A look to surface water and wastewaters in Beira Baixa, Portugal: wastewater treatment plants and environmental risk

The presence of pharmaceutical active compounds (PhACs) in environmental samples is of great concern. Most of these compounds come from wastewater treatment plants (WWTPs) due to the ineffectiveness of the treatment. Therefore, evaluating the removal efficiency of conventional wastewater treatments is mandatory to eliminate or reduce the concentration of PhACs from the WWTP effluents and, more importantly, to assess these target residues' impact in the receiving waters. This work quantifies twenty-six PhACs in the influents and effluents of five conventional WWTPs in Beira Baixa (Portugal) and their corresponding receiving waters. The results indicate concentration levels in the range of 0.03-348 mu g L-1, 0.04-84.8 mu g L-1, and 0.04-5.26 mu g L-1 from influents and effluents WWTPs and receiving waters, respectively. The environmental risk posed by PhACs was assessed by means of risk quotients (RQs) at four trophic levels. Several target PhACs showed RQs values close to one for some trophic levels. Especial attention should be paid to antibiotics such as erythromycin and clarithromycin since their risk quotients in downstream samples revealed that they could pose an ecotoxicological risk to algae.