Water Your Options?

August-September 1997

This is an article from WaveLength Magazine, available in print in North America and globally on the web.

Backup your self rescue methods

by Deborah Leach

Deborah Leach gave a demonstration on water filters at this year's Ocean Kayak Festival. As a nutritionist and our Paddle Meals coordinator, she's concerned with clean water. Here are her thoughts on water filters.

Paddling past towering spruce and drooping cedar, you hear the familiar rush of a creek and veer over to fill your drinking bottle with cool, fresh water. Is it safe to drink?

Gone are the days when you could confidently drink from a mountain stream, alpine lake or forest pond. Today, even remote watersheds contain microbes which expose back country travellers to water-borne disease. Health officials warn that even water from "pristine" wilderness areas, glaciers and alpine snowfields is considered unsafe to drink.

What's in the water?

Untreated water may carry disease-causing parasites, bacteria and viruses passed on through the feces of infected humans and animals.

Giardia ("beaver fever") and its cousin Cryptosporidia are parasitic protozoa of concern to paddlers. A recent study, reported in Backpacker, showed that samples from 10,000 US streams all contained giardia cysts. Environment officials indicate the situation is the same in British Columbia. Giardia gets into the water because lakes and ponds are toilets for beavers and muskrats. Outbreaks of "crypto" carried by cattle, deer, elk and humans are all too common. Water-borne bacteria, most commonly Campylobacter and E. Coli, can also cause nasty "gastro" upsets. Viruses that you want to "avoid like the plague" are Hepatitis A and the Norwalk virus.

Many infected people don't feel sick while others think they have the flu somewhere between two and ten days after drinking the "bad" water. Diarrhea, stomach cramps, nausea, vomiting, headache, fever and fatigue are no fun while you are out kayaking. If you get sick, there is no treatment for Crypto or viruses and you may need prescription drugs to combat other infections. Contact your public health unit for more information on how to prevent water-borne illness.

Safe options

On kayak trips, each person needs at least 2 litres of fresh water per day for drinking, brushing teeth, rinsing contact lenses or dentures, preparing meals, washing uncooked fruit and vegetables. If you have room in your boat, bringing enough water for your whole trip is the simplest solution. If you take commercially bottled water, it should be purified by ozonation, reverse osmosis or distillation.

On longer trips, your choices narrow. Boiling water for three minutes will kill all viruses. Most bacteria and protozoa are dead by the time you see the first bubbles. This works if you have time, enough fuel and want a hot drink or meal anyway. Since boiling leaves water with a flat taste, you can shake your container to aerate or add a wedge of lemon or beverage crystals for a tastier beverage.

Since the advent of the supercyst "crypto," you can no longer rely on iodine or chlorine alone to treat your water, so filtering is the obvious solution. To cover all bases you need to filter out the larger microbes and use chemicals to kill the viruses which slip through even the smallest holes. Filters with an "absolute" (no holes are larger than this) pore size of 0.2 microns or less will capture most bacteria as well protozoa (which are larger).

Gadgets that both filter and disinfect are called purifiers. To neutralize the odour and taste of iodine and chlorine, some devices have carbon filters. Or you can use half the recommended dose of chemicals and double the contact time after filtering. Or add lime juice concentrate or drink crystals after contact time is complete. Some companies make tablets designed to improve the taste of the water.

Filters use either ceramic or glass fibre as the primary means of removing microbes. Ceramic versions cost more, but can be cleaned repeatedly resulting in a lower cost per litre. Ceramic needs to be handled gently and drained completely in cold weather or it will crack. Glass fibre is flexible and less fragile, but can only be cleaned so many times before it clogs for good. As with any gadget, look before you leap. Filtering takes time, plus the pumps and replacement cartridges are expensive. Health officials stress the importance of maintaining your filter so it performs properly.

Salut!

Deborah Leach, her kayak and computer are based in Victoria.

Editor's Note: We reported in an earlier issue the suggestion that letting water sit in the direct sun in a clear container for a number of hours has disinfecting qualities.