Fig. 3. Observed and modeled breakthrough curves generated from the DML-1, IES-1, IES-2, and DML-2 columns, where DML is the Des Moines Lobe and IES is the Iowan Erosion Surface. The dashed vertical line indicates the time for 1 pore volume (PV) to pass through each column. MIM, mobile–immobile model; PFBA, pentafluorobenzoic acid; PIPES, 1,4-piperazinediethanesulfonic acid disodium salt.