Manganese species migration in soil at the Sabine National Wildlife Refuge, Louisiana

A modified sequential extraction procedure was employed to speciate the che mical forms of Mn in sediment using flame atomic absorption spectrophotomet ry. Concentrations were determined in five different fractions for each sam ple (Mn in the exchangeable form, bound to carbonates, bound to Mn/Fe oxide s, bound to organic matter and in the residual form). The determinations we re made for sediments obtained from the Sabine National Wildlife Refuge whi le a marshland reclamation project was being conducted. Sediment samples we re taken from Ship Channel dredge spoils (thought to be contaminated). an o ld reclamation site. a new reclamation site and a reference site. The resul ts indicated that the Ship Channel sediments were not contaminated. but rev ealed an Mn "pumping" model, which proposes that additional Mn added to a s imilar site is-concentrated near the surface soil layers by environmental c onditions, which may be a cause of the observed slow recovery of vegetation at one of the more recently developed sites.