As the frequency of wildfires increases, more research is needed on the release of toxic pollutants into watersheds, according to a new review study published in the journal Water Resources Research. Better understanding how urban wildfires affect water quality will help water quality managers to anticipate, respond to, and potentially mitigate wildfire impacts.

“Much less studied are the effects of fire burning not only forests and grasslands but also houses, vehicles, and other human-made material,” said study co-author Stephen LeDuc, a biologist at the U.S. Environmental Protection Agency’s Center for Public Health and Environmental Assessment. “There have only been a few studies of pollutants mobilized from these types of fires.”

Together with his colleagues, LeDuc examined trends in water after wildfires as documented in 184 scientific articles published since 1980. The analysis revealed that stream flow often increases for several years after a wildfire, as do sediments, water temperature, nutrients, as well as toxic metals and organic chemicals – which sometimes reach between ten to 100 times higher concentrations than before the fire.