Editorials & Other Articles

Heading out for breakfast one morning, there was a sign outside the bathrooms that patrons should not drink the tap water. In particular, they should not use the tap water for formula for infants, since heavy nitrate concentrations in the water produced blue baby syndrome . .

Or, to be more specific:

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Methemoglobinemia can be acquired or congenital. It occurs when the iron in hemoglobin is oxidized from Fe2+ to Fe3+, leading to poor binding of oxygen. Additionally, the oxygen that is already bound is held more tightly to the hemoglobin due to a higher affinity, resulting in less oxygen delivery. A methemoglobin level > 1.5 g/dL causes cyanosis. The most common congenital cause is a deficiency in the enzyme cytochrome b5 reductase which reduces methemoglobin in the blood.[22]

However, in infants the most common cause of methemoglobinemia is acquired through the ingestion of nitrates (NO−3) through well water or foods. Nitrites (NO−2) produced by the microbial reduction of nitrate (directly in the drinkwater, or after ingestion by the infant, in his digestive system) are more powerful oxidizers than nitrates and are the chemical agent really responsible of the oxidation of Fe2+ into Fe3+ in the tetrapyrrole heme of hemoglobin.

Infants younger than 4 months are at greater risk given that they drink more water per body weight, they have a lower NADH- cytochrome b5 reductase activity, and they have a higher level of fetal hemoglobin which converts more easily to methemoglobin. Additionally, infants are at an increased risk after an episode of gastroenteritis due to the production of nitrites by bacteria.[22] The sources of nitrate can include fertilizers used in agricultural lands, waste dumps or pit latrines.[23] For example, nitrate levels are subject to monitoring to comply with drinking water quality standards in the United States and other countries.[24][25] The link between blue baby syndrome and nitrates in drinking water is widely accepted, but as of 2006 some studies indicated that other contaminants or dietary nitrate sources, might also play a role in the syndrome.[26][27][28]

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https://en.wikipedia.org/wiki/Blue_baby_syndrome