Transactions on Ecology and the Environment vol 65, © 2003 WIT Press, www.witpress.com, ISSN 1743-3541 The comportment of selected pharmaceuticals in sewage treatment plants B. ~trenn',M. ~lara',0. ~ans~ & N. ~reuzin~er' l Institute for Water Quality and Waste Management, Vienna University of Technology, Vienna, Austria. 2 Federal Environment Agency Ltd., Vienna, Austria. Abstract The effluent of sewage treatment plants have been shown to be a significant source of pharmaceutical residuals in surface water. In order to determine and optimise the efficiency of wastewater treatment plants and derive basic knowledge on the behaviour of pharmaceuticals, different treatment steps of a municipal sewage treatment plant were investigated. Ths article deals with common pharmaceutical active compounds (PhAC) for hfferent applications which are known to occur in the effluent of wastewater treatment plants. In particular, two antibiotics (Roxithromycin, Sulfamethoxazole), two analgesicslantiphlogistics (Diclofenac, Ibuprofen), the antiepileptic Carbarnazepine, the contrast meha Iopromide, the tranquilizer Diazepam and the lipid regulator Bezafibrate were selected. The investigations have been performed on a low loaded full-scale activated sludge plant for nutrient-removal and phosphorus precipitation with a high sludge retention time (SRT) of more than 100 days. Since April 2001 grab samples of the influent and effluent were taken once every two months. Furthermore three sampling periods over 10 days were performed in October 2001 and in May and July 2002. Daily composite samples of influent and effluent were taken during these sampling periods. A typical distribution over the year was observed for the antibiotic Roxithromycin in the influent of the treatment plant. Certain substances which showed no or only part elimination in parallel performed lab scale experiments which were implemented with much lower SRT, seemed to be degraded in the full scale plant. These results confm the assumption that the elimination of pharmaceuticals from waste-water correlates with the sludge retention time. Transactions on Ecology and the Environment vol 65, © 2003 WIT Press, www.witpress.com, ISSN 1743-3541 274 Water Pollution \//I: Modclling, Mca~uringand Prediction 1 Introduction In Austria 11,567 medicines for human applications were licensed in January 2002. For these medicines approximately 1,800 different active compounds are in use. In addition to human pharmaceuticals 1,055 veterinary products are accredited [l]. The annual described quantity for the most important pharmaceuticals amounts to more than 100 t per year. Medical substances are developed to effect specific targets in the organism for a limited period of time. By way of excretion, exposure to the environment is suspected. Because of the continuous and wide spread exposure, even low concentration levels may cause effects on aquatic systems. For this reason, unexpected but significant impacts of pharmaceuticals have to be anticipated. Large quantities of medical substances which are used in human and veterinary medicine are suspected to enter rivers, streams and surface water through the eMuent of sewage treatment plants. Surface water can be polluted with these medical compounds by run-off fiom fields treated with dung or application of liquid mure. Pharmaceutical compounds are excreted fiom humans, malnly via urine and faeces, in unchanged form or as metabolites or conjugates. Other medical substances such as ointments and paints get into wastewater directly due to them being washed off Another, not negligible, pathway that contributes to pharmaceutical emissions into the environment is the qroper disposal of domestic sewage. Finally, the pharmaceutical manufacturers represent a sigmficant group concerning another source of environmental intake [2].Concentrations of medical substances up to several pg/l have been found in river water. The discharge of antibiotics into the environment is anticipated to cause the growth of resistant bacterial strains at sub-lethal concentrations [3]. For &IS reason it is necessary to reduce the risks of long-term exposure of pharmaceuticals to the environment and the risk to human health. To achieve this it is necessary to investigate the behaviour of frequently used pharmaceuticals in the different steps of wastewater treatment and to determine the efficiency of sewage treatment plants. The reduction of uncontrolled releases to the environment through wastewater and possible strategies to increase the removal grade concerning the effluent are an especially important target which has to be developed. In the following paper the investigations of the determined Influent and effluent concentrations of a low loaded municipal wastewater treatment plant are described. The presented results are part of the investigations which were performed according to the EU project POSEIDON (EVK1-2000-00546). 2 Selected substances In the following Table 1 the investigated pharmaceuticals and their consumed quantities in Austria in 1997 are displayed [4]. The most prescribed pharmaceuticals in human medicine are medicaments with paregoric and anti-inflammatory effects, so called analgesics or antiphlogistics. For example the analgesic Diclofenac whch is especially used to relieve symptoms of Transactions on Ecology and the Environment vol 65, © 2003 WIT Press, www.witpress.com, ISSN 1743-3541 Wawr- Pollurion VII: Moddhrrg, Mea~ur-rngattd Pwdicriorl 275 arthritis and such as lnflarnmation or joint pain is excreted with about 60 % as glucuronides through urine [5]. Ibuprofen is an anti-inflammatory drug whlch is often applied instead of acetylsalicylic acid (Aspirin@) and it is very common in use because it is prescription fiee. The tranquilizer Diazepam is used to treat anxiety as well as epilepsy and muscle spasms and causes sedation. The common trade mark for it is Valium@. The medxal substance Bezafibrate is applied as lipid regulating agent. It &bits the composition of cholesterol and triglyceride in the liver whereby the portion of these lipids is decreased in the blood. Bezafibrate is excreted mainly via urine, 50 % of the a-stered dose in unchanged form and 20 % in form of glucuronides PI. Carbamazepine is used for the treatment of epilepsy. The drug is degraded in the liver to active metabolites which are as active as the parent drug. Only 2 to 3 % of the administered dose is excreted in unchanged fom From the antibiotics the substances Sulfamethoxazole and Roxithromycin were selected as frequently used agents. The sulfonamide Sulfamethoxazole inhibits bacterial growth. Also Roxithromycin, a rnacrolide antibiotic, affects antibacterial wherefore it is used to treat many different lunds of infections. The drug gets mamly concentrated in the bile. The contrast medium Iopromide contains iodine and is a very frequently used pharmaceutical for X-ray recording. Contrast media are used for X-ray representations of special body parts. The substance is usually better or worse absorbed by the X-ray than from the ambient body tissues. After application 90 to 100 % of the drug will be excreted in unmetabolised form. Table 1: Examined drug compounds and quantities consumed in Austria in 1997 Diclofenac AnalgesicsIAntiphlogistics lbuprofen Tranquilizer Diazepam Lipid regulator Bezafibrate 4474 Antiepileptic Carbamazepine 6334 Sulfamethoxazole 963 Antibiotics Roxithromvcin No data available I Contrast medium lopromide 5386 I 3 Material and methods 3.1 Determination method Two different detection methods were used for the analysis of the above mentioned compounds. Ibuprofen, Diclofenac and Bezafibrate were separated and analysed by GC-MS detection after derivatisation with diazomethane and a clean up step by silica gel chromatography. LC-MS-MS was employed for the Transactions on Ecology and the Environment vol 65, © 2003 WIT Press, www.witpress.com, ISSN 1743-3541 276 Water Pollution \//I: Modclling, Mca~uringand Prediction analysis of Roxithromycine, Sulfamethoxazole, Carbamazepine, Diazepam and Ioprornide. Ionisation of the analytes was done by electrospray ionisation in positive mode. Prior to the sample extraction a surrogate standard ('josamycine, tylosine and dihydrocarbamazepine or meclofenamic acid) was added to the samples. Two different solid phase extraction phases (cyclohexane (CH)- and ENV+ - phase) were employed for LC-MS-MS sample preparation. The samples were acidified in the case of the C-18 and CH - solid phase extraction cartridges, whereas the addition of a neutral EDTA buffer solution was necessary for the ENV+ phase. The water samples were extracted and enriched by C- 18 solid phase cartridges prior to the analysis with GC-MS. To overcome problems due to ion suppression in the LC-MS method, recoveries of the surrogate standard and measurements of multiple dilutions of the extracts were performed. The limit of quantification (LOQ) was set with 20 ng/l and the detection limit (LOD) with 10 ngll. 3.2 Wastewater treatment plant and sampling 3.2.1 Wastewater treatment plant The investigated wastewater treatment plant (WWTP) serves a rural community in the South-East of Austria. The WWTP was designed for 7,000 population equivalents, whereas presently about 2,000 inhabitants are connected to the sewer system. The treatment plant is charged predominantly with domestic sewage from a separated sewer system without industrial influents and with strong seasonal fluctuations due to the local viniculture influence. Therefore it is typical for a wide range of WWTP realized