The presence of pharmaceuticals in the environment poses potential hazards to inhabitants and their ecosystems; it is therefore necessary to study the fate and transport of these compounds through soil and groundwater. One major assumption in sorption testing has been that pharmaceuticals readily adsorb to soils with high organic carbon content, but spread through soils and groundwater where there is little organic carbon. The soil used in this study was collected from the Brisson Farm in Eastern North Carolina, where excess medications were introduced to the environment through a septic tank in 2012. Batch experiments were conducted to measure adsorption onto this low organic-carbon soil. Measured adsorption coefficients (Kd) for carbamazepine, acetaminophen, bisphenol-A, and caffeine onto soil from the Brisson Farm were 0.0501 L/kg, 0.102 L/kg, 3.82 L/kg, and 41.2 L/kg, respectively. Findings from this study were then compared to previously measured values using representative soils from Western North Carolina and various soil components. The Brisson Farm, possessing montmorillonite and kaolinite but roughly no organic carbon, has demonstrated via measured Kd values that soil minerals can be the driving force for adsorption when organic carbon is lacking.
