presented by Wayne Einfeld and Gary Brown Sandia National Laboratories

1. Technology Performance Characteristicsfor theOn-Site Measurementof Chlorinated Volatile Organic Compoundsin Groundwater presented by Wayne Einfeld and Gary Brown Sandia National Laboratories Albuquerque, New Mexico USA Eric Koglin United States Environmental Protection Agency Las Vegas, Nevada USA

2. Presentation Overview A US EPA Environmental Technology Verification test of field-portable water monitoring instruments is described. Test results are presented which include the features and performance characteristics of five different on-site instrumental analysis methods for the measurement of chlorinated VOCs in groundwater at contaminated sites.

3. Presentation Outline • Overview of ETV Program and the Site Characterization and Monitoring Technology Center • Technology Overviews • Verification Test Design • Verification Test Results • Summary and Conclusions

4. Environmental Technology Verification (ETV) Program • Established by EPA to verify the performance of innovative environmental technologies • Accelerates acceptance and use of improved, cost-effective technologies • Public and private partners to test technologies under EPA sponsorship and oversight • Six Centersincluding the Site Characterization and Monitoring Technologies Center (SCMT) • Site Characterization and Monitoring Technology Center has Sandia National Laboratories and Oak Ridge National Laboratory as verification testing partners

5. Site Characterization and Monitoring Technologies Center Our Technology Focus . . . Verify the performance of technologies that can be used for generating real-time data or information to support monitoring of human and ecosystem health, assessing real or potential exposure to environmental contaminants and hazards, for monitoring environmental conditions, and characterizing (physically and chemically) contaminated sites

6. SCMT Center Goals • Accelerate the use and acceptance of innovative environmental monitoring and characterization technologies • Rigorous, statistically-defensible testing under actual field conditions • Provide reliable, high-quality performance information • Leverage federal resources and expertise

7. What does Verification Mean? To establish or prove the truth of the performance of a technology under specific, predetermined criteria or protocols and adequate data quality assurance procedures.

8. SCMT Technology Areas • Field analytical technologies • Field portable X-Ray fluorescence spectrometers • Field portable gas chromatograph/mass spectrometers • Immunoassay kits • Field portable gas chromatographs • Fiber optic chemical sensors • Alpha detectors • Colorimetric test kits

9. SCMT Technology Areas cont’d • Decision support software systems • Physical characterization (e.g., geophysical methods, direct-push systems) • Soil, soil gas, groundwater, surface water, and sediment sampling methods • Technologies for assessing contaminated structures • Monitoring bioremediation and natural attenuation • Toxicity screening methods

10. Technology Verification Process Verification Test Planning Field Testing Data Collection and Validation Final Report & Verification Statement Report Preparation

11. Verification Test Plan Development Verification Test Plan Center Team

12. Verification Testing in the Field Verification Org. coordinates Vendors operate their instruments Testing at two sites or conditions “Blind” sample analysis QA audits during field tests

13. Technology Verification Report Contents • Verification Statement • Technology Description • Site and Design Description • Reference Laboratory Data Validation • Verification Test Results • Field Observations and Cost Summary • Technology Update

14. Verification of Field Analytical Techniquesfor the Measurement VOCs in Water • Goal: Verify field analytical techniques capable of detecting and quantifying chlorinated VOCs in water • Demonstration objectives: • Obtain performance information using quality control and field samples • Compare technology results with conventional laboratory results • Determine logistical requirements for technology use • Data used in this presentation is taken from from published ETV reports (www.epa.gov/etv)

15. Five Technologies Were Tested

16. Why use these technologies? • Faster, cheaper, better site screening and routine ground water monitoring • Quick-turnaround sampling and analysis enables on-site decisions and dynamic workplans • Less sample handling and paperwork • Reapplication of existing equipment

17. How might these technologies be used? • Field analytical support for direct push investigations • Preliminary groundwater screening at new or existing wells • Real-time monitoring for plume migration/barrier wall performance • Routine groundwater monitoring programs for known compounds at relatively high contamination levels (>10 ug/L) • Soil vapor analysis • Waste water outfall monitoring

18. Getting Sample to the Instrument Equilibrium Headspace - simple - less sensitive - HAPSITE, Voyager, Multi-gas Monitor Purge-and-Trap/Thermal Desorption - more complex - more sensitive - Scentograph Plus II, EST Model 4100

19. Equilibrium Headspace Henry’s Law At constant temperature: [VOC]gas __________ = Henry’s Constant [VOC]liq Henry’s Constant is compound-specific and is determined by the solubility of the compound in water Less soluble > Higher headspace concentration More soluble > Lower headspace concentration A gas sample is withdrawn from the headspace and analyzed by GC. The water concentration is calculated from the gas concentration using Henry’s Constant Gas Phase VOC Concentration Liquid Phase VOC Concentration

20. Dynamic Headspace (Purge-and-Trap) Step 1 Purge VOCs from solution and trap on sorbent Step 2 Heat the sorbent trap and sweep the VOCs off the sorbent with the carrier gas Purge Gas Helium or Nitrogen Carrier Gas 20

21. Gas Chromatography (GC) • Separates a mixture of compounds (usually organic) • Relies on differing solubilities of the analytes in an organic compound (stationary phase) lining the column wall • Detector at end of column allows separated compounds to be quantified • Retention time and detector response enable compound identification and quantification

22. Headspace/Gas Chromatography

23. Perkin-Elmer, Voyager Description: Field-portable GC with multiple columns and dual ECD and PID detectors, isothermal operation Size, Weight: Small, 48 pounds (with accessories) Sample handling:Completely manual Sample throughput:1-3 samples/hr Data processing: pre-programmedautomated methods, printed output Calibration: pre-deployment calibration, daily check standards Power: Battery or AC Cost: $24K Accessories: Carrier gases, optional PC, syringes, water bath Operator training: 1-2 hours for a chemical technician

24. Perkin-Elmer, Voyager

25. Electron Capture Detector A “standing current” is produced in the detector by the interaction of a radioactive electron source with the carrier gas. When electronegative compounds enter the detector they “capture” the electrons and cause a measurable change in the standing current.

26. Photoionization Detector • A UV lamp is used to irradiate a heated ionization chamber at the end of a GC column • The UV energy ionizes many organic molecules through a photoionization reaction: R + h = R+ + e- • The resulting ion current is sensed by an electrometer and is used to quantify the amount of material present Power Supply Electrometer From GC Column + – Exhaust UV Lamp Heated Ionization Chamber

27. Sentex Systems Inc., Scentograph Plus II Description: Field-portable, purge-and-trap GC with micro-argon ion and/or electron capture detector, isothermal or temperature program operation Size, Weight: Moderate, 80 pounds Sample handling:Completely automated Sample Throughput:2 samples/hour Data processing: pre-programmed automated methods, printed output not readily available Calibration: Daily three-point, daily check standards Power: Battery or AC Cost: $35K Accessories:Carrier gases, PC Operator training: Moderate

28. Sentex Systems Inc., Scentograph Plus II

29. Micro Argon Ion Detector • The detector contains a tritium foil that is used to irradiate the argon carrier gas • Some of the argon molecules become excited (metastable). • The metastable argon ionize the organics Ar + e– = Ar* Ar* + R = R+ + e– • The resulting ion current is sensed by an electrometer and is used to quantify the amount of organic material present Electrometer Argon carrier gas from GC column + – Exhaust Tritium Foil

30. Electronic Sensor Technology Inc., Model 4100 Description: Field-portable, purge-and-trap GC with surface acoustic wave detector Size, Weight: Moderate, 35 pounds Sample Handling: Partially automated Sample Throughput: 2-3 samples/hour Data processing: pre-programmed automated methods, printed output Calibration: pre-deployment 3-point calibration, periodic check standards, internal standard Power: Battery or AC Cost: $25K Accessories: Carrier gases, PC Operator training: 1 day for experienced chemical technician

31. Electronic Sensor Technology Inc., Model 4100

32. Surface Acoustic Wave Detector A surface acoustic wave (SAW) detector operates much like a quartz crystal detector. An AC voltage at the input transducer causes an acoustic wave to propagate across a crystal surface to the output transducer. Adding mass, such as an analyte from the end of a GC column, onto the detector surface causes a measurable change in the properties of the acoustic wave.

33. Inficon Inc., HAPSITE Description: Field-portable GC-MS and Headspace Sampling Accessory Size, Weight: Moderate, 75 pounds Sample Handling: Partially automated Sample Throughput: 2-3 samples per hour Data Processing: pre-programmed automated methods, printed output Calibration: pre-deployment multi-point, periodic check standard, internal and surrogate standards, daily MS tune check Power: Battery or AC Cost: $75-95K Accessories: Calibration and carrier gases, PC Operator training: 1 day of training for an experienced chemical technician

34. Inficon Inc., HAPSITE

35. GC-Mass Spectrometry An electron beam ionizes compounds exiting the GC column The quadrupole filter allows ions of specific mass to pass through the filter and strike the ion collector. The mass selectivity of the filter can be continuously scanned over a pre-determined range by changing the dc and rf settings of the filter. Quadrupole Mass Selective Detector

36. Innova AirTech Instruments Type 1312 Multi-gas Monitor Description: Field-portable, photoacoustic infrared bandpass spectrometer Size, Weight: Small, 30 pounds Sample Handling: Partially automated Sample Throughput: 1-2 samples/hr Data Processing: Automated method, manual recording of data necessary, no printed report Calibration: Factory calibration, no daily check standards Power: Battery or AC Cost: $28-35K Accessories: Headspace flask, stir plate, tubing Operator training: Several hours for a field technician

37. Innova AirTech Instruments Type 1312 Multi-gas Monitor

38. Photoacoustic Spectroscopy Chopped (intermittent) bandpass-filtered infrared radiation is passed through a cell containing the gases of interest. The target gases absorb the radiation. The absorption is accompanied by a rise and fall in temperature (pressure) in the cell at the chopping frequency. This pressure cycle or acoustic signal is detected by two sensitive microphones. The intensity of the pressure cycle is related to the target gas concentration.

39. Verification Test Design Elements • Different Environmental Conditions • Testing at two contaminated sites with groundwater wells (Savannah River, SC and McClellan AFB, CA) • Historical sampling data used to select GW wells • A Blend of Field and QA Samples • Performance evaluation (PE), 42 samples per site • Groundwater (GW), 33 samples per site • Blank samples, 8 per site • Reference Laboratory Analyses • Splits of all samples analyzed by an off-site reference laboratory • US EPA Method 8260 (Purge-and-trap GC-MS)

40. Verification Test Design Elements cont’d • Multiple VOC Compounds Participating technologies were not calibrated for all these compounds

41. Verification Test Design Elements cont’d • A Wide Concentration Range of Compounds • PE Samples: 10 µg/L to >1000 µg/L • GW Samples: 5 µg/L to > 1000 µg/L • Blind Replicate Samples • Triple or quadruplicate splits of all GW and PE samples • for determination of instrument precision

42. A Challenging Test Sample Matrix • 65 environmental groundwater samples from both sites • 84 performance evaluation (PE) water samples mixed and distributed onsite • 8 blank samples • ~160 samples analyzed per technology over ~ 8 days • Over 9000 individual compound analyses! Groundwater PE + Blanks

43. Field Sample Preparation • PE Samples • Performance Evaluation samples were mixed in a 10-L carboy in an onsite mobile laboratory and then dispensed into 40-mL VOA vials • Each of the five technologies and reference lab were given 4 replicates from all PE mixtures GW Samples • 10 liters of groundwater was sampled into a glass carboy from various monitoring wells with downhole electric pumps • Carboy contents were mixed and then dispensed into 40-mL VOA vials at the wellhead. Replicate samples were distributed to all participants and the reference laboratory

44. Sample Distribution HAPSITE PE Samples VOYAGER  Model 4100 GW Samples Scentograph Plus II  Multi-gas Monitor Blank Samples Reference Lab Each sample delivered in triplicate or quadruplicate

45. Definition of Terms Precision Relative standard deviation from replicate samples Accuracy Average percent recovery of a known test sample or absolute percent difference from a known Comparability Percent difference of results relative to reference laboratory results Detection Limit Method Detection Limit or Practical Quantitation Limit SampleSamples per hour Throughput False Positive Frequency that detects are reported for blank samples False Negative Frequency that no-detects are reported for compounds at or near the 5 ug/L regulatory limit

46. Key Instrument Performance Parameters in this Test • Accuracy - percent recovery • Precision - relative standard deviation • Comparability to reference - absolute percent difference • False positive/negative - at blank and 10 ug/L conc. levels • Sample throughput - samples per hour • Versatility - number of compounds detected • Ease of use - through field observation • Operator training requirements -through field observation

47. ETV doesn’t compare technologies • In a policy of fairness and objectivity, ETV doesn’t pick technology winners and losers • Technologies are varied and their application is usually site- and application-specific • The site user is best-suited to match site needs with technology capabilities • Side-by-side comparisons, if required, are left to the user ??? Brand Y Brand X

48. How the results are presented • Presentation by instrument • Performance Characteristics • False +/- • Accuracy • Precision • Comparison with Reference Lab • Summarized results are necessary (lots of data in reports!) • Performance for TCE and PCE is emphasized Technology Performance Results

49. Perkin Elmer Voyager False +/- False positive rate in 16 blanks: 19% False negatives for SRS site (10 Samples at 10 g/L): Compound False Negative Rate (%) 1,1-Dichloroethene 0 Dichloromethane 0 Chloroform 100 Carbon tetrachloride 0 1,2-Dichloropropane 80 Trichloroethene0 1,1,2-Trichloroethane 100 Dibromochloromethane 90 Tetrachloroethene 0 Chlorobenzene 0 1,1-Dichloroethane No calibration 1,2-Dichlorobenzene No calibration

50. Voyager Summary Precision Combined data from PE samples at both sites ** Voyager did not detect PCE in 7 of 8 sets