What health issue is associated with nitrate contamination?

• A. Liver cancer
• B. Blue baby syndrome
• C. Kidney stones
• D. Iron deficiency anemia

Answer: (B)

Nitrate in drinking water is linked to a health issue in infants called blue baby syndrome, which is methemoglobinemia. When nitrates are ingested, they can be converted to nitrites in the infant gut. Nitrite oxidizes the iron in hemoglobin from the ferrous (Fe2+) to the ferric (Fe3+) state, forming methemoglobin. Methemoglobin can’t bind and transport oxygen effectively, so the blood’s oxygen delivery drops, causing a bluish tint to the skin and mucous membranes in young infants. Babies are especially vulnerable because their gut conditions and red blood cells make this conversion more likely.

The other options don’t reflect a direct outcome of nitrate contamination. Liver cancer isn’t a typical result of drinking-water nitrate exposure, kidney stones aren’t caused by nitrates, and iron deficiency anemia arises from iron intake or loss issues rather than nitrate contamination.