Topic overview

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Pollutant-induced injury often involves excess reactive oxygen species, changes in gene expression, or disruption of essential enzymes and signaling systems. The lesson traces biotransformation from Phase I cytochrome P450 activity, which can generate reactive metabolites, through Phase II conjugation pathways that support detoxification. It examines AhR signaling and endocrine disruption, alongside specific effects of heavy metals, organophosphates and carbamates, air pollutants, and mitochondrial poisons. Persistent organic pollutants, redox cycling, and microplastics provide further examples of how exposure can affect cells. The topic also covers epigenetic modifications, biomarkers of exposure and effect, antioxidant defenses, and the Nrf2 pathway, bringing these mechanisms together in diagrams and a pollutant-mechanism summary table.