|Muehe, EM; Adaktylou, IJ; Obst, M; Zeitvogel, F; Behrens, S; Planer-Friedrich, B; Kraemer, U; Kappler, A: Organic carbon and reducing conditions lead to cadmium immobilization by secondary Fe mineral formation in a pH-neutral soil, Environmental Science and Technology(47), 13430−13439 (2013), doi:10.1021/es403438n|
Cadmium (Cd) is of environmental relevance as it enters soils via Cd-containing phosphate fertilizers and endangers human health when taken up by crops. Cd is known to associate with Fe(III) (oxyhydr)oxides in pH-neutral to slightly acidic soils, though it is not well understood, how the interrelation of Fe and Cd changes under Fe(III)-reducing conditions. Therefore, we investigated how the mobility of Cd changes when a Cd-bearing soil is faced with organic carbon input and reducing conditions. Using fatty acid profiles and quantitative PCR, we found that both fermenting and Fe(III)-reducing bacteria were stimulated by organic carbon-rich conditions, leading to significant Fe(III) reduction. The reduction of Fe(III) minerals was accompanied by increasing soil pH, increasing dissolved inorganic carbon and decreasing Cd mobility. SEM-EDX mapping of soil particles showed that a minor fraction of Cd was transferred to Ca- and S-bearing minerals, probably carbonates and sulfides. Most of the Cd, however, correlated with a secondary iron mineral phase that was formed during microbial Fe(III) mineral reduction and contained mostly Fe, suggesting an iron oxide mineral such as magnetite (Fe3O4). Our data thus provide evidence that secondary Fe(II) and Fe(II)/Fe(III) mixed minerals could be a sink for Cd in soils under reducing conditions, thus decreasing the mobility of Cd in the soil.
Physical constraints and biological controls of plant-environment interactions
Entfällt: 3x3=9: Wildkräuter für die Gründonnerstagssuppe
Entfällt: Mit tausend Schritten durch die Erdgeschichte: Gesteine im ÖBG
Entfällt: Der ÖBG zum Kennenlernen: Allgemeine Gartenführung
Von Sängern und Spöttern: Vogelstimmen im ÖBG (zusammen mit dem LBV)
Why Science Communication?
Stoichiometric controls of C and N cycling
Flying halfway across the globe to dig in the dirt – a research stay in Bloomington, USA
EGU – interesting research and free coffee