HISTORICAL CHRONOLOGIES OF SEDIMENTATION AND HEAVY-METAL CONTAMINATION IN STRANGFORD LOUGH, NORTHERN IRELAND

Abstract:Sediment coring for subsequent elemental analysis and radionuclide dating is an effective way to reconstruct sedimentation and contamination chronologies in sheltered marine environments. Of four sediment cores collected in Strangford Lough, three showed clear spikes in the mass accumulation of sediment in the late 1970s and early 1980s. These brief periods of heavy sedimentation also coincided with periods of conspicuous change in particle-size parameters in two cores. Monthly meteorological data for Northern Ireland suggest that wind speeds and rainfall were also above average for this period. However, the majority of the annualised meteorological data failed to correlate with the particle-size parameters or the sedimentation rate. Heavy-metal analysis indicated that most metals are near a predicted background concentration, although Cd appears to be particularly enriched, and Cd concentrations continue to increase in the most recent deposits. This study furthers our understanding of historical rates of sedimentation in Strangford Lough. The influence of anthropogenic activities on sedimentation dynamics is also discussed.