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By Tamia Nelson July 16, 2002
A gentle breeze ruffles the lake surface
under a brilliant blue sky, but the moving air does little to cool your
sweating body. The noon sun is so hot that it feels as if it's drilling a
hole down through the top of your head. Your mouth is dry, and your
tongue feels swollen. You need a drink. Now.
You stop paddling. Your boat drifts with the wind. You rummage around
in your pack and pull out your water bottle, only to find that the cap
has come loose. All the water has seeped away into your spare clothes.
Except for a few tepid drops, the bottle is empty. You look around you.
Wavelets lap tantalizingly against your hull. The lake is crystal clear.
You can see the bottom. It must be twenty feet down, but it seems as if
you could reach out and touch it. Then you bring the water bottle to your
parched lips and tilt it up. The last drops run into your mouth, but they
do nothing to quench your raging thirst.
You soak your bandanna in the lake and wash the salt crust from your
face and neck. You dip it in the water again, then tie it around your
neck. You lick a few drops of water off your lips. Heavenly!
Water, water, everywhere…. And why not take a drink? You study
the shoreline. A few cottages are just visible in the distance.
Surely, you think, they wouldn't…. They aren't….?
You shake your head. You sigh. Then—quickly, so you won't have time
to change your mind—you hold your water bottle over the gunwale.
Lake water flows into the open neck, filling it in no time. You lift the
bottle to your lips. Cool water gurgles down your throat.
Ahh….
Satisfied now, you refill the bottle, check to see that the cap is
secure, and stow it away in your pack. By the time the sun has dipped
below the trees to the west, you're at the take-out, loading your boat
onto the van. In less than an hour, you're seated at an outside table at
Hog Heaven. The waitress puts a cold beer in front of you and tells you
that your order of ribs is on the way. You smile your thanks and settle
back. Life doesn't get any better than this, you think.
Two hours later, you pull into your driveway. You're exhausted. You
leave the boat on the van, take a quick shower, and go to bed. You fall
asleep in seconds.
The first cramps hit at four o'clock in the morning. You make it to
the bathroom in time, but the vomiting starts before you can get up off
the toilet. The next three hours are best forgotten. You skip breakfast
and call in sick. The boss isn't very happy, but you don't care. You
think you're lucky to be alive. Then you head for the doctor, hoping that
she can fit you in. She can—just. She gives you a quick once-over
and tells you that you have a "stomach virus," or maybe "beaver fever."
Then she leaves. Her nurse hands you a prescription and tells you to
drink plenty of water.
Water! you think. That's what caused all this trouble!
But you don't say anything. You're already feeling better. You put the
prescription in your wallet and stock up on bottled water at the
Quik-Mart. You're not taking any chances.
A month passes, and you're back on the lake. It feels good to stretch
your muscles again, to feel the hot sun on your face, to revel in the
freedom of the water. Around noon, you stop for lunch: a thick ham
sandwich and a couple of big chocolate chip cookies, along with some
salted peanuts to finish things off. Then you grab your water bottle.
You've learned your lesson. The cap's screwed down tight. You loosen it
and upend the bottle over your open mouth. Water—safe
water—pours out. You drink greedily. When you finish, the bottle's
almost empty. Guess I should have brought another bottle, you
think. Still, you've quenched your thirst. And anyway, there's nothing
you can do about it now.
The long summer afternoon passes slowly. The temperature climbs. You
sweat. Salt stings your eyes. Your mouth is dry. But your water
bottle—your only water bottle—is empty. You look out at the
lake. Its water is cool, clear, inviting. Then you remember the morning
after your last trip. There's no way I'm going through that again!
you tell yourself. So you paddle on through the furnace of the day.
Later, at the take-out, you're a little sick to your stomach. You're
light-headed, too, and you feel weak and washed-out. You even have
trouble getting your boat on the van. You stop at the first roadside
stand you come to and order two large root-beers. You drink both of them,
then order a third. It does the trick. Your head clears. You feel
stronger. You drive away refreshed. The next time, you promise
yourself, I'm going to bring at least a gallon of water from home.
And you do.
Get the picture? Paddling's sweaty work, and you need plenty to drink
if you want to stay healthy. But you can't assume that the water you
paddle is safe. No matter how clear it is, it can still harbor dangerous
microorganisms, or even toxic chemicals. There's no rule of thumb to
distinguish good water from bad, and no simple test. The only universal
guideline is the one promulgated by veteran desert walker (and occasional
paddler) Colin Fletcher: "When in doubt, doubt." And sadly, there's
almost always good reason to doubt the safety of the water around you.
Don't blame the beaver or other wild animals, though. Notwithstanding the
"beaver fever" tag, the culprit in most cases is…you guessed
it…us: paddlers and other boaters, waterfront property
owners, or town and village sewage systems, not to mention our pets and
our industries.
OK. The water's probably not safe to drink. What can you do about it?
The first and most obvious alternative is to bring good water from home.
There's a problem, though. A US pint of water (about half a liter) weighs
a little more than a pound, and you need at least a gallon of fresh water
each day. That's more than eight pounds! (Think a gallon is a lot of
water? The US Army's desert warfare allowance is eight
quarts—two gallons—a day. And the Israeli Defense Force
go even further: heat illness is a court-martial offense, and they
provide each soldier with a daily ration of ten liters—more than two
and one-half US gallons.)
Eight pounds (or more) of water, each and every day. That's all right
on a day trip, or even on a weekend—if the portages aren't too
steep!—but it's not very practical on longer voyages. That leaves
you with just one choice: treat the water to make it safe.
But how? No treatment can make chemically contaminated water fit to
drink, of course. Still, chemical contamination isn't thought to pose a
danger in most back-country areas. And how can you tell if it's a problem
where you want to paddle? You'll have to rely on local knowledge. So ask
around. Contact paddling clubs. Natural resource agencies. Public health
authorities. Even local universities. And hope that you get honest
answers.
Happily, you can do something about microbial
pathogens—nasty bugs, in other words. Boiling works fine, for
instance. But boiling water takes time and fuel, and even regular
tea-drinkers may find that a hot cuppa doesn't do much to quench their
thirst on a steamy summer afternoon. (In fact, tea and coffee both
contain caffeine, and caffeine is a diuretic. It makes you pee. So coffee
and tea can actually increase the threat of dehydration, at least when
drunk to excess.)
All right, then. If boiling's not practical, what about filtration?
It's a popular choice. The catalogs are full of water filters. And for
good reason. Filtration works well, provided that the filter is carefully
maintained and the "bugs" in the water you're filtering are fairly large.
Most filters do a good job with the cysts of protozoan parasites (the
misnamed "beaver fever" organism Giardia, for example) and
bacteria. But tiny viruses can slip right through the filter pores, and
that's not good news, because viruses—among them the hepatitis
complex—are among the ugliest of waterborne nasties.
This is a problem. If filters can't remove some of the deadliest
pathogens, what's a paddler to do? The answer, I'm happy to say, is
simple: treat any water drawn from lake, stream, or spring with a
chemical biocide. Iodine is the chemical of choice, and tetraglycine
hydroperiodide tablets (sold under the trade mark Potable Aqua®) are
the easiest way to deliver a measured dose. One tablet in a quart of
water will yield a concentration equivalent to 8 milligrams of free
iodine per milliliter (that's 8 parts per million, or ppm). Given
adequate time to do its work—a "contact time" of ten minutes or
more—this concentration is high enough to reduce the numbers of
bacteria, viruses, and most protozoan parasites to safe levels.
Is there any downside to iodine? Yes. People with thyroid disorders
or iodine allergies should not drink water disinfected with tetraglycine
hydroperiodide (or any other iodine-releasing compound, for that
matter). And tetraglycine hydroperiodide tablets must be fresh to do
the job. They should be stored in a tightly capped bottle and kept in a
cool, dry place. Any tablets left over at the end of the season should be
discarded. The water to be treated must also be comparatively warm and
clear. If it's cloudy or cold—less than 40 degrees Fahrenheit,
say—double the dose to two tablets per quart, and double the contact
time (to 20 minutes) as well.
Anything else? Yes. At concentrations of 8 ppm (or more), iodine
imparts a distinct—and, to some people's palates, distinctly
unpleasant—taste to water. This taint can be removed by subsequent
chemical treatment or activated carbon filtration, but there's another,
simpler alternative. Concentrations of as little as 0.5 ppm will kill all
but the most resistant encysted protozoan pathogens. That being the case,
if you're traveling outside the tropics, if your immune system is up
to par, and if you're willing to run the usually very small risk of
giardiasis (a subject of "exaggerated concern," in the words of one
authority, the invaluable Medicine for Mountaineering), then, and
only then, you may wish to treat drinking water in bulk, using just
enough tetraglycine hydroperiodide to yield a final concentration of 1
ppm: one tablet per two gallons of (clear) water. To be on the safe side,
allow a minimum one-hour contact time, too.
This is what Farwell and I do, and we've been happy with the results.
The iodine taste is barely discernible, yet the treated water is as free
of microbiological hazard as the stuff that comes out of most urban taps.
(Few municipal systems filter out cysts, and chlorine can't always be
relied upon to kill Giardia.)
Of course, there's no reason why you can't combine chemical treatment
and filtration. Just treat your water with iodine tablets and then pump
it though a filter. It's the belt-and-suspenders approach, and it ought
to provide a very high level of protection, indeed. In fact, several
commercial water filters formerly incorporated iodine-impregnated
elements, thereby attacking microbial contamination in two ways at once.
I can't find any of these in my current catalog collection, though.
Water, water, every where/Nor any drop to drink. Unfortunately,
the Ancient Mariner's familiar lament is often as true of today's
recreational waterways as of Coleridge's "painted ocean." And even a
little thirst is a dangerous thing. No paddler can afford to be without
plenty of clean water. "Clean"—that's the critical word. So when in
doubt, doubt. It's the only safe rule. Once you've treated your water,
however, you should be able to put those doubts to rest. Then you can
drink a toast to your good health with confidence. Salut!
Copyright © 2002 by Verloren Hoop Productions. All rights
reserved.
Alimentary, My Dear
Water, Water, Everywhere,
But Not a Drop to Drink?
tamia@paddling.net
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