Welders breathe, amass manganese in front regions of the brain, too.
Suman, S, MR Flynn, G Du, AI Troster, H An and X Huang. 2011. Manganese accumulation in the olfactory bulbs and other brain regions of “asymptomatic” welders. Toxicological Sciences http://dx.doi.org/10.1093/toxsci/kfr033.
Manganese breathed in from long-term, work-related activities can settle in more than one part of the brain, finds a small study of middle-aged men. The men experienced fine motor skills problems following the extensive, low-level exposures, the researchers report in the journal Toxicological Sciences.
The brain scans detected significant deposits of the mineral in many different brain regions, including the olfactory bulb. This part of the brain is important to the sense of smell, and may be an entry point for inhaled manganese to other regions of the brain.
Welders are exposed to many hazardous toxicants, including manganese. While manganese is a needed mineral in small amounts, it can have toxic effects. Exposure to high levels of manganese can lead to disorders of normal movement, memory and mood problems. The health effects of long-term exposure to lower levels of manganese are not known.
Previous brain scan research has detected manganese deposits, but they focused solely on the globus pallidus – a region of the brain involved with motor control and movement. Manganese can accumulate in this region of the brain and result in movement problems and tremors, a disorder known as “manganism.”
In the present study, researchers measured manganese deposits with magnetic resonance imaging (MRI) in several different brain regions in seven middle-aged men. They tested their fine motor skills, cognitive ability and sense of smell. All had been welders for an average of 24 years, had self-reported low manganese exposure and did not show any obvious motor or cognitive deficits. Seven middle-age men who did not weld were also tested for comparison on all measures, including MRI.
Brain imaging results measured significant manganese deposits in many brain regions, including the olfactory bulb and globus pallidus.
A deficit in fine motor skills in the non-writing hand was found. Fine motor skills were also affected in the writing hand, but these deficits were not statistically significant. Performance of the fine motor skills task was correlated with manganese deposits in some brain regions for both non-writing and writing hands.
No differences were measured on cognitive abilities or sense of smell.
The results are limited by the very small number of people studied. Further, although manganese is a major part of welding fumes, other metals that are known to affect health are also in these fumes, including iron and copper.
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