Well, I tried three times to view the link, but all I got was "page not found"....whatever.
Lead, as far as I know, is not much of a threat from injestion while lying on a river bottom.
As far as dredging.....I just find it incredible that anyone would think that mining river bottom used by our already over-stressed fish populations as spawning and rearing grounds, as a viable means to supply income for themselves.....blows me away! And I consider the State's regulations and management horrific at best.

You may well be correct that sporties are next.....so what else is new? I still can't find anything to support your entire concept. You lose.