Assessing freshwater ecotoxicity of agricultural products in life cycle assessment (LCA): a case study of wheat using French agricultural practices databases and USEtox model

PURPOSE: A life cycle assessment (LCA) was conducted on winter wheat, based on real agricultural practices databases, on a sample divided into four production scenarios. The main objectives of this study are (1) to assess the environmental impact of winter wheat, using an LCA covering field practices, and the transport and storage of grain until it is sold to a miller; (2) to use the USEtox model (Rosenbaum et al. in Int J Life Cycle Assess 13:532–546, 2008) to assess the part of the total freshwater ecotoxicity impact due to pesticide use, its variability among plots, and to identify the active ingredients with the strongest impact; (3) and with the help of fungicide, insecticide, herbicide experts, to identify active ingredients to replace these high-impact pesticides and estimate the effect of such a substitution on total freshwater ecotoxicity. MATERIALS AND METHODS: InVivo (the authors’ company) is a French union of agricultural cooperatives that produces and sells, amongst other products and services, decision-making tools to help farmers manage fertilization and pesticide applications. With the help of cooperatives and with the help of these tools, pedologic, climatologic and agronomic (in particular for fertilization and pesticide applications practices) data can be collected for each agricultural plot of a farm. RESULTS AND DISCUSSION: The main conclusions of this study are that : (1) when considering freshwater ecotoxicity impacts, pesticide use is predominant on the whole life cycle of winter wheat, (2) there is a huge scattering of the results observed between fields when compared to the low scattering of the results between the four production scenarios, (3) it is feasible, with the USEtox model, to identify the active ingredients with the strongest impact and to potentially decrease this average impact by 50% by substituting only three active ingredients. CONCLUSIONS: A further step to improve ecotoxicity assessment in LCA would be to develop a model to better estimate the pesticide emissions pattern on field, taking into account pedo-climatic conditions and farmers’ practices.