Trace element studies in Laucala Bay, Suva, Fiji

The trace metal distribution in the sediments of Laucala Bay, a coastal lag oon with a barrier reef and significant freshwater input, adjacent to Suva, the capital of Fiji (150000 people), was studied from the point of view of assessing the significance of anthropogenic sources relative to natural on es. Surface sediments from 25 sites in the Bay were analysed for particle s ize distribution, organic carbon and major (Si, Al, Fe, Ca, Mg) and trace m etal (Mn, Zn, Cu, Pb, Cd, Hg) contents, Suspended sediments from one site a nd shellfish samples from five sites were also analysed. The sediments were found to be mostly of terrigenous origin. Particle size distribution, orga nic carbon and major elemental composition of the sediments were generally related to location within the Bay. A significant natural source of trace m etals in the sediments is the suspended solids transported into the Bay by rivers. The spatial distribution of trace metals could not be fully explain ed by the particle size distribution and mineral composition of the sedimen ts. Contributions from anthropogenic sources were also suspected, but the d egree of enrichment from such sources is not great at the present time, (C) 2001 Elsevier Science Ltd. Ail rights reserved.