Atrazine Pollution: Causes, Impacts, and the Use of Biomarkers in Non-Target Organisms to Assess Environmental and Health Risks

Atrazine (ATZ) is one of the most widely used herbicides worldwide and remains an environmental concern due to its persistence, mobility, and recurrent detection in soil, surface water, groundwater, and biota. This narrative review examines and discusses the environmental occurrence, exposure pathways, ecotoxicological effects, and major mechanisms underlying ATZ toxicity in non-target organisms, with particular emphasis on biomarker-based assessment. Despite extensive research on ATZ, available knowledge remains largely compartmentalized by environmental process, toxicological mechanism, biological endpoint, or taxonomic group, and comparatively few studies integrate environmental exposure with mechanisms of toxicity and associated biomarker responses across multiple taxa and levels of biological organization. Available evidence indicates that ATZ toxicity involves interconnected mechanisms, including oxidative stress, endocrine disruption, neurotoxicity, genotoxicity, mitochondrial dysfunction, inflammation, and cell death. These mechanisms result in molecular, biochemical, histopathological, reproductive, developmental, and behavioral alterations across plants, invertebrates, fish, amphibians, and mammals. Biomarkers of oxidative stress, such as malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT), together with acetylcholinesterase activity (AChE), endocrine endpoints, micronuclei, comet assays, histopathological alterations, and gene-expression markers, have demonstrated value for detecting sublethal effects and elucidating mechanisms of toxicity related to ATZ exposure. However, interspecies variability, environmental factors, and the limited specificity of individual biomarkers highlight the need for integrated multibiomarker approaches combined with chemical analyses of ATZ. Overall, integrating environmental monitoring with mechanistically informative biomarkers may improve ecological and human-health risk assessment and provide stronger scientific support for surveillance programs and future regulatory decisions.