Chemicals, Filters, or Neither!

[Stephan Guyenet]

This is all very informative. However, there is one crucial piece of information that hasn’t been discussed yet in this thread: the likelihood of contracting the pathogens we’ve mentioned.

It’s not much help getting worked up about all the diseases we could catch if many of them are rare or don’t occur in the places we frequent.

For example, you hear a lot of talk about Giardia because this is a common organism in most areas of the US. I’m sure some of these other pathogens are quite nasty but why don’t we hear much about them? I’m going to make the ignorant assumption that they are rare or difficult for most people to contract. Otherwise, why wouldn’t everyone using iodine, other chemicals or UV to purify their water be riddled with tapeworms?

[paul johnson]

read again prev. post on hydatid tapes. note specifically the bold “the good news is” as far as hydatid tapes are concerned.

likelihood varies depending upon locale and other factors (see one paragraph in post dated 09/08/2005 at 16:06:55 MDT).

as far as difficult to contract. depends upon what you mean. they’re difficult to contract b/c we don’t usually encounter them in some parts of the country. on the other hand some of them e.g., crypto & tapes may cause infection if even just ONE spore/egg is ingested. this is based upon tests performed on volunteer human “guinea pigs”.

no need to get scared or all worked up about them (“Lions and tigers and bears, oh my!” ; “The sky is falling”). does one get scared just because they’re hiking in grizzly country? wouldn’t that take all of the enjoyment out of hiking? just, based upon the area one is hiking in, take the appropriate precautions. some areas still may not require any special precautions. out here in the east, 35-45 yrs ago, i used to drink freely from all sorts of water sources without any filtering or treating. wouldn’t do it now however. i occasionally see people post things that are appropriate for the high Rockies or somewhere else out west. not sure that those precise conditions exist out here in the east with the lowland, higher popluation density, & dairy and poultry farms.

one thing we haven’t gotten into here (maybe i missed it?) is chemical pollution of water (often with carcinogenic chemicals). again, more of an issue here in the east with the population density & factories being so much nearer to water sources that end up going through state parks and forests. no much we can do about chem. pollution anyways – at least with the standard filters and chemicals we use (activated charcoal is not a panacea for all chem. pollution; sometimes more sophisticated techniques are required to remove some chems).

[Scott Ashdown]

Well, thanks everyone for contributing some really horrible stuff. After reading the above you just can’t look at a glass of water in the same way. Cysts growing in your brain for twenty years, yikes!!!!!! From now on, I’ll pack both my Katadyn hiker filter and my steripen to be sure instead of just one or the other as I have done in the past.

Scott.

[paul johnson]

Stephan makes a good point. who knows (i sure don’t), maybe one has a greater chance of being struck by lightning while camping than of contracting some nasty bug? probably, mostly depends upon where one is and what water source one drinks from.

[Al Clemens]

Paul,

In your post above you mention that boiling kills some, but not all pathogens. Could you elaborate on this?

I don’t have a background in biology such as yourself, but have always heard/read otherwise. The classic mountaineers reference bible, Freedom Of The Hills (6th edition 1997)claims boiling to be the most effective water treatment method, killing all pathogens. It goes on to say (and here I’m a bit suspicious) that extended boiling is not necessary even at altitudes as high as Everest. Although not biology reference material, this book which has beeen ongoing since it’s first edition in 1960, is written and updated by a panel of experts in each area. So, I took this as fact.

Boiling certainly isn’t the water purification method of choice, especially by weight weenies. It’s a common practice of winter campers that have no choice but to melt snow/ice for water though.

[paul johnson]

Al,

don’t take the following as “all inclusive”. i could be forgetting something important. as i’ve stated elsewhere it’s been 30yrs since i’ve worked in this field. i’m making this post long in an attempt to answer any additional questions that might come up. hope i don’t confuse the issue further or put anyone to sleep.

i should further note that 4yrs ago i had an accident that left me with permanent physical and cognitive deficiencies (memory being one of them) cp. to my pre-accident state. without going into detail, my memory used to be quite good. now, my memory is not, euphemistically, what it used to be 4yrs ago. if i’m not certain of something, or think that i may not be recalling something correctly, i will say so. however, that said, i’m not always certain that i may not be recalling something accurately, so it’s best to check a more authoritative source.

1. even boiling, at sea level, for a reasonable period of time won’t kill all pathogens/parasites. this is why sterilization in laboratories and hospitals is done, typically (30yrs ago) using one of two diff. methods depending upon the items being sterilized. 15min at 15psi above atmospheric pressure (water boils at 250deg F at this pressure) will kill anything – this is commonly done in a hot steam autoclave. some type of “ethylene” gas (as i recall – can’t really remember precisely what gas) is used for gauze, towels, etc (basically, anything that should not be exposed to high temps or moisture). on the other hand, since milk can’t survive high temps (casein, lactose, and other chemicals in the milk would be affected), milk is commonly pasteurized (some little buggers survive in very low numbers) using one of two methods – HTST (hi temp short time) which is (i hope i recall this accurately) 180 deg F for about 15 or 20 seconds, or LTLT (lo temp long time) – i think this is about 160 deg F for a couple of minutes (i’m really forgetting this one, so you should check it out). i only mention these facts so that a fuller picture is given of what it takes to kill “germs” using temperature. pastuerization is used on milk so that it doesn’t spoil as quickly (and to kill some enteric, or found in the gut, pathogens which are more sensitive to heat) that is supposedly already safe and free from pathogens due to antibiotics and clean, non-contaminated milking methods. so, pasteurization techniques should not be interpreted as being appropriate for sterilization and killing of all pathogens.

2. i said pathogens – most (not all) which are NOT normally encountered in water. that’s the good news. these pathogens normally inhabit soil (or infected cattle & humans – this will become clearer in a moment).

3. those that you might encounter in water, viz. some eggs of worms and some protozoans (again, there might be others, even in No. Amer. that i’m forgetting) can be killed by boiling, but you need 10 minutes (to be safe) of a rolling boil at sea level boiling temps. obviously, higher elevations will require more time at a rolling boil (BUT the less likely you are to encounter any pathogens/parasites – generally speaking). so, in a survival/emergency situation, you could do so – it’s much too fuel inefficient for normal purification means. it’s NOT enough to simply bring the water to a boil. a rolling boil should be maintained for at least 10minutes. how many really do this however? 10min. is a long time!!

4. now, what are the little buggers that won’t be killed by boiling – for any reasonable period of time, if at all? these are primarily soil bacteria, though it’s possible (though very unlikely) that they can be encountered in water (diseased cow dies on the edge of a barely moving body of water; it’s legs are sticking up out of the water and so is part of it’s bloated body – but it goes unnoticed as do the vultures circling overhead and the ravens picking at the carcass?!!! i hope you get the point i’m making here). mainly two related genuses of spore forming bacteria. three anaerobic species and one aerobic cousin. these are some of the largest non-spirochete (non spiral shaped bacteria like those causing syphillus & lyme’s disease) bacteria. as i recall, they are over 1.5microns in length, sometimes 2 or 2.5 microns in length. they are over 0.5 microns in diameter. they are all bacilli, or rod/cylindrical shaped bacteria with rounded ends. all stain “gram-positive” and so have ~80% mucopeptides in their cell wall and therefore are generally quite susceptible to penicillin or penicillin -type/-derived antibiotics (inhibibit cell-wall synthesis in “gram-positive” bacteria due to the high mucopeptide content), as well as some newer types of anti-biotics i’m not very familiar with.

Clostridium botulinum (causes botulism)

Clostridium tetani causes tetanus, “lock jaw” – found in soil, NOT rust – however if you step on a nail, it is usually on the ground in contact with soil [unless you’re a “roofer”] – puncture wounds are the concern here, NOT lacerations. punctures often heal at the top first, leaving a void beneath – C. tetani is anaerobic & loves this enviroment since oxygen is rapidly depleted from it – any type of wound that heals from the bottom to top is generally NOT a candidate for C. tetani colonization.

Clostridium perfringens (causes gas gangrene aka gangrene – very nasty visual & olfactory effects – seen & smelled it, not pleasant – even less so for the person infected)

Bacillus anthracis causes anthrax, nasty disease (two main forms of the disease) – but terrorism has taught us all about this bug. even this guy, 30yrs ago, was cultured in college micro. classes by undergraduates – it just wasn’t inhaled, injected under the skin, eaten, aerosolized, or turned into so-called “weapons” grade anthrax. in fact, to prevent theft, used to keep my lunch in the biohazard refrigerator having many cultures of pathogenic bacteria – all safely in “stoppered” test tubes (rules weren’t followed as strictly then as they are now). maybe this accounts for how i turned out??? sure explains alot!!!

these bacteria form endospores when they encounter an inhospitable environment. this protects them until they can find a nice, cozy environment. as far as i know, it’s extremely unlikely that anyone will contract these from drinking water. the worm eggs are more likely (and still very rare apparently). i’ve only mentioned the “boiling” issue prev. for two reasons: 1) to correct a common misconception that “boiling” is to “bugs” as kryptonite is to Superman – not exactly true., and 2) if one understands more fully the limitations and consequences, then one can make a more informed choice/decision.

am i concerned at all about any of these four bacteria in water in the wilds? no. but i’m not going to throw a bunch of nice dark soil (diff from sand) into the water and then bring it to a boil and drink it, nor am i going to drink any water that has a bloated cow in it. beyond that, my prev. comments were more for being precise (dotting every “i” and crossing every “t” – it’s an anal-retentive, Type A, OCD fault of mine – drives my wife crazy – she’s a saint, so she’s put up with it for 26yrs, and it’s only gettin’ worse as senility sets in).

all of the above bugs should be easily filtered out using a 0.2micron absolute pore size filter, or in some cases, depending upon filter design, a sub-micron nominal pore size filter employing a labyrinth design (this is essentially how natural soil filtration works).

for my part: i generally use just AqM for purifying water. if i were really concerned about a water source, then filter (using a 0.2micron ceramic filter) & either chem. treat using AqM or UV-C.

hope i didn’t upset anyone previously. if this fails to ans. you questions, please post back & i’ll try to be briefer and clearer in my answer to more specific questions. being responsible just for myself and posting advice/info for others are two diff. things in my mind, requiring diff. levels of “preciseness” and caution – hence this long post.

i’m about at the point of ending any kind of technical post on this and other subjects which i’m very interested in. i need to remember not everyone has the same level of interest in the same subjects i’m interested in (be warned: if you think this post is long, don’t ever get me started on Auto Sports, performance driving skills, performance modifications to street cars, or auto repair – not that these have any place on a BackPacking website.). furthermore, i’m thinking that i cause more problems and raise more questions than i answer.

i really wish a medical doctor, or an experienced microbiologist with more recent, more thorough knowledge would chime in here and help out. is there a doctor in the house?

’nuff said.

[Al Clemens]

Paul,

Thanks for the reply! I certainly wasn’t upset. Just confused with two contradictory sources of information.

From what you mention, there are pathogens (in soil and animals) that are potentially resistant to a boil and there certainly is the possibility of incidental contamination of water from them. I was aware of lower heat treatment pasteurization methods for milk (and beer!)where some organisms survived and others didn’t – so didn’t discount the possibilities of other more robust organisms being able to tolerate higher temperatures.

Freedom Of The Hills target audience is primarily mountaineers. Their recommendation of boiling as the safest method in the 1997 edition, was in comparison to Iodine and filtration as treatment methods. I believe Aqua Mira was pretty new at the time as was the newer smaller pore size filters like First Need that are claim to pass EPA protocol for virus removal -so these aren’t compared/discussed. It’s now in it’s 7th editon so this may have been updated. I’ve read that Iodine and Aquamira take hours to wipe out crypto (especially in cold and/or dirty water) and around a half hour to kill giardia, so there is room for user error here. Ceramic and resin matrix filter cartridges can suffer internal cracks when frozen (I’ve had it happen) and pass through pathogens afterward, so room for error here too. In comparison, boiling could be considered less susceptable to user error.

If the boiling point on Everest is ~155°F, that’s still below that of the lower heat, longer dwell pasteurization method you mentioned. Around the upper reaches of Everest and other 8000+m peaks, it’s frozen year round and inhospatible to most animal hosts. The diminishing boiling point as altitude increases works somewhat in proportion to the diminished animal/pathogenic orgainsm life in higher elevations. So, I suppose this could be their justification for saying that extended boiling time isn’t necessary on Everest. Still, seems a litle shaky though.

I don’t want to offend anyone either by constantly single source referencing Freedom Of The Hills either. But, it is considered the “gold standard” as reference for mountaineering and outdoor practices.

[David Bonn]

Actually, there really hasn’t been very much honest research in this area.

There have been a few surveys of backcountry water quality — they have uniformly shown that there is neglible risk of contracting waterborne diseases in the areas studied.

What there hasn’t been (as far as I know) is any wide-ranging study that shoes an elevated risk for such water-borne diseases and an activity like backpacking. In theory, if there is an elevated risk, it should show up pretty clearly. Based on the various water quality surveys (which show that any potentially infective water is rare), my other guess is that you could also probably isolate quite a few outbreaks by the location of infection.

The real world is unfortunately more complicated. Most people use some form of water treatment. None of them are one hundred percent effective, especially out in the field, but it would still dilute any effects. Also, the typical symptoms of even the most heinous waterborne diseases are generally mild and a lot of people skip visiting a doctor. It is also difficult in the absence of a stool culture (fun gather and playing with that) exactly what disease we are talking about, and figuring out where it the victim acquired it is harder still.

In the absence of hard data, I’ll stick to my own suspicions: backcountry water, is, on the average, pretty darned safe to drink. Not washing your hands after you poop, handling shared food with unclean hands, drinking from a shared water bottle, or a post-hike dinner and salad bar are all probably far more risky than drinking from that creek.

[paul johnson]

Al,

didn’t think that you were upset. very sorry to have confused you.

great info. thanks for replying and sharing it. i really appreciate it. always like to learn something new.

not every bug is resistant to heat. 155 should be good enough as long as the time is long enough. sorry, i don’t have any numbers in my head for how long is long enough for 155. figure at least 10+ minutes though as this is a figure given for some worm eggs and protozoan spores (but at sea level altitudes). i would guess that some types of bacterial pathogens and viruses will be dispensed with before the 10min even at 155. but, again, i don’t have any numbers floating around in my head. mountaineering was never the focus of my “micro” education. obviously, as we both stated in prev. posts as you go up in altitude there is less chance of encountering anything bad.

as far as freezing. i had never considered this aspect of a filter. thanks again for sharing it. this makes me wonder if there isn’t still something that can be done with filtration. ~30yrs or so ago a company called Millipore introduced a very thin single layer flexible membrane sub-micron filter used in coliform testing of potable water sources such as wells and reservoirs (as well as lakes, streams, oceans – pretty much any water source). used them one summer working in a small, private soil and water environmental testing lab. what do you think, could such technology be used to filter water in the backcountry? the flexible filter may survive freezing (don’t know for sure, but would have to look into it) & instead of a 110VAC powered pump, like in a laboratory, either a batt operated pump or a foot pump could be used force the untreated water through the filter membrane. so, what do you think? is this a good idea waiting to go into production, or is it another ill conceived concept brought to you by your friends at “Bad Ideas R Us” – pj, proprietor.

based upon what you’ve pointed out, maybe boiling water is the best treatment option at these temps, assuming you have the fuel to burn (not much wood around there, right), otherwise you’ll just have to warm the water up a bit & then chemically or UV-C treat it (chem & UV-C resistant eggs are very unlikely to be found up high – even less so, than down at lower altitiudes).

[paul johnson]

David,

I believe you make some excellent, valid points. You sure seem to have a good grasp of certain aspects of Epidemiology. I would only suggest that you keep this in mind, most of the “studies” i’ve read recently, based upon other Threads & Posts here, talk about western water sources. the situation here in the lowlands, highly populated, NorthEast with farms all around may be quite different. i think that you are alluding to this fact in your words “areas studied”, so my comments here may be unecessary for you. you probably already thought of this. i only mention this in case any other reader was not aware that this may be a possiblilty.

thanks for posting and sharing your knowledge. i appreciate it.

[Al Clemens]

Paul,

Filtering is still a winter water treatment possibility. As long as you have a filter with an element that isn’t damaged by freezing and the moving parts still work. Hard to get all the residual water out of the element and mechanicals, or constantly keep warm so they don’t seize, or frozen element impedes flow. To my knowledge, the only two freeze resistant portable units are the Katadyn Hiker with pleated fiber element and MSR Sweetwater with flexible rubber like element. From what I read in mfg literature, all the ceramic filters the likes of MSR Waterworks/Miniworks and Katadyn Pocket filter are freeze and shock sensitive. I would also suspect this of the Seychelle plastic element filter sold here as well. The filter (purifier)that I had freeze was a General Ecology First Need. These have their own unique resin-matrix element. They have a food coloring dye test solution to run through if you suspect the element may have been damaged by shock or freezing. Cartridge won’t pass diluted dye solution if working properly. I used it at altitude in spring and fall where it was below freezing at night – trying to protect by keeping in my sleeping bag at night etc. Probably exposed to freezing 4 or 5 days before it failed the dye test.

Speaking of this, I’ve heard it said in other backpacking forums that the virus (virii pl?) have a very high likelyhood of being attached to a larger host, like bacteria. That in this instance, they would potentially be trapped by a filter large enough to stop bacteria but not virus alone. Any insight?

[paul johnson]

Al,

thanks again. i’m always learning something from your posts – valuable practical info instead of just technical info.

viruses attached to bacteria…hmm…

had never heard of this before. i’m just a small bit skeptical. actually, now that i think about it just a bit, maybe i’m not. not sure why this would be. now, i do know that there are viruses that attack bacterial cells (“cells” meaning here is multiple individual bacteria. don’t take this to mean bacteria have more than one cell. they are all single celled organisms) in a manner similar to how they attack the cells of a larger multi-cellular organism like humans for instance. these viruses are called bacteriophages. in this case though the virus is a pathogen for the bacteria, not a human. i don’t believe that you were referring to bacteriophages, however. just like bacteria, viruses can be part of a film or attached to particulate matter (maybe a bacterial cell???). however, viruses are considered to be NON-FILTRABLE (they are nano-meter sized instead of micron sized liked bacteria). so even if what you have heard is true, there are still enough virus particles floating around in the water to pass through any filter. with the size difference between bacteria and viruses i guess that multiple virus particles (not bacteriophages) could hitch a ride on the outside of a bacterial cell. just to give you some idea, the T5 bacteriophage that infects the common E. coli bacteria cause the bacterial DNA of the infected E. coli bacterium to replicate ~200 viral cells before the E. coli cell cannot hold any more & it bursts/ruptures (in this case 200 is called the “burst size” – this, by the way, is part of the infection process in humans too).

so, bottom line. 1) guess they could hitch a ride, 2) enough viruses will be “free floating” that they will NOT be filtered out.

oh…also, to my knowledge heat inactivates virus particles very easily (some vaccines are made this way). probably a 140 deg F (an educated guess on my part based upon the temp that easily affects other proteins) is enough to cause the viral protein sheath which surrounds the viral RNA or DNA (only one in a virus, depending on type of virus – never both) to “denature” or unravel (essentially “cooking” the protein), effectively preventing it from attaching to what is know as a “virus receptor site” on the intended host cell (bacterial or human) it wants to infect.

ok. i think ’nuff said on this…unless there is another question or you disagree based upon what you’ve read. then, feel free to post back and either ask the question(s) or correct me.

[Al Clemens]

Paul,

Thanks for the reply. I found one of the posts on backing.net related to the virus issue and did’t find the source as credible,qualified as you.

On a side note, I stopped by REI and looked at the newer 7th edition of Freedom Of The Hills, published 2003. In their section on water treatment they now mention Aqua Mira for chemical treatment, saying it kills virus and bacteria, and evidence suggests it’s effective against giardia and cryptosporidia. I think they’re a little slow on the uptake. Katadyn chlorine dioxide tabs have been EPA approved for such. Likely only a matter of time before AM is too. And they have changed their boiling treatment protocol statement to “maintain a rolling boil for 1 minute regardless of altitude”. By the 8th edition they’ll probably reflect your 10 min suggestion!

Thanks for all the help,
Al

[paul johnson]

Al,

the 10 minutes is to err on the side of caution since at altitude the B.P. of water is lower. again, i have NO research on this (i.e., the 10 minutes comment i made, NOT the lower BP). i just play the “it’s better to be safe than sorry” game sometimes for myself & especially if i give advice to others.

the types of things that need 10+ minutes at 212 degrees aren’t expected to be encountered at altitude, i.e.it is even more unlikely to encounter these pathogens at altitude than in lower areas – and, depending upon locale, it can be quite rare to encounter them in lower areas – some areas do have endemic conditions.

it’s very likely that 1min of a rolling boil will kill enterics which were transfered to the water by some infected person most likely – Salmonella, Shigella (causes bacillary disentary), a couple of more virulent sero-types of E. coli, Hepatitis A virus – all of these are of fecal origin. I can’t remember the actual boiling time required. I know that i knew it once. guess my “old-timers” is acting up.

thanks again for all of the good, practical info you and others have shared in this Thread. i truly appreciate it.

[doug rawlings]

there is no safe drinking water in the world that i know of…no matter how good it looks, or tastes, there’s always a risk of giardia, agro runoff, atmospheric pollutants, and so on…it’s just not worth it….

of note is the exstream filter bottle, which is like a little water treatment plant…it has the usual filtration, but adds an iodine-based filter that will kill any virus that may be present….also, sweetwater makes a nice mechanical filter thats light and compact….if nothing else, carry some chlorine bleach and iodine, or treatment tabs….never drink wild water without prepping it first…you may regret it….

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