Thermodynamic modeling of heavy metal forms in bottom sediments: By the example of the Ivankovsky Reservoir

The technique of thermodynamic modeling for interactions in system “pore water-solid phase of bottom sediments” is suggested (including dissolved and sorbed forms of heavy metals). The main sorbent phases (clay minerals, iron and manganese hydroxides, and organic matter) are presented as multi-component ideal solid solutions. The capacities of sorbing phases are calculated according to the results of selective extraction by the Tessier scheme supplemented with determination macro-cations. The selectivity constants and free energy of metal bonding (Fe, Mn, Zn, Cu, Ni, Pb, Co, and Cd) with sorbing phases are calculated for bottom sediments of various compositions within the Ivankovsky Reservoir and the estimation of their natural variations is given.