P, As, Sb, Mo, and Other Elements in Sedimentary Fe/Mn Layers of Lake Baikal

Abstract

Distinct layers with accumulated iron and manganese oxyhydroxides are found in the recent sediments of Lake Baikal (Siberia). In the South and Central Basins, these concretions accumulate close to the sediment-water interface. In northern Lake Baikal and the area of Academician Ridge, however, massive Fe/Mn crusts are formed within several thousand years at redox fronts 10 to 15 cm below the sediment surface. In some places, precipitated iron and manganese oxyhydroxides are spatially separated. The patterns are a result of secondary iron and manganese oxide precipitation. This natural long-term experiment allows the analysis of competitive adsorption and coprecipitation of trace elements with iron and manganese oxides in sediments. Background concentrations in the sediment of oxoanions (P, As, Sb, Mo); of trace metals (Cr, V, Cu, Zn, Cd, Pb); and of Mg, Ca, Sr, La, Ce, Pr, Nd, and Sm were analyzed by inductively coupled plasma mass spectrometry. Despite the differences in catchment geology of the many tributaries, they are remarkably uniform in sediment cores from different basins of Lake Baikal. Enrichment factors of P and As within Fe crusts revealed concentrations up to 14 and 58 times higher than the background, respectively. No enrichment of P and As was found in the Mn layers. By contrast, Mo accumulated exclusively in the Mn layer with up to 35-fold enrichment. Sb was only slightly enriched in both the Fe and the Mn layers. Among the trace metals studied, only Cd was found at elevated concentrations with a preference for the Mn layer. Ca and Sr were correlated with both Fe and Mn accumulations. The study quantifies the well-known specific adsorption and coprecipitation of P and As at authigenic iron oxides and of Mo on manganese oxides. In addition, the enrichment of Cd at manganese oxides in contrast to the conservative behavior of Zn and Pb reveals highly selective accumulation processes.

Antimony leaching from contaminated soil under manganese- and iron-reducing conditions: column experiments

“…Although some studies have indicated the importance of Mn (hydr)oxides as sorbent phases for Sb in pure mineral systems, [24][25][26] in river deposits [49] and lake sediments, [28] their role in Sb mobility in soils has not been fully elucidated to date. This study demonstrates that Mn (hydr)oxides can play a key role in the mobility of Sb in natural soils.…”

“…[17] In an experiment on paddy soil, Mn (hydr)oxides were not considered important for Sb retention, [27] whereas in a study on lake sediments, Sb was found to sorb onto Mn oxides even in preference to Fe oxides. [28] As with Fe (hydr)oxides, antimonite exhibits a much higher sorption affinity to Mn (hydr)oxides than antimonate. [20,24] Once bound to Mn III/IV mineral surfaces, Sb III was found to be quickly oxidised and released as Sb V .…”

Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples

“…In recent sediments from Lake Baikal and the San Francisco Bay, iron and manganese oxides have been shown to be a significant sink for P, Mo, Pb, As and other heavy metals by adsorption and co-precipitation (Lion et al, 1982;Müller et al, 2002).…”

Attachment Behavior ofShewanella putrefaciensonto Magnetite under Aerobic and Anaerobic Conditions

“…Magnetite, therefore, may be an abundant attachment surface for DIRB in established iron reducing environments (Emerson 1976;Emerson and Widmer 1978;Karlin and Levi 1983;Karlin et al 1987;Maher and Taylor 1988;Pye et al 1990;Baedecker et al 1992). Though PO 3− 4 is often scarce in the subsurface, in many environments it occurs sorbed onto Fe oxides (Bostrom et al 1982;Shaffer 1986;Müller et al 2002), which may provide DIRB with this essential nutrient in close proximity to TEA. Alternatively, PO …”