Abstract

In the WELDOX study a statistical model of the exposure to respirable manganese (Mn) in welders, based on the applied welding technique, the material and its manganese content, the room conditions and the ventilation was estimated. Using this model, prediction and prediction intervals (PI) of exposure were calculated and made available in an easy to use web tool for industrial hygienists in order to estimate the airborne concentration.

Between 2007 and 2009 personal sampling of respirable Mn was carried out in 241 welders during shift and information about the working conditions was gathered. The determinants of exposure concentrations were estimated with a multiple regression model that explained 72% of the variance. Prediction and 50%-, 80%- and 95%-PIs of Mn exposure were calculated and the results were graphically visualised. The predictions are valid for work places that are similar to the work places in the WELDOX study. A web tool was programmed and made available on a website.

The user selects the applied welding technique, type of material and Mn content, room condition and the efficiency of the ventilation system. Then he receives the prognosed respirable Mn concentration with PIs. For example a welder applying tungsten inert gas welding with stainless steel with a Mn content of the material below 1.7% under normal room conditions without an efficient ventilation system has a prognosed concentration of 5.8 µg/m³ with 95%-PI 0.6 – 53 µg/m³.

The presented web tool allows a fast prognosis of the respirable Mn exposure. It allows a quantitative prediction of the change of exposure concentrations when workplace characteristics are changed. Mn concentrations compiled in exposure databases may be helpful to validate the estimates.