Which phenomenon is caused by elevated levels of nitrates in drinking water?

Elevated levels of nitrates in drinking water can lead to methemoglobinemia, commonly referred to as "blue baby syndrome." This health condition primarily affects infants and is caused by the conversion of hemoglobin in the blood to methemoglobin, which is unable to effectively transport oxygen. Nitrates can be converted into nitrites by bacteria in the stomach, especially in young children, resulting in reduced oxygen availability in the bloodstream. Symptoms of methemoglobinemia can include a bluish tint to the skin, especially around the lips and fingertips, as well as difficulty breathing.

On the other hand, fluorosis relates to excessive fluoride intake during tooth development, dehydration is a loss of body fluids, and diarrhea is a condition often caused by infections or dietary factors, neither of which are directly linked to nitrate contamination in drinking water. Understanding the implications of high nitrate levels is crucial for ensuring safe drinking water and protecting public health, especially for vulnerable populations such as infants.