Can antimony, arsenic, cadmium, lead, mercury, and nickel promote oxidative stress?

At environmentally and occupationally relevant exposures, antimony, arsenic, cadmium, lead, mercury, and nickel have convergent potential to disturb cellular redox balance. The overall claim is supported, with strongest evidence from mechanistic, experimental, and animal literature and more variable direct human evidence across individual elements.

Mechanistic evidence

• These elements can increase reactive oxygen species (ROS) through disruption of mitochondrial electron transport, electron leakage, and increased NADPH oxidase activity. Excess ROS relative to cellular antioxidant capacity is a core driver of oxidative stress and oxidative molecular damage.
• They can alter antioxidant defenses involving superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase. Reduced enzymatic ROS clearance shifts redox balance toward oxidation, although the measured direction and magnitude of enzyme changes depend on dose, tissue, timing, and metal species.
• Binding, oxidation, or depletion of glutathione (GSH) and protein cysteine thiols is another coherent pathway. Loss of available GSH weakens thiol-dependent antioxidant systems and can promote ROS accumulation—even for metals such as cadmium that are not themselves redox-active.

Human relevance

• Human observations are consistent with these mechanisms: among pregnant women in Bangladesh, urinary 8-oxodG was positively associated with urinary cadmium and arsenic; nickel–cadmium battery workers with higher exposure had elevated urinary oxidative-damage markers.
• These biomarkers indicate oxidative injury but are not specific to a single metal. Interpretation also depends on exposure speciation, biological matrix, co-exposures, and other determinants of oxidative stress.

Bottom line

• Antimony, arsenic, cadmium, lead, mercury, and nickel can promote oxidative stress through ROS generation, impaired antioxidant defenses, and disruption of glutathione/cellular thiols. The mechanistic basis is strong and convergent, while confidence in direct human characterization is moderate because evidence is less uniform—particularly for antimony and nickel.