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Story by Jon Hunt
Drinking water containing infected organisms can rapidly lead to a backcountry survival scenario.
Last spring my hunting partner and I were reminded of this possibility midway through our long-awaited Southeast AK brown bear hunt. Experimenting with luxury, we decided to rent a cabin rather than camp. Actually, the thought of a dry shelter on a remote hunt was a refreshing concept, especially a cabin with a kerosene stove. The cabin website stated that fresh potable drinking water was available next to the cabin. The anticipated luxury was not what we experienced.
By the third day of our hunt, we discovered that our “drinking water” was piped in from a nearby stream, and not safe for consumption. Realizing we were at risk, we boiled all of our drinking water from that point forward.
The cabin heater didn’t work, leaving us with a large amount of kerosene at our disposal, which came in handy. I was able to field test my new MSR® WhisperLite™ Universal Stove (MSRP $139.95). Since TSA prohibits flying with canister fuel, I was hoping to buy some in the local village store, but none was available. This MSR® stove burns liquid fuel or canister fuel.
Luckily we were spared the wrath of a water-borne illness. However, the topic of treating water is a popular concern discussed with hunters in our Wilderness First Aid programs. The reality is, no one wants to hike in enough water to get them through a hunt. Many factors need to be analyzed before choosing your primary means of water treatment, and hopefully you have a backup plan.
There is significant confusion about how to ensure that drinking water is safe. It is obviously essential for survival. Without proper hydration, the body cannot maintain cellular functioning. There is an actual risk of dehydration, volume shock, and even death.
From an Alaskan backcountry perspective, we often have the luxury of accessibility to water. However, Is this water safe to drink? The water may need to be treated. There are numerous methods for water treatment, all of which have pros & cons. In my experience, there are conflicting information and opinions about the best method, or if water treatment is even necessary. Several factors complicate the situation, such as: water temperature, water clarity/suspended particles in the water, pH level of the water, allergies, thyroid problems, pregnancy, age, time available to treat the water, cost of your product to treat the water, size & weight of your treatment method, etc. The intent of this article is to evaluate some of the most common methods that hunters use for rendering water safe to drink. It is by no means comprehensive, but rather, a good starting point for further evaluation.
The three main categories of infectious organisms in water are:
Options for eliminating microorganisms in water:
HEAT:
Every source I have ever read, including the CDC & EPA suggests that boiling water is a reliable method for disinfecting water. The typical argument is over the duration of time that water should boil, rather than its effectiveness. Most sources agree that a rolling boil for 1 minute is adequate to kill all organisms at elevations less than 6500 feet; at higher elevations (I hope you are sheep hunting), boil for up to 3 minutes. The www.CDC.GOV reports that, “If boiling is not possible, a combination of filtration and chemical treatment is the most effective pathogen - reducing method.” Many organisms are destroyed before the water even reaches boiling point.
PRO’s – Most reliable and effective method; easy to do, no added chemicals or filters necessary.
CON’s – Inconvenient and time consuming; requires a heat source and container. Liquid fuel is expensive, heavy and not always available. Wood is not always dry or accessible.
WATER FILTRATION:
There are dozens of filter options on the market, ranging from gravity-fed to hand pump. MSR®, Katadyn® and Sawyer® appear to be the most popular brands. Pay attention to the “absolute pore size” of the filter, as some brand’s product descriptions are misleading. Most quality filters will remove organisms that are 0.2 microns, which does not filter viruses. Some manufacturers add chemical treatment to their filter. However, there are contradictory opinions about the effectiveness due to limited exposure time of the disinfecting chemical to the water. Also, pay special attention to manufacturer instructions on how to care for the filter when not in use.
The primary filter that we sell to hunters is the MSR® Hyperflow™ Microfilter (MSRP $99.95), which filters 3 liters per minute. Measuring 7” x 3.5”, it filters to 0.2 microns. Twenty strokes of the pump filters 1 liter by using a hollow fiber filter system. It is field maintainable.
Filters range in price, size, weight, flow rates, pore size, and level of difficulty to operate and maintain. I have used filter systems for years and have had no problems with them in the field.
PRO’s – Fast. Effective against parasites and bacteria.
CON’s – Relatively bulky and expensive, requires maintenance and cleaning; some filters are not durable; typically NOT effective against viruses.
CHEMICAL TREATMENT:
IODINE:
Available in several forms, including: tincture (liquid solution used in first aid), crystals, and tablets (most commonly sold in a glass vial of 50 tablets). Most tablets containing “Tetraglycine Hydroperiodide,” i.e. Portable Agua® (MSRP $11 when sold with the vial of taste-neutralizing tablets). Two tablets treat one liter of water.
PRO’s: Easy, inexpensive, fast acting (30 minutes).
CON’s: NOT effective against Crypto. HIGHLY effective against viruses and bacteria. Shelf-life diminishes once the tablets are exposed to air, heat, humidity, moisture and light. Possible hazard to: people with hypersensitivity to iodine, allergy to shellfish, thyroid problems, pregnant, young, or elderly. Not recommended for use beyond a 2-week period. The iodine taste is noticeable. If flavoring is added to improve the taste, wait till the water is completely treated. In cold water, the iodine requires longer contact time.
CHLORINE:
Chlorine is NOT effective against Crypto. It has only a low-moderate effectiveness against Giardia. It is HIGHLY effective against bacteria and viruses. The effectiveness of chlorine is pH sensitive; free chlorine levels need to be monitored. In a wilderness setting, chlorine as a disinfectant has questionable reliability.
CHLORINE DIOXIDE:
This is a reliable method of water treatment proven effective for decades. Potable Aqua® (MSRP $9.95) is available in 20-tablet packages that are convenient for use in the backcountry. Each individual tablets is sealed in foil and treats 1 liter per tablet.
PRO’s: Effective over a wide variety of pH ranges; biodegradable, no aftertaste. Effective against a broad variety of organisms.
CON’s: 4-hour treatment time required for complete effectiveness.
ALTERNATIVE METHODS OF WATER TREATMENT:
EMERGENCY DRINKING STRAW:
Several manufactures produce what I consider an emergency drinking straw that enables you to drink water directly from a stream, or to fill a bottle and then drink through the straw. I don’t like this as a primary water treatment method because I don’t want to use a straw as my sole means of hydration. It is a great concept for an emergency. The LifeStraw® (MSRP $21.95) filters 1000 liters to 0.2 microns, thus removing bacteria and protozoa (Giardia & Crypto).
PRO’s: No waiting, chemicals, batteries, or pumping. Filters a high volume of water before the product clogs. Multiple product options are available that adapt to a bottle or larger family unit with a pump. EFFECTIVE against a broad range of organisms. Relatively lightweight (2 oz), compact (1.2” x 8.8”).
CON’s: All compact options for water treatment need to be sucked through the straw while in the field. NOT effective against viruses.
ULTRAVIOLET LIGHT:
Most commonly sold as the SteriPEN™; multiple options are available, but the Adventurer model (MSRP $89.95) is the most compact version and comes with a protective case. Several products on the market use ultraviolet light to kill organisms. I’m personally not a fan -- I hate the thought of having to rely on a battery. However, the concept is tempting, due to the large spectrum of organisms that it is proven to eliminate – including viruses, bacteria, and protozoa (Giardia & Crypto).
PRO’s: Very fast acting (1 liter of clear water in 90 seconds). Relatively small and lightweight (6.1” x. 1.5” x 1”; 3.6 oz with batteries). Does not affect taste of the water. No chemicals, no allergy concerns. Effective against a broad spectrum of organisms. The Adventurer model doubles as a flashlight.
CON’s: Battery-dependent. Relatively fragile, 2” glass bulb is exposed when in use. Water needs to be clear for effective treatment.
In summary:
Plan ahead to have a safe method to treat water in the backcountry. Do not forget to have a backup plan. Boiling water is the most reliable option for treatment; pro’s and con’s are present with every method so carefully choose what is best for your next hunt. The CDC reports that, “Cryptosporidium is the leading cause of waterborne illness in the U.S. The germ is found in every part of the world and U.S.” Don’t underestimate the frequency of illness due to organisms in the water – even if the water looks beautiful and is flowing!
Safe Hunting!
This table demonstrates the effectiveness of each water treatment method with regard to the organisms.
|
Crypto 4.0 microns |
Giardia 6.0 microns |
Bacteria 1.5 to 3.0 microns |
Virus 0.004 to 0.06 microns | |
|
Chlorine |
Not Reliable |
Not Reliable |
Not Reliable |
Not Reliable |
|
Potable Aqua® Iodine Tablets |
Not Effective |
Effective |
Effective |
Effective |
|
Potable Aqua® Chlorine Dioxide Tablets |
Effective |
Effective |
Effective |
Effective |
|
Boiling |
Effective |
Effective |
Effective |
Effective |
|
MSR® Hyperflow™ Filter |
Effective |
Effective |
Effective |
Not Effective |
|
Filter & Chlorine Dioxide |
Effective |
Effective |
Effective |
Effective |
|
SteriPEN™ Adventurer |
Effective |
Effective |
Effective |
Effective |
| LifeStraw® |
Effective |
Effective |
Effective |
Not Effective |
Sources used in this article include:
*Wilkerson, James A., Medicine for Mountaineering, 6th edition, 2010.
*Product specifications were obtained from the manufacturer: