Human health effects of ocean plastic pollution?

In September 2014 I attended the Woods Hole Oceanographic Institution (WHOI) Ocean Science Journalism Fellowship. One of many scientists we were introduced to was Tracy Mincer, whose research into microbial communities on marine plastics eventually led me -- via a route I can't quite recall -- to the the subject of this story: potential human health effects of marine plastics. I interviewed him at the very early stages of sussing out this angle, but I ended up so far from where I began that I didn't end up using any of his quotes or research. I guess that's a sign of a good story: I chased it and watched it evolve and take shape, rather than setting out with a preconceived notion of the storyline. What I ended up with was a piece about research and the state of the science, rather than any definitive answers. The evidence to date is concerning, but many pieces remain missing. In the end, it seems, there's a good chance that marine plastics are playing some role in distributing chemicals and environmental pollutants throughout the foodchain, which we end up ingesting through seafood.