|Biogeochemical behaviour of Cd, Cu, Pb and Zn in the Scheldt estuary during the period 1981-1983|
Baeyens, W.F.J.; Elskens, M.; Gillain, G.; Goeyens, L. (1998). Biogeochemical behaviour of Cd, Cu, Pb and Zn in the Scheldt estuary during the period 1981-1983, in: Baeyens, W.F.J. (Ed.) Trace metals in the Westerschelde Estuary: a case-study of a polluted, partially anoxic estuary. Hydrobiologia, 366(1): pp. 15-44
In: Baeyens, W.F.J. (Ed.) (1998). Trace metals in the Westerschelde Estuary: a case-study of a polluted, partially anoxic estuary. Hydrobiologia, 366(1). Developments in Hydrobiology, 128. ISBN 0-7923-5158-4. 167 pp., more
In: Hydrobiologia. Springer: The Hague. ISSN 0018-8158, more
|Also published as |
- Baeyens, W.F.J.; Elskens, M.; Gillain, G.; Goeyens, L. (1998). Biogeochemical behaviour of Cd, Cu, Pb and Zn in the Scheldt estuary during the period 1981-1983. Hydrobiologia 366: 15-44, more
|Authors|| || Top |
- Baeyens, W.F.J., more
- Elskens, M., more
- Gillain, G.
- Goeyens, L., more
Cu, Zn, Cd and Pb have been analysed in suspended matter and water samples from the Scheldt estuary, collected during five cruises between May 1982 and May 1983. In order to evaluate the overall metal behaviour in the estuary, continuous longitudinal profiles of the total, the particulate and the dissolved metal concentrations are discussed in relation to various specific physico-chemical parameters. By means of correlation and multi-regression techniques, several estuarine processes could be identified which dominate and/or control the behaviour of the individual trace metals in three distinct areas of the Scheldt estuary. The behaviour of the four selected metals was found to show some common features, but is besides this also characterised by many individual and specific properties. The total metal concentrations seem to co-vary well with the turbidity in the maximum turbidity zone between salinities 2 and 10 psu. In the downstream area a dilution profile is observed for the total metal concentrations of Cu and Cd as well as for the dissolved concentrations of all metals. Dissolved metal production rates are high for Cu and Cd, but much lower for Zn and Pb, confirming the different longitudinal dissolved metal profiles. For Cu and Cd these dissolved metal profiles are characterised by a broad mobilisation area, covering the whole middle estuary. Pb on the other hand, shows a more confined mobilisation area, and for Zn no such area was found. During winter the dissolved metal production rates seem to be controlled, predominantly, by desorption processes. During summer dissolved metal production is correlated mainly to the dissolved oxygen content, suggesting the domination of redox processes solely or in combination with desorption processes. In some cases, co-existent with nearly zero oxygen concentrations, removal of dissolved metals was observed, possibly reflecting precipitation reactions. Longitudinal particulate metal profiles all show a negative deviation versus the dilution profile. Cu and Cd provide the higher deviations, characterised by a narrow enrichment zone preceding a broad mobilisation area. Finally, all particulate metal profiles appeared to correlate well with POC, when expressed in volumetric units.