How to get radionuclide concentrations recognized in React

[Gregg W. Jones]

Hi Jia - you helped me with this issue a while back but it's still not clear to me.  I asked about how to specify units for radioactivity and this was your response: 

"GSS contains a default list of common units for describing concentrations in water chemistry analyses. Radioactivity units are not among them. If you want to specify a unit for radioactivity you can set a user-defined analyte. To do so, go to "+ analyte" -> 'user analyte...' -> Edit. Enter a name for your analyte and then set the category to 'Chemical parameters' and the dimension to 'Radioactive emission'. The default unit will then be set to pCi/l."  

You went on to say: "Please note that user analytes are not considered in chemical calculations. For more information, please refer to section 3.3.4 User Analytes of the GWB Essentials Guide.

I responded back - One question about your response - you say that user analytes are not considered in chemical calculations. Regarding radium, it is in the thermo data base I'm using - I'm just defining its unit as pCi/L.  So if I do that, are you saying Radium won't be considered in chemical calculations?  I read section 3.3.4 in the Essentials Guide as you suggested but I don't see anything about the user defined analyte.

I didn't see that I got a response from you on this.  I have a site where I have exceedances of radium and I need to include it in the model.  Surely there's a way for radionuclides entered in pCi/l to be considered in chemical calculations???     

[Jia Wang]

Hello Gregg,

I responded to your question at the top of my last post in your initial thread, but I can clarify.

In GSS, you can define a user analyte for plotting but this type of analyte cannot be used to parameterize a React (or SpecE8, Phase2, X1t/X2t) calculation. The unit of pCi/l is not one of the concentration units accepted by the React application. You can find all units accepted by each GWB application in the GWB Command Reference. For units accepted by React, you would want to look at section 6.1 in the Command Reference. You would need to convert your radium concentration to one of the units accepted by React before adding the component to your simulation.

I referred you to section 3.3.4 User analytes in the GWB Essentials Guide, which details how users can define a user analyte for the spreadsheet. When you have the concentration units converted outside of GSS, you can add radium to the spreadsheet as a "Basis species" and add in the values calculated. Note that the list of "Basis species" are populated from the thermodynamic dataset loaded for the current spreadsheet.

Hope this helps,
Jia Wang
Aqueous Solutions LLC