RE: [Paddlewise] water treatment

>From: Joe Brzoza <joebr_at_burton.com>

>Yikes!  Can people really rely on those iodine pills for safe drinking
>water?  I may be over paranoid but I only rely on a filter - and only like
>using that for emergencies.  I figure with all those tubes dangling from 
>the
>filter something is going to get infected.  Then again I have done 
>multi-day
>trips relying on the filter for my entire water supply without a problem.
>
>My filter reliance was recently reinforced when a co-worker returned from
>traveling in South America with a case of Hepatitis (sp?).  It seems he had
>only been using the pills to treat his water.  His SO, however did not
>contract any bad bugs during their trip - so I'm sure there were many other
>variables involved.
>
>Your choice - but I'm being careful.  Heck maybe I should treat the 
>filtered
>water with the pills to be extra safe?
Hi Joe,
I work as a writer for an outdoor retailer - however I mention this only so 
you know I have some small idea of what I am talking about, not because I am 
trying to sell you any particular unit or have you purchase from my 
employer.

Filters, in the strict sense of physical filters that actually strain out 
pathogens, come in a variety of types and sizes, from fairly coarse and 
cheap units that are intended to stop only protozoa such as Cryptosporidium 
("beaver fever") to more expensive and finer pore-sized filters which can 
stop bacteria as well. In practise, these finer filters often provide a 
certain amount of protection against viruses as well, since though the 
viruses are more than small enough to slip through the pores, they are often 
stuck to larger particulate matter in the water. However, this is not 
guaranteed, so if viruses are suspected, you should use chemicals (iodine or 
bleach)  as well as a filter. The disadvantage of using chemicals alone 
(without a filter) is that chemicals are affected by water temperature and 
turbidity, and also may not kill Cryptosporidium and other protozoa in their 
cyst forms.
There are a number of commercial units which combine physical filters with 
an iodine element to stop protozoa, bacteria, and viruses. Such combination 
units are technically called "purifiers" and must be certified by the US EPA 
to be sold as such (chemicals and plain filters do not need to be approved 
by the EPA).
Hope this is of some help.

Philip Torrens
N49°16' W123°06'

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