Water Purification Update

February-March 2002

This is an article from WaveLength Magazine, available in print in North America and globally on the web.
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by Paul Nicolazzo

As wilderness users, we all know that surface water carries the possibility of disease. And we know the solution is to purify our water prior to use. Yet, there is often a lot of confusion and fireside debate surrounding the question "How should I treat my water?" Hopefully this article will enable you to choose a water purification system that meets your needs. In addition to the standard methods of water purification (boiling, filtration, & halogens) I have included review of Grapefruit Seed Extract (GSE).

According to the Wilderness Medical Society the most common waterborne pathogens in North America are the protozoans Giardia lamblia & Cryptosporidium and the bacteria Campylobacter jejuni and E. coli. In developing countries the list also includes the protozoan Entamoeba histolytica, the bacteria Shigella, Vibrio cholerae, Salmonella, and V. parahaemolyticus, and the hepatitis A virus. In addition to those listed above there are potentially many more; these are simply the most common. Certainly the form of purification you choose should at the very least kill these common organisms. It would be nice if it were so simple. Unfortunately each method described below has its advantages and disadvantages. The method you choose should take these into account.

Prior to purification (if the water is NOT clear) it makes sense to remove any suspended particulate and organic matter; this improves the effectiveness of your chosen purification method and often the taste. The low tech method is to let the water stand for at least one hour and then remove the clear surface water without disturbing the sediment by dipping or pouring through a coffee filter. A faster method and one that removes material that will not settle with simple gravity, is to add 1/8 to 1/4 tsp/gal of alum (aluminum sulfate), mix thoroughly, and then wait for five minutes, stirring occasionally. When the floc has settled, decant the clear water from the surface. Alum can be found in the spice section of most standard grocery stores (alum is also known as pickling powder). Lime and fine campfire ash may used if alum is not available. Charcoal filters also clarify water but often clog quickly if the water is extremely cloudy. While charcoal filters, like the methods listed above, improve the taste and clarity of the water, they should not be considered a purification method by themselves.

BOILING

It has long been accepted that boiling water for 10 minutes (adding a minute for each 1000 feet above sea level) renders the water sterile. This is true; however, bringing water to 160 F for 30 minutes will kill all infectious organisms, and increasing th temperature slightly, to 185 F, will kill them faster, within a few minutes. Since the temperature of boiled water (even at altitude) exceeds 185 F and the time necessary for to bring it to a boil (even at altitude) exceeds a few minutes, water brought to a boil is safe. Since taste comes from both the oxygen and mineral content of the water, the flat taste of boiled water may be improved by pouring it from container to container for a few minutes.

Clearly the advantages of this method are its effectiveness. The disadvantages are the availability of fuel and the amount of time required to bring the water to a boil.

FILTERS

Filters are effective against protozoans, bacteria, and parasites, if their pore size is small enough ( Giardia and amoeba cysts: 5 microns, most enteric bacteria: .2-.5 microns, Cryptosporidium: less than 3 microns, and general parasite eggs and larvae: 20-30 microns). Filters that use an iodine resin may give some protection against viruses; however, because contact time is short they are not completely reliable. The advantage to filters is their high speed and reasonably good taste. The major disadvantage is that they do not offer reliable protection against viruses.

HALOGENS-IODINE & CHLORINE

Iodine and chlorine are effective against viruses, bacteria, and protozoans except Cryptosporidium cysts. Both are available in tablet or liquid form; iodine is also available as crystals or resin.

Since iodine is physiologically active, pregnant women, persons taking lithium, and those with a known iodine allergy or with an active thyroid problem should not use it. In addition iodine use should be limited to months of continued use rather than years.

Since contact with organic material renders both halogens inactive, pre-filtering (clarification) is required if the water is cloudy (see above). The effectiveness of halogens depends on three criteria: the temperature of the water, the concentration of the halogen, and the contact time. Since micro-organisms increase their activity as the temperature rises, contact time is shorter with warm water and longer with cold water; it takes much longer to kill Giardia cysts in very cold water. The chart on the next page shows the relationship between concentration, contact time, and temperature for both iodine and chlorine.

The advantages to halogens lie in their size (easy to carry) and speed. Poor taste, a major disadvantage to both iodine and chlo- rine especially at high concentrations, can be eliminated by adding a small amount of powdered ascorbic acid (vitamin C) to the water after it has been treated. Medically, the most significant disadvantages are that both iodine and chlorine are NOT effective against Cryptosporidium cysts. And remember that iodine should be used with caution since it is physiologically active (see italics above).

GRAPEFRUIT SEED EXTRACT (GSE)

While not yet recognized by the Wilderness Medical Society, the use of Grapefruit Seed Extract (GSE) is gaining popularity as a water purification treatment. Lab tests indicate that GSE is effective against a wide range of pathogens, including viruses. Many medical practitioners have successfully used GSE to treat bacterial, protozoan, fungal, and viral infections. While the Federal Drug Administration (FDA) researchers and the World Health Organization (WHO) do not yet recommend GSE as a water purification method, they do endorse as a safe and effective treatment for numerous conditions (equal or superior to conventional anti-microbials). Manufacturers of GSE recommend it for treating water and back up their statements with in vitro (lab) tests and testimonials. As a water treatment GSE is very attractive because it is fast, easy to carry and use, may be used as a treatment for a variety of infections and conditions (eg: prevents Traveler's Diarrhea), has no side effects, is safe for long term use, and is inexpensive. Its only apparent disadvantage is its bitter taste and acidity (a possible problem for those with pre-existing acidic problems).

GSE is made from organic grapefruit seeds, pulp, and white membranes (details about the process and the type of active compounds are readily available in the literature). In concentrated form it is highly acidic and unsuitable for human consumption; however, when diluted with vegetable glycerine or water it is a highly effective antimicrobial. Research indicates that GSE appears to disrupt the cytoplasmic membrane in such a way that the organism is unable to uptake necessary amino acids. GSE also causes minor leakage of cellular contents and inhibits cellular respiration -all not good for the invading organism. can affect a wide variety of pathogens without adverse affect on animal life. Nor do they know how GSE affects viruses since viruses do not have a cell membrane of their own. But they do know that it is effective against an overwhelming number of pathogens.

GSE is available as a liquid or powder from numerous manufacturers. Although the powder is tasteless (liquid GSE is bitter), liquid GSE is more suitable for water purification since it is easier to vary the dose according to need and dissolves more quickly in water. Because the concentration of GSE products vary according to the manufacturer, you should follow the directions included with the product you buy. Note that water-based (versus glycerine based) GSE dissolves faster, thus decreasing the contact time. The recommended dosage for Traveler's Friend (a water based GSE product made and distributed by NutriBiotic) is 3-5 gtts (drops) per glass or 20-30 gtts per gallon; contact time is ten minutes. Consider extending the contact time to 20 or 30 minutes if the water is cold. Liquid GSE is available at most health food stores and from our website (www.Wild MedCenter.com).

After all this, what purification method should you use? Well, it depends primarily on your personal preference and use. If fuel is readily available you might choose boiling, especially if you have the means to safely store and carry the treated water. Clearly boiling is the treatment of choice when you are heating water for meal preparation or drinks. Filters work well at altitude or in snow country where the chance of viral infection is minimal and Giardia may be present (as in snow melt or old snow; fresh snow is usually safe). Halogens work well if you are able to use them and there is no risk of Cryptosporidium. GSE is a great alternative if you can handle the bitter taste and the lack of definitive research. Most people use a combination of methods depending on how and where they are traveling. I have successfully used all of the above methods during my outdoor career. These days I tend to rely on boiling water when in camp and GSE while traveling. Remember to clarify all cloudy water before purification.

REFERENCES

Forgey, William W.: Practice Guidelines for Wilderness Emergency Care, second edition, Wilderness Medical Society, Guilford, The Globe Pequot Press, c2001.

Sachs, Allan: The Authoritative Guide to Grapefruit Seed Extract, Mendocino, LifeRhythm, 1997.

Sims, Judith: Grapefruit Seed Extract, Gale Encyclopedia of Alternative Medicine, Gale Group, c2001.

GSE Report, Vol. 1, Issue 1, Novato, Praxus Inc.

Citricidal, Lakeport, BioChem Research Inc.

© Paul Nicolazzo is Director of the Wilderness Medicine, Training Institute, Winthrop WA. (www.Wild MedCenter.com). WMTC specializes in practical instruction in wilderness medicine and offers a variety of specialized gear for remote conditions.