Workers’ dermal and total exposure to metals in biomass-fired power plants

The aim of this study was to measure ash removal and maintenance workers’ exposure to metals, and assess the suitability of different methods to evaluate metal exposure during these work tasks. Whole-body samples and hand-washing method were used in workers’ dermal exposure assessment, and biomonitoring methods of metals in total exposure assessment. The greatest levels of Al, Pb, Cd, Cu, S, and Zn on workers’ hands were measured in recycled fuel-fired power plants. The median concentrations of lead on workers’ whole-body samples were 4.5 ng/cm2, 17.0 ng/cm2, 11.3 ng/cm2, and 58.4 ng/cm2 in pellet-, peat-, wood- and recycled fuel-fired power plants, respectively. In recycled fuel-fired power plants, workers’ excretions of Al, Pb, and Mn exceeded the reference values of non-exposed population in 33%, 100%, and 50% of samples, respectively. The dermal exposure results clearly showed that power plant ash can significantly contaminate workers’ hands and bodies. The fact that the workers’ urinary excretions of metals exceeded the reference values proved intake of metals during these work tasks. Biomonitoring methods take into account exposures from different sources and, due to that, they are the most recommended approach for estimating the total metal exposure of workers. Hand-washing and whole body sampling were the most recommendable methods for assessing the protection efficiency of gloves and coveralls