|The river Elbe: processes affecting the behaviour of metals and organochlorines during estuarine mixing|
Duinker, J.C.; Hillebrand, M.T.J.; Nolting, R.F.; Wellershaus, S. (1982). The river Elbe: processes affecting the behaviour of metals and organochlorines during estuarine mixing. Neth. J. Sea Res. 15(2): 141-169
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
|Authors|| || Top |
- Duinker, J.C.
- Hillebrand, M.T.J.
- Nolting, R.F.
- Wellershaus, S.
Attempts were made to determine the relative importance of chemical or physico-chemical processes and sedimentation and resuspension processes on the behaviour of metals (Cd, Zn, Cu, Pb, Cr, Mn, Fe, Ca, Al, Si, Ti, Mg), organic C and N and organochlorine compounds (α - and γ-hexachlorocyclohexane) in the estuarine region of the river Elbe in summer 1976. The latter processes seemed to be relatively less important than in some other estuaries. This may result from a much less pronounced mud shoal in the Elbe estuary. Such a mud shoal may act as a continuous source for tidal resuspension of bottom sediment particles. Alternating sedimentation and erosion resulted in systematic variations in the composition of suspended matter in terms of the relative contributions of two fractions. One fraction consisting of permanently suspended small and low-density particles having higher contents (weight to weight) of Cd, Zn, Cu, Pb, Cr, Mg and organic C and N.The other fraction consisting of resuspending larger and denser (mud) particles having higher contents of Mn, Fe, Al, Si and Ti. In addition to Al silicates, organic matter and Fe and Mn oxides may be important sites for trace elements (like Cd and Zn) in both fractions, but particularly so in the permanently suspended fraction. Evidence was found for the removal of Cd, Zn, Cu, Mn and Fe from solution into suspended particles during the initial phases of estuarine mixing. Estuarine mud, acting as sing for particulate pollutants, may thus accumulate originally dissolved components. A wide range of PCB components with high and low degrees of chlorination was present in solution as well as in suspension. Water was the most important carrier for components with low (and seston for those with high) degree of chlorination. Concentrations of individual PCB components ranged from picograms to nanograms per litre. The only compounds present in the estuary and the Wadden Sea above the detection limit in 1-litre samples were α - and γ-HCH, in the order of ng.1-1