Factors Affecting Spatial and Temporal Concentration Variability of Pharmaceuticals: Comparison between Two WWTPs

The presence of emerging organic micropollutants (such as pharmaceuticals) in sewage has been, for a long time, an issue of great concern within the international scientific debate. This item represents one of the main challenges related to a sustainable development, with particular concern to the public health control. While most of the work has been concentrated on their detection and the evaluation of their average level, little is known about the spatial and temporal variability of concentrations of these compounds in the effluent and its capability to affect the concentrations in time of the receiving water body. In this study, three sampling campaigns were carried out at two different wastewater treatment plants (WWTPs) in Varese area (Northern Italy) with the aim of monitoring the occurrence of some pharmaceuticals to evaluate their removal efficiency. The detected pharmaceuticals were: Ofloxacin, Ibuprofen, Atenolol, Bezafibrate, Carbamazepine, Salbutamol, Cyclophosphamide and Hydrochlorothiazide. The results obtained, together with the analysis of the characteristics of the chemicals and of the two WWTPs, allowed evaluating the factors affecting the spatial and temporal concentration variability in effluent waters and the potential influence of this variability in driving the exposure of the aquatic ecosystems in the receiving water body.