Microplastics are the miniscule plastic fragments (smaller than 0.04 inch) that fall off of decomposing plastic bottles and bags, and are intentionally manufactured into some toothpastes and lotions. Scientists have found microplastics nearly everywhere, particularly in lakes, rivers, and aquatic animals... U.S. Geological Survey and State University of New York Fredonia scientists sampled rivers flowing into the Great Lakes3 to find out which kinds of microplastics are most commonly found in rivers, and which rivers contain the most microplastics particles. These scientists found that rivers carry many different kinds of microplastics, and were surprised to learn that plastic microbeads make up only a small fraction of all microplastics.