#publiclab Meeting

Meeting summary

1. water monitoring (btbonval, 15:08:39)
   1. notes start after meeting started properly (btbonval, 15:10:35)
   2. Jack (on net meeting) is working on syringe pump to sample water (btbonval, 15:15:29)
   3. Jack uses Solaris Launchpad is a microcontroller for $8 (btbonval, 15:35:13)
   4. Wylie asks about shipping reference standards, concerns about lead. Jack adds arsenic and cyanide as additional examples of hazardous materials. Shippers won't be happy, it will be more expensive, but it should be doable. (btbonval, 15:35:16)
   5. Jack says that standards are hazardous materials and they simply have to be handled and disposed off using the appropriate protocol of the local institution being worked with or the originating university of the researcher. (btbonval, 15:35:19)
   6. clarification: Wylie was originally asking about diverse protocols for handling the hazardous standards, and the answer from Jack was that protocols change: no standard protocol for standards. Consult with the local science authorities (btbonval, 15:35:23)
   7. A question was asked something along the lines of if there any suggested sample sizes for different bodies of water. Jack responds that the sampling location is extremely important, need to be over the sewage disposal or chemical disposal on a boat. (btbonval, 15:35:27)
   8. Willy (original asker) asks for clarification about how many samples (from say the Mississippi River) are adequate to say something valid about the waterway (btbonval, 15:35:32)
   9. Leif responds that several samples from tributaries of the main waterway will be telling of the main water source. If the target is found in tributaries, then work up the fork network until the point source of pollution is located. (btbonval, 15:35:35)
   10. Jack adds that the pollutant target being sought will have increasing concentration past each fork as one gets closer to the source. Sediments will concentrate target materials near the point source. (btbonval, 15:35:43)
   11. Dan asks how to handle sediments (btbonval, 15:35:46)
   12. (Clarify Person A) looking for Iron Redox in sediments of LA rivers. The data was noisy and the source of noise could not be determined. The soil sampling in the field ended up being unusable regardless of the protocols recommended by labs. (btbonval, 15:36:01)
   13. Wylie suggested looking into methylation or uptake by plants nearby for stronger sampling certain compounds (btbonval, 15:36:09)
   14. Jack says one way to get Iron into solution from sediment is to digest with Nitric acid. That work will involve non-electrochemical detection: atomic emission/absorption. Mostly wet lab techniques due to handling of nitric acids (btbonval, 15:36:13)
   15. Jack ends remote connection (btbonval, 15:36:17)
   16. IDEA: Matt is going to start a potentiostat mailing list. (btbonval, 15:36:22)
   17. Catherine asks will Jack's simple kit be distributed through Public Lab? Leif thinks maybe. (btbonval, 15:36:26)
   18. Leif chases sewage overflow and is like tots pro at it. (btbonval, 15:36:53)
   19. Leif recommends real time data feeds (e.g. GPRS) of water sampling sensors because data logging is prone to loss due to sensor being compromised (water breaches into electric components or washes away) (btbonval, 15:38:16)
   20. Leif publishes data to Xively (internet of things platform formerly called Cosm formerly called Pachube) (btbonval, 15:39:15)
   21. Leif prefers serial output sensors because it maximizes the devices that can interface it easily (Arduino, Raspberry Pi, serial/USB on computers, so on) (btbonval, 15:40:07)
   22. Leif uses Vernier linear sensors for being cheap and easy to use. nonlinear sensors have neat configuration parameters, which is apparently super duper exciting. (btbonval, 15:41:18)
   23. Matt says many sensors don't usually offer ways to hook up to anything but the proprietary software/hardware interfaces, and when asked, will push back. (btbonval, 15:42:03)
   24. Leif and Matt like Vernier because the sensors don't require the proprietary interfaces (btbonval, 15:42:36)
   25. conductivity probes need to purchased considering where they will be placed (eg salt water vs fresh water) because the probes usually have limited ranges. (btbonval, 15:44:13)
   26. Matt asks what sort of DIY stuff is all this cheap and easy to use stuff good for? (btbonval, 15:44:46)
   27. Don interjects that teachers are already building curricula around Vernier sensors (btbonval, 15:45:09)
   28. (Leif reminds a problem raised by Jack) the conductivity sensors cause electrolysis of water which leads to metal deposition plating on the probes, which limits their lifetime. gold tipped probes don't plate out as fast (btbonval, 15:46:49)
   29. Leif is using a platinum tipped probe which can last something like six months of use due to the inactivity of platinum (btbonval, 15:47:32)
   30. Leif: water conductivity changes based on salinity, total dissolved solids, all kinds of salts, pollution which all conflate the conductivity calculation. It's one of 4-5 measures for water quality. (btbonval, 15:49:07)
   31. Catherine asks about the other measures. Bacteria, Dissolved Oxygen, pH, redox potential. (btbonval, 15:49:29)
   32. clarification: answer from Leif (btbonval, 15:49:38)
   33. pH and redox help understand about metals and solids in the water, conductivity is already noted, dissolved oxygen and bacteria help understand biological influences in the water. Taken together they can tease out conflation between measurements better than any measure taken alone (btbonval, 15:50:36)
   34. Matt talks about cheapstat which requires advanced soldering and electronics, but its extremely inexpensive and there is a peer reviewed paper with arsenic detection in solids using it (btbonval, 15:51:36)
   35. Matt, at a space in Portland, will be discussing techniques for hacking SMD (surface mount, tiny tiny) electronics since it isn't the easiest of electronics to work with by hand (btbonval, 15:53:55)
   36. Leif says that redox on probes is a probable source of failure (btbonval, 15:55:13)
   37. IDEA: Leif will present the specifics of his particular probe and make plans for dropping it in water as a Barnraising activity (btbonval, 15:56:26)

Action items

1. (none)

People present (lines said)

1. btbonval (41)
2. meeting (2)