Where does the plastic and other marine debris come from?
Marine debris can enter the ocean in a variety of ways. From land, trash may be carried to the ocean in rivers or storm and sewage drains, swept from the beach by waves and surf, or blown offshore by winds, especially during heavy storms. Trash may also come from ships or offshore platforms, although dumping of plastic at sea has been banned since 1988 (by MARPOL Annex V of the International Maritime Organization). We don’t know how much marine debris enters the ocean, or whether most of it comes from land or from vessels at sea. These are very difficult questions to answer because the sources are so widespread.