Fate, modeling, and risk of pharmaceuticals in wastewater treatment plants and Iberian rivers

• Autores: Victoria Osorio Torrens
• Directores de la Tesis: Sandra Pérez Solsona (dir. tes.), Mercè Granados i Juan (dir. tes.), Damià Barceló i Cullerés (dir. tes.)
• Lectura: En la Universitat de Barcelona ( España ) en 2015
• Idioma: inglés
• Tribunal Calificador de la Tesis: Nikolaos Thomaidis (presid.), Santiago Esplugas Vidal (secret.), Yolanda Picó García (voc.)
• Materias:
  • Química
    • Química analítica
      • Análisis cromatográfico
      • Espectroscopia de masas
• Enlaces
  • Tesis en acceso abierto en:  TDX  Dipòsit Digital de la UB 
• Resumen

  • In view of the concerns about the presence of pharmaceuticals in the aquatic environment, two main lines of research regarding these substances were followed within this thesis: Their fate was assessed along waste water treatment plants (WWTPs) and Iberian River basins. Their potential ecotoxicological risks to non-target aquatic organisms were evaluated. On this basis, the more specific objectives and the subsequent findings achieved within this thesis are reported as follows: I. The fate and behavior of pharmaceuticals under nitrifying activated sludge treatment in WWTPs and after their release into receiving surface waters (SW) via wastewater (WW) effluent discharge were studied. To that aim, a sensitive analytical protocol based on off-line SPE-LC—MS/MS was developed and validated for the simultaneous determination of diclofenac their metabolites and their transformation products (TPs) in WW. The method was further optimized and validated for additional analysis of sulfamethoxazole and its TPs in WW and SW. The method was applied to the analysis of WW and SW reporting the occurrence of the metabolites and TPs of diclofenac and sulfamethoxazole in the ng L-1 range. Additionally, the microbial mediated biotransformation of diclofenac and other related pharmaceutical structures into nitro and nitroso derivates in the nitrifying activated sludge was investigated. The use of HR-MS/MS allowed the identification of tentative chemical structures of nitrosation/nitration TPs confirmed for all compounds to generate via biotic mechanisms. II. Afterwards, the presence of a list of up to 96 selected pharmaceuticals in SW and sediments from four Iberian River basins characterized by high anthropogenic pressure was assessed. To that, the spatial and temporal distribution of pharmaceuticals were evaluated. pharmaceuticals were widespread and pseudo-persistent micropollutants in the Iberian aquatic environment. Concentration of pharmaceuticals in SW varied from the low to high ng L-1 range; while in sediments they were at the low ng g-1 level. Analgesics/antiinflammatories were the most relevant therapeutic group in SW; while for sediments these were antibiotics. Factors affecting their occurrence (i.e. hydrological conditions and human and animal uses) were also assessed by the application of modeling approaches and statistical tools. Overall, response of pharmaceuticals to river flow was negative, principally due to expected dilution effects. A “plug-flow” model approach was successfully applied to describe the fate of 14 selected pharmaceuticals in terms of attenuation downstream the water course of their main emission source considered as the WWTPs. Significantly positive relationships were found among levels of pharmaceuticals and population density and livestock units in both SW and sediment matrices, thus responding to the anthropic pressures in the catchments. III. Finally, this thesis contributed to the knowledge about the ecotoxicological risk of pharmaceuticals to aquatic ecosystems. To that, individual and combined acute toxicity of pharmaceuticals and other relevant micropollutants to D. magna and V. fischeri were assessed. Individual pharmaceuticals and TPs did not showed acute toxicity to the target aquatic organisms. However PhACs and TPs displayed synergistic effects in mixtures with other toxicants of the same environmental compartments. Additionally, an ecotoxicological risk assessment of 55 pharmaceuticals to D. magna, V. fischeri and fish along four Iberian River basins was conducted. The extensive data presented on the predicted ecotoxicological risk and the computation of pharmaceuticals relative contribution to the whole toxicity of the sample, provided valuable information for further prioritization exercices in the risk assessment of Spanish river basins. Then, the impact of changing pharmaceuticals levels and water flow conditions on the structure and function of river biofilms was studied. PhACs affected the structure and functioning of fluvial biofilms. The biotic response to the two main stressors studied PhACs and hydrology, varied among the different biofilm compartments (photoautotrophs and bacteria).