Mobility of pharmaceuticals carbamazepine, diclofenac, ibuprofen, and propyphenazone in miscible-displacement experiments

Many pharmaceuticals pass the unsaturated zone before reaching an aquifer. Therefore, laboratory sand column transport experiments were conducted to study the transport behavior of carbamazepine, diclofenac, ibuprofen, and propyphenazone under unsaturated conditions. The test water was artificial sewage effluent to simulate the infiltration of reused wastewater. The test water was spiked with the pharmaceutically active compounds and the tracer LiCl. Afterwards it was passed through laboratory sand columns, one experiment for each pharmaceutical. The physical and chemical parameters were recorded and general ions measured. Pharmaceuticals were measured using solid phase extraction, derivatization, and detection with GC-MS. The column experiments indicate a significant elimination of ibuprofen (54%), propyphenazone (55%), and diclofenac (35%), whereas carbamazepine was not eliminated. Retardation factors varied between 1.84 for carbamazepine, 2.51 for propyphenazone, 3.00 for ibuprofen, and 4.80 for diclofenac. These results show that mobility and elimination of diclofenac, ibuprofen, and propyphenazone is about in the same range as for experiments under saturated conditions whereas carbamazepine had a significantly lower sorption and elimination under unsaturated conditions.     

Activated soil filters for removal of biocides from contaminated run-off and waste-waters

Building facades can be equipped with biocides to prevent formation of algal, fungal and bacterial films. Thus run-off waters may contain these highly active compounds. In this study, the removal of several groups of biocides from contaminated waters by means of an activated soil filter was studied.A technical scale activated vertical soil filter (biofilter) with different layers (peat, sand and gravel), was planted with reed (Phragmites australis) and used to study the removal rates and fate of hydrophilic to moderate hydrophobic (log K_ow 1.8-4.4) biocides and biocide metabolites such as: Terbutryn, Cybutryn (Irgarol® 1051), Descyclopropyl-Cybutryn (Cybutryn and Terbutryn metabolite), Isoproturon, Diuron, and its metabolite Diuron-desmonomethyl, Benzo-isothiazolinone, n-Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone and Iodocarbamate (Iodocarb). Three experiments were performed: the first one (36 d) under low flow conditions (61 L m⁻² d⁻¹) reached removal rates between 82% and 100%. The second one was performed to study high flow conditions: During this experiment, water was added as a pulse to the filter system with a hydraulic load of 255 L m⁻² within 5 min (retention time <1 h). During this experiment the removal rates of the compounds decreased drastically. For five compounds (Cybutryn, Descyclopropyl-Cybutryn, Diuron, Isoproturon, and Iodocarb) the removal dropped temporarily below 60%, while it was always above 70% for the others (Terbutryn, Benzo-isothiazolinone, n-Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone). However, this removal is a considerable improvement compared to direct discharge into surface waters or infiltration into soil without appropriate removal. In the last experiment the removal efficiencies of the different layers were studied. Though the peat layer was responsible for most of the removal, the sand and gravel layers also contributed significantly for some compounds. All compounds are rather removed by degradation than by sorption.     

Determination of sorption coefficients of pharmaceutically active substances carbamazepine, diclofenac, and ibuprofen, in sandy sediments

Laboratory batch studies were conducted to characterize the sorption behavior of three pharmaceutically active substances (carbamazepine, diclofenac, and ibuprofen) in different sediment types. The sediments were natural sandy sediments from the water saturated zone and the unsaturated zone in the Berlin (Germany) area. They are characterized as medium and fine-grained sands, both with low organic carbon content. The results of the experiments show that sorption coefficients were generally quite low. Distribution coefficients (K(d) values) determined by the batch experiments varied from 0.21 to 5.32 for carbamazepine, 0.55 to 4.66 for diclofenac, and 0.18 to 1.69 for ibuprofen. Comparison of the organic carbon normalized sorption coefficient K(OC) values based on correlation equations with actual experimental data revealed that the calculated data for carbamazepine is of the same order as the experimental data. For diclofenac and ibuprofen the calculated values are much higher than the experimental data, showing a much higher mobility of diclofenac and ibuprofen in natural aquifer sediments than indicated by correlation equations based on octanol water distribution coefficients.