A novel proxy to assess the environmental fate and impact of complex (bio)pesticides: methodological development and challenges

The development of biocontrol products proceeds mainly through the proposed protocols to study their activity and their environmental fate and impact.Currently, half-life (DT50) is used in order to evaluate the environmental fate of synthetic pesticides. However, DT50 approach gives only information about pesticides' persistence in the environment, but no indications concerning the formation of degradation products or its impact on biodiversity are provided. Furthermore, biocontrol products are complex (bio)chemical mixtures. The DT50 is not applicable for such complex products. Therefore, novel analytical approaches should be considered in order to overcome these difficulties.A novel approach based on meta-metabolomics and Mass Spectrometry; the “Environmental Metabolic Footprinting” (EMF), was recently introduced [1-3]. It affords a novel universal and integrative proxy; the “resilience time”, dedicated to assess the environmental fate and impact of complex (bio)pesticides in environmental matrices (e.g. soil, sediment). Nonetheless, the development of such Mass Spectrometry-based untargeted meta-metabolomics approach is a challenging task. Several obstacles and difficulties must be addressed, such as dealing with large multifactorial experimental designs and complex environmental samples containing a wide biochemical diversity.The current presentation will expose the methodological development of this novel proxy, by highlighting the setup of the sample preparation, the collection of chemical information by extractions, and the development of the LC-HRMS analytical methods. This exposure will allow presenting and discussing the different challenges facing the promotion of this novel strategy, and the critical approaches that are used in order to accomplish its development and rendering it reliable and highly confident before suggesting it as an alternative tool to the classical concepts that are currently used for regulations guidelines.[1]: Patil et al. 2016. Sci. Total Environ. 566–567:552–558[2]: Salvia et al. 2018. Environ. Sci. Pollut. Res. 25(30):29841–29847[3]: Ghosson 2020. Thesis. Université de Perpignan