Ok I am confused here then. I respect your credentials of course and the fact you do this for a living. I am not challenging your credibility, but looking for a more defined explanation from the two experts.
On the surface if you are an dummy like me and most others when we Google ethyelene glycol there are huge amounts of information about its potential toxicity which appears to be the byproducts that are produced when ingested. I understand that in normal diluted quantities found in nature that it probably doesnt present a problem. My understanding also is that the EG is a sweet substance which if an animal...say a dog, squirrel, racoon, bird got a hold of it they would continue to ingest it because of its attractive scent as well as tatse and that what made it dangerous. The PG is sour and doesnt have the same properties or by products when ingested.
So is this incorrect and all this huge amount of online info incorrect also? Or is it in the quantities or concentrations we use the EG is not a toxic entity, but in greater concentration or ingestion it still could be.
Help me sort this out here.
http://en.wikipedia.org/wiki/Ethylene_glycol
Ethylene glycol (
IUPAC name: ethane-1,2-diol) is an
organic compound widely used as an
automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid. Ethylene glycol is toxic, and ingestion can result in death.
Toxicity
Main article:
ethylene glycol poisoning
Ethylene glycol is moderately toxic with an oral
LDLO = 786 mg/kg for humans.
[6] The major danger is due to its sweet taste. Because of that, children and animals are more inclined to consume large quantities of it than of other poisons. Upon ingestion, ethylene glycol is oxidized to
glycolic acid which is, in turn, oxidized to
oxalic acid, which is toxic. It and its toxic byproducts first affect the
central nervous system, then the heart, and finally the kidneys. Ingestion of sufficient amounts can be fatal if untreated.
[7]
According to the annual report of the American Association of Poison Control Centers' National Poison Data System in 2007, there were about 1000 total cases resulting in 16 deaths. The 2008 American Association of Poison Control Centers' National Poison Data System annual report lists 7 deaths.
(Toxicity, Ethylene Glycol)
Antifreeze products for automotive use containing
propylene glycol in place of ethylene glycol are available, and are generally considered safer to use, as it possesses an unpleasant taste in contrast to the perceived "sweet" taste of toxic ethylene glycol-based coolants, and only produces
lactic acid in an animal's body, as their muscles do when exercised.
[8]
From the CDC
http://www.atsdr.cdc.gov/csem/csem.asp?csem=12&po=0
Ethylene glycol ingestion first affects the central nervous system (CNS). After a characteristic latent period, signs of inebriation may be followed by serious illness and even death, caused by toxic metabolites.
Propylene glycol, which is much less toxic than ethylene glycol, is metabolized to compounds that are normal constituents of the citric acid cycle.
No health effects have been reported in persons chronically exposed to ethylene glycol or propylene glycol at levels found in the environment
