Water Treatment on Wilderness trips

Proper sanitation and water treatment are important steps in preventing disease from being trasnmitted on backpack trips. Our Sierra Club Knapsack trips provide 4% tincture of Iodine for water disinfection for each trip member. What each person does with their personal water is of course their own decision. We provide the 4% Iodine tincture as it is lightweight, 100% effective, and easily transported.

All food prepared for group consumption is made with water that has either been heated to sufficient level to kill cysts, bacteria, and any other organisms or has been treated with Iodine tincture (as in the preparation of some cold sauces). Whenever possible, extra boiled water is reserved at night time for use with the morning's meal. This helps keep the faint taste of Iodine out of milk, for example.

Some people dislike the taste of water treated with Iodine. A simple solution is to use less, and let the water treat for a longer period. Another quite efective and simple way to remove the taste of Iodine is to sprinkle a pinch of lemonaid mix into a bottle of treated water. The ascorbic acid in Lemonaid combines with the Iodine to make Iodide, which is salty but so small and dilute you can't taste it. Iodine tincture must never be added to water that already contains lemonaid or any other additive, or it will be rendered ineffective.

Giardia Cysts, Parasites, Bacteria, and Virus Disinfection

Following are directions for the proper use of the 4% Iodine tincture provided on Knapsack trips.

The rate at which micro-organisms are destroyed is dependent upon the Iodine concentration, the contact time, and the water temperature.

One fourth the standard concentration needs four times the contact time.

Cloudy, heavily contaminated water needs double the Iodine concentration

	Time	Water Temperature
4 drops solution / quart	10 min.	56 F (Sierra stream water)
4 drops solution / quart	30 min.	34 F (Glacial melt)
2 drops solution / quart	20 min.	56 F (Sierra stream water)
2 drops solution / quart	60 min.	34 F (Glacial melt)
4 drops solution / gal.	8 hrs.	56 F (Sierra stream water)

IODINE TOXICITY: The rare person who is allergic to iodine must not use iodine for water disinfection. Persons with known thyroid dysfunction should determine how they react to water containing iodine at home before using iodine for water disinfection while traveling.

HEAT FOR WATER DISINFECTION

Hot water (140 F) will destroy Giardia in two or three minutes! For any other micro-organism, water is safe to drink by the time is is brought to a boil at 14,000 feet (186 F). Time and temperature are adequate to kill all disease producing micro-organisms.

Late-breaking News

Please read this paper. It details a study of stream water in the Sierra Nevada, and provides strong data in support of not being overly concerned with water quality in the Sierra Nevada. We will continue to treat all water consumed in group meals, but it appears to be safe to relax a bit with our personal consumption straight out of the stream.