Wildfire-driven changes in hydrology mobilize arsenic and metals from legacy mine waste
| Autor: | JoAnn M. Holloway, Jeffrey H. Writer, Deborah A. Martin, Sheila F. Murphy, R. Blaine McCleskey |
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| Rok vydání: | 2020 |
| Předmět: |
Hydrology
Environmental Engineering 010504 meteorology & atmospheric sciences chemistry.chemical_element STREAMS 010501 environmental sciences 01 natural sciences Pollution Deposition (geology) Hydrology (agriculture) chemistry Environmental Chemistry Environmental science Water quality Surface runoff Subsurface flow Waste Management and Disposal Surface water Arsenic 0105 earth and related environmental sciences |
| Zdroj: | The Science of the total environment. 743 |
| ISSN: | 1879-1026 |
| Popis: | Wildfires burning in watersheds that have been mined and since revegetated pose unique risks to downstream water supplies. A wildfire near Boulder, Colorado, that burned a forested watershed recovering from mining disturbance that occurred 80–160 years ago allowed us to 1) assess arsenic and metal contamination in streams draining the burned area for a five-year period after the wildfire and 2) determine the fire-affected hydrologic drivers that convey arsenic and metals to surface water. Most metal concentrations were low in the circumneutral waters draining the burned area. Water and sediment collected from streams downstream of the burned area had elevated arsenic concentrations during and after post-fire storms. Mining-related deposits were the main source of arsenic to streams. An increased proportion of overland flow relative to infiltration after the fire mobilized arsenic- and metal-rich surface deposits, along with wildfire ash and soil, into streams within and downstream of the burned area. The deposition of this material into stream channels resulted in the remobilization of arsenic for the five-year post-fire study period. It is also possible that enhanced subsurface flow after the fire increased contact of water with arsenic-bearing minerals exposed in underground mine workings. Other studies have reported that wildfire ash can be an important source of arsenic and metals to surface waters, but wildfire ash was not a major source of arsenic in this study. Predicted increases in frequency, size, and intensity of wildfires in the western U.S., a region with widely dispersed historical mines, suggest that the intersection of legacy mining and post-wildfire hydrologic response poses an increasing risk for water supplies. |
| Databáze: | OpenAIRE |
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