Which primary inorganic contaminant poses an immediate health risk?

Nitrates can pose significant health risks, especially for vulnerable populations such as infants. When consumed in high quantities, nitrates can convert to nitrites in the body, leading to methemoglobinemia or "blue baby syndrome." This condition affects the ability of blood to carry oxygen, which can be life-threatening for young children.

While lead, arsenic, and mercury are also serious contaminants that can have long-term health effects, their immediate health risks are not as pronounced as those associated with high nitrate levels in drinking water, particularly for young children. Lead exposure can lead to developmental issues, arsenic is linked to various cancers and skin lesions, and mercury can affect the nervous system. However, the acute risk associated with high nitrate concentrations can lead to immediate health crises, especially in infants, making it a priority for water quality monitoring.