Not all.
An appalling amount winds up in the ocean. Having sailed between Hawaii and the US Mainland several times, I can tell you that a thousand miles off shore there is a huge concentration of trash in the water. It took us a week to sail through "The Garbage Patch" in 2012. Some of it is intentionally dumped in the sea, some of it just blows away from coastal cities and some of it is gear lost overboard from fishing boats. It was there before the Japan tsunami of 2011 but of course is worse now.