Effects of long-lasting massive dumping of dredged material on bottom sediment and water turbidity during port expansion works

The effects of massive dumping dredged material were studied during and after the last large Barcelona port expansion. A benthic tripod equipped with a current meter, turbidimeter video camera was deployed at edge shelf dumpsite. Additionally, sediment cores taken before, location. Previously, samples in expansion area. Dumping generated frequent (10–19 per day), high (>203.2 mg L −1 ) short (50–90 min) suspended concentration peaks along shock waves that increased currents velocities. dumped formed thin laminated deposit accumulated beyond limits This finer had lower trace metal content than previous dumpsite surface from Unconsolidated left available to be resuspended advected, generating higher ambient concentrations (0.8–15.0 before (0.4–2.0 ), which lasted several days. Results this work suggest end low dispersive environments, such as on continental shelf, turbidity should continue monitored until recovery natural values. characteristics bottom periodically controlled if spilled outside its boundaries. Environmental guidelines for dredging activities include specific actions long-lasting episodes regarding their spatial extent, considering by dumping, also temporal evolution completion. • water seabed affected dumping. 502 53 mud extending limits. Mixing dilution decreased metals levels Guidelines environments.