The correct option is (d).
Explanation
Nanoparticles are particles with at least one dimension sized between 1 and 100 nanometers. Their extremely small size results in a high surface-area-to-volume ratio, which significantly alters their physicochemical properties compared to bulk materials. While these properties are useful in manufacturing, they also introduce specific environmental and toxicological risks.
Statement-wise Analysis:
- Statement 1 is Correct: Nanoparticles used in cosmetics, sunscreens, paints, and industrial coatings can be released into the environment during manufacture, use, or disposal. Due to their stability and small size, they can persist in the environment, bypass conventional filtration systems, and accumulate in water bodies and soil matrices.
- Statement 2 is Correct: Because of their minute dimensions, nanoparticles can easily penetrate biological barriers and cell membranes. They can be ingested by microorganisms and small aquatic animals, thereby entering the food chain. Once in the food chain, they have the potential for bioaccumulation and biomagnification in higher organisms.
- Statement 3 is Correct: The high surface reactivity of nanoparticles often leads to the generation of Reactive Oxygen Species (ROS) when they interact with biological systems. This triggers the production of free radicals, causing oxidative stress that can damage cellular structures, proteins, and DNA.
Key Takeaway:
The environmental and health concerns regarding nanoparticles arise primarily from their persistence in ecosystems, ability to bioaccumulate in food chains, and potential to cause cytotoxicity through the generation of free radicals.