Magnetite pollution nanoparticles in the human brain

It is a hazard but may we consider it as a risk?
A fascinating studies.
Magnetite pollution nanoparticles in the human brain are similar than those produced by gaz combustion especially diesel or brake friction.

 (PNAS)

vol. 113 no. 39

> Barbara A. Maher,  10797–10801, doi: 10.1073/pnas.1605941113