Release of trace contaminants during reoxidation of anoxic sediment slurries in oxic water

Polluted sediments are periodically subjected to resuspension processes resulting from natural events such as, for example, storm occurrences or extreme high waters as well as to anthropogenically induced activities such as dredging or shipping. The main part of the resuspended material is initially in an anoxic state and will be more or less quickly reoxidized in the oxic water column. The release of Cd, Cu, Zn, Pb together with the behaviour of the nutrients PO_4, SO_4, NO_3 and NH_4 during this reoxidation have been investigated in suspensions of anoxic sediment material in oxic river water under controlled pH conditions. Up to 5% of the particulate bound heavy metals were remobilized from the sediments. Different elements showed different behaviour which could be attributed to different microbial processes. The comparison of the release under different temperature conditions with poisoned suspensions illustrated the strong effect biological activity can have on the release. (orig.)Also published in: Arch. Hydrobiol. Spec. Issues Advanc. Limnol. (Feb 1996) v. 47. p. 295-305Available from TIB Hannover: RA 3251(96/E/16) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman