Water, Water, Everywhere... Is it Safe to Drink?

Water is critical to life, but it's also potentially deadly. According to the Centers for Disease Control, contaminated water killed over 6,000 people in the US alone in 2023. In this video, we are going to take a look at some very low-tech and primitive methods for taking contaminated swamp water, making it crystal clear, and perfectly safe to drink. I've got behind me a jar that is filled with some pretty nasty swamp water; there's actually I can see bugs swimming around in this, there's all sorts of little algae floating around. There's cattle in this pasture that are alongside the creek, so I'm sure there's bacteria and all sorts of nasty stuff in this water. Today, we're going to use plants to filter this water into what is hopefully going to be pure, safe drinking water. Stick around. What we're going to do today is cut a long section of grapevine and we're going to set up a siphon in this jar out of this jar into another clean jar, and then we're going to sample both of these waters, send them off to a lab, and get the results back to see if this grapevine is actually able to filter out all of the bad stuff in this water that would make us sick.

I. Setting Up the Grapevine Filter

If you're going to give this a try, there's a couple of things you need to keep in mind, especially in the southern forest. There are a variety of vines; it's not just grapevines out here, there's poison ivy, there's trumpet creeper, Virginia creeper, there's cross vine, there's all kinds of different vines, so make sure that you're getting the right one. **You definitely do not want to try this with Poison Ivy**. When I'm cutting these things, I'm going to keep tabs on the orientation of the vine. Water in these plants flows from the ground to the leaves, and I want to maintain that orientation, flowing from the uphill side or the dirty water to the clean water bucket. I have no idea if that makes any difference at all, but I think that it probably would, so we're going to give it a try. Now, when you cut a grapevine or any woody plant, the **xylem** when it's exposed to air starts to close immediately, kind of as a self-preservation mechanism for the plant. And so what I've done to counteract that is just bring a jar of water out here, so when I cut this I'm just going to immediately stick the cut end in this jar of water to keep that xylem open and get a better flow through our filter. Pretty much immediately you're going to see water start to drip out of the bottom of these vines. Now, I've got a jar here that's been washed and triple-rinsed to collect this water, and then we'll send it off to the lab to get it tested. Now, because I don't know what's floating around out here in the air and I don't want our sample to get potentially contaminated with who knows what falling into this, I've just got a clean cotton cloth that I'm just going to wrap around here and just try to keep things somewhat standardized. So we'll leave this like this, come back in a couple hours, take our samples. We'll take one out of here, we'll take one out of this jar, send it off the lab, see what we got.

II. Setting Up the Cypress Filter

While this grapevine is filtering, I'm going to set up another filter using a branch off of a cypress tree. We've got a piece of a cypress branch here. Now, I'm not sure if the orientation makes any difference at all, but because water usually flows from the roots to the leaves, I'm going to keep that same orientation in this branch. So this is the side that was towards the tree, this is the side that was out towards the tip of the branches, and so this is the side that's going to go into our bottle to form our filter. Now the first thing we need to do is strip off the bark. Now we'll just need to trim this to fit in our bottle. Just to make sure that we don't get any seepage from around the side to mess up our test results, I'm going to go ahead and just seal it with some tape. And now we'll just cut the remaining bit off.

III. The Science Behind Xylem Filtration

While we're waiting on these filters to do their thing, I want to explain the principles behind this. **Xylem tissue** in woody plants is part of the vascular system and its primary function is to move water and nutrients from the roots to the leaves of the plant. And because this tissue is made up of individual cells, it can't form just one continuous tube from the roots to the leaves. Instead, where these cells overlap, the water has to move through a **membrane** from one cell to the other, the pores of which just happen to be small enough to filter out bacteria. What spawned this whole idea was a **study done at MIT** where they showed that the xylem tissue in the sapwood of **pine trees** would effectively filter out all detectable bacteria from contaminated water. I thought that was pretty cool so I wanted to try it myself using different plants. It's my understanding that the reason they use pine trees is because the xylem tissue tends to be a little larger so you can get a little bit better flow, and the xylem cells are pretty short so you can utilize a short section of pine branch and still get this filtering activity, meaning that you're not cutting the top and the bottom off of a single cell and just having one tube that runs right through without having to go through a membrane, which is what is actually doing the filtering. This is one of the reasons why I cut my grapevine so long is because I wanted to be sure that the water had to not only flow through the xylem cell itself, but from one xylem cell through the membrane to the next xylem cell, and that membrane is where the filtering is actually taking place.

IV. Lab Results and Taste Test

It's been a couple hours and we've got enough water in our jar to get a sample to send to the lab. Just visually looking at this water, it looks perfectly clear and clean, but to be 100% sure there are no nasties in this, we're going to send this off to the lab and get a water analysis on it and see what comes back. It's been 48 hours and we finally got our lab results back. I sent two samples: one from the dirty swamp water jar here, and one that was filtered through the grapevine. I didn't test the water that came through the cypress because the tests were relatively expensive and MIT's already done extensive studies to show that it works.

Results for *E. coli*

• **Raw Swamp Water:** 43.6 MPN (Most Probable Number), which is basically the same as colony-forming units.
• **Grapevine Filtered Water:** Less than one, meaning *E. coli* was undetected.

The fact that there was *E. coli* detected in the swamp water and there was none detected in the sample that was filtered through the grapevine is very encouraging. I think something as low-tech as is cutting a couple of grapevines, sticking them in some dirty water, and getting pure, clean water out the other side is pretty damn amazing. It's my understanding that these filters will **not filter out viruses**, but I'm not sure how prevalent viruses are in our water anyway, so I'm not even sure that that's a problem that you need to worry about.

Taste Comparison

I did a little taste test on the water that was filtered through the xylem tissue of the cypress tree and the water that was filtered through the grapevine. First off, there's no detectable smell difference between the two. The water from the cypress tasted like pure water; it tastes like water you would get out of a bottle. No flavor that I can detect, it's very good. The water that came through the grapevine, I'm picking up a very slight, maybe almost like a chlorophyll almost, which makes sense because if you scrape the outer layer off the grapevine bark, it is green under there. I think because I didn't strip the bark off the grapevine, maybe a little bit of that is just making its way into the water, but it's not off-putting or anything like that. It's just a very, very slight chlorophyll flavor, kind of like if you just took a piece of grass and put it in your mouth and chewed on it a little bit. The test that was run on this tested only for *E. coli* bacteria. The presence of *E. coli* bacteria in your water is an indicator that there could be potentially harmful bacteria in the water.

V. Takeaways and Best Practices

Of course, this is just one test, and in order to say something definitively, you'd have to run a whole bunch of tests and probably control for variables a lot better than I did. I just wanted to run a very simple, kind of rough test here just to see what happened. I would encourage you to go out and try this on your own. It's very easy to do, it's something that you can do with materials that you probably have close at hand. I've done this multiple times with multiple different species at different times of the year under different weather conditions, and I can tell you for a fact that the **weather has an impact on your flow rates**, and the **health of the plants has an impact on your flow rates**. For example, if you do this with a vine that is water-stressed, let's say in a drought, you're probably not going to get as good a flow as you've seen here. The takeaways are to use **healthy plants** that are actively growing and actively transporting water from their roots to their leaves. If you do that, then you can get a good flow and actually have a pretty effective water filter using these very primitive and basic methods.