Power plants: The need for effective bio-monitoring of the contribution of bio(wood) fuelled stations to atmospheric contamination

Wood resources will increase their share of the world energy market in the next 20 years due to state subsidies and increased global pellet exportation. Although environmental impacts of wood combustion are worse than those of combustion of coal, a literature review revealed very few works investigating the effects of Biomass Power Plants (BPPs). Coal Power Plants made a significant contribution to atmospheric enrichment in Cr, Pb, Ni, Zn, As, Mn and V. Regarding Biomass Power Facilities (BPFs), waste-to-energy plant emissions were traced by Hg, Mn, Cu, As, V and Fe monitoring and the lichen biodiversity index. Works investigating wood-powered stations showed that emissions are consistent with the geochemical properties of substrates where forestall resources were grown (Al, Ti, V and Co enrichment), as well as the combustion of timber from both Short Rotation Forestries/Coppices and chemically treated demolition wood (Cu, Mn, Cr, As, Sb). Overall Cu, due to frequent detection within contaminants, may be considered a potential tracer of atmospheric emissions of BPFs. Two were the most important results of the review: a) important factors affecting the studies' outcomes were stack height of the facility, wind speed and direction, monitoring stations density and distance from the point sources, b) improvements in the accurate detection of contamination levels/extent of the affected area and the association between facilities and spatial trend of atmospheric impacts can be obtained by the use of an internal control group, an a posteriori null hypothesis and quantitative relationships between winds and toxic substances.