Re: Estimating Eh from DO

["David L Parkhurst" <dlpark@xxxxxxxx>]

One way is to run PHREEQC inputting dissolved oxygen as O(0) in PHREEQC
notation. A pe and Eh will be calculated and printed under a heading "Redox
Couples" in the output.

But I have to add that the DO is a more useful quantity than the Eh, which
is hard to measure and difficult to interpret. If you have DO, you are
automatically close to the upper stability field for water on a Eh-pH
diagram.

David

SOLUTION 1
      -temp 15
      -units      mg/L
      pH    7.3
      O(0)  3.4
END

David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225

Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled



                                                                                                          
                      "Doug Craft"                                                                        
                      <DCRAFT@xxxxxxxxx        To:       <dlpark@xxxxxxxx>                                
                      ov>                      cc:                                                        
                                               Subject:  Estimating Eh from DO                            
                      07/14/03 02:54 PM                                                                   
                                                                                                          
                                                                                                          




Hi Dave-

Sorry to bother you, I know you are busy...

I have been searching for a straightforward calculation to estimate Eh from
DO in oxgenated surface waters - I stumbled across your Phreeqe IAQ but did
not find the specific question answered.  I have field measured T, pH, but
had the redox electrode go whack on me.

Do you have a simple formula or can you provide me a reference where it can
be obtained?

Appreciate your help!

Doug


Doug Craft
Fisheries Applications Research Group
USDI - Bureau of Reclamation
PO Box 25007, D-8290
Denver CO 80225-0007
dcraft@xxxxxxxxxxx
office: 303-445-2182  office cell: 303-870-5625
office fax: 303-445-6328
home: bigdoug@xxxxxxxxx  303-458-8946