Multimedia fate modelling and impact of pharmaceuticals compounds on freshwater
- Autores: Sergio Alberto Cruz Monteiro de Morais
- Directores de la Tesis: Xavier Gabarrell Durany (dir. tes.), Cristina Maria Fernandes Alvim Delerue Matos (codir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2014
- Idioma: inglés
- Tribunal Calificador de la Tesis: Damiá Barceló Culleres (presid.), M. Asunción Antón Vallejo (secret.), António Manuel Antunes Fiúza (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TESEO
- Resumen
The overall objective of this dissertation is to contribute to the development of best available practices in environmental multimedia fate and effect modelling for ecosystem impacts assessment of pharmaceutical compounds. The distribution of pharmaceuticals through several environmental media poses a potential toxic hazard to freshwater ecosystems, among other endpoints. The ionising properties of pharmaceuticals represent additional challenges when modelling the multimedia fate, exposure, and effect of this class of chemicals. Large uncertainties are expected when modelling the mobility, as well as the bioavailability for uptake by exposed biota and degradation, of ionising organic chemicals using conventional models. The development and evaluation of alternative approaches that include these issues are essential for the improvement of micropollutants environmental behaviour simulation. Model comparison and quantification of uncertainties of model results are vital for their correct interpretation. Furthermore, the quantification of uncertainties of model results is detrimental to establish priorities for further monitoring, as well as research, the wide number of pharmaceutical active compounds currently in use considering the most important pathways of environmental contamination.
In order to achieve that, the following specific objectives are addressed: 1. Develop a consistent matrix algebra framework for multimedia fate, multipathway exposure and toxicity effects models adapted for pharmaceutical compounds and consistent with life cycle impact assessment models.
2. Develop an approach to quantify the uncertainty of model results, accounting for regression model uncertainty, and identifying the main contributing parameters to overall uncertainty.
3. Compare and quantify the uncertainty of alternative model approaches on the level of characterisation factors as well as of final impact results, contributing to the identification of the best available practices on multimedia fate, exposure and effect modelling of PCs based on current scientific knowledge.
4. Prioritise pharmaceutical compounds on their probabilistic impact on freshwater ecosystems from both WWTP direct emissions and indirect emissions for further monitoring and research.
Chapter 1 puts this dissertation into its context and defines its objectives.
Chapter 2 presents a multimedia fate, exposure, and effect model based on matrix algebra adapted for pharmaceutical compounds and consistent with the UNEP/SETAC consensus model USEtox. An approach to quantify the uncertainty of model results using Monte Carlo analysis is presented. The approach accounts for the uncertainty of regression models and toxicity effects, as well as the variability of environmental parameters and experimental parameter values. The framework is applied to pharmaceuticals detected in biosolids following application on agricultural soils. The most influential parameters of the probabilistic comparative impact assessment were identified, as well as topics for further research for the compounds of most concern.
Chapter 3 is a detailed comparison of the USEtox model with the alternative framework adapted for pharmaceutical compounds. The alternative framework includes regressions to estimate fate parameters that account for the ionized fraction of a molecule. The comparison has been performed at the level of characterisation factors as well as of final impact results for 3 emissions scenarios into different environmental media. The most sensitive model parameters in the estimation of ecotoxicological characterization factors of micropollutants were evaluated by Monte Carlo analysis in both the default USEtox model and in the alternative approach.
Chapter 4 and 5 present a prioritisation of PCs detected in European wastewater treatment plants for further monitoring and research. Chapter 4 presents the pathway of direct discharge of WWTPs emissions to surface waters. In Chapter 5 the indirect emissions pathways to the freshwater compartment are addressed. The indirect emission pathways include the application of biosolids from WWTPs and of effluents as reclaimed water for irrigation, both on agricultural areas and landscapes. Research topics were defined by indentifying important gaps of knowledge as well as by computing the contribution of estimated model parameters¿ uncertainty to the impact variance.
Chapter 6 presents general conclusions on the research outlined and will provide recommendations for future research.
