Prior to entering the AFO barrier, the contaminated ground water contains between 14,870 and 17,590 mg/L dissolved uranium. After traveling 0.61 m into the reactive barrier, the uranium concentration is reduced to less than 500 mg/L.
The observed increase in uranium concentration after the ground water exits each of the barriers is from uranium that is desorbed from the previously contaminated colluvial sediments. In an actual ground-water remediation application, the uranium would not increase after exiting the barriers because the reactive chemical barrier would be positioned in uncontaminated sediments downgradient from the maximum extent of the plume.