Characterization of the Physical and Chemical Controls on the Environmental Geochemical Behavior of Beryllium

In this dissertation, we investigate the geochemical controls on the behavior of beryllium to better constrain its use as a geomorphologic and geochronologic tool and to characterize its potential mobility as a toxic environmental contaminant. First, we investigated the effects of soil chemistry on beryllium retention. We find that beryllium sorption varies significantly depending on the pH, complexing ligand and type of mineral present. Overall, sulfur and phosphorus oxides as well as soil acidity exert the strongest control on beryllium sorption. Next, we investigated the relative effect of different chemical perturbations on the desorption of beryllium from organic ligands and minerals that demonstrated particular sorption ability in our first body of work. We determined that reducing the pH promoted the greatest amount of beryllium desorption. Overall, we found that beryllium sorbed to organic compounds was more resistant to desorption relative to mineral-bound beryllium. We estimate that beryllium sorption by the organic ligands tested and illite were governed by inner sphere complexation while outer sphere processes were more prevalent among montmorillonite. Finally, with a new understanding of the chemical controls on beryllium retention from our previous work, we are able to develop a mathematical relationship that predicts the beryllium sorption capacity of a system based on the product of the cation exchange capacity and inverse percent quartz. We can use this relationship to compare beryllium concentrations from field measurements to the total beryllium sorption capacity independent of the specific physical and chemical properties of soil