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dc.contributor.authorSinger, Michael Bliss
dc.contributor.authorAalto, Rolf
dc.contributor.authorJames, L. Allan
dc.contributor.authorKilham, Nina E.
dc.contributor.authorHigson, John Lee
dc.contributor.authorGhoshal, Subhajit
dc.date.accessioned2013-11-01T17:01:01Z
dc.date.available2013-11-01T17:01:01Z
dc.date.issued2013
dc.identifier.citationSinger , M B , Aalto , R , James , L A , Kilham , N E , Higson , J L & Ghoshal , S 2013 , ' Enduring legacy of a toxic fan via episodic redistribution of California gold mining debris ' , Proceedings of the National Academy of Sciences of the United States of America , vol. 110 , no. 46 , pp. 18436-18441 . https://doi.org/10.1073/pnas.1302295110en
dc.identifier.issn0027-8424
dc.identifier.otherPURE: 22977348
dc.identifier.otherPURE UUID: 36c645eb-f93b-47f6-9e3b-a98306707bb6
dc.identifier.otherScopus: 84887418616
dc.identifier.urihttps://hdl.handle.net/10023/4138
dc.descriptionThis work was supported by National Science Foundation Grants BCS-0521663 and EAR-1226741 (to M.B.S.), Grant BCS-0520933 (to L.A.J.), and Grant BCS-0521774 (to R.A.). M.B.S. also received support from The Carnegie Trust for Scottish Universities and The Royal Society of Edinburgh. J.L.H. was supported by a Natural Environment Research Council Fellowship (United Kingdom).en
dc.description.abstractThe interrelationships between hydrologically driven evolution of legacy landscapes downstream of major mining districts and the contamination of lowland ecosystems are poorly understood over centennial time scales. Here, we demonstrate within piedmont valleys of California’s Sierra Nevada, through new and historical data supported by modeling, that anthropogenic fans produced by 19th century gold mining comprise an episodically persistent source of sediment-adsorbed Hg to lowlands. Within the enormous, iconic Yuba Fan, we highlight (i) an apparent shift in the relative processes of fan evolution from gradual vertical channel entrenchment to punctuated lateral erosion of fan terraces, thus enabling entrainment of large volumes of Hg-laden sediment during individual floods, and (ii) systematic intrafan redistribution and downstream progradation of fan sediment into the Central Valley, triggered by terrace erosion during increasingly long, 10-y flood events. Each major flood apparently erodes stored sediment and delivers to sensitive lowlands the equivalent of ∼10–30% of the entire postmining Sierran Hg mass so far conveyed to the San Francisco Bay-Delta (SFBD). This process of protracted but episodic erosion of legacy sediment and associated Hg is likely to persist for >104 y. It creates, within an immense swath of river corridor well upstream of the SFBD, new contaminated floodplain surfaces primed for Hg methylation and augments/replenishes potential Hg sources to the SFBD. Anticipation, prediction, and management of toxic sediment delivery, and corresponding risks to lowland ecology and human society globally, depend on the morphodynamic stage of anthropogenic fan evolution, synergistically coupled to changing frequency of and duration extreme floods.
dc.language.isoeng
dc.relation.ispartofProceedings of the National Academy of Sciences of the United States of Americaen
dc.rightsCopyright 2013, the Authors. This is a paid Open Access article and made freely available online through the PNAS open access option.en
dc.subjectMercuryen
dc.subjectLowland contaminationen
dc.subjectFlood frequencyen
dc.subjectClimate changeen
dc.subjectMorphodynamicsen
dc.subjectGE Environmental Sciencesen
dc.subjectSDG 13 - Climate Actionen
dc.subject.lccGEen
dc.titleEnduring legacy of a toxic fan via episodic redistribution of California gold mining debrisen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. Earth and Environmental Sciencesen
dc.contributor.institutionUniversity of St Andrews. Scottish Oceans Instituteen
dc.identifier.doihttps://doi.org/10.1073/pnas.1302295110
dc.description.statusPeer revieweden
dc.identifier.urlhttp://www.pnas.org/lookup/suppl/doi:10.1073/pnas.1302295110/-/DCSupplementalen


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