What syndrome can excessive nitrates in drinking water cause in infants?

The correct answer is blue baby syndrome, which arises from excessive nitrates in drinking water, particularly affecting infants. Nitrates can be converted into nitrites in the gastrointestinal tract. In babies, nitrites interfere with the ability of hemoglobin in the blood to carry oxygen. This results in a condition called methemoglobinemia, where a significant portion of hemoglobin loses its ability to bind to oxygen, leading to a bluish discoloration of the skin, particularly around the lips and limbs—hence the term "blue baby syndrome."

Infants are especially vulnerable because their stomach acid levels are lower than in older children and adults, allowing for the higher conversion of nitrates to nitrites. This condition can lead to serious health issues, including hypoxia (lack of oxygen). Identifying the presence of nitrates in drinking water is crucial for preventing this serious syndrome.

Other options do not relate to this specific health issue caused by nitrates. Pneumonia syndrome, dehydration syndrome, and respiratory syndrome are not directly linked to nitrates in drinking water and do not demonstrate the same physiological response that is characteristic of blue baby syndrome.