Sentence:  Buried within the Mediterranean <WSD>littoral</WSD> are some seventy to ninety million tons of slag from ancient smelting, about a third of it concentrated in Iberia. This ceaseless industrial fueling caused the deforestation of an estimated fifty to seventy million acres of woodlands. 
Meaning of the word marked with <WSD> tags:  The zone of a coast between high tide and low tide levels.