Chronological reconstruction of metal contamination in the Port of Maó (Minorca, Spain)

► The Port of Maó is an example of progressive sediment pollution around a harbour. ► Submarine outfall implied a clear decrease in metal concentration in sedimentary record. ► Misleading sediment quality conclusions could be drawn by sampling only the surface sediments. ► Metal concentrations are higher than the recommended concentrations for acceptable sediment quality.