The Impact of Microplastics on Terrestrial Ecosystems

Plastic revolutionized the world, but at a grave cost. Due to its favorable properties, such as flexibility, durability and low production cost, its prevalence around the world skyrocketed, infiltrating nearly every ecosystem and household. However, the problem that arises is that, overtime plastic degrades into increasingly tiny particles, commonly known as microplastics. Microplastics are now found everywhere, from the tops of the mountain to the roots of trees.

What are Microplastics?

Plastic particles which less than 5mm in size are classified as microplastics [3]. Microplastics fall into two categories – primary microplastics and secondary microplastics. Secondary microplastics result from the degradation of bigger plastics due to erosion, physical abrasion etc., while primary microplastics are deliberately manufactured especially for cosmetics, detergents and beauty products [3].

It is widely believed that marine ecosystems are heavily affected by microplastics which is true to a certain extent; however, recent studies have shown that terrestrial ecosystems can act as even larger sinks for microplastics. Soil has been reported to be heavily contaminated with microplastics, and since plastic is not a natural constituent of the soil or the environment in general, its presence can interfere with natural biological and ecological processes.

The Effect of Microplastics on Terrestrial Ecosystems

Microplastics enter terrestrial ecosystems through a wide array of sources, including agricultural, domestic, construction, industrial and traffic related sources. Bio-solids and sludge, which are a form of organic solid waste are used as fertilizers on agricultural land, as well as water from wastewater treatment plants [1].

The agricultural sector contributes the most to microplastics in soil through the use of mulching, pipelines, greenhouse covers, and silage wraps. Mulching is the process in which plastic sheeting is used to cover the soil surface to protect its moisture, and control the temperature. Overtime degradation occurs, mainly due to UV radiation. Consequently, it is said that mulching increases the concentration of microplastics up to two-fold as compared to un-mulched soil [3]. Microplastic contamination in fruits and vegetables is a major concern as well when plastic mulch is used. Tilling and harvesting are agricultural processes which allow vertical distribution of microplastics through soil, since soil is turned over and deeper layers come in contact with microplastics.

Other sources which contribute to the accumulation of microplastics include domestic waste, construction and industrial waste as well and traffic-related waste. Road dust, for example, contains microplastics from the wear of tyres due to friction.

Factors Affecting Dispersal of Microplastics

The transport of microplastics through soil are influenced by varying external and internal conditions. For instance, drought conditions facilitate transfer of microplastics, while wind allows particulate matter to travel considerable distances, with studies reporting distances up to 95 km [2]. Areas near landfills and other micro plastic sinks have increased concentrations of microplastics.

Microplastics can also be transported vertically through soil by leaching. Porous soil, cracks and natural channels within the soil facilitate transport of microplastics into deeper layers of the soil [2]. Plants can capture airborne microplastics and plant roots, create bio pores (channels in the soil) which cause microplastics to be transported deeper into the soil. Ultimately, they reach groundwater sources through leaching, while surface runoff causes microplastics to be transported to rivers and river basins [2].

How Microplastics Affects the Soil?

The presence of microplastics can alter the physical properties of soil [3]. Soil texture and structure are affected, and the aeration of soil and its permeability are also affected. Moreover, natural processes such as carbon cycle, phosphorus cycle, nitrogen cycle and microbial activity are all negatively affected. Bioremediation is an important process conducted by microorganisms that plays an essential role in maintaining healthy ecosystems. Therefore, disturbances to the soil microbiota caused by microplastics may interfere in the natural remediation process in which microbes engage in the breakdown and detoxification of various substances like heavy metals and pollutants in the soil.

Some studies suggest that microplastics have a role in disturbing soil microbiota leading to a decrease in biodiversity. Natural hydrophobins present in the soil interact with the hydrophobic surface of microplastics, potentially altering their normal functions in communication between species and other ecosystem processes [1]. Plant growth is also being altered since germination and soil stability are impacted due to the presence of microplastics [2].

Furthermore, plasticizers and additives such as bisphenol A (BPA), heavy metals, and artificial dyes are usually added to plastics to enhance their properties [1]. These substances can easily adsorb onto plastic surfaces and often leach into the soil, causing toxicity. Terrestrial organisms can ingest or inhale plastics potentially increasing the risk of respiratory issues. In addition, plasticizers such as bisphenol A, and phthalates can disrupt endocrine activity affecting hormonal balance, causing estrogenic effects (excess estrogen production) and interfere with the reproductive activity in plants, and soil fauna [1].

Terrestrial organisms ingest microplastics and this way microplastics enter the food chains. As the trophic levels get higher, the concentration of microplastics get higher in organisms (bio-magnification). Cytotoxicity, cellular uptake and build up in the food chains is therefore a major concern. Marine foods like shell fish and salt have also shown microplastics.

Ways to Minimize Microplastics Proliferation

In this era, it is almost impossible to completely eliminate plastic and therefore microplastics, however the use of plastic needs to be controlled and minimized in order to prevent further damage to terrestrial ecosystems. One of the effective ways of reducing microplastics is to implement the ban on single-use plastics, such as plastic bags, straws, bottles etc. Another area of concern is the use of microbeads in beauty products like toothpaste and face washes; some governments have started implementing policies regarding the ban on microbeads.

Instead of using bio-solid for agriculture, it could be utilized in other industries for instance, the construction industry (brick making) [2]. Moreover, it is better to utilize safer materials for mulching like wood chips, compost, leaves etc., so that the concentration of microplastic in soil doesn’t escalate so much [2]. Improved technology for wastewater management and wastewater treatment should be utilized so that less microplastics make their way into terrestrial and aquatic ecosystems like better filters that can trap minuscule particles. Eco-friendly alternatives to food packaging and beverages should be used like paper bags, glass and reusable bottles.

Insiya Jafferjee, founder and CEO of ‘Shellworks’, has come up with a remarkable approach of plastic free packaging for beauty products. Her company utilizes microbes and bacteria and turns them into a material called ‘Vivomer’ which is rigid and durable like plastic but unlike plastic it doesn’t shed microplastics and can break down completely in soil [5].

Although biodegradable plastic is better than non-biodegradable plastic, it still produces microplastics when it degrades in soil [2]. Bio-based plastic which is basically plastic derived from renewable sources and doesn’t degrade harmful chemicals or microplastics is a recent discovery, usually manufactured using cornstarch or sugarcane and is compostable by microbial action [4]. Unfortunately, bioplastics also have their limitations: mass scale production may be challenging; plasticizers need to be added in order to enhance malleability and durability and thus it is an area which needs to be explored further.

Bottom Line

Microplastic pollution in terrestrial ecosystem is a major problem the world is currently facing. Terrestrial organisms including microbes, plants, humans and animals are all affected in some way or the other due to the increasing presence of microplastics in the environment and atmosphere. It is essential to address this issue, raise awareness, implement proactive policies and find sustainable alternatives to plastics to curb further damage to vulnerable terrestrial ecosystems.

References

1) de Souza Machado, A. A., Kloas, W., Zarfl, C., Hempel, S., & Rillig, M. C. (2018). Microplastics as an emerging threat to terrestrial ecosystems. Global Change Biology, 24(4), 1405–1416. https://doi.org/10.1111/gcb.14020

2)Roy, P., Mohanty, A. K., & Misra, M. (2022). Microplastics in ecosystems: their implications and mitigation pathways. Environmental Science: Advances, 1(1), 9–29. https://doi.org/10.1039/d1va00012h

3) Kang, Q., Zhang, K., Dekker, S. C., & Mao, J. (2025). Microplastics in soils: A comprehensive review. Science of The Total Environment, 960, 178298. https://doi.org/10.1016/j.scitotenv.2024.178298

4) Jabeen, M., Kainat Tarıq, & Syed Ubaid Hussain. (2024). Bioplastic an alternative to Plastic in Modern World: A Systemized Review. Environmental Research and Technology. https://doi.org/10.35208/ert.1467590

5) Gilmour, R. (2025). The boss who has found ‘nature’s answer to plastic.’ In Yahoo Finance. https://uk.finance.yahoo.com/news/shellworks-plastic-microbes-environment-business-050024897.html