Persistence, Spatial Variability and Transport of Anthropogenic Coal Particles from Old Power Plants in the Nearshore Sediment

Abstract

[eng] This study addresses the persistence and dynamics of unburned coal fragments, within coastal sediments at the Bay of Palma (Mallorca, Western Mediterranean) for the period 1990 - 2010. This coal fragments relate to two coastal power plants in operation from 1859 to 1968. Two sediment-sampling campaigns have been developed; one in 1990 and another in 2010. Sedimentological and composition analyses show that local nearshore sediments consist of well-sorted medium to fine bioclastic sands, reaching 70% of the sediment budget. Nevertheless, almost 3.7% of the coastal sediments are coal fragments. The comparison of sediment properties for 1990 and 2010 survey samplings, show that the presence of coal fragments in nearshore sediment has increased from 2.9% to 3.7% due to re-working and fragmentation of original coal grains by alongshore currents and waves action. Spatial distribution of coal reports a south-eastwards transport that coincides with the main coastal current direction along the bay