World Soil Day 2025
Micro- and Nanoplastics (MNPs) in Soil Environments
Soils are among the most complex and valuable components of terrestrial ecosystems. They sustain plant productivity, regulate water dynamics, support nutrient cycling, store carbon, and host a diversity of organisms. Through these functions, soils have an important role for food security, climate regulation, and ecosystem resilience. Despite their central role, soils are increasingly exposed to multiple anthropogenic pressures, including intensive land use, chemical inputs, climate change, and emerging forms of environmental contamination. One such emerging concern is the presence of micro- and nanoplastics (MNPs) in soil environments.
World Soil Day offers an important opportunity to highlight not only the essential functions of soils, but also the growing challenges that threaten their long-term integrity. Micro- and nanoplastics represent a relatively recent but increasingly recognized pressure on soil systems, with potential implications for soil functioning, agricultural sustainability, and human well-being.
Growing Presence of Micro- and Nanoplastics in Soils
Micro- and nanoplastics originate from a wide range of human activities and enter soils through agricultural practices, urban influences, atmospheric transport, and land-based management of organic materials. Once introduced, these particles may remain in soils for extended periods due to their resistance to degradation. Their persistence allows them to interact continuously with soil components, including minerals, organic matter, microorganisms, and plant roots.
Unlike many traditional soil contaminants, micro- and nanoplastics are highly heterogeneous. They vary in size, shape, polymer composition, and chemical additives, resulting in diverse behaviors within the soil environment. Smaller particles, in particular, have a greater potential to interact with biological structures and to move within the soil profile. This diversity complicates predictions of environmental behavior and increases uncertainty regarding long-term consequences.
Effects on Soil Physical Properties
Soil structure plays a fundamental role in determining soil health, influencing aeration, water retention, root growth, and microbial activity. The presence of micro- and nanoplastics has been shown to alter key physical properties of soils, including aggregation, bulk density, porosity, and water-holding capacity. Even moderate changes in these properties can have cascading effects on soil processes.
Changed aggregation may influence soil stability and susceptibility to erosion, while changes in porosity can affect gas exchange and water availability. In agricultural systems, these structural changes may reduce the efficiency of water use and nutrient uptake by crops, thereby affecting productivity. Over time, such modifications can weaken the capacity of soils to buffer environmental stressors and maintain their multifunctionality.
Interactions with Soil Organic Matter and Nutrient Cycling
Soil organic matter is central to nutrient availability, carbon storage, and microbial activity. Micro- and nanoplastics can interact with organic matter through physical and chemical associations, potentially modifying its distribution and stability. These interactions may influence the availability of essential nutrients, including nitrogen and phosphorus, and alter nutrient cycling processes.
Changes in nutrient dynamics can have direct consequences for plant growth and soil fertility. For example, reduced nutrient availability may necessitate higher fertilizer inputs, with associated environmental costs. Conversely, altered nutrient retention could lead to localized accumulation or imbalance, affecting both crops and soil organisms. Understanding these interactions is therefore critical for sustainable soil and nutrient management.
Impacts on Soil Biota and Ecosystem Functioning
Soils are living systems, shaped by the activity of microorganisms, fungi, and soil fauna. These organisms drive key ecosystem processes, including organic matter decomposition, nutrient mineralization, and soil structure formation. Micro- and nanoplastics introduce a novel stressor into this biological network.
Plastic particles may influence soil biota by altering habitat conditions, modifying moisture regimes, and introducing chemical substances associated with plastic materials. Such changes can affect microbial diversity, metabolic activity, and enzyme-mediated processes. Disruptions at the microbial level may propagate through the soil food web, influencing higher organisms and overall ecosystem functioning.
Because soil biological processes are tightly linked to carbon and nitrogen cycling, disturbances caused by micro- and nanoplastics may also influence greenhouse gas dynamics and long-term soil fertility. These potential effects highlight the importance of considering soil biology in assessments of plastic-related impacts.
Implications for Plants and Agro-Food Systems
The interaction between soil-borne micro- and nanoplastics and plants is of particular relevance for agriculture and food systems. Evidence indicates that small plastic particles can interact closely with plant roots and, under certain conditions, be taken up and transported within plant tissues. This raises concerns about crop performance, food quality, and exposure pathways within the food chain.
In addition to potential transfer, micro- and nanoplastics may influence plant physiology by affecting root development, water relations, and nutrient uptake. Reduced biomass production or altered stress responses could have economic implications for farmers, particularly in intensive or high-value cropping systems. These issues are especially relevant in the context of sustainable agriculture and safe food production.
InPlasTwin and the Advancement of Soil Plastic Research
In response to these challenges, InPlasTwin contributes to strengthening research capacity and scientific understanding related to micro- and nanoplastics in soils and agro-food systems. As a Horizon Europe Twinning project, InPlasTwin supports collaboration between institutions in Widening countries and leading European research centers, fostering knowledge exchange and long-term capacity building.
The project addresses critical questions related to the behavior and impacts of plastic-derived particles in soils, with particular emphasis on agricultural environments and food crops. By integrating soil science, environmental research, and agro-food perspectives, InPlasTwin promotes a holistic approach to understanding soil plastic contamination and its implications.
Equally important is the project’s focus on training, infrastructure development, and institutional strengthening, ensuring that expertise and capabilities persist beyond the project’s lifetime.
World Soil Day: Strengthening Awareness and Action
World Soil Day serves as a reminder that soils are finite and vulnerable resources that require long-term protection and responsible management. Micro- and nanoplastics represent an emerging form of contamination that challenges conventional approaches to soil protection due to their persistence and close interaction with biological systems.
Protecting soil health in this context requires coordinated efforts across research, policy, and practice. Key priorities include increasing awareness of plastic-related pressures on soils, supporting interdisciplinary research that links soil science with agriculture and food safety, and promoting land management practices that minimize plastic inputs. Reducing unnecessary plastic use, improving material management, and encouraging sustainable alternatives are essential steps toward preserving soil functions.
On this World Soil Day, the protection of soils from micro- and nanoplastic contamination should be recognized as an integral component of sustainable development. Healthy soils
form the foundation of resilient ecosystems, productive agriculture, and human well-being. Addressing emerging contaminants is therefore not only a scientific challenge, but a shared responsibility for current and future generations.
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