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Which glycol? There are glycol ethers also.
In '97 the petitioners withdrew their request for the EPA to delete EG from
the toxic reporting requirement.
They published their findings tho it was moot. I didn't search for later
action.
Exerpt below:
bc
P.s. curiously, a small amount of methanol is given to those suffering
ethanol poisoning. This has a similar effect to etOH described below.
http://www.epa.gov/fedrgstr/EPA-TRI/1997/May/Day-07/tri11902.htm
C. Human Toxicity Evaluation
The inherent toxicity of ethylene glycol is low relative to several
of its metabolites. The evidence for this comes from clinical studies
and laboratory investigations (Ref. 4). Ethanol is a competitive
inhibitor of alcohol dehydrogenase (ADH), the first enzyme in the
ethylene glycol metabolic pathway, and is very effective in treating
animal and human ethylene glycol poisonings. If treatment is started
early enough, the metabolic acidosis and renal failure discussed below
can be prevented.
1. Inhalation toxicity. Two inhalation developmental toxicity
studies have been conducted by the same group (Refs. 17 and 18). In a
whole body exposure study (Ref. 17), mice and rats were exposed to
ethylene glycol aerosols of 150, 1,000 or 2,500 milligrams per cubic
meter (mg/m3) for 6 hours/day on gestational days 6 through
15. The actual measured concentrations were 119, 888, or 2,090 mg/
m3. In rats, maternal toxicity occurred only at the highest
concentration and was indicated by a significant increase in absolute
and relative liver weight. In rats, evidence of prenatal developmental
toxicity (reduced ossification in the humerus, zygomatic arch, and the
metatarsals and proximal phalanges of the hindlimb) was observed at the
two higher concentrations. In mice, incidences of prenatal
developmental toxicity were increased at the two highest concentrations
and included malformations in the head (exencephaly), face (cleft
palate, foreshortened and abnormal face, and abnormal facial bones),
and skeleton (vertebral fusions, and fused, forked, and missing ribs).
The No Observed Adverse Effect Level (NOAEL) for maternal toxicity in
rats was 888 mg/m3 and in mice was 119 mg/m3. The
NOAEL for developmental toxicity in rats was 119 mg/m3 and
in mice was below this concentration.
A major confounding factor in this study was the deposition of a
detectable quantity of ethylene glycol upon the animals during
exposure. The animals could have received the chemical via the oral
route by preening or by dermal absorption, although much less would be
taken in via the skin. Analysis of the chemical on the fur of rats and
mice after the exposure period at the highest concentration indicated
that much of the chemical dose (65-95 percent) was potentially derived
from ingestion after grooming.
To address the potential confounding factor of multiple exposure
routes cited above, a further study used nose-only exposure of mice to
500, 1,000, and 2,500 mg/m3 of ethylene glycol aerosol for 6
hours/day on gestational days 6 through 15 (Ref. 18). Results from the
positive control (whole body exposure to 2,100 mg/m3)
confirmed the results from the previous study. In the nose-only
portion, the two higher concentrations produced increased kidney
weights in the dams. At the highest concentration, fetal weights were
reduced and fetal skeletal variations and one fetal skeletal
malformation (fused ribs) were increased. The developmental NOAEL for
nose-only inhalation exposure was 1,000 mg/m3; the maternal
NOAEL was 500 mg/m3. The developmental NOAEL in this study
was at least 10 times the whole body value since a NOAEL was not
established in the previous whole body inhalation study but was less
than 119 mg/m3. The maternal NOAEL was approximately five
times the previous value. This nose-only exposure study indicates that
most of the adverse effects seen in the whole-body exposure study were
due to systemic exposure from noninhalation routes; however, as
discussed above, adverse effects were seen in the nose-only exposure
study.
The toxicity data strongly indicate that ethylene glycol is much
less toxic than its metabolites; however, it is not known if ethylene
glycol might act directly on embryos. The available literature does not
provide adequate data to allow definitive conclusions concerning
ethylene glycol's toxicity to embryos (Ref. 4).
2. Oral toxicity. Ethylene glycol is expected to be absorbed
through the skin and from the lung and the gastrointestinal tract.
After absorption, it is expected to enzymatically oxidize to oxalic
acid, glycolic acid, glycolaldehyde and carbon dioxide. The aldehyde
metabolites are believed to be responsible for neurotoxicity and the
oxalic acid metabolites for renal toxicity (Ref. 8).
a. Renal toxicity. The oral reference dose (RfD) for ethylene
glycol as established by the Agency's RfD/RfC (reference concentration)
working group is 2 milligrams per kilogram per day (mg/kg/day). An RfD
reflects the Agency's estimate of a level of daily exposure to the
human population (including sensitive subgroups) that is likely to be
without an appreciable risk of deleterious effects during a lifetime
(Ref. 19). The RfD for ethylene glycol is based on a feeding study by
DePass et al. (1986, as cited in EPA's Integrated Risk Information
System (IRIS), 1994; Ref. 20) in which the critical effect was kidney
toxicity. Groups of male and female rats (30/sex/group) and male and
female mice (20/sex/group) were fed diets containing ethylene glycol at
doses of 0, 40, 200, or 1,000 mg/kg/day for 2 years. Urinary calcium
oxalate crystals and increased kidney weight were seen in all high-dose
rats. Histopathologic changes in high-dose male rats included tubular
cell hyperplasia, tubular dilation, peritubular nephritis, parathyroid
hyperplasia, and generalized soft tissue mineralization. No adverse
effects were seen in rats of either sex at the mid or the low doses.
There were no adverse effects seen in mice of either sex at any dose
tested. The Lowest Observed Adverse Effect Level (LOAEL) was determined
to be 1,000 mg/kg/day and the NOAEL was 200 mg/kg/day. The RfD was set
with an uncertainty factor of 100, 10 for interspecies extrapolation
and 10 for differences in human sensitivity. Confidence in the study,
the uncertainty factor and the RfD was high.
b. Developmental/reproductive toxicity. IRIS includes a review of
several developmental reproductive studies with LOAELs at or near that
seen in the DePass study which was
[[Page 24922]]
William Beaty wrote:
On Mon, 22 Jul 2002, Bernard Cleyet wrote:
Have you tried blowing out a candle or match? Also the collision of two
rings?
Also try shooting a fast ring after a slow ring so the second one catches
up.
The zerotoys site says that the fluid is glycerine & glycol
http://www.zerotoys.com/lowres/faq.html
(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com http://amasci.com
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