The Invisible Threat Beneath Our Feet: Microplastics and Soil Degradation

In recent decades, the unchecked rise in plastic production — now exceeding 348 million tonnes annually — has emerged as a major environmental concern. While much of the global attention has focused on ocean pollution, an equally alarming and often overlooked issue is the accumulation of microplastics (MPs) in our soils, particularly agricultural lands. As the world marks World Environment Day 2025 with the theme "Putting an End to Plastic Pollution", it is vital to spotlight how plastic residues in soil are silently undermining efforts to revive degraded land and ensure food security.‍

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Microplastics — plastic particles smaller than 5 mm — form through the breakdown of larger plastic debris due to sunlight (UV radiation), weathering, and biological processes. These particles, composed of synthetic, water-insoluble polymers, can further degrade into nanoplastics, becoming deeply embedded in soil matrices. Agricultural practices such as plastic mulching, compost and biosolid application, and even atmospheric fallout have made farmland one of the largest repositories of these pollutants. For instance, the use of plastic mulch in some regions soared from 6,000 tonnes in 1982 to over 1.2 million tonnes by 2011 — yet the recycling of such materials remains minimal.‍

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Emerging research shows that microplastics disrupt soil structure, reduce water retention, impede microbial activity, and damage soil organisms like earthworms. These particles clog pores, limit aeration, and interfere with nutrient cycling, directly impacting plant growth. Additionally, MPs can bind with toxic substances such as pesticides, heavy metals, and persistent organic pollutants, further compounding their environmental threat and raising food safety concerns.‍

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One striking study published in Science of The Total Environment (Dainelli et al., 2023) examined the effects of polyethylene terephthalate (PET) and polyvinyl chloride (PVC) microplastics on tomato plants (Micro-Tom). The results were alarming: microplastic exposure reduced fruit yield, with PVC also decreasing fruit weight. Nutritionally, fruits showed higher concentrations of harmful metals like cadmium and nickel, and a decline in beneficial antioxidants like lycopene and phenols — posing significant food safety risks.‍

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Globally, microplastic contamination is no longer limited to oceans or coastal regions. Studies from India, including IIT Bombay and IIT Madras, have found MPs in mountain soils, urban environments, sea salt, drinking water, and even air. A 2024 review in Science estimates that 10 to 40 million tonnes of MPs enter the environment each year. Unlike macroplastics, the damage from microplastics is often subtle but far more pervasive and long-lasting.‍

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As we face increasing threats from land degradation, drought, and biodiversity loss, it is time to recognize that invisible pollutants like microplastics are now central drivers of ecological decline. Tackling this issue requires urgent action: policy reforms, promotion of biodegradable alternatives, improved plastic waste management, and greater public awareness.‍

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The silent accumulation of microplastics in our soils is not just an environmental issue — it is a pressing challenge for agriculture, ecosystem health, and human well-being. As we strive to heal degraded lands, confronting soil plastic pollution must become a global priority.‍

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Putting an End to Plastic Pollution: Uncovering the Threat of Microplastics in Our Soils‍

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As we observe World Environment Day 2025 under the theme “Putting an End to Plastic Pollution,” it’s time to turn our attention to a less visible but deeply pervasive issue — microplastic contamination in soils.‍

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While oceans have long dominated conversations on plastic waste, agricultural lands are increasingly becoming silent victims of microplastic (MP) accumulation. The implications are far-reaching, affecting not only soil health but also food security, crop productivity, and human health.‍

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The Growing Presence of Microplastics in Agriculture‍

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Plastics Europe reports that over 348 million tonnes of plastic are produced annually, a number expected to rise sharply by 2050. Much of this plastic ultimately breaks down into particles smaller than 5 mm, known as microplastics — composed of synthetic, water-insoluble polymers.‍

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In agriculture, plastic mulch is widely used to enhance crop yields. However, improper disposal and degradation have led to long-lasting plastic residues in the soil. These residues fragment further under UV radiation, erosion, and microbial activity, embedding themselves deep into terrestrial ecosystems.‍

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How Microplastics Threaten Soil and Crop Health‍

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Microplastics in soil act as pollutant carriers, binding with pesticides, heavy metals like cadmium and nickel, and persistent organic pollutants — compounds that can severely alter soil chemistry and undermine soil fertility. They clog pores, hinder water movement, and reduce aeration — key processes for healthy plant growth.
Moreover, essential soil organisms like earthworms are negatively impacted, with studies showing physiological stress, growth inhibition, and changes in gut microbiomes. These disruptions ripple through food webs, ultimately affecting plant health and agricultural resilience.

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Scientific Evidence: Microplastics Reduce Fruit Yield and Quality

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A 2023 study by Dainelli et al., published in Science of The Total Environment, found that polyethylene terephthalate (PET) and polyvinyl chloride (PVC) microplastics reduced fruit number and weight in tomato plants (Micro-Tom cultivar) grown under hydroponic conditions.
The study also revealed:

• Elevated levels of heavy metals like Ni and Cd in the fruits

• Reduced concentrations of beneficial nutrients, including lycopene, phenols, and soluble solids

• Serious concerns around food safety and nutritional quality
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India and the Global Picture

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India is not immune. Microplastics have been detected in sea salt, drinking water, and agricultural soils. A 2024 review in Science estimated 10 to 40 million tonnes of MPs enter the environment annually. IIT Bombay and IIT Madras have found MPs in ecosystems ranging from Himalayan soils to dense urban settings.

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Moving Forward: A Call to Action

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As we seek to restore degraded lands and build climate-resilient agriculture, tackling plastic pollution — especially its invisible forms — is urgent. This requires:

• Promoting biodegradable alternatives to conventional plastics

• Strengthening waste management systems

• Enabling science-driven policy interventions

• Raising public and institutional awareness
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Let’s not forget: land degradation today is not only about deforestation or overgrazing — it is increasingly driven by microplastic accumulation. A healthy planet starts with healthy soil.

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#WorldEnvironmentDay2025 #PlasticPollution #SoilHealth #SustainableAgriculture #Microplastics #LandRestoration #FoodSafety #TDU #EcologicalFutures

Shreya Singh
PhD Scholar
Centre for Conservation of Natural Resources

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