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TitleThe stability of metal profiles in freshwater and marine sediments
AuthorOutridge, P M; Wang, F
SourceEnvironmental contaminants: Using natural archives to track sources and long-term trends of pollution; by Blais, J M (ed.); Rosen, M R (ed.); Smol, J P (ed.); .
Alt SeriesEarth Sciences Sector, Contribution Series 20130196
PublisherSpringer
Documentbook
Lang.English
Mediapaper
Subjectsenvironmental geology; geochemistry; marine geology; metallic minerals; sedimentology; sedimentation; sediments; metals; bioturbation; oxidation; oxidation reactions; groundwater pollution; pollution; pollutants; heavy metals geochemistry; heavy metals contamination; diagenesis; mercury; lead; arsenic; cadmium; copper; molybdenum; nickel; uranium; zinc; sea water geochemistry; water geochemistry; water quality; rhenium
Illustrationsgeochemical plots; schematic diagrams; equations
Programenvironmental impacts and adaptation in the northern environment, Environmental Geoscience
AbstractStability of metal profiles, or the ability to reconstruct the original profiles following their diagenetic redistribution, is a key requirement for robust interpretations of metals in sediments. Diagenesis is a common problem in the study of metals in freshwater and marine sediments, but its effects are difficult to generalize because they are metal- and site-specific. There are two basic types of diagenesis; both may strongly influenced by biological activities in sediments: physical, which involves the mixing of surface sediments by bioturbation or wind and wave action, and which may affect all metals in upper sediment layers; and geochemical, which involves chemical reactions between certain metals in solid-phases and in porewater, and the transport in porewater of dissolved metals. A few metals of environmental or paleo-limnological interest, such as Hg and to a lesser extent Pb, are thought to be geochemically stable in most settings. Others such as As, Cd, Cu, Mo, Ni, Re, U and Zn are known to be relatively sensitive to oxic-anoxic (redox) changes down-core and over time. This literature review fulfills several aims: describe the patterns and mechanisms of the two main categories of diagenesis, physical and geochemical; describe three tests of metal profile stability; review environmental and geochemical factors that influence the occurrence and severity of diagenesis, some of which differ significantly between the two types of diagenesis; present case studies that illustrate working approaches for correcting diagenetically-altered profiles so that part or all of the original history of accumulation can be reconstructed; and finally, present practical recommendations concerning study site selection, and approaches to detecting diagenesis, which may assist in minimizing or at least identifying the severity of metal redistribution.
Summary(Plain Language Summary, not published)
Diagenesis is a common problem in the study of metals in freshwater and marine sediments, but its effects are difficult to generalize because they are metal- and site-specific. A few metals of environmental or paleo-limnological interest, such as Hg and to a lesser extent Pb, are thought to be geochemically stable in most settings. Others such as As, Cd, Cu, Mo, Ni, Re, U and Zn are known to be relatively sensitive to oxic-anoxic (redox) changes down-core and over time. This literature review fulfills several aims: describe the patterns and mechanisms of the two main categories of diagenesis; describe three tests of metal profile stability; review environmental and geochemical factors that influence the occurrence and severity of diagenesis; present case studies that illustrate working approaches for correcting diagenetically-altered profiles so that part or all of the original history of accumulation can be reconstructed; and finally, present practical recommendations concerning study site selection, and approaches to detecting diagenesis.
GEOSCAN ID292932