Filtering Water: Any scientific evidence that its safe not to?

[SGT Rock]

I would love to take the water samples and mail them to a lab every time I got to town. Sounds like a fun project

[Amigi'sLastStand]

Just remember, we are talking the AT and general mountain topography from what I have read so far.
I carry a filter, but will drink straight from a stream if the conditions are right, for example coming out of the DWG into the park with the Tammany trail overlook ( what the hell is the name of the park?.?. ) As long as I get higher up than the ppl swimming in the stream, I'll drink it all day long, no problem.
However, there are many other hiking places in this country that you would be crazy not to filter. For example, anywhere here in Florida. Or mountains out west if gold or silver has ever been found in the area ( gold and silver are usually found with VERY high concentrations of lead and somtimes mercury ). Giardia and Crypto are not the only reasons to filter.... But then again, ppl use AM for 5-6 months on a thru and dont mind drinking the residual chemical sodium chlorite which is toxic, so what the hell, drink away ppl.

[Alligator]

Neither have I Alligator. The only evidence I see is the evidence from that one article you will probably not get giardias. If you are trying to prove that a filter or chemical is protecting you, shouldn't you also prove that it is there in the first place? Sort of like saying we invaded Iraq to get WMDs. GW could say there are none here because we invaded using the same logic as saying using a filter keeps you healthy drinking springwater.

The evidence is weak, thus the varying positions. Some people have gotten giardia along the AT. Maybe not as many as is reported due to other causes. (All I need is for you to agree on some ) Filters and chemicals are tested as to effectiveness. Therefore, there is evidence of the presence of giardia, but not amount, and methods (tested) to remove giardia. What is lacking is where and how much. Filters and chemicals are protecting you, if there is giardia and/or other microorganisms present. None to some.

[SGT Rock]

Ohh I agree some people get giardia. But I have read people from the trail (in journals and books) say the had giardia without any proof other than a feeling or belief - and if that is the proof people are using to justify needing a filter it is less than scientific as well, it is anecdotal. And the evidence (the symptoms and recovery) actually point to something other than giardia, but that can be ignored in the quest to find an easy fix to stay safe.

But for the people that do get giardia, what is the background behind how they actually got it? And what other information that could also contribute like a lack of prior exposure to develop resistance? Is it always water? Could it be other forms of contact?

Guys like LWolf are anecdotal evidence as to how safe it is to do without any treatment or filter. But based on what that article says about how hard it is to contract it, and if contracted how low the effects are, and if effected how easy it is to get over it without treatment, some of the prevention systems seem sort of like overkill to me.

Add to that the anecdotal evidence from guys like LWolf with what this article says about building immunity and you may not really need that filter or treatment if you know how to chose water and have a healthy, exposed system. But like I said, people need faith they are protected to feel good about it. If i takes $200 and 1.5 pounds to have that faith I am not going to do much to change that by posting on this web site.

That said, I still treat because it is the lightest way to go and I can do it safely and without taste and it doesn't cost much. It is my faith I reckon - but I don't have a lot of it. I am agnostic when it comes to water danger and treatment effectiveness. I would love to see a study of the real danger and how to avoid it rather than just spending money, lugging weight, and having faith. I doubt it will ever get done.

As for me, hand cleaner and Lyme vaccine. Based on my reads of journals, that is where to protect yourself.

[Two Speed]

. . . However, there are many other hiking places in this country that you would be crazy not to filter. . . Or mountains out west if gold or silver has ever been found in the area ( gold and silver are usually found with VERY high concentrations of lead and somtimes mercury ).

Unfortunately I don't think filtering would help with this type of contamination. First, cyanide leaching was (and still occasionally is) used to concentrate gold out of gold ore, so you get to add cyanide compounds to the mix, among others. Next, the only portable filter element that I'm aware of that could possibly address these types of contaminants is activated charcoal, and that's based on adsorption. Once the charcoal is loaded the contaminant will "break through" and you'll be drinking a very mean contaminant; filter life is going to be extremely limited, if it's effective at all. Last, mine drainage, including the run off from many coal mines, can be very acidic; pH could be a problem even if the contaminants are removed.

Unfortunately, there's only two ways I know of to make this type of water potable:

1. Chemical treatment, by which I mean chemical reaction to cause the contaminant to settle, or possibly acid cracking and then pH adjustment (Iodine or chlorine treatment would just add to the brew, making the problem worse.)
2. A heck of a lot of dilution from uncontaminated sources

If there's someone with a better grip on the technical details I'd appreciate a little schooling, but I believe the above to largely correct.

FWIW, I'm treating less and less of the water I pick up if I'm at high enough elevation, no evidence of camping up gradient, the water looks good, etc. I tend to agree with Weary that much of the concern around this issue is probably based on hype generated by commercial interests that would like all hikers/hunters/outdoorsman to buy one of their products.

[Alligator]

Rock, when you say article in post #45, you are talking about this book-- Mueser, Roland. Long-Distance Hiking?

[TOW]

On a clear running stream I usually never filter my water, but most of the time I do add a chlorine treatment. On occasion I just drink it. I've never had a problem on the trail "yet." Better safe than sorry though...........

[Spock]

SGT,
I think your skepticism about the amount of Giardia on the AT is justified.

I got Giardia, certified, while on a Rio Grande float trip in the 1970's. It took a Mexico-trained doc to figure it out. I'm here to tell you, real Giardia will keep you in close proximity to porcelain for longer than you can imagine. And more violently that you want to know.

What most folks get on the trail is good, old-fashioned tourista. It's gone in 2-3 days and responds quickly to Lomotil or any similar drug. They get it soon after leaving town, probably from a town source. Giardia takes 10-14 days to incubate.

Of course, anyone who doesn't treat beaver pond water is just asking for it.

[highway]

That means that if someone ingests the cyst today from whatever source, whether from contaminated food, water or even after shaking the uncleaned hand from another thruhiker, the same hand which you subsequently use to stuff a wod of your gorp into your mouth, then you may not develop symptoms from the contamination for as long as two whole weeks. In that case, not only will the hiker not know how he/she became contaminated, hell, he/she want even know for sure in which state it occurred! So, the likely culprit is thought to be from water, whether ttrue or not. I still lean towards that unclean handshake

[fiddlehead]

I remember there was a good article on this in Backpacker mag about 4 years ago. It basically said that most AT thru-hikers who get giardia, get it from sharing gorp rather than the water. It's rare to get it from the water unless you are dumb enough to drink from big streams, rivers, ponds etc.
The ground is the best filter out there. when i see water coming out of the ground (unless it is just below the outhouse) i consider it good. The nicest looking stream could easily have Mom washing out baby's diapers a mile upstream. (i've seen that happen more than once)

[weary]

Exactly. I know too many people who have come down with this after not treating water they consumed along the AT. Who wants to have parasites living in their body? Everytime you eat something, you feed the little buggars and get more and more sick. No thanks! I will filter.

Conversely. I know too many people who have come down with this after treating water they consumed along the AT. I therefore choose not to treat my water with chemicals designed to kill living creatures, or carry the weight of a filter.

Weary

[orangebug]

There once was a man standing naked in the middle of Times Square, banging away on a drum. Of course, it took about 2 weeks before anyone really noticed him and asked him what he was up to.

"I'm keeping all of the tigers away from Time Square."

The psychiatrist recognized a delusion and commented "There aren't any tigers around Times Square" hoping to let the man understand the error of his ways.

"Yeh," the man responded. "I'm doing a great job! Thanks for the support!"

I understand he is still standing the pounding on his drum.

*******

This is a little anecdote that illuminates problems with testimonial statements from individuals. I am an non-treater of water. I am confident I will have an equal risk of GI events as other hikers, based mainly on observations of hygiene as a major risk factor in fecal/oral contamination and pathogen vectoring. The fact that I haven't gotten ill from my behavior means nothing about general risk to hikers of untreated water, or from treated water for that matter.

The will never be a study to attempt to measure pathogens in backcountry water sources. Sample size will be small, and ability to detect pathogens will vary by ambient temperature, time to get sample to lab and other impossible to control variables. Plus, there would be a tremendous financial burden to complete this test and a catastrophic financial risk should water treatment be determined to be useless.

At most, anecdotal testimonials will be found, certainly no "scientific" study regarding safety of untreated water. The study I'd love to see is to culture fingernails of hikers obtained at major road crossings every 50-60 miles. I'd expect to see nasties to get more concentrated and to hit a steady state around Virginia. A survey asking about illness would be interesting, but unreliable due to errors associated with self reporting of symptoms.

[Smile]

Cute story orangebug! I had not heard that one before

[weary]

The evidence is weak, thus the varying positions. Some people have gotten giardia along the AT. Maybe not as many as is reported due to other causes. ....

Of course. The question is how they got giardiasis. The evidence as near as I can tell is that most got it from dipping their hands in to a bag of gorp offered by someone who has not practiced good sanitation, or sharing half eatened food, or being licked in the face by a giardia carrying, but friendly dog.

Weary

[bfitz]

A full week after I came off Katahdin I started to get sick, three weeks later I went to the doc and mentioned giardia. He said I was crazy, but I insisted he check my poop. He humored me and told me two days later I didn't have giardia. A couple weeks later I went to another doc and sure enough it was giardia. Got some flagyl and a week later back to normal. Must have picked it up in maine. Never filtered but treated with polar pure if I thought it might be a questionable source. I'm pretty sure it was water, but you never know.

[weary]

A full week after I came off Katahdin I started to get sick, three weeks later I went to the doc and mentioned giardia. He said I was crazy, but I insisted he check my poop. He humored me and told me two days later I didn't have giardia. A couple weeks later I went to another doc and sure enough it was giardia. Got some flagyl and a week later back to normal. Must have picked it up in maine. Never filtered but treated with polar pure if I thought it might be a questionable source. I'm pretty sure it was water, but you never know.

Among the many problems with finding scientific evidence is that the tests are noteoriously inaccurate. I was treated with flagyl once. It did nothing at all for my symptoms. Either it went away by itself or the fiber I started consuing about the same time cured what ailled me.

thirteen years later the symptoms return if I skip having bowls of high fiber cereal 4 or 5 times a week.

Weary

[Alligator]

Of course. The question is how they got giardiasis. The evidence as near as I can tell is that most got it from dipping their hands in to a bag of gorp offered by someone who has not practiced good sanitation, or sharing half eatened food, or being licked in the face by a giardia carrying, but friendly dog.

Weary

You don't that, I don't know that either. We don't know if they're dipping their hands into the water source either. Hygiene is considered poor all around after all.

As far as being licked in the face by a giardia carrying dog, it's not polite to give tongue on the first date.

[Alligator]

...
The will never be a study to attempt to measure pathogens in backcountry water sources. Sample size will be small, and ability to detect pathogens will vary by ambient temperature, time to get sample to lab and other impossible to control variables. Plus, there would be a tremendous financial burden to complete this test and a catastrophic financial risk should water treatment be determined to be useless.

...

You mean like this one
http://www.whiteblaze.net/forum/arti...97&postcount=1?

Specifically this reference
Open File Report No. 86-404-W. Dept. of the Interior, US Geological Survey, 1986

[SGT Rock]

No, my post referred to the article by Dr. Rockwell, PhD. The part of his article that I am referring too (other than the parts about the Sierra Nevada's which I know you think cannot possibly relate to the AT, we have had that discussion before) are the tests about how many cysts had to be ingested with water before only 30% of the subjects got measurable readings of giardia in their stool - and that isn't even symptoms. And how many cysts are in animal dropping by comparison. And about the part CDC studies of urban population where most people were exposed to giardia without knowing it and the chance of getting measurable giardia cysts was less than 1 in 2 even when the contamination was so bad, and the chance of even having symptoms from it of those contracted was less than 1 in 4, and the same case which found the chance of getting symptoms from water heavily contaminated was 1 in 9. That seems pretty well documented and has nothing to with the Sierra Nevada's - only about how hard it is to actually contract the symptoms when heavily exposed to giardia over a period of time. And about the other things in the article which seemed to be repeated in Musser's book about people getting sick and the source most likely being Eschandria Coli, Camplobacter, Salmonella, etc. and other things in that article about how giardia actually acts. I suppose the one person that represents that less than 1 in 9 that got it, and got it bad would be enough to put a lot of folks off. I got dysentery once and it put me off of ever wanting it again, but I was also drinking bottled water - so I know it was from the bad sanitary conditions where I was at.

Think of this: Field sanitation. In FM 21-10 there are the 5-Fs of field sanitation considerations. Of those five, only one has anything to do with water. And that is what I was getting to when I asked what is the background behind how they actually got it? Think of it this way: Musser's book found that people using filters still got sick while people that didn't ever treat faired better. So that means that the filter is probably not providing any real extra protection, and that the source of infection is something else. Back to the 5-fs:

1. Fingers
2. Feces
3. Flies
4. Foods
5. Fluids

We all know that fingers are a huge problem because backpackers live in less than ideal sanitary conditions. They put their hands where animals have dropped feces. They eat with those same hands. They don't always even realize they could do this. Say a hiker pets a dog that 1 hour ago was just rolling a in a great smell - that smell could be feces which has that 100,000 cysts. A fly could be the transmission from feces surface laid by a sick hiker to your food. Food could be prepared wrong in a container that wasn't cleaned correctly, or water could have other stuff in because it has run off in it from a parking area upstream. None of these cases we talked about confirmed the method of ingestion and most them never even went to find out if it was giardia in the first place. As a scientist you would normally want the method of induction and an actual diagnosis to be able to quantify that case as meaning anything in any real manner wouldn't you? If I said I got demon possessed on French fries and Buddha saved me, you would ask if it really was alcohol that got me possessed or the alcohol that was also there and whether it was really a demon or just a bad drunk. Same thing here - was it really giardia and was it really from the water? No way to know.

With the low amount reporting even symptoms on a thru-hike in Mussler's book, I tend to believe the danger is hype. That same amount of people probably would have gotten something like that even if they had not been hiking and simply living with treated city water.

If the CDC did a study that found less than 1 in 9 got giardia symptoms from water heavily contaminated with regular exposure over a period of time, then it seems that even the passing contact with it over a single liter or two is probably not nearly as scary as people seem to think.

[bailcor]

Am 68 years old and still drinking without filter. Heres and article you can read on it. http://www.yosemite.org/naturenotes/Giardia.htm