

4-ETH

YLTO

LUEN

E

4-MET

HYL-2

-PEN

TANO

NE (M

IBK)

BENZ

ENE

BROM

ODIC

HLOR

OMET

HANE

BROM

OMET

HANE

BUTA

NE

CARB

ON DI

SULF

IDE

CARB

ON TE

TRAC

HLOR

IDE

CHLO

ROFO

RM

CHLO

ROET

HANE

CHLO

ROME

THAN

E

CIS-

1,2-D

ICHLO

ROET

HENE

DICHL

OROD

IFLUO

ROME

THAN

EET

HANO

L

ETHY

LBEN

ZENE

HEPT

ANE

N-HE

XANE

M,P-X

YLEN

EMT

BE

METH

YLEN

E CHL

ORIDE

O-XY

LENE

PROP

YLEN

EST

YREN

EPC

E

TETR

AHYD

ROFU

RAN

TOLU

ENE

TCE

TRIC

HLOR

OFLU

OROM

ETHA

NE

TRIM

ETHY

L PEN

TANE

VINYL

ACET

ATE

VINYL

CHL

ORID

EM

axim

um C

once

ntra

tion

(ppb

(v/v

))

On-Site Off-Site

Acetone

Benzene

m,p-xylene

TolueneTCE

PropyleneStyrene PCE

Minimum Concentrations Comparison

0

5

10

15

20

25

30

35

40

1,1,1-

TRIC

HLOR

OETH

ANE

1,1,2-

TRIC

HLOR

O-1,2

,2-TR

IFLU

OROE

THAN

E

1,2,4-

TRIM

ETHY

LBEN

ZENE

1,2-D

ICHL

OROE

THAN

E

1,3,5-

TRIM

ETHY

LBEN

ZENE

1,3-B

UTAD

IENE

2-BU

TANO

NE

2-HE

XANO

NEAC

ETON

E

4-ET

HYLT

OLUE

NE

4-ME

THYL

-2-P

ENTA

NONE

(MIB

K)BE

NZEN

E

BROM

ODIC

HLOR

OMET

HANE

BROM

OMET

HANE

BUTA

NE

CARB

ON D

ISUL

FIDE

CARB

ON T

ETRA

CHLO

RIDE

CHLO

ROFO

RM

CHLO

ROET

HANE

CHLO

ROME

THAN

E

CIS-

1,2-D

ICHL

OROE

THEN

E

DICH

LORO

DIFL

UORO

METH

ANE

ETHA

NOL

ETHY

LBEN

ZENE

HEPT

ANE

N-HE

XANE

M,P-

XYLE

NEMT

BE

METH

YLEN

E CH

LORI

DEO-

XYLE

NE

PROP

YLEN

EST

YREN

EPC

E

TETR

AHYD

ROFU

RAN

TOLU

ENE

TCE

TRIC

HLOR

OFLU

OROM

ETHA

NE

TRIM

ETHY

L PEN

TANE

VINY

L ACE

TATE

VINY

L CHL

ORID

E

Min

imum

Con

cent

ratio

n (p

pb(v

/v))

On-Site Off-Site1,1,1-Trichloroethane

cis-1,2-dichloroethene vinyl acetate

Conclusion

Data quality objectives were not defined

IRIS Environmental

Recommended guidelines were not followed

Variability in analytical and sampling techniques did not produce reliable and defensible data sets.

Discussion

IRIS Environmental

How significant are confirmation samples?

Appropriate selection of sampling techniques and analytical methods as defined by data quality objectives is a MUST

Need for protocols to address discrepancies with data sets collected with different analytical techniques

This presentation focuses on data quality challenges associated with differences in data sampling techniques and analytical meResults Maximum Concentrations ComparisonConclusionDiscussion