Environmental performance assessment of global crop protection practice

Numerous challenges in achieving sustainability are associated with agricultural practices. It is pivotal to quantify and enhance the sustainability performance of agricultural production systems to effectively address these challenges. The use of chemical pesticides in current crop protection practices, aimed at ensuring food quality and safety, is linked to various impact challenges related to toxicity, particularly affecting non-target organisms in soil, air, and water. It is essential to evaluate the pesticides’ impact on ecosystems by characterizing application patterns at the appropriate level of detail, to combine these with environmental emissions and fate, and to assess related exposure and ecotoxicological effects. Identifying factors driving these impacts is crucial for minimizing chemical pollution related to crop protection products. The present PhD project “Environmental Performance Assessment of Global Crop Protection Practice” aims at creating a scientifically sound foundation for quantifying and evaluating performance baselines and identifying impact reduction options for different crop protection practices, with a focus on three main aspects: (1) Global pesticide use database: develop a globally consistent atlas of more than 1,000 pesticide active ingredients effectively applied across 130 crops and 180 countries between 2016 and 2020, considering information on application methods, crop growth stages, treatment target compartments, and uncertainty information, and imputing missing data using machine learning techniques. (2) Pesticide emission scenarios: provide mass balance-based estimates for pesticide emissions via drift deposition in comparative risk and impact assessment with consideration of drift validity ranges, spray nozzle positions, and drift reduction technologies, for integration into existing emission distribution models. (3) Global freshwater ecotoxicity impacts from pesticide use: develop a global screening assessment of ecotoxicity impacts from agricultural pesticide use combining in a consistent LCIA impact pathway approach application data with emission, multimedia fate, exposure, and effect modeling, and identify impact hotspots across pesticides, crops, and regions.

After an introductory chapter, the second chapter introduces an extensive and robust dataset on global pesticide use, offering comprehensive and granular coverage of pesticide usage worldwide. It details the strategic methodologies including data cleaning and harmonization, data imputation, and output generation for developing the global pesticide use database, including a thorough assessment of the mass of pesticides applied globally, the application rate (measured as mass applied per treated area per individual treatment), and the geographic distribution of pesticide usage. Additionally, this chapter conducts a comparative analysis with existing datasets on pesticide usage and anticipates future developments in the field.

The third chapter explores the concept of cumulative drift deposition as a means to characterize pesticide emissions. It provides an analysis of drift deposition fractions derived from contemporary drift functions, investigates the impact of buffer zones and spray nozzle positions, and evaluates the consequences of differing assumptions about drift deposition from the field edge to the lower validity limit. Furthermore, this chapter highlights the need for alternative approaches in subsequent research to improve the precision and practicality of drift deposition in emission modelling.

The fourth chapter outlines the journey of pesticides from application to their impacts on freshwater ecosystems. This includes emissions, their environmental fate, exposure pathways, and ecotoxicological effects. It offers a detailed exploration of impact pathway modeling, from gathering crucial input data to employing species sensitivity distributions for effect modelling. The chapter concludes by identifying and prioritizing pesticide application scenarios that result in significant environmental impacts. By taking a comprehensive view, it emphasizes the connections between the use of pesticides to their impacts, underlining essential measures for evaluating and reducing the adverse effects of pesticides on freshwater ecosystems.

In summary, the PhD project presents global pesticide usage and its environmental emissions, with enhancing the accuracy and reliability of environmental impact evaluations. The adoption of more detailed data, advanced modelling techniques, and comprehensive evaluations within the context of Life Cycle Assessment (LCA) frameworks promises to support more sustainable pest management practices worldwide, making contributions to reducing the environmental footprint of pesticide application.