Water

The following is from Santa Barbara Day Hikes by Ray Ford

“Water has more life in it than any part of the earth’s surface.”

Thoreau, Walden

Beware the crystal clear water—it may contain organisms known by the state of California to be harmful to your health. The culprit is known as giardia (pronounced gee-ar-de-a), a teeny-tiny protozoa that resides in the upper part of the small intestine, once ingested. Giardia has a life cycle that is composed of two stages. The first is the reproductive stage; the second the cyst, a stage in which the germ is encased in a hard shell. 

It is the second stage which causes the problem. The cysts remain alive in even the coldest water for as long as 3 months, even when frozen (don’t eat the yellow snow or even the stuff that looks as pure as Ivory flakes). As few as 10 of the little buggers can cause you to come down with giardiasis and if you’ve swallowed a hundred or more you’ll get it for sure.

Giardia comes from animal droppings or in some cases from human waste (always bury your waste in a hole at least 8” deep and never, ever closer than 100 feet from any water source). As the animals wade or wallow in a stream or pool the droppings enter the water. In some cases rain may wash the animal wastes into it. When ingested, the water-borne cyst attaches itself to the wall of your upper small intestine and your stomach’s heat activates it, causing it to go into the reproductive cycle, causing sickness and in the process producing more cysts. 

Though not life threatening, the disorder (giardiasis) it can be incapacitating, causing diarrhea, vomiting, gas (lots of it), loss of appetite, abdominal cramps, and bloating. These symptoms may last up to 6 weeks. In short, it’s no fun.

Even if the water is clear, cold, and free running it may harbor giardia cysts. They been found bubbling up from what appear to be the purest of springs. You can’t tell if they are present by the taste. Nor by the smell, or the look of it. The usual amount of time between ingestion and the onset of symptoms is about 2 weeks, meaning that you won’t know you’ve got it until quite awhile later and you might even mistake it for something else.

The best way to prevent the disorder is to bring enough water along with you so that you needn’t depend on what nature offers.  But this can be difficult to do on a long day hike and especially on a full day’s mountain bike ride. Other than bringing your own along there are really only 3 other choices: boiling, filtering, or chemically treating it. The surest way to destroy the giardia cysts, as well as other organisms, is to boil the water for at least a minute, preferably 3-5 minutes to be safe. Chemical treatment by use of iodine or chlorine isn’t considered as reliable as the use of heat, but it does provide a handy and relatively simple way to deal with the problem. Recent studies indicate that these chemicals may not work because they can’t penetrate the cyst’s hard shell. Use iodine rather than chlorine if you have a choice. It is more effective. Another drawback to use of these chemicals is that they make the water taste funny. 

What may be the most practical choice (especially if you backpack) is the use of a filtration system to remove the cysts. “First Need”, “H₂OK”, and “Katadyn Pocket Filters” all have been tested by the EPA and found to work on the giardia cyst.