Microplstics are pollutants and are of the greatest concern to environmentalists.
Know and learn the major sources.
Washing Microplastics down the drain does not remove them even by using wastewater treatment, processes, or filtration systems.
Eventually this creates  problems and a kind of finely grained plastic particles in the environment & spreads to the ocean.
More Research is a must and hopefully this is and will happen. To be Continued.