Which substance has a health limit of 10 mg/L due to potential adverse health effects?

Nitrate/Nitrite-N is associated with a health limit of 10 mg/L primarily because of its potential health risks, particularly for infants. High levels of nitrate can lead to a condition known as methemoglobinemia, or "blue baby syndrome," where the oxygen-carrying capacity of the blood is impaired. This condition can be especially dangerous for babies under six months of age, as their digestive system is more susceptible to converting nitrate to nitrite, which affects the hemoglobin in the blood.

Health guidelines, such as those set by the Environmental Protection Agency (EPA) and other health organizations, have established this limit to protect vulnerable populations, particularly infants. The limit is based on research that connects high nitrate concentrations in drinking water to serious health complications.

The other substances listed have different health considerations and regulations. While they may also have limits established for health reasons, none are specifically set at 10 mg/L due to the same acute health risks associated with nitrate.