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WHAT TO CONSIDER WHEN SELECTING A PORTABLE DRINKING WATER SYSTEM
Drinking Water Safety
Purifying your drinking water is a necessity. The only reason
to carry any drinking water purifier at all is to protect your
health against microbiological and chemical contaminants, hopefully,
while retaining the refreshingly delicious taste of mountain spring
water. Water-related health threats can occur any time you are
in contact with water:
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Drinking water directly.
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Using water as a food or beverage ingredient.
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Using water to clean cookware.
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Using water for hygiene, i.e., washing, brushing
teeth.
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During recreation such as swimming, skiing
or boating and rafting.
Common sense and precaution are necessary to reduce exposure
and to enable you to deal with these challenges.
Primary exposure to drinking water contaminants
occurs at the following times:
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When collecting raw water for purification...
we recommend using a container for your raw water supply whenever
possible, and be selective when possible, to choose a source
least likely to be badly polluted. Generally, water sources
at higher altitudes tend to be less polluted.
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During purification... be careful to prevent
dirty water from dripping or flowing into purified water.
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When storing your purifier either at meal
or camp sites, or in your carry pack.
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When handling the unit during storage, back
washing, brushing, scraping or maintenance functions.
Remember, the primary microorganisms of concern
in most wilderness recreation areas are tough, hardy cystic parasites
that resist heat and cold... even freezing... drought, chlorine,
iodine and just about everything else. And while bacteria are relatively
fragile and have very short life cycles, often less than a day,
cysts can exist for months. All microorganisms of chief concern
are invisibly small and they cannot be seen, smelled, or detected
in any quick and easy manner. Accordingly, you should assume that
all wilderness supplies are polluted.
Considerations
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It is widely known that Giardia and/or Cryptosporidia
have been found in water supplies essentially in every country
of the world. Therefore, you always should protect against
parasitic cysts and you should insist on 100% reduction. When
one cyst can infect, 99.9% may not be good enough, especially
when there is no known treatment for Cryptosporidia.
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There have been essentially no water-borne
typhoid, cholera or hepatitis Type A epidemics in the U.S. for
the last 50 years, so the likelihood of infection from U.S.
wilderness water sources is low.
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Pesticides and herbicides, and possibly other
chemicals, can be present anywhere downwind or downstream from
major agricultural and industrial areas hundreds of miles away.
These contaminants concentrate in streams, rivers and lakes
and sometimes are intentionally added for weed and aquatic life
control. Water Pollution, Biology, P.D. Abel, John Wiley &
Sons, 1989.
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Asbestos fibers can be found in very high numbers
of more than a million fibers per liter in most western and
in some eastern wilderness waters. Even though trace amounts
of these chemicals may not make you ill, no one wants to drink
asbestos fibers if they can easily be avoided.
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Micron ratings must be absolute to be meaningful,
and precise measurements are essentially impossible to make.
Micron ratings pertain only to physical removal or straining
of particles, so absolute micron ratings are only one means
of evaluation of effectiveness. Removal of pesticides, herbicides,
tastes, odors, most colors and solvents require other purification
(separation) mechanisms. Some product claims confuse retention
ratings by listing the size of microbes killed rather than the
actual retentions. For example, .01 microns, the size of some
viruses, is stated for some iodine products but actual retention
may be 100X bigger at 1.0 microns. Many units, even those
with very low micron ratings, have little or no ability to remove
anything other than particles.
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According to federal regulations "Pesticide"
products rely on chemically poisoning organisms (pests) while
"Devices" rely on physically removing them.
All products carry an EPA Establishment Registration Number.
"Pesticide" products also must carry a second EPA
registration number for the "Pesticide" being used.
So, decide if you want to use a "Device" or a "Pesticide"
product for your water purification needs, and be sure to check
the label to choose the right type. In certain applications,
it may be desirable to use a "Pesticide" to pretreat
water. Complete removal of the "Pesticide" is very
desirable after enough kill time has elapsed.
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Iodine used directly or from iodine resins
is not effective against Cryptosporidia and larger pathogens,
and most iodine resin based systems require double pass through
for effectiveness against viruses , especially at low water
temperatures. Some iodine resin systems require 10 minutes of
hold or kill time, in addition to double pass through, to achieve
99.99% reduction of viruses. There is no practical way to know
if a water source contains pathogens. This means that for consistent
virus and perhaps for bacteria reduction, when using iodine
resin systems, all water should be pumped through twice,
and then held for 10 additional minutes. It is essential that
carbon post filters not be used, as they stop pesticidal action.
General Ecology's First Need® portable water purifier removes
cysts, bacteria, viruses and viral toxins in a single pass.
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All prominent products being marketed today
carrying an EPA Establishment Registration number and/or a product
registration number are represented to meet all current, pertinent,
EPA and other federal regulations. Otherwise they should not
be permitted on the market, but EPA registration does not ensure
effectiveness.
So, now that you know why you need to purify and some background,
you can more intelligently select the right portable purifier
for your individual outdoor recreation needs.
A Water Purifier Should:
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Be effective
against the target contaminants it's supposed to remove, under
essentially any and all conditions to be encountered.
This seems self-evident but it isn't always the case. "Pesticide"
product effectiveness, in particular, varies and is affected
by temperature, concentration, time available, other chemicals
in the water (iron, nitrates, phosphates, etc.) and by silt,
mud, algae, organics, in some cases by pH, and the condition
of the unit. "Device" products typically are not affected,
or are little affected by most of these considerations.
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Signal
when it is working effectively, and, more importantly, perhaps,
when it is not working.
Again, this seems self-evident. With "Device"
products the signal is specific --- if water is coming
through it should be safe from particles including cysts, mud,
silt, etc., and possibly bacteria, depending upon the absolute
micron retention. "Pesticide" units give no signal
other than taste, which should be monitored with each use. "Pesticide"
units fitted with carbon post filters lack even this signal.
Resin systems rely on rapid and intimate interaction between
target organisms and iodine in the resins. Iron, mud, and silt
can coat the resins reducing or eliminating this interaction.
"Devices", annoyingly, can clog, but it's better to
know the end of capacity than to continue to rely on a process
that will continue to flow long after effectiveness is depleted.
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Protect
users from concentrations of pathogens accumulated on component
surfaces. Our immune systems often, especially in
the case of bacteria and viruses, can defend against low level
concentrations of bacteria while larger numbers of concentrated
pathogens will cause clinical illness. Therefore, concentrations
of pathogens should be contained, isolated, and made inaccessible
to users. For units requiring brushing, aerosolized residue
and backwash effluent present the potential hazards of post
purification inoculation and infection, sometimes by secondary
transfer - from filter surface to fingers to cookware or clothing
and then to mouth, for example.
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Remove
chemical hazards as well as microorganisms. Even
small amounts of some chemicals such as dioxin, for example,
can cause health problems and even minute traces can have long
term effects.
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Remove asbestos and other
microfine debris. A known carcinogen when inhaled,
asbestos is considered to be a possible carcinogen when ingested.
Mud and other debris can host a wide range of microscopic organisms
and parasites including cysts, bacteria, and viruses, and can
contain traces of pesticides. The largest U.S. waterborne disease
outbreak (in Milwaukee, WI) was attributed to debris encrusted
Cryptosporidia.
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Be convenient to use
and versatile. It's desirable
to be able to use a unit in pump mode or in gravity assist mode
and it should be straight forward to attach it to a trail bottle
or other storage bottle.
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Be designed
to avoid cross-contamination between inlet and outlet fittings
and hoses, and should have a sanitary cover to prevent contamination
of the outlet, even in campsite and meal preparation areas.
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Be field
maintainable with easily accessible pump parts. If
it can malfunction, it eventually will.
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Provide
deliciously refreshing drinking water, free of chemical taste,
odors, colors and sediment.
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Be rugged
and intrinsically reliable as to it's basic function, i.e.,
if it "works" it should produce safe drinking water.
It should not be easily damaged by freezing, dropping, tinkering,
poking or other general misuse. Preferably, some method of checking
integrity should be included or described, to check and assure
proper functioning after shipping, dropping or servicing the
unit.
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Be selected
for your particular mode of use.
Sometimes weight and compactness, after meeting all of the above
requirements, are prime considerations. At other times flow
rate, ease of use, ease of maintenance, flexibility of use or
other considerations will be more or less important. With the
wide selection of products available today you can choose what's
best for your intended use.
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Be reasonably
priced. Cost per liter usually is not a prime consideration,
and even convenience of use, while important, should be secondary
to effectiveness and dependability.
Finally, you should try to learn about various products you are
considering and also about the manufacturers. How long have the
products been on the market? Who has used them? Have they been
proven effective in preventing waterborne health hazards? What
about warranties, test results, customer service and other very
important factors? What other markets does the manufacturer serve
and who are its customers, (sophisticated users such as medical
research teams, airlines, and corporations can't afford mistakes
and often evaluate products thoroughly!)? All of these are important
factors and probably say more than editorial "choices"
and tabulated feature and fluff comparisons about your eventual
satisfaction with the systems you select to protect your drinking
water health. After all, you are the one responsible for your
own drinking water safety and health.
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