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[pct-l] Re: It's the water



I don't know how mcuh faith I would put in his reaserch. I have read 
sevral studies he has doent hat have later proved he fudged the resultes

O David wrote:

>Germs can lurk in water bottles
>By Cathryn M. Delude, Boston Globe, 6/3/2003 
>
>Summer's coming, and thoughts turn to the great outdoors. Before grabbing a
>water bottle and heading out, think about that bottle and how to keep its
>contents clean. 
>
>Water bottles are not all created equal. Soft plastic bottles bend and
>crinkle, giving bacteria a place to establish a beachhead, according to Ryan
>Jordan, a researcher at Montana State University's Center for Biofilm
>Engineering. Bottles made of hard, unbreakable Lexan plastic don't have that
>problem. Still, over time, bacteria from your mouth or the environment can
>grow in any bottle, especially if it contains sweet sports drinks or becomes
>warm. 
>
>No one has actually studied how many people get sick from water bottle
>bacteria, yet there are ample warnings about water-quality problems
>encountered by hikers in the back country. All streams and ponds are
>supposedly contaminated with microbes spread by wildlife, and humans and
>their animals. These microbes include giardia, fecal bacteria, and
>cryptosporidium, which cause various gastrointestinal problems such as
>diarrhea, cramping, and bloating. 
>
>To prevent diarrhea on the trail, hikers are warned to use water filters,
>which strip the microbes from the water, or iodine tablets, which kill many
>microbes (but not cryptosporidium). These warnings, however, are not based on
>scientific investigations about the actual risk of water-borne disease in the
>back country or the effectiveness of water-treatment methods on the trail,
>according to Jordan. 
>
>During the past two years, his research group decided to assess the water
>quality in streams and lakes at popular recreational areas, such as
>Yellowstone National Park and the Appalachian Trail, where they could expect
>to find bacterial contamination because of the numerous hikers. Indeed, they
>found that gastrointestinal problems are uncomfortably common on the trail.
>For example, of the 120 hikers who had been on the Appalachian Trail for
>three months or more that Jordan interviewed for his study, 90 percent had
>suffered gastrointestinal problems, and 20 percent had problems within the
>first week. 
>
>The prevalence of gastrointestinal infections among hikers might make it seem
>as though there were high levels of microbes swimming around in back-country
>water. On the contrary, Jordan found the water had very few microbes swimming
>about. 
>
>But the coating on rocks and sediment at the bottom of streams and ponds, as
>well as the thin surface film on standing water, did contain the usual
>suspects. These microbes grew in a slime, which scientists call a biofilm. 
>
>If you stir up the sediment or slurp in the surface film while filling your
>bottle, you gather biofilm clumps with your water. ''If a biofilm clump
>contains a thousand bacteria,'' Jordan explained, ''there's a much higher
>chance of getting sick than if you drank the same number of free-floating
>individual cells.'' By virtue of living together in large, attached groups,
>bacteria in biofilms become more virulent and resistant to the helpful
>bacteria in your gut that normally eliminate foreign intruders. 
>
>Biofilms can also foil trailside water-treatment efforts. Iodine tablets
>can't sterilize biofilms, and biofilms clog water filters. 
>
>In fact, all the hikers in Jordan's study who had been on the Appalachian
>Trail for three months or more had experienced filter failure. ''The common
>perception is that the water filters failed because they were plugged with
>sediments, and that certainly does happen,'' Jordan said. ''But we found
>failures even in Montana where we were filtering water from crystal-clear
>streams all summer. We discovered that the filters' performance degraded
>because we were filtering bacteria into them, and bacteria were growing
>biofilms on the filters. Eventually those biofilms plugged up the filters.
>That's a huge part of filter failure, one that's relatively unknown.'' 
>
>Currently water filter manufacturers are not regulated, and they safety-test
>their own products. Because they don't understand biofilms, their tests may
>not cover the conditions people actually meet in the back country, Jordan
>said. 
>
>For hikers, Jordan recommends these ''best practices.'' To gather water, find
>a spot where you do not disturb the sediment, submerge your closed water
>bottle, open it under the surface, and let water flow in from the middle of
>the water column. Close the bottle underwater and lift it out. That way, you
>start with biofilm-free water, which you can filter for drinking. 
>
>To prevent biofilms from growing on the filter, back-flush the filter every
>few days to wash out the bacteria. Scrubbing the filter's outer element with
>a toothbrush is even more effective. 
>
>Jordan himself doesn't use filters. He relies on chlorine dioxide drops,
>which unlike iodine pills can kill giardia and cryptosporidium even in
>biofilms. (Chlorine dioxide has long been used in municipal water treatment,
>but is a relatively new product for back-country use.) 
>
>Surprisingly, the primary route of intestinal infection on the trail is not
>water, Jordan said, but rather the link between not washing hands after going
>to the bathroom, and handling food. He recommends alcohol hand gels rather
>than soap: ''Soap is too impractical to use properly and alcohol gels kill
>fecal bacteria more effectively.'' 
>
>Back-country dishwashing can become very elaborate, but Jordan has these
>suggestions: Don't wash dishes! Just wipe them clean and dry them out.
>Bacteria can't live long on a dry surface, and putting them in the sun for an
>hour will disinfect them. Boiling water for your next freeze-dried meal will
>sterilize anything that's left in the cooking pot. 
>
>All the more time to lie back and enjoy the stars -- or whatever brought you
>so far from indoor plumbing to begin with.
>
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