TRANSPORT AND MOBILITY OF PHARMACEUTICALS IN THE SATURATED ZONE

Occurrences of pharmaceutically active compounds (PhACs) in surface and sewage water have widely been reported. Investigations show the presence of several classes of pharmaceuticals such as anti-inflammatory drugs (e.g. diclofenac), analgesics (e.g. propyphenazone), and blood lipid regulators (clofibric acid) even in ground water. In field studies investigating ground water sampled at a bank infiltration site at Lake Tegel, Berlin (Germany), clofibric acid was found at concentrations up to 290 ng/L, propyphenazone up to 250 ng/L, whereas concentrations of diclofenac were around the detection limit. At other sites from the Berlin area not only clofibric acid, propyphenazone, and diclofenac were analyzed but also ibuprofen (antirheumatic, anti-inflammatory drug) and carbamazepine (antiepileptic drug) could be found in ground water. These occurrences led to the question about the fate of these pharmaceuticals in ground water. The general goal of our investigations was to understand the transport processes for PhACs in ground water.

We conducted laboratory column experiments and field studies to investigate the transport behavior of the pharmaceuticals clofibric acid, propyphenazone, diclofenac, ibuprofen, and carbamazepine. We used sandy sediments from the Berlin area and corresponding ground water to observe the transport of those pharmaceuticals under water saturated conditions in the laboratory. Results show that clofibric acid exhibits no degradation and almost no retardation (Rf=1.1). Diclofenac (Rf=2.6) as well as propyphenazone (Rf=2.0) are retarded whereas significant degradation was not observed for both pharmaceuticals under the prevailing conditions in the soil column. Ibuprofen is degraded under aerobic conditions whereas only little degradation was observed under anaerobic conditions. The retardation factor for ibuprofen was extrapolated to be 4.0. Carbamazepine shows no degradation in the soil column experiments but significant retardation (Rf=2.8) under the prevailing conditions. We conclude that at least clofibric acid, propyphenazone, and carbamazepine are recalcitrant under ground water conditions and will be transported within the aquifer.