Toxicity of Wildland Fire Retardants to Rainbow Trout in Short Exposures

Long-term wildland fire retardants are one important tool used to control and suppress wildfires. During suppression activities, these retardants may enter water bodies; thus, there is a need to understand their potential effects on aquatic biota. We investigated the effect of three current-use wildland fire retardants to juvenile rainbow trout (Oncorhynchus mykiss) survival in short exposures more realistic to actual intrusion scenarios. Lethal effect concentrations decreased with time and varied among chemicals (LC95A-R > 259-Fx > MVP-Fx). The lowest effect concentrations observed were 2 to 10 times above the threshold used by federal agencies to assess potential impacts to aquatic organisms following a retardant intrusion. These data can be used by resource managers to balance wildfire control with potential environmental impacts of retardant use. Environ Toxicol Chem 2024;43:398-404. Published 2023. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.