POSTINDUSTRIAL POLLUTANT LEVELS IN CONTEMPORARY SEVERN ESTUARY INTERTIDAL SEDIMENTS, COMPARED TO PREINDUSTRIAL LEVELS

A set of 46 samples have been analysed for coal, copper, lead and zinc levels to determine the degree to which present-day sediments are enriched relative to their pre-industrial counterparts. Half (23) of the samples were obtained from contemporary mudflat sediments, distributed over the estuary, whilst the remainder were taken from the pre-industrial sediments from within the Rumney Formation. The analysis reveals a systematic enrichment of metals in present-day sediments of the order of 2-4 times those found in pre-industrial sediments, whilst coal varies widely from enrichment to depletion. This variation is taken to indicate the diverse history of coal production in this area, and the localized effects caused by small-scale industry and port activity.