Yeah, I've heard of that but I don't know how much you'd have to eat but heavy metals are stored in the body and cannot be excreated so it'd be a case of over time the heavy metal levels in the body would rise to a toxic level.
These metals are due to pollution in the seas being consumed by organisms which are then consumed by bigger organisms, which are then consumed by bigger organisms....you get the idea....we are at the end of this food chain.
I'll have a dig around and see if I can find anything more 'concrete' on the matter.
PS...
Tuna is like cat food so I'M alright!!!!
