Degenerative Brain Disease and Dementia

"Our results indicate that magnetite nanoparticles in the atmosphere can enter the human brain where they might pose a risk to human health, including conditions such as Alzheimer's."
"The particles we found are strikingly similar to magnetite nanospheres that are abundant in the airborne pollution found in urban settings, especially next to busy roads and which are formed by combustion or frictional heating from vehicle engines or brakes."
"The paradigm until now has been that magnetite just forms naturally in the brain. Given how prolific magnetite particles are in the atmosphere, I wondered if they had gained entry into the human brain."
"They [the magnetite spheres] showed all the properties suggesting they formed in high temperatures. [The nanospheres are] combustion byproducts, like what’s found in power station pollution."
Physicist Barbara Maher, co-director, Centre for Environmental Magnetism and Paleomagnetism, Lancaster University

"This finding opens up a whole new avenue for research into a possible environmental risk factor for a range of brain diseases."
David Alsop, Alzheimer's researcher, Lancaster University

Power plants, like this one in Tyumen, Russia, let off air pollution that contains many nanoparticles, including magnetite. A new study finds this magnetite can make its way into human brains.

Sergei Butorin/iStockphoto

"Once you start getting larger volumes of [environmental] magnetite, the chemical reactivity goes way up."
"That nanoparticles of industrially generated magnetite are able to make their way into the brain tissues is disturbing."
Vassil Kirschvink, scientist who first detected biologically derived magnetite in the brain

Linked to the production of free radicals associated with Alzheimer's disease, magnetite is a toxic metal previously found in the brains of people who died of Alzheimer's, but considered to be a natural occurrence in the human body. But those tiny mineral balls identified by the scientists at Lancaster, Oxford and Manchester universities were identified as having a fused surface, the explanation for which was that they had been formed under conditions of extreme heat, such as would occur in a car engine.

Barbara Maher

These magnetite nanospheres, found in pollution from the United Kingdom's Didcot power station, match the magnetite researchers found in human brain samples. 

Diesel engines in particular are known to produce the form of iron oxide known as magnetite, emitting up to 22 times more particulate matter than gas-operated engines such as ordinary vehicles. Braking systems on vehicles and trains are also known to produce microscopic particles of magnetite, just as open fires and poorly fitted household stoves can, as well. The findings of this corps of researchers were published in the journal Proceedings of the National Academy of Sciences; findings which have opened an entirely new avenue of concern and research into Alzheimer's causes.

Although the researchers did find biologically derived magnetite particles, they were dwarfed in numbers by those that demonstrated by their fused state that they had an atmospheric presence in the particulate matter released by engines and power plants. At 150 nanometers or less in diameter, the magnetite nanoparticles at150 nanometers are sized to enable their intake through the human nose and from there, gain entry to the human brain.

 Air quality studies previously undertaken in the United Kingdom and Mexico City found urban areas, particularly along highways and roadsides have a plenitude of airborne magnetite, so that ordinary exposure on a city street renders ample opportunity for the toxic nanoparticles to be sniffed, ending up in the brain where their malevolent effect can lead to degeneration of the brain. The exposure threshold before the situation becomes dangerously threatening is as yet unknown, requiring further study.

It is sufficiently biologically disturbing that Dr. Maher feels the matter must be reviewed as an emergency given its prevalence in road traffic, the pollution that results from it, and the growing incidence of Alzheimer's: "It’s an unfortunately plausible risk factor, and it’s worth taking precautions. Policymakers have tried to account for this in their environmental regulations, but maybe those need to be revised", she advised

Other research concluded last week that scientists have discovered a drug that holds promise in halting the progress of Alzheimer's through clearing of the sticky plaques from the brain whose interference prevents brain cells from communicating. No one, however, yet understands what it is that causes the plaques to form, to begin with. An American study in 2014 demonstrated that people living in highly polluted environments were 50 percent likelier to suffer cognitive decline.

The recognition that environmentally-sourced metallic particles could infiltrate the brain was never even imagined.

The paper’s authors are Barbara Maher, David Allsop, Vassil Karloukovski and Penny Foulds from Lancaster University; Imad Ahmed from the University of Oxford; Donald MacLaren from the University of Glasgow; David Mann from the University of Manchester; Ricardo Torres-Jardon from the Universidad Nacional Autonoma de Mexico; and Lilian Calderon-Garciduenas from The University of Montana.