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Re: Purifying Water
-- [ From: Joe O'Neill * EMC.Ver #2.10P ] --
> Do water purification tablets work as effectively as a filter system
> (such as Sweetwater)?
> I can see myself filling up my water bottle mid day and dropping a
> tablets in it and then continue walking while the stuff purifies - it
> seems faster than a filter and I can save the use of the filter (and
> life of the cartridge) for at camp...Is this a common practice and/or
> good idea as far as having healthy water goes?
Thought you might be interested in a query/response I found on a
Subject: WATER PURIFICATION
From: BRUCE AKERS (SEPG34A)
Time: 01/20 10:16 PM
I recently saw a program, Popular Mechanics, a weekly show.
They interviewed an AT thru hiker about his experience and
the equipment that he used. When asked about water
purification he pulled out a bandana and a bottle with a
medicine dropper containing clorine. He indicated to the
show's host that that is what he used for his entire trip.
I was wondering how effective his simple treatment system
would really be. I'm no chemist and was wondering if his
system really was safe and effective.
PRODIGY(R) interactive personal service - Date: 02/14 Time: 7:53
Subject: WATER PURIFICATION
To: BRUCE AKERS (SEPG34A)
From: KARL PENNY (WERP08A)
Time: 02/12 11:37 PM
Hi, Bruce: Chlorine works, up to a point. That is, what
it does kill, it kills quickly and effectively. It's what
it doesn't kill---most notably Giardia---that is worrisome.
Iodine kills a wider variety of microorganisms than
chlorine, and is therefore more widely recommended and used.
However, iodine has its problems. The lower the temperature
and oxygen content of the water, the greater the dosages and
standing times before drinking are required. Where
available water is primarily composed of snowmelt (only a
few degrees above freezing), it is recommended that you
double both the dosage and standing time. In practical
terms, this means that, among other factors, you'll have a
wait of anywhere from a half-hour to an hour before being
able to drink the treated water.
Neither chlorine or iodine does anything about
particulate matter in the water (silt, algae, etc.), hence
the bandana. Drinking said particulates is usually more
unpleasant than it is dangerous, but I suspect most of us
would not willingly consume them, given any choice in the
Iodine can accumulate in the body (notably the thyroid)
and cause problems---yellowing of the skin being the least
of them. Generally speaking, it is not recommended that one
rely upon iodine for water purification for more than a week
and a half (two weeks, according to some, more generous,
estimates). Planning a thru-hike of the AT in that period
of time might be most charitably described as unrealistic.
<G> People with thyroid problems, and pregnant women, are
advised to steer clear of iodine altogether.
Secondary treatment of iodine, such as is available
with Potable Aqua, will neutralize the iodine and kill its
unpleasant taste, which helps offset some of the above
objections. On the other hand it involves one more extra
step and another bottle of tablets to keep track of. The
secondary treatment, BTW, is nothing more exotic than citric
acid, or good old vitamin C. >>>MORE>>>>
Mechanical purifiers, such as the Pur Explorer and
Scout models, which use a iodine system do leave trace
amounts of iodine in the water, and carry the appropriate
cautions in their instruction manuals. Most such models,
however, do offer an optional carbon cartridge which can be
attached over the outlet to neutralize the iodine. At a
greater cost in weight, bulk, and price, of course. Iodine,
BTW, is the only treatment that will protect against
viruses, which is something to consider when Third World
travel is on the agenda.
Hope this helps. Happy trails.
N & N, Karl
PRODIGY(R) interactive personal service - Date: 02/14 Time: 7:54 AM