I met a lady there who lost her husband after five years of eating fish every
week. he never gave any attention to the warnings and died of cancer. There
are many stories like these from the locals near the river. Sledge from a spill
that happened in the early 1900's still exists on the bottom of the Ohio, also.
Nah, you’ve just gotta watch which waters you fish in (to eat from), not eat fish all the time, and mostly stick with eating the smaller fish. Granted, I would not eat fish out of the Ohio River on a bet. There are some really nice clean smaller lakes in S. Illinois and S. Indiana, too.
Most of the mercury in ponds and smaller lakes is actually from old coal burning plants and such, and much of it is slowly diminishing, with some new ponds actually showing quite low levels. (If in doubt I e-mail the fisheries guys and get the data from them.) An interesting fact is that most of the mercury in waters not contaminated years ago or by some particular local source is coming from, get this, China.
On the other hand, some of the locals are not too bright. In one area near us that was contaminated by an old coal power plant, the local fish & wildlife service put up signs warning of the mercury, but locals fished those ponds anyway. So, the fish & wildlife people exterminated all the fish, but the locals promptly restocked ‘em and commenced fishing again. Finally, the WMA (Wildlife Management Area) and the local bass club got together and built a really nice big pond with good access, so most people go there. The only thing I’d hesitate to eat out of there would be a large bass or (if it is still there) the 50 lb. blue cat from the river some guy claims to have put in that pond.