Just found this on a travel site.

Contaminated drinking water is the most common source of health problems while traveling, with gastrointestinal distress the most common sympton. Unfortunately, the mere inconvenience of multiple trips to the water closet may be the least of your worries. Contaminated water can also induce amebiasis, cholera, cryptosporidiosis, dysentery, giardiasis, hepatitis A, and rotavirus-caused gastroenteritis.

Bugs, Parasites, and Other Contaminants You're up against a varied army of potentially injurious contaminants while traveling. Most microorganisms are killed when boiled sufficiently. Bacteria include E.coli, cholera, salmonella, and others; bacteria respond well to filters with small pores, and chemical treatments. Protozoa include giardia and cryptosporidium, and respond well to filtering due to their relatively large size. Viruses include hepatitis A, polio, and rotavirus, and are very difficult to filter due to their very small size; chemical treatment works best for viruses.

Additionally, chemical pollutants, particles and debris, and other contaminants can cause problems. These are less likely to respond to boiling, and may require a combination of treatments.

These conditions are not limited to developing countries. Cryptosporidium outbreaks have appeared in the U.S Midwest and Northwest, and even Scranton, Pennsylvania, as well as in highly populated cities in Australia. Giardia is found in the water supply in St. Petersburg, Russia.

Some cities may advertise their drinking water as being chlorinated; this doesn't necessarily mean that the water is contaminant-free.

Avoidance is the First and Best Policy Your best approach when faced with potentially unsafe drinking water is avoidance. Tap water, as well as ice, is anathema.

What You Can Drink In general, the following sources are safe: - boiled water - hot beverages made with boiled water, such as tea and coffee. Coffee from a machine is usually safe. - canned or bottled water, seal unbroken; carbonated water is best, as you are guaranteed that it is not merely tap water - carbonated beverages - beer - wine

Tips Drink bottled water Make sure the seal is not broken; there have been cases of vendors filling water bottles with tap water. If the containers are chilled in ice, be sure to wipe off water from the opening of the bottle or can. Use a straw when in doubt.

Drink commercial products Soda, carbonated beverages of any type, beer, wine, and the like are usually safe. Again, if the containers are chilled in ice, be sure to wipe off water from the opening of the bottle or can.

Brush your teeth with safe water Brushing your teeth with contaminated water will have the same effect as drinking it outright. Don't brush your teeth in the shower.

Avoid ice Unlike boiling, freezing water does not kill the parasites that may infect travelers. The margarita on the rocks may sound appealing, but the ice cubes present the same problems as does tap water. You can make your own ice if you boil the water first.

Block ice is especially suspect. Some travelers trust cube ice, but a safer option is to avoid ice altogether.

Showering, Bathing, Contact Lenses and Denture You don't need to drink contaminated water to be exposed; always consider alternate sources of exposure.

Showering and bathing present little worry, as long as you do not drink the water or brush your teeth in the shower.

Wash contact lenses and dentures in water you trust.

Water Purification Tactics Boiling Boiling water is the most effective tactic for removing all parasite contamination. Water should be boiled for at least 10 minutes or longer, especially at high altitudes, where the boiling point will be lower, and some parasites might not be killed as quickly. Allow any sediments and particles to settle before drinking, and then decant the water from the top into another container.

An immersion coil is inexpensive, small, and can serve admirably. Magellan's sells these and most of the other products mentioned below.

Note that boiling will not eradicate chemical contamination, such as might be found in a polluted stream. Again, allowing sediment to settle, and decanting the top water, is always a good idea.

Tablets Iodine or chlorine, commercially available as water purification solutions, can be a satisfactory solution in many cases. However, long-term use can cause these compounds to build to unhealthy levels. Additionally, iodine and chlorine do not remove particulate contaminants, are unhealthy for pregnant women and thyroid patients, and do not kill some parasites, such cryptosporidium.

Iodine is the more effective of the two solutions. Potable Aqua, composed of the iodine compound tetraglycine hydroperiodide, is the most popular brand of water purification tablet. Read directions on all tablets systems for tablet-water ratios and dissolving times; it may require 20 minutes or more to dissolve the tablets completely, especially for colder water.

Chlorine Bleach If you do not have tablets, putting two drops of common chlorine bleach in a quart of water will help in a pinch.

Water Filters and Purification Pumps Available at outdoor and camping stores, this may be the best and fastest option, especially for hikes or trips to remote areas where finding commercial bottled water may be difficult or impossible. It is essential that the filter system you choose is suited to your needs, however! A filter with an insufficiently small pore size, or that is not designed to filter viruses, may permit some contaminants to pass unmolested.

REI maintains an excellent primer to water filters and purification systems.

Filter/Chemical Combination Bacteria are more easily filtered than viruses, but are resistant to chemical treatment; the opposite is true for viruses. Many filtering/purification systems combine the two methods; you can do the same with a makeshift program of filtering and chemical (iodine) treatment.

Hot Water Bottles Prolonged exposure to higher temperatures will kill many parasites in the process called Pasteurization, used for milk. As a result, drinking from a hot water bottle is slightly safer than drinking untreated cold water.

When to Damn the Torpedoes If locals are drinking the tap water without ill effect, there is no known occurrence of giardiasis, and you are going to be staying in one location for four weeks or more, you may want to drink the water to allow your body to acquire some of the local microbial flora and fauna. Start slowly to allow your body time to adapt; a good way to start is by brushing your teeth. This can be an uncomfortable solution, at best, and a risky one, at worst.

Have Information to Share? Join other members on the Health, Safety & Insurance message boards to share your water purification tactics.

Copyright 1999, The Independent Traveler. All Rights Reserved.

This file may be downloaded by America Online subscribers for personal use only. Other copying or reproduction is expressly prohibited.

-- Mumsie (Lotsakids@home.com), June 30, 1999