Q. There is some concern regarding the nanoparticles of some chemical elements that are used by the industry in the manufacture of various products. Why?

  1. They can accumulate in the environment, and contaminate water and soil.
  2. They can enter the food chains.
  3. They can trigger the production of free radicals.

Select the correct answer using the codes given below:

  • 1 and 2 only
  • 3 only
  • 1 and 3 only
  • 1, 2 and 3

Answer: (d) 1, 2 and 3

Nanoparticles
  • A nanoparticle is defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. Nanoparticles are formed through the breaking down of larger particles or by controlled assembly processes.
  • Due to their ultrafine size, they can be suspended in the atmosphere for a long time and can travel larger distances. They possess very little mass but are many in number.
  • Nanoparticles are used in the manufacture of scratchproof eyeglasses, crack-resistant paints, anti-graffiti coatings for walls, transparent sunscreens, stain-repellent fabrics, self-cleaning windows, and ceramic coatings for solar cells.
  • Nanoparticles can also be used in stronger, lighter, cleaner, and “smarter” surfaces and systems.
  • The toxicity of nanoparticles depends on their chemical composition. The properties of particles may change in unpredictable ways at nanoparticle form.
  • Nanoparticle is responsible for the formation of dust clouds, Ozone depletion, environmental hydroxyl radical concentration, and stratospheric temperature changes.

Impact of Nanoparticles:

  • They can accumulate in the environment, and contaminate water and soil.
  • They can enter food chains.
  • They can trigger the production of free radicals.
  • Nanoparticles may cross cell membranes.
  • Nanoparticles can reach the blood and may reach other target sites such as the liver, heart, or blood cells and may cause damage to cells as they stay for a persistently long time.

Role of nanoparticles in air pollution:

  • Unlike their larger-sized soot particles (black carbon), nanoparticles can be activated as cloud droplets. High concentrations of these droplets increase the proportion of solar radiation reflected back to space, causing a cooling effect on climate.
  • Long exposures to high concentrations of nanoparticles cause lung problems and cardiovascular disease.
  • One of the key reasons for their negative health impact is their toxicity and large total surface area per unit mass. This increases their potential chemical reactivity and ability to be absorbed. They can pass deep into the respiratory system, reacting with the lung tissues and potentially entering the bloodstream.
  • Infant mortality, neonatal complications and birth defects are likely to increase with increasing concentrations of matter smaller than 10 µm.
  • As per a recent study, the number of black carbon particles that enter the mother is passed on proportionally to the baby.