Cwdjrx _ wrote:

> I knew that use of chromium salts had been restricted, but I am
> surprised that it has even extended to the lab for cleaning solution.
> The concern probably is that the chromium salts will be flushed down the
> drain and polute a river from which drinking water is drawn downstream.

Correct. How universal the ban is I cannot say, nor at what level the
proscription arises, but I know of no researcher who stills uses chromate
cleaning solutions.

>
> In the lab, chromium salts are one of the less bothersome compounds that
> one works with. At one time I worked with several metallo-organic
> compounds including those including chromium, mercury, vanadium, nickel,
> etc. Some of the mercury compounds are especially toxic. Some can easily
> be absorbed through the skin, and it takes very little to send you to
> the morgue.

Indeed! Small organomercurials are incredibly dangerous things (witness
Minamata for an exceptionally tragic RL demo). Within the last two years,
a Chemistry Professor (NMR) died from mercury poisoning produced by a
dimethylmercury NMR standard. She was wearing two layers of latex glove,
but a drop spilled on her glove traveled through both layers and skin fast
enough to kill her from acute heavy metal toxicity. FWIW,
trimethylstannanes are every bit as bad for us organikers and are volatile
to boot!

>
>
> I have been retired a few years, so I did not hear about the ban on
> cleaning solution in labs. I did read that a local petroleum company had
> to quit discarding photographic solutions down the drain without
> treatment, because of the silver content.

Silver as a pollutant? Most people would gladly deal with that little
problem, I think. Perhaps they were using cyanide in their processing?

> I actually did very little
> lab wet chemistry except early on. I was one of those people who was
> accused of trying to get a physics degree in the chemistry department,
> since most of my work involved complex instruments, computers, math, and
> such.

I was one who spent half my time at the computer and half in the lab.
Still do today, matter of fact. Unless you took early retirement, you must
have been among the first generation of scientist to use computers (or I
can't do simple arithmetic).

>
>
> I do find it amusing that even the smallest traces of some things the
> public thinks of as "chemicals" are banned.

Even worse, the word "chemical" itself is now a perjorative, despite the
reality that we are nothing but a huge collection of chemicals assembled in
a particular way!

> Yet people continue to use
> smoked and fire-seared meat when it is well know that smoke and charred
> meat contain a variety of carcinogens.

Ah, but Bruce Ames (inventor of the Ames test for "carcinogenicity") has
shown that even a banana will contain over a hundred different
carcinogens. This in turn has raised the question of whether we as
organisms have evolved to detoxify certain mutagens in our diet. Animal
studies have lent support to that idea, though even a rat is only a so-so
model for human digestion and metabolism. So, despite the potent
mutagenicity of benzo[a]pyrene in soot, there is little to no evidence of
its ability to cause cancer in humans. One argument is that 10-20,000
years of cooking food over open fires has weeded out the susceptible
individuals from the population. Now, if only we could get rats to BBQ
we'd have a strong answer! ;-)

> It seems that if something is
> "natural" there often is little concern. Yet botulism toxin is natural
> and only a small bottle of it would be enough to kill thousands, if not
> millions, of people. Or getting back to wine, too much alcohol can
> produce undesirable long term health effects, but most do not cry out to
> ban wine because a few abuse it and harm their health. Of course I am
> well aware that where I live there is a small minority that would ban
> all alcohol and send sellers and users to jail, if they had their way

And alas in this country "natural" now carries with it an aura of
healthfulness, hence the advent of "nutraceuticals" as an essentially
unregulated bastion of quackery and charlatans. Chemophobes of the world
beware!

Mark Lipton