Hello Dr. Parkhurst, I'm not certain if you are still answering the questions about PHREEQC, and don't expect that this question will have significance to anyone other than myself, but I have read all the questions on the PhreeqcI webpage and have yet another. I have been using the 2.4.2 Alpha version of Phreeqc Interactive and selecting the wateq4f database because I am interested in allophane, and the phreeqc database does not include allophane. Here's the strange thing: if I put the same data into PHREEQC (with the wateq4f database selected) as were put into WATEQ, I will get allophane as supersaturated in the WATEQ results, but allophane is not even listed in the PHREEQC phase results. Some of the other mineral phase log IAP values are dead on, most are off a little and others are off more, with no clear pattern in the results (so I think I am entering them all correctly). I would expect that with the same input and same databases, the log IAP values would be a little off, but that the same mineral phases would appear in the output. Is this an incorrect assumption? I understand that the easiest thing for me to do is to use WATEQ, but I have never used it (I got the run output from someone else) and prefer the comfort of PHREEQC. Any help would be greatly appreciated, Caroline
Please note that some U.S. Geological Survey (USGS) information accessed through this page may be preliminary in nature and presented prior to final review and approval by the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.
Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.
The URL of this page is:
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 1963 since Jan 22, 1998.