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UPSC Prelims 2021 · Environment · Pollution Files
Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following? Select the correct answer using the code given below
- Brakes of motor vehicles
- Engines of motor vehicles
- Microwave stoves within homes
- Power plants
- Telephone lines
- (a) 1, 2, 3 and 5 only
- (b) 1, 2 and 4 only
- (c) 3, 4 and 5 only
- (d) 1, 2, 3, 4 and 5
Show the answer and explanation
Answer: (d) 1, 2, 3, 4 and 5
The 2016 study (brain tissue from Mexico City) linked magnetite to traffic, combustion, and indoor sources including microwaves and telephone lines.
Statement by statement
1. ✓ YES Brake wear gives off iron-rich particles.
2. ✓ YES Engine combustion releases magnetite nanoparticles.
3. ✓ YES Microwave ovens are listed as an indoor source.
4. ✓ YES Power plants burning fuel release them.
5. ✓ YES Telephone lines (electrical equipment) are listed too.
The idea
Magnetite is an oxide of iron (Fe₃O₄) and is magnetic. Tiny particles of it form wherever iron-bearing material is heated strongly or rubbed hard: in engines, in brakes, in furnaces. Being extremely small, they can be breathed in and are thought to reach the brain through the nerve of smell.
High heat or friction on iron-bearing material → Magnetite nanoparticles form → Breathed in through the nose → Travel along the olfactory nerve → Found in brain tissue
The trap
Telephone lines and microwaves sound odd, but the source study listed them.
Also know
The link comes from a 2016 study of human brain tissue which found rounded magnetite particles of the kind made by high heat, unlike the angular ones the body makes naturally. Magnetite is also the main iron ore after haematite.
🔒 Magnetite (Fe₃O₄) nanoparticles in brains linked to Alzheimer’s (2016 study) — from traffic and combustion.