RE: [at-l] Steri-Pen How Ultraviolet Light Disinfects (http://www .hydro-photon.com/hydropg

["McBride, James" <mcbride_j@lxe.com>]

I have not gone to the web site to check it out, but it appears you are
talking about a small handheld unit that is supposed to purify water by
ultraviolet light (UV) generated from a single 9v battery.

	Sorry but this is just not possible.

	Given that UV can purify water (and I don't know this to be true),
there is absolutely no way that a handheld unit with a single 9v battery
could put out the amount of UV necessary to do the job. This little unit
would have to have a significantly higher power density in the UV range
(power per square meter, Watts/meter^2)  than sunlight. This is extremely
doubtful. If it can do this then watch out and don't point it at anyone
unles you want to give them an instant and severe sunburn!

	Jim McBride




> ----------
> From: 	W F Thorneloe, MD[SMTP:thornel@ibm.net]
> Sent: 	Monday, July 26, 1999 3:04 PM
> To: 	David  F. Addleton
> Cc: 	AT-L
> Subject: 	Re: [at-l] Steri-Pen How Ultraviolet Light Disinfects
> (http://www.hydro-photon.com/hydropg
> 
> I think part of your experience was based with the fact that Himalyan 
> mountain water would be clearer and less contaminated from critters or 
> people. Turbid water would contain far more organic material, as it
> tumbles 
> downstream.
> 
> UV has a role, at least in reducing air born contaminants falling into 
> water prepared for public consumption. I just have doubt that a 9V battery
> 
> and a glowing light would do much with real water contaminants, especially
> 
> with fecal or Giardia exposure. Testing would be fairly straight forward 
> and direct, and easily replicated by independent labs. I would expect to 
> see such studies from any number of University labs, forensic labs, or NIH
> 
> facilities. Something smells regarding the amount of time these folks have
> 
> been advertising this product that should be available "real soon now." 
> Sounds a lot like product announcements from Micro$oft that never quite 
> make it on time.
> 
> OrangeBug
> Atlanta, GA
> 
> 
> At 12:13 PM 7/26/1999 -0400, David  F. Addleton wrote:
> >Have you got any idea where this info may have come from? Is there any
> >reference source for this data?
> >I'm interested in the rationale for your suspicion, since I've had the
> long
> >held belief in the efficacy of uv light to destroy harmful
> microorganisms.
> >And I can't pinpoint the source of the belief, since it comes from way
> way
> >back in childhood ... one of those stories put in my brain as a kid ...
> >David
> 
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> 
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