Methemoglobinemia disease is caused due to toxic concentration of
Show Hint
Remember the diagnostic terms:
- Nitrate contamination \(\rightarrow\) Blue Baby Syndrome \(\rightarrow\) Methemoglobinemia.
- This condition occurs when nitrite oxidizes the iron in hemoglobin from \( \text{Fe}^{2+} \) to \( \text{Fe}^{3+} \).
Step 1: Understanding the Concept:
Methemoglobinemia, commonly known as "blue baby syndrome," is a medical condition characterized by an abnormal increase in the level of methemoglobin in the blood.
Methemoglobin is a form of hemoglobin that cannot bind or deliver oxygen to body tissues, leading to tissue hypoxia. Step 2: Detailed Explanation:
Let us analyze the biochemical pathway that causes this disease: Nitrate Contamination: Runoff of nitrogenous fertilizers from agricultural fields can contaminate groundwater, leading to high concentrations of nitrate (\( \text{NO}_3^- \)) in drinking water. Reduction to Nitrite: When infants consume water or formula made with high-nitrate water, the low-acid environment in their immature digestive systems allows bacteria to rapidly reduce the nitrate to nitrite (\( \text{NO}_2^- \)):
\[ \text{NO}_3^- \xrightarrow{\text{Bacterial Reduction}} \text{NO}_2^- \] Hemoglobin Oxidation: The nitrite ions enter the bloodstream and react with the iron in hemoglobin, oxidizing divalent ferrous iron (\( \text{Fe}^{2+} \)) to trivalent ferric iron (\( \text{Fe}^{3+} \)). Methemoglobin Formation: This reaction converts normal hemoglobin into methemoglobin, which cannot transport oxygen.
This leads to oxygen deprivation in body tissues, causing the skin of infants to take on a bluish color (cyanosis).
The World Health Organization (WHO) has established a safe limit of \( 50 \text{ mg/L} \) for nitrate (or \( 3 \text{ mg/L} \) as nitrate-nitrogen) in drinking water to prevent this disease.
Sulphate, phosphate, and silicate do not cause this condition. Step 3: Final Answer:
Methemoglobinemia is caused by a toxic concentration of Nitrate.
