PCB Levels in Farm-Raised Salmon

Just saw this link. Some scientists are claiming that farm-raised salmon poses significant risk of PCB exposure. Anyone know any more about this?

Here’s the story linked from yahoo:

BB, no, I don’t know anything more about it. I always thought PCB exposure came from the ocean and from fish higher up the food chain eating smaller fish that were contaminated by/with PCB themselves.

If it is an issue, we’ll see more of it, I’m sure.