Acid mine drainage (AMD) formed from pyrite weathering contributes to the degradation of surface water quality. Solar irradiation has been shown to be an important factor in the biogeochemical cycling of iron in AMD impacted waters but the impact of sunlit AMD waters on dissolved organic matter (DOM) fate is unknown. We observed photochemical mineralization of DOM with a half-life of 1-3 hours in a solar simulator resembling summer sunlight at 40° N in an AMD impacted water body from southeast Ohio (Essington Lake). By using selective probes and quantum yield calculations, we identified the importance of reactive species including hydroxyl and sulfate radicals on DOM degradation. The transformation of DOM composition was measured using size exclusion chromatography, mass spectrometry and nuclear magnetic resonance spectroscopy. The quantitative and qualitative change in DOM possibly constitutes an important component in regional carbon cycling and may influence downstream aquatic ecosystems in AMD affected watersheds.

Photomineralization of dissolved organic matter in acid mine drainage-impacted waters

253rd National Meeting (2017)

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