View Full Version : UV Light may not be as effective as once thought
http://www.the-scientist.com/?articles.view/articleNo/42009/title/UV-Light-Doesn-t-Fully-Purify/
perdidochas
01-30-2015, 16:03
http://www.the-scientist.com/?articles.view/articleNo/42009/title/UV-Light-Doesn-t-Fully-Purify/
Not a real surprise to me.
Old Hiker
01-30-2015, 23:56
Lots of "may" and "may not" as well as "leaving chance" and "suggesting".
This is why I carry the 1 pound filter AND the chlorine tabs with neutralizers with the germ-x and soap sheets. I'd rather be safe than sorry.
Still, I hope they continue the research to get a definite answer.
Tuckahoe
01-31-2015, 07:20
Science uses qualifiers and if a similar study of filter and tabs were conducted, it would contain the very same qualifiers. Only in poorly written newspaper articles which strip away the qualifiers are such studies definitive.
Starchild
01-31-2015, 08:42
The way that link is done it seems weird for what is suppose to be a scientific study. And it does have me question their competence and or motive.
It already tells us things we know and presents those things like they are new finding that they made, like UV (well Steripen) does not kill the 'buggies', we knew that, it is posted on the Steripen site, UV just damages the DNA, they are still alive. It does go on to state that they were found able to reproduce, this goes against the steripen's claim and perhaps something that can be verified.
They also state municipal plants use UV in combination with another method, This last one btw is done not for the purpose of getting every last germ, but to leave a residual in the water to prevent down stream contamination. They fail to state this, either they are unaware of this or do not want to state it. Both are red flags that they may not be qualified to perform such a study.
Stating that some muni plants just use UV alone would seem to indicate that it is effective (and they should question why that is, which they do not). However they take it the other way, that because some also use chemical treatment they seem to take it as proof that it is not effective - this is not the logical conclusion, and the reason for chemical treatment normally to leave a residual, which again they do not state.
And as stated above all the qualifiers that they use only suggest that perhaps more study is needed, and that too is stated on the Steripen web site.
It just seems sloppy and that they did not do their homework, and sloppyness is not something that one can afford in such a study.
However with this said, the manufacture of Steripen have stated that once they got it proven to be effective they didn't care to do so again because animal testing was used which they are opposed to. For such a widly used device having more studies of it's effectiveness would be of benefit and this study may push them or others to do so.
For such a widly used device having more studies of it's effectiveness would be of benefit and this study may push them or others to do so.
If the device is widely used, then studies are conducted daily. The studies are good to have, but what I really care about is not having projectile diarrhea on the trail. If I treat all my water with a Steripen and I don't have to visit every latrine on the trail, then there are 3 possibilities:
1. Every water source I pick is clean and pure.
2. The Steripen is effective.
3. My immune sysytem and GI tract are Kryptonian in strength.
I don't care which one is really the case, since I get to hike and drink. For what it is worth (and, I am aware that "data" is not the plural of "anecdote"), I haven't heard any stories of illness despite Steripen use, but that may just mean that I need to get out more.
Offshore
01-31-2015, 12:26
If the device is widely used, then studies are conducted daily..
Not particularly statistically or scientifically valid studies, but more like empirical data collection. A point that seems to be overlooked is that the study cited was done under controlled laboratory conditions - and under ideal conditions still cast doubt on the efficacy of UV disinfection. Contrast that with how a Steripen typically gets used in the field - probably less than ideal conditions. No doubt a lot of people have used SteriPens with good results, but personally I never considered one. Compared to the alternatives, it just has too many potential points of failure. With so many good, proven low-tech alternatives like filters and chlorine dioxide available, why go with a more technologically complex solution that may or may not be as effective as the marketing states?
The "study" does not address the fact UV lamps are not equal.
I think the Municipalities that have UV have fully shielded UV.
mÜV, made in the USA, is certified in the USA.
If I purchased a UV water purification device, it would be mÜV.
Steripen, made in the USA, has a "credential" from an organization in Canada.
I will not own a Steripen because I am never impressed by "testimonials" - my reaction is just the opposite: it looks like a "hustle" to me. The website is practically entirely "testimonials". I read about the owner, but his achievement apparently was not the Steripen.
LuckyMan
01-31-2015, 13:20
I learned the hard way that the Steripen Adventurer Opti is extremely unreliable, and a pair of $17 batteries failed after only four days. Even if it works as advertised, which is a big if, it will treat only 50 liters of water per set of batteries. The cost per liter of water treated is far higher than Aquamira or a filter, and unlike my Steripen, my Aquamira has never simply stopped working in the middle of nowhere. Aquamira also weighs a lot less.
Offshore
01-31-2015, 13:23
The "study" does not address the fact UV lamps are not equal.
UV lamps intended for disinfection are pretty much equal in terms of UV-C wavelength (both the Steripen and mUV are 254 nm). What can be different in the systems is the dose of UV light which is adjusted by either UV intensity or by length of exposure. I doubt very much if there is a lot of appreciable intensity difference in the UV lamps in the mUV or the Steripen - they would become hazardous to eyes at higher intensities. If the treatment times are equal, its a pretty good indication that the lamps are exactly the same.
Its also important to note that these are sold as water "purification" devices - a word that can mean different things to different people. UV systems - whether in your municipal water plant or in your backpack - are intended for disinfection (reduction of pathogens to a level where they are incapable of causing disease), not sterilization (killing or removal of all pathogens). I really don't think there's a lot of difference between SteriPen and mUV - which is why I'll pass on both. I can get better results with a more reliable means of treatment - Aquamira and/or a Sawyer filter. No batteries or electronic parts to fail in the middle of nowhere.
No surprise.
Forget gadgets with batteries for long distance hiking.
+1
I don't want my "safety" gear to rely on batteries.
Starchild
01-31-2015, 19:40
+1
I don't want my "safety" gear to rely on batteries.
This really has very little, if anything to do with the OP, and very little to do with reality. Steripen users in general do not depend on batteries, but just enjoy lighter weight hiking if the device is functioning properly, most could use a alternate method such as a chemical treatment and incur the weight penalty of such treatment if needs be. But your statement does not reflect reality, just a great sound bite.
When has a green thread ever been strictly on topic?
FWIW, I didn't mention batteries, first.
Starchild, Please put me on your IGNORE list. Then, you need not ever be troubled with me again.
Starchild
01-31-2015, 20:00
\
Starchild, Please put me on your IGNORE list. Then, you need not ever be troubled with me again.
Not-My-Problem
Batteries.
http://www.steripen.com/batteries/
Slo-go'en
01-31-2015, 22:14
Even if the uV is effective, it doesn't remove dirt from the water which is primarily what I use a filter for.
MagnumCJ
01-31-2015, 22:15
I personally have no doubts about the effectiveness of uv light and its sanitizing effects. It's been used at the food plant I work at for at least 30 years. However,I an concerned about the effectiveness of the steripen based on the actual exposure water gets from it in the field. I would like to see concrete proof though as I really like the idea
I get "my back up" because SteriPEN is made in the USA and SteriPEN does not have a certificate, here, in the USA. The organization cited at their website is a .org in Canada.
That organization, however, may have credability in Canada.
Nevertheless, it is a USA product. Where is a credential, here?
mÜV is made in the USA and has a credential here.
Even so, UV "effectiveness" is strength of the UV and duration of the UV and exposure to the UV.
Even the UV of the Sun is not effective for this purpose, water purity, without those three criteria.
Tuckahoe
02-01-2015, 08:05
First, I do not understand the issue with supposedly having the Stripen "certified" by a Canadian organization. Canada is afterall a modern 1st world country with the same, very similar, or even more stringent manufacturing standards. US, EU and Canadian standards are all top tier as far as I am concerned and an objection is misplaced.
Second, the only "certification" discussed on the Steripen website is from the Water Quality Association based on US EPA standards --
SteriPEN products have been tested by the Water Quality Association (WQA) against the US EPA Microbiological Water Purifier Standard. SteriPEN has received the WQA’s Gold Seal, certifying that SteriPEN purifies water safely and effectively.
Standards that the WQA tests against -- https://www.wqa.org/Programs-Services/Product-Certification/Product-Certification-Areas
WQA is headquartered in Lisle, Illinois.
Steripen does publish favorable lab results from laboratory and university testing -- http://www.steripen.com/micro-biological-testing/
Can you point out where it has been only certified in Canada?
That's nice:
That "micro-biological-testing" has been added to the website, since the last thread about certification.
edit: I can't see the WQA website link, now, because the Safari browser in my iPod cannot verify the server. I have never seen that before. Maybe their website has a re-direct? This link works: http://www.wqa.org/Programs-Services/Product-Certification/Certification-Trademarks I did Google Search: WQA Lisle, IL turns up a private sector NPO.
Why would I have taken issue?
It is right for purchasers to have an expectation of the USA water quality standard of the approved government entity.
Traveler
02-01-2015, 10:18
It is right for purchasers to have an expectation of the USA water quality standard of the approved government entity.
A good point here, we as a nation are pretty secure in our presumption that potable water in all forms meets standards of an approved government agency. The item here is more in the "caveat emptor" (let the buyer beware) category. There is no government entity that is in charge of what you can buy to treat or carry potable water.
The Water Quality Association is a not for profit international trade association that represents residential, commercial, and industrial water treatment industries. Their membership is comprised of equipment manufacturers, suppliers, dealers, and distributors of water quality improvement products and services. The product certification this organization provides is basically to assure claims made by a manufacturers product are backed by testing data (which may be from the manufacturer). While this may be a fine organization dedicated to the sustainability of making things to treat, store, or convey potable water, this is by no means a government or quasi-government organization.
Trade associations like this are common, usually acting as industry advocates and sustaining industry practices. Though better than nothing, industry trade groups tend to lean in the direction of their dues paying members (manufacturers, etc) and perhaps charging for testing. Consumer Report would be a good example of a group that tests the assertions of manufacturers and takes no money from those they test, nor from anyone associated with the particular industry.
As for a government agency, there aren't any for this type of stuff. You are free to treat or not treat any water you find and capture for your personal use with whatever chemical or device that you wish to use. The only time government has an issue is if you treat water and return it to the environment without a permit, which is rare on an individual level.
Offshore
02-01-2015, 11:13
I get "my back up" because SteriPEN is made in the USA and SteriPEN does not have a certificate, here, in the USA. The organization cited at their website is a .org in Canada.
That organization, however, may have credability in Canada.
Nevertheless, it is a USA product. Where is a credential, here?
mÜV is made in the USA and has a credential here.
Even so, UV "effectiveness" is strength of the UV and duration of the UV and exposure to the UV.
Even the UV of the Sun is not effective for this purpose, water purity, without those three criteria.
I wouldn't get so hung up on where something is made vs. where it is "certified". I suspect that both the SteriPen and mUV are manufactured in China, although there is no information that I could find on either site that says where the devices are made. The UV lamps in the SteriPen and mUV look to be exactly the same and they are probably using the same bulb. The differences are all marketing, and Steripen seems to be way, way ahead of mUV on that front.
As pointed out earlier in the thread, the certifying organization for SteriPen appears to be nothing more than a trade group - they may be using recognized and accepted testing protocols and the information may be accurate - but regardless of where they are based, there is an inherent conflict of interest. To their credit, they do have actual laboratory test data for their products available on their site.
Looking at Meridian Designs site, I see an "efficacy report" for only one of the two models (the AquastarPlus! model, not the mUV), and that report appears to be written by manufacturer back in 2005. Even worse its really nothing more than an expanded user manual covering use and theory, with lots of references to (possibly outdated) EPA documents talking about the efficacy of UV disinfection in general. There are no specifics about the disinfection efficacy of the AquastarPlus! itself - the only actual data pertaining to the AquaStar Plus! is a short table of transmittance data. As for the mUV - nothing but an 8 page user manual.
AT Traveler is right - its buyer beware. Personally, if I had to use one as a last resort, I'd go with Steripen. (But I still prefer the simplicity of filters or chlorine dioxide. Less potential points of failure in the process.)
The article starts our with a misconception: "Although ultraviolet (UV) light successfully kills some microbes without introducing harmful chemicals to drinking water, it may not completely disinfect. Instead of killing all bacteria..."
UV light doesn't kill microbes, it renders them infertile so they don't multiply in your guts and make you sick. Pick whatever water treatment method you like, keep your hands clean, and go have fun.
MuddyWaters
02-02-2015, 22:52
Its interesting that steripen only claims a 4-log reduction. Most water purification is based on 6 log for bacteria, and thats the biggest threat. One in 10,000 x vs one in 1,000,000.
Again, if drinking sewage, it matters. If drinking clear springs, it likely does not.
Traveler
02-03-2015, 08:26
Its interesting that steripen only claims a 4-log reduction. Most water purification is based on 6 log for bacteria, and thats the biggest threat. One in 10,000 x vs one in 1,000,000.
Again, if drinking sewage, it matters. If drinking clear springs, it likely does not.
Then there are the nuances of all the water sources between raw sewage and pristine granite lined spring aquifers, which likely do matter and comprise the vast majority of water sources. Oddly, the only time I got Giardia was at the only spring water source I didn't treat near the crest of the presidential range in NH. It should have been "pure", but it wasn't.
One of the issues of UV treatment of pathogens in water is turbidity. UV does not work in murky water, requiring it to be filtered reasonably well before it will be anything close to effective. I