What is the effect of excess nitrate in drinking water?

Excess nitrate in drinking water poses significant health risks, particularly to infants, making this the correct answer. Nitrate is converted to nitrite in the body, which can interfere with the oxygen-carrying capacity of hemoglobin, leading to a condition known as methemoglobinemia or "blue baby syndrome." This condition is particularly dangerous for infants under six months old, as their bodies are less equipped to handle high levels of nitrite. The potential for such serious health impacts emphasizes the importance of monitoring and controlling nitrate levels in drinking water to safeguard public health, especially for vulnerable populations like young children. This understanding is critical for anyone involved in water quality management and distribution.