I have totally lost faith in recycling anything other than aluminum/glass/some paper in single stream recycling.
Is this verified? I have a theory (and haven't bothered to investigate so that one's on me) that a lot of recycling is just parceling it up and exporting it to landfill or incinerators abroad.
Mind you, the plastics found in the ocean should be traceable back to their origins; they may be from e.g. Asian rivers, but if the origin is from the US or Europe you know whose fault it is.
The solution is to have more regulations about where US waste processors can send recycling to prevent sending to dubious places that throw it away. It is better if recycling goes to the landfill in US instead of playing hot potato.