Hi there, I'm using PHREEQC to model the speciation of salts in historical water quality data. Can someone please provide a link to a guide/literature on interpreting the results? As well as info on what steps to follow to ensure the validity of the results (e.g. charge balance)?
I teach a course about problems like yours, for which I got a lot of inspiration from this book:
http://www.hydrochemistry.eu/a&p/index.html
It contains a lot of examples and exercises with PHREEQC.
enjoy,
Pieter
I agree with Pieter Bertier that the book of Appelo & Postma is an excellent book for people working in hydrochemistry.
About your question I give an example of selected output of one simulation and some comments:
----------------------------Description of solution-------------
pH = 7.200
pe = 8.400
Specific Conductance (uS/cm, 17 oC) = 523
Density (g/cm3) = 0.99903
Activity of water = 1.000
Ionic strength = 8.293e-003
Mass of water (kg) = 1.000e+000
Total carbon (mol/kg) = 2.430e-003
Total CO2 (mol/kg) = 2.430e-003
Temperature (deg C) = 17.300
Electrical balance (eq) = 8.449e-005
Percent error, 100*(Cat-|An|)/(Cat+|An|) = 0.73
(Comment: This value shows that the % balance error is small (less than 1%). As a rule of thumb analysis with an error
Many thanks for the comments. I got hold of the book and will study it. Thanks for the example Carlos! But I assume the reactions will be different for aqueous solutions?
I'm just wondering is this type of analysis would be applicable porewater, as well as larger water bodies (dams, lakes and rivers)?
In my opinion it could, but the composition reflects the water origin. If the water comes mainly from the discharge of springs its composition depends on water/rock interaction processes. However, there should be some degree of dilution provoked by the input from precipitation.
Respecting redox reactions, in general the superficial water is close to the equilibrium with the partial pressure of atmospheric O2 (log pO2 = -.7) and we can estimate saturation indices of minerals with redox dependent reactions. This could be not true if the water has some degree of pollution.
- Badges
- Science topic
- Similar topics
- Computer Science
- Program