"Mercury was used in the manufacturing of felt hats during the 19th century, causing a high rate of mercury poisoning in those working in the hat industry. Mercury poisoning causes neurological damage, including slurred speech, memory loss, and tremors, which led to the phrase "mad as a hatter".
From a recent online article:
“I just don’t buy the naysayers,” said Timothy Lariano, who didn’t want to hear that all his years of experience count for nothing. “I don’t believe in all the science. My dad and I have been fishing the Susquehanna for years, and although I think there could be some problems with the water due to farm runoff, the fish I catch are good eating.”
"Jonathan Kratzer, a friend of one of the participants, said he’s been fishing the West Branch for more than 30 years and “I know what they (the Fish and Boat Commission) have been saying about this river being impaired. I think there is a problem, yeah. But ever since I was a kid, I’ve been eating the fish from this river and I don’t feel like it will affect my health. I do look online at the advisories.”
Read the entire article here.
I am not a medical professional, and I do not know how wide-ranging the neurological damage of ingesting elevated levels mercury over long periods of time, say...30 years, might be.
However, I do know that ignoring science is not a wise course of action, so I might recommend some tests be done to ensure Messrs. Lariano and Kratzer have nothing to worry about.
Have a good weekend.