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Re: Purifying Water

-- [ From: Joe O'Neill * EMC.Ver #2.10P ] --

> Do water purification tablets work as effectively as a filter system 
> (such as Sweetwater)? 
> I can see myself filling up my water bottle mid day and dropping a
> tablets in it and then continue walking while the stuff purifies - it
> seems faster than a filter and I can save the use of the filter (and
> life of the cartridge) for at camp...Is this a common practice and/or
> good idea as far as having healthy water goes?


Thought you might be interested in a query/response I found on a


To: ALL 

Time: 01/20    10:16 PM

I recently saw a program, Popular Mechanics, a weekly show. 
 They interviewed an AT thru hiker about his experience and 
the equipment that he used.  When asked about water         
purification he pulled out a bandana and a bottle with a    
medicine dropper containing clorine.  He indicated to the   
show's host that that is what he used for his entire trip.  
I was wondering how effective his simple treatment system   
would really be.  I'm no chemist and was wondering  if his  
system really was safe and effective.                       

PRODIGY(R) interactive personal service - Date: 02/14 Time:  7:53


Time: 02/12    11:37 PM

   Hi, Bruce:  Chlorine works, up to a point.  That is, what
it does kill, it kills quickly and effectively.  It's what  
it doesn't kill---most notably Giardia---that is worrisome. 
     Iodine kills a wider variety of microorganisms than    
chlorine, and is therefore more widely recommended and used.
However, iodine has its problems.  The lower the temperature
and oxygen content of the water, the greater the dosages and
standing times before drinking are required.  Where         
available water is primarily composed of snowmelt (only a   
few degrees above freezing), it is recommended that you     
double both the dosage and standing time.  In practical     
terms, this means that, among other factors, you'll have a  
wait of anywhere from a half-hour to an hour before being   
able to drink the treated water.                            
     Neither chlorine or iodine does anything about         
particulate matter in the water (silt, algae, etc.), hence  
the bandana.  Drinking said particulates is usually more    
unpleasant than it is dangerous, but I suspect most of us   
would not willingly consume them, given any choice in the   
     Iodine can accumulate in the body (notably the thyroid)
and cause problems---yellowing of the skin being the least  
of them.  Generally speaking, it is not recommended that one
rely upon iodine for water purification for more than a week
and a half (two weeks, according to some, more generous,    
estimates).  Planning a thru-hike of the AT in that period  
of time might be most charitably described as unrealistic.  
<G>  People with thyroid problems, and pregnant women, are  
advised to steer clear of iodine altogether.                
     Secondary treatment of iodine, such as is available    
with Potable Aqua, will neutralize the iodine and kill its  
unpleasant taste, which helps offset some of the above      
objections.  On the other hand it involves one more extra   
step and another bottle of tablets to keep track of.  The   
secondary treatment, BTW, is nothing more exotic than citric
acid, or good old vitamin C.     >>>MORE>>>>                
     Mechanical purifiers, such as the Pur Explorer and     
Scout models, which use a iodine system do leave trace      
amounts of iodine in the water, and carry the appropriate   
cautions in their instruction manuals.  Most such models,   
however, do offer an optional carbon cartridge which can be 
attached over the outlet to neutralize the iodine.  At a    
greater cost in weight, bulk, and price, of course.  Iodine,
BTW, is the only treatment that will protect against        
viruses, which is something to consider when Third World    
travel is on the agenda.                                    
     Hope this helps.  Happy trails.                        
                                       N & N, Karl          

PRODIGY(R) interactive personal service - Date: 02/14 Time:  7:54 AM

Joe O'Neill
Shamrock '95-'00