What condition is caused by high levels of nitrates in drinking water, particularly affecting infants?

High levels of nitrates in drinking water can lead to a condition known as methemoglobinemia, particularly in infants. This condition occurs when nitrates are converted into nitrites in the body, which then react with hemoglobin to form methemoglobin. Unlike regular hemoglobin, methemoglobin cannot effectively transport oxygen in the bloodstream, leading to reduced oxygen delivery to the body's tissues. Infants are especially vulnerable because their digestive systems convert nitrates to nitrites more readily, and their lower body mass exacerbates the potential impact.

Methemoglobinemia is critically dangerous for infants as it can result in symptoms such as a bluish discoloration of the skin, known as cyanosis, which indicates low oxygen levels. Immediate medical attention is typically required when methemoglobinemia is suspected to prevent serious complications.

In contrast, respiratory distress, lead poisoning, and acidosis are not directly caused by high nitrate levels in drinking water. Respiratory distress is often associated with respiratory issues unrelated to nitrate exposure, lead poisoning stems from lead contamination rather than nitrates, and acidosis is a broader term for increased acidity in the body that can arise from various metabolic or respiratory disorders but does not directly link to nitrate levels in drinking water.