Some ins and outs about the Membrane Interface Probe

1. The Membrane Interface Probe Some ins and outs

2. 2 Program The Membrane Interface Probe Standard Practise (ASTM D7352-07) Direct push machines (Geoprobe and CPT) MIP ≠MIP Influences and detection limits

4. PID (Photo Ionization Detector)Ionization Potential < 10,6 eV

6. Simultaneous logging of geological, hydrogeological and chemical subsurface properties.

7. Digital data recording

8. Measurement range from 300 ppb – NAPL

10. Information in a fieldreport Site information Data and time MIP-log is obtained MIP contractor, field technician and assistants File name of MIP-logging location and depth of final penetration. File name of the pre-log response test along with compound used and concentration. File name of the post-log response test along with compound used and concentration. Equipment used in the investigation. Site and locations specific info.

11. Direct push machines

12. Mobile In Situ Techniques

13. Direct push machines GEOPROBE 6610DT 20t-Minicrawler Stand-Alone-CPT-Rig (15 t)

14. MIP ≠MIP MIP technology is >15 years old. Several MIP-service providers have made adjustments to their system. Geoprobe has developed system as well. MIP technique is still being improved (Enissa MIP) All systems are still on the market so MIP ≠MIP!!

15. 11 Membrane Interface Probe : influences Temperature membrane block (70 tot 130 °C) Membrane :Quality is never the same, not with new membranes but certainly not when used. Trunkline(used material, length, temperature of cable can heat the transport line) Detectors (FID, PID, DELCD great difference in quality and stability PID : needs to be cleaned regularly for a stable baseline DELCD : central electrode may shift resulting in a false positive signal only on DELCD Gasses : H2S can give a respons on the DELCD! CH4 can cause quenching on PID and DELCD geven. Lithology and type of contamination. High concentration : carry over on detectors, contamination of membrane and trunk line. Heated trunk-line and being able to better heat the membrane block can minimize the effect.

16. They all affect the detection limits Some examples MIP detection limits by VITO (2008) Detection limits mentioned by Geoprobe and service providers.

17. 13 Detectionlimitsaccording to Belgium’s VITO 02.2008(OLD MIP-system)

18. Detection limit can be much lower

19. “Detection” limitsMIP in the field PER : 300 µg/l Tri : 300 µg/l CIS : 300 µg/l VC : 400 µg/l BTEX 300-500 µg/l Enissa MIP (1-10 µg/l) willbepresented later on Note: External factors have a stronginfluenceon the detection limit. These are just a indication and canbehigherorlowerdependingontehexternal factors. MIP is a screening tool, alwaystake samples forverification. 15

20. MIP developments Developments of the last 15 years Recent development (Enissa MIP)

22. Membrane temperatures between 120 and 130 C in the saturated zone (increased thermodesorption leads to higher sensitivity)

23. Simultaneous CPT-EC logging can give indication on preferential pathways or NAPL presence

25. Notes for interpretation Are the data coming from a comparable MIP-system Watch the membrane temperature Be ware of carry over Be ware of quenching of detectors Compare pre- and post-log response test, they should be comparable Remember which detectors should respond to your contaminant, do they all respond???

26. Discussion / remarks