[seafarer]

When I still did deep-sea marine biology and ALVIN cruises, one of the most common things seen on the bottom of the ocean (in 1500-4000m depth) was aluminum soda cans, especially coke cans. Most ocean going commercial ships still simply toss all their rubbish over the side, so it has to collect somewhere. Not to mention the renderings of massive drift nets that seem to foul the north Pacific everywhere (I was amazed how often we used to encounter them - they seemed everywhere).

That, and a lot of Pacific rim countries still use barges to dump much of their land based rubbish at sea.