A pilot-scale hospital wastewater treatment plant consisting of a primary clarifier, membrane bioreactor, and five post-treatment technologies including ozone (O3), O3/H2O2, powdered activated carbon (PAC), and low pressure UV light with and without TiO2 was operated to test the elimination efficiencies for 56 micropollutants. The extent of the elimination of the selected micropollutants (pharmaceuticals, metabolites and industrial chemicals) was successfully correlated to physical-chemical properties or molecular structure. By mass loading, 95% of all measured micropollutants in the biologically treated hospital wastewater feeding the post-treatments consisted of iodinated contrast media (ICM). The elimination of ICM by the tested post-treatment technologies was 50-65% when using 1.08 g O3/gDOC, 23 mg/L PAC, or a UV dose of 2400 J/m(2) (254 nm). For the total load of analyzed pharmaceuticals and metabolites excluding ICM the elimination by ozonation, PAC, and UV at the same conditions was 90%, 86%, and 33%, respectively. Thus, the majority of analyzed substances can be efficiently eliminated by ozonation (which also provides disinfection) or PAC (which provides micropollutants removal, not only transformation). Some micropollutants recalcitrant to those two post-treatments, such as the ICM diatrizoate, can be substantially removed only by high doses of UV (96% at 7200 J/m(2)). The tested combined treatments (O3/H2O2 and UV/TiO2) did not improve the elimination compared to the single treatments (O3 and UV).

Little is known about the significance of hospitals as point sources for emission of organic micropollutants into the aquatic environment. A mass flow analysis of pharmaceuticals and diagnostics used in hospitals was performed on the site of a representative Swiss cantonal hospital. Specifically, we analyzed the consumption of iodinated X-ray contrast media (ICM) and cytostatics in their corresponding medical applications of radiology and oncology, respectively, and their discharge into hospital wastewater and eventually into the wastewater of the municipal wastewater treatment plant. Emission levels within one day and over several days were found to correlate with the pharmacokinetic excretion pattern and the consumed amounts in the hospital during these days. ICM total emissions vary substantially from day to day from 255 to 1259 g/d, with a maximum on the day when the highest radiology treatment occurred. Parent cytostatic compounds reach maximal emissions of 8-10 mg/d. A total of 1.1%, 1.4%, and 3.7% of the excreted amounts of the cytostatics 5-fluorouracil, gemcitabine, and 2',2'-difluorodeoxyuridine (main metabolite of gemcitabine), respectively, were found in the hospital wastewater, whereas 49% of the total ICM was detected, showing a high variability among the compounds. These recoveries can essentially be explained by the high amount administered to out-patients (70% for cytostatics and 50% for ICM); therefore, only part of this dose is expected to be excreted on-site. In addition, this study emphasizes critical issues to consider when sampling in hospital sewer systems. Flow proportional sampling over a longer period is crucial to compute robust hospital mass flows.

Lake sediments conserve important information about past conditions of a lake and its environments. We present analyses of calcium, manganese, iron, copper, zinc, cadmium, mercury, and lead in dated (210Pb, 137Cs, varve-chronology) sediment cores from Zürichsee (Lake Zurich), Switzerland, covering a time span of the last 200 years and an additional time interval between 13 500 and 15 000 years before the present time. The concentrations of these elements varied very little in pre-anthropogenic sediments and represent geochemical background concentrations. With the beginning of industrialization in the early 19th century and the corresponding growth of population, significant changes occurred in the concentrations of the investigated metals. Copper, zinc, and cadmium increased until about 1960 and decreased sharply afterwards. The increase correlates to the growth of local industrial productivity (and population growth), whereas the decrease after about 1960 was caused by (i) the introduction of sewage treatment plants, (ii) more stringent legal restrictions for releases of pollution to the environment, and (iii) a growing public awareness toward environmental conservation. Contrary to world-wide observations, the increase of lead by automobile exhausts was not evident in the sediments of Zürichsee. Here, its concentrations remained almost constant between 1900 and 1975. Then they began to decrease due to the reduced use of leaded fuel. Thus, the lead input to the lake by automobile exhausts was nearly compensated by (i) continuously decreasing industrial releases to the environment and (ii) the mentioned improvements of environmental conservation techniques. Despite the consider able improvements in recent times, the present-day concentrations of the investigated heavy elements in sediments of Zürichsee are still much higher than their natural background values.