Michael Kersten

Sediment Criteria Development

The role of sediments as carriers and potential sources of contaminants is reviewed. A program of sediment studies will normally consist of a series of objectives of increasing complexity, each drawing part of its information from the preceding data base. The study of dated sediment cores has proven particulary useful as it provides a historical record of the various influences on the aquatic system by indicating both the natural background levels and the man-induced accumulation of pollutants over an extended period of time. Since adsorption of pollutants onto particles is a primary factor in determining the transport, deposition, reactivity, and potential toxicity of these materials, analytical methods should be related to the chemistry of the particle’s surface and/or to the pollutant species highly enriched on the surface.

Mobility of Heavy Metals in Dredged Harbor Sediments

Solubility, mobility, and bioavailability of sediment-bound metals can be increased by four major factors: (1) Lowering of pH; (2) changing of redox conditions; (3) formation of organic complexes; and (4) increasing salinity. While the first two factors are particularly important for on-land deposition of dredged materials, the effect of salinity is particularly important for resuspended cadmium-rich sediments in estuaries. Chemical extraction studies, which were carried out under carefully controlled conditions on both fresh and freeze-dried samples, indicate that aeration of anoxic sediments (e.g., on-land disposal) may both increase and decrease the mobility of heavy metals. Transformation from sulfidic or carbonatic associations to oxidic phases will reduce mobility of manganese, wherease the respective changes from moderately reducible forms to carbonatic and easily reducible phases will enhance the reactivity of zinc during oxidation of dredged material.

Freisetzung von Metallen bei der Oxidation von Schlämmen : umweltchemische Aspekte der Baggergutdeponierung

Le depot de boues reduites dans les estuaires doit etre evite ainsi que la dispersion de sediments contamines dans des eaux peu profondes

Ansätze zur Beurteilung der "Sedimentqualität" in Gewässern

Developpement de criteres biologiques et chimiques pour caracteriser la qualite des sediments dans les milieux aquatiques