Original PaperTemperature and pH-stability of commercial stationary phasesIn this paper, the temperature and pH stability of silica-based RP stationary phases were investigated. Furthermore, nonsiliceous phases like a polymeric column based on polystyrene divinylbenzene and a polybutadiene coated zirconium dioxide column were also included. The columns were heated up to 1508C at dynamic conditions, which means that the eluent consisting of water and methanol (90:10, v/v) was continuously purged through the packed bed. After every 5 h, the columns were cooled down to room temperature and the efficiency was measured by injecting a test sample based on the Neue test. It could be shown that some stationary phases exhibited a very good temperature stability at the test conditions specified above.

The aim of the study was to present first preliminary characterization of Turkish hospital wastewaters, their environmental risk, and a method for toxicity assessment. The hospital wastewater samples were collected from two of the largest medical faculty hospitals and a training and research hospital in Istanbul, Turkey. The samples from the selected hospitals were taken as grab samples on March 2014. Overall, 55 substances including pharmaceuticals and their metabolites, pesticides, and corrosion inhibitors were analyzed in all hospital wastewaters. Analysis of toxicity and the antibiotic resistance bacteria were investigated in addition to the chemical analysis in the wastewater of one hospital. Hazard quotients (HQs) and toxic units (TUs) were calculated as basis of the environmental risk assessment. Fourteen pharmaceuticals in hospital wastewater (HWW) were classified as "high risk" with HQ > 10. HQ values higher than 100 were determined for five antibiotics and one analgesic, namely, ofloxacin, clarithromycin, ciprofloxacin, sulfapyridine, trimethoprim, and diclofenac. Ofloxacin with an HQ of 9090 was observed to be the most hazardous compound. HQ and TU values of the wastewater treatment plant (WWTP) effluent dropped significantly due to dilution in the sewer. Further elimination by biological degradation or adsorption was observed only in some cases. However, the decreased HQ values do not the change environmental load significantly. Therefore, advanced treatment processes should be applied to remove the persistent compounds. In combination with the results on antibiotic resistance, we would prefer on-site treatment of hospital wastewater. Toxicological assessment was performed using cytotoxic and mutagenic screening tests. The results of the Ames assay showed that the native hospital wastewaters had strongly mutagenic activity with a ≤10-fold increase relative to negative controls. The mutagenic potentials of the samples were generally concentration and metabolic activation dependent. Multiple antibiotic resistances were demonstrated with the tested isolates to ciprofloxacin, trimethoprim, and ceftazidime. This study demonstrates that the hospital wastewaters in Istanbul exhibit strong environmental and toxicological risks, as well as high multiple drug resistance to commonly used antibiotics.

Effluents from municipal wastewater treatment plants (WWTPs) are known to be point sources of micropollutants for surface waters. The aim of this study was to examine a reconstructed full-scale ozonation equipped with a pump-injector system for ozone (O) dosage and a fluidized moving-bed reactor as biological posttreatment at a municipal WWTP utilizing an effect-directed approach. This approach consists of chemical analysis in combination with toxicological tests for the assessment of treatment efficiency of the plant. Chemical analysis showed elimination rates > 80% for pharmaceuticals and industrial chemicals. Analysis of endocrine disruptors was limited due to substance concentrations below the limit of detection (LOD). Estrogenic activity was detected by the Arxula Adeninivorans yeast estrogen screen (A-YES) at low concentrations (pg to ng EEQ/l range). Estrogenic activity was reduced by more than 90% after ozonation. In contrast, androgenic activity (measured in the Adeninivorans yeast androgen screen, A-YAS) was still found after O treatment and after biological posttreatment, which is consistent with the data obtained by chemical analysis. Furthermore, no marked genotoxic or cytotoxic effects were observed after ozonation using the alkaline comet and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid (MTT) assays, respectively. Results suggest that the applied specific O dose of 0.4 mg/mg is a safe operation setup in terms of toxicologically relevant transformation products. In addition, no adverse effects on primary producers, as evidenced by algae growth inhibition tests, were detected. The monitored biofilm growth in the biological posttreatment exhibited a steady state after one month. Based on computational fluid dynamics (CFD) simulations and biomass, one might conclude that O did not apparently enter biological posttreatment to a great extent and that hydraulic retention time in the O reactor was sufficient. Our data demonstrate the effectiveness of a full-scale O treatment in combination with a fluidized moving-bed reactor as biological posttreatment for the reduction of a majority of micropollutants without the release of relevant toxic transformation products as assessed by a chemical and toxicity-based approach.

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