Abstract
ADSORP is a simple BASIC computer program conceived for the determination of the equilibrium speciation of trace elements. Only 1 family (REDEQL 2, MINEQL and GEOCHEM) among the existing programs can already take adsorption processes into account. ADSORP differs from them in the definition of the adsorption process, the introduction of the adsorption of trace element complexes, and the simplicity of the mathematics (method of convergence).