Accumulation of plastic is a [[1]] problem

Plastics are low-cost, robust, lightweight, corrosion-resistant, long-lasting materials with excellent thermal and electrical insulation. Nowadays, virgin plastic polymers are seldom utilised; instead, the polymer resins are often blended with other additives to increase their performance, such as inorganic fillers, plasticizers, retardants, etc.
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Both landfills and our natural ecosystem have grown significantly plastic-filled. When cows, dogs, or other animals ingest the plastic that has collected on the soil, it suffocates them to death and suffocates their throats. A broad variety of natural terrestrial, freshwater, and marine environments are also contaminated by discarded plastic, with plastic litter even present on some of the highest mountains.

The majority of polymers are buoyant in water (float on water), and since plastic trash like cartons and bottles frequently trap air, there is a significant buildup of plastic debris on the ocean's surface and the possibility of it washing ashore. These prevent oxygen from dissolving in the water, lowering the water's dissolved oxygen level. Fish and other marine creatures perish as a result of this. Plastics are bad for the environment. They need a lot of space, money, and energy to discharge since they don't quickly degrade and can't be utilised again in big numbers. The plastics are also collected by rag-pickers from a landfill location, where they frequently develop lung conditions due to the production of ethylene and methane fumes during decomposition. The health of people is harmed by these gases.
So, we saw that if plastic builds up in nature, it causes a lot of difficulties and is a big concern.

Hence, the correct answer is serious.