Which contaminant in water is associated with methemoglobinemia?

Methemoglobinemia, often referred to as "blue baby syndrome," is a condition where hemoglobin is altered such that it cannot effectively carry oxygen. This condition is particularly associated with high levels of nitrates in drinking water. When ingested, nitrates can be converted into nitrites by bacteria in the gastrointestinal tract. Nitrites then react with hemoglobin to form methemoglobin, which is less effective at transporting oxygen. This is especially a concern for infants, as their bodies are more susceptible to this transformation.

Nitrates can enter water supplies through various means, including agricultural runoff, septic systems, and fertilizer application. Ensuring that water supplies are monitored and treated to reduce nitrate levels is essential in protecting public health, especially for vulnerable populations such as infants and pregnant women.