Some very good information on the Mountain Equipment Co-op site, and also the REI site.
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</A>

http://www.rei.com/reihtml/LEARN_SHA...atertreatf.jsp


Here's the bottom line:

"To fully disinfect suspect water using a water filter, the Centers for Disease Control and Prevention recommends 1) mechanically filtering the water, 2) treating it with a halogen (chlorine or an iodine solution), 3) letting it sit 15 to 60 minutes, 4) then drinking.

Per REI, "A water 'filter' removes bacteria (e.g., Campylobacter jejuni) and protozoan cysts (Giardia lamblia, cryptosporidium) from contaminated water.

A water 'purifier' removes bacteria, protozoan cysts AND viruses (infinitesimal organisms too tiny to be trapped by a filter, e.g., hepatitis A) from contaminated water.

Devices identified as "purifiers" usually cause water to interact with iodine (often in the form of iodine resins), which can render viruses inactive.

Another purifier uses a positive electrostatic charge in its filter medium to capture viruses."

So the good news is that there is a non-chemical alternative - the First Need Deluxe Water Purifier: "The Deluxe is the only non-chemical water purifier certified to EPA Guide Standard for microbiological purifiers against bacteria, cysts and viruses. It also removes unpleasant tastes and certain chemicals."

Susan

[This message has been edited by Susan (edited 15 February 2002).]

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Susan Johnson

Inspiring, Informing and Connecting travellers since 1997
www.HorizonsUnlimited.com