We know to put a clear plastic bag on tree branches to collect clean drinking water.

But what happens to that water if you harvested the water from a toxic plant, like oleander or mountain laurel (Kalmia spp)? Is the water contaminated with the toxins, or is it not an issue?

Sue

I would think that it could potentially be toxic as well. I know some plants have the toxin on their surface, which could easily contaminate the water...

Interesting question tho... hmmm....

Contact contamination is likely with plants whose toxins are located on or near the exposed surfaces. This method would most certainly be problematic with plants such as Poison Ivy, as it would be nigh impossible not to contaminate the plastic with the surface toxins these sort of plants naturally exude. Plants who's primary toxicity is due to ingestion might be less risky, but a lot of care would need to be exercised not to expose the plastic to the inner parts of any of the plant. It would be far more desirable to create a reflux chamber whereby the evaporated water the plant exudes would be channeled to a secondary chamber that would isolate any direct contact from the plant material and allow for condensation and collection in a manner physically isolated from the plant material, similar to how a still functions. A field expedient version might be a bit difficult to properly construct, but the theory is sound, and a little "Macgyver" creativity could produce adequate results.

Per the HoodsWoods DVD"s toxicity will be carried over to the
recovered water.

Only in the event of direct contact contamination. The indirect method could be used to isolate the toxins from the condensate.

It is not an easy task, but it can be done.

Okay, I understand.

Thanks!

Sue

I know Les Stroud mentions it in his book. (As in, "do not attempt transpiration on poisonous plants").

I know I've read it elsewhere also, either in the standard Army Survival Manual or some such "comprehensive" tome.

Time to bring out the DVD again I guess but IIRC it had more to do with the volatility (?) of the toxic compounds. Direct contact was not the issue, toxicity was carried with the water vapor.
If that is the case then using toxic plants in a solar still would not render the product safe to drink.

Perhaps filtering the product thru a charcoal water filter might work but i don't think I want to be the one testing it.
How often will you find ONLY toxic plants to use in your water recovery/distillation process?

This was one of those questions that pops up while I'm driving endless miles in the dark.

"How often will you find ONLY toxic plants to use..."

Stranded in a jungle of oleander bushes... what a nightmare THAT would be!

Thanks for the info, guys!

Sue

Yes, as in a solar still. The volatization of the toxic compounds would only be a factor if the condensation point was identical to that of water, in which case a reflux chamber could be added, if you were really worried about it. I think you'll find that most of those compounds don't volatize very well (or the plants would have a tough time keeping their production rate up) at ambient temps, and will either recondense at a higher or lower temp, thus making it possible to isolate them in the condensate line from the water.

Like I said, it wouldn't be easy, but it can be done. We were isolating alchohol from water in high school. How hard can it be?