Laserfiche WebLink
• • A5 <br /> ferrous iron. This results in the consumption of hydrogen ions <br /> and an elevation of pH from an acid plume , but with the <br /> undesirable side reaction of dissolution of previously <br /> precipitated iron. <br /> j CONCEPTUAL GEOCHEMICAL MODEL <br /> } The above preceding discussions of geochemical reactions provide <br /> sufficient background to enable the development of a conceptual <br /> geoc4emical model for contaminant mobilization , transport and <br /> removal . This model is similar to that presented by Cherry , <br /> Shepherd, and Morin (February 14- 18 , 1982 ) and is based on the <br /> results of the many investigators in this field, as well as the <br /> authors ' own field experience at uranium, phosphate, and copper <br /> sites throughout the U. S. , Canada, and Australia. <br /> 1 When a highly acidic water percolates from a process water <br /> source , the initiation of calcite dissolution occurs at the <br /> advancing wetted front. As the plume proceeds downgradient , a <br /> total of three zones form. <br /> The first zone , which may be termed the "acid" or "core" zone, <br /> consists of ground water with a quality virtually identical to <br /> that of the source. The water is characterized by extremely low <br /> ipH , the presence of very high sulfate ion concentrations, often <br /> i <br /> i <br />