Hello,
I am trying to develop a Hydrus-HP1 model to simulate the transport and degradation of a single pesticide in 1-D. I have successfully implemented first-order (microbial) degradation and linear instantaneous sorption but I am having difficulty figuring out the appropriate DATA blocks/code for the PHREEQC.in file to define simple volatilization of the pesticide. The fate data I have to characterize the pesticide's volatilization is the Henry's constant but I have the vapor density and aqueous solubility properties used to calculate that constant as well. I have looked throughout the Hydrus and PHREEQC documentation for examples of volatilization but have not found code that works for my problem.
Could you please provide some sample code for the PHREEQC.in file that would define the appropriate thermodynamic data of an organic chemical (e.g., using Henry's constant in the PHASE block) and the appropriate geochemical model (using PHREEQC blocks/commands) to simulate simple volatilization during the transport in the 1-D domain? The code can be very general and I'll study it to figure out how to adapt it to my problem. Thank you!
Nels Ruud