What is the acute effect of exposure to elemental mercury?

The acute effect of exposure to elemental mercury is primarily pneumonitis, which is an inflammation of the lung tissue typically resulting from inhaling mercury vapors. When elemental mercury is inhaled, it can quickly convert to a toxic form that irritates the respiratory tract, leading to symptoms such as coughing, difficulty breathing, and chest pain. In severe cases, it can result in acute respiratory distress and respiratory failure.

The other options involve effects that are either incorrect or not as directly associated with acute exposure to elemental mercury. For instance, peripheral nervous system damage, while a potential long-term consequence of mercury exposure, is not typically considered an acute effect. Lead poisoning is unrelated, as it results from exposure to lead, not mercury. Skin irritation can occur from contact with mercury compounds but is generally not the primary acute effect when considering inhalation exposure. Thus, pneumonitis stands as the most relevant and immediate serious effect associated with elemental mercury exposure.