Which demographic is most vulnerable to the effects of high nitrate levels in water?

Children under five years of age are particularly vulnerable to the effects of high nitrate levels in water due to their developing bodies and higher metabolic rates. Nitrate can cause a condition known as methemoglobinemia, or "blue baby syndrome," which affects the ability of blood to carry oxygen. Infants and young children have less mature digestive systems, making them more susceptible to the conversion of nitrate to nitrite, which disrupts oxygen transport in the bloodstream.

While other demographic groups may also experience negative impacts from high nitrate levels, children under five are specifically at heightened risk due to their physiological differences and developmental stage. Pregnant women, senior citizens, and individuals with chronic illnesses can have varying degrees of susceptibility, but the immediate and drastic effects on young children make them the most vulnerable group in this context.