Effects of Microplastics on Humans

There are considerable gaps in knowledge of the effects of microplastics on humans, though it is becoming an increasingly important topic, especially since microplastics have been found in tap and bottled water around the world.  I assume that after such information, more focus will be put on research of the effects of microplastics on human health.  I would appreciate the documents you may have on the topic (proven facts or assumptions).