EVOLUTION OF TRACE-METAL CONCENTRATIONS IN THE SCHELDT ESTUARY (1978-1995) - A COMPARISON WITH ESTUARINE AND OCEAN LEVELS

Dissolved and particulate metal concentrations assessed in the Scheldt estuary in the period 1978-1995, yield a clear indication that the le vels of all metals decreased significantly. A comparison with other es tuaries classifies the Scheldt as being moderately polluted for all me tals in the dissolved phase, but as being fairly high polluted in the particulate phase, especially for Cd. However, even the dissolved meta l concentration fractions in the Scheldt are still between 10 and 50 t imes enriched compared to total metal concentrations in unpolluted sea s and oceans.