What are the most common sources of microplastics that are retained in the human body? (Excreted microplastics concern me less) I would expect it is mostly syn

What are the most common sources of microplastics that are retained in the human body? (Excreted microplastics concern me less) I would expect it is mostly synthetic fiber from clothing, followed by processed food, but seems like we probably don't have that data yet.