Micronized copper wood preservatives: An efficiency and potential health risk assessment for copper-based nanoparticles

• We compared copper particulate wood preservatives with conventional ones.
• We assessed the fungicidal activity of particulate copper wood preservatives.
• We reviewed the Cu-tolerance mechanisms of some wood-destroying fungi.
• Fungi colonizing wood treated with particulate copper may release Cu-loaded spores.

Copper (Cu) is an essential biocide for wood protection, but fails to protect wood against Cu-tolerant wood-destroying fungi. Recently Cu particles (size range: 1 nm–25 μm) were introduced to the wood preservation market. The new generation of preservatives with Cu-based nanoparticles (Cu-based NPs) is reputedly more efficient against wood-destroying fungi than conventional formulations. Therefore, it has the potential to become one of the largest end uses for wood products worldwide. However, during decomposition of treated wood Cu-based NPs and/or their derivate may accumulate in the mycelium of Cu-tolerant fungi and end up in their spores that are dispersed into the environment. Inhaled Cu-loaded spores can cause harm and could become a potential risk for human health. We collected evidence and discuss the implications of the release of Cu-based NPs by wood-destroying fungi and highlight the exposure pathways and subsequent magnitude of health impact.