I am trying to plot simple Piper, Stiff, and Durov plots of groundwater samples collected over a field season. Laboratory results report HCO3- (mg/L), CO32- (mg/L), and alkalinity as CaCO3 (mg/L). For samples with pH > 8.1, CO32- is non-zero, and I would like to represent it accurately in the HCO3- + CO32- axes of the plots. However, on the geochemist spreadsheet, it doesn’t appear that HCO3- and CO32- can be input separately as free variables.
What is the best way to input the necessary data for the dissolved inorganic carbon system in order for the plots to be most accurate? Is it best to put HCO3- as a free variable and include alkalinity as CaCO3 as another analyte, and then GWB will calculate the HCO3- + CO32- in the plot? Or should I convert both CO32- (mg/L) and HCO3-(mg/L) to meq/L as HCO3- and add them together, and use that as my HCO3- as a bulk variable?
Thanks!
