Is Aqua Mira effective against Giardia?

[Robert Richey]

A couple of years ago I believed that Aqua Mira drops required four hours to be effective against Giardia when the water was cold or turbid. Because of this factor and the taste issue, I added the Frontier Pro filter to the Aqua Mira, then ditched them both in favor of the Sawyer squeeze filter, which I'm pretty happy with. Are there any current data to indicate that Aqua Mira by itself is or is not highly effective against Giardia within 20-30 minutes? An article by the CDC seems to indicate that it's effective, but it does not specify how much time is required.

http://www.cdc.gov/healthywater/drinking/travel/backcountry_water_treatment.html

[Walter Carrington]

When I last looked into it, I felt Aqua Mira was somewhat in the info they provided. Unless they give the amount of treatment time (vs temperature) for treatment of giardia and cryptosporidium it's useless. My recollection is that you need a higher concentration of AM than normal for giardia and crypto.

Katadyn micropur tablets, when last I looked either the package or website had this treatment info.

Most filters would remove cysts, so when combined with AM or micropur you'd be covered for viruses, bacteria and cysts. The Sawyer squeeze filter seems light, cheap and effective; combine it with chemicals. Amazon has a good price right now.

There may be a Norovirus on the AT in VA this year and was one on the AT in NH and ME last year.

[M B]

The EPA has conservative treatment criteria published for chlorine dioxide, as it is used by municipal water treatment facilities.

It is linear, concentration (ppm) x time (min) for treatment. The published date is in CT tables (conc-time)

For instance, you could have 1 ppm for 40 minutes, that is the same as 4 ppm for 10 minutes.

By my recollection, AM should make a concentration that will deactivate giardia 1000 fold in only a couple of minutes.

The real question is how much do you need, ie how contaminated is your water, how many cysts does it contain?

The military I think, did some testing with AM, and found it not as effective as some treatement methods, but found a ClO2 dioxide tablet the most effective. Go figure. It should be the same thing. Made me suspect the testing was poor .

[steven franchuk]

"The EPA has conservative treatment criteria published for chlorine dioxide, as it is used by municipal water treatment facilities.

It is linear, concentration (ppm) x time (min) for treatment. The published date is in CT tables (conc-time)

For instance, you could have 1 ppm for 40 minutes, that is the same as 4 ppm for 10 minutes.

By my recollection, AM should make a concentration that will deactivate giardia 1000 fold in only a couple of minutes."

Keep in mind that anything corrosive enough to kill viruses, bacteria,and giardia, can also make you sick if you get too much of it.

The EPA sets the requirement for water purification. AM needs to use enough ClO2 to do the job without becoming toxic to people. So you cannot just add more CLO2 to shorten the treatment time. After the two chemicals react you have a solution of part A residue, part B residue, and CLO2. The residue and CLO2 determine how toxic the chemicals are. The time required to treat water is set by the maximum amount that can be safely used without becoming toxic. AM cannot simply increase the dose to shorten the treatment time.

Katadyn has a different chemistry which allows a 30 minute treatment to kill Giardia but requires 4 hours for Cycsts without becoming toxic. Bot AM and Katadyn both uses CLO2 and both are register by the EPA. So both are effective against Viruses, bacteria,Giardia, and Cysts. if you follow the directions correctly you will get clean safe water. But since the two products us different chemistry to generate the CLO2 the time required to do the job is different.

Personally I found I was not always waiting long enough before drinking the water. Never got sick but I don't want to take chances. So now I am using a Sawyer in line filter on my bladder. The filter is instantly effective against Bacteria, Giardia, and Cysts and anything larger, but not viruses. So I also add Katadyn CLO2 tablets to my bladder to quickly kill any bad viruses. It works fast enough on viruses and combined with the filter gives me clean safe water with a minimal wait.

[M B]

AM is supposed to make a 4ppm/liter conc. when directions are followed.
YOU are free to do whatever you want

There is no toxicity known at these low levels
It is prudent not to use 3x the concentration, but there is nothing preventing a person from doing so either.

AM drops are not registered with the EPA.
AM tablets are registered as a water purifier

Micropur tablets are essentially the same as the AM tablets.
Same treatement times as well.
Time depends on ClO2 conc only.

BTW the CT value is 19 for 15C water for 3log deactivation of giardia (1000x)
So in clean 15C water, 4ppm takes……. basically 5 minutes.
AT room temp, more like 2.5 minutes.

1 ppm would take 20 minutes if you chose to use less.
Think you need 4 log, wait longer. That is where 15 to 30 minutes comes from.

Here is the problem. No one knows how contaminated their water is, you only need max wait times, for max contamination, cold, cloudy water.

Most peoople also are not smart enough to be given anything but one direction, that covers any situation they might encounter, even if it is overkill 99.99% of the time.

crypto which just plain takes almost 4 hrs anyway. So, no one worries about it.

That said, I use half the recommended amount when getting water from piped springs on the AT, and wait maybe 5 minutes too.

If I was taking water from a lake , I would use the full amount, and probably wait as long as possible.

If I was getting water that was really nasty, I would use a filter and chemicals. I prefer not to hike where there is not good water though.

[kevin sickles]

It is slowly becoming evident that Giardia infections are caused primarily by bad hygiene not unpurified water.

http://www.rei.com/learn/expert-advice/water-researcher-QA.html

http://pweb.jps.net/~prichins/giardia.htm

[Buck Nelson]

Lots of hikers get giardia from water, and there are numerous studies to prove it.

The "hygiene is a bigger issue" claims sound convincing but they are not backed up by data. If so, I'd like to see the numbers.

Derlet, from the REI article, is a more reasonable skeptic; he says he'd treat all water along the AT, for example.

I've spent a lot of time researching this topic:

http://bucktrack.blogspot.com/2011/03/waterborne-giardia-for-backpackers-no.html?m=1

http://bucktrack.blogspot.com/2012/09/backpacker-giardia-debunking-skeptical_8.html?m=1

[Robert Richey]

Excellent info, all. This reinforces my decision to stick with the Sawyer, along with proper attention to hygiene, on this summer's JMT hike. Whether AM or similar product is also needed in the Sierra where I generally hike seems less certain. I have heard nothing to suggest that viruses are a risk there at this time. Has anyone heard anything to the contrary?

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