What are microplastics and why are they a concern in ecosystems?

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Microplastics are plastic particles smaller than 5 millimeters, coming from the breakdown of larger plastics or manufactured as tiny beads in products. They persist in the environment and break into even smaller pieces rather than dissolving away. Because of their tiny size, they are readily ingested by a wide range of organisms, leading to accumulation in tissues over time. Inside the body, microplastics can carry pollutants onto their surfaces and may release them, increasing exposure to toxins. This combination of persistence, uptake by organisms, and transfer of contaminants can disrupt growth, reproduction, and survival, and it can move through food webs, altering ecosystem dynamics. So the concern is not that microplastics are simply present, but that they persist, accumulate in organisms, and facilitate toxin transfer, threatening ecological health. Larger plastic debris, harmless microbeads, or natural fragments that dissolve quickly do not describe microplastics or their ecological impact accurately.