Microplastics have been found everywhere on earth, from the top of Mount Everest to the deep sea. In early 2022, the tiny plastic fragments were detected in human blood for the first time, with scientists finding them in almost 80% of the people tested.
With this problem at hand, Dr. Rajani Srinivasan, a professor of chemistry at Tarleton State University in Texas, wanted to come up with a solution. Starting in 2012, she and her students began experimenting with natural flocculants, or substances that cause microplastics and other suspended solids to clump together and sink, where they can be extracted.
A toxic feedback loop
No bigger than five millimeters, microplastics are minuscule fragments that splinter off everyday plastic objects like shopping bags, water bottles, or PVC pipes. They get swept into the water supply or seep into it through products such as toiletries and cosmetics.
To rid the water supply of microplastics, many water treatment facilities use synthetic chemical flocculants. Yet, these chemicals themselves may be toxic, replacing one bad agent with another.
“If we are removing microplastics and in turn adding some materials which are toxic to us, it does not make a lot of sense,” says Dr. Srinivasan. So, she set out to replace synthetic agents with plants and spices.
Using everyday ingredients
Growing up in southern India, Dr. Srinivasan was accustomed to okra served in bhindi masala, tamarind in vegetable curry, and the aroma of dried fenugreek leaves. She took these staples from her diet and started testing different concoctions with her students at their lab in Stephenville.
In March 2022, at the American Chemical Society’s spring meeting, Dr. Srinivasan presented their successful findings. Carbohydrates drawn from okra and tamarind in equal parts created a flocculant that clumped together microplastics and allowed the team to remove the particles from drinking water.
In addition, a mixture of carbohydrate extracts from okra and fenugreek worked to rid microplastics from ocean water. These results could be the solutions for cleaning both consumed water and polluted marine ecosystems.
Scaling the method
While these plant-based combinations are ready for water treatment plants now, the research has yet to be published in a peer-reviewed journal, and there are plenty of licensing hoops to jump through. However, Dr. Srinivasan is already working on ways to quickly scale her team’s process into large-scale production.
Partnering with the High Plains Water District, located in Lubbock, Texas, Dr. Srinivasan is testing how to remove contaminants from the Ogallala and Dockum aquifers. Known to contain arsenic, a mineral associated with cancer, the team is experimenting with several forms of natural flocculants in the Dockum aquifer.
A recipe for clean water
The mixture to clean drinking water calls for one gram of Dr. Srinivasan’s carbohydrate concoction per one liter of water. With many major municipal water operations treating tens of billions of gallons annually, it is an accessible solution and one that is sustainable and good for the planet too.
Much like how corn production shot up dramatically after ethanol standards were adopted, it’s possible that widespread acceptance of this new solution could do the same for okra, tamarind, and fenugreek. Further diversifying crops has the potential to help farmers turn away from monocropping practices, which would also help improve soil health.
Okra, the flowering fruit that most people assume is a vegetable, used most commonly in cooking to thicken sauces, could be the secret ingredient to overcoming the world’s plastic problem. Thanks to a young research team and Dr. Srinivasan, the okra concoctions can possibly further ignite regenerative agriculture practices and clean water around the globe.