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New procedure for determining reactive Fe(III) and Fe(II) minerals in sediments
Author(s) -
Wallmann Klaus,
Hennies Kristof,
König Iris,
Petersen Wilhelm,
Knauth Hans-Diethard
Publication year - 1993
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1993.38.8.1803
Subject(s) - chemistry , ferrous , anoxic waters , extraction (chemistry) , sulfide , siderite , sediment , ferrihydrite , aqueous solution , zinc , ferric , chlorite , environmental chemistry , nuclear chemistry , inorganic chemistry , mineralogy , chromatography , geology , pyrite , adsorption , paleontology , quartz , organic chemistry
Sediments from the River Elbe estuary and incubated sediments were extracted with 1 N HCl for 24 h at room temperature. The extracted ferric and ferrous iron was determined with DC and AC polarography. Acid‐volatile sulfide was determined from H 2 S trapped in aqueous zinc acetate solution. Analysis of sediment samples and extraction residues with Mössbauer spectroscopy demonstrated that the Fe oxidation state was conserved during extraction and polarographic determination, siderite and vivianite were completely dissolved, and Fe(II) in chlorite was partially extracted with HCl. Incubation experiments showed that extractable Fe was almost completely oxidized to Fe(III) at the oxic sediment surface and reduced to Fe(II) in deeper anoxic layers within a few weeks. Reactive Fe(III), i.e. that fraction of Fe which was reducible on the time scale of the incubation experiment, was completely extracted with HCl.