To How Much Manganese Are Welders Exposed?
In "Manganese, Iron, and Total Particulate Exposures to Welders" the authors analyzed multiple sets of data in an attempt to characterize exposures generated by welding. They conclude that manganese exposures are likely often above the current TLV of 0.2 mg/cubic meter.
Significantly, they also report strong and consistent correlations between levels of manganese, iron and total particulate that, they suggest, would allow the extrapolation of manganese exposure where only data on say iron exposure is available. Expect to see this approach used to demonstrate high exposures where none were seen before.
