One of me assignments in my instrumentation training was to overhaul a large characterized bell flow instrument. It contained 2 or 3 quarts of mercury.
Bill
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"Why not the best?"
Jimmy Carter
I once lived in the North Louisiana / Southern Arkansas region and there was (and is) a big rhubarb about mercury in the fish caught in local rivers. The rivers there don't drain any areas where there are a lot of minerals nor are there a lot of coal fired power plants which now seem to get the blame for all the mercury that exists in the land and the prevailing wind is off of the Gulf so that can't be blamed.
However, that region was one of the very first natural gas fields to be discovered in this country and my personal belief about the amount of mercury present is that it came from those old style kidney shaped flow meters like the one that Bill mentions above that were present everywhere throughout the gas field. Plenty of those either had the mercury spilled as it was handled, or in the case of some (and I have seen this in many plants - mostly paper mills - in the region) when the temperature got cold, and they froze and burst the mercury spilled out.
It rarely gets very far below freezing in that area, but when it does, it takes a toll on exposed piping. Back about 30 years ago, before electronics, the flow transmitters were all mercury pot or ring balance types. Paper mills in the area used to take their major outages over Christmas when they were paying the operators and staff to be off anyway until one Christmas some time in the late '80's when they were all down and an unexpected and severe cold snap (cold for that region) rolled in and temperatures got down to 6 degF, a record for the region I think. You could hear these old cast iron mercury filled meters going off like cannon shots all over the stone cold mill. I still remember it. There was nothing that could be done about it but just listen to all the mayhem. It was weeks before they were able to get back up.
Point being, lots of mercury got spilled that day alone and I doubt that back in that day that was seen as much of an issue other than the replacement cost of the instruments that were destroyed and the excessive down time. This mill drains right into the river in question....... And there were several paper mills upriver just like it. Go figure why the fish have mercury in them today.
