Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Virginia Institute of Marine Science


The sorption of nonpolar organic chemicals on hydrous oxides, clay minerals, and subsurface aquifer materials was studied using the batch isotherm technique. Radiolabeled (&\sp{lcub}14{rcub}&C) trichloroethylene, orthodichlorobenzene, naphthalene, and 1-methylnaphthalene were sorbed on mineral sorbents, subsurface aquifer materials, and a surface soil at six different equilibrium concentrations over a concentration range from 0.001 mg/L to 1.0 mg/L. A knowledge of the sorption coefficients of these fuel components and solvents is necessary to predict the transport of these chemicals through groundwater systems and ultimately to rivers, lakes, and estuaries. Sorption on oxides and surface soils was found to be pH-dependent with decreased sorption at high pH. Increased ionic strength showed a slight increase in sorption on surface soils and some oxides. Sodium montmorillonite and Barasyn, a synthetic montmorillonite, sorbed more of the nonpolar sorbates than the oxides, but less than the surface soil. Aluminum-saturated montmorillonite took up more sorbate than calcium-or sodium-saturated montmorillonites, but the aluminum saturation process apparently involved changes in the clay structure. Aquifer materials sorbed small amounts (&<&3&\mu&g/g) of the nonpolar organics. Sorption coefficients for two nonpolar sorbates were determined on seven different aquifer materials. K&\sb{lcub}\rm oc{rcub}& varied by a factor of 10 over the aquifer material sorbents. Various sorbent chemical and physical properties, in addition to organic carbon, were measured to discover any correlations between the properties and sorption coefficients. No predictive relationship was found between the sorption coefficient and selected chemical/physical properties of the sorbents. Since the K&\sb{lcub}\rm oc{rcub}& concept failed for the aquifer materials studied here and other predictive relations were not found, sorption coefficients must be determined for each aquifer material occurring at a contaminated site. These coefficients must be used in contaminant transport calculations.



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