October 2006


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Eric Entemann <[log in to unmask]>
Reply To:
Science for the People Discussion List <[log in to unmask]>
Tue, 10 Oct 2006 15:42:21 -0400
text/plain (86 lines)
10 ml of a saturated aqueous iodine solution (at room temperature) in one 
liter of clear stream water (amounting to about 3 parts per million by 
weight of iodine) is supposed to be effective against giardia.  The treated 
water should sit for a half-hour before drinking, longer at low temps.  The 
water definitely has a fairly strong iodine taste.  Perhaps the straw does 
not provide a sufficiently long contact time between the iodine and the 

----Original Message Follows----
From: Michael H Goldhaber <[log in to unmask]>
Reply-To: Science for the People Discussion List              
<[log in to unmask]>
To: [log in to unmask]
Subject: Re: A $3 Water Purifier That Could Save Lives
Date: Tue, 10 Oct 2006 10:21:37 -0700

does the unglazed pot filter viruses?


On Oct 10, 2006, at 8:21 AM, Paddy Apling wrote:

>Of course the simplest water purifier of all in hot countries is an  
>unglazed pot sitting in a "saucer" - drink from the "saucer".
>Much used in desert countries.
>At 14:56 10/10/2006, you wrote:
>>October 10, 2006
>>A $3 Water Purifier That Could Save Lives
>>watch video: < 
>>fr_story=70da9103780eac25e914672c0f66249497c9f93f >
>>In very poor countries, the family that has to walk miles to fetch  
>>drinking water from a well or a stream may be the lucky one. In  many 
>>villages, the water source is a filthy pond trod by animals  and people, 
>>or a mud puddle out next to the yam field.
>>As a result, about 6,000 people a day — most of them children —  die from 
>>water-borne diseases.
>>Vestergaard Frandsen, a Danish textile company that supplies water  
>>filters to the Carter Center guinea worm eradication program and  
>>mosquito-killing plastic tarps to refugee camps, has come up with  a new 
>>invention meant to render dangerous water drinkable.
>>The invention is called Lifestraw, a plastic tube with seven  filters: 
>>graduated meshes with holes as fine as 6 microns (a human  hair is 50 to 
>>100 microns), followed by resin impregnated with  iodine and another of 
>>activated carbon. It can be worn around the  neck and lasts a year.
>>Lifestraw isn’t perfect, but it filters out at least 99.99 percent  of 
>>many parasites and bacteria, the demons in most fatal cases of  diarrhea.
>>It is less effective against viruses, which are much smaller and  cause 
>>diseases like polio and hepatitis, and it wouldn’t protect  American 
>>backpackers against the parasite giardia.
>>Nor does it filter out metals like arsenic, and it has a slight  iodine 
>>aftertaste (not necessarily a bad thing in the large  stretches of the 
>>globe with iodine deficiency).
>>It can be manufactured for about $3, but it needs more field- testing. 
>>Only about 100,000 have been handed out, 70,000 to  earthquake victims in 
>>Kashmir last year.
>>Already in the works, however, is a Lifestraw toddler version —  which 
>>will be squeezable.
>>Copyright 2006 The New York Times Company
>>s. e. anderson (author of "The Black Holocaust for Beginners" -  Writers + 
>>Readers) +