Apr 30, 2010 at 11:44 am #1258384
@johnaLocale: Great Lakes State
Now there's an appetizing subject line.
I theoretically have an Isle Royale trip sometime in my future and understand I should take these into account when treating water there. I enjoy using my Steripen but it seems that alone won't cut it in this case. What should I use to supplement it? Will just a bandanna filter do it? Small brass screen (fuel/coffee filter)? Just skip the UV and bring a "real" filter and chemicals?
JohnAApr 30, 2010 at 12:10 pm #1604128
I'll happily defer to folks who've hiked there, but it looks to me like filtration would be more dependable than UV or chemical treatment. The eggs are fairly large, larger than giardia cysts anyway, so any filter adequate for those would certainly remove tapeworm eggs too. You wouldn't need a bacterial-level filter.
However, I can't find a reference that says a "prefilter"-type filter would be adequate. The results from ingesting the critters is ghoulish enough that I'd trade some inconvenience for the peace of mind (but maybe that's just me :-)
I guess you could buy some and experiment.
RickApr 30, 2010 at 12:21 pm #1604132
@arichardson6Locale: North East
From that site: Collected at Владивосток Vladivostok Soviet prison camp in one liter slurry of liquid human excrement.
Sounds like a dirty job gathering those eggs.Apr 30, 2010 at 12:36 pm #1604141
Chemicals — takes too long to kill big baddies.
Filters — heavy/intricate to trap the really tiny baddies
I like my combo method:
1. use chlorine to kill the truly tiny (cheap, light and requires just a reasonable 30 minutes treatment time regardless of water temperature)
2. then suck water through a simple UL filter to trap the biggies that take chemicals far too long to treat — and also to clarify water and remove bad taste (chlorine, etc.).
I pair chlorine with a 2oz. Frontier Pro.Apr 30, 2010 at 1:23 pm #1604172
@johnaLocale: Great Lakes State
Hmmm…I'm seeing 25.0 microns for the eggs. Is that still too small for some light, simple screen to pair with the UV? Not that I'm anxious to gamble with my insides, just wondering what the options are.
JohnAApr 30, 2010 at 1:51 pm #1604183
UV is supposed to kill everything microscopic. And when in doubt, it never hurts to zap the water a second time. My thing against UV is not its efficacy (I trust it) — but just the eeewww factor regarding muddy brown rivers or green algae ponds — plus the sometimes funky taste.May 1, 2010 at 6:30 am #1604535
@dpnollLocale: Maroon Bells
For Isle Royale you are better off sucking it up and actually filtering. We use a gravity filter and have had no problems in three trips. You really don't want to take a chance with tapeworms.May 1, 2010 at 8:50 am #1604568
Roleigh Martin favors this nice 3 oz combination of prefiltering, filtering and chemicals.
I'm a bit less cautious than he is and would be inclined to use just the prefilter and chems but that's a choice you'll have to make for yourself.May 1, 2010 at 10:57 am #1604618
Right, I wouldn't rely on UV without definitive testing results confirming it inactivates these specific eggs. Hospitals, for example, can't rely on UV for surface disinfection for drug-resistant bacteria because the cyst forms of some of them are UV-resistant.
RickMay 1, 2010 at 10:59 am #1604620
Do you have a link to the above? Thanks.May 1, 2010 at 4:13 pm #1604707
I heard an epidemiologist interviewed last week about avoidable hospital infections and the spread of yet more drug-resistant bacteria strains. He discussed effective surface sterilization (or the lack thereof) and they evidently rely heavily on chemical sterilization (bleach, etc.). He discussed UV only to the extent that it's not particularly effective in this role.
It got me poking around; so far I've found this at CDC.
"Bacteria and viruses are more easily killed by UV light than are bacterial spores…."
RickMay 1, 2010 at 4:51 pm #1604717
Thanks, Rick. Per your CDC link:
"Ultraviolet Radiation (UV)
The wavelength of UV radiation ranges from 328 nm to 210 nm (3280 A to 2100 A). Its maximum bactericidal effect occurs at 240–280 nm. Mercury vapor lamps emit more than 90% of their radiation at 253.7 nm, which is near the maximum microbicidal activity. Inactivation of microorganisms results from destruction of nucleic acid through induction of thymine dimers. UV radiation has been employed in the disinfection of drinking water, air, titanium implants, and contact lenses. Bacteria and viruses are more easily killed by UV light than are bacterial spores.
UV radiation has several potential applications, but unfortunately its germicidal effectiveness and use is influenced by organic matter; wavelength; type of suspension; temperature; type of microorganism; and UV intensity, which is affected by distance and dirty tubes 779. The application of UV radiation in the health-care environment (i.e., operating rooms, isolation rooms, and biologic safety cabinets) is limited to destruction of airborne organisms or inactivation of microorganisms on surfaces. The effect of UV radiation on postoperative wound infections was investigated in a double-blind, randomized study in five university medical centers. After following 14,854 patients over a 2-year period, the investigators reported the overall wound infection rate was unaffected by UV radiation, although postoperative infection in the "refined clean" surgical procedures decreased significantly (3.8%–2.9%). No data support the use of UV lamps in isolation rooms, and this practice has caused at least one epidemic of UV-induced skin erythema and keratoconjunctivitis in hospital patients and visitors."
I think this has more to do with the alleged ineffectiveness of UV lamps used in rooms and cabinets (I have a Sharper Image room air purifier that includes a UV tube). Not an expert, but inserting a UV tube in a much smaller 16 or 32oz water container is probably a lot more intense — and effective???May 1, 2010 at 4:55 pm #1604718
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
With the relatively huge size of tapeworm eggs etc, it may be that a paper coffee filter (or some other coarse filter paper) followed by the Steripen might be an effective and fast combination.
CheersMay 1, 2010 at 5:28 pm #1604731
Are tapeworm eggs visible to the naked eye? Would people know to whip out their coffee filters?May 4, 2010 at 11:02 am #1605873
John, skip the fuss and the combo treatments.
I use the Sawyer SP-121 inline filter on Isle Royale. Works great. Weighs less than 2 ounces. Filters smaller (ie more stuff) than other filters. Works great, easy to use. You can just stick it inline in your hydration bladder and drink away. Or hang the bladder in a tree and gravity feed.
Very light, very compact, very easy. If you'll be out over a week, you might want a way to backflush. Can still suck water thru easily, but filtering for 2 the flow noticeably dropped after ~1wk. Backflush, good to go. I rigged a platy bottle with a short piece of hose and fitting I can plug into my hydration hose to use for field back-flushing.
(Have considered adding a tiny, very coarse inline filter, but haven't come up w/something suitable yet. Considering a piece of coffee filter wire mesh in the cap of my bladder.)May 25, 2010 at 7:39 am #1613533
I would add a little extra piece of wire mesh in there.
Make sure you are using one of the finest of meshes, so nothing, even something very small, has a chance of getting through.
Use this site to measure the wire mesh that you plan on using, and try to attain some samples so you know exactly what you are going to get when ordered.
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