Dehydration is a common backcountry problem that affects children and adults alike. It can lead to fatigue, headaches, lethargy, irritability, and more serious injuries if left untreated. Your first line of defense is to keep your group hydrated by drinking plenty of water. For extended trips you may not always be able to bring enough water for the group and you will need to find additional sources in the backcountry. Staying hydrated on the trail is a high priority, but drinking water from backcountry sources carries some risks of its own.
Although there is some debate about the extent of microbiological contamination of backcountry water sources, it is generally accepted that the days when you could simply dip your water bottle into the stream for a cool refreshing drink without any risk of illness are gone.
Purifying water isn't difficult and you're better off being safe than sorry. Here are four basic strategies for purifying drinking water on the trail.
Boiling Drinking Water in the Backcountry
Boiling drinking water before use is the most reliable method of backcountry water treatment. Unfortunately, it requires a lot of fuel and can be extremely time consuming.
When hiking and backpacking we always carry matches and aluminum foil. If you find yourself in a position where you don't have alternative methods of water purification, the foil can be folded into a bowl and placed over a small fire. As long as you don't boil all of the water off, the foil will not burn and can be re-used multiple times. It takes a little practice, but many people have used this method when other options of water purification were not available.
Bringing the water to a rolling boil for one minute will kill all common waterborne pathogens.
Chemical Disinfection of Drinking Water in the Backcountry
Chemical disinfection of water in the backcountry is usually accomplished through the use of chlorine or iodine products. These types of products are inexpensive and can be found in most sporting goods stores.
The effectiveness of chlorine products will vary with the pH, temperature, and turbidity of the water that you intend to purify and therefore can produce varying results. Follow the manufacturer's instructions carefully and note that the product may be less effective after long term storage or use at high/low temperatures.
Iodine products tend to be less sensitive to pH, but do not reliably kill Cryptosporidium. Again, follow the manufacturer's instructions closely for best results. It is recommended that iodine purification of water be used only periodically, and not as a long-term disinfectant solution. If you or a member of your family has a thyroid problem, are taking lithium, are allergic to shellfish, or are pregnant you should consult a physician prior to using iodine for water purification.
Whether you are using a chlorine or iodine based treatment process, be sure to follow the manufacturer's instructions.
Filtration of Drinking Water in the Backcountry
Filtration of drinking water in the backcountry is a well established method of removing pathogenic microorganisms by "trapping them" with physical barriers.
There are essentially two types of filtration strategies used in commercial backcountry water filters: Membrane filtration and depth filtration. Membrane filtration occurs when thin sheets of porous material "strain" contaminants as the water passes through. Because membrane filters tend to trap particles on a membrane surface, they tend to clog easier.
On the other hand, a depth filter will only capture some of the particles on the surface. Depth filters have multiple layers of material configured in a matrix that capture particles throughout.
When purchasing a backcountry water filter, it is also important to note that there is a difference between a water filter and water purifier. Water filters alone will not protect you from viral contaminants. However, a good water purifier will filter protozoa and bacteria and will also inactivate virus through a secondary mechanism (usually through exposure to an iodine compound).
Pay close attention to the labeling and claims made by the manufacturer. According to the CDC:
"filters that are designed to remove Cryptosporidium and Giardia carry one of the four messages below-verbatim-on the package label.
- Reverse osmosis
- Absolute pore size of ≤1 micron
- Tested and certified by NSF International (formerly the National Sanitation Foundation) Standard 53 or NSF Standard 58 for cyst removal
- Tested and certified by NSF Standard 53 or NSF Standard 58 for cyst reduction
Filters may not be designed to remove Cryptosporidium and Giardia if they are labeled only with these words:
- Nominal pore size of ≤1 micron
- One-micron filter
- Effective against Giardia
- Effective against parasites
- Carbon filter
- Water purifier
- Environmental Protection Agency (EPA)-approved (Caution: EPA does not approve or test filters.)
- EPA-registered (Caution: EPA does not register filters for Cryptosporidium removal)
- Activated carbon
- Removes chlorine
- Ultraviolet light
- Pentiodide resins
- Water softener "
Source: http://wwwn.cdc.gov/travel/yellowBookCh2-FoodWaterRisks.aspx#Drinking
UV Sanitization of Drinking Water in the Backcountry
There is a relative newcomer to the backcountry water purification family. Previously, the only options available to the backcountry traveler were boiling, chemical disinfection, or filtration, but now we can add ultraviolet sanitization as a strategy.
For about $100, you can purchase a steriPEN. The manufacturer of steriPEN, Hydro-photon inc. claims that their product "purifies clear water in the most remote environments by destroying viruses, bacteria and protozoa-including Giardia and Cryptosporidium-in seconds."
The steriPEN works by emitting a germacidal dose of high-energy ultraviolet light into a sample of water. The UV rays destroy the DNA of the microbes contaminating the water. Without functional DNA, the microbes can't reproduce and make you sick.
If this is true, this is a remarkable breakthrough in backcountry water purification because the steriPEN weighs only 4.5 ounces.
Always Have a Backup Plan for Backcountry Water Purification
When out hiking with the family, we always have a water plan. We usually start by carrying 3-5 liters from home in a pack for a typical day-hike. As a backup we carry iodine tablets or a filter depending on the length of the trail. As a backup to this, we carry matches and some aluminum foil in the bottom of a pack.
You can use any combination of options listed above to create your own plan. The key is that you carry the right components, you know how to use them, and you know what to do if one should fail. By having a plan like this, you can easily mitigate the risks associated with dehydration in the backcountry.