Just to add some more froth the the fire: I'm perusing "New Artist's
Handbook" (which is really very good). It tells us that "oil-soluble
phenolic resins are usually based on a mixture of linseed and tuna oil."
So now we have to look for a dolphin-safe icon on the varnish can? :)
Relevant to this and similar threads, I just stumbled upon
http://www.homesteadfinishing.com/htdocs/msds.htm which has MSDS pdfs for
several manufacturers' products (T&T, Waterlox, etc.)
"Keep your ass behind you"
vladimir a t mad scientist com
You are absolutely correct about the relatively small quantity of cobalt
exposure. The reason the EPA has no limit on cobalt in drinking water is
that it has not been recognized as a problem. At least, not yet. It seems
like every year, another limit is placed on some contaminant, for good or
The term "heavy metal" is a really soft term that was applied to just a
few metals many moons ago. Since that time, it has come to mean anything on
the Periodic table that is left after chopping off the appropriate groups
like halogens, alkali metals, etc. As a result, the term includes so many
metals that it is essentially worthless.
As for finishes being food safe once fully cured, that is correct. The
issue is the term "food safe". That means the finish can be in contact with
food. It does not mean that the finish is safe to eat. As was pointed out,
lead paint was banned because children were actually eating it. It also
happens that lead from various pigments can be leached out when in contact
with acidic food so it really was not "food safe". The metallic driers in
modern finishes are safe when used in a finish that fully cures and the
finish is not actually eaten.
I don't know of any maximum contaminant level (MCL) regulation that is
unreasonable. If a water source has an MCL violation, you can rest
assured that the concentrations of that contaminant are very high
compared to what is normally encountered with clean water.
Concentrations of cobalt are typically in the microgram/liter (ppb)
range for clean drinking water, so an MCL regulation would probably be
nearer the mg/L (ppm) range considering its low toxicity by ingestion,
if such a regulation were ever instituted. It would all depend on what
conclusions were on the study that prompted the hypothetical regulation.
But what I've been able to dredge up from the Net is that continued
ingestion of more than 30mg per day is required to see negative health
A useless media coined term. Gold is heavier in atomic weight and
denser compared to arsenic, yet it is non-toxic and inert. There are
many other examples. I don't see how manganese at 25 on the periodic
table and cobalt at 27 could be considered heavy metals, whatever that
means. Of course, Andy Dingley didn't mention that term in his post,
but others have in previous threads.
Yes, but in my worst case scenario I wanted to assume that part of the
finish is actually ingested. Yet even in this worst case scenario
exposure levels were in the microgram range. I think we can forget
about manganese entirely since both of the multi-vitamins in my house
have 2mg of manganese per tablet, a couple of orders magnitude greater
than my worst case scenario. Also the driers are used only in
polymerizing finishes and even if small chips of the finish were
consumed, it isn't at all clear to me that those polymers are digestible
or that the driers could be leached from them. So not only are the
driers safe for ingestion, the exposure amounts are at worst small, but
quite possibly negligible.
The EPA tends to overreact to preliminary studies. For example, the
recent lowering of exposure limits to methylene chloride is just one
example. At least there is some hope that the EPA will actually reevaluate
The term "heavy metal" has been in use way before the "media" could have
coined the term. It can be found in all sorts of analytical chemistry
textbooks that date back to before the 1940s and was used in the open
literature before that time. Way back, it actually did have something to
do the with density of a metal but it quickly became applied to all sorts of
metals. It definitely has nothing to do with a metal's atomic weight.
By the way, gold can be quite toxic when in something other than its
elemental form. Just ask anyone who has to take gold containing arthritis
treatment drugs. Keep in mind it is not so much the elemental lead that is
so toxic, it is what it rapidly turns into in the human body. There will
always be certain metals that are way more toxic than others because they
interfere with the human body's biochemical mechanisms.
I agree 100%. The amounts are so small as to be insignificant when
compared to accepted limits.
Yes, but those are some highly artificial organic salts designed to take
gold where no gold has gone before. I think it is misleading to compare
gold and lead toxicity. There is no comparison. But that is topic
drift. I think everybody has too much information now.
Fish? If you are a fisherman or hunter, you have
much more to worry about, especially if the
streams have any contamination from insecticides
and herbicides and the fields are sprayed with the
same. One fish out of the Snake River or any
other river used for irrigation would have a
larger dose of any "heavy metal" in organic form
than your salad bowl coating. Heck, eating
recommendations for Pheasant in some places is
down to 1 every 2 week or none for pregnant women.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.