Water Journal : Water Journal July 2012
wastewater refereed paper 84 JULY 2012 water technical features Abstract The detection of an ever-increasing number of pharmaceutical contaminants throughout the water cycle has raised scientific and public concerns regarding their potential impact on the environment and on human health. With that regard, hospital wastewater is often suspected of being a major source of pharmaceutical residues in municipal wastewater and, as such, should be treated prior to discharge. But are such suspicions truly founded? To answer this question, the Urban Water Security Research Alliance project on Hospital Wastewater investigated the contribution of six hospitals located in South-East Queensland (SEQ) to the loads of 589 pharmaceuticals in municipal wastewater using a predictive consumption-based approach. In addition, the possibility that hospital-specific substances are present at levels that may pose a risk for human health was evaluated. The results suggest that the contribution of hospitals towards the total load of pharmaceuticals in the influent of sewage treatment plants (STP) and risks of human exposure to the pharmaceuticals exclusively administered in the investigated hospitals are limited. The study concludes that decentralised wastewater treatment at the sites investigated would not have a substantial impact on pharmaceutical loads entering STPs and, finally, the environment. Introduction The incessant improvement of analytical equipment over the past 20 years has allowed the detection of more and more pharmaceutical compounds such as antibiotics, analgesics, antidepressants, antineoplastics, beta-blockers and X-ray contrast media at increasingly lower concentrations (down to ng L-1) in municipal wastewater, ground and surface waters and, more recently, drinking water (Fick et al., 2009; Metcalfe et al., 2010; Vulliet et al., 2011). Consequently, the emergence of such contaminants has raised concerns not only for the scientific community, but also for the water industry and the general population, as these substances are originally designed to be biologically active and could potentially cause adverse effects on aquatic life and human health (Monteiro and Boxall, 2010). The presence of pharmaceutical residues in the aquatic environment primarily originates from the discharge of treated municipal wastewater. Sources of pharmaceuticals in municipal wastewater include excretion from humans (Sanderson et al., 2004) and improper disposal of unused medicines (Watts et al., 2007). Agriculture and industries also contribute to pharmaceutical pollution in the environment (Kümmerer, 2004). Finally, in numerous countries, including Australia, untreated hospital wastewater is discharged to STPs along with domestic wastewater. Due to their activities, hospitals release high concentrations of various pharmaceuticals and numerous pathogens in their effluent (Thomas et al., 2007; Jury et al., 2011). Therefore, it is not surprising that they are often seen as major point sources of pharmaceuticals in municipal wastewater (Hawkshead, 2008). Although the decentralised treatment of hospital wastewater has often been proposed as a solution to reduce pharmaceutical inputs to STPs, recent studies concluded that this would have limited impact on the reduction of pharmaceutical residues in municipal wastewater. In these studies on the characterisation of hospital wastewater in Europe and Australia, the contributions of hospitals were limited, with values under 15% (Thomas et al., 2007; Ort et al., 2010). Such studies are, however, based on results obtained for a limited number of experimentally measurable substances, while hundreds of various pharmaceuticals are consumed in hospitals and may be of greater concern than the one currently analysed for. Prior to field measurements, it is necessary to identify and quantify pharmaceuticals of concern and to determine if pharmaceuticals exclusively used in hospitals should receive priority attention when compared to pharmaceuticals used by the general population. For this purpose, a prioritisation tool based on pharmaceutical consumption data at six hospitals located in SEQ was developed. This tool allowed the prediction of the contribution of these hospitals to the loads of 589 pharmaceuticals in municipal wastewater, hence identifying compounds for which hospitals would be a major contributor. Pharmaceuticals exclusively used in hospitals (i.e. returning a 100% contribution) were further screened by predicting their concentration in both hospital wastewater and influent of the corresponding STP to evaluate their possibility to be present at levels that may pose a risk for human health. Methodology Hospitals investigated The six hospitals selected are public hospitals located in three distinct catchments, with populations ranging from 45,000 inhabitants in the catchment where the Caboolture Hospital (CAB) is located, up to 572,000 inhabitants in the catchment including the Prince Charles (PC), Princess Alexandra (PA) and Royal Brisbane and Women's (RBWH) Hospitals (Figure 1). QEII Hospital is the smallest of the six hospitals, with a total number of 132 beds. The general and teaching hospital, RBWH, is the largest hospital with 882 beds. The volumes of water consumed at these two hospitals KS Le Corre, J Keller, C Ort A project investigated the contribution of six hospitals in South-East Queensland PHARMACEUTICAL RESIDUES IN MUNICIPAL WASTEWATER: ARE HOSPITALS A MAJOR POINT SOURCE?
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