HISTORICAL CHANGES IN MERCURY CONCENTRATIONS IN THE MARINE ECOSYSTEM OF THE NORTH AND NORTH-EAST ATLANTIC-OCEAN AS INDICATED BY SEABIRD FEATHERS

1. Body feather samples from preserved study skins held in museum collections and from contemporary specimens of a range of species of adult seabirds from the north and north-east Atlantic were analysed for mercury in order to assess historical trends in contamination of the marine environment with this toxic heavy metal. 2. Problems with the contamination of samples through the application of inorganic mercury to many study skins as a preservative were overcome by methyl mercury extraction (Thompson & Furness 1989a,b). 3. Fulmars Fulmarus glacialis (L.) from both St. Kilda and Shetland/Orkney exhibited significant declines in mercury concentrations associated with pronounced dietary change over the study period. 4. Other species analysed showed a general increase in mercury burdens, particularly towards the south and west of Britain. 5. Increased pluvial deposition of atmospheric mercury over specific oceanic areas, associated with jet-streams and the pollution of the northern hemisphere by mercury, is suggested as being a likely cause of the observed trends. 6. The use of time-series of feather samples, coupled with the extraction method for methyl mercury used in this study, offer great potential for elucidating changes in the mercury contamination of other environments.