Advances in field sampling:

Transcription

1 Advances in field sampling: No-flow versus Low-flow SEPTEMBER 215

2 OVERVIEW 2 Low-flow samplers used as standard for GMEs No-flow samplers Also known as non-purge, passive, grab, snap, discrete interval samplers 3 sizes of no-flow samplers used: -.6L & 2L (completed) - 1L (in progress) Trial at 2 sites with the same geology in western Melbourne Comparative results Stratification Data quality Technical acceptance Commercial benefits Geoscience Australia 29

3 NO-FLOW COMPARED TO LOW-FLOW Low-flow (Micropurge ) Advantages Purge parameter stabilisation Multi-task during sampling Limitations Slow sampling Multiple equipment requirements Waste water disposal Under reports VOCs (Britt et al 21) No-flow (HydraSleeve ) Advantages Limited equipment Simple set up (pre-sampling set up) Quick sampling No waste water disposal Limitations No purge single set of water quality parameter readings Large volume samplers

4 HYDRASLEEVE TRIALS WESTERN MELBOURNE SITES 4 Site A Current major hazard facility Geology Fractured basaltic rock Aquifer Shallow 8-1mBGL, SegC GME analytical suite: TRH, BTEX, naphthalene, lead Site B Former major hazard facility Geology Fractured basaltic rock Aquifer Shallow 8-1mBGL, SegC GME analytical suite: TRH, BTEX, naphthalene, SVOCs, VOCs, phenols, metals, cyanide, inorganics Comparative trial conducted May 213 x1 locations,.6l HydraSleeves Comparative trial conducted December 214 x1 locations, 2L HydraSleeves Comparative trial conducted September 215 x1 locations, 1L HydraSleeves

5 5 LOW-FLOW SAMPLER MICROPURGE Lower the pump to required sample depth Purge water until stabilised Record water levels during pumping Record field parameters (water quality meter) Fill sample bottles: Site A 1 locations Site B 1 locations Set up.25hr/well Sampling time required.75hr/well

6 NO-FLOW SAMPLER HYDRASLEEVE 6 Lower the weighted HydraSleeve to below required sample depth. Allow water column to equilibrate max 1hr for.6l to 1L (3 days for 2L) samplers Retrieve HydraSleeve, hang and fill sample bottles (straw): Site A 1 locations -.6L samplers Site B 1 locations 2L samplers Site B 1 locations 1L samplers (in progress) Subsample transferred to purge cell for field parameters Prep.2hr/well Sampling time required.5hr/well

7 COMPARISON OF RESULTS 7 2 HydraSleeve sampling concentration (µg/l) 1 What does the trend line suggest? Perfect relationship 1 Micropurge sampling concentration (µg/l) 2

8 COMPARISON OF RESULTS 8 2 HydraSleeve sampling concentration (µg/l) 1 HydraSleeve results higher than Micropurge 1 Perfect relationship Micropurge sampling concentration (µg/l) 2

9 9 COMPARISON OF RESULTS 2 HydraSleeve sampling concentration (µg/l) 1 Perfect relationship Micropurge results higher than HydraSleeve 1 2 Micropurge sampling concentration (µg/l)

10 BENZENE 1 HydraSleeve sampling concentration (µg/l) 4, 35, 3, 25, 2, 15, 1, 5, R 2 values >.9 indicate low degree of scatter & higher confidence that slope is meaningful (Parsons 25) Trend line y = x R² =.9445 Perfect relationship line 5, 1, 15, 2, 25, 3, 35, 4, Micropurge sampling concentration (µg/l) Site A and Site B Excellent relationship - HydraSleeve more conservative

11 BTEX 11 HydraSleeve sampling concentration (µg/l) 4, 35, 3, 25, 2, 15, 1, 5, y = x R² =.9445 Excellent relationship - HydraSleeve more conservative 5, 1, 15, 2, 25, 3, 35, 4, Micropurge sampling concentration (µg/l)

12 TOTAL RECOVERABLE HYDROCARBONS 12 HydraSleeve sampling concentration (µg/l) 6, 5, 4, 3, 2, 1, TRH C6-C1 y = x R² = , 2, 3, 4, 5, 6, 6, Excellent relationships - HydraSleeve more conservative 5, 4, 3, 2, 1, TRH C1-C4 y = x R² = , 2, 3, 4, 5, 6, Micropurge sampling concentration (µg/l)

13 INORGANICS SULFATE 13 HydraSleeve sampling concentration (mg/l) 4,5 4, 3,5 3, 2,5 2, 1,5 1, 5 y =.9861x R² =.9975 Excellent relationship 1, 2, 3, 4, Micropurge sampling concentration (mg/l) Site B data only

14 INORGANICS TDS 14 1, HydraSleeve sampling concentration (mg/l) 9, 8, 7, 6, 5, 4, 3, 2, 1, Excellent relationship y =.9854x R² = , 4, 6, 8, 1, Micropurge sampling concentration (mg/l)

15 METALS MANGANESE 15 HydraSleeve sampling concentration (µg/l) 4,5 4, 3,5 3, 2,5 2, 1,5 1, 5 y =.985x R² =.9619 Excellent relationship - HydraSleeve less conservative 5 1, 1,5 2, 2,5 3, 3,5 4, 4,5 Micropurge sampling concentration (µg/l)

16 PHENOLICS 16 HydraSleeve (µg/l) Phenolics (group) y =.8562x R² = Micropurge (µg/l) Excellent relationship - HydraSleeve less conservative HydraSleeve (µg/l) 1, Pentachlorophenol Poor relationship y =.6134x R² = , Micropurge (µg/l) R 2 values <.9 indicate greater degree of scatter & low confidence that slope is meaningful (Parsons 25)

17 CORRELATION SUMMARY Summary of correlation HydraSleeve results higher Micropurge results higher Gradient (y) Majority of analytes have good correlation Coefficient of determination (R 2 ) 9% confidence

18 18 SUMMARY Summary of correlation HydraSleeve results higher Micropurge results higher Gradient (y) Ionic balance.6.4 Pentachlorophenol Vanadium & nickel Coefficient of determination (R 2 ) 9% confidence

19 CORRELATION CRITERIA 19 2 HydraSleeve sampling concentration (µg/l) 1 Trend line and R 2 >.9 Perfect relationship 1 Micropurge sampling concentration (µg/l) 2

20 CORRELATION - SAME ORDER OF MAGNITUDE 2 HydraSleeve sampling concentration (µg/l) 1, Log 1 scale Perfect relationship , Micropurge sampling concentration (µg/l)

21 CORRELATION SAME ORDER OF MAGNITUDE 21 1, HydraSleeve sampling concentration (µg/l) , Micropurge sampling concentration (µg/l) Range of ±1 order of magnitude Perfect relationship

22 CORRELATION SAME ORDER OF MAGNITUDE 22 1, HydraSleeve sampling concentration (µg/l) Pentachlorophenol y =.6134x R² =.3744 One order of magnitude acceptance criteria , Micropurge sampling concentration (µg/l)

23 CORRELATION SAME ORDER OF MAGNITUDE 23 HydraSleeve sampling concentration (µg/l) 1, 1, 1, Benzene y = x R² =.9445 Focus on site adopted criteria , 1, 1, Micropurge sampling concentration (µg/l)

24 TRIAL SUMMARY OF CORRELATION 24 1, HydraSleeve sampling concentration (µg/l) Range of ±1 order of magnitude 99.99% of data points plot within this range , Micropurge sampling concentration (µg/l)

25 STRATIFICATION BTEX concentrations Vertical stratification within well Limited dataset HydraSleeve can identify vertical stratification HydraSleeve can identify source wells Sum BTEX concentration (µg/l) Shallow Deep Micropurge sample results 5 Non-source well Source well Non-source well

26 DATA QUALITY 26 VOCs No-flow results predominantly higher than low-flow results (low-flow potentially under reporting VOCs) Chlorinated phenols (may not apply to other chlorinated compounds) No-flow results predominantly higher than low-flow results, except pentachlorophenol which was lower Metals No-flow results predominantly lower than low-flow results Inorganics Excellent correlation (except ionic balance) 99.99% of no-flow data points in trial are the same order of magnitude as their respective low-flow results

27 ACCEPTANCE AND BENEFITS Technical acceptance Low-flow is accepted by the regulatory community Low-flow is benchmark assume results are correct No-flow results show excellent correlation for wide range of analytes y, R 2 and order of magnitude level of confidence Allows snap shot of multiple depths at one time Appropriate for low and high yield wells Auditor endorsement of HydraSleeve at Site A and working toward endorsement at Site B Commercial benefits 28% cost saving using.6l no-flow samplers over low-flow in the first year and 4% for subsequent years (equivalent to ExxonMobil (27) findings) No saving for 2L samples

28 REFERENCES Britt et al (21). A down hole passive sampling method to avoid bias and error from groundwater sample handling, Environmental Science & Technology 21, 44, ExxonMobil Global Remediation (27). Best practice for selection and use of no-purge groundwater sampling methods Parsons (25). Results report for the demonstration of no-purge groundwater sampling devices at former McClellan Air Force Base, California. Prepared for US Army Corps of Engineers, Omaha District & Air Force Centre for environmental excellence & Air Force Real Property Agency Pearsall and Eckhardt (1987). Effects of sampling equipment and procedures on the concentrations of TCE and related compounds in groundwater samples. Spring 1987 Groundwater Monitoring and Remediation Sundaram et al (29). Groundwater sampling and analysis a field guide. Geoscience Australia 29/27 95pp US Geological Survey (212). Comparison of no-purge and pumped sampling methods for monitoring concentrations of ordnance related compounds in groundwater, Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts Scientific investigations report Zumbro (214). Performance comparison of no-purge samplers for long-term monitoring of a chlorinated solvent plume. Ninth International Conference on Remediation of Chlorinated and Recalcitrant Compounds Monterey, CA, 214