Nanoparticulate Wood Treatments Contribute to the Aquatic Toxicity of Simulated Urban Wildfire Ashes

Wildland-urban
interface fires often burn near important water
resources. The hazard of contaminant emissions from these fires to
aquatic biological systems remains incompletely described. To define
this hazard further, this study uses a laboratory simulation approach
to produce consistent synthetic wildland and urban mixture ashes.
These ashes are characterized through ecotoxicological assays, inductively
coupled plasma mass spectrometry (ICP-MS), and scanning electron microscopy-energy-dispersive
X-ray spectroscopy (SEM-EDS). Within the ecotoxicology screen, produced
urban ash leachates induce a greater toxic response to the microalgae Raphidocelis subcapitata, while the crustacean Daphnia
magna exhibited greater immobilization from synthetic wildland
ash. No substantial toxicity was observed in either the activated
sludge inhibition test or the seedling germination test, suggesting
that ecotoxicological effects from wildfire runoff may be highly species
specific. When characterizing the ashes, ICP-MS and SEM-EDS reveal
that nanoparticulate copper from pressure-treated wood likely contribute
to growth inhibition in Raphidocelis subcapitata.
Linking a potential specific toxic component may inform future ash
management and household material selection.