In December 2009 seven Sperm whales were found stranded on the beaches of Gargano on the Adriatic Sea. Necropsies on two of the whales found that their digestive systems were choked up with plastic, so the headlines at the time suggested that the plastic was the cause of the tragedy.
But the simultaneous mass stranding did not entirely square with the symptoms. While one theory behind mass strandings is that community animals will follow sick community members to beach themselves together, this event was concurrent to a seismic airgun surveys in the area.
It is unclear in the Italian Informar Per Resistere article that the necropsies revealed coronary embolisms. But deep-diving whales will develop fatal gas emboli if they are frightened and surface too fast. This pathology would be more consistent with a stranding of this nature, where the whales arrived dead on the beach.
Of course the story is mildly ambiguated by the fact that Informar per Resistere is an anti-Berlusconi paper which never misses a chance to point out the foibles and failures of the Italian Prime Minister.
On the other hand; whether the whales were choked by plastic or killed by noise impacts, this tragedy points out the expense of our living in a climate of human negligence.