toxicity chrome alum?
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- Date: Wed, 02 Sep 2009 22:08:54 +0200
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i just mixed up a 10% stock solution for sizing (used 0.2-0,3 gr/ 100ml
5% gelatin) and with the recent safety discussion, it's probably a good
time to bump this question.
usually there are one or two chemists on the list. maybe can provide a
final answer to the question below. and if there are any extra risks
involved in handling the stuff (while taking the usual safety
precautions like with every other darkroom chemicals: gloves, avoiding
the use of powder/ breathing in, cleaning ... etc)
i assume that chrome alum has an unnecessary bad reputation (aka being
as toxic as the dichromates). but i'd rather be safe than sorry.
phritz phantom schrieb:
Judy Seigel schrieb:
i saw this mentioned before, among others by sandy king. when i first
ordered the chemical, i looked around, if there was any info available
on the toxicity, precautions when handling... etc. but there wasn't
much info available. to my understanding (from what i was able to find
out), chrome alum is a chrome (III)-compound, which are not as toxic
as chrome (IV)-compounds (such as the dichromates). there aren't any
hazards mentioned on the english and german wikipedia pages. but i
don't know, if there really aren't any, or if just nobody added them yet.
As for chrome alum & company, it's my understanding that they are
quite poisonous, and remain so, and not what you want to drop into
the water table (along with all those hormones and pthylates).
Whether glyoxal is poisonous or not, it does break down (as I
understand these matters, but admit that I am not a chemist), and
certainly by the time I dispose of it seems entirely attenuated.
effects on the water table could maybe be neglected, since most of it
should stay on the paper (within the gelatin size) anyway.
but maybe someone more chemistry-literate than me could shed some
light on the whole thing.