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lead glaze hypothetical

updated wed 17 dec 03

 

Zoe Johnson on tue 9 dec 03


I have a "friend" who still uses a lot of lead glazed pottery from the 50's
and 60's both American and Mexican. This person is related to my children
(children in their 20's) and when they are over at his house, he is prone
to serving them liquids and food out of this pottery. How much lead
exposure do you get from one cup of coffee from a vibrant red earthenware
cup? And at the other end of the spectrum, if you eat all your meals from
lead glazed pottery, how much cumulative exposure do you get? This person
is quite a few bricks shy of a load as it is, did the lead cause it?
aggravate it? Are "modern" glazes made from frits any safer? So that we
could substitute new brightly colored glazes for the old stuff, even if it
is not food safe? This guy is nutty, getting nuttier all the time. He
loves his old stuff and says things like if it was good enough for my
father or if it was good enough for the Maya....
ZoeJ

John Britt on wed 10 dec 03


Zoe,

This is terrible. The guy is probably getting crazier from the lead! I
guess if it is good enough for dead Romans it is good enough for him! I
imagine he won't be around long anyway.

But your children should not even go over there. I don't know what age
they are by ingesting lead is far worse on developing children.

You might help him by taking a lead tester over and testing some of his
work.

John Britt

Zoe Johnson on wed 10 dec 03


The good part is the kids are old - 23 and 25. Right now, they are dumping
the coffee when offered on the ground
or down the sink, because they don't want to offend their dad. He is nuts
and is not a working potter. He does have lots of wonderful old pottery
purchased in native markets over many years. The kids are mostly wondering
if an occasional cup of coffee will hurt them. Their dad is just really
out there and kind of has the delusional belief that lead is good for you
and it is a government conspiracy to keep it out of the food supply and
gasoline.
zoej

--On Wednesday, December 10, 2003 7:27 AM -0500 John Britt
wrote:

> Zoe,
>
> This is terrible. The guy is probably getting crazier from the lead! I
> guess if it is good enough for dead Romans it is good enough for him! I
> imagine he won't be around long anyway.
>
> But your children should not even go over there. I don't know what age
> they are by ingesting lead is far worse on developing children.
>
> You might help him by taking a lead tester over and testing some of his
> work.
>
> John Britt
>
> _________________________________________________________________________
> _____ Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.

Zoe Johnson on thu 11 dec 03


Part of the reason I was wondering about dangerous levels of lead, is that
many government standards are not trustworthy, way to high or way to low.
Arsenic in water is a good example. Much of New Mexico has volcanic rocks
that contribute arsenic to the water naturally at much higher levels than
are allowed by government standards, so big new plants will need to be
built to remove the natural occuring arsenic. Reducing the arsenic will
probably prevent a few fatalities from cancer. This is maybe good, but
more people will probably be killed during the construction of the plant
and trucking in construction materials (the probability that fatal
accidents will occur at certain rates in certain activities has been well
demonstrated), so maybe it's not so good. My son who is was studying
safety engineering, says that safety regulations are full of things like
this.

And yes, my friend (my ex), is crazy and getting crazier by the minute. I
wonder how much is lead, and I would love to know just how much lead
leaches into 1 cup of coffee from a new cup and from one used for several
years. I would like to know numbers not just that something has been
labeled bad. Before we take my ex's dinnerware away from him, I need to
know how dangerous it is, because just last May, he attacked my son with a
shovel because he threw away a broken plastic basket. I need to figure out
what is the greater danger here.
zoej

Ron Roy on thu 11 dec 03


Hi Zoe,

I agree with John Britt - educate your children - there is lots of info on
the internet about lead posioning - symptoms for instance - and they should
tell their doctor about their exposure - there are ways to check lead
levels.

You can also read about the effects of lead poisioning in Monona's book -
The Artists Complete Health and Safety Guide - by Monona Rossol - there is
a third edition.

This person should also be warned - there are ways to get the lead out.

RR

>I have a "friend" who still uses a lot of lead glazed pottery from the 50's
>and 60's both American and Mexican. This person is related to my children
>(children in their 20's) and when they are over at his house, he is prone
>to serving them liquids and food out of this pottery. How much lead
>exposure do you get from one cup of coffee from a vibrant red earthenware
>cup? And at the other end of the spectrum, if you eat all your meals from
>lead glazed pottery, how much cumulative exposure do you get? This person
>is quite a few bricks shy of a load as it is, did the lead cause it?
>aggravate it? Are "modern" glazes made from frits any safer? So that we
>could substitute new brightly colored glazes for the old stuff, even if it
>is not food safe? This guy is nutty, getting nuttier all the time. He
>loves his old stuff and says things like if it was good enough for my
>father or if it was good enough for the Maya....
>ZoeJ

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513

Lee Love on thu 11 dec 03


Taking zinc supplements is one way to help keep the body from absorbing
heavy metals from the environment. Sorry, I don't know the dosage. But
you might be able to find it on the web.

--
Lee In Mashiko, Japan
http://Mashiko.org
Web Log (click on recent date):
http://www.livejournal.com/users/togeika/calendar

pdp1@EARTHLINK.NET on thu 11 dec 03


Hi Zoe,



It would seem his reasoning is compromised in some way.


But quite in keeping with the larger national inclinations
and passtimes at
any rate, in spirit if not in exact detail.


Public school graduate was he? ( most are..)


Anyway...



Best wishes,

Phil
Las Vegas

----- Original Message -----
From: "Zoe Johnson"
To:
Sent: Wednesday, December 10, 2003 7:42 AM
Subject: Re: Lead Glaze Hypothetical


> The good part is the kids are old - 23 and 25. Right now,
they are dumping
> the coffee when offered on the ground
> or down the sink, because they don't want to offend their
dad. He is nuts
> and is not a working potter. He does have lots of
wonderful old pottery
> purchased in native markets over many years. The kids are
mostly wondering
> if an occasional cup of coffee will hurt them. Their dad
is just really
> out there and kind of has the delusional belief that lead
is good for you
> and it is a government conspiracy to keep it out of the
food supply and
> gasoline.
> zoej
>
> --On Wednesday, December 10, 2003 7:27 AM -0500 John Britt
> wrote:
>
> > Zoe,
> >
> > This is terrible. The guy is probably getting crazier
from the lead! I
> > guess if it is good enough for dead Romans it is good
enough for him! I
> > imagine he won't be around long anyway.
> >
> > But your children should not even go over there. I
don't know what age
> > they are by ingesting lead is far worse on developing
children.
> >
> > You might help him by taking a lead tester over and
testing some of his
> > work.
> >
> > John Britt
> >
> >
____________________________________________________________
_____________
> > _____ Send postings to clayart@lsv.ceramics.org
> >
> > You may look at the archives for the list or change your
subscription
> > settings from http://www.ceramics.org/clayart/
> >
> > Moderator of the list is Mel Jacobson who may be reached
at
> > melpots@pclink.com.
>
>
____________________________________________________________
__________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your
subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached
at melpots@pclink.com.

Steve Slatin on thu 11 dec 03


Phil --

Lead in glazes is an interesting question. The majority of
lead glazes are safe. They are also not often enough
tested, and so there is some risk.

The comment a few messages back about being crazier than the
Romans is an interesting one. Pliny the Elder (IIRC) counseled
the Romans who could afford it to cook in pots of lead. Their
exposure must have been massive, and it's interesting in a way
that the Empire didn't fall apart more rapidly than it did. (Or
perhaps no one listened to Pliny.)

In any event, the real issue is with leaching glazes and acid
foods. That creates some real exposure. I don't have any lead
pottery that I know of, and won't have lead in my
studio, even in a frit, for safety's sake. If I allowed a few
lead-bearing items into my home, though, the risk to my family would still
be quite slight.

The risk is much greater for young children. Some years back I saw some
studies on this, and it seems for some reason their bodies retain a much
larger percentage of the lead they are exposed to than adult bodies do.

My recollection on this last point is not clear, but I seem to remember
having read once about 10 years back that the single greatest cause of lead
exposure in the US (now that lead is out of gasoline) is from lead-soldered
water pipe and lead water supply pipes. I don't have a clear enough
recollection of this to provide any details, though.

As far as education goes, I've not noticed a significant difference in
weirdness of public school vs. private school graduates in the US. I have
noticed different characteristics between east coast and west coast, and
between urban and rural. I suspect that there are enough wackos of all
stripes in the US today from every background that it's essentially
impossible to attribute their attitudes and actions to any single part of
their background.

-- Steve Slatin

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of
pdp1@EARTHLINK.NET
Sent: Thursday, December 11, 2003 1:15 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Lead Glaze Hypothetical

Hi Zoe,



It would seem his reasoning is compromised in some way.


But quite in keeping with the larger national inclinations
and passtimes at
any rate, in spirit if not in exact detail.


Public school graduate was he? ( most are..)

Jan L. Peterson on thu 11 dec 03


I was born and raised with smelter smoke, and natural leaded soil. The worst
lead is in soil 24" down, with the soil deepening an inch every twenty years,
that means that before mining ever hit this region. Meaning, again, that it
got there possibly from an extremely large volcanic action. I have now, a lead
count of 5%.
The children who made lead come to light and be intensely studied, were kids
who ate the soil. Ingested it because there were no parents cooking meals, or
any meals to cook. The kids parent were drinkers of the highest water.
My Grandson, back East developed a lead count of 25%, because his father
worked in an ammo manufacturing plant, and was not taking showers and changing
clothes before he picked the boy up from Daycare.
We have natural lead in our waters and our soil, because we are a metal and
mineral-rich area. Usually, over 35% of our classes are Honor roll, and possess
higher IQ. that 124. So, all we can figure is these children's lives were
jeopardized by parents who neglected them, and they had to eat the soil for
survival. I do not recommend dirt as a diet for anyone.
People think, new ones to the area, that the Smelter Smoke killed the
hillside trees. If it killed those, it should have killed trees in yards, grass, and
flowers, and all kinds of garden goods. The forget that when you mine
underground, you have to prop those tunnels. And, you do it with wood. You can go into
any mine on a certain level, and walk this whole Valley underground. There
are thousands and thousands of miles of tunnels. You would also have thought our
miners would have died of lead poisoning. They didn't. As far as I know,
there were no higher counts of cancers or illnesses than anywhere else. Accidents,
there are always mining accidents.
I can remember the smelter smoke, on particular days to take the breath right
out of you, but I think that you are far more likely to be in danger from
lead glazes and paint, that I am living here.
I would not handle refined lead without gloves, and I wouldn't go near lead
dust without a mask, either. Be careful, and read your labels! Jan, the
Alleycat

pdp1@EARTHLINK.NET on fri 12 dec 03


Hi Zoe,



I was being playful the other day..it was my mood at the
moment.

The Water is a consideration, as you mention.

Is he on a Well?


Many Mining areas have aquifers as come up through old
Mines, then run out of them into whatever Water table they
may get into. Such Water can be very toxic so far as Metals
and other undesireable things. Aresnic for one...on and
on...


Depending on the length of time the Coffee is in the
(suspect) 'Cup'...depending ( I would think) on the ph or
alcalinity of the Coffee as he makes it, the brand he buys
and so on...his method, the intrinsic chemistry potential of
the particular Water used...

What of the Lead content of the materials of the Coffee
Maker? Is it a 'import' sort of "mr-coffee" thing? The Glass
Caraff and all...?

Endless...


Maybe the 'Cups' are significant...then again, maybe not.
There may be other, maybe many other vectors of equal or
greater possibility...



Phil
Las Vegas
----- Original Message -----
From: "Zoe Johnson"
To:
Sent: Thursday, December 11, 2003 8:29 PM
Subject: Re: Lead Glaze Hypothetical


> Part of the reason I was wondering about dangerous levels
of lead, is that
> many government standards are not trustworthy, way to high
or way to low.
> Arsenic in water is a good example. Much of New Mexico
has volcanic rocks
> that contribute arsenic to the water naturally at much
higher levels than
> are allowed by government standards, so big new plants
will need to be
> built to remove the natural occuring arsenic. Reducing
the arsenic will
> probably prevent a few fatalities from cancer. This is
maybe good, but
> more people will probably be killed during the
construction of the plant
> and trucking in construction materials (the probability
that fatal
> accidents will occur at certain rates in certain
activities has been well
> demonstrated), so maybe it's not so good. My son who is
was studying
> safety engineering, says that safety regulations are full
of things like
> this.
>
> And yes, my friend (my ex), is crazy and getting crazier
by the minute. I
> wonder how much is lead, and I would love to know just how
much lead
> leaches into 1 cup of coffee from a new cup and from one
used for several
> years. I would like to know numbers not just that
something has been
> labeled bad. Before we take my ex's dinnerware away from
him, I need to
> know how dangerous it is, because just last May, he
attacked my son with a
> shovel because he threw away a broken plastic basket. I
need to figure out
> what is the greater danger here.
> zoej
>
>
____________________________________________________________
__________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your
subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached
at melpots@pclink.com.

Ron Roy on mon 15 dec 03


I don't think the majority of lead glazes are safe - perhaps those used by
industry are - because they are regulated. Those made by studio potters are
not I would think.

I would also be interested to find out if those sold to studio potters
would be either - many glazes manufactures don't sell lead glazes anymore
and when they do they often say - not for use with food.

It is interesting that many potters still think - if the glaze is made with
a lead frit - it will be safe - nothing could be further from the truth.

RR


>Lead in glazes is an interesting question. The majority of
>lead glazes are safe. They are also not often enough
>tested, and so there is some risk.

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513

iandol on tue 16 dec 03


Dear Friends,
I think Ron Roy's view on this should be heeded.
I have no doubt that in a secure industrial setting where there is =
Responsible Management and Quality Control over all aspects of =
Production, Design and Research that products will conform to the laws =
of the land in which products are made. Government rules which quantify =
the limits of Lead Release give a window of opportunity in which =
commercial businesses can operate.
But without those strictures, checks and balances the caveats kick in.
Always remember that lead compounds are affected by reducing conditions. =
Some of our recent discussions support the idea that even in an electric =
kiln reduction will or may happen.
So we have to accept that even if Lead Frits and Silicates are used as a =
way of avoiding oxides and carbonates (which are a hazard for workers) =
there is no guarantee that the final glaze will be "safe".
It is well reported that copper compounds aggravate the solubility =
problem, and as I have said before, we have very little concrete =
information about the destabilising effects of any of the colourant we =
use. The Chemistry is not described.
Best regards,
Ivor Lewis. Redhill, South Australia