I would assume that the problem of PCB contamination would be of much less concern off the coast. In the case of Puget Sound, greater quantities of PCBs and other contaminants have been dumped in a much more restricted area. Another problem is the sill and basin configuration of the Sound's bottom. The tidal flushing that would remove and disperse contaminants takes place only slowly, if at all, in the deeper basins, allowing the amount of contaminating materials to build up there.