Scouts-L Mail Archive for October of 1998: Re-post of water purifier comment
Re-post of water purifier comment
Wed, 28 Oct 1998 16:03:06 -0500
Here is a re-posting of the comments I made this morning about iodine vs
filters and purifiers. The original post was sent using MIME and I found
out that that does not work very well! Sorry for the double post.
I've been following the discussion on the advantages of using iodine to
treat water vs. the use of filters/purifiers...
One point AGAINST using just iodine (either tablets or the liquid) is that
some protozoa "critters," most notably cryptosporidium, are resistant to
chemical treatment (due to the hard "shell" that forms their body).
Chemicals can have a tough time penetrating their shells to kill them. The
good news is that Protozoa are really big compared to the size of viruses
and that makes them easy to filter out of the water. Chemical treatment is
most effective against the smaller bacteria and much smaller viruses (even
the best "filters" can not trap viruses).
For the best protection, you can not rely on just iodine/chemical treatment
OR filtering. You must combine both to get the "purifiers" that are
currently on the market -- a filter having a small pore size followed by an
"integrated" iodine treatment -- or go back to boiling.
The common remark that "I have been using method XX for years and nothing
bad has happened" is short sighted. Some Appalachian Trail through hikers
have remarked that they stopped treating their water and never got sick.
That kind of logic would seem to say I can skip treating the water since I
live over here in VA near the AT!!!! There was a time in our country where
water generally did not need to be treated at all!
I use purifiers whenever possible in order to minimize the risk to my
health or that of my scouts on methods that are known not to be effective
on all 3 critters -- protozoa, bacteria, and viruses! Maybe I fall on the
"overkill" side, but I like to think of it as the "be prepared" side.
A very good overview of water contamination and treatment methods can be
found on the REI web page under their "advice" section.
SM, Troop 56