great info kurzkaster!
as an antecdote, a friend of mine was fooling around with some spinning gear at the mouth of mink brook this past spring and got a walleye. of course he said he got a rash on his legs the next day and thought it was from the water treatment plant right on the other bank, but i dont buy it, i've been swimming downstream from there off of gilman island with no ill effects (but i suppose its all relative with me)
"Fishing is the most wonderful thing i do in my life, barring some equally delightful unmentionalbles, and not disregarding gluttony and booze. It's in the top five." -Jim Harrison