Trace metals: inputs, sedimentation and accumulation in San Vicente Bay, Chile.

The present study deals with sediment dynamics affecting sediment-associated metal distributions in an embayment system experiencing pollution from coastal industries. Sedimentary metal content may originate from diagenetic processes of foundation rock on the bottom, allochthonous minerals from natural sources, and metals from industrial effluents along the coast. The study presents experimental estimations of quantities of metals entering the bay in industrial waste-water, measurements of metal content in particulate material captured in sediment traps, and metals distribution in surface sediments. Quantitative estimations of metals entering the system in industrial effluent showed the relation Pb > or = Zn > Cu > Cr > or = Ni > Cd. That of metals associated with particulate material from traps was Zn > Cr approximately equal to Cu > or = Pb > Ni > Cd and the abundance of metals in sediments was Zn > Cr > Cu > Pb > Ni > Cd. Finally, rates of bottom sediment accumulation are estimated in relation to the time of residence of water in the bay. The experimental data on sedimentation and sediment abundance were consistent with field observations on distribution and accumulation at sites of major sedimentation in this bay.