They bioaccumulate because the “forever” part means they don’t break down. The reason they’ve been banned in food wrappers is that they accumulate to levels that become toxic. We should avoid them every way we can.
you don't absorb quartz through your skin and is inert if it gets into your stomach. small particles won't hurt your guts and will get pooped out; ingesting dirt is something that is not uncommon with animals, including people.