Active biological monitoring of the sediment : pilot study for use of a depositfeeder (Echino cardium cordatum) as a biomonitorspecies in a discharge area of TiO2 acid waste in the North Sea

In order to study the effects of titaandioxide acid waste in the North Sea a pilot study is performed to select a suitable depositfeeding species for an Active Biological Monitoring program, and to develop an 'in situ' device in which the organisms can survive and can be recaptured. From field sampling, survival tests 'in situ' and in the laboratory, ashfree dryweights, and heavy metal analyses the seaurchin Echinocardium cordatum turned out to be a suitable species. The device for monitoring 'in situ' appeared to be suitable in the Oosterschelde.