WEF Discussion Forums
Laboratory Management and Technical Issues
Probe vs. Winkler or modifications for DO standardization
From the Administrator:
What was wrong with the content that you needed to delete it?
I think that the intent of this thread was comparing Winkler DO with different probe calibration techniques. The first thing the analyst needs to know is the precision of the Winkler titration that will be used to assign a value to the DO probe.
Then after calibrating the DO probe with your standard technique, are you within the precision of the Winkler method? If you are, then the calibration technique is good. You can always do a Winkler titration of the standard use to calibrate the probe if you use the DO saturated water method.
I believe one of the posters requested it.
A better question is why with this "new and improved" format, individual posts can't be deleted instead of deleting complete thereads which contained good information.
I know many people were wondering about the content of this thread and why it was removed. It was removed because of an ongoing trial in Hood River Co, Oregon and posts that inappropriately refered to that trial. Well, that trial is now history. Actually, it never happened, or at least never went before a jury because the plaintif settled out of court. This was a victory for the state of Oregon, and it was a victory in which the BOD test played an important role. More in a follow up post.
In some of the deleted posts in this thread, discussions were touching upon some sensitive issues that came up in the pretrial hearings regarding the BOD5 test. That is why I asked that they be removed. The pretrial hearings, or "Daubert" hearings were intended to lay the scientific and technical groundwork for the full blown trial. It was at these hearings that the BOD5 test underwent extensive scrutiny by the defense. Basically the issue was that an owner of a fruit processing plant in Hood River was facing possible jail time for polluting streams near his plant, and the prosecutor's evidence was heavily reliant upon BOD5 data to push the case through. THis was an important case in Oregon, and one in which the Attorney General himself was involved with as his own career was potentially at stake. So, all this means we as BOD5 chemists had to really be at the top of our game. All told, 10-12 hours were spent on the stand at the Daubert hearing defending the BOD5 method and the data.
more if there is interest..I can talk about specific issues that came up. It would seem there might be some interest here in how the method and data was attacked, and also how we defended it. The main issues that came up were nitrification (without CBOD we did not have control over the NH3N component), method uncertainty, supersaturated samples and the overall "crudeness" or lack of specificity of the method.
I will get back at some point but it might not be right away. Since I was not the only one testifying, a full response would mean talking to my coworkers about their testimony as well. Thanks for the interest -
This might be a good session for PNCWA or a short school technical session.