@article{10272/22162,
year = {2023},
url = {https://hdl.handle.net/10272/22162},
abstract = {This study evaluates for the first time the impact of a large wildfire on the hydrogeochemistry of a deeply AMDaffected
river at the beginning of the wet season. To accomplish this, a high-resolution water monitoring
campaign was performed within the basin coinciding with the first rainfalls after summer. Unlike similar events
recorded in AMD-affected areas, where dramatic increases in most dissolved element concentrations, and decreases
in pH values are observed as a result of evaporitic salts flushing and the transport of sulfide oxidation
products from mine sites, a slight increase in pH values (from 2.32 to 2.88) and decrease in element concentrations
(e.g.; Fe: 443 to 205 mg/L; Al: 1805 to 1059 mg/L; sulfate: 22.8 to 13.3 g/L) was observed with the first
rainfalls after the fire. The washout of wildfire-ash deposited in the riverbanks and the drainage area, constituted
by alkaline mineral phases, seems to have counterbalanced the usual behavior and patterns of the river
hydrogeochemistry during autumn. Geochemical results indicate that a preferential dissolution occurs during ash
washout (K > Ca > Na), with a quick release of K followed by an intense dissolution of Ca and Na. On the other
hand, in unburnt zones parameters and concentrations vary to a lesser extent than burnt areas, being the washout
of evaporitic salts the dominant process. With subsequent rainfalls ash plays a minor role on the river hydrochemistry.
Elemental ratios (Fe/SO4 and Ca/Mg) and geochemical tracers in both ash (K, Ca and Na) and AMD
(S) were used to prove the importance of ash washout as the dominant geochemical process during the study
period. Geochemical and mineralogical evidences point to intense schwertmannite precipitation as the main
driver of reduction in metal pollution. The results of this study shed light on the response of AMD-polluted rivers
to certain climate change effects, since climate models predict an increase in the number and intensity of
wildfires and torrential rain events, especially in Mediterranean climates.},
organization = {This research was supported by the AIHODIEL project (PYC20 RE 032 UHU) within the 2020 call for grants for the implementation of projects of collaborative interest in the field of innovation ecosystems co-financed by the FEDER program in Andalucía for the period 2014-2020. Jonatan Romero is financed by a FPU program of the Spanish Ministry of Education of Vocational Training (FPU20/04441). C.R Cánovas thanks the Spanish Ministry of Science and Innovation for
the Postdoctoral Fellowship granted under application reference RYC2019–027949-I. Funding for open access charge: Universidad de Huelva / CBUA. The authors gratefully appreciate the constructive comments and suggestions from the editor Mark van Loosdrecht and two anonymous reviewers.},
publisher = {Elsevier},
keywords = {Mining pollution},
keywords = {Seasonal variations},
keywords = {Natural attenuation},
keywords = {Ash},
keywords = {Evaporitic salts washout},
keywords = {Climate change},
title = {Wildfire effects on the hydrogeochemistry of a river severely polluted by acid mine drainage},
doi = {10.1016/j.watres.2023.119791},
author = {Romero Matos, Jonatan and Ruiz Cánovas, Carlos and Macías Suárez, Francisco and Pérez López, Rafael and León, Rafael and Millán Becerro, Ricardo and Nieto Liñán, José Miguel},
}