Toxicity of fly ash effluent from the combustion of (chromated copper arsenate)-treated wood

Abstract

Wood is extensively used in Brazil and other countries to produce paper, building materials, and furniture, and a large amount of wood waste is produced. Chromated copper arsenate (CCA) is a preservative used in wood treatment because it can inhibit the action on biodeteriorating agents, therefore increasing the durability of the wood. As a result, environmental problems will arise due to the large amount of wood waste treated with CCA. The wasted CCA-treated wood is used as a fuel, resulting in the emission of toxic chemical compounds. Therefore, the aim of this work was to determine the toxicological effects of fly ash from the combustion of wood treated with CCA compared to the fly ash from untreated wood. Commercial samples of treated and untreated wood were subjected to controlled combustion. The particulate material, fly ash, was precipitated in water and in an acidic medium. The effluent from the HNO3 medium was submitted to analysis of metals (As, Cr, Cu) and polycyclic aromatic hydrocarbons (PAHs), and that collected in water was used for analysis of toxicity. The analysis of metals showed the presence of As and Cr in the effluent, main components of the chromated copper arsenate (CCA) salt. The toxicity analysis showed, in most cases, a significant increase in toxicity of the effluent from the combustion of the treated wood. However, there was some toxic effect on the effluent from the fly ashes of the untreated wood due to the presence of PAHs in them.

Keywords

• Chromated copper arsenate
• Biomass
• Treated wood
• Ecotoxicology