[at-l] Water Purification Issues

[icw@xxxxxxxxxxx (Clark Wright)]

Weary's comments are well worth considering; here are a few random
thoughts sparked by his e-mail, and some others I've received off-list:

1)  Dioxin contamination of southern rivers, and bioaccumulation of the
stuff in fish has been a big EPA issues over the past 20 years - much of
the dioxin in southeastern river sediments was created as a by-product
of all the chlorine dioxide bleach used by pulp and paper mills; I say
this not to sound like an alarmist - I actually think some of EPA's
actions are overreaction on this issue - rather, I say it to simply
point out that use of chemicals often has unintended and longer term,
chronic consequences that are hard to identify or quantify in terms of
potential human health hazards, either at the outset, or even after
having 20+ years of data . . .

2)  The issue of water purification is intensely personal, both due to
varying stages of immune system vitality and legitimate, varying levels
of personal preference/fears or concerns.

3)  The one "study" I know of with some relevance concluded that there
was little statistically valid difference between hikers who used no
purification, versus filters, versus chemicals . . . I cannot recall the
study name, author, etc. but I think that's what the conclusion was.

4)  If you are "one-potting" it for cooking, just let your water boil a
bit longer and that habit alone will likely kill most "bad" stuff.

5)  The lightweight in-line filters that you can cut and plug into your
hydration bag/tube system, and the built-in water bottle filters are a
nice complement to boiling and just being common sense careful re the
water sources you use.

6)  Remembering to refill fully while in town can also help [with the
caveat that the largest hiker water-related disease outbreak I know of
was caused by hikers filling up from a contaminated hostel water source.]

In short:  Lots of options or combinations of options are out there, and
you have to make your own informed, personal choices - and there clearly
is no single, "right" answer.

thru-thinker
Bob C. wrote:

> Chlorine dioxide is a standard industrial bleach. The pulp and paper industry
> uses it by the many tons a day at a cost of pennies a pound.
>
>  No chemical removes all of the potentially dangerous things that may be found
>  in trailside water sources. Very few hikers are willing to wait the time needed
>  for the chemicals to reach their maximum killing rate.
>
>  Someone praised chlorine dioxide because it "dissolves instantly." I'm guessing
>  the hiker meant by this that he could, therefore, drink the water instantly.
>  The manufacturer, however, says to be effective, two chemicals must be mixed
>  together, allowed to sit for five minutes, then poured into the water, and the
>  water then allowed to sit for another half hour before being consumed.
>
>  The manufacturer's ad doesn't say at what temperature a half hour wait is
>  enough. I suspect, however, that in water from cold March streams the time may
>  be several hours. I've never had an opportunity to read the fine print in the
>  manufacturer's directions, mostly because I'm reluctant to invest $7-$8 an
>  ounce for stuff that I suspect the mills and water utilities spend pennies a
>  pound for. However, if anyone has bought the hiker variety, I'd love to hear
>  what the fine print says.
>
>  However, from what I've read over the years, mountain streams are far less
>  dangerous then all the ads and speculation would lead one to believe. We treat
>  our water in the hills as if it had come from an over-populated third world
>  ditch.
>
>  This may be a legitimate precaution. But in years of reading the literature and
>  postings of forums like this, I've yet to see anything that strikes me as
>  scientific evidence. Rather the evidence strikes me as leading to a contrary
>  conclusion -- that very few hikers get sick from dirty water -- but a lot get
>  sick from personal inadequate camp and hiking sanitation, and contact with
>  other hikers who practice inadequate personal camp and hiking sanitation.
>
> There's a very complex chemistry involved in trail water purification, which I
> don't pretend to know. But chemicals don't remove pesticides and herbicides and
> other chemical contaminants, which are probably at least as dangerous and as
> likely to be found as giardia or crypto.
>
> Chlorine, and maybe iodine since they are related elements, combine with organic
> matter in the water to produce particularly potent disease-producing substances.
>
> Though all of the popular chemicals certainly are capable of killing some
> disease organisms, none of them will kill all such organisms.
>
> It is beyond my powers of statistical analysis to say what this means in terms
> of overall protection if you are using the chemicals over a six month hike.
>
> I can tell you my practice over several decades. I have yet to get sick with
> anything that seems related to drinking water. For most of those years I just
> drank whatever water I found and didn't worry about it.
>
> For the past decade or so, I've taken to drinking out of "cold" water sources
> like springs without treatment. In lowland areas where pollution is more likely,
> I try to boil a couple of quarts of water each evening on my wood-burning zip
> stove in case I can't find any cold springs the next day.
>
> On my '93 hike I carried some Army surplus iodine tablets and used two or three
> of them when the water looked suspicious.
>
> What was the question? Oh. You asked about Katahdin Micropur tablets. I have no
> idea.
>
> Weary
>
>
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