A lot of people drink coffee out of disposable cups from cafes. These have a plastic lining that will shed plastic from exposure to a hot acidic solution like coffee.
The limitations of an observational study like this is we don't know what compounding factors there are, does the method of drinking coffee matter? are people who eat white rice more likely to chew on their pens?
Not trying to play defense for the industries producing these foods but they are all basic foodstuffs and I'm not going to make any dietary changes based on this yet.