Wildfire-driven changes in hydrology mobilize arsenic and metals from legacy mine waste

• DOI: 10.1016/j.scitotenv.2020.140635
• Publication Date: 2020-07-02T15:49:39Z
• Authors: Sheila F. Murphy; R. Blaine McCleskey; Deborah A. Martin; JoAnn M. Holloway; Jeffrey H. Writer
• Keywords: 13. Climate action; 0207 environmental engineering; 02 engineering and technology; 15. Life on land; 6. Clean water

Wildfires burning in watersheds that have been mined and since revegetated pose unique risks to downstream water supplies. A wildfire near Boulder, Colorado, burned a forested watershed recovering from mining disturbance occurred 80–160 years ago allowed us 1) assess arsenic metal contamination streams draining the area for five-year period after 2) determine fire-affected hydrologic drivers convey metals surface water. Most concentrations were low circumneutral waters area. Water sediment collected of had elevated during post-fire storms. Mining-related deposits main source streams. An increased proportion overland flow relative infiltration fire mobilized arsenic- metal-rich deposits, along with ash soil, into within The deposition this material stream channels resulted remobilization study period. It is also possible enhanced subsurface contact arsenic-bearing minerals exposed underground mine workings. Other studies reported can be an important waters, but was not major study. Predicted increases frequency, size, intensity wildfires western U.S., region widely dispersed historical mines, suggest intersection legacy post-wildfire response poses increasing risk