Problem 9 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Which of the following conditions in drinking water causes methemoglobinemia? (a) \(>50 \mathrm{ppm}\) of lead (b) \(>50\) ppm of chloride (c) \(>50\) ppm of nitrate (d) \(>100 \mathrm{ppm}\) of sulphate

Step-by-Step Solution

Answer

The condition is caused by >50 ppm of nitrate in drinking water.

Step 1: Understanding Methemoglobinemia

Methemoglobinemia is a condition where there is an elevated level of methemoglobin in the blood, which reduces the ability of blood to release oxygen to tissues. This condition is often caused by drinking water contaminated with high levels of certain chemicals.

Step 2: Analyzing Each Option

Let's go through each option to determine which substance caused methemoglobinemia: - (a) Lead: High levels of lead can lead to poisoning but not typically methemoglobinemia. - (b) Chloride: Chloride in water does not cause methemoglobinemia. - (c) Nitrate: High nitrate levels in drinking water are known to cause methemoglobinemia, particularly in infants, due to conversion into nitrites which oxidize hemoglobin. - (d) Sulphate: Sulphate is not typically associated with causing methemoglobinemia.

Step 3: Conclusion

After evaluating all the options, we determine that high nitrate levels ( >50 ppm ) in drinking water are responsible for causing methemoglobinemia.

Key Concepts

Nitrate Contamination

Nitrate contamination in water sources is a growing concern for many communities. Nitrates are compounds commonly found in fertilizers, and they often infiltrate water systems through agricultural runoff. When nitrates exceed safe levels - for drinking water, this is typically above 50 ppm (parts per million) - they pose a risk to human health. It's important to monitor these levels carefully to ensure safety.

• Sources include agricultural runoff, septic systems, and industrial waste.
• Nitrates convert to nitrites in the digestive system, which can be harmful.
• Infants and pregnant women are particularly vulnerable to the effects of high nitrate levels.

Maintaining a close watch on nitrate levels in water supplies is crucial to prevent health complications like methemoglobinemia. Proper management and testing of water help control and reduce nitrate contamination.

Drinking Water Safety

Ensuring drinking water safety is critical for public health. Safe water is free from contaminants that can cause diseases, like methemoglobinemia. Multiple procedures exist to ensure that water remains at safe consumption levels.

• Regular testing of water sources to identify and measure contaminants.
• Treatment methods such as filtration and reverse osmosis to remove impurities.
• Community awareness programs to help residents understand risks and prevention methods.

Governments and agencies work collaboratively to set regulations and guidelines to assure that drinking water remains safe for all. Preventative measures and effective water treatment systems prevent health issues and support overall community well-being.

Blood Oxygenation Issues

Blood oxygenation issues arise when the blood cannot effectively carry enough oxygen to body tissues. Methemoglobinemia is one condition leading to such issues, caused by the conversion of normal hemoglobin into methemoglobin which can't bind oxygen effectively.

• This compromised oxygen transport results in symptoms like cyanosis (a bluish tinge to the skin) and fatigue.
• High nitrate concentrations are culprits, converting to nitrites, which preserve methemoglobin at unsafe levels.
• Infants are particularly susceptible due to their immature enzyme systems, often leading to more severe symptoms.

Recognizing and addressing blood oxygenation issues promptly can prevent serious health consequences. Medical treatments for elevated methemoglobin levels usually involve administration of methylene blue, which restores normal hemoglobin levels and oxygen transport.