Water treatment for blue-green (toxic) algae

The BOTTOM LINE >>>> if you see waters as in the picture below it MAY be a health hazard! NO treatment will provide the water safe so contact should be avoided.

QUICK SUMMARY
Cyanobacteria, formerly called "blue-green algae", are simple, life forms closely related to bacteria. Although they are similar to algae, they are not true algae. Cyanobacteria are found throughout the world in freshwater and marine habitats. However, cyanobacteria "blooms" typically only occur in freshwater.

Nutrient-rich bodies of water such as eutrophic lakes, agricultural ponds, or catch basins, may support a rapid growth of cyanobacteria. When conditions are right, a "clear" body of water can become very turbid with a green, blue-green or reddish-brown growth within just a few days.

Toxic Cyanobacteria
Sometimes cyanobacteria blooms may produce toxins that are potentially lethal to animals, including humans. Cyanotoxins include a diverse range of toxic mechanisms as illustrated in Table 1. Poisoning from nerve toxins can appear within 15-20 minutes after ingestion. In animals symptoms from neurotoxin exposure include weakness, staggering, difficulty in breathing, convulsions and death. In people symptoms may include numbness of the lips, tingling in fingers and toes, and dizziness. Liver toxin poisoning may take hours or days for symptoms to appear. Symptoms of liver toxin exposure include pain, diarrhea and vomiting in humans and death in animals.

Human health risk from exposure to cyanobacteria and their toxins during recreational water use arises through three routes of exposure (WHO):
• direct contact of exposed parts of the body, including sensitive areas such as the ears, eyes, mouth and throat, and the areas covered by a bathing suit (which may collect cell material)
• accidental uptake of water containing cells by swallowing
• uptake of water containing cells by aspiration (inhalation)

It is not possible to determine whether it is producing toxins without special testing. Therefore the State is warning people (and their pets) to avoid contact with surface scums whenever a blue-green bloom is suspected.

This is another site if the above does not answer your questions:
http://www.cdph.ca.gov/healthinfo/environhealth/water/pages/bluegreenalgae.aspx

That blue-green algae is a little too close to my hiking grounds, though downhill from my backpacking grounds. Of course, over the millennia, elk never had a problem before all the herds and whatnot started contaminating the surface water but that's a different fight.

I did a little digging around. It looks like treatment techniques will kill cyanobacteria (blue-green algae) but the toxins they produce will be left. In other words: the treatment is ineffective. Here is a decent source (though focused on Ag not backpacking): http://dnr.wi.gov/lakes/bluegreenalgae/

I wonder how effective activated carbon treatment would be at getting rid of the toxins. Nobody seems willing to sign off on the safety of small scale treatment of water using activated carbon.

Bad water is a huge reason when I hike in agri areas I carry all my water. Better that, than drinking the water :-(

Would digging a gypsy well at least a few feet away, help at all with this issue? I know it's not LNT, but sometimes you might really need some water.

Bringing this thread back from the dead because of the situation in Ohio with Blue-green algae.

Is there an effective treatment to filter/purify the water so the toxins created are removed?

Ben,

Here's an answer for you, 10 months later:

Looking at the structure of those toxins (here's one):

there are so many polar O, OH, OOD, NH2, etc, functional groups hanging off of the carbon chain that it will have pretty high solubility in water. Pure hydrocarbons (benzene, decane, oils, etc) have high affinity for activated carbon and low solubilities in water, so carbon is very efficient and removing them from the dissolved phase. Much less so alcohols, aldehydes, ethers, etc that have polar groups on the hydrocarbon backbone.

A good idea, but not for this class of compounds. The molecules are large so reverse osmosis would work well (that helps sailors much more than backpackers). Distillation would work too, but that requires an awful lot of fuel.

Thanks David!

I thought I had read somewhere that the treatment for cyanobacteria poisoning was dose of activated carbon but perhaps I confusing things. Too bad. It would be interesting to have some more in depth studies done on what those little activated carbon filters treat compared to what is found in backcountry water.

-Ben

I wanted to resurrect this thread, because I filtered some questionable water.  It got me thinking that my filter (MSR Trailshot) that I am probably not filtering out any cyanotoxins.

This is an ever-increasing issue.  Does anyone know of anyone working this?

Thanks

In the end of the day I think it is an insurmountable problem because it is poorly defined.  You can’t have a light, robust filter that universally removes “chemicals” because there are an awful lot of chemicals out there and you don’t really want to remove *all* of them.  It would not be a good water treatment if you remove all of the dihydrogen monoxide for instance.

In the end of the day you just have got to know what you are getting yourself into before you drink it.  I do think activate carbon is underused in the backpacking community because it is hard to guarantee any sort of effectiveness. You are using these carbon molecules to attach to other chemicals such as hydrocarbons.  As the activated carbon attaches to these molecules you loose the ability of that carbon molecule to attach to the next molecule.  As a result activated carbon filters get used up over time and no company will be willing to tell you how effective the filter is (because it is constantly changing.

However, given all those caveats it is one of the few things that will remove some of these nasty chemicals.

I’m really intrigued by the gypsy well idea. But I don’t know if the toxin would migrate through the soil with the water or if it would get filtered out.

The wells in our area are always being monitored for chemicals coming from nearby farm fields and the chemicals that are sprayed yearly on crops and weeds. So they obviously go thru the ground, but it takes a high concentration in order for the chemical levels to rise.

A gypsy hole can’t hurt if that’s your only choice. I would look for a better source. or a water sherpa.

Here’s another intriguing idea, from Wikipedia: “Anatoxin-a is unstable in water and other natural conditions, and in the presence of UV light undergoes photodegradation, being converted to the non-toxic products dihydroanatoxin-a and epoxyanatoxin-a.”

This jives with some state health department websites that say days after the cyanobacteria are gone, the risk is gone.  So something – oxidation, sorption onto soil and/or UV degradation is happening.  So what if you carry a UV Steripen?  Seems to me that someone should test that on a bunch of lab mice and see how their survival differs with and without treatment.

I agree with Ben that activated carbon is very underutilized by outdoors people and yet it is effective at removing many toxic compounds.  Not everything, so no one is going to certify its use against unknown contaminants at unknown concentrations.  Also, you eventually “saturate” the carbon with contaminates and there’s no easy way to tell when that happens.

So, in a pinch?  Run it through any particulate filter you have, leave it in the sun / use UV, run it through carbon (or put a activated-carbon tea bag in it), and boil it.  It will then be safer than it was.  Probably.

That sounds like a great science fair project except that, since it involves the death of vertebrate animals, by ISEF rules it would need to be performed at a USDA inspected research institute.

https://student.societyforscience.org/vertebrate-animals

Then use boneless chickens for the science fair project