Suddenly surrounded by giants, I stared up at them as I spun around and around. Towering over me, they quietly stood in row after row that seemed to go on forever. Slender stalks supported their yellow-fringed faces bobbing in the breeze. This happy army of sun soldiers looked down at me, a two-legged interloper in their sea of yellow. I’d left everything I knew behind and was now in an enchanted land where flowers grew bigger than me. Being a grownup seemed overrated anyway. I decided in that moment it’s best to never grow up, unless of course, you’re a sunflower...
Love at first sight
When I was seven years old, my parents decided we needed to live closer to nature. Several years earlier, we had moved from one of the largest cities in the nation to a small town. Now we continued our quest to a house in the country. The day I stumbled into a grove of sunflowers changed me forever. I felt like Alice in Wonderland. Their enormous, shaggy blossoms signaled hope that, in life, the miraculous can appear unexpectedly.
I shared my sunflowers with pollinator bees and seed-loving birds. I sketched them. I made finger paintings of them. I crafted yarn collages using multiple hues of yellow, brown and green. I talked to them, studied them, identified with them. I grew sad as these annuals succumbed in the late Fall, and thrilled to their rebirth in Summer.
How could I possible love them more? Recently, I discovered that these citadels of color take on some of the most lethal pollutants on Earth. Sunflowers remove toxins such as heavy metals and radioactive waste from our environment. By storing these contaminants in their tissues, they help cleanse the Earth. (1)
Not just a pretty face
Sunflowers belong to a class of plants called phyto-remediators. There are different types of these plants, which are classified further based on how they take up the pollutant. That is, do they chemically alter it, actually break it down, or just store it in their tissues? The list of plants is impressive.
Each plant varies as to what type of contaminant it is best suited to act on. The plants come in all shapes and sizes: Big and small, low-lying and tall, soil-bound and water-floaters, the diverse list includes Black Willow trees, Common Wheat, Fairy Moss, Water Lettuce, Herb of Grace, Buttonbush, and Duckweed — to name a few. (1, 2)
Sunflowers are classified as hyper-accumulators. They are not able to break down contaminants, but can store them in their tissues. That means the sunflowers, themselves, must be disposed of as toxic waste. But not only can they grow on contaminated soil, they can effectively package contaminants. They can reclaim the land for re-use to live on and to grow plants including healthy, edible crops. (3)
Floating adrift with purpose
Imagine webbed blankets of sunflower blossoms floating on the sea, their stalks reaching down into the water, singing their siren song to lead, copper, chromium, zinc... These blankets do exist and are currently used to help clean spills and contaminants in water. (4)
Imagine the most contaminated areas on Earth — like, the fields around Chernobyl — populated acre upon acre with an army of sunflowers. These fields did exist in the 1990s. Because of their success in decontaminating the soil around Chernobyl, sunflowers were also planted around the Fukushima nuclear disaster site.
Unfortunately, the Fukushima remediation attempt failed. Why? The particular strain of sunflower used was not the best for taking up the specific toxins that were polluting the soil. (5)
How much do we know about this?
Phyto-remediation is a young, albeit growing science. First introduced in 1983, it’s now also a growing industry worldwide. (3) We need more research and a better understanding of the process, especially its full impact on the environment.
For example, what if the best plant to remove a particular toxin is non-native? Or how will planting a disproportionate number of even native plants impact the ecosystem? How does the presence of a hyper-accumulating plant impact herbivores? Or what about pollinators?
One thing we do know, is that bees can sense if a plant has elevated levels of nickel in its nectar and are they’re much less likely to pollinate it. The bees don’t like the taste, so they’ll move on to a plant that tastes better. (6)
Unfortunately, we also know bees are less persnickety when it comes to aluminum. A plant’s nectar can reek of aluminum, yet bees will get to work anyway. So does that mean the aluminum is re-introduced into the food chain? (6)
There have also been instances where the hyper-accumulating plants prematurely died. Why? Simply because the contamination levels in the soil were just too high for them. Phyto-remediation works best in mid to low level contamination. (7)
Where does that leave us?
Can we study nature’s remedy and create some sort of artificial equivalent? One promising area being explored is the potential for transgenic plants — that is, plants with altered DNA — to be bred for specific clean-ups. (8)
So there’s potential for a low-cost, effective means to start cleansing our environment. There’s also still a lot we don’t know. But just knowing that nature has a process already in place to help remove contamination is nothing short of a miracle. Phyto-remediation is encouraging evidence of the resilience of nature. It can motivate us, and maybe point us in the right direction toward helping heal our planet.
Video courtesy of video.net
Sunflower blossom photo courtesy of Laura Gilchrist on Unsplash.com
Field of sunflowers photo courtesy of Stefano Zocca on Unsplash.com
Bees on sunflowers photo courtesy of Audrius Sutkus on Unsplash.com
Sunset over sunflowers photo courtesy of Jeb Buchman on Unsplash.com
Phytoremediation Resource Guide, EPA, Solid Waste and Emergency Response (5102G), June 1999, www.epa.gov/tioclu-in.org
Phytotechnologies: Useful Plants, a database; Ilaria De Angelis e Barbara Di Fabio, Laura Passatore, Angelo Massacci, and Michele Mattioni; REMIDA: Remediation, Energy Production & Soil Management
Status of Phytoremediation in World Scenario, Parul Sharma, Sonali Pandey. International Journal of Environmental Bioremediation & Biodegradation, 2014, Vol. 2, No. 4, 178-191
Sunflower: A Potential Crop for Environmental Industry; M.N.V. Prasad; Department of Plant Sciences, University of Hyderabad, India; May 2007
Berkeley.edu Bloom of the Week; Josh Vandenbrink; https://nature.berkeley.edu/blackmanlab/Blackman_Lab/Lab_News/Entries/2013/2/18_Bloom_of_the_Week_-_Phytoremediation_with_Sunflower.html
“Effects of nickel and aluminum in nectar on foraging behavior of bumblebees,” George A. Meindle and Tia-Lynn Ashman, University of Pittsburgh, Department of Biological Sciences, Pittsburgh, PA 15260, USA
“An Overview of the Phytoremediation of Lead and Mercury,” Jeanna R. Henry, Fellow; National Network of Environmental Management Studies (NNEMS); May-August 2000; Prepared for U.S. Environmental Protection Agency Office of Solid Waste and Emergency Response Technology Innovation office Washington, D.
“Environmental cleanup using plants: biotechnological advances and ecological considerations,” Elizabeth AH Pilon-Smits , John L. Freeman, The Ecologoical Society of America, May 2006, https://doi.org/10.1890/1540-9295(2006)004[0203:ECUPBA]2.0.CO;2
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