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Re: [pct-l] Giardiasis, filtering water



Why do I wait one whole hour for the Iodine to disinfect.  Mainly because I
am super conservative about this having had giardiasis.  Being sick in the
Mountains seems to be much worse than in town, it ruins your trip like
nothing else. Major Bummer.

But also I have read the literature on temperatures and rates of
disinfection, and other things that affect these rates

If the water is not 68 F , and most of the mountain water that I run into
is much colder than that, then the time for disinfection goes up markedly.
Also the Satuuration of the Iodine solution varies by temperature. I have
never had time to heat water to raise the temperature of the water I am
trying to disinfect.

In the desert and Canyons (can also have very cold water), I find that the
major problem is turbidity and minerals.  This also affects amount of
iodine needed and rate of disinfection.

Lastly, What I remember is that they were talking percentages: you find
that most of the bad stuff dies in 20 minutes( but not all of it?)  Giardia
cysts take the longest.  It has been a while since I read this stuff.  But
I clearly remember going down to the "bottomline",and it was an hour.  This
has worked for me. But then, I like to let the iodine work overnight too. 
Sigh! <G>   Will I ever loosen up?

Sincerely
Goforth

----------
> From: Bill Deutschman <olcbill@cdsnet.net>
> To: pct-mailing list <PCT-L@backcountry.net>
> Subject: Re: [pct-l] Giardiasis, filtering water
> Date: Monday, January 18, 1999 5:30 PM
> 
> >>Waiting a hour for the iodine to disinfect
> >>can be hard when you're really thirsty.
> >>
> >
> >I was under the impression that iodine tabs take 10 minutes to be
> effective,
> >but I'm sure someone will differ in opinion.  Also, I have heard that
> iodine
> >taken over a long period of time does irreversible damage to ones liver.
> 
> I'm not an expert Chemist but my bottle of Polar Pure says: "Let stand 20
> minutes before use.  ....  To destroy Giardia cysts, drinking water must
be
> 20 degrees C ( 68F) minimum.  (water can be warmed in sun, or add hot
water
> to cold)."
> 
> I use an MSR filter and have never had Giardia or dysentery, but I also
put
> garlic cloves around my garden to repel elephants and I have never had an
> elephant in my garden either.  Unfortunately it doesn't keep the deer
out.
> :')  When I am in areas where the water is really bad I treat it with
> Iodine, wait 20+ minutes and then filter it.
> 
> bill
> 
> Bill Deutschman, Ph.D.
> Oregon Laser Consultants
> 455 Hillside Avenue
> Klamath Falls, OR 97601-2337
> olcbill@cdsnet.net
> 
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