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TO-15 or not TO-15?

TO-15 or not TO-15?. That is the question. James Picker, Ph.D. 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. Perceived (advertised?) Difference. OR. Actual difference. OR.

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TO-15 or not TO-15?

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

  2. 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

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

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

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

  6. 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

  7. Differences 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. Standards and Sample Preparation H&P Mobile GeoChemistry Escondido, CA

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

  9. 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

  10. 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

  11. 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

  12. 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

  13. Calibration RangeMDL to highest standardassumes 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

  14. Fail LevelsTCE @ 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

  15. Fail LevelsBenzene @ 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

  16. Project BL 4FEB05results in ug/L Average % Diff across all compounds = 38% H&P Mobile GeoChemistry Escondido, CA

  17. Project MC 1FEB05results in ppbv H&P Mobile GeoChemistry Escondido, CA

  18. 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

  19. 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

  20. H&P Mobile GeoChemistry Escondido, CA

  21. H&P Mobile GeoChemistry Escondido, CA

  22. 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

  23. James Picker, Ph.D.148 Vinewood Street Escondido, CA 92029 (800) 834-9888www.HandPmg.com

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