AMC Outdoors, May 2006
For years, hikers only had three real options when it came to treating water in the backcountry: boil it, filter it, or add iodine. Now a broad array of weaponry is available to exterminate all the aquatic baddies looking to take up residence in your gut: bacteria, viruses, cryptosporidia, and especially parasitic enemy number one, giardia cysts.
ZAP ’EM A beam of ultraviolet light kills viruses, bacteria, giardia, and cryptosporidia in a matter of minutes. Now you can zap your water in the backcountry with compact UV lights such as the eight-ounce SteriPEN from Hydro-Photon ($149) or the seven-ounce AquaStar Deluxe from Meridian Design ($99), which is integrated with a screw cap that attaches directly to the top of a wide-mouth Nalgene bottle.
Pros: Fast, no flavor, kills viruses
Cons: Expensive, bulb durability concerns, battery-powered
FREE THE RADICALS Chlorine dioxide is a gas that kills everything, including viruses and cryptosporidia, with enough time (20-30 minutes for giardia, 4 hours for crypto). It is readily produced from tablets, such as those available from Potable Aqua and Katadyn, which chemically react with water ($10-$13 to treat 20-30 liters). Another option is McNett’s Aquamira, a two-solution system that requires mixing in the field to activate the gas, but treats up to 120 liters ($12).
Pros: Kills everything, simple, inexpensive, little to no flavor
Cons: Undissolved tablets and drops extremely toxic
ELECTRIFY BRINE By sending an electrical charge through salty water, you create a mix of oxidants that is lethal to all your micro-nemeses. This is the technology behind the 3.5-ounce MIOX from MSR ($130), which uses rock salt and a small battery-powered current to produce the potent cocktail. Giardia and viruses are extirpated within 30 minutes, crypto in 4 hours. The U.S. Army recently ordered thousands of MIOX to supply troops overseas in Iraq and Afghanistan.
Pros: Little to no flavor, can treat large volumes of water
Cons: Expensive, requires disposable “testing strips”
STRAIN ’EM Filters work by forcing water through extremely small openings in a porous membrane, usually accomplished using a hand pump. Typically 0.2-0.3 microns in size, these holes are too small for bacteria and crypto and giardia cysts to pass through, though viruses still get by. A variety of different filter materials are available, but often the most important feature is the ergonomics of the pumping mechanism. Choose whichever feels most natural to operate.
Pros: No taste, removes sediment, tried-and-true technique
Cons: Bulky, lots of squatting, expensive filter replacements
PURIFY Unlike filters, purifiers also eliminate viruses. While this is not really a concern in the North American backcountry, it can be in third-world countries where sanitation is questionable. The all-time standby is the First Need Deluxe Purifier ($95), a pump which has existed virtually unchanged for more than two decades and removes viruses through an electrostatic attraction. Note that some filters sold as purifiers only eliminate viruses through a second-stage chemical treatment-a two-step process.
Pros and Cons: See filters above
USE IODINE Iodine kills everything but crypto in 20-30 minutes and has been the standby chemical method for decades. Potable Aqua tablets are readily available ($6 for 50 tablets, good for 25 liters), but you can treat 40 times more water with Polar Pure ($11), which uses iodine crystals to saturate a small amount of water that you then add to your bottle. Iodine imparts a noticeable-and to some, disagreeable-taste and odor to the water. There are no proven long-term effects of using iodine for extended periods of time, though health experts still advise against it.
PROS: Cheap, lightweight, easy to use
CONS: Bad taste, crypto will still get you
BOIL AWAY Heating water to the boiling point kills everything. Recommendations vary on how long you need to boil it, though 2-3 minutes is the standard advice. You’ll need a lot of fuel and time, though, to treat much water.
Pros: No taste, no pump, no chemicals
Cons: Pounding scalding water is difficult
-Matt Heid is Senior Editor at AMC Outdoors.
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