Why is there a great concern about the ‘microbeads’ that are released into environment?

The correct answer is: They are considered harmful to marine ecosystems.

Explanation:

Microbeads are manufactured solid plastic particles of less than 1 mm (0.04 inches) in size. They are most frequently made of polyethylene but can be of other petrochemical plastics such as polypropylene and polystyrene. They are used in personal care products like scrubs, soaps, and toothpaste as exfoliating agents.

When these products are washed down the drain, microbeads easily pass unfiltered through household sewage treatment systems because of their extremely small size. Consequently, they enter water bodies such as rivers, lakes, and oceans. In marine environments, aquatic animals and fish often mistake microbeads for food and ingest them. This causes physical harm, toxic chemical bioaccumulation, and severe disruption to marine ecosystems and the food chain.