Fight The Good Fight: How Plants Can Clean Soil

Sunflowers field sun

Phytoremediation. Big word, big solution.

What is it? Phytoremediation is essentially the use of plants for cleaning damaged soil.

Pish-posh, you say. Soil is dirt. Who cleans dirt? Anyone who’s wary of heavy metals in the ground, that’s who, particularly those behind industrial ground reclamation projects. Heavy metal — it’s not just something teen boys blast on their MP3 players.

Recent “metal” news on rice, for instance,  has been alarming. Long-known to be one of the front-runners in pesticide-contaminated foods, it turns out rice loves to clean soil too, and that’s not so good for the human bellies it winds up in. Your rice might be extracting all kinds of fun things, like arsenic, cadmium, and even a little lead — but that’s okay, because hey, everyone needs some heavy metal in their diet, right? Zoinks! Maybe not.

So enter phytoremediation, a relatively new science. In the ‘90s, we learned that there was a lot of potential in turning to nature to clean nature up. The biggest experiment happened in Chernobyl.

Thriving in the aftermath

As I write, the 28th anniversary of Chernobyl has just passed. On April 26, 1986, the nuclear plant blew, changing life as they knew it. Some 350,000 people would be evacuated over the 14 years following. Even today radiation levels keep the Exclusion Zone in place, but now it’s fallen just enough for scientists and disaster tourists to make short trips.

Where trees were once turned reddish-brown and landscape showed ill effects from the radiation, nature is beginning to thrive, as this 2011 slideshow depicts.

If nature can come back from that, it can come back from a whole lot less.

What goes up must come down

I’m sure some folks like to think of pollution as something that just floats up in the air and gets stuck in the atmosphere, like a helium-filled balloon hanging out on a ceiling. But what goes up must come down, and this means the millions and billions of aerosols generated by pollution eventually flutter down to Earth, landing on topsoil.

The upside to this is, pollution’s usually only found in the top meter, or three feet, of soil. You don’t need some 60-year old tree to suck those heavy metals and pollutants out of the ground. Fortunately, most of us live in relatively healthy situations and whatever surface contaminants do exist tend to be something that’s within safe levels whatever our age, gender, or health level.

Heroes of the underground

Still, we’re becoming more aware of ground pollutants, and it can’t hurt to put in practice at home what’s working in some of the most contaminated sites around. After all, you might be surprised at what some of the most effective phytoremediation plants are.

Take, for example, the lovely sunflower plant. Yes, that big, beautiful sunshiny looking plant thinks pollution makes good eatin’. Check this out.

In February 1996, Phytotech, Inc., a Princeton, NJ-based company, reported that it had developed transgenic strains of sunflowers, Helianthus sp., that could remove as much as 95% of toxic contaminants in as little as 24 hours. Subsequently, Helianthus was planted on a styrofoam raft at one end of a contaminated pond near Chernobyl, and in twelve days the cesium concentrations within its roots were reportedly 8,000 times that of the water, while the strontium concentrations were 2,000 times that of the water. Read the whole article here.

Another famously fiending metal-eating plant is the popular geranium. I recently told you about its ability to fend off pests and insects, but now it’ll chow down on your heavy metals too? Is there nothing it can’t do?

But wait! There are more! Dutch scientists went to work exploring the phytoremedial qualities of a number of plants, and the big winners in the end were the lowly pennycress and willow. If you’re planting them along waterways, things like grasses, alfalfa, poplar, and willow can do wonders cleaning up the water too.

Plant Tomorrow’s Solution Today

These processes don’t transpire overnight, like the quoted passage above with sunflowers-on-rafts-in-Chernobyl-ponds states. There’s a saturation point the plants reach annually, and some cleanups can take 10 to 20 years.

If you’re looking to keep your yard and grounds healthy in the coming years, you might want to learn more about phytoremediation and what plants can do to keep your yard’s heavy metal count at a minimum. There’s no indication the average Joe has anything to worry about at all, but if you’re like me, the old “it can’t hurt” adage about planting a few heavy-metal-chomping plants in your yard doesn’t sound like a bad idea at all.

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