What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

On Aug 8, 2:31*pm, wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

A good household water filter takes care of that. What idiots dont
know about water leads them to buy bottled water, you can make better
out of tap, which is what alot use to make bottled. You are first off
panicking, second misinformed. 3rd over concerned x 10. I use a simple
filter used by mc Donalds, the army, airlines, etc etc but I forgot
its name because its not relavent in my life. Shacklee makes a great
table unit, but you really need to learn and not panic. what people
are getting sick from is Mexican fields , chillies, from field and
sewage treatment plant flood runoffs. I was In mexico in Mechicuan
Cotija, the sewage plant was in the valley with the crops, in the
monsoon season it overflowed, do you need any more explanation. They
got sick and did not know why. Instead Go buy a iphone and dont worry

Steve,

There are effective UV water purifiers. These don't work on lead. I
thought fluride was good thing. There are companies that will do fairly good
water testing. Perhaps you should figure out if you have a problem before
you look for a cure.
Sorry, I have no opinion on bottled water.

Dave M

wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.

'cause he's a dickhead. that's why i plonked him over 6 months ago.

s


"Anthony Diodati" mrbreezeet1NO wrote in message
...

"ransley" wrote in message
...
On Aug 8, 2:31 pm, wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

"What idiots don't
know about water leads them to buy bottled water"

How come you always seem to come off so mean?
Tony

wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.



Hmmm,
I installed under the sink 6 stage filtering unit. Last stage is UV
light tube. According to my sister and brother(both chemists, brother
works for city water demartment) The filtered water is at least 99%
pure. It produces enough water per day for drinking and cooking.
Best thing is it does not have chlorine smell or funny taste. Even our
dog and cats drink that water.

ransley wrote:
On Aug 8, 2:31 pm, wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

A good household water filter takes care of that. What idiots dont
know about water leads them to buy bottled water, you can make better
out of tap, which is what alot use to make bottled. You are first off
panicking, second misinformed. 3rd over concerned x 10. I use a simple
filter used by mc Donalds, the army, airlines, etc etc but I forgot
its name because its not relavent in my life. Shacklee makes a great
table unit, but you really need to learn and not panic. what people
are getting sick from is Mexican fields , chillies, from field and
sewage treatment plant flood runoffs. I was In mexico in Mechicuan
Cotija, the sewage plant was in the valley with the crops, in the
monsoon season it overflowed, do you need any more explanation. They
got sick and did not know why. Instead Go buy a iphone and dont worry
Hi,
Filtering is good but to be effective it has to be maintained properly.

HeyBub wrote:
wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.


Hmmm,
Plastic bottle? I wouldn't. I'd with glass bottle.

"ransley" wrote in message
...
On Aug 8, 2:31 pm, wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

"What idiots don't
know about water leads them to buy bottled water"

How come you always seem to come off so mean?
Tony

On Fri, 8 Aug 2008 12:31:43 -0700 (PDT), wrote:

What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.



It is true that UV will kill bacteria, but obviously depends on the
strength and duration of the exposure. UV kills human skin cells too,
and hopefully the skin repairs itself quickly without growing cancer
cells.

The absolute cleanest water is distilled water that has been
de-gassed. It doesn't taste too good and not practical for drinking,
but it is as pure as it gets. Possibly drinking bottled water has
higher risks than drinking tap water. A good compromise is using a
canister pitcher with filter, such as a Britta. I think it makes
better tasting tea/coffee.

Don't be too germ phobic. I heard a dog's mouth is much cleaner
than a human's mouth and people don't even lick their own butt.

Tony Hwang wrote:

Right. You can put almost any (relatively clear) water in a clear
plastic bottle, put the bottle in the sun for a few hours, and,
presto, sterilized water.


Hmmm,
Plastic bottle? I wouldn't. I'd with glass bottle.

I agree. But with 14,000,000 plastic bottles being produced each day, what
are the chances?

On Sat, 09 Aug 2008 08:09:41 -0400, Phisherman
wrote Re UV for killing bacteria in water:

Don't be too germ phobic. I heard a dog's mouth is much cleaner
than a human's mouth and people don't even lick their own butt.

True, however many employed people lick their boss's butts. That's
really disgusting.

On Aug 8, 4:33*pm, "David L. Martel" wrote:
Steve,

* * There are effective UV water purifiers.

I buy a UV light and stick it to my 1 gallon filter tank, how
efficient will it be in killing bacteria?

These don't work on lead.
I know.

I
thought fluride was good thing.

Why? I have both a high floride level and bacteria counts.

There are companies that will do fairly good
water testing. Perhaps you should figure out if you have a problem before
you look for a cure.

I've tested my tap water. 90% of harmful stuff isn't present. Problem
is 10% is present.

On Aug 8, 5:35*pm, "HeyBub" wrote:

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.

How effective? What % of bacteria will simple sunlight kill in a few
hours? Thanks for the tip. I'll try that and retest it if you don't
respond and hopefully post the results here.

On Aug 8, 7:39*pm, Tony Hwang wrote:
Hmmm,
I installed under the sink 6 stage filtering unit.

Wow can you elaborate? TIA.

Last stage is UV
light tube. According to my sister and brother(both chemists, brother
works for city water demartment) The filtered water is at least 99%
pure. It produces enough water per day for drinking and cooking.
Best thing is it does not have chlorine smell or funny taste. Even our
dog and cats drink that water.

Where you find your UV light? TIA.
99% ? Shouldn't you expect something like 99.9999%?
Provided the end water is "pure" the less chlorine the better
definitely.

On Aug 9, 5:09*am, Phisherman wrote:
On Fri, 8 Aug 2008 12:31:43 -0700 (PDT), wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

It is true that UV will kill bacteria, but obviously depends on the
strength and duration of the exposure. *UV kills human skin cells too,
and hopefully the skin repairs itself quickly without growing cancer
cells.

The absolute cleanest water is distilled water that has been
de-gassed. *It doesn't taste too good and not practical for drinking,
but it is as pure as it gets. *Possibly drinking bottled water has
higher risks than drinking tap water. *A good compromise is using a
canister pitcher with filter, such as a Britta. * I think it makes
better tasting tea/coffee.

Don't be too germ phobic. * *I heard a dog's mouth is much cleaner
than a human's mouth and people don't even lick their own butt.

Bacteria is only part of the problem. There's poisons too. And the
potential is high since there's miles of various pipes leading to your
tap. Furthermore, the less harmful bacteria in us, the better. Problem
is with bacteria, it is impossible to avoid completely. Worse is when
you detox which harms our good bacteria. Some things we have to live
with at the time being.

wrote:
On Aug 8, 7:39 pm, Tony Hwang wrote:
Hmmm,
I installed under the sink 6 stage filtering unit.

Wow can you elaborate? TIA.

Last stage is UV
light tube. According to my sister and brother(both chemists, brother
works for city water demartment) The filtered water is at least 99%
pure. It produces enough water per day for drinking and cooking.
Best thing is it does not have chlorine smell or funny taste. Even our
dog and cats drink that water.

Where you find your UV light? TIA.
99% ? Shouldn't you expect something like 99.9999%?
Provided the end water is "pure" the less chlorine the better
definitely.
Hi,
It came with the filter kit. I am sure you can find them at electrical
supply house.
It is a long cylindrical shape running on low voltage thru wall wart. I
think the main component is RO cartridge. Now kettle stays clean. No
scale build up. Our tap water is safe to drink(I trust my own bro, LOL)
but it's hard water, flouride, chlorine added which I don't like.
That 99% is conservative figure. Also as a side note we use rain water
for our plants. We have barrels round the house collecting rain water.

Steve,


There are effective UV water purifiers.

I buy a UV light and stick it to my 1 gallon filter tank, how
efficient will it be in killing bacteria?

Consult with a pro since you already have your lab results. I can not
tell you that some unknown light bulb will generate enough energy at the
proper frequency to kill the bacteria nor do I know how long it would take
to sterilize a gallon of water.
You sound as if you want to do this yourself. I'd recommend heading to
the library if there is a good one nearby or get help from the ag extension
folks. Remember that the UV light may damage the filter tank if you are not
careful and it will not be safe for humans.



I've tested my tap water. 90% of harmful stuff isn't present. Problem
is 10% is present.

Take your lab results to a water conditioning company or two and see what
they recommend to correct your water. If it's really expensive or you don't
own the home use bottled water for drinking and cooking.

Dave M.

wrote:
On Aug 8, 5:35 pm, "HeyBub" wrote:

Right. You can put almost any (relatively clear) water in a clear
plastic bottle, put the bottle in the sun for a few hours, and,
presto, sterilized water.

How effective? What % of bacteria will simple sunlight kill in a few
hours? Thanks for the tip. I'll try that and retest it if you don't
respond and hopefully post the results here.

There's bags of studies on this concept. Here's one:

http://www.icross.ie/publications/pd...nfection_1.pdf

"In-vitro studies carried out at the Royal College of Surgeons in Ireland
confirmed the bactericidal effect of solar radiation and showed that
transparent plastic bottles allow passage of more ultraviolet light than do
transparent glass bottles. Although glass transmits ultraviolet light more
readily, the thinness of plastic bottles compensates for plastic's greater
absorption of ultraviolet light. This finding suggested that non-returnable
plastic bottles, which are widely available and even a source of pollution,
may be used for the disinfection of drinking water."

The authors consider this experiment utilizing little brown babies in Kenya
as a follow-up to an earlier study that relied on the heating effect of
sunlight for disinfection.

wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

For bacteria and flouride, go with an RO filter system. You can buy them
at Costco for about $150.

UV light does kill bacteria but there's no need to use UV on municipal
water. The big advantage of UV is that it kills viruses that are too
small to be filtered out. They're useful if you're drinking water in
foreign countries, or in some back-country applications (i.e. there was
a warning by one river in Yellowstone about viruses in the water). Back
country filters don't kill viruses, but you can get a UV Steripen for
that purpose.

Wow! Thanks for all the input!! UV Steripen huh? I'll do a little
googling on that. Thanks.

David L. Martel wrote:
Steve,

There are effective UV water purifiers. These don't work on lead. I
thought fluride was good thing. There are companies that will do fairly good
water testing. Perhaps you should figure out if you have a problem before
you look for a cure.
Sorry, I have no opinion on bottled water.

Dave M


I know of no universal solutions. UV sterilizers are useful, I use one
to process all of my water as it comes from my well, but you first need
to understand it's limitations. Look at the energy/unit area required
to kill various organisms

http://www.r-can.com/download.php?file_id=359

Some are quite resistant, many organisms aren't listed here also.

A key issue is maintenance. The internal surfaces through which UV
energy must pass must be kept clean. The water must be clear too. Some
water, due to particulate matter has a very high extinction coefficient.

I doubt the effectiveness of small, under counter, UV sterilizers at
anything but the very lowest flow rates.

As to materials, UV is attenuated by many glasses, plastic may be
better, but will likely be damaged by UV. Quartz is best.

On Aug 10, 8:06*am, Boden wrote:
David L. Martel wrote:
Steve,

* * There are effective UV water purifiers. These don't work on lead. I
thought fluride was good thing. There are companies that will do fairly good
water testing. Perhaps you should figure out if you have a problem before
you look for a cure.
* *Sorry, I have no opinion on bottled water.

Dave M

I know of no universal solutions. *UV sterilizers are useful, I use one
to process all of my water as it comes from my well, but you first need
to understand it's limitations. *Look at the energy/unit area required
to kill various organisms

http://www.r-can.com/download.php?file_id=359

Some are quite resistant, many organisms aren't listed here also.

A key issue is maintenance. *The internal surfaces through which UV
energy must pass must be kept clean. *The water must be clear too. *Some
water, due to particulate matter has a very high extinction coefficient.

I doubt the effectiveness of small, under counter, UV sterilizers at
anything but the very lowest flow rates.

As to materials, UV is attenuated by many glasses, plastic may be
better, but will likely be damaged by UV. *Quartz is best.

I'm thinking about strapping a small UV light to my water filter
reservoir, about a gallon big. That should do it. Doubt UV light will
harm the plastic aside from the
heat of the bulb.
Thanks.

wrote in message
...
On Aug 10, 8:06 am, Boden wrote:
David L. Martel wrote:
Steve,

There are effective UV water purifiers. These don't work on lead. I
thought fluride was good thing. There are companies that will do fairly
good
water testing. Perhaps you should figure out if you have a problem
before
you look for a cure.
Sorry, I have no opinion on bottled water.

Dave M

I know of no universal solutions. UV sterilizers are useful, I use one
to process all of my water as it comes from my well, but you first need
to understand it's limitations. Look at the energy/unit area required
to kill various organisms

http://www.r-can.com/download.php?file_id=359

Some are quite resistant, many organisms aren't listed here also.

A key issue is maintenance. The internal surfaces through which UV
energy must pass must be kept clean. The water must be clear too. Some
water, due to particulate matter has a very high extinction coefficient.

I doubt the effectiveness of small, under counter, UV sterilizers at
anything but the very lowest flow rates.

As to materials, UV is attenuated by many glasses, plastic may be
better, but will likely be damaged by UV. Quartz is best.

I'm thinking about strapping a small UV light to my water filter
reservoir, about a gallon big. That should do it. Doubt UV light will
harm the plastic aside from the
heat of the bulb.
Thanks.

Blattt! Wrong answer! LOL! Sorry, I thought that it would be a hoot.
Anyway, UV light has damaging effects on nearly all plastics. Just think to
the things that you've noticed had cracked or faded. I don't believe it
will happen tomorrow but it will happen over time. There might be a site
around which will assist with an estimate but there are a lot of variables
at work. If the resevoir is inexpensive and easy to find you can go for it
and see if it fails in the next couple of years.

"HeyBub" wrote in message
m...
wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.

A less desireable 'presto' is outgassing of the plastic. Haven't you
noticed the taste of water left in the car for a couple of days?

In article ,
"C & E" wrote:

"HeyBub" wrote in message
m...
wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.

A less desireable 'presto' is outgassing of the plastic. Haven't you
noticed the taste of water left in the car for a couple of days?

That taste is called rotting backwash.

In article , HeyBub wrote:
wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.

Except that the main germicidal wavelngths of UV (UVC of wavelength
around 240-280 nm) are highly blocked by the ozone layer even when the
ozone layer is weakened, and these wavelengths also have a high rate of
being blocked by plastics that are transparent when thick enough to make
bottles from such plastics.

- Don Klipstein )

In article hu7nk.65714$nD.55685@pd7urf1no, Tony Hwang wrote:
HeyBub wrote:
wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.

Hmmm,
Plastic bottle? I wouldn't. I'd with glass bottle.

The glass used for making bottles also blocks UVC and even most UVB.

Then again, I have doubt about sterilizing water with a light source
that does not exterminate plankton in shallow ponds.

- Don Klipstein )

Don Klipstein wrote:

Right. You can put almost any (relatively clear) water in a clear
plastic bottle, put the bottle in the sun for a few hours, and,
presto, sterilized water.

Except that the main germicidal wavelngths of UV (UVC of wavelength
around 240-280 nm) are highly blocked by the ozone layer even when the
ozone layer is weakened, and these wavelengths also have a high rate
of being blocked by plastics that are transparent when thick enough
to make bottles from such plastics.

The blockage may be high, but the resulting radiation is sufficient. At
least according to all the studies I've been able to find.

On Aug 10, 4:38*pm, "C & E" wrote:

Blattt! *Wrong answer! LOL! *Sorry, I thought that it would be a hoot..
Anyway, UV light has damaging effects on nearly all plastics.

So does mere age accomplish the same thing to all material, a little
UV just speeds the damage to some minute degree. Does that mean never
buy water sold in clear plastic bottles? No. Sunlight comes through
our kitchen for several hours every day for years and nothing plastic
has noticeably cracked or deformed. Relax.

*Just think to
the things that you've noticed had cracked or faded.
Yeah time will do this to everything. The faded part is UV induced but
so what?

Don't believe it
will happen tomorrow but it will happen over time.

Bingo.
*There might be a site
around which will assist with an estimate but there are a lot of variables
at work. *If the resevoir is inexpensive and easy to find you can go for it
and see if it fails in the next couple of years.- Hide quoted text -

Nothing will fail in a couple years. Couple decades and it will be
mainly due to age.

On Aug 10, 4:40*pm, "C & E" wrote:

A less desireable 'presto' is outgassing of the plastic. *Haven't you
noticed the taste of water left in the car for a couple of days?

Yeah and mere heat was the big culprit. Do you know how hot it gets in
cars?

On Aug 10, 5:23*pm, (Don Klipstein) wrote:
* Except that the main germicidal wavelngths of UV (UVC of wavelength
around 240-280 nm) are highly blocked by the ozone layer

What about UV lights? Do they have the desirable germicidal effect?
Thanks.

On Aug 10, 6:10*pm, "HeyBub" wrote:
Don Klipstein wrote:
Right. You can put almost any (relatively clear) water in a clear
plastic bottle, put the bottle in the sun for a few hours, and,
presto, sterilized water.

*Except that the main germicidal wavelngths of UV (UVC of wavelength
around 240-280 nm) are highly blocked by the ozone layer even when the
ozone layer is weakened, and these wavelengths also have a high rate
of being blocked by plastics that are transparent when thick enough
to make bottles from such plastics.

The blockage may be high, but the resulting radiation is sufficient. At
least according to all the studies I've been able to find.

Just buying a UV light and be done with it. I'm lazy.

In ,
wrote:

On Aug 10, 6:10*pm, "HeyBub" wrote:
Don Klipstein wrote:
Right. You can put almost any (relatively clear) water in a clear
plastic bottle, put the bottle in the sun for a few hours, and,
presto, sterilized water.

*Except that the main germicidal wavelngths of UV (UVC of wavelength
around 240-280 nm) are highly blocked by the ozone layer even when the
ozone layer is weakened, and these wavelengths also have a high rate
of being blocked by plastics that are transparent when thick enough
to make bottles from such plastics.

The blockage may be high, but the resulting radiation is sufficient. At
least according to all the studies I've been able to find.

Just buying a UV light and be done with it. I'm lazy.

I just hope you don't rely on germicidal effects from those "blacklights"
whose UV is mainly in the longwave roughly-60% of the UVA range - which
does not even cause much suntanning of human skin. (At higher intensities,
such longwave UV wavelengths still have ill effects on a couple parts of
the human eye and some organic pigments/dyes.)

Killing bacteria with UV depends highly on sufficient exposure to UV
wavelengths that are in or very near the UVC range.
The main germicidal UV wavelength from "germicidal UV lamps" is 253.7
nm, AKA 254 nm, from low pressure mercury vapor combined with an inert
gas, usually argon, sometimes krypton, sometimes neon, sometimes a mixture
of argon with either neon or krypton.

- Don Klipstein )

In ,
wrote:

On Aug 10, 5:23*pm, (Don Klipstein) wrote:
* Except that the main germicidal wavelngths of UV (UVC of wavelength
around 240-280 nm) are highly blocked by the ozone layer

What about UV lights? Do they have the desirable germicidal effect?

That depends on what the UV lights are. There are a few varieties of
UV!

Longer wave 65% or so of UVA, 340 to 400 nm or so: This is the
"blacklight range", as in the main wavelength range for dim violetish
color lamps to cause organic fluorescent substances to glow.

This wavelength range has its "traditional base" being the 365-366 nm
cluster of wavelengths of high pressure mercury vapor lamps. Blacklight
"fluorescent lamps" (those are actually true fluorescent lamps) of BL and
BLB types have a phosphor that absorbs the 254 and 185 nm main wavelengths
from glowing low pressure mercury vapor to produce fluorescence in
longer-wave UV around 360 nm.

There are many UV LEDs with peak wavelength around 395 nm, and fewer
with shorter wavelengths but still mostly at least 350 nm. When an LED
has nominal peak wavelength 350-375 nm, it tends to dimly visibly glow
with a violetsh-white color - due to weak out-of-main-band spectral
content combined with the visible-violet-fringe of the main UVA emission
band.
When a UV or "near-UV" or "nearly-UV" LED has peak wavelength in the
380 to 410 nm range, especially of 395 or 400 or 405 nm common
wavelengths, such an LED is typically quite violetish in color and often
not especially dim. 400 nm is the "official border" between UVA and
"visible light", LEDs with peak wavelength slightly below 400 nm have
their main emission bands having some significant spectral content at
wavelengths above 400 nm, and "near-UV" of wavelengths only slightly
shorter than 400 nm is dimly visible.

The main human health hazards from longer-UVA wavelengths a

* To the lens of the eye (mainly impacting farm hands and long-haul truck
drivers working heavily within roughly 35 degrees latitude from the
equator).

* To the retina of the eye, mainly from focused intense images of strong
sources of such UV such as staring into a UV LED.

Next shorter wavelength significat subdivision of UV: Tanning UVA.
That is roughly 315-340 nm.
Keep in mind that "tanning UVA" is not completely harmless to human
skin, and can also be harsh on the retina, lens and cornea of the human
eye.

Next after that is UVB - 280 to 315 nm. That is a harsher range of UV.
UVB content in sunlight reaching Earth's surface is mostly 300-315 nm.

Ill effects to the human eye from shorter wavelengths of UV tend to be
more concentrated to more-foreward parts of the human eye. UVB has some
prospect to do bad things to the lens of the human eye, but is worst to
the cornea.
UVB is notably harsh on human skin and blamed for many skin cancers,
especially ones of the more-malignant class of "malignant melanomas".

Next down in UV categorization by wavelength is non-vacuum portion of
UVC. That is 200-280 nm. "Germicidal UV" is mainly the longwave 50-60%
or so of this range, and the shortest UVB wavelengths are indeed are
slightly to somewhat germicidal. The 254 / 253.7 nm wavelength from low
pressure mercury vapor (combined appropriately with a "noble gas" or a
mixture of "noble gases") is the main wavelength for such purpose from
lamps made for such purpose.

The main human health hazards from UV wavelengths that short are to the
conjunctiva and outer regions of the cornea of the eye, and to the
epidermis of the skin. Carcinogenesis to human skin from UVC appears to
be a significant problem from significant exposure, and appears to be
likely confined to the epidermis - where the more malignant skin cancers
of "malignant melanoma" type tend to originate.
Just to point out an alarmist thing to watch for - there is such a
thing as non-melanin-producing malignant melanoma. That is an uncommon
but deadly known "subvariant" skin cancer whose critical early warning
sign is otherwise-unexplained growth of a reddish area on the skin,
mole-like small or almost that small in size when it is in an earlier
stage when having a dermatologist removing it has a good chance of saving
your life from removing such a deadly cancer at such a sufficiently early
stage.

UV wavelengths in the UVC range also include the 10 to 200 nm range as
well as the 200-280 nm range. The sub-200-nm wavelength range is "vacuum
ultraviolet" "AKA VUV", absorbed by air and oproducing ozone in the a
process. Few transparant solid materials pass significantly even a part
of this wavelength range.
The main wavelength of low pressure mercury vapor in this range is 184.9
AKA 185 nm.

- Don Klipstein )

"HeyBub" wrote in message
m...
wrote:
What's the cleanest (from the harmful crap like bacteria/lead/etc)
bottled water anyone? Bay area tap water has high counts of bacteria &
floride. And is it true a simple UV light will kill 99.9% of bacteria
in water? TIA.

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.
And the proof of that is that dogs don't get sick after drinking from
puddles!
I sure hope nobody follows that advice, cause we aren't dogs.

On Aug 10, 8:24*pm, (Don Klipstein) wrote:
In ,

wrote:
On Aug 10, 5:23*pm, (Don Klipstein) wrote:
* Except that the main germicidal wavelngths of UV (UVC of wavelength
around 240-280 nm) are highly blocked by the ozone layer

What about UV lights? Do they have the desirable germicidal effect?

* That depends on what the UV lights are. *There are a few varieties of
UV!

* Longer wave 65% or so of UVA, 340 to 400 nm or so: *This is the
"blacklight range", as in the main wavelength range for dim violetish
color lamps to cause organic fluorescent substances to glow.

* This wavelength range has its "traditional base" being the 365-366 nm
cluster of wavelengths of high pressure mercury vapor lamps. *Blacklight
"fluorescent lamps" (those are actually true fluorescent lamps) of BL and
BLB types have a phosphor that absorbs the 254 and 185 nm main wavelengths
from glowing low pressure mercury vapor to produce fluorescence in
longer-wave UV around 360 nm.

* There are many UV LEDs with peak wavelength around 395 nm, and fewer
with shorter wavelengths but still mostly at least 350 nm. *When an LED
has nominal peak wavelength 350-375 nm, it tends to dimly visibly glow
with a violetsh-white color - due to weak out-of-main-band spectral
content combined with the visible-violet-fringe of the main UVA emission
band.
* When a UV or "near-UV" or "nearly-UV" LED has peak wavelength in the
380 to 410 nm range, especially of 395 or 400 or 405 nm common
wavelengths, such an LED is typically quite violetish in color and often
not especially dim. *400 nm is the "official border" between UVA and
"visible light", LEDs with peak wavelength slightly below 400 nm have
their main emission bands having some significant spectral content at
wavelengths above 400 nm, and "near-UV" of wavelengths only slightly
shorter than 400 nm is dimly visible.

* The main human health hazards from longer-UVA wavelengths a

* *To the lens of the eye (mainly impacting farm hands and long-haul truck
* drivers working heavily within roughly 35 degrees latitude from the
* equator).

* *To the retina of the eye, mainly from focused intense images of strong
sources of such UV such as staring into a UV LED.

* Next shorter wavelength significat subdivision of UV: *Tanning UVA.
That is roughly 315-340 nm.
* Keep in mind that "tanning UVA" is not completely harmless to human
skin, and can also be harsh on the retina, lens and cornea of the human
eye.

* Next after that is UVB - 280 to 315 nm. *That is a harsher range of UV.
UVB content in sunlight reaching Earth's surface is mostly 300-315 nm.

* Ill effects to the human eye from shorter wavelengths of UV tend to be
more concentrated to more-foreward parts of the human eye. *UVB has some
prospect to do bad things to the lens of the human eye, but is worst to
the cornea.
* UVB is notably harsh on human skin and blamed for many skin cancers,
especially ones of the more-malignant class of "malignant melanomas".

* Next down in UV categorization by wavelength is non-vacuum portion of
UVC. *That is 200-280 nm. *"Germicidal UV" is mainly the longwave 50-60%
or so of this range, and the shortest UVB wavelengths are indeed are
slightly to somewhat germicidal. *The 254 / 253.7 nm wavelength from low
pressure mercury vapor (combined appropriately with a "noble gas" or a
mixture of "noble gases") is the main wavelength for such purpose from
lamps made for such purpose.

* The main human health hazards from UV wavelengths that short are to the
conjunctiva and outer regions of the cornea of the eye, and to the
epidermis of the skin. *Carcinogenesis to human skin from UVC appears to
be a significant problem from significant exposure, and appears to be
likely confined to the epidermis - where the more malignant skin cancers
of "malignant melanoma" type tend to originate.
* Just to point out an alarmist thing to watch for - there is such a
thing as non-melanin-producing malignant melanoma. *That is an uncommon
but deadly known "subvariant" skin cancer whose critical early warning
sign is otherwise-unexplained growth of a reddish area on the skin,
mole-like small or almost that small in size when it is in an earlier
stage when having a dermatologist removing it has a good chance of saving
your life from removing such a deadly cancer at such a sufficiently early
stage.

* UV wavelengths in the UVC range also include the 10 to 200 nm range as
well as the 200-280 nm range. *The sub-200-nm wavelength range is "vacuum
ultraviolet" "AKA VUV", absorbed by air and oproducing ozone in the a
process. *Few transparant solid materials pass significantly even a part
of this wavelength range.
* The main wavelength of low pressure mercury vapor in this range is 184.9
AKA 185 nm.

*- Don Klipstein )

Skin cancer is over blown. No one ever died from it. Lots of people
who've spent most of their lives outdoors live to be over 100. Get out
more. Furthermore I ain't gonna be sunbathing by my water tank. So
skin exposure isn't even an issue, nor eye problems. I'll black it out
from view if it get annoying.
.. off to get me some UV.

On Aug 10, 9:27*pm, "jack" wrote:

Right. You can put almost any (relatively clear) water in a clear plastic
bottle, put the bottle in the sun for a few hours, and, presto, sterilized
water.

And the proof of that is that dogs don't get sick after drinking from
puddles!
I sure hope nobody follows that advice, cause we aren't dogs.

Where did he say bottled puddle water? Your logic escapes me.

wrote:

The blockage may be high, but the resulting radiation is sufficient.
At least according to all the studies I've been able to find.

Just buying a UV light and be done with it. I'm lazy.

Right. But an 80-mile long extension cord is out of the question for the
little brown babies in remote regions of Kenya.

Maybe a battery-operated one?

jack wrote:

Right. You can put almost any (relatively clear) water in a clear
plastic bottle, put the bottle in the sun for a few hours, and,
presto, sterilized water.
And the proof of that is that dogs don't get sick after drinking from
puddles!
I sure hope nobody follows that advice, cause we aren't dogs.

Right. A Dog's digestive system relies on a different mix of chemicals than
a human's. This different mix (I think it's fuming Nitric Acid), kills
almost everything. That which is still active, is barfed up and the dog
re-eats around the offending material.