The modern world is awash in plastic, and its microscopic remnants are now ubiquitous, from the deepest ocean trenches to the air in our homes. These tiny fragments, known as microplastics, are typically smaller than five millimetres and have become a pervasive contaminant in the global environment. Understanding their origins is crucial to addressing the scale of this problem.
Microplastics originate from a wide array of sources, which can be broadly categorised into two types: primary and secondary. Primary microplastics are those released directly into the environment as small particles. The most significant of these is the laundering of synthetic clothing, which accounts for an estimated 35% of primary microplastics in the oceans. Other major contributors include the abrasion of car tires during driving, responsible for 28% of the total, and the intentional inclusion of microbeads in personal care products, like facial scrubs. The fact that a substantial portion of microplastic pollution stems from these fundamental, everyday aspects of modern life, driving and wearing clothes, underscores that a behavioural solution alone is insufficient. It highlights the critical need for large-scale, systemic technological interventions to address the problem at its source or through environmental remediation.
In contrast, secondary microplastics are generated from the degradation of larger plastic objects, such as discarded bags, bottles, and fishing nets. This process accounts for the vast majority (69-81%) of microplastics found in the oceans. The slow, inexorable breakdown of existing plastic waste ensures that the problem is not static; it is constantly multiplying, with the number of particles in the seas now estimated to be 500 times greater than the number of stars in our galaxy. This dual-origin nature of microplastic pollution emphasises the importance of innovative cleanup methods, such as the one developed by Rajani Srinivasan and her team, which offers a novel approach to large-scale water treatment.
A recent study published in the journal ACS Omega, presents a promising new approach to combating microplastic pollution in water. Led by researcher Rajani Srinivasan, the team investigated the efficacy of natural polymers derived from okra and fenugreek, the same sticky substances responsible for their characteristic "slimy" or "gel-like" textures. Their work builds on earlier findings that these plant-based polymers, specifically polysaccharides, have a natural affinity for microplastics, causing them to clump together and sink. This process, known as flocculation, simplifies the physical separation of plastic particles from water, providing a potentially powerful tool for environmental remediation.
In this next stage of their research, the scientists optimised the process for various water types. They prepared dried powders from the okra and fenugreek extracts, which were then tested on both lab-prepared and real-world water samples. The results were notable, with the plant extracts attracting and removing up to 90% of microplastics in ocean water, freshwater, and groundwater.
A key finding was the superior performance of these natural polymers compared to the synthetic, commercially available polyacrylamide polymer, which is a common agent used in wastewater treatment. The natural extracts proved to be not only highly effective but also biodegradable and nontoxic alternatives. This positions them as a safer and more sustainable option for large-scale application.
The research also revealed a fascinating and crucial detail: the effectiveness of the plant extracts varied depending on the water source. Okra extract performed best in ocean water, achieving an 80% removal rate. Fenugreek, on the other hand, was most effective in groundwater, removing 80-90% of microplastics. A 1:1 mixture of the two extracts was found to be optimal for freshwater, with a 77% removal efficiency. This variability in performance, which researchers hypothesise is due to the different types, sizes, and shapes of microplastics in each water sample, points to the complexity of the problem. It suggests that a single "magic bullet" solution may not be feasible. Instead, a real-world, large-scale application of this technology would likely require a tailored approach, perhaps involving specific blends of plant polymers optimised for the unique contamination profile of a given water source or wastewater facility.
While the okra and fenugreek research offers a promising environmental solution, it prompts a different and highly relevant question about human health: can these same compounds be taken as supplements to remove microplastics from the body? To answer this, it is necessary to first understand how microplastics enter and affect human physiology.
Microplastics enter the human body through three primary pathways: oral intake, inhalation, and skin contact. Oral ingestion is the most common route, with particles found in drinking water (both bottled and tap), seafood, salt, and even sugar. The use of plastic food containers and non-stick cookware can also introduce contaminants into our diet. Inhalation is another significant pathway, as microplastics are small enough to become airborne, carried by dust from urban areas and released from the abrasion of vehicle tires and synthetic clothing. These airborne particles have been detected in both indoor and outdoor air. While less common, smaller particles in personal care products or from materials like phone cases may be absorbed through skin contact, particularly if the skin barrier is damaged.
Alarming new findings suggest that microplastics are no longer merely an environmental contaminant; they are a confirmed part of our "body burden."These synthetic particles have been detected in a diverse range of human tissues and fluids, including the blood, lungs, liver, spleen, and even the brain, testicles, and placenta. The discovery of microplastics in breast milk and meconium, a newborn's first stool, confirms that exposure is not just a lifelong phenomenon but that individuals are "born pre-polluted."
Research on the health impacts of microplastics on humans is still in its nascent stages. However, a growing body of evidence from animal and cellular studies suggests potential links to oxidative stress, chronic inflammation, immune dysfunction, metabolic disorders, and even neurotoxicity. A large-scale review by scholars at the University of California, San Francisco, concluded that microplastic exposure is suspected of harming reproductive, digestive, and respiratory health and may be linked to certain cancers. Furthermore, one of the first human studies to directly examine the risks found that patients with microplastics in arterial plaque had a higher risk of heart attack, stroke, and death.
A critical aspect of this potential toxicity is that microplastic particles themselves may not be the sole cause of harm. Their large surface area allows them to act as "vectors," adsorbing and concentrating other environmental pollutants, such as heavy metals and persistent organic pollutants. This means that microplastics can introduce a complex chemical load into the body, further exacerbating potential health risks. The total health impact is a combination of the physical presence of the plastic and the chemical contaminants it carries. This makes the problem more complex and reinforces the urgency of studying their long-term effects.
The intuitive leap from cleaning water to cleaning the human body with the same substances is a logical one, but a critical analysis reveals a fundamental flaw in the analogy. A water filter is an inert physical system, while the human gut is a dynamic, biologically active environment. The biological fate of the okra and fenugreek polysaccharides is entirely different from their physical function in water.
In the ACS Omega study, the polymers are used as flocculants because their long, sticky chains remain intact, binding to microplastics and causing them to aggregate. When these same polysaccharides are ingested, they are largely resistant to initial digestion in the stomach and small intestine. This resistance means they do reach the colon intact, which might initially seem to support the supplement hypothesis.
However, upon reaching the colon, a different process unfolds. The gut is home to a vast and diverse community of microbiota that are equipped to break down these complex carbohydrates. In vitro studies show that the polysaccharides from okra are significantly degraded and utilised by human gut microbiota, a process that fundamentally alters their structure. During this faecal fermentation, the molecular weight and viscosity of the polymers significantly decrease. This is the exact opposite of the aggregation effect needed to trap microplastics.
The irony is that the very process that makes these compounds beneficial for human health, their fermentation into short-chain fatty acids like acetic and propionic acid, is the same process that dismantles their physical ability to act as flocculants. The biological environment of the gut actively breaks down the long, sticky chains that are essential for the water-treatment mechanism to work. Therefore, taking these compounds as a supplement for the specific purpose of removing microplastics from the body is not a scientifically valid strategy. The mechanism does not translate from a passive, physical system to an active, biological one.
Based on the current body of scientific evidence, the assertion that taking okra or fenugreek supplements will remove microplastics from the body is not supported. The proposed mechanism for water treatment is biologically incompatible with the processes that occur within the human digestive system.
Furthermore, it is important to exercise caution with any supplement. While fenugreek is generally considered safe when taken in powdered seed form for up to three years, it is not without risks. It can cause side effects such as diarrhea, stomach upset, and bloating. A more significant concern is its potential for moderate to severe interactions with common medications. Fenugreek can slow blood clotting and dangerously lower blood sugar, making it a serious concern for individuals taking blood thinners like Warfarin or diabetes medications.
Instead of pursuing an unproven supplement-based strategy, a more effective and evidence-based approach is to leverage the proven power of general dietary fibre. Research indicates that dietary fibre acts as a natural barrier in the digestive tract, trapping microplastics and facilitating their elimination from the body before they can be absorbed into the bloodstream. Studies have demonstrated that individuals who consumed at least 30 grams of fibre per day showed a significant reduction in microplastic absorption compared to those with lower fibre intake. The binding properties of fibre, found in fruits, vegetables, whole grains, and legumes, are what prevent microplastics from crossing the gut barrier.
In conclusion, the research on okra and fenugreek is a remarkable scientific achievement, offering a nontoxic and biodegradable solution for a critical environmental problem. It represents a major step forward in the effort to clean our water supplies. However, the path to addressing the confirmed presence of microplastics in our bodies is not a simple one-to-one translation of this environmental solution. The evidence suggests that a more holistic and proven approach is necessary. By actively reducing daily exposure to plastic and by supporting our body's natural excretory functions through a healthy, high-fibre diet, individuals can make informed and effective choices to mitigate their own microplastic burden.
"Research Update: Okra, fenugreek extracts remove most microplastics from water
The substances behind the slimy strings from okra and the gel from fenugreek seeds could trap microplastics better than a commonly used synthetic polymer. Previously, researchers proposed using these sticky natural polymers to clean up water. Now, they report in ACS Omega that okra and/or fenugreek extracts attracted and removed up to 90% of microplastics in ocean water, freshwater and groundwater.
Rajani Srinivasan and colleagues have been exploring nontoxic, plant-based approaches to attract and remove contaminants from water. In one set of lab experiments, they found that polymers from okra, fenugreek and tamarind stick to microplastics, clumping together and sinking for easy separation from water. Srinivasan spoke about successful demonstrations of the plant extracts in freshwater and ocean water at ACS Spring 2022, a meeting of the American Chemical Society. In this next stage of the research, they have optimized the process for okra and fenugreek extracts in various types of water.
To extract the sticky plant polymers, the team soaked sliced okra pods and blended fenugreek seeds in separate containers of water overnight. Then, researchers removed the dissolved extracts from each solution and dried them into powders. Analyses showed that the powdered extracts contained polysaccharides, which are natural polymers. Initial tests in pure water spiked with microplastics showed that:
One gram of either powder in a quart (one liter) of water trapped microplastics the most effectively.
Dried okra and fenugreek extracts removed 67% and 93%, respectively, of the plastic in an hour.
A mixture of equal parts okra and fenugreek powder reached maximum removal efficiency (70%) within 30 minutes.
The natural polymers performed significantly better than the synthetic, commercially available polyacrylamide polymer used in wastewater treatment.
Then the researchers tested the plant extracts on real microplastic-polluted water. They collected samples from waterbodies around Texas and brought them to the lab. The plant extract removal efficiency changed depending on the original water source: Okra worked best in ocean water (80%), fenugreek in groundwater (80-90%), and the 1:1 combination of okra and fenugreek in freshwater (77%). The researchers hypothesize that the natural polymers had different efficiencies because each water sample had different types, sizes and shapes of microplastics.
Polyacrylamide is currently used to remove contaminants during wastewater treatment, but the researchers say that okra and fenugreek extracts could serve as biodegradable and nontoxic alternatives.
"Utilizing these plant-based extracts in water treatment will remove microplastics and other pollutants without introducing additional toxic substances to the treated water," says Srinivasan, "thus reducing long-term health risks to the population."