h&p mobile geochemistry escondido, ca to-15 or not to-15? james picker, ph.d. that is the...

H&P Mobile GeoChemistry Escondido, CA

TO-15 or not TO-15?

James Picker, Ph.D.

That is the question.


Objective

Used for the analysis of VOCs in soil vapor (gas) to measure health risk

Compare/Contrast

EPA Method 8260B vs. EPA Method TO-15/TO-14A


OR

Perceived (advertised?) Difference


OR

Actual difference


Summary EPA 8260 vs. TO-15/14A

SAME IDENTICAL

Data Reduction GC/MS System Sample Preparation

SLIGHTLY DIFFERENT


Similarities

GC/MS Method (SCAN or SIM)

GC with FSCC (20-60m X 0.18-0.32mm id)

LRMS (quadrupole, ion trap, TOF)

*Concentration of compounds on multiadsorbent trap*

Uses Internal Standards/Surrogate(s) for accuracy/QC

Multipoint Calibration ICAL, linearity checks, Daily CCV

Varying sample size permitted

Quant by RFs


Differences Standards and Sample Preparation

EPA 8260B (modified)

*Standards in liquid (MeOH)*

Purge and trapPurged from headspace and H2O

using He or dry purgingWater managementDesorption direct to GC/MS

EPA TO-15/14A

*Standards in Air (N2)*

Vacuum (or Pressure) flow and Trappulled from cylinder, using pump or pressure

Desorption to cryofocus or directly to GC/MS.


Standards in Water or Air

-


Compounds Analyzed equally well by EPA 8260 or TO-15

• BTEX, Trimethylbenzenes, Freons

• PCE, TCE, vinyl chloride, DCEs, 1,2- DCPE, 1,1,1,2- TCA

• 1,1,1-TCA,


Compounds Analyzed with a slight high bias by EPA 8260 versus TO-15

• MTBE, other oxygenates• 1,1,2,2-TCA, 1,2- DCA, 1,1,2-TCA• Naphthalene• rest of common 8260 list


Compounds Analyzed with a high bias by EPA 8260 versus TO-15

Ethanol, TBA1,4 DioxaneAcetone & other ketonesAny water soluble low volatility compound


Differences II Calibration and Range

EPA 8260B (modified)

“Typical” Calibration 500 – 50000 ug/m3 (160-16000 ppbv for benzene)

MDLs 100 ug/m3 (31 ppbv benzene) For 8260 SIM 10 ug/m3 (3 ppbv benzene

EPA TO-15/14A

“Typical” Calibration 3-120 ug/m3 benzene (1-40 ppbv)

MDLs 0.3 ug/m3 benzene( 0.1ppbv)

For TO-15 SIM 0.03 ug/m3 benzene (0.01ppbv)


Calibration RangeMDL to highest standardassumes 20 cc sample

10-2 10-1 1 10 102 103 104 105

ug/m3

TO-15/14A SIM

8260 SCAN

TO-15/14A SCAN

8260 SIM

Normal Range

Extended by dilution


Fail LevelsTCE @ subslab TCE @ 5’bgs

10-2 10-1 1 10 102 103 104 105

ug/m3

TO-15/14A SIM

8260 SCAN

TO-15/14A SCAN

8260 SIM

EPA R9 CA-EPA


10-2 10-1 1 10 102 103 104 105

ug/m3

TO-15/14A SIM

8260 SCAN

TO-15/14A SCAN

8260 SIM

Fail LevelsBenzene @ subslab Benzene @ 5’bgs

CA EPA EPA R9


Project BL 4FEB05results in ug/L

Sample TO-15

PCE

8260

PCE

TO-15

TCE

8260

TCE

TO-15

c12DCE

8260

c12DCE

TO-15

t12DCE

8260

t12DCE

TO-15

F-113

8260

F-113

SV1 128 88 42 31 <1 <1 <1 <1 1.6 1.1

SV2 399 280 134 100 4.4 3.7 1.7 1.4 3.4 2.7

SV3 95 46 40 31 <1 <1 <1 <1 1.7 1.6

SV4 541 330 75 60 <1 <1 <1 <1 <1 <1

SV5 169 110 70 65 1.5 1.7 <1 <1 3.4 3.1

SV6 234 150 138 110 3.6 3.2 <1 <1 4.8 4.1

SV7 108 54 25 17 <1 <1 <1 <1 3.1 2.1

SV8 250 120 120 74 4.7 3.5 <1 <1 9.9 4.8

AVG

%Diff.52 28 13 19 28

Average % Diff across all compounds = 38%


Project MC 1FEB05results in ppbv

Sample TO-15

PCE

8260

PCE

TO-15

TCE

8260

TCE

TO-15

c12DCE

8260

c12DCE

TO-15

111TCA

8260

111TCA

TO-15

F-113

8260

F-113

SG1 190 250 <16 <25 32 <25 <16 <25 NA NA

SG3 59 83 110 93 <16 <25 40 36 NA NA

SG8 <16 <14 <16 64 <16 <25 540 370 NA NA

SG12 <16 <14 1300 910 91 65 360 261 NA NA

SG13 29 <14 98 81 <16 <25 28 <20 NA NA


Conclusions

1. For most vapor intrusion compounds of interest, methods yield identical results

2. For more water soluble compounds 8260 is within factor of 2. Fine for VI calculations

3. A few compounds may require TO method. Some compounds may require 8260 method

4. On-site analysis assists in decision making, regulatory QA requirements and assurance of tracer compound integrity


Recommendations

Choose either or a combination of methods, depending on compounds and DLs required

Select on-site analysis for decision making, regulatory QA requirements (assurance of tracer compound integrity, purge volume testing, etc.)

Do onsite TO-15 where levels are low Do onsite 8260 where levels are moderate to high Follow with offsite TO-15 for Quality Assurance

H&P’s Solutions

Option 1 – Where 8260B Meets Project DQOs:On-site, full QC 8260B fulfilling DTSC/LA-RWQCB requirements with off-site TO-15 confirmation on a sub-set of samples.

Option 2 – Where TO-14/15 is required to meet Project DQOs:On-site screening-level 8260B of all samples with of-site analysis of ALL samples by TO-15.

Option 3 – For larger projects with lower DLs:On site TO-15

All Options:

Fulfill all DTSC soil gas advisory requirements

Allow on-site analysis for leak/tracer compound test

Guarantee sample integrity

Provide real-time data for real-time decisions

James Picker, Ph.D.148 Vinewood StreetEscondido, CA 92029

(800) 834-9888www.HandPmg.com

h&p mobile geochemistry escondido, ca to-15 or not to-15? james picker, ph.d. that is the...

Documents

sim epa r9 caepa slide

ca standards

ca compounds

ppbv slide

ca summary epa

ca objective

air slide

ppbv benzene epa