Water high in nitrates can cause which condition?

• A. Chlorosis
• B. Gastroenteritis
• C. Methemoglobinemia
• D. Arsenic poisoning

Answer: (C)

High nitrates in drinking water can form nitrites in the body, and nitrites convert hemoglobin into methemoglobin, which cannot carry oxygen effectively. Infants are especially vulnerable because their immature enzyme systems and gut bacteria facilitate this process, leading to methemoglobinemia, sometimes called “blue baby syndrome.” Symptoms include a bluish or pale skin tone, rapid breathing, and fatigue. The other conditions listed don’t arise from nitrate exposure in water: chlorosis relates to iron deficiency anemia, gastroenteritis is an infection of the digestive tract, and arsenic poisoning comes from arsenic exposure. Preventing methemoglobinemia focuses on providing water with low nitrates and, if needed, treating exposure promptly (in severe cases, methylene blue may be used).