PARENT SESSION
PS19 - Bioavailability
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P171) PhyavQL: a computer model for estimating metal bioavailability and translocation within plants.

Cypas, Paula^*,1, Hale, Beverley¹, Evans, Les¹, ¹ University of Guelph, Guelph, ON, CANADA

ABSTRACT- A chemical aqueous speciation program designed to model metal bioavailability and translocation within plants is currently under development. The Visual Basic^*TM application uses MICROQL-based algorithms such as mass-action, mass-balance, Jacobian and Newton-Raphson iterations to calculate metal speciation in aqueous media and on root surfaces. Conditional stability constants for root binding sites (K_root-Cu) and translocation coefficients (k) developed from hydroponic experiments are incorporated into the database of chemical thermodynamics as competitive ligands in a Biotic Ligand Model (BLM). The extent of root-bound metal, or maximum bioavailable fraction, is calculated by sequential comparisons of root metal-binding capacity with that of inorganic nutrients and other compounds in solution. Translocation coefficients relate the maximum bioavailable fraction to predict shoot accumulation. The Visual Basic Windows interface provides a user-friendly template for variable input and graphical illustration of changing speciation respective of pH.

Key words: BLM, bioavailability, computer model, plants