Most cruise ships burn low grade bunker fuel laden with heavy metals and other toxins. Some pollutants (not all) are removed by scrubbers that use sea water to spray down the air pollution. They return this sea water now laden with heavy metals and toxic particles back into the sea!  This causes dead zones and is horrendous for our shellfish.  Oysters, crabs and other seal life are a big part of our ecosystem and our economy. We don't want our precious Chesapeake Bay further damaged by these monsters of the sea.