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Advancing Detection Strategies for Emerging Pesticides in Surface Waters

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posted on 2024-06-17, 03:31 authored by Pulasthi Serasinghe
Recent advancements in pesticide development have led to the emergence of bioactive compounds, posing potential risks to non-target organisms and ecosystems. Despite global monitoring initiatives, deficiencies in sampling, analysis, and risk assessment hinder the identification of novel pesticides and associated risks. This research addresses these challenges through a comprehensive approach, integrating innovative sampling techniques and robust analytical methodologies. Chapter 2 served as a foundational element, providing a detailed literature review. It began with an examination of emerging pesticides approved for use in Australia, addressing associated concerns and constraints within the regulatory process. The chapter then transitioned to environmental water monitoring, delving into the significance of passive sampling technology for pesticide surveillance in aquatic systems, along with an assessment of its various designs and limitations. The latter sections concentrated on sampling and extraction techniques in chromatographic analysis. The chapter concluded with an evaluation of chromatographic techniques and the potential of high-resolution mass spectrometry for environmental pesticide monitoring. Through this, Chapter 2 not only provided a succinct overview of the current landscape but also guided the development of effective methodologies in subsequent chapters. In Chapter 3, a novel method prioritised pesticides for monitoring by combining registration data with laboratory monitoring capacity. Applied in Victoria, Australia, this approach identified 144 pesticides, emphasizing the need to broaden monitoring beyond traditional categories. The study introduced a refined prioritization model that considers both potential toxicity to local ecosystems and the likelihood of local usage, serving as a practical starting point for environmental practitioners and researchers. This method supports a periodic prioritization model that enables the continuous identification of new pesticides, aligning with the evolving landscape of pesticide products and catchment land-use activities. Chapter 4 validated the prioritization method in Greater Melbourne, employing passive sampling devices and suspect screening via ultra high-performance liquid chromatography (UPLC)-high resolution mass spectrometry (HRMS). This approach effectively identified 21 potential pesticides, confirming the presence of five emerging pesticides in Australian surface waters for the first time. The study highlights the efficacy of passive sampling in detecting sporadic pollution, covering a range of polarities, and offering a valuable alternative to conventional methods like grab sampling. The integration of HRMS technology in a suspect screening approach proves robust and efficient for screening numerous potential pesticides in environmental water monitoring and risk assessment programs. Chapter 5 delved into the seasonal occurrence of fungicides within the Greater Melbourne area (GMA), emphasizing the impact of weather events on pesticide transport. The study recommends thorough monitoring before and after significant rainfall events to enhance understanding of novel fungicide behaviour within surface water systems. The findings underscore the importance of continuous and long-term monitoring of recently registered fungicides, considering their potential impact on aquatic organisms. Chapter 6 introduced a novel analytical method based on Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction and UPLC tandem mass spectrometry (MS-MS), to accurately quantify four novel fungicides in surface water systems at environmentally relevant concentrations. The method's sensitivity, precision, and repeatability are demonstrated through validation, emphasizing its reliability for environmental analysis. Application of the method to real-world surface water samples from Greater Melbourne reveals varying concentrations of the detected fungicides, with notable implications for environmental impacts and potential risks to non-target aquatic organisms. The hybrid approach of passive sampling, grab water sampling, and advanced analytical techniques, as demonstrated in Chapters 4, 5, and 6, enhances the understanding of pesticide occurrence in regional surface water systems. Insights from these chapters underscore the need for continuous and long-term monitoring, especially for recently registered pesticides, contributing to robust ecological risk assessments. My research proposes a proactive monitoring framework, periodically aligning with new pesticide approvals, and emphasizes the importance of global collaboration and data sharing for comprehensive risk assessments. Future recommendations include refining prioritization methodologies, optimizing passive sampling techniques, and further improving analytical capacities for detecting novel pesticides. Overall, this research contributes valuable insights to the field of pesticide monitoring in surface waters and lays the foundation for effective environmental management and regulatory initiatives.

History

Degree Type

Doctorate by Research

Copyright

© Pulasthi Serasinghe 2024

School name

Science, RMIT University