H&P Mobile GeoChemistry Escondido, CA TO-15 or not TO-15? That is the question. James Picker, Ph.D. H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA Objective Compare/Contrast EPA Method 8260B vs. EPA Method TO-15/TO-14A Used for the analysis of VOCs in soil vapor (gas) to measure health risk H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA Perceived (advertised?) Difference OR H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA Actual difference OR H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA Summary EPA 8260 vs. TO-15/14A Data Reduction GC/MS System Sample Preparation SAME IDENTICAL SLIGHTLY DIFFERENT H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA 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 H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA Differences Standards and Sample Preparation EPA 8260B (modified) *Standards in liquid (MeOH)* Purge and trap Purged from headspace and H2O using He or dry purging Water management Desorption direct to GC/MS EPA TO-15/14A *Standards in Air (N2)* Vacuum (or Pressure) flow and Trap pulled from cylinder, using pump or pressure Desorption to cryofocus or directly to GC/MS. H&P Mobile GeoChemistry Escondido, CA

Standards in Water or Air - H&P Mobile GeoChemistry Escondido, CA

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, H&P Mobile GeoChemistry Escondido, CA

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 H&P Mobile GeoChemistry Escondido, CA

Compounds Analyzed with a high bias by EPA 8260 versus TO-15 Ethanol, TBA 1,4 Dioxane Acetone & other ketones Any water soluble low volatility compound H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA 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) H&P Mobile GeoChemistry Escondido, CA

Calibration Range MDL to highest standard assumes 20 cc sample Normal Range 8260 SCAN Extended by dilution 8260 SIM TO-15/14A SCAN TO-15/14A SIM 10-2 10-1 1 10 102 103 104 105 ug/m3 H&P Mobile GeoChemistry Escondido, CA

Fail Levels TCE @ subslab TCE @ 5’bgs EPA R9 CA-EPA 8260 SCAN 8260 SIM TO-15/14A SCAN TO-15/14A SIM 10-2 10-1 1 10 102 103 104 105 ug/m3 H&P Mobile GeoChemistry Escondido, CA

Fail Levels Benzene @ subslab Benzene @ 5’bgs CA EPA EPA R9 8260 SCAN 8260 SIM TO-15/14A SCAN TO-15/14A SIM 10-2 10-1 1 10 102 103 104 105 ug/m3 H&P Mobile GeoChemistry Escondido, CA

Project BL 4FEB05 results in ug/L Sample TO-15 PCE 8260 TCE c12DCE t12DCE F-113 SV1 128 88 42 31 <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 SV4 541 330 75 60 SV5 169 110 70 65 1.5 3.1 SV6 234 150 138 3.6 3.2 4.8 4.1 SV7 108 54 25 17 2.1 SV8 250 120 74 4.7 3.5 9.9 AVG %Diff. 52 28 13 19 Average % Diff across all compounds = 38% H&P Mobile GeoChemistry Escondido, CA

Project MC 1FEB05 results in ppbv Sample TO-15 PCE 8260 TCE c12DCE 111TCA F-113 SG1 190 250 <16 <25 32 NA SG3 59 83 110 93 40 36 SG8 <14 64 540 370 SG12 1300 910 91 65 360 261 SG13 29 98 81 28 <20 H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA Conclusions For most vapor intrusion compounds of interest, methods yield identical results For more water soluble compounds 8260 is within factor of 2. Fine for VI calculations A few compounds may require TO method. Some compounds may require 8260 method On-site analysis assists in decision making, regulatory QA requirements and assurance of tracer compound integrity H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA 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 Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA

H&P Mobile GeoChemistry Escondido, CA

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 Street Escondido, CA 92029 (800) 834-9888 www.HandPmg.com