There is some concern regarding the nano-particles 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 code given below.
a) 1 and 2 only
b) 3 only
c) 1 and 3 only
d) 1, 2 and 3

Ans-[D] 

Explanation- All statements are correct.

A nanoparticle (or nanopowder or nanocluster or nanocrystal) is a microscopic particle with at least one dimension less than 100 nm. Nanoparticle research is currently an area of intense scientific research, due to a wide variety of potential applications in biomedical, optical, and electronic fields.

Nanoparticles can easily contaminate the environment. They may be directly toxic to microbes, plants, and animals. Silver nanoparticles, for instance (though they are not toxic to humans), dissolve in water and release silver ions which are antibacterial. If silver nanoparticles are released into the environment, these types of concentrated silver ion releases could devastate local bacterial populations, with drastic consequences for the affected ecosystems. In this way, it can also enter into the food chain if some bacteria like this infects the food. There are other ways too but nanoparticles can enter the food chains.

Free radicals are an uncharged molecule typically highly reactive and short-lived, having an unpaired valency electron. Nanoparticles are capable of making free radicals. For example, at nanoscale these particles can easily enter inside the cells and cause biochemical changes via formation of free radicals. In human cells also they enter like this. Free radicals in biochemical reaction of humans have been linked with the Alzheimer’s and Parkinson’s diseases.