Estuarine sediment remediation: Effects on benthic biodiversity

Estuaries have been used historically for the disposal of a range of effluents, and this has led to wide-scale sediment and water column contamination. More recently, a number of national and international programmes have been implemented to improve estuarine water and sediment quality. In order to predict the ecological consequences of improved environmental quality, there is a need to understand the processes underlying the response of the biota. This paper reviews evidence from monitoring programmes and field experiments in the Tyne estuary (NE England) and the results of microcosm studies to assess the extent to which environmental remediation programmes have led to improvements in benthic communities. It was found that the changes in the Tyne have been largely the result of lowered sediment organic matter concentrations. However, observations of effects of metals and rate of recruitment to azoic sediments provide useful data on the processes underlying recovery. These results are placed in the context of other studies of the response of estuarine benthic communities to perturbations in order to provide a synthesis of the role of the various processes operating and their spatial and temporal scales.