Est. 1998 — 27 years of woodworking knowledge
Re: mercury
Hank Knight
Isn't mercury one of the heavy metals that accumulates in the body over time? It is absorbed through the skin. Infrequent, short term contact is not sufficient to produce a harmful dose; but with long term or frequent contact mercury will accumulate and produce a toxic, potentially fatal dose. Arsenic is another killer with the same properties.
Re: Parathion
Hank Knight
The husband of a good friend owned an agricultural supply house. He was stacking bags of parathion powder in the warehouse when one of the bags slipped off the stack, landed at his feet, broke open and covered him with dust. He went home, showered and changed clothes. He was dead the next morning. Yes, it's nasty stuff.
clarification
Bill Tindall, E.Tn.
Isn't mercury one of the heavy metals that accumulates in the body over time? It is not a one way street. If the dose is accumulative the result will be accumulative. When the dose stops the body slowly begins to be rid of the mercury, but the ridding is slow.
It is absorbed through the skin. Some mercury compounds are. Methyl mercury is a bad one. It goes through the skin barrier promptly and death is certain if the dose is sufficient. Mercury metal does not go through the skin. But it has a vapor pressure. If enclosed in a room with mercury over a long time enough mercury could enter the body by vapor to become toxic. Miners recovering gold by heating a mercury amalgam to drive the mercury off die young.
Infrequent, short term contact is not sufficient to produce a harmful dose; but with long term or frequent contact mercury will accumulate and produce a toxic, potentially fatal dose.
I caught it...
John in NM
Though in fairness it took a couple readings 
The great scientist Robert Hooke drank mercury *LINK*
Keith Newton
As well as some elixir that he made using iron, thinking it would improve his health. While reading about Isaac Newton, I think I read Hooke may have gone a bit loony in the end. I'm not trying to downplay the hazards of this or any chemical.
However, I'm like many of you, I also had a little pill bottle of mercury as a kid, and can recall chasing flies around our garage pumping one of those sprayers that looked like a bicycle pump with a can crossways on the end. I was trying to shoot them out of the air, while I followed along running through the cloud of DDT.
It took Rachel Carson writing "Silent Spring" to bring to awareness the real hazard from DDT was not to us, but to our avian friends that we share this planet with. We almost lost our National symbol the Bald Eagle as well as others like Peregrine Falcon.
The chemical industry through advertising over the long period of our lives has lulled us into believing that we need to poison all the lowly creatures that live in our grass and eat the leaves of our trees. But never do they mention that if you kill all the insects either by poisoning them, or choosing plants from another part of the world that our local insects can't digest, we are creating a "barren food deserts" for our birds that need those insects to feed their babies.
We are loosing 4% of our migratory birds each year. Almost all bird species feed their young caterpillars that need the plants they evolved with to exist. Think about that for a minute. That is 40% fewer than just ten years ago. Will you miss those species when they are gone?
Here is a great video done by Doug Tallamy author of "Bringing Nature Home"if you haven't read his book.
https://www.youtube.com/watch?v=3wzcz8dWyBc
neither were chemists, more on mercury
Bill Tindall, E.Tn.
In fact Newton devoted a considerable part of his life to pursuing Alchemy in spite of the fact that it was largely discredited by his time.
Mercury chloride was the only treatment known for syphilis until the discovery of antibiotics. It was an essential ingredient of the Lewis and Clark expedition "first aid kit". The men did more than hike and hunt.
Dental amalgam is silver plus mercury, which renders the mercury essentially insoluble. If it isn't dissolved it isn't toxic.
On the topic of birds, we have gobs of blue birds, maybe as a result of the dozen houses we have out. We eat on the back porch when weather is pleasant. The blue birds station in the maple trees. When a bug moves on the lawn below they swoop down and snag it. Above the swallows hunt the skies. It is like watching an air show.
Re: Mercury Accumulation
Larry Clinton At Frankfort, (Central) Indiana
Several years ago the Scientific Community & Media (both mistaken or lying as usual) stated that Mercury was accumulated in the Human body and even casual exposure would build up to a toxic dose over years!
They also stated Swordfish (and maybe other fish) would have lethal results if you ate them regularly.
This caused many upper east coast fishermen to go broke some lost their boats and even homes!
A year or so later the Smithsonian Institution announced that they had a project that had been going on for years whereby volunteers gave a tissue sample periodically during their life for analysis and testing. When they tested the Mercury in these samples they found the percentage of Mercury increased AND DECREASED during their life.
Of course little of this was broadcast so guess the public still trust the "scientists". During my life I have seen the Media almost cause panic due to the dire warnings of said "professionals". These include Love Canal (PCB's).
Ozone hole (cost billions to chance just the Air Conditioners), try investigating this now!
Climate Change (YEP it is a periodic happening last recorded before the Industrial age)
There are others like the warning during the start of the automotive and railroad starts about "man will die if they travel at XXX speed!
St my age I take everything broadcast or foretold with a Salt shaker full of salt. Scientists rely on being "published" to retain their employment and/or obtain grants so I am sure not all are real careful about proving their predictions!!