Researchers have discovered significant quantities of potentially toxic magnetic nanoparticles in human brains, sparking fears they could lead to brain diseases.
The particles, made of a form of iron called magnetite, are produced during combustion and can reach high levels in polluted areas. A study published Sep. 5 in the journal Proceedings of the National Academy of Sciences suggests these pollutants can make their way into the brain when inhaled, either through the lungs or more likely directly through the olfactory bulb, where smell is processed.
In the paper, scientists examined the brains of people who lived in Mexico City and Manchester, England, and who were subject to high levels of particulate pollution during their lives. Some of the people also had Alzheimer’s disease or dementia, and researchers are concerned these particles may increase the risk for such brain diseases, says Barbara Maher, a scientist at the University of Lancaster, and the study’s first author.