AREAL DISTRIBUTION OF SELECTED POLLUTANTS IN CONTEMPORARY INTERTIDAL SEDIMENTS OF THE SEVERN ESTUARY AND BRISTOL CHANNEL, UK

A series of 150 samples from the contemporary intertidal zone of the S evern Estuary and Bristol Channel have been analysed for levels of cop per, lead, zinc, rubidium, and particulate coal debris to investigate the present pollution status of the system. The analysis reveals a sys tematic streamwise variation in pollution concentrations which is take n to reflect a combination of land-based pollutant inputs and the rewo rking of pollutant-rich sediments from the erosion of salt marshes alo ng the margins of the estuary. This streamwise variation demonstrates a downstream decrease in concentration, superimposed on which are nine areas of contemporary pollutant input with regard to metals but non r elating to coal. The occurrence of coal in modern intertidal sediments at levels significantly higher than the underlying pollution trend is only possible via the reworking of anthropogenically derived material stored in the intertidal sediments of the system and from a wreck loc ated offshore.