GEOCHEM‐PC—A Chemical Speciation Program for IBM and Compatible Personal Computers

The GEOCHEM-PC has evolved into a functional and increasingly convenient research tool that the authors have distributed to interested users in the USA and abroad. The use of GEOCHEM-PC, as well as the alterations the authors have made, largely reflect their research interests in plant mineral nutrition, phytotoxic trace elements, soil solution chemistry, and related topics. This chapter provides an overview of GEOCHEM-PC in its current form, highlights some of the differences between GEOCHEM-PC and its predecessors, clarifies some points regarding program conventions and assumptions, and indicates the plans for future program improvements. GEOCHEM-PC performs redox computations adequately, although some of the conventions for describing the reactions are awkward and nonintuitive. More complex mineral phases (“mixed solids” in the parlance of GEOCHEM) can also be considered, but other programs such as MINTEQA2 are better equipped to model complex solid phases and solid solutions.