Microplastics are very tiny pieces of plastic that can be anywhere. They are the result of the breakdown of common plastic items such as plastic cutlery, food containers, bottles etc.
The impact of microplastics in our ecosystem and bodies is not yet well understood but is being studied. But ask yourself; do I want little bits of plastic in my blood? In my brain?
Using less plastic is a good first start that anyone can try to lessen the impact of plastic in general on the environment and ecosystem.
Microplastics that already exist in the 'wild' will mostly breakdown, but that could take hundreds, or more likely thousands of years. Ways to filter, gather and eliminate these tiny pollutants are currently being studied, but there's no single, perfect method. More studies and diligence will be required.