Ecotoxicity assessment of pesticide use: methodological and modeling advances in lca framework
- Autores: Nancy Ángela Peña Valbuena
- Directores de la Tesis: M. Asunción Antón Vallejo (dir. tes.), Peter Fantke (codir. tes.), Xavier Gabarrell Durany (tut. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Ralph Rosenbaum (presid.), Carlos Martínez Gasol (secret.), Christel Renaud-Gentié (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia y Tecnología Ambientales por la Universidad Autónoma de Barcelona
- Materias:
- Enlaces
- Resumen
Pesticides are applied to agricultural fields to protect and control crops from pests, disease and undesired weeds, to increase crop productivity and reduce blemishes, and their global use is substantial. Life Cycle Assessment (LCA) is a standardized methodology that can be applied to assess the environmental performance of different product and systems. In LCA, significant advances associated with the evaluation of the agricultural use of pesticides have been made during the past few years, and several approaches have been developed for taking the impacts of pesticide use on human health and ecosystems into account. However, including toxicity-related impacts for pesticide use in LCA is still associated with methodological limitations. Furthermore, considerations for assessing pesticides are currently affected by significant inconsistencies between the life cycle inventory analysis (LCI) and the impact assessment (LCIA) phases of LCA, and this poses as a practical challenge. This thesis, hence, aims to contribute, within the LCA framework, towards the improvement of consistent quantitative methodologies to assess emission fractions and ecosystem toxicity impacts of pesticide use.
One of the main challenges in LCA for agriculture is modeling pesticide emission fractions for the inventory analysis; there are very different approaches and assumptions to provide emission estimates, leading to inconsistent and non-comparable results. This challenge is addressed by testing the influence of the inventory model choice on the environmental performance profiles of different cropping systems. Furthermore, a simplified estimation routine for pesticide emission fractions is proposed, allowing practitioners to include the agricultural field on the assessment. The delineation between pesticide emission inventory and impact assessment has shown to have considerable influence on the estimation of ecotoxicity impacts; in this regard, this study takes advantage of the latest recommendations for pesticide emission inventory and impact evaluation, to frame a suitable interface for LCI modeling and LCIA characterization avoiding possible temporal overlaps.
Another methodological limitation associated with ecotoxicity impacts of pesticide use is how to account for inorganic fungicides in LCA studies involving agricultural systems. To address this, freshwater ecotoxicity impacts of copper-based fungicides were quantified and compared with the most common synthetic fungicides used against downy mildew on a practical case study. Soil ecotoxicity was characterized for specific soil chemistries and textures. To introduce spatial differentiation (critical aspect to describe the toxic effects of metal-based substances) in the ecotoxicity assessment, 7 European water archetypes and more than 15000 soils in three different application scenarios were evaluated.
To capture the complexity and variability of agricultural practices, while simplifying and facilitating the assessment for pesticide application, a series of archetype scenarios was established. These define specific combinations of pesticide target classes, crops and application methods, intended to estimate global emission fractions of pesticides in LCA. This task was conducted in the frame of the LCA pesticide consensus building effort. Finally, the consensual recommendations for simplification and aggregation across conditions are presented and illustrated with a practical example conducted as part of the present thesis.
Results in this thesis demonstrate the importance of considering pesticide use for ecotoxicity assessment in agricultural production and represents a relevant step towards methodological advances in quantifying pesticide emission fractions and their related potential impacts on ecosystems within the LCA framework. Among important follow-up lines of research, future work should focus on the inclusion of pesticide metabolites in the assessment of toxic impacts, the development of characterization factors to account for soil ecotoxicity and the further inclusion of metal emissions from agricultural practices (e.g., application of pesticides, manure and chemical fertilizers) into LCA.
