Where the metals come from
Depleted uranium, lead, arsenic, and others show up through combat, contaminated water and soil, industrial work, and old infrastructure. The military environment is full of them.
The body can't always excrete what it takes in, so some gets tucked away in tissue and bone — a quiet, long-term load.
Takeaway
Metals the body can't excrete get stored in tissue and bone as a long-term burden.