Which body organ can be irreparably damaged by exposure to mercury?

The correct answer is the kidney, which is particularly at risk for irreparable damage from exposure to mercury. The kidneys play a crucial role in filtering and removing waste products from the blood, and they are highly susceptible to the toxic effects of heavy metals, including mercury. When mercury enters the body, it can accumulate in kidney tissue, leading to nephrotoxicity, which can interfere with normal kidney function and ultimately result in conditions like acute kidney injury or chronic kidney disease. This damage is often irreversible, making it vital to limit exposure to mercury to protect renal health.

In contrast, while the brain can also suffer severe damage from mercury exposure, particularly in terms of neurodevelopmental effects and neurotoxicity, the kidneys are specifically noted for their capacity to be irreparably harmed. The lungs can experience short-term damage from inhaling mercury vapors, but this damage is typically not as long-lasting as the effects on the kidneys. The stomach may be affected by mercury if ingested, but it does not generally lead to permanent damage like that seen with kidney exposure. Thus, the kidneys' particular vulnerability to the toxic effects of mercury makes them the correct answer in this scenario.