Sorption influenced transport of ionizable pharmaceuticals onto a natural sandy aquifer sediment at different pH.
The pH-dependent transport of eight selected ionizable pharmaceuticals was investigated by using saturated column experiments. Seventy-eight different breakthrough curves on a natural sandy aquifer material were produced and compared for three different pH levels at otherwise constant conditions. The experimentally obtained K(OC) data were compared with calculated K(OC) values derived from two different logK(OW)-logK(OC) correlation approaches. A significant pH-dependence on sorption was observed for all compounds with pK(a) in the considered pH range. Strong retardation was measured for several compounds despite their hydrophilic character. Besides an overall underestimation of K(OC), the comparison between calculated and measured values only yields meaningful results for the acidic and neutral compounds. Basic compounds retarded much stronger than expected, particularly at low pH when their cationic species dominated. This is caused by additional ionic interactions, such as cation exchange processes, which are insufficiently considered in the applied K(OC) correlations.
Geoscience Centre, Dept. Applied Geology, University of Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany. Mario.Schaffer@geo.uni-goettingen.de
Mario
M
Schaffer
Norman
N
Boxberger
Hilmar
H
Börnick
Tobias
T
Licha
Eckhard
E
Worch
D000327:Adsorption; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D004364:Pharmaceutical Preparations; D014874:Water Pollutants, Chemical