Okra Microplastics to remove microplastics from the ocean
Catherine Stone discusses a recent discovery which indicates Okra could be used as a more sustainable way to remove microplastics from the ocean
There may now be a safe, sustainable way to filter microplastics from water at treatment plants using the vegetable okra, providing new hope in the mission to contain this damaging pollution that has become a pervasive and exponentially growing global challenge.
Microplastics are the tiny pieces of plastics from the degradation of synthetic textiles, packaging and other plastic products of the 400 million tons of plastic that is produced annually, according to research by Nature. Since the explosion in plastic production in WW2, on average only 9% of all plastic has been recycled and 12% incinerated, meaning 89% of all the plastic ever produced still exists in the world as waste. This is largely washed into the oceans from rivers and accumulating in marine food chains as microplastics. They have become a ubiquitous part of our physical environment, and have been found in pristine locations from Mount Everest to the Marina Trench.
Scientists estimate humans take in tens of thousands of microplastics particles every year through inhalation and ingestion through food or water. The health effects on the human body are still not well understood but dangers include the transmission of absorbed pollutants from the environment and cell damage caused by nanoplastics (smaller than one micrometre). Recent research from the Free University of Amsterdam has even found microplastics in the human bloodstream. This risk can be mitigated by removing microplastics from drinking water at water treatment plants.
A recent study by Dr. Rajani Srinivasan at Texas’ Tarleton State University has tested natural methods of filtering microplastics from water with biopolymers and concluded that Okra polysaccharides are the most effective solution. The research was presented at the spring meeting of the American Chemical Society in March. The team’s previous research had focused on removing textile-based pollutants using biopolymers from food-grade plant extracts, finding that they have the appropriate properties to capture pollutants.
Currently municipal water treatment plants add chemical flocculants, such as the fossil-fuel based polyacrylamide, that form clumps which particles stick to. However, these chemicals can pose toxic health risks under certain conditions.
Okra polysaccharides paired with fenugreek were effective at filtering seawater, while okra and tamarind worked best for freshwater. Under different tests, okra performed either as well or better than polyacrylamide. The next phases of the study hope to identify the optimal ratios and combinations of plant-based flocculants to remove different types from ocean, estuary, fresh and ground water.
The use of these biopolymers do not require any changes in water treatment facilities, therefore it could become the industry standard. This potential solution will have to be commercialised on an industrial scale in order to manage the steeply worsening problem of microplastics, which is rapidly becoming a serious public health hazard as well as an ecological crisis.
