As fires continue to rage in California, leaving a trail of destruction and devastation in their wake, one has to question what impact this will have on local water resources. In a presentation given at a meeting hosted by the American Chemical Society earlier this year, researchers reported that wildfires burning in forested watershed have the potential to negatively impact Drinking water sources by releasing substances from soils which can make their way into local water sources, resulting in contamination.
Forested watersheds provide nearly two-thirds of America's drinking water, and globally supply drinking water to billions of people across the world. When Forested Watersheds are healthy, they absorb rainwater and melted snow, reduce storm runoff, remove pollutants, and play a key ecological role providing critical habitat for fish, birds and other wildlife. Forested watersheds are also provide recreational activities, such as fishing, swimming, kayaking, which in turn help support the local economy.
Water quality of these source waters can change significantly after a wildfire has ripped through a forested watershed, which can affect water treatment processes. Changes to the quality of source water include increased inflow of sediments, Dissolved Organic Carbon and nutrients, which may reduce the capacity of water treatment utilities to be able to deliver drinking water that meets safety standards set by the US Environmental Protection Agency (EPA). In order for water utilities to be adequately prepared for wildfire events, they need to understand what these impacts are, and how best to deal with them.
For the past seven years Fernando Rosario-Ortiz together with a team of fellow researchers from the University of Colorado, Boulder have been analyzing the impact that wildfires have on soil, and how soil is transformed by wildfires. The researchers simulated wildfire events of various magnitudes in a laboratory study, where they heated soil samples to different temperatures before analyzing the results.
"Up to a point, the warmer the soil gets, the more carbon- and nitrogen-containing compounds are released from soils," Fernando Rosario-Ortiz explains. "These compounds, which are generally characterized as dissolved organic carbon, can react with chemicals used to purify water and be transformed into disinfection byproducts, which you don't want in drinking water." Disinfection byproducts are considered a drinking water contaminant, and as such their levels are regulated by the EPA. "But we were surprised to find that as a wildfire increases in severity, the amount of dissolved organic carbon released by the soil decreases, and instead you could end up with more sediments in the source waters," says Rosario-Ortiz.
Rosario-Ortiz and his team are now focusing on how wildfires change how organic compounds are released from soils into water.
"We found that there is an enhanced release of compounds with a lower average molecular weight, containing both more oxygen and nitrogen functionalities, compared with typical conditions," Rosario-Ortiz reports, adding that the results from this study will help us to gain a clearer understanding of the overall effects that wildfires have on water quality and ultimately on the production of safe drinking water.
As the number of wildfires, and their severity, continues to increase due to factors such as climate change, extended periods of extreme droughts and an associated increase in fuel loads, this research is likely to provide important insights for drinking water utilities reviewing water treatment options following a severe wildfire event.
If your water is originating from a region impacted by forest fires, we would recommend a berkey water filter, which can remove dangerous contaminants from your drinking water.
