Largest source of electrical pollution will be the 500-1500 amps @ 50V-110V DC electrical current flowing into the seawater around warships, cargo ships, barges and cruise ships to protect the metal hull from oxidation/corrosion.  Radars & antennas will also induct electrical current into the surface of the seawater.  Cetaceans are dying around the shipping lanes.

Whales are dying off the coast of Kerry, and no one seems to know why