What is the primary cause of blue baby syndrome?

The primary cause of blue baby syndrome, or methemoglobinemia, is related to elevated levels of nitrates in drinking water. Nitrates are commonly found in agricultural fertilizers and can leach into groundwater, especially in areas with heavy farming activities. When infants consume water or formula that contains high nitrate levels, their bodies may convert hemoglobin into methemoglobin, which cannot effectively carry oxygen. This results in a decrease of oxygen in the blood, leading to a bluish tint in the skin, hence the term "blue baby syndrome."

Understanding the impact of nitrates highlights the importance of monitoring water quality, especially in agricultural regions, to prevent associated health risks in vulnerable populations, such as infants. The other options, while they pose significant health risks, do not specifically lead to the physiological mechanism that causes blue baby syndrome.