eng pesticide pollutants; metolachlor; toxicity. 2025 info:eu-repo/semantics/article Toxicological risks pediction of the metolachlor herbicide as environmental contaminant Faculty of Agriculture, University of East Sarajevo, Republic of Srpska, Bosnia and Herzegovina https://unilib.phaidrabg.rs/o:8514 ISBN: 978-99976-070-5-8 Proceedings - XVI International Scientific Agricultural Symposium “Agrosym 2025” Jahorina, October 2-5, 2025, Bosnia and Herzegovina startpage: 644 endpage: 648 Herbicide application has undeniably enhanced agricultural productivity, but it also carries significant environmental and human health hazards because of its inherent toxicity and longterm persistence. This study set out to characterize metolachlor’s toxicokinetic profile, including sensitive groups such as pregnant women after ingestion of contaminated water, and to predict its toxicity in aquatic species. We used OPERA-derived physiologically based toxicokinetic (PBTK) models to simulate metolachlor distribution in human tissues based on surface water concentration (45.5 μg/L) measured in 2018 at the Markovicevo monitoring site on Brzava River, which was the highest reported metolachlor content found during 2016-2022 among all surface water profiles in Serbia. Chemical toxicity was forecasted with ProTox-3.0, while acute aquatic toxicity endpoints were estimated via multiple linear regression in the SILIS-PTOXRA platform. Standard PBTK modeling indicated peak accumulation in the gastrointestinal tract (0.4062 mg/L) and liver (0.3392 mg/L), suggesting potential hepatotoxicity. Fetal PBTK simulations for pregnant and breastfeeding women predicted slightly lower tissue concentrations 0.297 mg/L in the gut and 0.2721 mg/L in the liver, yet still within a concerning range. Predicted toxicity profiles showed that Zebrafish embryos and larvae experience high mortality at 48 and 96 hours of exposure, shifting to moderate toxicity by 120–132 hours. In contrast, the freshwater crustacean Thamnocephalus platyurus exhibited only moderate acute sensitivity. These results underscore the pressing need for more comprehensive monitoring of pesticide contamination and for further research into the human health implications of long-term exposure to metolachlor-tainted water. All rights reserved application/pdf 1548064 bytes Mitrović, Tatjana Perović, Marija Obradović, Darija Lazović, Saša