Medicine for the Outdoors
Medicine for the Outdoors

Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.

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From the aspect of preventing illness and avoiding disruption of an adventure, water disinfection is perhaps the most important skill for the wilderness and foreign traveler. Infectious diarrhea is rapidly debilitating and is a guaranteed loss of activity for 24 to 48 hours, minimum, unless you can recognize the early symptoms and treat aggressively with an effective antibiotic.

The SteriPEN™ carries the promotional byline of “safe drinking water anywhere.” Distributed by Traveler’s Supply, Inc., this unique hand-held water purifier that uses ultraviolet light (UVL) is advertised to fit into most plastic consumer water bottles as well as other types of containers up to 32 ounces (1 liter). It operates on 4 AA batteries, with nickel-metal-hydride or lithium batteries recommended. According to the distributor, only 48 seconds of exposure to the UVL is required to disinfect 16 ounces (1/2 liter) of water and 90 seconds for 32 ounces (1 liter). The claim is that the device is effective against common outdoor and household pathogens, as well as less common micro-organisms, to include bacteria, viruses, and protozoa. The test results are found at an Internet link provided by the company. According to the product literature, the SteriPEN™ meets U.S. Environmental Protection Agency standards for microbiological water purifiers.

A filter can be used to remove particulates from the water prior to UV treatment. At the current time, the selling price of SteriPEN™ Classic Handheld Water Purifier is $68.97 U.S.

Here are a few more details, provided by Traveler’s Supply, Inc. UVL works for water disinfection by destroying the DNA of microbes. This keeps the germs from reproducing, which is necessary in order for them to make a person ill. The light emitted by the SteriPEN™ device is in the UV-C range, of wavelength 254 nanometers. This wavelength is germicidal (kills germs) by causing adjacent thymine base nucleotides in DNA to bond together, which prevents them from being properly recognized (“read”) in the replication process, which is necessary for DNA to allow a micro-organism to reproduce. Thus, the germ(s) is rendered harmless. Used as directed, the UVL exposure is of no consequence, as this wavelength of UVL does not pass through most materials (e.g., glass, metal, ceramic, and nearly all plastics). Furthermore, the underside of the air/water surface in a water container acts as a reflector for UV-C. So, if the SteriPEN™ lamp is completely immersed in water and used according to the instructions, the UV-C is contained and does not pose any health risk to the user. For additional safety, the SteriPEN is equipped with water sensors and will not operate unless the lamp is under water. The SteriPEN™ contains a microcomputer that controls operation time, according to information it receives from integrated temperature sensors and user indication of the volume of water to be disinfected. During use, the device should be used to gently stir the water. It is intended for use in clear water, so cloudy water must be filtered or otherwise made clear prior to using the SteriPEN™. Disposable lithium or rechargeable AA nickel metal hydride batteries will provide many more disinfection cycles than will alkaline batteries. The latter are better in a cold weather situation.

I’m very eager to try out this device. In the wilderness, I drink boiled water or water that I disinfect with chemicals. It would be terrific to drink disinfected water without the iodine taste, and also to avoid burdening my body with the chemicals used to disinfect water. Combined with a filter to remove large particulates and clarify the water, this promises to be an excellent solution for water disinfection.

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About the Author

Dr. Paul S. Auerbach is the world’s leading authority on wilderness medicine.