Benzo[a]pyrene as a Model Toxicant from Coal Mining: Impacts on Freshwater Fish Physiology and Ecosystem Health

Abstract

Coal mining activities release various contaminants into aquatic ecosystems, including polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (B[a]P), which are of particular concern because of their persistence and toxicity. This review examines B[a]P as a model toxicant, detailing its environmental entry routes and effects on freshwater fish. We emphasize the current knowledge on the molecular mechanisms of B[a]P-induced toxicity, focusing on oxidative stress, DNA damage, and histopathological alterations across multiple organ systems. Species- and tissue-specific responses of various fish are discussed, highlighting the complex interplay between the exposure conditions and biological outcomes. This review also explores the application of diverse biomarkers, including biochemical, histological, and molecular endpoints, for assessing fish health in coal-impacted ecosystems. Emerging technologies, such as omics approaches and non-invasive sampling methods, have been evaluated for their potential to enhance environmental monitoring capabilities. By integrating the findings from laboratory and field studies, this review provides a comprehensive overview of the sublethal physiological effects and ecological consequences of acute and chronic B[a]P exposure in aquatic ecosystems affected by mining. This analysis offers insights into evidence-based management strategies and underscores the need for ongoing monitoring to protect freshwater biodiversity in coal mining regions worldwide.