[pct-l] To " Filter or Treat"...or not to..."Filter and Treat"
Yoshihiro Murakami
completewalker at gmail.com
Tue Sep 4 19:23:10 CDT 2012
Americans seems to love discussion, but I do not like and cannot
discuss, due to my poor English ability. I have already posted several
on this topic. So, I will show briefly.
This paper is a prospective study of 280 AT hikers. I cannot find
scientific study of PCT hiker. But the result of this study is
applicable to PCT hiker.
Boulware,D.R., Forgey, W.W. , Martin,W.J.II,
Medical risks of wilderness hiking. The American Journal of Medicine,
114, March 2003, Pages 288-293
Results
Of the 280 backpackers who responded (a combined 38,940 days of
wilderness exposure), 69% (n = 192) achieved their goal. The most
important reasons for ending a hike prematurely were injury, time
limitation, and psychosocial reasons. The most common medical
complaints were feet blisters (64%; n = 180), diarrhea (56%, n = 156),
skin irritation (51%, n = 143), and acute joint pain (36%, n = 102).
The incidence of vector-borne disease was 4% (n = 11);
physician-diagnosed Lyme disease was the most common, and 24% of
hikers (n = 68) reported tick bites. The risk of diarrhea was greater
among those who frequently drank untreated water from streams or ponds
(odds ratio [OR] = 7.7; 95% confidence interval [CI]: 2.7 to 23; P
<0.0001), whereas practicing “good hygiene” (defined as routine
cleaning of cooking utensils and cleaning hands after bowel movements)
was associated with a decreased risk (OR = 0.46; 95% CI: 0.22 to 0.97;
P =0.04).
Conclusion
Diarrhea is the most common illness limiting long-distance hikers.
Hikers should purify water routinely, avoiding using untreated surface
water. The risk of gastrointestinal illness can also be reduced by
maintaining personal hygiene practices and cleaning cookware.
----The importance of good hygiene was clearly indicated. But, it also
disclosed the relation between water treatment and diarrhea. That is,
water treatment has some effect to prevent diarrhea by simple
reasoning. The good hygiene and water treatnent are both important.
----This article also maintained that the high frequency of water
disinfection was observed who drunk the suface waters ( streams, ponds
). Spring Water was relatively safe.
Another article is the most recent scientific article, which I found
by consulting PubMed, on 'Sierra Nevada' and 'water'
J Environ Public Health. 2012. Impact of summer cattle grazing on the
Sierra Nevada watershed: aquatic algae and bacteria. by Derlet RW, et
al.
This is a free article:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312331/pdf/JEPH2012-760108.pdf
Abstract
We evaluated periphytic algal and microbial communities to assess the
influence of human and cattle impact on Sierra water quality.
METHODS:
64 sites (lakes and streams from Lake Tahoe to Sequoia National Park,
California) were sampled for suspended indicator bacteria and algae
following standardized procedures. The potential for nonpoint
pollution was divided into three categories: cattle-grazing areas (C),
recreation use areas (R), or remote wildlife areas (W).
RESULTS:
Periphyton was found at 100% of C sites, 89% of R sites, but only 25%
of W sites. Eleven species of periphytic algae were identified,
including Zygnema, Ulothrix, Chlorella, Spirogyra, mixed Diatoms, and
Cladophoria. Mean benthic algae coverage was 66% at C sites compared
to 2% at W sites (P < 0.05). The prevalence of E. coli associated with
periphyton was 100% at C sites, 25% of R sites, and 0% of W sites.
Mean E. coli CFU/gm of algae detected was: C = 173,000, R = 700, W =
0. (P < 0.05). Analysis of neighboring water for E. coli bacteria >100
CFU/100 mL: C = 91%, R = 8%, W = 0 (P < 0.05).
CONCLUSION:
Higher periphytic algal biomass and uniform presence of
periphyton-attached E. coli corresponded to watersheds exposed to
summer cattle grazing. These differences suggest cattle grazing
compromises water quality.
---The quality of water is good at Wild site, but the quality worsen
in Recreational and Cattle site. You can get safe water from the wild
site, but you should be more careful to get water from the
Recreational and Cattle site.
This is the list of their defined site. Wild site is very limited by
my impression.
----------------------------------
Wild sites
----------------------------------
Golden Bear Lake,KC
West Window Creek,
Marie Lake, Muir
Silver Pass Creek, Muir
Silver Pass Lake, Muir
Chief Lake, Muir
Lake Virginia, Muir
Granite Lake, Yos
Gaylor Lake, Yos
Conness Creek, Yos
Upper Young Lake, Yos
Townsley Lake, Yos
Lake 12,248 m, KC
Bago Springs, KC
Glen Pass Spring, KC
Creek from Lake 10320 m, KC
-----------------------------------
Recreational sites
-----------------------------------
Charlotte Lake, KC
KC Bullfrog Lake, KC
Smith Lake, Tahoe
Bubbs Creek, KC
Rae Lake (Mid),
Rae Lake (Lower), KC
Arrowhead-Dollar, KC
Dollar Lake, KC
SF Kings River, KC
Lake 12,500 m, JMT, KC
Kearsarge Lake, KC
Booth Lake, Yos
Fletcher Creek, Yos
Fletcher Lake, Yos
Vogelsang Lake, Yos
Ireland Lake, Yos
Ireland Creek, Yos
Tuolumne River (High), Yos
Tuolumne River (Low), Yos
Young Lake, Yos
Side Creek/Young Lake, Yos
Dog Lake, Yos
Middle Young Lake, Yos
Duck Lake, Muir
Purple Lake, Muir
Fish Creek, Muir
Squaw Lake, Muir
Hilgard Creek, Muir
Mono Creek, Muir
Robinson Creek, Hoover
Barney Lake, Hoover
Fremont Lake, Hoover
West Walker River, Hoover
Long Creek, Hoover
Toejam Lake, Emigrant
Silver King Creek, Carson
-------------------------------------
Cattle sites
-------------------------------------
Cottonwood Creek, Stan
Boggie (High), Stan
Boggie (Mid), Stan
Boggie (Low), Stan
KC Cow Creek, Stan
Little Walker River, Hoover
Molybdenite, Hoover
Buckeye, Hoover
Big Meadow (High), Hoover
Big Meadow (Low), Hoover
Summit Lake, Tahoe
Bull Creek, Carson
--
Sincerely
--------------- --------------------------------------
Hiro ( Yoshihiro Murakami 村上宣寛 )
facebook http://www.facebook.com/completewalker
Blogs http://completewalker.blogspot.jp/
Photo https://picasaweb.google.com/104620544810418955412/
Backpacking since about 1980 in Japan
JMT, 2009, 2010, 2011(half).
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