Evaluating the ecotoxicity of agropesticides and environmental water contaminants using cell-line and zebrafish embryonic assays

Pesticides are an indispensable part of agriculture in the modern day to enhance crop yield and pest control. Despite increasing recognition of the health and environmental hazards derived from these complex chemical mixtures, approval of agrochemical products is mostly dependent on the toxicity of individual components, disregarding potential combined effects. The objective of the study was to assess the toxicity of common commercial agropesticides using both cell-line and zebrafish embryonic assays as model organisms, as well as briefly evaluate environmental waters in agriculture-dominated sites using Chiang Mai, Northern Thailand as a case study. The results showed that the pesticides tested exhibited acute lethality and sublethal effects on the model organisms tested, albeit some to a lesser extent than previously reported findings on single active compounds. Our findings also revealed challenges in using a single broad-spectrum solid-phase extraction method to retain pesticide analytes due to their chemical complexity. Nonetheless, the study presents a holistic workflow in assessing the ecotoxicity of environmental water samples. The water samples from Chiang Mai significantly induced endocrine responses in both assays, with transcriptome data indicating deregulation in major developmental gene expression pathways after a 96h exposure. These findings confirm the presence of contaminants in the aquatic environment of agriculture-dominated regions, which can potentially alter physiological development in exposed organisms and decrease overall fitness. We recommend that all pesticide formulations be fully considered in authorization processes and structured environmental monitoring schemes be developed to mitigate the negative impacts of agrochemicals on both human health and ecosystem stability.Bachelor of Science in Environmental Earth Systems Scienc