Posted on 01/22/2007 6:57:43 AM PST by Red Badger
And you still don't get it. Did you not see the exposure limits in thec MSDS I posted? They are in the 50-100 ppm range, depending on the agency and country. So now I know why you didn't like posting the MSDS - it had some exposure restrictions on it.
Don't be a moron, moron. I read the MSDS and saw the exposure levels. So what?? Are you worried about acute exposure or chronic exposure?? There is already industrial toxicology data available for acute exposure, which is what a 50-100ppm exposure would be. The "environmentally scary" exposures are the chronic, long-term, low-level ones. And those supposed chronic, long-term, low-level exposures are belied by the already-existing evidence for a wide range of exposures to/from natural sources.
I think YOU're the one who doesn't "get it".
Neato. One question, though: are these microorganisms robust enough to survive in the wild?
The difference is that n-butanol can be biologically degraded. It oxidizes in vivo, for example, into butanoic acid, which is what makes rancid butter stink. Butanoic acid can be degraded along the usual lipid-metabolism pathways. That doesn't mean you want to drink it, but it does mean that soil bacteria can detoxify it, at least in small amounts.
Of course n-butanol has acute toxicity at sufficiently high dosages, but so does everything else. (Water and ethanol included.)
MTBE, OTOH, is strictly a synthetic, with no relationship to anything biological. It's not going to biodegrade readily, because there are no natural enzymes with any capacity to bind to it. So it sits around. Stuff that sits around like that is typically carcinogenic. Benzene is the same sort of thing; enzymes generally don't know what to do with it, so it sits around.
So you don't think that widespread use may have unintended consequences? You are certain of that? My only point is not that this stuff is particularly nasty, nor that it is totally alien to the environment, but that some work should be done to establish its environmental fate if leached into ground water, mainly because if this stuff can be produced in large enough quantities for extensive, if not ubiquitous, fuel use, it will be present at %wt levels, well above the ppm limit values and the ppb natural background levels in the environment, and could contaminate well water people drink from. So to answer your question, I'm worriedc about chronic levels above the acute exposure limits. The MSDS is, to me, enough to warrant cautious initial steps. It is better to take safety into conideration at the beginning of an endeavor and find no problem than to try to fix it after the fact. But it seems you would just run wild with it and damn the consequences. I think our biggest difference on this is how much the exposure would be and its effects. I believe it could be much higher than you do. Buy that's why research into the rate of leaching vs the rate biodegradation (for example) are important as well as the effects of chronic exposure above the background limits you have described here.
Thanks for the info. Like I said in my previous postings, I'm worried about how much will be in the environment if n-butanol becomes a popular fuel. Will it make it into groundwater bufore it is decomposed. Will people have stinky well water from trace butyric acid? You don't need much of that to be nosed. If, and that is a big if, it does get that far, people will complain about it and that's where the politicians and lawyers get involved. Would a ground contamination threshold be established?
I dunno. But let's hope we don't let them loose, or we'll be up to our butts in butt-anol!..........
And you are wrong. The appropriate test model is MTBE. The vast majority of MTBE groundwater samples are less than 20 ppb, and this is with a compound that is NOT easily biodegraded.
Butanol will have a similar distribution, and IS easily biodegraded, so the exposure levels will be less than 20 ppb--which level is less than the natural levels people are already exposed to.
The whole MTBE whoo-hah is sheer eco-freak and media induced panic exactly like the "Alar scare". The ONLY real problem with MTBE is that it can impart an odor to water---it is NOT toxicity.
"But that's why research into the rate of leaching vs the rate biodegradation (for example) are important as well as the effects of chronic exposure above the background limits you have described here.
But that research HAS ALREADY BEEN DONE, and a synopsis can be found at the EPA website.
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