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 code given below.

1. They can accumulate in the environment and contaminate water and soil — Correct. Engineered nanoparticles can persist, disperse in soil/water, and cause environmental contamination due to their very small size and high reactivity.

2. They can enter the food chains — Correct. Nanoparticles can be taken up by microbes, plants, and aquatic organisms, leading to bioaccumulation and trophic transfer.

3. They can trigger the production of free radicals — Correct. Many nanoparticles induce oxidative stress by generating reactive oxygen species (free radicals), which is a major toxicological concern.

Therefore, all three statements are correct.